A novel method for direct electronic "fast-timing" lifetime measurements of nuclear excited states via ³-³ coincidences using an array equipped with Nâ??N equally shaped very fast high-resolution LaBr3(Ce) scintillator detectors is presented. Analogous to the mirror symmetric centroid difference method, the generalized centroid difference method provides two independent "start" and "stop" time spectra obtained by a superposition of the N(N-1) ³-³ time difference spectra of the N detector fast-timing system. The two fast-timing array time spectra correspond to a forward and reverse gating of a specific ³-³ cascade. Provided that the energy response and the electronic time pick-off of the detectors are almost equal, a mean prompt response difference between start and stop events is calibrated and used as a single correction for lifetime determination. These combined fast-timing arrays mean ³-³ time-walk characteristics can be determined for 40keV
Boutachkov P, Braun N, Brock T, Singh BSN, Blazhev A, Liu Z, Wadsworth R, Górska M, Grawe H, Pietri S, Domingo-Pardo C, Faestermann T, Farinon F, Grebosz J, Kojuharov I, Kurz N, Nociforo C, Podolyák Z, Prochazka A, Steer S, Cáceres L, Engert T, Gerl J, Goel N, Hoischen R, Schaffner H, Weick H, Wollersheim HJ, Bettermann L, Finke F, Geibel K, Ilie G, Iwasaki H, Jolie J, Nyberg J, Reiter P, Scholl C, Söderström PA, Warr N, Eppinger K, Gottardo A, Hinke C, Krücken R, Pfützner M, Regan P, Rinta-Antila S, Rudolph D, Woods P, Ataç A, Merchán E (2011) Isomer and ²-decay spectroscopy of Tz=1 isotopes below the N=Z=50 shell gap, Journal of Physics: Conference Series312(SECTION 9)
The RISING setup at the GSI-FRS facility was used to investigate the isomer and beta decays in N
Mohammadi S, De Angrlis G, Axiotis M, Bazzacco D, Bizzeti PG, Brandolini F, Broda R, Bucurescu D, Farnea E, Gelletly W, Gadea A, Ionescu-Bujor M, Iordachescu A, Kröll T, Longdown S, Lunardi S, Marginean N, Martinez T, Medina N, Podolyák Z, Quintana B, Regan PH, Rubio B, Ur CA, Valiente Dobon JJ, Walker PM, Zhang YH (2006) Yrast states in 188,190 Os nuclei, International Journal of Modern Physics E15(8)pp. 1797-1802
Yrast states in neutron rich nuclei 188Os and 190Os have been populated using the deep-inelastic reaction 82Se + 192Os at 460 MeV beam bombarding energy. A thick 192Os target (>50 mg/cm2) with 0.2 mm Ta backing was used to stop all of the recoils in the target, minimising the broadening of the lines due to Doppler shift. High fold ³-³ coincidences were aquired with the 4À spectrometer GASP detector array. Three and two dimensional gamma-ray matrices were used to construct level schemes of the nuclei of interest up to an yrast state of 22. © World Scientific Publishing Company.
Bruce AM, Byrne AP, Dracoulis GD, Gelletly W, Kibedi T, Kondev FG, Purry CS, Regan PH, Thwaites C, Walker PM (1997) Systematics of K-pi=8(-) isomers in N=74 nuclei, PHYSICAL REVIEW C55(2)pp. 620-624 AMERICAN PHYSICAL SOC
Nasir T, Al-Sulaiti H, Regan PH (2012) Assessment of radioactivity in some soil samples of qatar by gamma-ray spectroscopy and the derived dose rates, Pakistan Journal of Scientific and Industrial Research Series A: Physical Sciences55(3)pp. 128-134
The activity concentrations of some natural and artificial radionuclides have been measured in soil samples by gamma-ray spectroscopy using a high purity germanium detector. From the obtained gamma-ray spectra, the activity concentrations of 238U and 232Th natural decay series and the long-lived naturally occurring radionuclide 40K have been determined, in addition to the fission product 137Cs. A wide range of different gamma-ray lines ranging from -100 keV up to 2.6 MeV, associated with the decay products of238U and232Th series have been analyzed independently to obtain more statistically significant overall results. The data have been analyzed, when secular equilibrium of the radionuclides is achieved within the samples. The weighted activity concentrations of 238U and232Th series vary from 4.4 to 64.4 and 0.8 to 7.6 Bq/kg, respectively. The activity concentrations of 40K and 137Cs have been found in the range of13.6 to 179.5 and 0.3 to 3.7 Bq/kg, respectively. Based on the measured activity concentrations, dose rate, radium equivalent, radiation hazard index and annual effective dose rates have been estimated. The values obtained are within the recommended safety limits.
Regan PH, Gamsworthy AB, Steer SJ, Pletri S, Podolyak Z, Rudolph D, Gorska M, Caceres L, Wemer-Malento E, Gerl J, Wollersheim HJ, Becker F, Bednarczyk P, Doornenbal PD, Geissel H, Grawe H, Grebosz J, Hoischen R, Kelic A, Kojouharov I, Kurz N, Montes F, Prokopowicz W, Saito T, Schaffner H, Tashenov S, Heinz A, Pfuetzner M, Kurtukian-Nieto T, Benzoni G, Hellstroem M, Jungclaus A, Andersson L-L, Atanasova L, Balabanski DL, Bentley MA, Blank B, Blazhev A, Brandau C, Brown J, Bruce AM, Camera F, Catford WN, Cullen IJ, Dombradi Z, Estevez E, Fahlander C, Gelletly W, Ilie G, Johansson EK, Jolie J, Jones GA, Kmiecik M, Kondev G, Lalkovski S, Liu Z, Maj A, Myalski S, Schwertel S, Shizuma T, Simons AJ, Walker PM, Wieland O (2007) First results from the stopped RISING campaign at GSI: The mapping of isomeric decays in highly exotic nuclei, Six International Conference of the Balkan Physical Union899pp. 19-22 AMER INST PHYSICS
Williams SJ, Jenneson PM, Garrett PE, Regan PH, Andreoiu C, Ball GC, Chakrawarthy RS, Daoud JJ, Grinyer GF, Hackman G, Hyland B, Mlwilo NA, Morton AC, Pearson CJ, Ressler JJ, Schumaker MA, Smith MB, Svensson CE, Dobon JJV (2005) Testing the integration of BaF2 detectors into the 8 pi array: fast-timing measurements at TRIUMF, JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS31(10)pp. S1979-S1984 IOP PUBLISHING LTD
Pfutzner M, Armbruster P, Baumann T, Benlliure J, Bernas M, Catford WN, Cortina-Gil D, Daugas JM, Geissel H, Gorska M, Grawe H, Grzywacz R, Hellstrom M, Iwasa N, Janas Z, Junghans AR, Karny M, Leenhardt S, Lewitowicz M, Mueller AC, de Oliviera F, Regan PH, Rejmund M, Rykaczewski K, Summerer K (1998) New isotopes and isomers produced by the fragmentation of U-238 at 1000 MeV/nucleon, PHYSICS LETTERS B444(1-2)pp. 32-37 ELSEVIER SCIENCE BV
Regan PH (2012) From RISING to the DESPEC fast-timing project within NUSTAR at FAIR: sub-nanosecond nuclear timing spectroscopy with LaBr3 scintillators., Appl Radiat Isot70(7)pp. 1125-1130
This paper summarises a presentation given at the IRRMA8 conference in June 2011 which reviewed briefly the topic of current research studies in the evolution of nuclear structure with changing proton and neutron numbers. A short review of relevant contemporary spectroscopic studies of the structure of nuclei with highly exotic N/Z ratios using projectile fragmentation and fission reactions is given, together with an overview of some of the physics research aims to be attacked using the proposed Decay Spectroscopy (DESPEC) LaBr3 Fast-Timing gamma-ray array for the NUSTAR project at the upcoming Facility for Anti-Proton and Ion Research (FAIR). Examples of recent results using both 'isomer' and ²--delayed gamma-ray decay measurements with the Stopped RISING hyper-pure germanium array at GSI are summarised and used to highlight some of the fundamental physics studies which are expected to become available in this area of research in the coming decade. Examples of the performance of cerium-doped LaBr3 detectors from 'in-beam' test experiments are presented together with initial plans for the geometry of the planned multi-detector LaBr3(Ce) array for DESPEC.
Malain D, Regan PH, Bradley DA, Matthews M, Al-Sulaiti HA, Santawamaitre T (2012) An evaluation of the natural radioactivity in Andaman beach sand samples of Thailand after the 2004 tsunami., Appl Radiat Isot70(8)pp. 1467-1474
Following the 2004 'Boxing day' tsunami, a determination has been made of the activity concentrations of (226)Ra, (232)Th and (40)K in beach sand samples which have been collected from various locations along the Andaman coast of the Thai peninsula. Use has been made of a HPGe detector-based, low-background gamma-ray counting system. The natural radioactivity levels of (226)Ra, (232)Th and (40)K measured from these samples was found to lie in the range 1.6-52.5, 0.3-73.9 and 2.8-1111.9Bq/kg respectively for the west coast and 3.5-83.1, 4.5-42.0, and 9.6-1376 Bq/kg respectively for the east coast. The radioactivity concentrations of (226)Ra, (232)Th and (40)K along the Andaman coast are comparable to that of the east coast, which was not exposed to the tsunami. The corresponding annual effective dose varies from 1.6-105.9 ¼Sv/y with a mean value of 59.1 ± 0.3 ¼Sv/y, significantly lower than the worldwide average as reported by United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) (2000).
Zhang YH, Podolyak Z, de Angelis G, Gadea A, Ur C, Lunardi S, Marginean N, Rusu C, Schwengner R, Kroll T, Napoli DR, Menegazzo R, Bazzacco D, Farnea E, Lenzi S, Martinez T, Axiotis M, Tonev D, Gelletly W, Langdown S, Regan PH, Dobon JJV, von Oertzen W, Rubio B, Quintana B, Medina N, Broda R, Bucurescu D, Ionescu-Bujor M, Iordachescu A (2004) Stability of the N=50 shell gap in the neutron-rich Rb, Br, Se, and Ge isotones,PHYSICAL REVIEW C70(2)ARTN 024301 AMERICAN PHYSICAL SOC
Descovich M, Nolan PJ, Boston AJ, Dobson J, Gros S, Cresswell JR, Simpson J, Lazarus I, Regan PH, Valiente-Dobon JJ, Sellin P, Pearson CJ (2005) The position response of a large-volume segmented germanium detector, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT553(3)pp. 512-521 ELSEVIER SCIENCE BV
Andgren K, Ashley SF, Regan PH, McCutchan EA, Zamfir NV, Amon L, Cakirli RB, Casten RF, Clark RM, Gurdal G, Keyes KL, Meyer DA, Erduran MN, Papenberg A, Pietralla N, Plettner C, Rainovski G, Ribas RV, Thomas NJ, Vinson J, Warner DD, Werner V, Williams E (2005) RDM lifetime measurements in Cd-107, JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS31(10)pp. S1563-S1568 IOP PUBLISHING LTD
Williams SJ, Bentley MA, Warner DD, Bruce AM, Cameron JA, Carpenter MP, Fallon P, Frankland L, Gelletly W, Janssens RVF, Joss DT, O'Leary CD, Lister CJ, Poves A, Regan PH, Reiter P, Rubio B, Seweryniak D, Svensson CE, Vincent SM (2003) Anomalous Coulomb matrix elements in the f(7/2) shell, PHYSICAL REVIEW C68(1)ARTN 011301 AMERICAN PHYSICAL SOC
Janas Z, Chandler C, Blank B, Regan PH, Bruce AM, Catford WN, Curtis N, Czajkowski S, Dessagne P, Fleury A, Gelletly W, Giovinazzo J, Grzywacz R, Lewitowicz M, Longour C, Marchand C, Miehe C, Orr NA, Page RD, Pearson CJ, Pravikoff MS, Reed AT, Saint-Laurent MG, Sheikh JA, Vincent SM, Wadsworth R, Warner DD, Winfield JS (1999) Observation of the Z=N+1 nuclei Y-77(39), Zr-79(40), and Mo-83(42), PHYSICAL REVIEW LETTERS82(2)pp. 295-298 AMERICAN PHYSICAL SOC
Britton R, Burnett JL, Davies AV, Regan PH (2014) Monte Carlo characterisation of a Compton suppressed broad-energy HPGe detector, Journal of Radioanalytical and Nuclear Chemistry300(3)pp. 1253-1259
GEANT4 Monte Carlo simulations have been successfully utilised to characterise a Compton suppressed broad-energy HPGe detector. The detector setup has been fully recreated in the simulation, which has been optimised to consistently reproduce the detector response. The peak efficiencies for both the primary BEGe detector and NaI(Tl) guard detectors agree with the simulated values for multiple test sources within 3 %. Compton suppression has also been simulated, with good agreement seen between the simulated and actual CSF values (<10 %) for multiple radionuclides. A secondary reference source was also simulated, which contained up to 30 radionuclides in a different geometry to that of the previous source. This showed excellent agreement with experimental data in both unsuppressed and suppressed modes of operation. © 2014 Akadémiai Kiadó.
Vincent SM, Regan PH, Mohammadi S, Blumenthal D, Carpenter M, Davids CN, Gelletly W, Ghugre SS, Henderson DJ, Janssens RVF, Hjorth-Jensen M, Kharraja B, Lister CJ, Pearson CJ, Seweryniak D, Schwartz J, Simpson J, Warner DD (1999) Near yrast study of the fpg shell nuclei Ni-58, Cu-61, and Zn-61, PHYSICAL REVIEW C60(6)ARTN 064308 AMER PHYSICAL SOC
Pietri S, Jungclaus A, Gorska M, Grawe H, Pfuetzner M, Caceres L, Detistov P, Lalkovski S, Modamio V, Podolyak Z, Regan PH, Rudolph D, Walker J, Werner-Malento E, Bednarczyk P, Doornenbal P, Geissel H, Gerl J, Grebosz J, Kojouharov I, Kurz N, Prokopowicz W, Schaffner H, Wollersheim HJ, Andgren K, Benlliure J, Benzoni G, Bruce AM, Casarejos E, Cederwall B, Crespi FCL, Hadinia B, Hellstrom M, Hoischen R, Ilie G, Khaplanov A, Kmiecik M, Kumar R, Maj A, Mandal S, Montes F, Myalski S, Simpson G, Steer SJ, Tashenov S, Wieland O (2011) First observation of the decay of a 15(-) seniority v=4 isomer in Sn-128,PHYSICAL REVIEW C83(4)ARTN 044328 AMER PHYSICAL SOC
Regan PH, Yamamoto AD, Xu FR, Wu CY, Macchiavelli AO, Cline D, Smith JF, Freeman SJ, Valiente-Dobon JJ, Andgren K, Chakrawarthy RS, Cromaz M, Fallon P, Gelletly W, Gorgen A, Hayes A, Hua H, Langdown SD, Lee IY, Pearson CJ, Podolyak Z, Teng R, Wheldon C (2003) Binary-reaction spectroscopy of Mo-99,Mo-100: Intruder alignment systematics in N=57 and N=58 isotones,PHYSICAL REVIEW C68(4)ARTN 044313 AMERICAN PHYSICAL SOC
Hoischen R, Rudolph D, Ma HL, Montuenga P, Hellstrom M, Pietri S, Podolyak Z, Regan PH, Garnsworthy AB, Steer SJ, Becker F, Bednarczyk P, Caceres L, Doornenbal P, Gerl J, Gorska M, Grebosz J, Kojouharov I, Kurz N, Prokopowicz W, Schaffner H, Wollersheim HJ, Andersson L-L, Atanasova L, Balabanski DL, Bentley MA, Blazhev A, Brandau C, Brown JR, Fahlander C, Johansson EK, Jungclaus A (2011) Isomeric mirror states as probes for effective charges in the lower pf shell, JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS38(3)ARTN 035104 IOP PUBLISHING LTD
Benzoni G, Azaiez F, Leoni S, Battacharyya S, Borcea R, Bracco A, Corradi L, Curien D, De France G, Dombradi Z, Fioretto E, Franchoo S, Grevy S, Ibrahim F, Iulian S, Mukherjee G, Navin A, Pollarolo G, Redon N, Regan PH, Rejmund M, Schmitt C, Sletten G, Sohler D, Stanoiu M, Szilner S, Verney D (2006) In-beam ³ spectroscopy using DIC with a radioactive Ne beam, AIP Conference Proceedings853pp. 49-54
The preferred production mechanisms used to investigate the region of light nuclei, such as O, Ne and F, have been transfer reactions and, more recently, two-step fragmentation. Multi-nucleon transfer reactions can be an important complementary tool to populate this mass region. Deep-inelastic and multi-nucleon transfer reactions have been largely used to study heavier systems, however no information is yet available regarding the effectiveness of these reaction mechanisms going towards lighter nuclei. In this proceeding we present promising preliminary results from an experiment performed with a radioactive 24Ne beam from SPIRAL facility at GANIL using the VAMOS spectrometer in conjunction with the EXOGAM array. © 2006 American Institute of Physics.
Neyens G, Georgiev G, Grzywacz R, Hass M, Santos FD, Lewitowicz M, Balabanski DL, Bingham C, Borcea C, Coulier N, Coussement R, Daugas JM, Defrance G, Goldring G, Gorska M, Grawe H, O'Leary C, Macovei I, Mach H, Page R, Pfutzner M, Penionzkevich YE, Podolyak Z, Regan PH, Rykaczewski K, Sawicka M, Smirnova NA, Sobolev Y, Teughels S, Vyvey K (2002) g-factors of isomers around N approximate to 40, Z approximate to 28 from time-dependent Larmor precession on spin-aligned projectile-like fragments, NUCLEAR PHYSICS A701pp. 403C-409C ELSEVIER SCIENCE BV
Gottardo A, Valiente-Dobón JJ, Benzoni G, Gadea A, Lunardi S, Boutachkov P, Bruce AM, Górska M, Grebosz J, Pietri S, Podolyák Z, Pfützner M, Regan PH, Weick H, Alcántara Núñez J, Algora A, Al-Dahan N, de Angelis G, Ayyad Y, Alkhomashi N, Allegro PRP, Bazzacco D, Benlliure J, Bowry M, Bracco A, Bunce M, Camera F, Casarejos E, Cortes ML, Crespi FCL, Corsi A, Denis Bacelar AM, Deo AY, Domingo-Pardo C, Doncel M, Dombradi Z, Engert T, Eppinger K, Farrelly GF, Farinon F, Farnea E, Geissel H, Gerl J, Goel N, Gregor E, Habermann T, Hoischen R, Janik R, John PR, Klupp S, Kojouharov I, Kurz N, Lenzi SM, Leoni S, Mandal S, Menegazzo R, Mengoni D, Million B, Modamio V, Morales AI, Napoli DR, Naqvi F, Nicolini R, Nociforo C, Prochazka A, Prokopowicz W, Recchia F, Ribas RV, Reed MW, Rudolph D, Sahin E, Schaffner H, Sharma A, Sitar B, Siwal D, Steiger K, Strmen P, Swan TPD, Szarka I, Ur CA, Walker PM, Wieland O, Wollersheim HJ (2013) New ¼s isomers in the neutron-rich 210Hg nucleus,Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics725(4-5)pp. 292-296 Neutron-rich nuclei in the lead region, beyond N=126, have been studied at the FRS-RISING setup at GSI, exploiting the fragmentation of a primary uranium beam. Two isomeric states have been identified in 210Hg: the 8+ isomer expected from the seniority scheme in the ½g9/2 shell and a second one at low spin and low excitation energy. The decay strength of the 8+ isomer confirms the need of effective three-body forces in the case of neutron-rich lead isotopes. The other unexpected low-lying isomer has been tentatively assigned as a 3- state, although this is in contrast with theoretical expectations. © 2013 Elsevier B.V..
Valencia E, Algora A, Tain JL, Rice S, Agramunt J, Zakari-Issoufou AA, Äystö J, Bowry M, Bui VM, Caballero-Folch R, Cano-Ott D, Eloma V, Eronen T, Estevez E, Farrelly GF, Fallot M, Garcia A, Gelletly W, Gomez-Hornillos MB, Gorlychev V, Hakala J, Jokinen A, Jordan MD, Kankainen A, Kondev FG, Martinez T, Mendoza E, Molina F, Moore I, Perez A, Podolyak Z, Penttilä H, Porta A, Regan PH, Rissanen J, Rubio B, Weber C (2014) Gamma/neutron competition above the neutron separation energy in delayed neutron emitters, EPJ Web of Conferences66
To study the ²-decay properties of some well known delayed neutron emitters an experiment was performed in 2009 at the IGISOL facility (University of Jyväskylä in Finland) using Total Absorption -ray Spectroscopy (TAGS) technique. The aim of these measurements is to obtain the full ²-strength distribution below the neutron separation energy (Sn) and the ³/neutron competition above. This information is a key parameter in nuclear technology applications as well as in nuclear astrophysics and nuclear structure. Preliminary results of the analysis show a significant ³-branching ratio above Sn. © Owned by the authors, published by EDP Sciences, 2014.
Caamano M, Walker PM, Regan PH, Pfutzner M, Podolyak Z, Gerl J, Hellstrom M, Mayet P, Mineva MN, Aprahamian A, Benlliure J, Bruce AM, Butler PA, Gil DC, Cullen DM, Doring J, Enqvist T, Fox C, Narro JG, Geissel H, Gelletly W, Giovinazzo J, Gorska M, Grawe H, Grzywacz R, Kleinbohl A, Korten W, Lewitowicz M, Lucas R, Mach H, O'Leary CD, De Oliveira F, Pearson CJ, Rejmund F, Rejmund M, Sawicka M, Schaffner H, Schlegel C, Schmidt K, Schmidt KH, Stevenson PD, Theisen C, Vives F, Warner DD, Wheldon C, Wollersheim HJ, Wooding S, Xu F, Yordanov O (2005) Isomers in neutron-rich A approximate to 190 nuclides from Pb-208 fragmentation, EUROPEAN PHYSICAL JOURNAL A23(2)pp. 201-215 SPRINGER
Georgiev G, Balabanski DL, Bingham C, Borcea C, Coulier N, Coussement R, Daugas JM, Defrance G, De Oliveira Santos F, Goldring G, Górska M, Grawe H, Grzywacz R, Hass M, O'Leary C, Lewitowicz M, Mach H, Macovei I, Page R, Pfützner M, Penionzkevich YE, Podolyák Z, Regan PH, Rykaczewski K, Sawicka M, Smirnova NA, Sobolev YG, Stanoiu M, Teughels S, Vyvey K, Neyens G (2001) Measurement of the g factors of isomers near the proposed N H 40 subshell closure, Physics of Atomic Nuclei64(7)pp. 1181-1185
We report results from a pioneering experiment to measure the g factors of isomeric states of neutron-rich nuclei around 68Ni, far from the valley of ² stability. For the first time, the time-dependent perturbed angular distribution method was applied in combination with the heavy-ion-³ correlation technique to study g factors of spin-aligned isomers produced in a projectile fragmentation reaction and mass-separated. Some technical aspects are discussed and illustrated with preliminary results. © 2001 MAIK "Nauka/Interperiodica".
