Professor Wilton Catford


Professor, Research Group Leader of Experimental Nuclear Physics
+44 (0)1483 686804
04 BC 04

Academic and research departments

Experimental Nuclear Physics Group.

Biography

Research

Research interests

My publications

Publications

M. C. Parker, C. Jeynes, W. N. Catford (2022)Halo Properties in Helium Nuclei from the Perspective of Geometrical Thermodynamics, In: Annalen der Physik534(2) Wiley

The nuclear matter and charge radii of the helium isotopes (A=4,6,8) are calculated by quantitative geometrical thermodynamics (QGT) taking as input the symmetry of the alpha-particle, the very weak binding (and hence halo nature) of the heavier helium isotopes, and a characteristic length scale given by the proton size. The results follow by considering each isotope in its ground state, with QGT representing each system as a maximum entropy configuration that conforms to the Holographic Principle. This allows key geometric parameters to be determined from the number of degrees of freedom available. QGT treats 6He as a 4He core plus a concentric neutron shell comprising a holomorphic pair of neutrons, and the 8He neutron halo is treated as a holomorphic pair of holomorphic pairs. Considering that the information content of each system allows a correlation angle of 2/3 between the holomorphic entities to be inferred, then the charge radii of the three isotopes can be calculated from the displacement of the 4He core from the centre of mass. The calculations for the charge and matter radii of 4,6,8He agree closely with observed values. Similar QGT calculation of the sizes of the self-conjugate A=4n nuclei {4He, 8Be, 12C, 16O, 20Ne, 24Mg, 28Si, 32S, 36Ar, 40Ca} also agree well with experiment.

GAVIN JAMES LOTAY, S. A. Gillespie, MARIE WILLIAMS, T Rauscher, M Alcorta, M Amthor, C. Andreoiu, D Baal, G. C. Ball, S. S Bhattacharjee, H Behnamian, V Bildstein, C. Burbadge, WILTON NEIL CATFORD, DANIEL THOMAS DOHERTY, N. E Esker, F. H. Garcia, A. B. Garnsworthy, G. Hackman, K Hudson, SAMUEL JAMES HALLAM, SHAHEEN JAZRAWI, E Kasanda, ADAM RUSSELL KENNINGTON, YOUNGCHAN KIM, A. Lennarz, R. S Lubna, C. R Natzke, N Nishimura, B Olaizola, Charlie Paxman, A Psaltis, C. E. Svensson, J Williams, B Wallis, D Yates, D Walter, Davids B (2021)First Direct Measurement of an Astrophysical p-Process Reaction Cross Section Using a Radioactive Ion Beam, In: Physical review letters127(11)pp. 1-112701 APS

Physical Review Letters 127, 112701 (2021) We have performed the first direct measurement of the 83Rb(p,g) radiative capture reaction cross section in inverse kinematics using a radioactive beam of 83Rb at incident energies of 2.4 and 2.7 A MeV. The measured cross section at an effective relative kinetic energy of Ecm = 2.393 MeV, which lies within the relevant energy window for core collapse supernovae, is smaller than the prediction of statistical model calculations. This leads to the abundance of 84Sr produced in the astrophysical p process being higher than previously calculated. Moreover, the discrepancy of the present data with theoretical predictions indicates that further experimental investigation of p-process reactions involving unstable projectiles is clearly warranted.

LAETITIA CANETE, GAVIN JAMES LOTAY, G. Christian, DANIEL THOMAS DOHERTY, WILTON NEIL CATFORD, SAMUEL JAMES HALLAM, D. Seweryniak, H.M Albers, S Almaraz-Calderon, E.A Bennett, M.P. Carpenter, C.J. Chiara, JP Greene, C Hoffman, R. V. F. Janssens, J Jose, A Kankainen, T. Lauritsen, S Ota, A. Matta, A Saastamoinen, Ryan Wilkinson, M. Moukaddam, S. Zhu (2021)New constraints on the Al 25 ( p , γ ) reaction and its influence on the flux of cosmic γ rays from classical nova explosions, In: Physical review. C104L022802 American Physical Society (APS)