Roberts OJ, Bruce AM, Browne F, Marginean N, Alexander T, Alharbi T, Bucurescu D, Deleanu D, Delion D, Filipescu D, Fraile L, Gheorghe I, Ghia D, Glodariu T, Ivanova D, Kisyov S, Marginean R, Mason PJR, Mihai C, Mulholland K, Negret A, Nia C, Olaizola B, Pascu S, Söderström PA, Regan PH, Sava T, Stroe L, Toma S, Townsley C (2013) Half-life measurements of excited states in 132Te, 134Xe, Acta Physica Polonica B44(3)pp. 403-406
The 7Li+130Te reaction was used to populate excited states in 132Te and 134Xe. The experiment at the Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest, Romania, used an array of high-purity germanium (HPGe) and cerium-doped lanthanum bromide (LaBr3(Ce)) detectors to measure sub-nanosecond half-lives using fast-timing techniques. The half-lives of the yrast 4+ and 6+ levels were measured in the N = 80 nuclei 132Te and 132Xe, respectively. An upper limit of T1=2d 40 ps was assigned to the 4+ level in 132Te and T1=2 = 1075(155) ps was assigned to the 6+ level in 132Xe. The systematics of the B(E2) strengths around the N = 82 shell closure are discussed.
Zakari-Issoufou AA, Porta A, Fallot M, Algora A, Tain JL, Valencia E, Rice S, Agramunt J, Äystö J, Bowry M, Bui VM, Caballero-Folch R, Cano-Ott D, Eloma V, Estévez E, Farrelly GF, Garcia A, Gelletly W, Gomez-Hornillos MB, Gorlychev V, Hakala J, Jokinen A, Jordan MD, Kankainen A, Kondev FG, Martinez T, Mendoza E, Molina F, Moore I, Perez A, Podolyak Z, Penttilä H, Regan PH, Rissanen J, Rubio B, Weber C (2014) Results of fission products ² decay properties measurement performed with a total absorption spectrometer, EPJ Web of Conferences66
²-decay properties of fission products are very important for applied reactor physics, for instance to estimate the decay heat released immediately after the reactor shutdown and to estimate the ½ flux emitted. An accurate estimation of the decay heat and the ½ emitted flux from reactors, are necessary for purposes such as reactors operation safety and non-proliferation. In order to improve the precision in the prediction for these quantities, the bias due to the Pandemonium effect affecting some important fission product data has to be corrected. New measurements of fission products ²-decay, not sensitive to this effect, have been performed with a Total Absorption Spectrometer (TAS) at the JYFL facility of Jyväskylä. An overview of the TAS technique and first results from the 2009 campaign will be presented. © Owned by the authors, published by EDP Sciences, 2014.
Jones GA, Podolyak Z, Walker PM, Regan PH, de Angelis G, Axiotis M, Bazzacco D, Bizzeti PG, Brandolini F, Broda R, Bucurescu D, Farnea E, Gelletly W, Gadea A, Ionescu-Bujor M, Iordachescu A, Kroll T, Langdown SD, Lunardi S, Marginean N, Martinez T, Medina NH, Quintana B, Rubio B, Ur CA, Valiente-Dobon JJ, Williams SJ, Zhang YH (2005) Population of yrast states in Os-191 using deep-inelastic reactions, JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS31(10)pp. S1891-S1894 IOP PUBLISHING LTD
Garnsworthy AB, Lister CJ, Regan PH, Blank BB, Cullen IJ, Gros S, Henderson DJ, Jones GA, Liu Z, Seweryniak D, Shumard BR, Thompson NJ, Williams SJ, Zhu S (2008) Optimizing recoil-isomer tagging with the Argonne fragment mass analyzer, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT594(2)pp. 184-187 ELSEVIER SCIENCE BV
Lalkovski S, Bruce AM, Bacelar AMD, Górska M, Pietri S, Podolyák Z, Bednarczyk P, Caceres L, Casarejos E, Cullen IJ, Doornenbal P, Farrelly GF, Garnsworthy AB, Geissel H, Gelletly W, Gerl J, Gr)bosz J, Hinke C, Ilie G, Jaworski G, Kisyov S, Kojouharov I, Kurz N, Myalski S, Palacz M, Prokopowicz W, Regan PH, Schaffner H, Steer S, Tashenov S, Walker PM, Wollersheim HJ, Zhekova M (2012) Single-particle isomeric states in 121Pd and 117Ru,Journal of Physics: Conference Series366(1) Neutron-rich nuclei were populated in a relativistic fission of 238U. Gamma-rays with energies of 135 keV and 184 keV were associated with two isomeric states in 121Pd and 117Ru. Half-lives of 0.63(5) ¼s and 2.0(3) ¼s were deduced and the isomeric states were interpreted in terms of prolate deformed single-particle states.
Alharbi T, Regan PH, MÎrginean N, Podolyák Z, Bajoga A, Britton R, Bucurescu D, Deleanu D, Filipescu D, GhitÎ D, Glodariu T, Mihai C, Mulholland K, MÎrginean R, Negret A, Nita CR, Patel Z, Roberts OJ, Stroe L, Sava T, Townsley C, Zamfir NV (2014) Sub-nanosecond Half-life Measurement of the Yrast IÀ=5- State in the N=78 Nucleus Ce58136 using Fast-timing Coincident Gamma-ray Spectroscopy, Nuclear Data Sheets120pp. 59-61
We report on the measurement of the half-life of the yrast IÀ=5- state in the transitional nucleus 136Ce using a combined HPGe-LaBr3(Ce) scintillator gamma-ray detection array. The measured value for the E1 decay is approximately half a nanosecond, which corresponds to an E1 decay strength of approximately 2×10-6 Wu. This value is in line with single-particle type E1 decays in this mass region and suggests no sign of additional K-hindrance associated with axially symmetric quadrupole deformations observed for lighter cerium isotopes. © 2014 Elsevier Inc.
Ressler JJ, Beausang CW, Casten RF, Zamfir NV, Ai H, Amro H, Babilon M, Cakirli RB, Caggiano JA, Gurdal G, Heinz A, Hughes RO, Langdown SD, McCutchan EA, Meyer DA, Plettner C, Qian J, Regan PH, Sciacchitano MJS, Thomas NJ, Williams E, Yamamoto A (2005) Isomers and seniority in the trans-Pb nuclei, JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS31(10)pp. S1605-S1610 IOP PUBLISHING LTD
Cieplicka N, Fornal B, Maier KH, Szpak B, Broda R, Krolas W, Pawlat T, Wrzesinski J, Janssens RVF, Carpenter MP, Chiara CJ, Hoffman CR, Kondev FG, Lauritsen T, Zhu S, Podolyak Z, Bowry M, Bunce M, Gelletly W, Kempley R, Reed M, Regan P, Walker P, Wilson E, Deo AY, Dracoulis G, Lane G, Rodriguez-Triguero C (2014) ANGULAR DISTRIBUTIONS OF gamma RAYS FROM Bi-210 PRODUCED IN Pb-208+Pb-208 DEEP-INELASTIC REACTIONS,ACTA PHYSICA POLONICA B45(2)pp. 205-210 WYDAWNICTWO UNIWERSYTETU JAGIELLONSKIEGO
Lorusso G, Shearman R, Regan PH, Judge SM, Bell S, Collins SM, Larijani C, Ivanov P, Jerome SM, Keightley JD, Lalkovski S, Pearce AK, Podolyak Z (2016) Development of the NPL gamma-ray spectrometer NANA for traceable nuclear decay and structure studies,APPLIED RADIATION AND ISOTOPES109pp. 507-511 PERGAMON-ELSEVIER SCIENCE LTD
Jimenez MJL, Blank B, Chartier M, Czajkowski S, Dessagne P, de France G, Giovinazzo J, Karamanis D, Lewitowicz M, Maslov V, Miehe C, Regan PH, Stanoiu M, Wiescher M (2002) Half-life measurements of proton-rich Kr-78 fragments, PHYSICAL REVIEW C66(2)ARTN 025803 AMERICAN PHYSICAL SOC
REGAN PH, STUCHBERY AE, ANDERSSEN SS (1995) MEASUREMENT OF THE G-FACTOR OF THE YRAST-10(+)-STATE IN CD-11O, NUCLEAR PHYSICS A591(3)pp. 533-547 ELSEVIER SCIENCE BV
Wolf A, Berant Z, Zamfir NV, Brenner DS, McCutchan EA, Ai H, Casten RF, Dusling K, Heinz A, Meyer DA, Millman EA, Pietralla N, Plettner C, Qian J, Regan PH, Swanson D, Vinson J, Williams E, Winkler R (2005) g factor of the 2(1)(+) state of Er-160, PHYSICAL REVIEW C72(2)ARTN 027301 AMERICAN PHYSICAL SOC
Mason PJR, Alharbi T, Regan PH, Marginean N, Podolyak Z, Simpson EC, Alkhomashi N, Bender PC, Bowry M, Bostan M, Bucurescu D, Bruce AM, Cata-Danil G, Cata-Danil I, Chakrabarti R, Deleanu D, Detistov P, Erduran MN, Filipescu D, Garg U, Glodariu T, Ghita D, Ghugre SS, Kusoglu A, Marginean R, Mihai C, Nakhostin M, Negret A, Pascu S, Triguero CR, Sava T, Sinha AK, Stroe L, Suliman G, Zamfir NV (2012) Half-life of the I-pi=4(-) intruder state in P-34: M2 transition strengths approaching the island of inversion,PHYSICAL REVIEW C85(6)ARTN 064303 AMER PHYSICAL SOC
Lewitowicz M, Blank B, Daugas JM, Grawe H, Grzywacz R, Neyens G, Pfutzner M, Regan PH, Rykaczewski K (2001) Nuclear structure studies by means of short-lived isomers at intermediate energies, NUCLEAR PHYSICS A682pp. 175C-182C ELSEVIER SCIENCE BV
Grodner E, Gadea A, Sarriguren P, Lenzi SM, Grebosz J, Valiente-Dobón JJ, Algora A, Górska M, Regan PH, Rudolph D, de Angelis G, Agramunt J, Alkhomashi N, Amon Susam L, Bazzacco D, Benlliure J, Benzoni G, Boutachkov P, Bracco A, Caceres L, Cakirli RB, Crespi FC, Domingo-Pardo C, Doncel M, Dombrádi Z, Doornenbal P, Farnea E, Ganio?lu E, Gelletly W, Gerl J, Gottardo A, Hüyük T, Kurz N, Leoni S, Mengoni D, Molina F, Morales AI, Orlandi R, Oktem Y, Page RD, Perez D, Pietri S, Podolyák Z, Poves A, Quintana B, Rinta-Antila S, Rubio B, Nara Singh BS, Steer AN, Verma S, Wadsworth R, Wieland O, Wollersheim HJ (2014) Hindered Gamow-Teller decay to the odd-odd N=Z (62)Ga: absence of proton-neutron T=0 condensate in A=62., Phys Rev Lett113(9)
Search for a new kind of superfluidity built on collective proton-neutron pairs with aligned spin is performed studying the Gamow-Teller decay of the T=1, J(À)=0+ ground state of (62)Ge into excited states of the odd-odd N=Z nucleus (62)Ga. The experiment is performed at GSI Helmholtzzentrum für Shwerionenforshung with the (62)Ge ions selected by the fragment separator and implanted in a stack of Si-strip detectors, surrounded by the RISING Ge array. A half-life of T1/2=82.9(14) ms is measured for the (62)Ge ground state. Six excited states of (62)Ga, populated below 2.5 MeV through Gamow-Teller transitions, are identified. Individual Gamow-Teller transition strengths agree well with theoretical predictions of the interacting shell model and the quasiparticle random phase approximation. The absence of any sizable low-lying Gamow-Teller strength in the reported beta-decay experiment supports the hypothesis of a negligible role of coherent T=0 proton-neutron correlations in (62)Ga.
Caamano M, Walker PM, Regan PH, Pearson CJ, Podolyak Z, Mayet P, Gerl J, Schlegel C, Hellstrom M, Mineva M, Pfutzner M (2001) Isomeric decays in Pt-200, ACTA PHYSICA POLONICA B32(3)pp. 763-766 ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS
Al-Dahan N, Podolyak Z, Regan PH, Steer SJ, Alkhomashi N, Bacelar AMD, Gorska M, Pietri SB, Gelletly W, Walker PM, Farrelly G, Morales AI, Deo AY, Cullen IJ, Gerl J, Domingo-Pardo C, Verma S, Swan T, Wollersheim HJ, Bruce AM, Lalkovski S, Benlliure J, Algora A, Boutachkov P, Bracco A, Calore E, Casarejos E, Detistov P, Dombradi Z, Doncel M, Farinon F, Geissel H, Goel N, Grebosz J, Hoischen R, Kojouharov I, Leoni S, Molina F, Montanari D, Musumarra A, Nicolini R, Napoli DR, Nociforo C, Rubio B, Prochazka A, Rudolph D, Strmen P, Szarka I, Valiente-Dobon JJ, Weick H (2009) Structure of N >= 126 nuclei produced in fragmentation of (238)U,CAPTURE GAMMA-RAY SPECTROSCOPY AND RELATED TOPICS1090pp. 145-148 AMER INST PHYSICS
Lalkovski S, Bruce AM, Jungclaus A, Górska M, Pfützner M, Cáceres L, Naqvi F, Pietri S, Podolyák Z, Simpson GS, Andgren K, Bednarczyk P, Beck T, Benlliure J, Benzoni G, Casarejos E, Cederwall B, Crespi FCL, Cuenca-García JJ, Cullen IJ, Denis Bacelar AM, Detistov P, Doornenbal P, Farrelly GF, Garnsworthy AB, Geissel H, Gelletly W, Gerl J, Grebosz J, Hadinia B, Hellström M, Hinke C, Hoischen R, Ilie G, Jaworski G, Jolie J, Khaplanov A, Kisyov S, Kmiecik M, Kojouharov I, Kumar R, Kurz N, Maj A, Mandal S, Modamio V, Montes F, Myalski S, Palacz M, Prokopowicz W, Reiter P, Regan PH, Rudolph D, Schaffner H, Sohler D, Steer SJ, Tashenov S, Walker J, Walker PM, Weick H, Werner-Malento E, Wieland O, Wollersheim HJ, Zhekova M (2013) Core-coupled states and split proton-neutron quasiparticle multiplets in 122-126Ag,Physical Review C - Nuclear Physics87(3) Neutron-rich silver isotopes were populated in the fragmentation of a 136Xe beam and the relativistic fission of 238U. The fragments were mass analyzed with the GSI Fragment Separator and subsequently implanted into a passive stopper. Isomeric transitions were detected by 105 high-purity germanium detectors. Eight isomeric states were observed in 122-126Ag nuclei. The level schemes of 122,123,125Ag were revised and extended with isomeric transitions being observed for the first time. The excited states in the odd-mass silver isotopes are interpreted as core-coupled states. The isomeric states in the even-mass silver isotopes are discussed in the framework of the proton-neutron split multiplets. The results of shell-model calculations, performed for the most neutron-rich silver nuclei are compared to the experimental data. © 2013 American Physical Society.
Bucurescu D, Podolyak Z, Rusu C, de Angelis G, Zhang YH, Cata-Danil G, Cata-Danil I, Ivascu M, Marginean N, Marginean R, Mihailescu LC, Suliman GA, Regan PH, Gelletly W, Langdown SD, Dobon JJV, Bazzacco D, Lunardi S, Ur CA, Axiotis M, Gadea A, Farnea E, Ionescu-Bujor M, Iordachescu A, Kroll T, Martinez T, Bizzetti PG, Broda R, Medina NH, Quintana B, Rubio B (2005) High-spin states in the nuclei Y-91 and Nb-95,PHYSICAL REVIEW C71(3)ARTN 034315 AMERICAN PHYSICAL SOC
Podolyak Z, Mohammadi S, De Angelis G, Zhang YH, Axiotis M, Bazzacco D, Bizzeti PG, Brandolini F, Broda R, Bucurescu D, Farnea E, Gelletly W, Gadea A, Ionescu-Bujor M, Iordachescu A, Kroll T, Langdown SD, Lunardi S, Marginean N, Martinez T, Medina NH, Quintana B, Regan PH, Rubio B, Ur CA, Valiente-Dobon JJ, Walker PM (2004) Structure of neutron-rich nuclei from deep-inelastic reactions, INTERNATIONAL JOURNAL OF MODERN PHYSICS E-NUCLEAR PHYSICS13(1)pp. 123-126 WORLD SCIENTIFIC PUBL CO PTE LTD
Jungclaus A, Caceres L, Gorska M, Pfutzner M, Pietri S, Werner-Malento E, Grawe H, Langanke K, Martinez-Pinedo G, Nowacki F, Poves A, Cuenca-Garcia JJ, Rudolph D, Podolyak Z, Regan PH, Detistov P, Lalkovski S, Modamio V, Walker J, Bednarczyk P, Doornenbal P, Geissel H, Gerl J, Grebosz J, Kojouharov I, Kurz N, Prokopowicz W, Schaffner H, Wollersheim HJ, Andgren K, Benlliure J, Benzoni G, Bruce AM, Casarejos E, Cederwall B, Crespi FCL, Hadinia B, Hellstrom M, Hoischen R, Ilie G, Jolie J, Khaplanov A, Kmiecik M, Kumar R, Maj A, Mandal S, Montes F, Myalski S, Simpson GS, Steer SJ, Tashenov S, Wieland O (2007) Observation of isomeric decays in the r-process waiting-point nucleus Cd-130(82),PHYSICAL REVIEW LETTERS99(13)ARTN 132501 AMER PHYSICAL SOC
Jones GA, Regan PH, Walker PM, Podolyak Z, Stevenson PD, Carpenter MP, Carroll JJ, Chakrawarthy RS, Chowdhury P, Garnsworthy AB, Janssens RVF, Khoo TL, Kondev FG, Lane GJ, Liu Z, Seweryniak D, Thompson NJ, Zhu S, Williams SJ (2007) Identification of a high-spin isomer in (99)Mo,PHYSICAL REVIEW C76(4)ARTN 047303 AMER PHYSICAL SOC
Britton R, Burnett J, Davies A, Regan PH (2012) Preliminary simulations of NaI(Tl) detectors, and coincidence analysis using event stamping, Journal of Radioanalytical and Nuclear Chemistrypp. 1-5 Springer
This paper discusses preliminary work into the modelling and processing of coincidence measurements, for which a Monte-Carlo simulation and a post-processing program have both been developed. In the current work, a GEANT4 code is used to simulate a pair of NaI(Tl) scintillators, which are used experimentally to both develop the post-processing program and validate the GEANT4 model. This is found to be accurate to within 9% at a confidence level of 93.0% for energies from 30 to 3,000 keV.
Mineva MN, Hellström M, Bernas M, Gerl J, Grawe H, Pfützner M, Regan PH, Rejmund M, Rudolph D, Becker F, Bingham CR, Enqvist T, Fogelberg B, Gausemel H, Geissel H, Genevey J, Górska M, Grzywacz R, Hauschild K, Janas Z, Kojouharov I, Kopatch Y, Korgul A, Korten W, Kurcewicz J, Lewitowicz M, Lucas R, Mach H, Mandal S, Mayet P, Mazzocchi C, Pinston JA, Podolyàk Z, Schaffner H, Schlegel C, Schmidt K, Sümmerer K, Wollersheim HJ (2001) A new ¼s isomer in 136Sb produced in the projectile fission of 238U, European Physical Journal A11(1)pp. 9-13
The neutron-rich isotope 136Sb has been produced following the relativistic projectile fission of 238U in an experiment performed at the Fragment Separator at GSI, Darmstadt. Delayed ³-ray spectroscopy of the fission products has been performed after isotope separation. A new isomeric state in 136Sb has been populated, and its lifetime measured as T1/2 = 565(50) ns. Realistic and empirical shell-model calculations have been performed and are compared to the experimental observables.
Bell SJ, Judge SM, Regan PH (2012) An investigation of HPGe gamma efficiency calibration software (ANGLE V.3) for applications in nuclear decommissioning., Appl Radiat Isot70(12)pp. 2737-2741
High resolution gamma spectrometry offers a rapid method to characterise waste materials on a decommissioning nuclear site. To meet regulatory requirements, measurements must be traceable to national standards, meaning that the spectrometers must be calibrated for a wide range of materials. Semi-empirical modelling software (such as ANGLE") offers a convenient method to carry out such calibrations. This paper describes an assessment of the modelling software for use by a small laboratory based on a nuclear site. The results confirmed the need for accurate information on the detection construction if the calibration were to be accurate to within 10%.
Gorska M, Grawe H, Caceres L, Algora A, Boehmer M, Boutachkov P, Eppinger K, Faestermann T, Fujita Y, Gadea A, Garnsworthy A, Gelletly W, Gerl J, Gernhaeuser R, Hinke C, Jungclaus A, Kojouharov I, Kruecken R, Maier L, Molina P, Pfuetzner M, Pietri S, Podolyak Z, Regan PH, Rubio B, Rudolph D, Wollersheim HJ (2009) NUCLEAR STRUCTURE ADDRESSED AT GSI/RISING, INTERNATIONAL JOURNAL OF MODERN PHYSICS E-NUCLEAR PHYSICS18(4)pp. 759-766 WORLD SCIENTIFIC PUBL CO PTE LTD
© 2015 Elsevier Ltd. Precision measurements of electromagnetic (EM) transition rates enable tests of models of internal nuclear structure. Measurements of transition rates can be used to infer the spin and parity differences between the initial and final discrete nuclear excited states via which the EM transition takes place. This short conference paper reports on developments of detection systems for the identification of discrete energy gamma-ray decays using arrays of halide-scintillation detectors acting in coincidence mode, which can be used to determine electromagnetic transition rates between excited nuclear states in the sub-nanosecond temporal regime. Ongoing development of a new multi-detector LaBr3(Ce) array for studies of exotic nuclei produced at the upcoming Facility for Anti-Proton and Ion Research (FAIR) as part of the NUSTAR-DESPEC project are presented, together with initial results from pre-NUSTAR implementations of this array for nuclear structure studies of neutron-rich fission fragment radionuclides at ILL-Grenoble, France and RIBF at RIKEN, Japan.
Steer SJ, Podolyak Z, Pietri S, Regan PH, Rudolph D, Werner-Malento E, Garnsworthy AB, Hoischen R, Gorska M, Gerl J, Wollersheim HJ, Becker F, Bednarczyk P, Caceres L, Doornenbal P, Geissel H, Grebosz J, Kelic A, Kurz N, Montes F, Prokopowicz W, Saito T, Schaffner H, Tachenov S, Heinz A, Pfuetzner M, Kurtukian-Nieto T, Benzoni G, Jungclaus A, Balabanski DL, Brandau C, Bruce AM, Catford WN, Cullen IJ, Dombradi Z, Estevez E, Gelletly W, Ilie G, Jolie J, Jones GA, Kmiecik M, Kondev FG, Lalkovski S, Liu Z, Maj A, Myalski S, Shizuma T, Schwertel S, Walker PM, Wieland O (2007) Identification of isomeric states 'south' of Pb-208 via projectile fragmentation, ACTA PHYSICA POLONICA B38(4)pp. 1283-1286 ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS
Myalski S, Kmiecik M, Maj A, Regan PH, Garnsworthy AB, Pietri S, Rudolph D, Podolyak Z, Steer SJ, Becker F, Bednarczyk P, Gerl J, Gorska M, Grawe H, Kojouharov I, Schaffner H, Wollersheim HJ, Prokopowicz W, Grebosz J, Benzoni G, Blank B, Brandau C, Bruce AM, Caceres L, Camera F, Catford WN, Cullen IJ, Dombradi Z, Doornenbal P, Estevez E, Geissel H, Gelletly W, Heinz A, Hoischen R, Ilie G, Jones GA, Jungclaus A, Kelic A, Kondev FG, Kurtukian-Nieto T, Kurz N, Lalkovski S, Liu Z, Montes F, Pfuetzner M, Saito T, Shizuma T, Simons AJ, Schwertel S, Tachenov S, Walker PM, Werner-Malento E, Wieland O (2007) Isomeric ratio for the I-pi=8(+) yrast state in Pd-96 produced in the relativistic fragmentation of Ag-107, ACTA PHYSICA POLONICA B38(4)pp. 1277-1282 ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS
Podolyak Z, Gerl J, Hellstroem M, Becker F, Gladnishki KA, Gorska M, Kelic A, Kopatch Y, Mandal S, Regan PH, Schmidt K-H, Walker PM, Wollersheim HJ, Banu A, Benzoni G, Boardman H, Casarejos E, Ekman J, Geissel H, Grawe H, Hohn D, Kojouharov I, Leske J, Lozeva R, Mineva MN, Neyens G, Page RD, Pearson CJ, Portillo M, Rudolph D, Saito N, Schaffner H, Sohler D, Summerer K, Valiente-Dobon JJ, Wheldon C, Weick H, Winkler M (2006) Neutron-deficient N approximate to 126 nuclei produced in U-238 fragmentation: Population of high-spin states,Frontiers in Nuclear Structure Astrophysics, and Reactions: FINUSTAR831pp. 114-118 AMER INST PHYSICS
Al-Sulaiti H, Regan PH, Bradley DA, Malain D, Santawamaitre T, Habib A, Matthews M, Bukhari S, Al-Dosari M (2010) A preliminary report on the determination of natural radioactivity levels of the State of Qatar using high-resolution gamma-ray spectrometry, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT619(1-3)pp. 427-431 ELSEVIER SCIENCE BV
Walker PM, Cullen DM, Purry CS, Appelbe DE, Byrne AP, Dracoulis GD, Kibedi T, Kondev FG, Lee LY, Macchiavelli AO, Reed AT, Regan PH, Xu F (1997) K-forbidden transitions from multi-quasiparticle states, PHYSICS LETTERS B408(1-4)pp. 42-46 ELSEVIER SCIENCE BV
Mason PJR, Alharbi T, Regan PH, Marginean N, Podolyak Z, Alkhomashi N, Bender PC, Bowry M, Bostan M, Bucurescu D, Bruce AM, Cata-Danil G, Cata-Danil I, Chakrabarti R, Deleanu D, Detistov P, Erduran MN, Filipescu D, Garg U, Glodariu T, Ghita D, Ghugre SS, Kusoglu A, Marginean R, Mihai C, Nakhostin M, Negret A, Pascu S, Triguero CR, Sava T, Simpson EC, Sinha AK, Stroe L, Suliman G, Zamfir NV (2012) Half-life of the I-pi=4(-) Intruder State in P-34 Using LaBr3:Ce Fast Timing, RUTHERFORD CENTENNIAL CONFERENCE ON NUCLEAR PHYSICS, 2011381 IOP PUBLISHING LTD
Bentley MA, Williams SJ, Joss DT, O'Leary CD, Bruce AM, Frankland L, Cameron JA, Svensson CE, Carpenter MP, Lister CJ, Reiter R, Seweryniak D, Fallon P, Gelletly W, Regan PH, Martinez-Pinedo G, Poves A, Solano JS, Rubio B, Warner DD (2002) Mirror symmetry and coulomb energies at high angular momentum, REVISTA MEXICANA DE FISICA48pp. 123-128 SOCIEDAD MEXICANA DE FISICA
Al-Garni S, Walker PM, Regan PH, Narro JG, El-Masri HM, Roeckl E, Kirchner R, La Commara M, Mazzocchi C, Grawe H, Borcea R, Doring J, Wooding SC, Schmidt K, Wheldon C, Cullen DM, Schmidt-Ott WD (2002) Evidence for a K approximate to.139/2 beta-decaying isomer in Lu-177, NUCLEAR PHYSICS IN THE 21ST CENTURY610pp. 854-858 AMER INST PHYSICS
Gottardo A, Valiente-Dobón JJ, Benzoni G, Nicolini R, Núñez JA, Algora A, Al-Dahan N, Angelis GD, Ayyad Y, Alkhomashi N, Allegro PRP, Benlliure J, Boutachkov P, Bowry M, Bracco A, Bruce AM, Bunce M, Casarejos E, Cortes L, Crespi FCL, Camera F, Corsi A, Bacelar AMD, Deo A, Domingo-Pardo C, Doncel M, Dombradi Z, Engert T, Eppinger K, Farrelly GF, Farinon F, Gadea A, Geissel H, Gerl J, Goel N, Górska M, Grebosz J, Gregor E, Haberman T, Hoischen R, Janik R, Klupp S, Kojouharov I, Kurz N, Leoni S, Lunardi S, Mandal S, Menegazzo R, Mengoni D, Million B, Napoli DR, Naqvi F, Nociforo C, Pfützner M, Pietri S, Podolyak Z, Prochazka A, Prokopowicz W, Recchia F, Ribas RV, Reed MW, Regan PH, Rudolph D, Sahin E, Schaffner H, Sharma A, Sitar B, Siwal D, Steger K, Strmen P, Swan TPD, Szarka I, Walker PM, Wieland O, Weick H, Wollersheim H-J (2011) Isomers in neutron-rich lead isotopes populated via the fragmentation of 238U at 1 GeV A,Journal of Physics: Conference Series: International Nuclear Physics Conference312(Section 9) Institute of Physics
Neutron-rich nuclei beyond N = 126 in the lead region were populated by
fragmenting a 238U beam at 1 GeV A on a Be target and then separated by the Fragment
Separator (FRS) at GSI. Their isomeric decays were observed, enabling study of the shell
structure of neutron-rich nuclei around the Z=82 shell closure. Some preliminary results are
reported in this paper.
Oi M, Regan PH, Xu FR, Walker PM, Rath AK, Stevenson PD (2002) Cranked-Hartree-Fock-Bogoliubov analysis at the valence maximum: Yrast behaviour of Dy-170(66)104, PROGRESS OF THEORETICAL PHYSICS SUPPLEMENT(146)pp. 609-610 PROGRESS THEORETICAL PHYSICS PUBLICATION OFFICE
Grieser M, Litvinov YA, Raabe R, Blaum K, Blumenfeld Y, Butler PA, Wenander F, Woods PJ, Aliotta M, Andreyev A, Artemyev A, Atanasov D, Aumann T, Balabanski D, Barzakh A, Batist L, Bernardes AP, Bernhardt D, Billowes J, Bishop S, Borge M, Borzov I, Bosch F, Boston AJ, Brandau C, Catford W, Catherall R, Cederkäll J, Cullen D, Davinson T, Dillmann I, Dimopoulou C, Dracoulis G, Düllmann CE, Egelhof P, Estrade A, Fischer D, Flanagan K, Fraile L, Fraser MA, Freeman SJ, Geissel H, Gerl J, Greenlees P, Grisenti RE, Habs D, von Hahn R, Hagmann S, Hausmann M, He JJ, Heil M, Huyse M, Jenkins D, Jokinen A, Jonson B, Joss DT, Kadi Y, Kalantar-Nayestanaki N, Kay BP, Kiselev O, Kluge HJ, Kowalska M, Kozhuharov C, Kreim S, Kröll T, Kurcewicz J, Labiche M, Lemmon RC, Lestinsky M, Lotay G, Ma XW, Marta M, Meng J, Mücher D, Mukha I, Müller A, Murphy AS, Neyens G, Nilsson T, Nociforo C, Nörtershäuser W, Page RD, Pasini M, Petridis N, Pietralla N, Pfützner M (2012) Storage ring at HIE-ISOLDE: Technical design report: Technical design report,European Physical Journal: Special Topics207(1)pp. 1-117 We propose to install a storage ring at an ISOL-type radioactive beam facility for the first time. Specifically, we intend to setup the heavy-ion, low-energy ring TSR at the HIE-ISOLDE facility in CERN, Geneva. Such a facility will provide a capability for experiments with stored secondary beams that is unique in the world. The envisaged physics programme is rich and varied, spanning from investigations of nuclear ground-state properties and reaction studies of astrophysical relevance, to investigations with highly-charged ions and pure isomeric beams. The TSR might also be employed for removal of isobaric contaminants from stored ion beams and for systematic studies within the neutrino beam programme. In addition to experiments performed using beams recirculating within the ring, cooled beams can also be extracted and exploited by external spectrometers for high-precision measurements. The existing TSR, which is presently in operation at the Max-Planck Institute for Nuclear Physics in Heidelberg, is well-suited and can be employed for this purpose. The physics cases as well as technical details of the existing ring facility and of the beam and infrastructure requirements at HIE-ISOLDE are discussed in the present technical design report. © 2012 EDP Sciences and Springer.
Chandler C, Regan PH, Blank B, Pearson CJ, Bruce AM, Catford WN, Curtis N, Czajkowski S, Dessagne P, Fleury A, Gelletly W, Giovinazzo J, Grzywacz R, Janas Z, Lewitowicz M, Marchand C, Miehe C, Orr NA, Page RD, Pravikoff MS, Reed AT, Saint-Laurent MG, Vincent SM, Wadsworth R, Warner DD, Winfield JS, Xu F (2000) Observation of isomeric states in neutron deficient A similar to 80 nuclei following the projectile fragmentation of Mo-92, PHYSICAL REVIEW C61(4)ARTN 044309 AMERICAN PHYSICAL SOC
Al-Sulaiti L, Shipley D, Thomas R, Owen P, Kacperek A, Regan PH, Palmans H (2012) Water equivalence of some plastic-water phantom materials for clinical proton beam dosimetry, Applied Radiation and Isotopes70(7)pp. 1052-1057
Plastic-water phantom materials are not exactly water equivalent since they have a different elemental composition and different interaction cross sections for protons than water. Several studies of the water equivalence of plastic-water phantom materials have been reported for photon and electron beams, but none for clinical proton beams. In proton beams, the difference between non-elastic nuclear interactions in plastic-water phantom materials compared to those in water should be considered. In this work, the water equivalence of Plastic Water ® (PW) 1, Plastic Water ® Diagnostic Therapy (PWDT) 1 and solid water (WT1) 2 phantoms was studied for clinical proton energies of 60MeV and 200MeV. This was done by evaluating the fluence correction factor at equivalent depths; first with respect to water and then with respect to graphite by experiment and Monte Carlo (MC) simulations using FLUKA. MC simulations showed that the fluence correction with respect to water was less than 0.5% up to the entire penetration depth of the protons at 60MeV and less than 1% at 200MeV up to 20cm depth for PWDT, PW and WT1. With respect to graphite the fluence correction was about 0.5% for 60MeV and about 4% for 200MeV. The experimental results for modulated and un-modulated 60MeV proton beams showed good agreement with the MC simulated fluence correction factors with respect to graphite deviating less than 1% from unity for the three plastic-water phantoms. © 2012 Elsevier Ltd.
Goerska M, Banu A, Bednarczyk P, Bracco A, Buerger A, Camera F, Caurier E, Doornenbal P, Gerl J, Grawe H, Honma M, Huebel H, Jungclaus A, Maj A, Neyens G, Nowacki F, Otsuka T, Pfutzner T, Pietri S, Podolyak Z, Poves A, Regan PH, Reiter P, Rudolph D, Wollersheim HJ (2007) Nuclear structure far off stability - Rising campaigns, ACTA PHYSICA POLONICA B38(4)pp. 1219-1228 ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS
Kumar R, Molina FG, Pietri S, Casarejos E, Algora A, Benlliure J, Doornenbal P, Gerl J, Gorska M, Kojouharov I, Podolyak Z, Prokopowicz W, Regan PH, Rubio B, Schaffner H, Tashenov S, Wollersheim H-J (2009) Testing of a DSSSD detector for the stopped RISING project, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT598(3)pp. 754-758 ELSEVIER SCIENCE BV
Mohammadi S, De Angelis G, Axiotis M, Bazzacco D, Bizzeti PG, Brandolini F, Broda R, Bucurescu D, Farnea E, Gelletly W, Gadea A, Ionescu-Bujor M, Iordachescu A, Kroll T, Longdown S, Lunardi S, Marginean N, Martinez T, Medina N, Podolyak Z, Quintana B, Regan PH, Rubio B, Ur CA, Dobon J-JV, Walker PM, Zhang YH (2006) Yrast states in Os-188,Os-190 nuclei, INTERNATIONAL JOURNAL OF MODERN PHYSICS E-NUCLEAR PHYSICS15(8)pp. 1797-1802 WORLD SCIENTIFIC PUBL CO PTE LTD
Garnsworthy AB, Regan PH, Cáceres L, Pietri S, Sun Y, Rudolph D, Górska M, Podolyák Z, Steer SJ, Hoischen R, Heinz A, Becker F, Bednarczyk P, Doornenbal P, Geissel H, Gerl J, Grawe H, Gr)bosz J, Kelic A, Kojouharov I, Kurz N, Montes F, Prokopowicz W, Saito T, Schaffner H, Tachenov S, Werner-Malento E, Wollersheim HJ, Benzoni G, Blank BB, Brandau C, Bruce AM, Camera F, Catford WN, Cullen IJ, Dombrádi Z, Estevez E, Gelletly W, Ilie G, Jolie J, Jones GA, Jungclaus A, Kmiecik M, Kondev FG, Kurtukian-Nieto T, Lalkovski S, Liu Z, Maj A, Myalski S, Pfützner M, Schwertel S, Shizuma T, Simons AJ, Walker PM, Wieland O, Xu FR (2008) Erratum to: "Neutron-proton pairing competition in N = Z nuclei: Metastable state decays in the proton dripline nuclei 82 41Nb and 86 43Tc", Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics668(5)pp. 460-460
Saitoh TR, Saitoh-Hashimoto N, Sletten G, Bark RA, Bergstrom M, Regan P, Tormanen S, Varmette PG, Walker PM (1999) Collective and intrinsic structures in W-183, NUCLEAR PHYSICS A660(2)pp. 171-196 ELSEVIER SCIENCE BV
Georgiev G, Neyens G, Hass M, Balabanski DL, Bingham C, Borcea C, Coulier N, Coussement R, Daugas JM, De France G, Santos FD, Gorska M, Grawe H, Grzywacz R, Lewitowicz M, Mach H, Matea I, Page RD, Pfutzner M, Penionzhkevich YE, Podolyak Z, Regan PH, Rykaczewski K, Sawicka M, Smirnova NA, Sobolev YG, Stanoiu M, Teughels S, Vyvey K (2002) g factor measurements of mu s isomeric states in neutron-rich nuclei around Ni-68 produced in projectile-fragmentation reactions, JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS28(12)PII S0954-3899(02)54753-8pp. 2993-3006 IOP PUBLISHING LTD
Shand CM, Wilson E, Podolyák Z, Grawe H, Brown BA, Fornal B, Janssens RVF, Bowry M, Bunce M, Carpenter MP, Carroll RJ, Chiara CJ, Cieplicka-OryDczak N, Deo AY, Dracoulis GD, Hoffman CR, Kempley RS, Kondev FG, Lane GJ, Lauritsen T, Lotay G, Reed MW, Regan PH, Rodriguez-Triguero C, Seweryniak D, Szpak B, Walker PM, Zhu S (2015) Structure of <sup>207</sup>Pb populated in <sup>208</sup>Pb + <sup>208</sup>Pb deep-inelastic collisions, Acta Physica Polonica B46(3)pp. 619-622
The yrast structure of 207Pb above the 13=2+ isomeric state has been investigated in deep-inelastic collisions of 208Pb and 208Pb at ATLAS, Argonne National Laboratory. New and previously observed transitions were measured using the Gammasphere detector array. The level scheme of 207Pb is presented up to < 6 MeV, built using coincidence and ³-ray intensity analyses. Spin and parity assignments of states were made, based on angular distributions and comparisons to shell model calculations.
Rice S, Valencia E, Algora A, Tain JL, Regan PH, Podolyak Z, Agramunt J, Gelletly W, Nichols AL (2012) Decay Heat Measurements Using Total Absorption Gamma-ray Spectroscopy, RUTHERFORD CENTENNIAL CONFERENCE ON NUCLEAR PHYSICS, 2011381 IOP PUBLISHING LTD
Jones GA, Walker PM, Podoydk Z, Regan PH, Williams SJ, Carpentert MP, Carroll JJ, Chakrawarthy RS, Chowdhury P, Cullen IJ, Dracoulis GD, Gamsworthy AB, Hackman G, Janssens RVF, Khoo TL, Kondev FG, Lane GJ, Liu Z, Seweryniak D, Thompson NJ, Zhu S (2006) Microsecond and nanosecond isomers populated in fission reactions, FUSION06: Reaction Mechanisms and Nuclear Structure at the Coulomb Barrier853pp. 342-349 AMER INST PHYSICS
Al-Sulaiti H, Nasir T, Regan PH, Bradley D, Al-Mugren K, Alkhomashi N, Al-Dahan N, Al-Dosari M, Bukhari SJ, Matthews M, Santawamaitre T, Malain D, Habib A (2014) Effect of the grain size of the soil on the measured activity and variation in activity in surface and subsurface soil samples,Pakistan Journal of Scientific and Industrial Research Series A: Physical Sciences57(3)pp. 129-138 Correlation between grain size and activity concentrations of soils and concentrations of various radionuclides in surface and subsurface soils has been measured for samples taken in the State of Qatar by gamma-spectroscopy using a high purity germanium detector. From the obtained gamma-ray spectra, the activity concentrations of the 238U (226Ra) and 232Th (228Ac) natural decay series, the long-lived naturally occurring radionuclide 40K and the fission product radionuclide 137Cs have been determined. Gamma dose rate, radium equivalent, radiation hazard index and annual effective dose rates have also been estimated from these data. In order to observe the effect of grain size on the radioactivity of soil, three grain sizes were used i.e., smaller than 0.5 mm; smaller than 1 mm and greater than 0.5 mm; and smaller than 2 mm and greater than 1 mm. The weighted activity concentrations of the 238U series nuclides in 0.5-2 mm grain size of sample numbers was found to vary from 2.5±0.2 to 28.5±0.5 Bq/kg, whereas, the weighted activity concentration of 40 K varied from 21±4 to 188±10 Bq/kg. The weighted activity concentrations of 238U series and 40 K have been found to be higher in the finest grain size. However, for the 232Th series, the activity concentrations in the 1-2 mm grain size of one sample were found to be higher than in the 0.5-1 mm grain size. In the study of surface and subsurface soil samples, the activity concentration levels of 238 U series have been found to range from 15.9±0.3 to 24.1±0.9 Bq/kg, in the surface soil samples (0-5 cm) and 14.5±0.3 to 23.6±0.5 Bq/kg in the subsurface soil samples (5-25 cm). The activity concen- trations of 232Th series have been found to lie in the range 5.7±0.2 to 13.7±0.5 Bq/kg, in the surface soil samples (0-5 cm) and 4.1±0.2 to 15.6±0.3 Bq/kg in the subsurface soil samples (5-25 cm). The activity concentrations of 40K were in the range 150±8 to 290±17 Bq/kg, in the surface soil samples (0-5 cm) and 129±7 to 299±14 Bq/kg, in the subsurface soil samples (5-25 cm). The activity concentrations of 238U series, 232Th series and 40K in the surface and deep soil samples are approximately same. The 137Cs activity concentration levels in surface soil samples in four sites were found to be higher than those observed for the soil samples that been collected at a depth of 5-25 cm. They ranged from 1.65±0.22 to 19.0±0.9 Bq/kg, in the surface soil samples (0-5 cm) and 0.5±0.2 to 15.4±0.7 Bq/kg, in the subsurface soil samples (5-25 cm).
Tarifeno-Saldivia A, Tain J, Domingo-Pardo C, Calvino F, Cortes G, Phong V, Riego A, Agramunt J, Algora A, Brewer N, Caballero-Folch R, Coleman-Smith P, Davinson T, Dillmann I, Estrade A, Griffin C, Grzywacz R, Harkness-Brennan L, Kiss G, Kogimtzis M, Lazarus I, Lorusso G, Matsui K, Miernik K, Montes F, Morales A, Nishimura S, Page R, Podolyak Z, Pucknell V, Rasco B, Regan P, Rubio P, Rykaczewski K, Sakurai H, Simpson J, Sokol E, Surman R, Svirkhin A, Thomas S, Tolosa A, Woods P (2017) Conceptual design of a hybrid neutron-gamma detector for study of -delayed neutrons at the RIB facility of RIKEN,Journal of Instrumentation12 Institute of Physics
The conceptual design of the BRIKEN neutron detector at the radioactive ion beam factory (RIBF) of the RIKEN Nishina Center is reported. The BRIKEN setup is a complex system aimed at detecting heavy-ion implants, ² particles, ³ rays and ²-delayed neutrons. The whole setup includes the Advanced Implantation Detection Array (AIDA), two HPGe Clover detectors and up to 166 3He-filled counters embedded in a high-density polyethylene moderator. The design is quite complex due to the large number and different types of 3He-tubes involved and the additional constraints introduced by the ancillary detectors for charged particles and ³ rays. This article reports on a novel methodology developed for the conceptual design and optimisation of the 3He-counter array, aiming for the best possible performance in terms of neutron detection. The algorithm is based on a geometric representation of two selected detector parameters of merit, namely, the average neutron detection efficiency and the efficiency flatness as a function of a reduced number of geometric variables. The response of the neutron detector is obtained from a systematic Monte Carlo simulation implemented in Geant4. The robustness of the algorithm allowed us to design a versatile detection system, which operated in hybrid mode includes the full neutron counter and two clover detectors for high-precision gamma spectroscopy. In addition, the system can be reconfigured into a compact mode by removing the clover detectors and re-arranging the 3He tubes in order to maximize the neutron detection performance. Both operation modes shows a rather flat and high average efficiency. In summary, we have designed a system which shows an average efficiency for hybrid mode (3He tubes + clovers) of 68.6% and 64% for neutron energies up to 1 and 5 MeV, respectively. For compact mode (only 3He tubes), the average efficiency is 75.7% and 71% for neutron energies up to 1 and 5 MeV, respectively. The performance of the BRIKEN detection system has been also quantified by means of Monte Carlo simulations with different neutron energy distributions.
Wheldon C, Narro JG, Pearson CJ, Regan PH, Podolyak Z, Warner DD, Fallon P, Macchiavelli AO, Cromaz M (2001) Yrast states in Os-194: The prolate-oblate transition region, PHYSICAL REVIEW C63(1)ARTN 011304 AMERICAN PHYSICAL SOC
Andgren K, Ashley SF, Regan PH, McCutchan EA, Zamfir NV, Amon L, Cakirli RB, Casten RF, Clark RM, Erduran MN, Gürdal G, Keyes KL, Meyer DA, Papenberg A, Pietralla N, Plettner C, Rainovski G, Ribas RV, Thomas NJ, Vinson J, Warner DD, Werner V, Williams E (2006) Recoil distance method lifetime measurements in 107Cd and 103Pd, AIP Conference Proceedings831pp. 391-393
Preliminary lifetime values have been measured for a number of near-yrast states in the odd-A transitional nuclei 107Cd and 103Pd. The reaction used to populate the nuclei of interest was 98Mo( 12C,3nx±)107Cd, 103Pd, with the beam delivered by the tandem accelerator of the Wright Nuclear Structure Laboratory at an incident beam energy of 60 MeV. Our experiment was aimed at the investigation of collective excitations built on the unnatural parity, ½ h11/2 orbital, specifically by measuring the B(E2) values of decays from the excited levels built on this intrinsic structure, using the Doppler Recoil Distance Method. We report lifetimes and associated transition probabilities for decays from the 15/2- and the 19/2- states in 107Cd and the first measurement of the 15/2- state in 103Pd. These results suggest that neither a simple rotational or vibrational interpretation is sufficient to explain the observed structures. © 2006 American Institute of Physics.