The astrophysical 25Al(p,γ) 26Si reaction represents one of the key remaining uncertainties in accurately modeling the abundance of radiogenic 26Al ejected from classical novae. Specifically, the strengths of key proton-unbound resonances in 26Si, that govern the rate of the 25Al(p,γ) reaction under explosive astrophysical conditions, remain unsettled. Here, we present a detailed spectroscopy study of the 26Si mirror nucleus 26Mg. We have measured the lifetime of the 3+, 6.125-MeV state in 26Mg to be 19(3) fs and provide compelling evidence for the existence of a 1– state in the T = 1, A = 26 system, indicating a previously unaccounted for ℓ = 1 resonance in the 25Al(p,γ) reaction. Using the presently measured lifetime, together with the assumption that the likely 1– state corresponds to a resonance in the 25Al + p system at 435.7(53) keV, we find considerable differences in the 25Al(p,γ) reaction rate compared to previous works. Furthermore, based on current nova models, we estimate that classical novae may be responsible for up to ≈ 15% of the observed galactic abundance of 26Al.

S Ota, G Christian, W. N Catford, G Lotay, M Pignatari, J. A Tostevin, U Battino, E. A Bennett, S Dede, D. T Doherty, S Hallam, F Herwig, J Hooker, C Hunt, H Jayatissa, A Matta, M Moukaddam, E Rao, G. V Rogachev, A Saastamoinen, D Scriven, S Upadhyayula, R Wilkinson (2021)(6Li, d) and (6Li, t) reactions on 22Ne and implications for s-process nucleosynthesis, In: Physical Review C104055806 American Physical Society

We studied α cluster states in 26Mg via the 22Ne(6Li,dγ)26Mg reaction in inverse kinematics at an energy of 7 MeV/nucleon. States between Ex = 4–14 MeV in 26Mg were populated and relative α spectroscopic factors were determined. Some of these states correspond to resonances in the Gamow window of the 22Ne(α,n)25Mg reaction, which is one of the main neutron sources in the astrophysical s-process. Using our new 22Ne(α,n)25Mg and 22Ne(α,γ)26Mg reaction rates, we performed new s-process calculations for massive stars and asymptotic giant branch stars and compared the resulting abundances with the abundances obtained using other 22Ne+α rates from the literature. We observe an impact on the s-process abundances up to a factor of three for intermediate-mass AGB stars and up to a factor of ten for massive stars. Additionally, states in 25Mg at Ex < 7.5 MeV are identified via the 22Ne(6Li,t)25Mg reaction for the first time. We present the (6Li, t) spectroscopic factors of these states and note similarities to the (d,p) reaction in terms of reaction selectivity.

M Grieser, YA Litvinov, R Raabe, K Blaum, Y Blumenfeld, PA Butler, F Wenander, PJ Woods, M Aliotta, A Andreyev, A Artemyev, D Atanasov, T Aumann, D Balabanski, A Barzakh, L Batist, A-P Bernardes, D Bernhardt, J Billowes, S Bishop, M Borge, I Borzov, F Bosch, AJ Boston, C Brandau, W Catford, R Catherall, J Cederkäll, D Cullen, T Davinson, I Dillmann, C Dimopoulou, G Dracoulis, CE Düllmann, P Egelhof, A Estrade, D Fischer, K Flanagan, L Fraile, MA Fraser, SJ Freeman, H Geissel, J Gerl, P Greenlees, RE Grisenti, D Habs, R von Hahn, S Hagmann, M Hausmann, JJ He, M Heil, M Huyse, D Jenkins, A Jokinen, B Jonson, DT Joss, Y Kadi, N Kalantar-Nayestanaki, BP Kay, O Kiselev, H-J Kluge, M Kowalska, C Kozhuharov, S Kreim, T Kröll, J Kurcewicz, M Labiche, RC Lemmon, M Lestinsky, G Lotay, XW Ma, M Marta, J Meng, D Mücher, I Mukha, A Müller, AS Murphy, G Neyens, T Nilsson, C Nociforo, W Nörtershäuser, RD Page, M Pasini, N Petridis, N Pietralla, M Pfützner, Z Podolyák, P Regan, MW Reed, R Reifarth, P Reiter, R Repnow, K Riisager, B Rubio, MS Sanjari, DW Savin, C Scheidenberger, S Schippers, D Schneider, R Schuch, D Schwalm, L Schweikhard, D Shubina, E Siesling, H Simon, J Simpson, J Smith, K Sonnabend, M Steck, T Stora, T Stöhlker, B Sun, A Surzhykov, F Suzaki, O Tarasov, S Trotsenko, XL Tu, P Van Duppen, C Volpe, D Voulot, PM Walker, E Wildner, N Winckler, DFA Winters, A Wolf, HS Xu, A Yakushev, T Yamaguchi, YJ Yuan, YH Zhang, K Zuber (2012)Storage ring at HIE-ISOLDE: Technical design report: Technical design report, In: European Physical Journal: Special Topics207(1)pp. 1-117 EDP Sciences/Springer