Bunce M, Regan PH, Werner V, Beausang CW, Anagnostatou V, Bowry M, Casperson RJ, Chen D, Cooper N, Goddard PM, Hughes RO, Ilie G, Mason PJR, Pauerstein B, Reed MW, Ross TJ, Simpson EC (2013) High-spin study of the shell model nucleus 88Y49, Physical Review C - Nuclear Physics87(4)
The near-yrast structure of the near-magic, odd-odd nucleus, 3988Y 49, has been studied into the high-spin regime. Investigations were performed at the Wright Nuclear Structure Laboratory, Yale University, using the 74Ge(18O,p3n) and 76Ge(18O,p5n) fusion-evaporation reactions at beam energies of 60 and 90 MeV, respectively. Gamma-ray energy coincidence analyses using both double (³2) and triple (³3) fold coincidences, together with angular correlation measurements, have been used to extend the previously reported level scheme to an excitation energy of 8.6 MeV and a spin and parity of 19(-). The presented level scheme is compared with predictions of a truncated valence space shell-model calculation, which assumes an inert 56Ni core with proton and neutron excitations allowed within the f5/2, p3/2, p1/2, and g 9/2 single-particle states. The shell-model calculations show a reasonable comparison with the experimental data for the yrast, positive-parity states up to spin 18 â, with larger variations evident for negative-parity states with spins greater than 16. In spite of a significant increase in angular momentum input associated with the thin target 76Ge(18O,p5n) reaction channel, as compared to the backed target data using the 74Ge target, no additional discrete states were identified in the former data set, suggesting that the level scheme for this nucleus fragments significantly above the observed states, possibly indicating cross-shell excitations becoming dominant for I>19. © 2013 American Physical Society.
Bruce AM, Lalkovski S, Bacelar AMD, Gorska M, Pietri S, Podolyak Z, Shi Y, Walker PM, Xu FR, Bednarczyk P, Caceres L, Casarejos E, Cullen IJ, Doornenbal P, Farrelly GF, Garnsworthy AB, Geissel H, Gelletly W, Gerl J, Grebosz J, Hinke C, Ilie G, Jaworski G, Kojouharov I, Kurz N, Myalski S, Palacz M, Prokopowicz W, Regan PH, Schaffner H, Steer S, Tashenov S, Wollersheim HJ (2010) Shape coexistence and isomeric states in neutron-rich Tc-112 and Tc-113,PHYSICAL REVIEW C82(4)ARTN 044312 AMER PHYSICAL SOC
Caamãno M, Walker PM, Regan PH, Pearson CJ, Podolyak ZS, Mayet P, Gerl J, Schlegel C, Hellström M, Mlneva M, Pfützner M (2001) Isomeric decays in200Pt, Acta Physica Polonica B32(3)pp. 763-766
A projectile fragmentation experiment has been performed to populate the neutron-rich A < 190 mass region, approaching the Z = 82, N = 126 closed shell. A previously unreported isomer is found in 200Pt, being the first new example, from fragmentation reactions, of a seniority 4 state established from ³-³ coincidences.
Britton R, Regan PH, Burnett JL, Davies AV (2014) Next Generation Detection Systems for Radioactive Material Analysis, NUCLEAR DATA SHEETS119pp. E410-E412 ACADEMIC PRESS INC ELSEVIER SCIENCE
Reed AT, Tarasov O, Page RD, Guillemaud-Mueller D, Penionzhkevich YE, Allatt RG, Angelique JC, Anne R, Borcea C, Burjan V, Catford WN, Dlouhy Z, Donzaud C, Grevy S, Lewitowicz M, Lukyanov SM, Marques FM, Martinez G, Mueller AC, Nolan PJ, Novak J, Orr NA, Pougheon F, Regan PH, Saint-Laurent MG, Siiskonen T, Sokol E, Sorlin O, Suhonen J, Trinder W, Vincent SM (1999) Radioactivity of neutron-rich oxygen, fluorine, and neon isotopes, PHYSICAL REVIEW C60(2)ARTN 024311 AMERICAN PHYSICAL SOC
Pearson CJ, Dobon JJV, Regan PH, Sellin PJ, Morton E, Nolan PJ, Boston A, Descovich M, Thornhill J, Cresswell J, Lazarus I, Simpson J (2002) Digital gamma-ray tracking algorithms in segmented germanium detectors, IEEE TRANSACTIONS ON NUCLEAR SCIENCE49(3)pp. 1209-1215 IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Morales AI, Benzoni G, Gottardo A, Valiente-Dobón JJ, Blasi N, Bracco A, Camera F, Crespi FCL, Corsi A, Leoni S, Million B, Nicolini R, Wieland O, Gadea A, Lunardi S, Górska M, Regan PH, Podolyák Z, Pfützner M, Pietri S, Boutachkov P, Weick H, Grebosz J, Bruce AM, Núñez JA, Algora A, Al-Dahan N, Ayyad Y, Alkhomashi N, Allegro PRP, Bazzacco D, Benlliure J, Bowry M, Bunce M, Casarejos E, Cortes ML, Bacelar AMD, Deo AY, De Angelis G, Domingo-Pardo C, Doncel M, Dombradi Z, Engert T, Eppinger K, Farrelly GF, Farinon F, Farnea E, Geissel H, Gerl J, Goel N, Gregor E, Habermann T, Hoischen R, Janik R, Klupp S, Kojouharov I, Kurz N, Mandal S, Menegazzo R, Mengoni D, Napoli DR, Naqvi F, Nociforo C, Prochazka A, Prokopowicz W, Recchia F, Ribas RV, Reed MW, Rudolph D, Sahin E, Schaffner H, Sharma A, Sitar B, Siwal D, Steiger K, Strmen P, Swan TPD, Szarka I, Ur CA, Walker PM, Wollersheim HJ (2014) ² -decay studies of neutron-rich Tl, Pb, and Bi isotopes,Physical Review C - Nuclear Physics89(1) The fragmentation of relativistic uranium projectiles has been exploited at the Gesellschaft für Schwerionenforschung laboratory to investigate the ² decay of neutron-rich nuclei just beyond 208Pb. This paper reports on ²-delayed ³ decays of 211-213Tl, 215Pb, and 215-219Bi de-exciting states in the daughters 211-213Pb, 215Bi, and 215-219Po. The resulting partial level schemes, proposed with the help of systematics and shell-model calculations, are presented. The role of allowed Gamow-Teller and first-forbidden ² transitions in this mass region is discussed. © 2014 American Physical Society.
Morales AI, Benlliure J, Regan PH, Podolyak Z, Gorska M, Alkhomashi N, Pietri S, Kumar R, Casarejos E, Agramunt J, Algora A, Alvarez-Pol H, Benzoni G, Blazhev A, Boutachkov P, Bruce AM, Caceres LS, Cullen IJ, Bacelar AMD, Doornenbal P, Dragosavac D, Estevez ME, Farrelly G, Fujita Y, Garnsworthy AB, Gelletly W, Gerl J, Grebosz J, Hoischen R, Kojouharov I, Kurz N, Lalkovski S, Liu Z, Perez-Loureiro D, Prokopowicz W, Mihai C, Molina F, Muecher D, Rubio B, Schapffner H, Steer SJ, Tamii A, Tashenov S, Dobon JJV, Verma S, Walker PM, Wollersheim HJ, Woods PJ (2009) beta-DELAYED gamma-RAY SPECTROSCOPY OF HEAVY NEUTRON RICH NUCLEI "SOUTH" OF LEAD,ACTA PHYSICA POLONICA B40(3)pp. 867-870 POLISH ACAD SCIENCES INST PHYSICS
Regis J-M, Jolie J, Saed-Samii N, Warr N, Pfeiffer M, Blanc A, Jentschel M, Koester U, Mutti P, Soldner T, Simpson GS, Drouet F, Vancraeyenest A, de France G, Clement E, Stezowski O, Ur CA, Urban W, Regan PH, Podolyak Z, Larijani C, Townsley C, Carroll R, Wilson E, Fraile LM, Mach H, Paziy V, Olaizola B, Vedia V, Bruce AM, Roberts OJ, Smith JF, Kroell T, Hartig A-L, Ignatov A, Ilieva S, Thuerauf M, Lalkovski S, Ivanova D, Kisyov S, Korten W, Salsac M-D, Zielinska M, Marginean N, Ghita DG, Lica R, Petrache CM, Astier A, Leguillon R (2014) B(E2; 2(1)(+) -> 0(1)(+)) value in Kr-90,PHYSICAL REVIEW C90(6)ARTN 06730 AMER PHYSICAL SOC
© 2014 American Physical Society.A smooth onset of collectivity in 88,92,94,96Kr has been determined from reported B(E2;21+01+) and E(21+) values. This is in contrast to the sudden onset in even-even Zr, Mo, and Sr isotopes. Our objective was to complete the systematics by determining the B(E2;21+01+) value in Kr90, which was produced by cold-neutron-induced fission of 235U. The lifetime of the 21+ state in Kr90 was measured via the electronic ³-³ timing technique using the EXILL and FATIMA spectrometers. Based on the measured mean lifetime of Ä = 15(10) ps, the B(E2;21+01+) value of 13-5+26 W.u. in Kr90 is determined for the first time and the smooth onset of deformation in the even-even Kr isotopes beyond neutron number N=50 is confirmed.
Jolie J, Régis JM, Wilmsen D, Ahmed S, Pfeiffer M, Saed-Samii N, Warr N, Blanc A, Jentschel M, Köster U, Mutti P, Soldner T, Simpson G, De France G, Urban W, Bruce AM, Roberts OJ, Fraile LM, Paziy V, Ignatov A, Ilieva S, Kröll T, Scheck M, Thürauf M, Ivanova D, Kisyov S, Lalkovski S, Podolyak Z, Regan PH, Korten W, Habs D, Thirolf PG, Ur CA (2014) First results of the (n,³) EXILL campaigns at the Institut Laue Langevin using EXOGAM and FATIMA,Journal of Physics: Conference Series533(1) At the PF1B cold neutron beam line at the Institut Laue Langevin the EXILL array consisting of EXOGAM, GASP and LOHENGRIN detectors was used to perform (n,³) measurements under very high coincidence rates. About ten different reactions were then measured in autumn 2012. In spring 2013 the EXOGAM array was combined with 16 LaBr3(Ce) scintillators in the FATIMA@EXILL campaign for the measurement of lifetimes using the generalised centroid difference method. We report on the properties of both set-ups and present first results on Pt isotopes from both campaigns.
Mandal S, Gerl J, Geissel H, Hauschild K, Hellstrom M, Janas Z, Kojouharov I, Kopatch Y, Lemmon RC, Mayet P, Podolyak Z, Regan PH, Schaffner H, Schlegel C, Simpson J, Wollersheim HJ (2001) Gamma-ray spectroscopy with relativistic exotic heavy-ions, PRAMANA-JOURNAL OF PHYSICS57(1)pp. 161-164 INDIAN ACADEMY SCIENCES
Pfutzner M, Regan PH, Walker PM, Podolyak Z, Caamano M, Gerl J, Hellstrom M, Mayet P, Mineva MN (2001) Population of high spin states in relativistic fragmentation, ACTA PHYSICA POLONICA B32(9)pp. 2507-2518 ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS
Zakari-Issoufou A-A, Fallot M, Porta A, Algora A, Tain JL, Valencia E, Rice S, Bui VM, Cormon S, Estienne M, Agramunt J, Aysto J, Bowry M, Briz JA, Caballero-Folch R, Cano-Ott D, Cucoanes A, Elomaa V-V, Eronen T, Estevez E, Farrelly GF, Garcia AR, Gelletly W, Gomez-Hornillos MB, Gorlychev V, Hakala J, Jokinen A, Jordan MD, Kankainen A, Karvonen P, Kolhinen VS, Kondev FG, Martinez T, Mendoza E, Molina F, Moore I, Perez-Cerdan AB, Podolyak Z, Penttila H, Regan PH, Reponen M, Rissanen J, Rubio B, Shiba T, Sonzogni AA, Weber C (2015) Total Absorption Spectroscopy Study of Rb-92 Decay: A Major Contributor to Reactor Antineutrino Spectrum Shape,PHYSICAL REVIEW LETTERS115(10)ARTN 10250 AMER PHYSICAL SOC
Podolyak Z, Gerl J, Hellstrom M, Becker F, Gladnishki KA, Gorska M, Kelic A, Kopatch Y, Mandal S, Regan PH, Schmidt KH, Walker PM, Wollersheim HJ, Banu A, Benzoni G, Boardman H, Casarejos E, Ekman J, Geissel H, Grawe H, Hohn D, Kojouharov I, Leske J, Lozeva R, Mineva MN, Neyens G, Page RD, Pearson CJ, Portillo M, Rudolph D, Saito N, Schaffner H, Sohler D, Summerer K, Valiente-Dobon JJ, Wheldon C, Weick H, Winkler M (2006) High angular momentum states populated in fragmentation reactions, PHYSICS LETTERS B632(2-3)pp. 203-206 ELSEVIER SCIENCE BV
Jerome SM, Ivanov P, Larijani C, Parker DJ, Regan PH (2014) The production of Neptunium-236g, Journal of Environmental Radioactivity138pp. 315-322
© 2014 Elsevier Ltd.Radiochemical analysis of 237Np is important in a number of fields, such as nuclear forensics, environmental analysis and measurements throughout the nuclear fuel cycle. However analysis is complicated by the lack of a stable isotope of neptunium. Although various tracers have been used, including 235Np, 239Np and even 236Pu, none are entirely satisfactory. However, 236gNp would be a better candidate for a neptunium yield tracer, as its long half-life means that it is useable as both a radiometric and mass spectrometric measurements. This radionuclide is notoriously difficult to prepare, and limited in scope. In this paper, we examine the options for the production of 236gNp, based on work carried out at NPL since 2011. However, this work was primarily aimed at the production of 236Pu, and not 236gNp and therefore the rate of production are based on the levels of 236Pu generated in the irradiation of (i) 238U with protons, (ii) 235U with deuterons, (iii) 236U with protons and (iv) 236U with deuterons. The derivation of a well-defined cross section is complicated by the relevant paucity of information on the variation of the 236mNp:236gNp production ratio with incident particle energy. Furthermore, information on the purity of 236gNp so produced is similarly sparse. Accordingly, the existing data is assessed and a plan for future work is presented.
Podolyak Z, Caamano M, Regan PH, Walker PM, Mayet P, Gerl J, Schlegel C, Hellstrom M, Mineva M, Pfutzner M (2002) Isomeric decays in neutron-rich W, Os and Pt nuclei, PROGRESS OF THEORETICAL PHYSICS SUPPLEMENT(146)pp. 467-472 PROGRESS THEORETICAL PHYSICS PUBLICATION OFFICE
Régis JM, Simpson GS, Blanc A, De France G, Jentschel M, Köster U, Mutti P, Paziy V, Saed-Samii N, Soldner T, Ur CA, Urban W, Bruce AM, Drouet F, Fraile LM, Ilieva S, Jolie J, Korten W, Kröll T, Lalkovski S, Mach H, MÎrginean N, Pascovici G, Podolyak Z, Regan PH, Roberts OJ, Smith JF, Townsley C, Vancraeyenest A, Warr N (2014) Germanium-gated ³-³ Fast timing of excited states in fission fragments using the EXILL&FATIMA spectrometer, Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment763pp. 210-220
A high-granularity mixed spectrometer consisting of high-resolution Ge and very fast LaBr3(Ce)-scintillator detectors has been installed around a fission target at the cold-neutron guide PF1B of the high-flux reactor of the Institut Laue-Langevin. Lifetimes of excited states in the range of 10 ps to 10 ns can be measured in around 100 exotic neutron-rich fission fragments using Ge-gated LaBr3(Ce)-LaBr3(Ce) or Ge-Ge-LaBr 3(Ce)-LaBr3(Ce) coincidences. We report on various characteristics of the EXILL&FATIMA spectrometer for the energy range of 40 keV up to 6.8 MeV and present results of ps-lifetime test measurements in a fission fragment. The results are discussed with respect to possible systematic errors induced by background contributions. © 2014 Published by Elsevier B.V.
Naqvi F, Gorska M, Caceres L, Jungclaus A, Pfuetzner M, Grawe H, Nowacki F, Sieja K, Pietri S, Werner-Malento E, Regan PH, Rudolf D, Podolyak Z, Jolie J, Andgren K, Beck T, Bednarczyk P, Benlliure J, Benzoni G, Bruce AM, Casarejos E, Cederwall B, Crespi FCL, Detistov P, Dombradi Z, Doornenbal P, Geissel H, Gerl J, Grebosz J, Hadinia B, Hellstrom M, Hoischen R, Ilie G, Khaplanov A, Kojouharov I, Kmiecik M, Kurz N, Lalkovski S, Maj A, Mandal S, Modamio V, Montes F, Myalski S, Prokopowicz W, Reiter P, Schaffner H, Simpson G, Sohler D, Steer SJ, Tashenov S, Walker J, Wieland O, Wollersheim HJ (2010) Isomer spectroscopy of Cd-127,PHYSICAL REVIEW C82(3)ARTN 034323 AMER PHYSICAL SOC
Rice S, Valencia E, Algora A, Taín JL, Regan PH, Podolyák Z, Agramunt J, Gelletly W, Nichols AL (2012) Decay heat measurements using total absorption gamma-ray spectroscopy, Journal of Physics: Conference Series381(1)
A knowledge of the decay heat emitted by thermal neutron-irradiated nuclear fuel is an important factor in ensuring safe reactor design and operation, spent fuel removal from the core, and subsequent storage prior to and after reprocessing, and waste disposal. Decay heat can be readily calculated from the nuclear decay properties of the fission products, actinides and their decay products as generated within the irradiated fuel. Much of the information comes from experiments performed with HPGe detectors, which often underestimate the beta feeding to states at high excitation energies. This inability to detect high-energy gamma emissions effectively results in the derivation of decay schemes that suffer from the pandemonium effect, although such a serious problem can be avoided through application of total absorption ³-ray spectroscopy (TAS). The beta decay of key radionuclei produced as a consequence of the neutron-induced fission of 235U and 239Pu are being re-assessed by means of this spectroscopic technique. A brief synopsis is given of the Valencia-Surrey (BaF 2) TAS detector, and their method of operation, calibration and spectral analysis. © Published under licence by IOP Publishing Ltd.
Nara Singh BS, Brock TS, Wadsworth R, Grawe H, Boutachkov P, Braun N, Blazhev A, Liu Z, Górska M, Pietri S, Rudolph D, Domingo-Pardo C, Steer SJ, Ataç A, Bettermann L, Cáceres L, Engert T, Faestermann T, Farinon F, Finke F, Geibel K, Gerl J, Gernhäuser R, Goel N, Gottardo A, Gr)bosz J, Hinke C, Hoischen R, Ilie G, Iwasaki H, Jolie J, Ka_ka_ A, Kojouharov I, Krücken R, Kurz N, Merchán E, Nociforo C, Nyberg J, Pfützner M, Prochazka A, Podolyák Z, Regan PH, Reiter P, Rinta-Antila S, Scholl C, Schaffner H, Söderström PA, Warr N, Weick H, Wollersheim HJ, Woods PJ, Nowacki F (2012) Influence of the np interaction on the ² decay of 94Pd, Physical Review C - Nuclear Physics86(4)
We present results from stopped beam rare isotope spectroscopic investigations at the GSI (RISING) experiment based on the detection of ³-ray transitions following the ² decay of 94Pd. A comparison between the measured low-lying level scheme of 94Rh and the prediction from shell-model calculations reveals the important roles of the g 7/2 and g 9/2 orbitals in explaining the structural features. The low values of the Gamow-Teller strengths B(GT) can be attributed to the influence of the neutron-proton interaction, which gives rise to an increased seniority mixing for the nuclear states, thereby leading to a fragmentation of the strength to several daughter levels. These results provide further strong indications that 94Pd resides in the middle of a structural transition region in the Pd isotopes as the N=Z line is approached. © 2012 American Physical Society.
Lazarus IH, Appelbe DE, Butler PA, Coleman-Smith PJ, Cresswell JR, Freeman SJ, Herzberg RD, Hibbert I, Joss DT, Letts SC, Page RD, Pucknell VFE, Regan PH, Sampson J, Simpson J, Thornhill J, Wadsworth R (2001) The GREAT triggerless total data readout method,IEEE TRANSACTIONS ON NUCLEAR SCIENCE48(3)pp. 567-569 IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
Bentley MA, Williams SJ, Joss DT, O'Leary CD, Bruce AM, Cameron JA, Carpenter MP, Fallon P, Frankland L, Gelletly W, Lister CJ, Martinez-Pinedo G, Poves A, Regan PH, Reiter P, Rubio B, Sanchez-Solano J, Seweryniak D, Svensson CE, Vincent SM, Warner DD (2002) Mirror symmetry and Coulomb effects in light N approximate to Z nuclei, CZECHOSLOVAK JOURNAL OF PHYSICS52pp. C597-C606 INST PHYSICS ACAD SCI CZECH REPUBLIC
Alharbi T, Mason PJR, Regan PH, Mrginean N, Podolyák Z, Algora A, Alazemi N, Bruce AM, Britton R, Bunce MR, Bucurescu D, Cooper N, Deleanu D, Filipescu D, Gelletly W, Ghit D, Glodariu T, Ilie G, Kisyov S, Lintott J, Lalkovski S, Liddick S, Mihai C, Mulholland K, Mrginean R, Negret A, Nakhostin M, Roberts OJ, Rice S, Smith JF, Stroe L, Sava T, Townsley C, Wilson E, Werner V, Zhekova M, Zamfir NV (2012) Electromagnetic transition rate measurements in the N=80 isotone, 138Ce, Journal of Physics: Conference Series381(1)
A study of intrinsic state halflife measurements in the N=80 nucleus 138Ce has been made using the 130Te( 12C,4n) 138Ce fusion evaporation reaction at beam energy of 56 MeV. The fast-timing gamma-ray coincidence method was used with a mixed LaBr 3(Ce)-HPGe array to establish the lifetimes of the yrast 6 + state at 2294 keV, the I À=5 - state at 2218 keV, the I À=11 + state at 3943 keV and the 14 + state at that at 5312 keV, all of which are in the sub nanosecond regime. Reduced transition probabilities have been calculated for the electromagnetic decays from these states. © Published under licence by IOP Publishing Ltd.
Daugas JM, Grzywacz R, Lewitowicz M, Achouri L, Angelique JC, Baiborodin D, Bennaceur K, Bentida R, Beraud R, Borcea C, Bingham C, Catford WN, Emsallem A, de France G, Grawe H, Jones KL, Lemmon RC, Jimenez MJL, Nowacki F, Santos FD, Pfutzner M, Regan PH, Rykaczewski K, Sauvestre JE, Sawicka M, Sletten G, Stanoiu M (2000) The 8(+) isomer in Zn-78 and the doubly magic character of Ni-78, PHYSICS LETTERS B476(3-4)pp. 213-218 ELSEVIER SCIENCE BV
Habib AS, Bradley DA, Regan PH, Shutt AL (2010) The use of MCNP and gamma spectrometry in supporting the evaluation of NORM in Libyan oil pipeline scale, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT619(1-3)pp. 245-251 ELSEVIER SCIENCE BV
Farrelly GF, Podolyak Z, Steer SJ, Pietri S, Xu FR, Werner-Malento E, Shizuma T, Regan PH, Rudolph D, Garnsworthy AB, Hoischen R, Gorska M, Gerl J, Wollersheim HJ, Kurtukian-Nieto T, Benzoni G, Becker F, Bednarczyk P, Caceres L, Doornenbal P, Geisserl H, Grebosz J, Kelic A, Kojouharov I, Kurz N, Montes F, Prokopowicz W, Saito T, Schaffner H, Tashenov S, Heinz A, Pfuezner M, Jungclaus A, Balabanski DL, Brandau C, Bruce AM, Catford WN, Cullen IJ, Dombradi Z, Estevez E, Gelletly W, Ilie G, Jolie J, Jones GA, Kmiecik M, Kondev FG, Kruecken R, Lalkovski S, Liu HL, Liu Z, Maj A, Myalski S, Schwerrel S, Walker PM, Wieland O (2009) REVISION OF THE K-ISOMER IN W-190(116),ACTA PHYSICA POLONICA B40(3)pp. 885-888 WYDAWNICTWO UNIWERSYTETU JAGIELLONSKIEGO
Soderstrom P-A, Recchia F, Nyberg J, Gadea A, Lenzi SM, Poves A, Atac A, Aydin S, Bazzacco D, Bednarczyk P, Bellato M, Birkenbach B, Bortolato D, Boston AJ, Boston HC, Bruyneel B, Bucurescu D, Calore E, Cederwall B, Charles L, Chavas J, Colosimo S, Crespi FCL, Cullen DM, de Angelis G, Desesquelles P, Dosme N, Duchene G, Eberth J, Farnea E, Filmer F, Gorgen A, Gottardo A, Grebosz J, Gulmini M, Hess H, Hughes TA, Jaworski G, Jolie J, Joshi P, Judson DS, Jungclaus A, Karkour N, Karolak M, Kempley RS, Khaplanov A, Korten W, Ljungvall J, Lunardi S, Maj A, Maron G, Meczynski W, Menegazzo R, Mengoni D, Michelagnoli C, Molini P, Napoli DR, Nolan PJ, Norman M, Obertelli A, Podolyak Z, Pullia A, Quintana B, Redon N, Regan PH, Reiter P, Robinson AP, Sahin E, Simpson J, Salsac MD, Smith JF, Stezowski O, Theisen C, Tonev D, Unsworth C, Ur CA, Valiente-Dobon JJ, Wiens A (2012) High-spin structure in K-40, PHYSICAL REVIEW C86(5)ARTN 054320 AMER PHYSICAL SOC
Parry CM, Boston AJ, Chandler C, Galindo-Uribarri A, Hibbert IM, Janzen VP, Joss DT, Mullins SM, Nolan PJ, Paul ES, Regan PH, Vincent SM, Wadsworth R, Ward D, Wyss R (1998) Yrast structures in the neutron-deficient 12759Pr68 and 13161Pm70 nuclei, Physical Review C - Nuclear Physics57(5)pp. 2215-2221
The odd-proton nuclei 127Pr and 131Pm have been investigated using the 96Ru(35Cl,2p2n) and 96Ru(40Ca,±p)/96Ru(39K,2p2n) reactions, respectively, at beam energies of 164, 180, and 186 MeV. States belonging to the yrast bands of 127Pr and 131Pm, which are interpreted as being based upon the h11/2 [541]3/2- proton configuration, have been observed from the 11/2- band head to spin 47/2-. The properties of these two new structures are observed to be different to those of similar configurations in the heavier odd mass isotopes. The systematics of the band crossings in the Àh11/2 bands of the odd mass Pr and Pm isotopes are discussed and compared with extended total Routhian surface calculations.
Lewitowicz M, Daugas JM, Grzywacz R, Achouri L, Angélique JC, Baiborodin D, Bentida R, Béraud R, Bingham C, Borcea C, Catford W, Emsallem A, De France G, Glogowski M, Grawe H, Guillemaud-Mueller D, Houry M, Hurskanen S, Jones KL, Lemmon RC, Mueller AC, Nowak A, De Oliveira-Santos F, PBochocki A, Pfützner M, Regan PH, Rykaczewski K, Saint-Laurent MG, Sauvestre JE, Sawicka M, Schaefer M, Sletten G, Sorlin O, Stanoiu M, Szerypo J, Trinder W, Viteritti S, Winfield J (1999) Study of ¼s-isomers in neutron-rich nuclei around Z=28 and N=40 shell closures, Nuclear Physics A654(1 SUPPL. 1)
Caceres LS, Gorska M, Jungclaus A, Regan PH, Garnsworthy AB, Pietri S, Podolyak Z, Rudolph D, Steer SJ, Grawe H, Balabanski DL, Becker F, Bednarczyk P, Benzoni G, Blank B, Brandau C, Bruce AM, Camera F, Catford WN, Cullen IJ, Dombradi Z, Doornenbalal P, Estevez E, Geissel H, Gelletly W, Gerl J, Grebosz J, Heinz A, Hoischen R, Ilie G, Jolie J, Jones GA, Kmiecik M, Kojouharov I, Kondev FG, Kurtukian-Nieto T, Kurz N, Lalkowski S, Liu L, Maj A, Myalsk S, Montes F, Pfuetzner M, Prokopowicz W, Saito T, Schatfner H, Schwertel S, Shizuma T, Simons AJ, Tashenov S, Walker PM, Werner-Malento E, Wielandh O, Wollersheim HJ (2007) Identification of excited states in the N = Z nucleus Nb-82, ACTA PHYSICA POLONICA B38(4)pp. 1271-1275 ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS
SIMMONS PM, RAE WDM, CHAPPELL SPG, FOX SP, JONES CD, WATSON DL, FREER M, FULTON BR, CLARKE NM, CURTIS N, LEDDY MJ, POPLE JS, HALL SJ, WARD RP, TUNGATE G, CATFORD WN, GYAPONG GJ, SINGER SM, REGAN PH (1995) SEARCH FOR A 7-ALPHA CHAIN STATE, PHYSICAL REVIEW C51(6)pp. 3500-3503 AMERICAN PHYSICAL SOC
Steer SJ, PodolyÁk ZS, Pietri S, GÓrska M, Farrelly GF, Regan PH, Rudolph D, Garnsworthy AB, Hoischen R, Gerl J, Wollersheim HJ, Grawe H, Maier KH, Becker F, Bednarczyk P, CÁceres L, Doornenbal P, Geissel H, Grbosz J, Kelic A, Kojouharov I, Kurz N, Montes F, Prokopowicz W, Saito T, Schaffner H, Tashenov S, Heinz A, Kurtukian-Nieto T, Benzoni G, PfÜtzner M, Jungclaus A, Balabanski DL, Brandau C, Brown A, Bruce AM, Catford WN, Cullen IJ, DombrÁdi Z, Estevez ME, Gelletly W, Ilie G, Jolie J, Jones GA, Kmiecik M, Kondev FG, KrÜcken R, Lalkovski S, Liu Z, Maj A, Myalski S, Schwertel S, Shizuma T, Walker PM, Werner-Malento E, Wieland O (2009) Isomeric decay studies in neutron-rich N H 126 nuclei,International Journal of Modern Physics E18(4)pp. 1002-1007 Heavy neutron-rich nuclei were populated via relativistic energy fragmentation of a
E/A=1 GeV 208Pb beam. The nuclei of interest were selected and identified by a fragment
separator and then implanted in a passive plastic stopper. Delayed rays following
internal isomeric decays were detected by the RISING array. Experimental information
was obtained on a number of nuclei with Z=73-80 (Ta-Hg), providing new information
both on the prolate-oblate transitional region as well as on the N=126 closed shell nuclei.
Myalski S, Maj A, Podolyák Z, Kmiecik M, Bednarczyk P, Grebosz J, Regan PH, Garnsworthy AB, Pietri S, Rudolph D, Steer SJ, Becker F, Gerl J, Górska M, Grawe H, Kojouharov I, Schaffner H, Wollersheim HJ, Prokopowicz W, Benzoni G, Blank B, Brandau C, Bruce AM, Cáceres L, Camera F, Catford WN, Cullen IJ, Dombradi Z, Doornenbal P, Estevez E, Geissel H, Gelletly W, Heinz A, Hoischen R, Ilie G, Jones GA, Jungclaus A, Kelic A, Kondev FG, Kurtukian-Nieto T, Kurz N, Lalkovski S, Liu Z, Montes F, Pfützner M, Saito T, Shizuma T, Simons AJ, Schwertel S, Tachenov S, Walker PM, Werner-Malento E, Wieland O (2012) Study of isomer production rates for A = 142-152 and Z = 62-67 in fragmentation of a relativistic 208Pb beam, Acta Physica Polonica B43(2)pp. 253-259
We have investigated nuclear fragmentation reactions of a relativistic 208Pb beam.Ten isomeric states for nuclei with A = 142-152 and Z = 62-67 were observed. Measured isomeric ratios were compared, together with values from other experiments, with prediction of theoretical models. The discrepancies between the experimental and theoretical values were discussed in terms of transitions by-passing the isomer that are not included in the models.
Lazarus IH, Appelbe DE, Butler PA, Coleman-Smith PJ, Cresswell JR, Freeman SJ, Herzberg RD, Hibbert I, Joss DT, Letts SC, Page RD, Pucknell VFE, Regan PH, Sampson J, Simpson J, Thornhill J, Wadsworth R (2000) The GREAT triggerless total data readout method,IEEE Nuclear Science Symposium and Medical Imaging Conference2 Recoil Decay Tagging (RDT) is a very powerful method for the spectroscopy of exotic nuclei. RDT is a delayed coincidence technique between detectors usually at the target position and at the focal plane of a spectrometer. Such measurements are often limited by dead time. This paper describes a novel triggerless data acquisition method which is being developed for the Gamma Recoil Electron Alpha Tagging (GREAT) spectrometer that overcomes this limitation by virtually eliminating dead time. Our solution is a Total Data Readout (TDR) method where all channels run independently and are associated in software to reconstruct events. The TDR method allows all the data from both target position and focal plane to be collected with practically no dead time losses. Each data word is associated with a timestamp generated from a global 100MHz clock. Events are then reconstructed in real time in the event builder using temporal and spatial associations defined by the physics of the experiment.
Bunce M, Regan PH, Werner V, Anagnostatou V, Beausang CW, Bowry M, Casperson RJ, Chen D, Cooper N, Goddard P, Hughes RO, Ilie G, Mason PJR, Pauerstein B, Reed MW, Ross TJ (2012) A shell model study of the high spin states of 88Y, Journal of Physics: Conference Series381(1)
Experiments were carried out at the Wright Nuclear Structure Laboratory at Yale University using the 21MV ESTU Tandem Van de Graaff accelerator with the purpose of studying 88Y. A beam of 18O impinged at laboratory energies of 60, 65 and 70 MeV on a 600 ¼g/cm 274Ge target with a thick (10mg/cm 2) 197Au backing. This experiment was performed with the specific aim of accessing medium spin states of the nucleus of interest. A second experiment was undertaken to populate the nucleus of interest in higher spin states by impinging the same 18O beam on a thin 62 ¼g/cm 276Ge target with a 20 ¼g/cm 2 carbon backing at a laboratory beam energy of 90 MeV. Gamma rays emitted following the decay of excited states in 88Y and other nuclei populated in the reactions were measured using the YRAST ball detector array, consisting of 10 Compton suppressed HPGe clover detectors. In conjunction with the experimental study presented here, nuclear shell model calculations using a truncated valence space have also been performed in an attempt to describe the single-particle make-up of the states observed. Preliminary results from these experiments and theoretical calculations are presented. © Published under licence by IOP Publishing Ltd.
Mineva AN, Hellstrom M, Bernas M, Gerl J, Grawe H, Pfutzner M, Regan PH, Rejmund M, Rudolph D, Becker F, Bingham CR, Enqvist T, Fogelberg B, Gausemel H, Geissel H, Genevey J, Gorska M, Grzywacz R, Hauschild K, Janas Z, Kojouharov I, Kopatch Y, Korgul A, Korten W, Kurcewicz J, Lewitowicz M, Lucas R, Mach H, Mandal S, Mayet P, Mazzocchi C, Pinston JA, Podolyak Z, Schaffner H, Schlegel C, Schmidt K, Summerer K, Wollersheim HJ (2001) A new mu s isomer in Sb-136 produced in the projectile fission of U-238, EUROPEAN PHYSICAL JOURNAL A11(1)pp. 9-13 SPRINGER-VERLAG
Britton R, Regan PH, Burnett J, Davies A (2012) Determining the efficiency of a broad-energy HPGe detector using Monte Carlo simulations, Journal of Radioanalytical and Nuclear Chemistrypp. 1-7
Broad-energy HPGe detectors have a useful range of 3 keV to 3 MeV, making them ideal for the assay of environmental samples. Such measurements however, are hindered by variations in the sample matrix, summing effects, and the Compton continuum. Detectors may be characterised by proprietary software in such a situation, however Monte-Carlo modelling is a useful, inexpensive alternative that also provides greater flexibility when determining the detector response and efficiency during a measurement. In the current work, a full GEANT4 model of a broad-energy HPGe detector is presented, and simulations of various samples are compared to experimental data. These are found to be accurate within 3 % at a confidence level of 95 % for energies from 30 to 3,000 keV, with greater variations below 100 keV due to an increased sensitivity to geometrical inaccuracies. © 2012 Akadémiai Kiadó, Budapest, Hungary.
Benzoni G, Azaiez F, Stefan GI, Franchoo S, Battacharyya S, Borcea R, Bracco A, Corradi L, Curien D, De France G, Dombradi Z, Fioretto E, Grevy S, Ibrahim F, Leoni S, Montanari D, Mukherjee G, Pollarolo G, Redon N, Regan PH, Schmitt C, Sletten G, Sohlers D, Stanoiu M, Szilner S, Verney D (2010) Study of collisions of the radioactive Ne-24 beam at 7.9 MeV/u on Pb-208, EUROPEAN PHYSICAL JOURNAL A45(3)pp. 287-292 SPRINGER
Valencia E, Tain JL, Algora A, Agramunt J, Estevez E, Jordan MD, Rubio B, Rice S, Regan Patrick, Gelletly William, Podolyak Zsolt, Bowry M, Mason P, Farrelly GF, Zakari-Issoufou A, Fallot M, Porta A, Bui VM (2017) Total absorption ³ -ray spectroscopy of the ²-delayed neutron emitters 87Br, 88Br, and 94Rb,Physical Review C: Nuclear Physics024320 American Physical Society
We investigate the decay of 87,88Br and 94Rb using total absorption ³ -ray spectroscopy. These important fission products are ²-delayed neutron emitters. Our data show considerable ²³ intensity, so far unobserved in high-resolution ³ -ray spectroscopy, from states at high excitation energy. We also find significant differences with the ² intensity that can be deduced from existing measurements of the ² spectrum. We evaluate the impact of the present data on reactor decay heat using summation calculations. Although the effect is relatively small it helps to reduce the discrepancy between calculations and integral measurements of the photon component for 235U fission at cooling times in the range 1?100 s. We also use summation calculations to evaluate the impact of present data on reactor antineutrino spectra. We find a significant effect at antineutrino energies in the range of 5 to 9 MeV. In addition, we observe an unexpected strong probability for ³ emission from neutron unbound states populated in the daughter nucleus. The ³ branching is compared to Hauser-Feshbach calculations, which allow one to explain the large value for bromine isotopes as due to nuclear structure. However the branching for 94Rb, although much smaller, hints of the need to increase the radiative width ³ by one order of magnitude. This increase in ³ would lead to a similar increase in the calculated (n,³ ) cross section for this very neutron-rich nucleus with a potential impact on r process abundance calculations.
Britton R, Burnett JL, Davies AV, Regan PH (2014) Characterisation of cascade summing effects in gamma spectroscopy using Monte Carlo simulations, Journal of Radioanalytical and Nuclear Chemistry299(1)pp. 447-452
A GEANT4 based Monte Carlo simulation has been successfully utilised to calculate peak efficiency characterisations and cascade summing (true coincidence summing) corrections in two source geometries commonly used for environmental monitoring. The cascade summing corrections are compared with values generated using an existing (validated) system, and found to be in excellent agreement for all radionuclides simulated. The calculated correction factors and peak efficiencies were also tested by analysing well defined sources used in the operation of the International Monitoring System, which undertakes radionuclide monitoring for verification of the Comprehensive Nuclear-Test-Ban Treaty. All abundances of the radionuclides measured matched the values that were previously determined using proprietary software. Using GEANT4 in this way, cascade summing corrections can now be extended to complex detector models and source matrices, such as Compton Suppression systems. © 2013 Akadémiai Kiadó, Budapest, Hungary.
Singh BSN, Liu Z, Wadsworth R, Grawe H, Brock TS, Boutachkov P, Braun N, Blazhev A, Gorska M, Pietri S, Rudolph D, Domingo-Pardo C, Steer SJ, Atac A, Bettermann L, Caceres L, Eppinger K, Engert T, Faestermann T, Farinon F, Finke F, Geibel K, Gerl J, Gernhaeuser R, Goel N, Gottardo A, Grebosz J, Hinke C, Hoischen R, Ilie G, Iwasaki H, Jolie J, Kaskas A, Kojouharov I, Kruecken R, Kurz N, Merchan E, Nociforo C, Nyberg J, Pfuetzner M, Prochazka A, Podolyak Z, Regan PH, Reiter P, Rinta-Antila S, Scholl C, Schaffner H, Soderstrom P-A, Warr N, Weick H, Wollersheim H-J, Woods PJ, Nowacki F, Sieja K (2011) 16(+) Spin-Gap Isomer in Cd-96, PHYSICAL REVIEW LETTERS107(17)ARTN 172502
Santawamaitre T, Malain D, Al-Sulaiti HA, Bradley DA, Matthews MC, Regan PH (2014) Determination of (238)U, (232)Th and (40)K activity concentrations in riverbank soil along the Chao Phraya river basin in Thailand., J Environ Radioact138pp. 80-86
The activity concentrations of (238)U, (232)Th and (40)K in riverbank soil along the Chao Phraya river basin was determined through gamma-ray spectrometry measurements made using a hyper-pure germanium detector in a low background configuration. The ranges of activity concentrations of (238)U, (232)Th and (40)K were found to be 13.9 76.8, 12.9 142.9 and 178.4 810.7 Bq kg(-1), respectively. The anthropogenic radionuclide, (137)Cs, was not observed in statistically significant amounts above the background level in the current study. The absorbed gamma dose rate in air at 1 m above the ground surface, the outdoor annual effective dose equivalent, the values of the radium equivalent activity and the external hazard index associated with all the soil samples in the present work were evaluated. The results indicate that the radiation hazard from primordial radionuclides in all soil samples from the area studied in this current work is not significant.
A novel dibenzo-18-crown-6 ether (DB-18CE-6)- functionalised silica (SiO2) disk was found to be a capable
source preparation technique for the rapid analysis of 226Ra by alpha-spectrometry. DB-18CE-6 was chemically
immobilised onto the surface of SiO2 disks. It is anticipated that the high levels of selectivity of DB-18CE-6 for
radium will allow for an efficient chemical separation of 226Ra from other elements present in sample matrices.
226Ra was adsorbed as a monolayer onto the surface of the silica disks, attaching to the functionalised centres of
the DB-18CE-6 structure, forming a high resolution counting source for alpha-spectrometry. The chemical
recovery of radium from synthetic samples was 2.3% at pH 2, with higher recoveries expected over the pH range
of 4?10.
Régis J.-M., Jolie J., Saed-Samii N., Warr N., Pfeiffer M., Blanc A., Jentschel M., Köster U., Mutti P., Soldner T., Simpson G. S., Drouet F., Vancraeyenest A., de France G., Clément E., Stezowski O., Ur C. A., Urban W., Regan Patrick, Podolyak Zsolt, Larijani Cyrus Kouroush, Townsley C., Carroll R., Wilson E., Fraile L. M., Mach H., Paziy V., Olaizola B., Vedia V., Bruce A. M., Roberts O. J., Smith J. F., Scheck M., Kröll T., Hartig A.-L., Ignatov A., Ilieva S., Lalkovski S., Korten W., M?rginean N., Otsuka T., Shimizu N., Togashi T., Tsunoda Y. (2017) Abrupt shape transition at neutron number N=60 : B(E2) values in Sr94,96,98 from fast ³?³ timing,Physical Review C95(5)054319pp. 054319-1 American Physical Society
Lifetimes of low-lying yrast states in neutron-rich 94,96,98Sr have been measured by Germanium-gated ³?³ fast timing with LaBr3(Ce) detectors using the EXILL&FATIMA spectrometer at the Institut Laue-Langevin. Sr fission products were generated using cold-neutron-induced fission of 235U and stopped almost instantaneously within the thick target. The experimental B(E2) values are compared with results of Monte Carlo shell-model calculations made without truncation on the occupation numbers of the orbits spanned by eight proton and eight neutron orbits and show good agreement. Similarly to the Zr isotopes, the abrupt shape transition in the Sr isotopes near neutron number N=60 is identified as being caused by many-proton excitations to its g9/2 orbit.
Söderström P, Walker PM, Wu J, Liu H, Regan PH, Watanabe H, Doornenbal P, Korkulu Z, Lee P, Liu J, Lorusso G, Nishimura S, Phong V, Sumikama T, Xu F, Yagi A, Zhang G, Ahn D, Alharbi T, Baba H, Browne F, Bruce A, Carroll R, Chae K, Dombradi Z, Estrade A, Fukuda N, Griffin C, Ideguchi E, Inabe N, Isobe T, Kanaoka H, Kanaya S, Kojouharov I, Kondev F, Kubo T, Kubono S, Kurz N, Kuti I, Lalkovski S, Lane G, Lee E, Lee C, G. Lotay G, Moon C, Nishizuka I, Nita C, Odahara A, Patel Z, Podolyak Z, Roberts O, Sakurai H, Schaffner H, Shand C, Suzuki H, Takeda H, Terashima S, Vajta Z, Valiente-Dòbon J, Xui Z (2016) Collective And Single-particle Structures In The Neutron-rich Doubly Mid-shell Nucleus 170Dy,Proceedings of Science: The 26th International Nuclear Physics Conference One of the most successful descriptions of the structure of atomic nuclei is the spherical shell
model. It, however, becomes impractical when moving away from closed-shell nuclei. Instead, it
is the interplay between the macroscopic shape degrees of freedom and the microscopic nature of
the underlying single-particle structure in a deformed basis that determines the nuclear structure.
Being the heaviest nucleus precisely in the middle of, known, closed proton and neutron shells,
170Dy has become a central calibration point for tests of collective models of nuclear physics.