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.

M Zielinska, A Goergen, E Clement, J-P Delaroche, M Girod, W Korten, A Buerger, W Catford, C Dossat, J Iwanicki, J Libert, J Ljungvall, PJ Napiorkowski, A Obertelli, D Pietak, R Rodriguez-Guzman, G Sletten, J Srebrny, C Theisen, K Wrzosek (2009)Shape of Ar-44: Onset of deformation in neutron-rich nuclei near Ca-48, In: PHYSICAL REVIEW C80(1)ARTN 0pp. ?-? AMER PHYSICAL SOC
C Longour, JG Narro, B Blank, M Lewitowicz, C Miehe, PH Regan, D Applebe, L Axelsson, AM Bruce, WN Catford, C Chandler, RM Clark, DM Cullen, S Czajkowski, JM Daugas, P Dessagne, A Fleury, L Frankland, W Gelletly, J Giovinazzo, B Greenhalgh, R Grzywacz, M Harder, KL Jones, N Kelsall, T Kszczot, RD Page, CJ Pearson, AT Reed, O Sorlin, R Wadsworth (1999)Half-lives of the odd-odd N=Z nuclei Y-78, Nb-82, Tc-86, In: JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS25(4)pp. 759-762
P Papka, TAD Brown, BR Fulton, DL Watson, SP Fox, D Groombridge, M Freer, NM Clarke, NI Ashwood, N Curtis, V Ziman, P McEwan, S Ahmed, WN Catford, D Mahboub, CN Timis, TD Baldwin, DC Weisser (2007)Decay path measurements for the 2.429 MeV state in Be-9: Implications for the astrophysical alpha+alpha+n reaction, In: PHYSICAL REVIEW C75(4)ARTN 0pp. ?-? AMER PHYSICAL SOC
NC Summers, SD Pain, NA Orr, WN Catford, JC Angelique, NI Ashwood, V Bouchat, NM Clarke, N Curtis, M Freer, BR Fulton, F Hanappe, M Labiche, JL Lecouey, RC Lemmon, D Mahboub, A Ninane, G Normand, FM Nunes, N Soic, L Stuttge, CN Timis, IJ Thompson, JS Winfield, V Ziman (2007)B(E1) strengths from Coulomb excitation of Be-11, In: PHYSICS LETTERS B650(2-3)pp. 124-128 ELSEVIER SCIENCE BV
N Curtis, NL Achouri, NI Ashwood, HG Bohlen, WN Catford, NM Clarke, M Freer, PJ Haigh, B Laurent, NA Orr, NP Patterson, N Soić, JS Thomas, V Ziman (2008)Structure of the brunnian nucleus 10C, In: Journal of Physics: Conference Series111(1)
R Orlandi, SD Pain, S Ahn, A Jungclaus, KT Schmitt, DW Bardayan, Wilton Catford, R Chapman, KA Chipps, JA Cizewski, CG Gross, ME Howard, KL Jones, RL Kozub, B Manning, M Matos, K Nishio, PD O’ Malley, WA Peters, ST Pittman, A Ratkiewicz, Callum Shand, JF Smith, MS Smith, T Fukui, Jeffrey Tostevin, Y Utsuno (2018)Neutron-hole states in 131Sn and spin-orbit splitting in neutron-rich nuclei, In: Physics Letters B785pp. 615-620 Elsevier