However, besides one candidate transition from a previous experiment in Legnaro, Italy, no experimental
information is available for this nucleus. Using the EURICA setup at RIKEN, which
couples the worlds highest intensity in-flight fission facility with a high-efficiency HPGe array,
an experiment in November 2014 produced 170Dy nuclei by in-flight fission of a 238U beam. The
results from this experiment provide a wealth of information on this elusive nucleus, including the
evolution of quadrupole collectivity, rigidity and higher order deformations, as well as the long
sought for isomeric K = 6+ state, predicted to be exceptionally pure at mid-shell. These results
provide us with a rich level scheme for discussing both single-particle and collective structures at
mid-shell.
Wu J, Nishimura S, Lorusso G, Moller P, Ideguchi E, Regan PH, Simpson G, Soderstrom P, Walker PM, Watanabe H, Xu Z, Baba H, Browne F, Daido R, Doornenbal P, Fang Y, Gey G, Isobe T, Lee P, Liu J, Li Z, Korkulu Z, Patel Z, Phong V, Rice S, Sakurai H, Sinclair L, Sumikama T, Tanaka M, Yagi A, Ye Y, Yokoyama R, Zhang G, Alharbi T, Aoi N, Bello Garrote F, Benzoni G, Bruce A, Carroll R, Chae K, Dombradi Z, Estrade A, Gottardo A, Griffin C, Kanaoka H, Kojouharov I, Kondev F, Kubono S, Kurz N, Kuti I, Lalkovski S, Lane G, Lee E, Lokotko T, Lotay GJ, Moon C, Nishibata H, Nishizuka I, Nita C, Odahara A, Podolyak Z, Roberts O, Schaffner H, Shand CM, Taprogge J, Terashima S, Vajta Z, Yoshida S (2017) 94 -Decay Half-lives of Neutron-Rich 55Cs to 67Ho: Experimental Feedback and Evaluation of the r-Process Rare-Earth Peak Formation,Physical Review Letters118(7)072701 American Physical Society
The -decay half-lives of 94 neutron-rich nuclei 144?151Cs, 146?154Ba, 148?156La, 150?158Ce, 153?160Pr, 156?162Nd, 159?163Pm, 160?166Sm, 161?168Eu, 165?170Gd, 166?172Tb, 169?173Dy, 172?175Ho and two isomeric states 174mEr, 172mDy were measured at Radioactive Isotope Beam Factory (RIBF), providing a new experimental basis to test theoretical models. Striking, large drops of -decay half-lives are observed at neutron-number N = 97 for 58Ce, 59Pr, 60Nd, 62Sm, and N = 105 for 63Eu, 64Gd, 65Tb, 66Dy. Features in the data mirror the interplay between pairing effects and microscopic structure. r-Process network calculations performed for a range of mass models and astrophysical conditions show that the 57 half-lives measured for the first time play an important role in shaping the abundance pattern of rare-earth elements in the solar system.
Twenty-three oil scale samples obtained from the Libyan oil and gas industry production facilities onshore have been measured using high-resolution gamma-ray spectrometry with a shielded HPGe detector, the work being carried out within the Environmental Radioactivity Laboratory at the University of Surrey. The main objectives of this work were to determine the extent to which the predominant radionuclides associated with the uranium and thorium natural decay chains were in secular equilibrium with their decay progeny, also to compare differences between the total activity concentrations (TAC) in secular equilibrium and disequilibrium and to evaluate the measured activities for the predominant gamma-ray emitting decay radionuclides within the 232Th and 238U chains. The oil scale NORM samples did not exhibit radioactive equilibrium between the decay progeny and longer-lived parent radionuclides of the 238U and 232Th series.
Gurgi LA, Regan PH, Daniel T, Podolyak Z, Bruce A, Mason P, MÎrginean N, MÎrginean R, Werner V, Alharbi T, Alkhomashi N, Bajoga A, Britton R, CÎta-Danil I, Carroll R, Deleanu D, Bucurescu D, Florea N, Gheorghe I, Ghita D, Lice R, Mihai C, Mulholland K, Negret A, Olacel A, Roberts O, Sava T, Söderström P, Stroe L, Suvaila R, Toma S, Wilson E, Wood R (2016) Nanosecond lifetime measurements of IÀ¼9/2- intrinsic excited states and low-lying B(E1)strengths in 183Re using combined HPGe-LaBr3 coincidence spectroscopy,Radiation Physics and Chemistry137pp. 7-11 Elsevier
This paper presents precision measurements of electromagnetic decay probabilities associated with electric dipole transitions in the prolate-deformed nucleus 183Re. The nucleus of interest was formed using the fusion evaporation reaction 180Hf(7Li,4n)183Re at a beam energy of 30 MeV at the tandem accelerator at the HH-IFIN Institute, Bucharest Romania. Coincident decay gamma rays from near-yrast cascades were detected using the combined HPGe-LaBr3 detector array ROSPHERE. The time differences between cascade gamma rays were measured using the LaBr3 detectors to determine the half-lives of the two lowest lying spin-parity 9/2- states at excitation energies of 496 and 617 keV to be 5.65(5) and 2.08(3) ns respectively. The deduced E1 transition rates from these two states are discussed in terms of the K-hindrance between the low-lying structures in this prolate-deformed nucleus.
Rice S, Algora A, Tain J, Valencia E, Agramunt J, Rubio B, Gelletly W, Regan P, Zakari-Issoufou A, Fallot M, Porta A, Rissanen J, Eronen T, Aysto J, Batist L, Bowry M, Bui V, Caballero-Folch R, Cano-Ott D, Elomaa V, Estevez E, Farrelly G, Garcia A, Gomez-Hornillos B, Gorlychev V, Hakala J, Jordan M, Jokinen A, Kolhinen V, Kondev F, Martinez T, Mendoza E, Moore I, Penttila H, Podolyak Z, Reponen M, Sonnenschein V, Sonzogni A, Sarriguren P (2017) Total Absorption Spectroscopy Study of the Beta Decay of 86Br and 91 1 Rb,Physical Review C96014320 American Physical Society
The beta decays of 86Br and 91Rb have been studied using the total absorption spectroscopy
technique. The radioactive nuclei were produced at the IGISOL facility in Jyvaskyla and further
purified using the JYFLTRAP. 86Br and 91Rb are considered high priority contributors to the decay
heat in reactors. In addition 91Rb was used as a normalization point in direct measurements of
mean gamma energies released in the beta decay of fission products by Rudstam et al. assuming
that this decay was well known from high-resolution measurements. Our results shows that both
decays were suffering from the Pandemonium effect and that the results of Rudstam et al. should
be renormalized.
Mason P, Podolyak Z, Marginean N, Regan PH, Stevenson PD, Werner V, Alexander T, Algora A, Alharbi T, Bowry M, Britton R, Bruce A, Bucurescu D, Bunce M, Cata-Danil G, Cata-Danil I, Cooper N, Deleanu D, Delion D, Filipescu D, Gelletly W, Ghita D, Gheorghe I, Glodariu T, Ilie G, Ivanova D, Kisyov S, Lalkovski S, Lica R, Liddick S, Marginean R, Mihai C, Mulholland K, Nita C, Negret A, Pascu S, Rice S, Roberts O, Sava T, Smith J, Soederstroem P, Stroe L, Suliman G, Suvaila R, Toma S, Townsley C, Wilson E, Wood RT, Zhekova M, Zhou C (2013) Half-life of the yrast 2(+) state in W-188: Evolution of deformation and collectivity in neutron-rich tungsten isotopes,PHYSICAL REVIEW C88(4)044301 AMER PHYSICAL SOC
The half-life of the yrast I À = 2+ state in the neutron-rich nucleus 188W has been measured using fast-timing
techniques with the HPGe and LaBr3:Ce array at the National Institute of Physics and Nuclear Engineering,
Bucharest. The resulting value of t1/2 = 0.87(12) ns is equivalent to a reduced transition probability of
B(E2; 2+
1 0+
1 ) = 85(12) W.u. for this transition. The B(E2; 2+
1 0+
1 ) is compared to neighboring tungsten
isotopes and nuclei in the Hf, Os, and Pt isotopic chains. Woods-Saxon potential energy surface (PES) calculations
have been performed for nuclei in the tungsten isotopic chain and predict prolate deformed minima with rapidly
increasing ³ softness for 184?192W and an oblate minimum for 194W.
Wilson J, Lebois M, Qi L, Amador-Celdran P, Bleuel D, Briz J, Carroll R, Catford WN, De Witte H, Doherty D, Eloirdi R, Georgiev G, Gottardo A, Goasduff A, Hadynska-Klek K, Hauschild K, Hess M, Ingeberg V, Konstantinopoulos T, Ljungvall J, Lopez-Martens A, Lorusso G, Lozeva R, Lutter R, Marini P, Matea I, Materna T, Mathieu L, Oberstedt A, Oberstedt S, Panebianco S, Podolyak Z, Porta D, Regan PH, Reiter P, Rezynkina K, Rose S, Sahin E, Seidlitz M, Shearman R, Siebeck B, Siem S, Smith A, Tveten G, Verney D, Warr N, Zeiser F, Zielinska M (2017) PRODUCTION AND STUDY OF NEUTRON-RICH NUCLEI USING THE LICORNE DIRECTIONAL NEUTRON SOURCE,Acta Physica Polonica B48(3)pp. 395-401 Pan?stwowe Wydawn. Naukowe
We have recently successfully demonstrated a new technique for production and study of many of the most exotic neutron-rich nuclei at moderate spins. LICORNE, a newly developed directional inverse-kinematic fast neutron source at the IPN Orsay, was coupled to the MINIBALL high resolution -ray spectrometer to study nuclei the furthest from stability using the 238U(n; f) reaction. This reaction and 232Th(n; f) are the most neutron-rich fission production mechanisms achievable and can be used to simultaneously populate hundreds of neutron-rich nuclei up to spins of 16 ~. High selectivity in the experiment was achieved via triple -ray coincidences and the use of a 400 ns period pulsed neutron beam, a technique which is unavailable to other population mechanisms such as 235U(nth; f) and 252Cf(SF). The pulsing allows time correlations to be exploited to separate delayed rays from isomeric states in the hundreds of nuclei produced, which are then used to cleanly select a particular nucleus and its exotic binary partners. In the recent experiment, several physics cases are simultaneously addressed such as shape coexistence, the evolution of shell closures far from stability, and the spectroscopy of nuclei in the r-process path near N = 82. Preliminary physics results on anomalies in the 238U(n; f) fission yields and the structure of the 138Te and 100Sr nuclei will soon be published. A future project, -ball, to couple LICORNE with a hybrid escape-suppressed spectrometer to refine further the technique and achieve a large increase in the observational limit is discussed.
Courtin S, Fruet G, Jenkins D, Heine M, Montanari D, Morris L, Lotay GJ, Regan PH, Kirsebom O, Della Negra S, Hammache F, De Sereville N, Bastin B, de Oliveira F, Randisi G, Stodel C, Beck C, Haas F (2017) Fusion Cross Sections of Astrophysics Interest Within the STELLA Project.,Proceedings of the 14th International Symposium on Nuclei in the Cosmos (NIC2016) 2017021001 Physical Society of Japan
Low energy fusion between light heavy-ions is a key feature of the evolution of massive stars. In systems of astrophysical interest, the process may be strongly affected by molecular configurations of the compound nucleus, leading to resonant S factors. In particular, the 12C+12C fusion reaction has been the object of numerous experimental investigations. The STELLA project has been developed to extend these investigations to lower energies towards the Gamow window.
Spagnoletti P, Simpson G, Carroll R, Regis J, Blanc A, Jentschel M, Koster U, Mutti P, Soldner T, de France G, Ur C, Urban W, Bruce A, Drouet F, Fraile L, Gaffney L, GhitØa D, Ilieva S, Jolie J, Korten W, Kroll T, Larijarni C, Lalkovski S, Lica R, Mach H, Marginean N, Paziy V, Podolyak Z, Regan PH, Scheck M, Saed-Samii N, Thiamova G, Townsley C, Vancraeyenest A, Vedia V, Gargano A, Van Isacker P (2017) Half-life of the 15/2+ state of 135I: A test of E2 seniority relations,Physical Review C: Nuclear Physics95021302 American Physical Society
The half-life of the 15/2+ 1 state of the 3-valence-proton nucleus 135I has been measured to be 1.74(8) ns using the EXILL-FATIMA mixed array of Ge and LaBr3 detectors. The nuclei were produced following the cold neutron-induced fission of a 235U target at the PF1B beam line of the Institut Laue-Langevin. The extracted B(E2; 15/2+ 11/2+) value enabled a test of seniority relations for the first time between E2 transition rates. Large-scale shell-model calculations were performed for 134Te and 135I, and reinterpreted in a single-orbit approach. The results show that the two-body component of the E2 operator can be large whereas energy shifts due to the three-body component of the effective interaction are small.
The aim of the current work is to develop and validate a radiochemical separation scheme capable of separating both 236gNp and 236Pu from a uranium target of natural isotopic composition (~1 g uranium) and ~200 MBq of fission decay products. A target containing 1.2 g of UO2 was irradiated with a beam of 25 MeV protons with a typical beam current of 30 ¼A for 19 h in December 2013 at the University of Birmingham Cyclotron facility. Using literature values for the production cross-section for fusion of protons with uranium targets, we estimate that an upper limit of approximately 250 Bq of activity from the 236Np ground state was produced in this experiment. Using a radiochemical separation scheme, Np and Pu fractions were separated from the produced fission decay products, with analyses of the target-based final reaction products made using Inductively Couple Plasma Mass Spectrometry (ICP-MS) and high-resolution ± particle and ³-ray spectrometry.
The specific activity concentration of eight sand samples from three locations in the State of Espirito Santo, South Eastern Brazil have been determined for members of the 238U and 232Th decay series, as well as the primordial radionuclide 40K. The calculated activity concentration values and associated radiation hazard indices were evaluated. The thorium decay chain activities are significantly higher than that of comparable studies from other areas of the world, leading to calculated absorbed dose rate in air and radium equivalent activities which are higher than world averages. This is attributed to the geology of the monazite material which is ubiquitous in this region of Brazil. Trace elemental analysis was also carried out on these samples using Inductively Coupled Plasma Mass Spectrometry (ICP-MS).
Rice S, Algora A, Tain J, Valencia E, Agramunt J, Rubio B, Gelletly W, Regan PH, Zakari-Issoufou A, Fallot M, Porta A, Rissanen J, Eronen T, Äystö J, Batist L, Bowry M, Bui V, Caballero-Folch R, Cano-Ott D, Elomaa V, Estevez E, Farrelly G, Garcia A, Gomez-Hornillos B, Gorlychev V, Hakala J, Jordan M, Jokinen A, Kolhinen V, Kondev F, Martínez T, Mason P, Mendoza E, Moore I, Penttilä H, Podolyak Z, Reponen M, Sonnenschein V, Sonzogni A, Sarriguren P (2017) Total absorption spectroscopy study of the ² decay of 86Br and 91Rb,Physical Review C96(1)014320 American Physical Society
The beta decays of 86Br and 91Rb have been studied using the total absorption spectroscopy technique. The
radioactive nuclei were produced at the Ion Guide Isotope Separator On-Line facility in Jyväskylä and further
purified using the JYFLTRAP. 86Br and 91Rb are considered to be major contributors to the decay heat in reactors.
In addition, 91Rb was used as a normalization point in direct measurements of mean gamma energies released in
the beta decay of fission products by Rudstam et al. assuming that this decay was well known from high-resolution
measurements. Our results show that both decays were suffering from the Pandemonium effect and that the results
of Rudstam et al. should be renormalized. The relative impact of the studied decays in the prediction of the decay
heat and antineutrino spectrum from reactors has been evaluated
Patel Z, Walker P, Podolyak Z, Regan P, Berry T, Söderström P, Watanabe H, Ideguchi E, Simpson G, Nishimura S, Wu Q, Xu F, Browne F, Doornenbal P, Lorusso G, Rice S, Sinclair L, Sumikama T, Wu J, Xu Z, Aoi N, Baba H, Bello Garrote F, Benzoni G, Daido R, Dombrádi Z, Fang Y, Fukuda N, Gey G, Go S, Gottardo A, Inabe N, Isobe T, Kameda D, Kobayashi K, Kobayashi M, Komatsubara T, Kojouharov I, Kubo T, Kurz N, Kuti I, Li Z, Matsushita M, Michimasa S, Moon C, Nishibata H, Nishizuka I, Odahara A, Sahin E, Sakurai H, Schaffner H, Suzuki H, Takeda H, Tanaka M, Taprogge J, Vajta Z, Yagi A, Yokoyama R (2017) Isomer-delayed
-ray spectroscopy of A = 159 - 164 midshell nuclei and the variation of
K-forbidden E1 transition hindrance factors,Physical Review C96(3)034305 American Physical Society
Excited states have been studied in \iso{159}{Sm}, \iso{161}{Sm}, \iso{162}{Sm} (Z~=~62), \iso{163}{Eu} (Z~=~63), and \iso{164}{Gd} (Z~=~64), populated by isomeric decay following 238U projectile fission at RIBF, RIKEN. The isomer half-lives range from 50 ns to 2.6 \mus. In comparison with other published data, revised interpretations are proposed for \iso{159}{Sm} and \iso{163}{Eu}. The first data for excited states in \iso{161}{Sm} are presented, where a 2.6 \mus isomer is assigned a three-quasiparticle, K^\pi = 17/2^- structure. The interpretation is supported by multi-quasiparticle Nilsson-BCS calculations, including the blocking of pairing correlations. A consistent set of reduced E1 hindrance factors is obtained. Limited evidence is also reported for isomeric decay in 163Sm, 164Eu and 165Eu.
Gurgi Laila, Regan Patrick, Söderström P-A, Watanabe H, Walker Philip, Podolyak Zsolt, Nishimura S, Berry Thomas, Doornenbal P, Lorusso G, Isobe T, Baba H, Xu ZY, Sakurai H, Sumikama T, Catford Wilton, Bruce AM, Browne F, Lane GJ, Kondev FG, Odahara A, Wu J, Liu HL, Xu FR, Korkulu Z, Lee P, Liu JJ, Phong VH, Yag A, Zhang GX, Alharbi T, Carroll RJ, Chae KY, Dombradi Zs, Estrade A, Fukuda N, Griffin C, Ideguchi E, Inabe N, Kanaoka H, Kojouharov I, Kubo T, Kubono S, Kurz N, Kuti I, Lalkovski S, Lee EJ, Lee CS, Lotay Gavin, Moon C-B, Nishizuka I, Nita CR, Patel Z, Roberts OJ, Schaffner H, Shand Callum, Suzuki H, Takeda H, Terashima S, Vajta Zs, Yoshida S, Valiente-Dòbon JJ (2016) Isomer spectroscopy of neutron-rich 168Tb103,Radiation Physics and Chemistry140pp. 493-496 Elsevier
In-flight fission of a 345 MeV per nucleon 238U primary beam on a 2 mm thick 9Be target has been used to
produce and study the decays of a range of neutron-rich nuclei centred around the doubly mid-shell nucleus
170Dy at the RIBF Facility, RIKEN, Japan. The produced secondary fragments of interest were identified eventby-
event using the BigRIPS separator. The fragments were implanted into the WAS3ABI position sensitive
silicon active stopper which allowed pixelated correlations between implants and their subsequent ²-decay.
Discrete ³-ray transitions emitted following decays from either metastable states or excited states populated
following beta decay were identified using the 84 coaxial high-purity germanium (HPGe) detectors of the
EURICA spectrometer, which was complemented by 18 additional cerium-doped lanthanum bromide (LaBr3)
The safe and cost-effective decommissioning of legacy nuclear sites relies on accurate measurement of the
radioactivity content of the waste materials, so that the waste can be assigned to the most appropriate disposal
route. Such measurements are a new challenge for the science of radionuclide metrology which was established
largely to support routine measurements on operating nuclear sites and other applications such as nuclear
medicine. In this paper, we provide a brief summary of the international measurement system that is
established to enable nuclear site operators to demonstrate that measurements are accurate, independent and
fit for purpose, and highlight some of the projects that are underway to adapt the measurement system to meet
the changing demands from the industry.
Jentschel M, Blanc A, de France G, Köster U, Leoni S, Mutti P, Simpson G, Soldner T, Ur C, Urban W, Ahmed S, Astier A, Augey L, Back T, Ba'czyk P, Bajoga A, Balabanski D, Belgya T, Benzoni G, Bernards C, Biswas D, Bocchi G, Bottoni S, Britton R, Bruyneel B, Burnett J, Cakirli R, Carroll R, Catford W, Cederwall B, Celikovic I, Cieplicka-OryDczak N, Clement E, Cooper N, Crespi F, Csatlos M, Curien D, CzerwiDski M, Danu L, Davies A, Didierjean F, Drouet F, Duchêne G, Ducoin C, Eberhardt K, Erturk S, Fraile L, Gottardo A, Grente L, Grocutt L, Guerrero C, Guinet D, Hartig A, Henrich C, Ignatov A, Ilieva S, Ivanova D, John B, John R, Jolie J, Kisyov S, Krticka M, Konstantinopoulos T, Korgul A, Krasznahorkay A, Kröll T, Kurpeta J, Kuti I, Lalkovski S, Larijani C, Leguillon R, Lica R, Litaize O, Lozeva R, Magron C, Mancuso C, Martinez E, Massarczyk R, Mazzocchi C, Melon B, Mengoni D, Michelagnoli C, Million B, Mokry C, Mukhopadhyay S, Mulholland K, Nannini A, Napoli D, Olaizola B, Orlandi R, Patel Z, Paziy V, Petrache C, Pfeiffer M, Pietralla N, Podolyak Z, Ramdhane M, Redon N, Regan P, Regis J, Regnier D, Oliver R, Rudigier M, Runke J, Rza'ca-Urban T, Saed-Samii N, Salsac M, Scheck M, Schwengner R, Sengele L, Singh P, Smith J, Stezowski O, Szpak B, Thomas T, Thürauf M, Timar J, Tom A, Tomandl I, Tornyi T, Townsley C, Tuerler A, Valenta S, Vancraeyenest A, Vandone V, Vanhoy J, Vedia V, Warr N, Werner V, Wilmsen D, Wilson E, Zerrouki T, Zielinska M (2017) EXILL?a high-efficiency, high-resolution setup for ³-spectroscopy at an intense cold neutron beam facility,Journal of Instrumentation12(11)pp. P11003-P11003 IOP Publishing
In the EXILL campaign a highly efficient array of high purity germanium (HPGe) detectors was operated at the cold neutron beam facility PF1B of the Institut Laue-Langevin (ILL) to carry out nuclear structure studies, via measurements of ³-rays following neutron-induced capture and fission reactions. The setup consisted of a collimation system producing a pencil beam with a thermal capture equivalent flux of about 108 n s?1cm?2 at the target position and negligible neutron halo. The target was surrounded by an array of eight to ten anti-Compton shielded EXOGAM Clover detectors, four to six anti-Compton shielded large coaxial GASP detectors and two standard Clover detectors. For a part of the campaign the array was combined with 16 LaBr3:(Ce) detectors from the FATIMA collaboration. The detectors were arranged in an array of rhombicuboctahedron geometry, providing the possibility to carry out very precise angular correlation and directional-polarization correlation measurements. The triggerless acquisition system allowed a signal collection rate of up to 6 × 105 Hz. The data allowed to set multi-fold coincidences to obtain decay schemes and in combination with the FATIMA array of LaBr3:(Ce) detectors to analyze half-lives of excited levels in the pico- to microsecond range. Precise energy and efficiency calibrations of EXILL were performed using standard calibration sources of 133Ba, 60Co and 152Eu as well as data from the reactions 27Al(n,³)28Al and 35Cl(n,³)36Cl in the energy range from 30 keV up to 10 MeV.