In atomic nuclei, the spin-orbit interaction originates from the coupling of the orbital motion of a nucleon with its intrinsic spin. Recent experimental and theoretical works have suggested a weakening of the spin-orbit interaction in neutron-rich nuclei far from stability. To study this phenomenon, we have investigated the spin-orbit energy splittings of single-hole and single-particle valence neutron orbits of 132Sn. The spectroscopic strength of single-hole states in 131Sn was determined from the measured differential cross sections of the tritons from the neutron-removing 132Sn(d,t)131Sn reaction, which was studied in inverse kinematics at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory. The spectroscopic factors of the lowest 3=2+, 1=2+ and 5=2+states were found to be (2 j+1), confirming the robust N = 82 shell closure at 132Sn. We compared the spin-orbit splitting of neutron single-hole states in 131Sn to those of single-particle states in 133Sn determined in a recent measurement of the 132Sn(d,p)133Sn reaction. We found a significant reduction of the energy splitting of the weakly bound 3p orbits compared to the well-bound 2d orbits, and that all the observed energy splittings can be reproduced remarkably well by calculations using a onebody spin-orbit interaction and a Woods-Saxon potential of standard radius and diffuseness. The observed reduction of spin-orbit splitting can be explained by the extended radial wavefunctions of the weakly bound orbits, without invoking a weakening of the spin-orbit strength.

M Freer, JD Malcolm, NL Achouri, NI Ashwood, DW Bardayan, SM Brown, WN Catford, KA Chipps, J Cizewski, N Curtis, KL Jones, T Munoz-Britton, SD Pain, N Soic, C Wheldon, GL Wilson, VA Ziman (2014)Resonances in C-14 observed in the He-4(Be-10,alpha)Be-10 reaction, In: PHYSICAL REVIEW C90(5)ARTN 05432 AMER PHYSICAL SOC
A Banu, L Trache, RE Tribble, F Carstoiu, F Negoita, F Rotaru, N Orr, L Achouri, B Laurent, B Roeder, M Chartier, B Fernandez-Dominguez, S Paschalis, B Pietras, P Roussel-Chomaz, L Gaudefroy, R Lemmon, M Labiche, W Catford, N Patterson, J Thomas, M Freer, M Horoi, A Bonaccorso (2008)Breakup of proton-rich nuclei 24Si, 23Al, 22Mg, 21Na at intermediate energies for reaction rates in explosive H-burning in novae, In: Proceedings of Science

We discuss the use of one proton-removal reactions of loosely bound nuclei at intermediate energies as an indirect method in nuclear astrophysics, with particular reference to the results of a GANIL experiment with a cocktail beam around 23Al at 50 MeV/nucleon. Momentum distributions of the core fragments, inclusive and in coincidence with gamma rays detected with EXOGAM, were measured. From them we determine mixing ratios in the structure of the ground states of the projectile nuclei and the asymptotic normalization of their wave functions. The method has the advantage that can be used for beams of low quality, such as cocktail beams, and intensities as low as a few pps. The proton breakup reactions provide information to determine astrophysical (p,γ) reaction rates that are outside the reach of other direct or indirect methods, or complementary information to the use of transfer reactions (the ANC method) which require radioactive beams of much better purity and intensity. Preliminary results on proton breakup of 24Si, 23Al, 22Mg and 21Na will be presented. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial- ShareAlikeLicence.