Lalovic Natasa, Rudolph Dirk, Podolyak Zsolt, Sarmiento Luis, Simpson Edward C, Alexander Tom, Cortes Sua Martha Liliana, Gerl Juergen, Golubev Pavel, Ameil Frederic, Arici Tugba, Bauer Christopher, Bazzacco Dino, Bentley Michael A, Boutachkov Plamen, Bowry Michael, Fahlander Claes, Gadea Andres, Gellanki Jnaneswari, Givechev Angel, Goel Namita, Gorska M, Gottardo A., Gregor Eleonora, Guastalla Giulia, Habermann Tobias, Hackstein Mathias, Jungclaus A., Kojouharov Ivan, Kumar Rakesh, Kurz Nikolaus, Lettmann Marc, Lizarazo Cesar, Louchart-Henning Corinne, Merchan Edana, Michelagnoli Caterina, Moeller T, Moschner Kevin, Patel Zena, Pietralla Norbert, Pietri Stephane, Ralet Damian, Reese Michael, Regan Patrick, Reiter Peter, Schaffner Henning, Singh Pushpendra P, Stahl Christian, Stegmann Robert, Stézowski Olivier, Taprogge Jan, Thoele P, Wendt Andreas, Wieland Oliver, Wilson Emma, Wood Rachael, Wollersheim Hans-Juergen, Birkenbach Benedikt, Bruyneel Bart, Burrows Ian, Clement Emmanuel, Desesquelles Pierre, Domingo-Pardo Cesar, Eberth Juergen, Gonzales Millan Vicente, Hess Herbert, Jolie Jan, Judson Daniel, Menegazzo Roberto, Mengoni Daniele, Napoli Daniel, Pullia Alberto, Quintana Arnes Begona, Rainovski G I, Salsac Marie-Delphine, Sanchis Esteban, Simpson John, Valiente Dobón Jose Javier (2018) Study of Isomeric States in 198,200,202,206Pb and 206Hg Populated in Fragmentation Reactions,Journal of Physics G: Nuclear and Particle Physics45035105 IOP Publishing
Isomeric states in isotopes in the vicinity of doubly-magic 208Pb were
populated following reactions of a relativistic 208Pb primary beam impinging on a
9Be fragmentation target. Secondary beams of 198;200;202;206Pb and 206Hg were
isotopically separated and implanted in a passive stopper positioned in the focal
plane of the GSI Fragment Separator. Delayed ³ rays were detected with the
Advanced GAmma Tracking Array (AGATA). Decay schemes were re-evaluated
and interpreted with shell-model calculations. The momentum-dependent
population of isomeric states in the two-nucleon hole nuclei 206Pb/206Hg was
found to differ from the population of multi neutron-hole isomeric states in
198;200;202Pb.
The effect of competing ions on the sorption behaviour of uranium onto carboxyl-functionalised graphene oxide (COOH-GO) were studied in batch experiments in comparison to graphene oxide (GO) and graphite. The effect of increasing the abundance of select chemical functional groups, such as carboxyl groups, on the selectivity of U sorption was investigated. In the course of the study, COOH-GO demonstrated superior performance as a sorbent material for the selective removal of uranyl ions from aqueous solution with a distribution coefficient of 3.72 ± 0.19 × 103 mL g?1 in comparison to 3.97 ± 0.5 × 102 and 2.68 ± 0.2 × 102 mL g?1 for GO and graphite, respectively.
Tain J, Agramunt J, Ahn D, Algora A, Allmond J, Baba H, Bae S, Brewer N, Caballero Folch R, Calvino F, Coleman-Smith P, Cortes G, Davinson T, Dillmann I, Domingo-Pardo C, Estrade A, Fukuda N, Go S, Griffin C, Grzywacz R, Ha J, Hall O, Harkness-Brennan L, Isobe T, Kahl D, Karny M, Kiss G, Kogimtzis M, Korgul A, Kubono S, Labiche M, Lazarus I, Lee J, Liu J, Lorusso G, Matsui K, Miernik K, Montes F, Moon B, Morales A, Nepal N, Nishimura S, Page R, Podolyak Zsolt, Pucknell V, Rasco B, Regan Patrick, Riego A, Rubio B, Rykaczewski K, Saito Y, Sakurai H, Shimizu Y, Simpson J, Soderstrom P, Stracener D, Sumikama T, Surman R, Suzuki H, Takechi M, Takeda H, Tarifeno-Saldiva A, Thomas S, Tolosa-Delgado A, Phong V, Woods P (2018) The BRIKEN Project: Extensive Measurements of ²-delayed Neutron Emitters for the Astrophysical r Process,Acta Physica Polonica B49(3)pp. 417-428 Jagiellonian University
An ambitious program to measure decay properties, primarily ²-delayed
neutron emission probabilities and half-lives, for a significant number of
nuclei near or on the path of the rapid neutron capture process, has been
launched at the RIKEN Nishina Center. We give here an overview of the
status of the project.
Morales A.I., Benzoni G., Watanabe H., de Angelis G., Nishimura S., Coraggio L., Gargano A., Itaco N., Otsuka T., Tsunoda Y., Van Isacker P., Browne F., Daido R., Doornenbal P., Fang Y., Lorusso G., Patel Z., Rice S., Sinclair L., Söderström P.-A., Sumikama T., Valiente-Dobón J.J., Wu J., Xu Z.Y., Yagi A., Yokoyama R., Baba H., Avigo R., Bello Garrote F.L., Blasi N., Bracco A., Bruce A.M., Camera F., Ceruti S., Crespi F.C.L., Delattre M.-C., Dombradi Zs., Gottardo A., Isobe T., Kojouharov I., Kurz N., Kuti I., Lalkovski S, Matsui K., Melon B., Mengoni D., Miyazaki T., Modamio-Hoybjor V., Momiyama S., Napoli D.R., Niikura M., Orlandi R., Podolyak Zsolt, Regan Patrick, Sakurai H., Sahin E., Sohler D., Schaffner H., Taniuchi R., Taprogge J., Vajta Zs., Wieland O., Yalcinkaya M. (2018) Is seniority a partial dynamic symmetry in the first ½ g 9/2 shell?,Physics Letters B781pp. 706-712 Elsevier
The low-lying structures of the midshell ½g9/2 Ni isotopes 72Ni and 74Ni have been investigated at the RIBF facility in RIKEN within the EURICA collaboration. Previously unobserved low-lying states were accessed for the first time following ² decay of the mother nuclei 72Co and 74Co. As a result, we provide a complete picture in terms of the seniority scheme up to the first (8+) levels for both nuclei. The experimental results are compared to shell-model calculations in order to define to what extent the seniority quantum number is preserved in the first neutron g9/2 shell. We find that the disappearance of the seniority isomerism in the View the MathML source states can be explained by a lowering of the seniority-four (6+) levels as predicted years ago. For 74Ni, the internal de-excitation pattern of the newly observed View the MathML source state supports a restoration of the normal seniority ordering up to spin J=4. This property, unexplained by the shell-model calculations, is in agreement with a dominance of the single-particle spherical regime near 78Ni.
Koseoglou P., Werner V., Pietralla N., Ilieva S., Thürauf M., Bernards C., Blanc A., Bruce A. M., Cakirli R. B., Cooper N., Fraile L. M., de France G., Jentschel M., Jolie J., Koester U., Korten W., Kröll T., Lalkovski S., Mach H., M?rginean N., Mutti P., Patel Z., Paziy V., Podolyák Z., Regan P. H., Régis J.-M., Roberts O. J., Saed-Samii N., Simpson G. S., Soldner T., Ur C. A., Urban W., Wilmsen D., Wilson E. (2018) The boundary of the N=90 shape phase transition: 148Ce,Journal of Physics: Conference Series1023pp. 012022-1 IOP Publishing
The even-even N=90 isotones with Z=60-66 are known to undergo a first order phase transition. Such a phase transition in atomic nuclei is characterized by a sudden change of the shape of the nucleus due to changes in the location of the potential minimum. In these proceedings we report a measurement of the B4/2 ratio of 148Ce, which will probe the location of the low-Z boundary of the N=90 phase transitional region. The measured B4/2 value is compared to the prediction from the X(5) symmetry within the interacting boson model at the critical point between the geometrical limits of vibrators and rigid/axial rotors. The EXILL&FATIMA campaign took place at the high-flux reactor of the Institut Laue Langevin, Grenoble, were 235U and 241Pu fission fragments were measured by a hybrid spectrometer consisting of high-resolution HPGe and fast LaBr3(Ce)-scintillator detectors. The fast LaBr3(Ce) detectors in combination with the generalized centroid difference method allowed lifetime measurements in the picosecond region. Furthermore, this kind of analysis can serve as preparation for the FATIMA experiments at FAIR.
Sun Y, Zhang G, Watanabe H, Kondev F, Lane G, Regan P, Söderström P, Walker P, Kanaoka H, Korkulu Z, Lee P, Liu J, Nishimura S, Wu J, Yagi A, Ahn D, Alharbi T, Baba H, Browne F, Bruce A, Carroll R, Chae K, Dombradi Z, Doornenbal P, Estrade A, Fukuda N, Griffin C, Ideguchi E, Inabe N, Isobe T, Kanaya S, Kojouharov I, Kubo T, Kubono S, Kurz N, Kuti I, Lalkovski S, Lee C, Lee E, Lorusso G, Lotay G, Moon C, Nishizuka I, Nita C, Odahara A, Patel Z, Phong V, Podolyak Z, Roberts O, Sakurai H, Schaffner H, Shand C, Shimizu Y, Sumikama T, Suzuki H, Takeda H, Terashima S, Vajta Z, Valiente-Dóbon J, Xu Z (2018) ²-³ and isomeric decay spectroscopy of 168Dy,EPJ Web of Conferences178pp. 02023-1 - 02023-3 EDP Sciences
This contribution will report on the experimental work on the level structure of 168Dy. The experimental data have been taken as part of the EURICA decay spectroscopy campaign at RIBF, RIKEN in November 2014. In the experiment, a 238U primary beam is accelerated up to 345 MeV/u with an average intensity of 12 pnA. The nuclei of interest are produced by in-flight fission of 238U impinging on Be target with a thickness of 5 mm. The excited states of 168Dy have been populated through the decay from a newly identified isomeric state and via the ² decay from 168Tb. In this contribution, scientific motivations, experimental procedure and some preliminary results for this study are presented.
Heine M., Courtin S., Fruet G., Jenkins D.G., Morris L., Montanari D., Rudigier M., Adsley P., Curien D., Della Negra S., Lesrel J., Beck C., Charles L., Dené P., Haas F., Hammache F., Heitz G., Krauth M., Meyer A., Podolyak Zs., Regan P.H., Richer M., de Séréville N., Stodel C. (2018) The STELLA apparatus for particle-Gamma coincidence fusion measurements with nanosecond timing,Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment903pp. 1-7 Elsevier
The STELLA (STELlar LAboratory) experimental station for the measurement of deep sub-barrier light heavy-ion fusion cross sections has been installed at the Andromède accelerator at the Institut de Physique Nucléaire, Orsay (France). The setup is designed for the direct experimental determination of heavy-ion fusion cross sections as low as tens of picobarn. The detection concept is based on the coincident measurement of emitted gamma rays with the UK FATIMA (FAst TIMing Array) and evaporated charged particles using a silicon detector array. Key developments relevant to reaching the extreme sub-barrier fusion region are a rotating target mechanism to sustain beam intensities above 10¼A, an ultra-high vacuum of 10?8 mbar to prevent carbon built-up and gamma charged-particle timing in the order of nanoseconds sufficient to separate proton and alpha particles.
The work presented in this thesis details three aspects of determining absolute properties of nuclear decay data. The first facet is the design and commissioning of the NAtional Nuclear Array (NANA) for the use of primary standardisation of gamma-cascade emitting nuclides, and to be used more widely as a gamma-ray coincidence spectrometer. Geant4 Monte Carlo simulations were created to characterise possible designs, which were subsequently validated by comparing the response of the constructed array with the model. The simulation was also used to provide correction factors for the absolute standardisation of 60Co. The second strand concerns the determination of absolute emission probabilities of several gamma rays of the medically relevant radioisotope 153Gd. Measurements of these values were made using highly characterised HPGe detectors at the National Physical Laboratory.
The absolute gamma-ray emission probability of the 97.4~keV transition was found to be 30.15 (3) %, providing a new standard and correcting a possible discrepancy within the nuclear data of 153Gd reported by the Bureau Interntionale de Poids et Measures (BIPM) international reference system (SIR).
The final branch of the thesis presents analyses of beta minus decays of neutron-rich primary fission products created at the RIKEN Research Institute, Tokyo Japan.
Absolute beta-delayed gamma-ray emission probabilities and related
limits of the beta-delayed neutron emission probabilities have been deduced for 120-124Rh decays to Palladium isotopes and astrophysically important N=82 isotone, 129Ag to states in 128,129Cd.
Preliminary beta-delayed level schemes are presented for the daughter nuclei 120,122,124Pd as well as for the N=81, neutron-hole nucleus 129Cd.
The development of radionuclide standards for metrology has underpinned nuclear physics since its inception. The current frontier of radionuclide metrology relies on developments in radiation detection and signal processing combined with accurate nuclear decay data evaluations and contributes to a myriad of scientific disciplines. Radionuclide metrology represents a crucial part of the scientific jigsaw that enables societal benefits from nuclear physics research.-
Wiederhold J., Werner V., Kern R., Pietralla N., Bucurescu D., Carroll R., Cooper N, Daniel T., Filipescu D., Florea N., Gerst R-B., Ghita D., Gurgi Laila, Jolie J., Ilieva Ralitsa, Lica R., Marginean N., Marginean R., Mihai C., Mitu I. O., Naqvi F., Nita C., Rudigier Matthias, Stegemann S., Pascu S., Regan Patrick (2019) Evolution of E2 strength in the rare-earth isotopes Hf174,176,178,180,Physical Review C99(2) Mean lifetimes of yrast states of the isotopes 174,176,178,180Hf have been measured using fast- electronic scintillation timing. Excited states of 74,176,178Hf were populated via ² decay, while 180Hf was populated via Coulomb excitation. The lifetimes of the 2+
1 and 4+ 1 states of all isotopes and the lifetimes of the 6+ 1 states of 174,178Hf were measured, using the slope and the centroid shift methods. The mean lifetime, Ä (4+ 1 ) = 85(13) ps, of 178Hf has been determined for the first time. In addition, the mean lifetimes of the 2?
1 and the 3? 1 states of 176Hf have been determined. Systematic uncertainties on the evolution of data as a function of neutron number were reduced by using the same setup for all the isotopes of interest. The data are in agreement with other recent lifetime measurements where available and shows a shift of the maximum of collectivity for the Hf isotopic chain from neutron midshell at N = 104 to N = 100.
Berry T.A., Podolyak Zs., Carroll R.J., Lic? R., Grawe H., Timofeyuk N.K., Alexander T., Andreyev A.N., Ansari S., Borge M.J.G., Creswell J., Fahlander C., Fraile L.M., Fynbo H.O.U., Gelletly W., Gerst R.-B., Górska M., Gredley A., Greenlees P., Harkness-Brennan L.J., Huyse M., Judge S.M., Judson D.S., Konki J., Kurcewicz J., Kuti I., Lalkovski S., Lazarus I., Lund M., Madurga M., M?rginean N., M?rginean R., Marroquin I., Mihai C., Mihai R.E., Nácher E., Nae S., Negret A., Nic? C., Page R.D., Pascu S., Patel Z., Perea A., Pucknell V., Rahkila P., Rapisarda E., Regan P.H., Rotaru F., Shand C.M., Simpson E.C., Sotty Ch., Stegemann S., Stora T., Tengblad O., Turturica A., Van Duppen P., Vedia V., Wadsworth R., Walker P.M., Warr N., Wearing F., De Witte H. (2019) Investigation of the n = 0 selection rule in Gamow-Teller transitions: The ²-decay of 207Hg,Physics Letters B793pp. 271-275 Elsevier
Gamow-Teller ² decay is forbidden if the number of nodes in the radial wave functions of the initial and final states is different. This n=0 requirement plays a major role in the ² decay of heavy neutron-rich nuclei, affecting the nucleosynthesis through the increased half-lives of nuclei on the astrophysical r-process pathway below both Z=50 (for N à 82) and Z = 82 (for N à 126). The level of forbiddenness of the n=1v1g9/2 À0g7/2 transition has been investigated from the ² decay of the ground state of 207Hg into the single-proton-hole nucleus 207Tl in an experiment at the ISOLDE Decay Station. From statistical observational limits on possible ³-ray transitions depopulating the À0g-17/2 state in 207Tl, an upper limit of 3.9 x 10-3% was obtained for the probability of this decay, corresponding to log ft à 8.8 within a 95% confidence limit. This is the most stringent test of the n=0 selection rule to date.
Jovan
evi? N., Lebois M., Wilson J.N., Thisse D., Qi L., Matea I., Ibrahim F., Verney D., Babo M., Delafosse C., Adsley F., Tocabens G., Gottardo A., Popovitch Y., Nemer J., Canavan R., Rudigier M., Belvedere K., Boso A., Regan P., Podolyak Zs., Shearman R., Bunce M., Inavov P., Oberstedt S., Lopez-Martens A., Hauschild K., Ljungvall J., Chakma R., Lozeva R., Söderström P.-A., Oberstedt A., Etasse D., Ralet D., Blazhev A., Gerst R.-B., Hafner G., Cieplicka-OryDczak N., Iskra L., Fornal B., Benzoni G., Leoni S., Bottoni S., Henrich C., Koseoglou P., Wiederhold J., Homm I., Surder C., Kroll T., Knezevic D., Dragic A., Cortes L., Warr N., Miernik K., Adamska E., Piersa M., Rezynkina K., Fraile L., Benito Garcia J., Sanchez V., Algora A., Davies P., Guadilla-Gomez V., Fallot M., Kurtukian-Nieto T., Schmitt C., Heine M., Reygadas Tello D., Yavachova M., Diakaki M., Zeiser F., Paulson W., Gestvang D. (2019) Spectroscopy of neutron induced reactions with the -ball spectrometer,Acta Physica Polonica B50(3)pp. 297-304 Jagiellonian University
The -ball is a high-efficiency hybrid spectrometer which consists of
both germanium (Ge) detectors and associated anti-Compton BGO shields,
coupled to lanthanum bromide (LaBr3) detectors. The hybrid configuration
provides a combination of both excellent energy and timing resolutions.
The -ball geometry allows the coupling with the LICORNE directional
neutron source at the ALTO facility of the IPN, Orsay. This opens the
possibility to perform precise spectroscopy of neutron induced reactions
and was used for two experiments during the recent experimental campaign.
These two experiments are described here: 1. Spectroscopy of the
neutron-rich fission fragments produced in the 238U(n; f) and 232Th(n; f)
reactions; 2. Spectroscopy above the shape isomer in 238U. The 238U(n; f)
and 232Th(n; f) reactions produce hundreds of neutron-rich nuclei on which
gamma-ray spectroscopy can be performed. The main goal of the experiment
aiming to populate the shape isomer in 238U is the measurement of
the gamma-ray and fission decay branches as well as determination of level
scheme in the super-deformed minimum. The shape isomer is populated
by 238U(n; n') reaction, which gives a very advantageous population cross
section over other reactions. More detailed descriptions of these two -ball
experiments will be presented here.
Rudigier M., Canavan R.L., Regan P.H., Söderström P.-A., Lebois M., Wilson J.N., Jovancevic N., Bottoni S., Brunet M., Cieplicka-Orynczak N., Courtin S., Doherty D.T., Hadynska-Klek K., Heine M., Iskra W., Karayonchev V., Kennington A., Koseoglou P., Lotay G., Lorusso G., Nakhostin M., Nita C.R., S. Oberstedt S., Podolyak Zs., Qi L., Régis J.-M., Shearman R., Walker P.M., Witt W. (2019) Isomer spectroscopy and sub-nanosecond half-live determination in 178w using the NuBall array,Acta Physica Polonica B50(3)pp. 661-667 Jagiellonian University
The reaction of a pulsed 18O beam on a 164Dy target was studied in
the first experiment with the NuBall array at the IPN Orsay, France. Excited
state half-lives were measured using the fast timing method with 20
LaBr3(Ce) detectors. The timing characteristics of the fully digital acquisition
system is briefly discussed. A value for the previously unknown
half-life of the first excited 4+ state in 178W is presented.
Gottardo A., Valiente-Dobón J. J., Benzoni G., Morales A. I., Gadea A., Lunardi S., Boutachkov P., Bruce A. M., Górska M., Grebosz J., Pietri S., Podolyak Zs., Pfützner M., Regan P. H., Rudolph D., Weick H., Alcántara Núñez J., Algora A., Al-Dahan N., de Angelis G., Ayyad Y., Alkhomashi N., Allegro P. R. P., Bazzacco D., Benlliure J., Bowry M., Bracco A., Bunce M., Camera F., Casarejos E., Cortes M. L., Crespi F. C. L., Corsi A., Denis Bacelar A. M., Deo A. Y., Domingo-Pardo C., Doncel M., Dombradi Zs., Engert T., Eppinger K., Farrelly G. F., Farinon F., Geissel H., Gerl J., Goel N., Gregor E., Habermann T., Hoischen R., Janik R., Klupp S., Kojouharov I., Kurz N., Lenzi S. M., Leoni S., Mandal S., Menegazzo R., Mengoni D., Million B., Napoli D. R., Naqvi F., Nociforo C., Prochazka A., Prokopowicz W., Recchia F., Ribas R. V., Reed M. W., Sahin E., Schaffner H., Sharma A., Sitar B., Siwal D., Steiger K., Strmen P., Swan T. P. D., Szarka I., Ur C. A., Walker P.M., Wieland O., Wollersheim H-J., Nowacki F., Maglione E. (2019) New spectroscopic information on 211;213Tl A changing structure beyond the N=126
shell closure,Physical Review C99(5)pp. 054326-1 American Physical Society
The neutron-rich isotopes 211;213Tl, beyond the N = 126 shell-closure, have been studied for the first time in isomer ³-ray decay, exploiting the fragmentation of a primary uranium beam at the FRS-RISING (FRagment Separator-Rare ISotopes INvestigation at GSI) setup at GSI. The
observed isomeric states in 211;213Tl show a deviation from the seniority-like scheme of 209Tl. The possible interpretation of the data is discussed on the basis of energy-level systematics and shell-model calculations.
The safe decommissioning of nuclear reactors, worldwide, is a major challenge facing the nuclear industry. Operational activities associated with nuclear decommissioning are expected to generate large volumes of high-level aqueous nuclear waste. Therefore, there is a growing need to develop new treatment processes. Previous work has shown nanomaterials are effective sorption materials for radionuclide removal. However, minimal research has been carried out on hybrid sorption materials consisting of selective functional groups and carbon-based nanomaterials. In this research, functionalised multi-walled carbon nanotubes (MWCNTs) and graphene oxide (GO), were prepared for the removal of long-lived radionuclides, namely, uranium (U(VI)) from aqueous solution. A series of synthesis procedures were applied to unmodified forms of MWCNTs and GO to enhance selectivity towards U(VI). This was accomplished by attaching surface complexing functional groups, such as, COOH, OH and CONH, onto the surface of the nanomaterial. For this work, chemical functionalisation was confirmed by Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The former technique involved monitoring the ratio of the Raman D and G bands (ID/IG), before and after functionalisation, via statistical Raman mapping studies. Overall, an increase in the ID/IG ratio was observed for each functionalised material. This suggests that the chemical functionalisation procedure applied to unmodified MWCNTs and GO materials was successful in introducing an increased number of defect sites suitable for the attachment of functional groups. This finding was further supported by high resolution XPS studies, which confirmed the presence of select surface groups of interest onto each material. The sorption behaviour of functionalised MWCNTs and GO materials towards U(VI) was investigated in the form of batch sorption studies with solution analysis by inductively coupled plasma mass spectrometry (ICP-MS). The following parameters, which are known to influence sorption behaviour were investigated, namely, the effect of pH, contact time and competing ions (Mg, Co, Zn, Sr, Pb and Th). This was done to assess the suitability of each material for nuclear waste treatment. Initial studies revealed that functionalised MWCNTs had minimal selectivity and loading capacity (Qmax) for U(VI) in aqueous solution. The results showed for the best-performing MWCNTs material (COOH-f MWCNTs), the U sorption and the distribution co-efficient (Kd) decreased, in the presence of competing ions from 97.4 ± 1.6 to 12.6 ± 1.0 % and 3.1×104 to 1.4×102 mL g-1, respectively. Moreover, a Qmax of 34.01 mg g-1 was observed for COOH-f MWCNTs under optimal pH conditions. In terms of all the sorption materials tested, COOH-f GO, exhibited the highest selectivity (Kd of 3.7×103 mL g-1) for U(VI) in aqueous solution with a Qmax of 169.20 mg g?1. The sorption performance of COOH-f GO was tested using a high salinity aqueous nuclear waste sample (Sellafield, UK), which showed minimal selectivity for uranium (Kd of 1.0×102 mL g-1) even after pH-adjustment. Furthermore, a higher affinity for competing ions was observed with 85.0 ± 6.9 %, 82.5 ± 5.2 % and 87.5 ± 4.9 % of Mg, Sr and Pb removed by COOH-f GO. The effect of combining the high sorption capacity of COOH-f GO for uranium with magnetic separation (i.e. Fe3O4-f GO) was investigated by batch sorption studies using sequentially-extracted soil samples from the Laguna Sirven Deposit, Santa Cruz, Argentina. Overall, the results showed that Fe3O4-f GO can remove up to 86.7 ± 2.3 % of uranium from sample matrices relevant to uranium remediation. As such, the research described in this thesis could potentially find use in many future applications, including nuclear decommissioning and environmental remediation studies.
Spagnoletti P., Simpson G., Kisyov S., Bucurescu D., Régis J.-M., Saed-Samii N., Blanc A., Jentschel M., Köster U., Mutti P., Soldner T., de France G., Ur C. A., Urban W., Bruce A. M., Bernards C., Drouet F., Fraile L. M., Gaffney L. P., Ghit? D. G., Ilieva S., Jolie J., Korten W., Kröll T., Lalkovski S., Larijarni C., Lic? R., Mach H., M?rginean N., Paziy V., Podolyak Zs., Regan P. H., Scheck M., Smith J. F., Thiamova G., Townsley C., Vancraeyenest A., Vedia V., Warr N., Werner V., ZieliDska M. (2019) Lifetimes and shape-coexisting states of 99Zr,Physical Review C100(1)014311pp. 014311-1 American Physical Society
Lifetimes of intermediate-spin states in two rotational bands of 99Zr have been measured. These states were populated following the neutron-induced fission of 235U at the PF1B beamline of the Institut Laue-Langevin, Grenoble, during the EXILL-FATIMA campaign. The nucleus 99Zr59 exhibits shape coexistence and lies precisely on the border of an abrupt change in ground-state deformation when going from N=58 to N=60, making its study interesting for understanding the mechanisms involved in the rapid onset of deformation here. The B(E2) values extracted for decays in the ½3/2[541] band allow quadrupole deformations of ²2=0.34(1) and 0.26(3) to be determined for the 821.6- and 1236.6-keV members, whereas ²2=0.32(3) was found for the 850.5-keV member of the ½3/2[411]band. Some of the excited states known in 99Zr have been reasonably described with interacting boson-fermion model (IBFM) calculations. Type-II shell evolution is proposed to play a major role in modifying single-particle energies in 99Zr.
Phong V. H., Lorusso G., Davinson T., Estrade A., Hall O., Liu J., Matsui K., Montes F., Nishimura S., Boso A., Regan P. H., Shearman R., Xu Z. Y., Agramunt J., Allmond J. M., Ahn D. S., Algora A., Baba H., Brewer N. T., Bruno C. G., Caballero-Folch R., Calvino F., WoliDska-Cichocka M., Cortes G., Dillmann I., Domingo-Pardo C., Gargano A., Go S., Griffin C. J., Grzywacz R. K., Harkness-Brennan L., Isobe T., Jungclaus A., Kahl D., Khiem L. H., Kiss G., Korgul A., Kubono S., Miernik K., Morales A. I., Nepal N., Piersa M., Podolyak Zs., Rasco B. C., Rykaczewski K. P., Sakurai H., Shimizu Y., Stacener D. W., Sumikama T., Suzuki H., Takeda H., Tain J. L., Tarifeño-Saldivia A., Tolosa-Delgado A., Vaquero V., Woods P. J., Yokoyama R., Yuan C. (2019) Observation of a ¼s isomer in ¹³tIn
: Proton-neutron coupling "southeast" of ¹³²
Sn,Physical Review C100011302(R)pp. 011302-1 American Physical Society
We report on the observation of a microsecond isomeric state in the single-proton-hole, three-neutron-particle nucleus ¹³tIn. The nuclei of interest were produced by in-flight fission of a ²³xU beam at the Radioactive Isotope Beam Factory at RIKEN. The isomer depopulates through a ³ ray of energy 56.7(1) keV and with a half-life of T1/2=3.5(4)¼s. Based on the comparison with shell-model calculations, we interpret the isomer as the IÀ=5? member of the À0g?19/2½1f37/2 multiplet, decaying to the IÀ=7? ground state with a reduced-transition probability of B(E2;5?7?)=0.53(6)W.u.Observation of this isomer, and lack of evidence in the current work for a IÀ=5? isomer decay in ¹³²In, provides a benchmark of the proton-neutron interaction in the region of the nuclear chart ?southeast? of ¹³²Sn, where experimental information on excited states is sparse.
Gamba E. R., Bruce A. M., Lalkovski S., Rudigier M., Bottoni S., Carpenter M. P., Zhu S., Anderson J. T., Ayangeakaa A. D., Berry T. A., Burrows I., Gallardo M. Carmona, Carroll R. J., Copp P., Cullen D. M., Daniel T., Martínez G. Fernández, Greene J. P., Gurgi L. A., Hartley D. J., Ilieva R., Ilieva S., Kondev F. G., Kröll T., Lane G. J., Lauritsen T., Lazarus I., Lotay G., Nic? C. R., Podolyak Zs., Pucknell V., Reed M., Regan P. H., Rohrer J., Sethi J., Seweryniak D., Shand C. M., Simpson J., SmoleD M., Stefanova E. A., Vedia V., Yordanov O. (2019) Fast-timing measurements in the ground-state band of ¹¹tPd,Physical Review C100(4)044309pp. 044309-1 American Physical Society
Using a hybrid Gammasphere array coupled to 25 LaBr3(Ce) detectors, the lifetimes of the first three levels of the yrast band in ¹¹tPd populated via ²u²Cf decay, have been measured. The measured lifetimes are Ä+=103(10)ps, Ä+=22(13)ps, and Ä+d10ps for the 2z, 4z, and 6z levels, respectively. Palladium-114 was predicted to be the most deformed isotope of its isotopic chain, and spectroscopic studies have suggested it might also be a candidate nucleus for low-spin stable triaxiality. From the lifetimes measured in this work, reduced transition probabilities B(E2;JJ?2) are calculated and compared with interacting boson model, projected shell model, and collective model calculations from the literature. The experimental ratio RB(E)=B(E2;4z2z)/B(E2;2z0z)=0.80(42) is measured for the first time in ¹¹tPd and compared with the known values RB(E) in the palladium isotopic chain: the systematics suggest that, for N=68, a transition from ³-unstable to a more rigid ³-deformed nuclear shape occurs.
Zhang G.X., Watanabe H., Dracoulis G.D., Kondev F.G., Lane G.J., Regan P.H., Söderström P.-A., Walker P.M., Yoshida K., Kanaoka H., Korkulu Z., Lee P.S., Liu J.J., Nishimura S., Wu J., Yagi A., Ahn D.S., Alharbi T., Baba H., Browne F., Bruce A.M., Carpenter M.P., Carroll R.J., Chae K.Y., Chiara C.J., Dombradi Zs., Doornenbal P., Estrade A., Fukuda N., Griffin C., Ideguchi E., Inabe N., Isobe T., Kanaya S., Kojouharov I., Kubo T., Kubono S., Kurz N., Kuti I., Lalkovski S., Lauritsen T., Lee C.S., Lee E.J., Lister C.J., Lorusso G., Lotay G., McCutchan E.A., Moon C.-B., Nishizuka I., Nita C.R., Odahara A., Patel Z., Phong V.H., Podolyak Zs., Roberts O.J., Sakurai H., Schaffner H., Seweryniak D., Shand C.M., Shimizu Y., Sumikama T., Suzuki H., Takeda H., Terashima S., Vajta Zs., Valiente-Dóbon J.J., Xu Z.Y., Zhu S. (2019) Interplay of quasiparticle and vibrational excitations: First observation of isomeric states in ¹vxDy and ¹vyDy,Physics Letters B799135036pp. 1-7 Elsevier
The neutron-rich dysprosium isotopes ¹vxDy and ¹vyDy have been investigated using the EURICA ³-ray spectrometer, following production via in-flight fission of a high-intensity uranium beam in conjunction with isotope separation through the BigRIPS separator at RIBF in RIKEN Nishina Center. For ¹vxDy, a previously unreported isomer with a half-life of 0.57(7) ¼s has been identified at an excitation energy of 1378 keV, and its presence affirmed independently using ³-³-³ coincidence data taken with Gammasphere via two-proton transfer from an enriched ¹wpEr target performed at Argonne National Laboratory. This isomer is assigned JÀ = KÀ = (4{) based on the measured transition strengths, decay patterns, and the energy systematics for two-quasiparticle states in N = 102 isotones. The underlying mechanism of two-quasiparticle excitations in the doubly midshell region is discussed in comparison with the deformed QRPA and multi-quasiparticle calculations. In ¹vyDy, the B(E2) value for the transition de-exciting the previously unreported KÀ = (1/2{) isomeric state at 166 keV to the KÀ = (5/2{) ground state is approximately two orders of magnitude larger than the E2 strength for the corresponding isomeric-decay transition in the N = 103 isotone ¹w³Yb, suggesting the presence of a significant ³-vibrational admixture with a dominant neutron one-quasiparticle component in the isomeric state.
Rudigier M., Walker P. M., Canavan R.L., Podolyak Zs., Regan P. H., Söderström P.-A., Lebois M., Wilson J.N., Jovancevic N., Blazhev A., Benito J., Bottoni S., Brunet M., Cieplicka-Orynczak N., Courtin S., Doherty D. T., Fraile L.M., Hadynska-Klek K., Heine M., Iskra A.W., Jolie J., Karayonchev V., Kennington A. R., Koseoglou P., Lotay G., Lorusso G., Nakhostin M., Nita C.R., Oberstedt S., Qi L., Régis J.-M., Sánchez-Tembleque V., Shearman R., Witt W., Vedia V., Zell K.O. (2020) Multi-quasiparticle sub-nanosecond isomers in 178W,Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics801135140 Elsevier
We report on the first measurement of the half-lives of and four-quasiparticle states in the even-even nucleus 178W. The sub-nanosecond half-lives were measured by applying the centroid shift method to data taken with LaBr3(Ce) scintillator detectors of the NuBall array at the ALTO facility in Orsay, France. The half-lives of these states only became experimentally accessible by the combination of several experimental techniques - scintillator fast timing, isomer spectroscopy with a pulsed beam, and the event-by-event calorimetry information provided by the NuBall array. The measured half-lives are and for the and states, respectively. The decay transitions include weakly hindered E1 and E2 branches directly to the ground-state band, bypassing the two-quasiparticle states. This is the first such observation for an E1 transition. The interpretation of the small hindrance hinges on mixing between the ground-state band and the t-band.
Koseoglou P., Werner V., Pietralla N., Ilieva S., Nikai? T., Vretenar D., Alexa P., Thqrauf M., Bernards C., Blanc A., Bruce A. M., Cakirli R. B., Cooper N., Fraile L. M., de France G., Jentschel M., Jolie J., KQster U., Korten W., KrQll T., Lalkovski S., Mach H., M?rginean N., Mutti P., Patel Z., Paziy V., Podolyak Zs., Regan Patrick, Régis J.-M., Roberts O. J., Saed-Samii N., Simpson G. S., Soldner T., Ur C. A., Urban W., Wilmsen D., Wilson E. (2020) Low-Z boundary of the N = 88-90 shape phase transition: 148Ce near the critical point,Physical Review C101(1)014303 American Physical Society
Excited states of the neutron-rich nucleus 148Ce have been populated by neutron-induced fission of 235U and 241Pu samples. Their electromagnetic decays were studied by means of ³-ray coincidence spectroscopy with fast-timing capabilities. Lifetimes of the 2+1 and 4+1 states of 148Ce were obtained
and their E2 decay rates deduced. The B4=2 = B(E2; 4+1 2+1)=B(E2; 2+1 0+1) ratio indicates that 148Ce is a transitional nucleus while the N = 88/90 shape phase transition evolves into a gradual change of nuclear deformation for proton numbers Z < 60.
Rudigier M., Podolyak Zs., Regan P.H., Bruce A.M., Lalkovski S., Canavan R.L., Gamba E.R., Roberts O., Burrows I., Cullen D.M., Fraile L.M., Gerhard L., Gerl J., Gorska M., Grant A., Jolie J., Karayonchev V., Kurz N., Korten W., Lazarus I.H., Nita C.R., Pucknell V.F.E., Régis J.-M., Schaffner H., Simpson J., Singh P., Townsley C.M., Smith J.F., Vesic J. (2020) FATIMA ? FAst TIMing Array for DESPEC at FAIR,Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment969163967 Elsevier
The components, working principle and characteristics of FATIMA (FAst TIMing Array), a fast-timing detector system for DESPEC at FAIR, are described. The core system includes 36 LaBr3(Ce) scintillator detectors, a mounting frame for the DESPEC station and a VME-based fast-timing data acquisition system. The current electronic timing circuit is based on V812 constant fraction discriminators and V1290 time-to-digital converters. Gamma-ray energies are measured using V1751 digitisers. Characteristics of the core FATIMA system including efficiency, energy, and coincidence resolving time, as well as limitations, are discussed on the basis of test measurements performed in the S4 cave at GSI, Germany. The coincidence ³-³ time resolution for the prompt 60Co cascade is determined to be ~320 ps full width at half maximum. The total full energy peak efficiency at 1 MeV for the 36 detector array in the DESPEC setup is 2.9%. The energy-dependent prompt response centroid curve with the current CFD/TDC combination is shown to be smooth; the centroid shift method can be applied for the measurement of half-lives below 200 ps. An overview of applications of the FATIMA detectors as an ancilliary system in combination with other detector arrays during recent years is given. Data on the operation of the detectors in the presence of magnetic fields are presented.
Ha J., Sumikama T., Browne F., Hinohara N., Bruce A. M., Choi S., Nishizuka I., Nishimura S., Doornenbal P., Lorusso G., Söderström P.-A., Watanabe H., Daido R., Patel Z., Rice S., Sinclair L., Wu J., Xu Z. Y., Yagi A., Baba H., Chiga N., Carroll R., Didierjean F., Fang Y., Fukuda N., Gey G., Ideguchi E., Inabe N., Isobe T., Kameda D., Kojouharov I., Kurz N., Kubo T., Lalkovski S., Li Z., Lozeva R., Nishibata H., Odahara A., Podolyak Zs., Regan P. H., Roberts O. J., Sakurai H., Schaffner H., Simpson G. S., Suzuki H., Takeda H., Tanaka M., Taprogge J., Werner V., Wieland O. (2020) Shape evolution of neutron-rich 106,108,110Mo isotopes in the triaxial degree of freedom,Physical Review C101(4)044311 American Physical Society
Background: Neutron-rich nuclei with mass number between 100 and 110 attract much attention, since several kinds of shapes, such as spherical, prolate, oblate, and triaxial shapes, are predicted. In particular, for neutron-rich Mo isotopes, different models predict different magnitudes and rigidity of triaxial deformation. Previous interpretations of experimental results based solely on low-lying
2+2 states are insufficient to distinguish between the rigid triaxial shape,
³ vibration, or
³
-soft rotor.
Purpose: The shape evolution of 106Mo, 108Mo, and 110Mo is investigated through their
2+1-state lifetimes, decay-branching ratios of the
2+2 state, and energies of the low-lying collective excited states with
KÀ =
0+,
2+, and
4+.
Method:
²
-delayed
³
-ray spectroscopy was employed for neutron-rich Nb and Zr isotopes produced at the RIKEN RI Beam Factory to populate excited states in 106Mo
, 108Mo
, and 110Mo
. The EUroball-RIKEN Cluster Array was used for high-resolution
³
-ray detection and lifetimes of the
2+1 states were determined using the UK fast-timing array of
LaBr3(Ce) detectors.
Results: New
³
-ray transitions and levels are reported, including newly assigned
0+2 states in 108,110Mo
. Quadrupole deformations were obtained for 106,108,110Mo from their
2+1 energies and lifetimes. The
²
-delayed neutron-emission probabilities of
108
Nb and
110
Nb were determined by examining the
³ rays of their respective daughter decays.
Conclusions: The even-odd energy staggering in the
2+2 band was compared with typical patterns of the
³
-vibrational band, rigid triaxial rotor, and
³
-soft rotor. The very small even-odd staggering of 106Mo, 108Mo, and 110Mo favors a
³
-vibrational band assignment. The kinematic moment of inertia for the
2+2 band showed a trend similar to the ground-state band, which is as expected for the
³
-vibrational band. Beyond-mean-field calculations employing the constrained Hartree-Fock-Bogoliubov and local quasiparticle-random-phase approximation method using the
SLy
5
+
T interaction reproduced the ground and
2+2 bands in 106Mo and 108Mo
. The collective wave functions are consistent with the interpretation of the
2+2 band as the
³
-vibrational band of the prolate shape. However, the staggering pattern observed in 110Mo differs from the one suggested in the calculations which predict a
³
-soft rotor. There was no experimental indication of the oblate shape or the
³
-soft rotor predicted in these Mo isotopes.
Berry T. A., Podolyak Zs., Carroll R. J., Lic? R., Brown B. A., Grawe H., Sotty Ch., Timofeyuk N. K., Alexander T., Andreyev A. N., Ansari S., Borge M. J. G., Brunet M., Cresswell J. R., Fahlander C., Fraile L. M., Fynbo H. O. U., Gamba E., Gelletly W., Gerst R.-B., Górska M., Gredley A., Greenlees P., Harkness-Brennan L. J., Huyse M., Judge S. M., Judson D. S., Konki J., Kowalska M., Kurcewicz J., Kuti I., Lalkovski S., Lazarus I., Lund M., Madurga M., M?rginean N., M?rginean R., Marroquin I., Mihai C., Mihai R. E., Nácher E., Negret A., Nae S., Nic? C., Pascu S., Page R. D., Patel Z., Perea A., Phrompao J., Piersa M., Pucknell V., Rahkila P., Rapisarda E., Regan P. H., Rotaru F., Rudigier M., Shand C. M., Shearman R., Simpson E. C., Stegemann S., Stora T., Tengblad O., Turturica A., Van Duppen P., Vedia V., Walker P. M., Warr N., Wearing F. P., De Witte H. (2020) Octupole states in 207Tl studied through ² decay,Physical Review C101(5)054311 American Physical Society
The ² decay of 207Hg into the single-proton-hole nucleus 207Tl has been studied through ³-ray spectroscopy at the ISOLDE Decay Station (IDS) with the aim of identifying states resulting from coupling of the Às?11/2, Àd?13/2, and Àh?111/2 shell model orbitals to the collective octupole vibration. Twenty-two states were observed lying between 2.6 and 4.0 MeV, eleven of which were observed for the first time, and 78 new transitions were placed. Two octupole states (s1/2-coupled) are identified and three more states (d3/2-coupled) are tentatively assigned using spin-parity inferences, while further h11/2-coupled states may also have been observed for the first time. Comparisons are made with state-of-the-art large-scale shell model calculations and previous observations made in this region, and systematic underestimation of the energy of the octupole vibrational states is noted. We suggest that in order to resolve the difference in predicted energies for collective and noncollective t=1 states (t is the number of nucleons breaking the 208Pb core), the effect of t=2 mixing may be reduced for octupole-coupled states. The inclusion of mixing with t=0,2,3 excitations is necessary to replicate all t=1 state energies accurately.
Fruet G., Courtin S., Heine M., Jenkins D. G., Adsley P., Brown A., Canavan R., Catford W. N., Charon E., Curien D., Della Negra S., Duprat J., Hammache F., Lesrel J., Lotay G., Meyer A., Montanari D., Morris L., Moukaddam M., Nippert J., Podolyak Zs., Regan P. H., Ribaud I., Richer M., Rudigier M., Shearman R., de Séréville N., Stodel C. (2020) Advances in the Direct Study of Carbon Burning in Massive Stars,Physical Review Letters124192701 American Physical Society
The 12C + 12C fusion reaction plays a critical role in the evolution of massive stars and also strongly impacts various explosive astrophysical scenarios. The presence of resonances in this reaction at energies around and below the Coulomb barrier makes it impossible to carry out a simple extrapolation down to the Gamow window?the energy regime relevant to carbon burning in massive stars. The 12C + 12C system forms a unique laboratory for challenging the contemporary picture of deep sub-barrier fusion (possible sub-barrier hindrance) and its interplay with nuclear structure (sub-barrier resonances). Here, we show that direct measurements of the 12C + 12C fusion cross section may be made into the Gamow window using an advanced particle-gamma coincidence technique. The sensitivity of this technique effectively removes ambiguities in existing measurements made with gamma ray or charged-particle detection alone. The present cross-section data span over 8 orders of magnitude and support the fusion-hindrance model at deep sub-barrier energies.
GBL15, the UK?s noble gas certified Comprehensive Nuclear-Test-Ban Treaty (CTBT) radionuclide laboratory supports the International Monitoring System (IMS) through measurement of environmental radioxenon samples using coincidence spectrometry. GBL15 currently utilises a system comprised of NaI(Tl) -detectors and plastic scintillator -detectors to measure coincident emissions from the four radioxenon isotopes of interest: Xe, Xe, Xe and Xe. This paper reports on the setup, calibration and assessment of the CEA/Mirion-developed PIPSBox, used in coincidence setup with a high-purity germanium detector. The system has been configured to measure the signals from the four radionuclides of interest and demonstrates improved discrimination between signals and less interference compared to the current system. The coincident detection efficiencies are quantified through measurement of spiked radioxenon samples.