S Pietri, PH Regan, Z Podolyak, D Rudolph, S Steer, AB Garnsworthy, E Werner-Malento, R Hoischen, M Gorska, J Gerl, HJ Wollersheim, I Kojouharov, H Schaffner, F Becker, P Bednarczyk, L Caceres, P Doornenbal, H Geissel, J Grebosz, A Kelic, N Kurz, F Montes, W Prokopowicz, T Saito, S Tashenov, A Heinz, M Pfuetzner, T Kurtukian-Nieto, G Benzoni, M Hellstrom, A Jungclaus, J Simpson, L-L Andersson, L Atanasova, D Balabanski, MA Bentley, B Blank, A Blazhev, C Brandau, JR Brown, AM Bruce, F Camera, WN Catford, IJ Cullen, Z Dombradi, E Estevez, C Fahlander, W Gelletly, G Ilie, EK Johansson, J Jolie, GA Jones, M Kmiecik, FG Kondev, S Lalkovski, Z Liu, A Maj, S Myalski, T Shizuma, AJ Simons, S Schwertel, PM Walker, O Wieland (2007)Recent results in fragmentation isomer spectroscopy with rising, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS261(1-2)pp. 1079-1083
WN Catford, S Mohammadi, PH Regan, CS Purry, W Gelletly, PM Walker, GJ Gyapong, J Simpson, DD Warner, T Davinson, R Neal, RD Page, AC Shotter, IM Hibbert, R Wadsworth, SA Forbes, AM Bruce, C Thwaites, P Thirolf, P VanDuppen, W Galster, A Ninane, J Vervier, P Decrock, M Huyse, J Szerypo, J Wauters (1997)High resolution gamma-ray spectroscopy with a radioactive beam, In: NUCLEAR PHYSICS A616(1-2)pp. C303-C310
Ryan Wilkinson, Gavin Lotay, A. Lennarz, C. Ruiz, G. Christian, C. Akers, W. N. Catford, A. A. Chen, D. Connolly, B. Davids, D. A. Hutcheon, D. Jedrejcic, A. M. Laird, L. Martin, E. McNeice, J. Riley, M. Williams (2017)Direct Measurement of the Key Ec.m.=456 keV Resonance in the Astrophysical Ne19(p,γ)Na20 Reaction and Its Relevance for Explosive Binary Systems, In: Physical Review Letters119(24) American Physical Society

We have performed a direct measurement of the 19Ne(p,γ)20Na reaction in inverse kinematics using a beam of radioactive 19Ne. The key astrophysical resonance in the 19Ne+p system has been definitely measured for the first time at Ec.m.=456+5−2  keV with an associated strength of 17+7−5  meV. The present results are in agreement with resonance strength upper limits set by previous direct measurements, as well as resonance energies inferred from precision (3He, t) charge exchange reactions. However, both the energy and strength of the 456 keV resonance disagree with a recent indirect study of the 19Ne(d, n)20Na reaction. In particular, the new 19Ne(p,γ)20Na reaction rate is found to be factors of ∼8 and ∼5 lower than the most recent evaluation over the temperature range of oxygen-neon novae and astrophysical x-ray bursts, respectively. Nevertheless, we find that the 19Ne(p,γ)20Na reaction is likely to proceed fast enough to significantly reduce the flux of 19F in nova ejecta and does not create a bottleneck in the breakout from the hot CNO cycles into the rp process.

WN Catford, S Mohammadi, PH Regan, CS Purry, W Gelletly, PM Walker, GJ Gyapong, J Simpson, DD Warner, T Davinson, R Neal, RD Page, AC Shotter, IM Hibbert, R Wadsworth, SA Forbes, AM Bruce, C Thwaites, P Thirolf, P VanDuppen, W Galster, A Ninane, J Vervier, P Decrock, M Huyse, J Szerypo, J Wauters (1996)High resolution gamma-ray spectroscopy with a radioactive beam, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT371(3)pp. 449-459 ELSEVIER SCIENCE BV
N. Curtis, N. I. Ashwood, L. T. Baby, T. D. Baldwin, T. R. Bloxham, W. N. Catford, D. D. Caussyn, M. Freer, C. W. Harlin, P. McEwan, D. L. Price, D. Spingler, I. Wiedenhover (2006)alpha-decaying states in Be10,12 populated in the Be10(C14,Be10,12) reaction., In: Physical Review C73(057301)

A search has been made for the 6He+6He and alpha + 8He decay of the molecular rotational band in 12Be using the 10Be(14C,12Be*)12C reaction at 88.5 MeV. Although the alpha + 6He decay of 10Be was observed in the data set there is no evidence for the breakup of 12Be. The cross-section upper limits for the 10Be(14C,6He 6He)12C and 10Be(14C,alpha 8He)12C reactions are 50 and 300 nb respectively.

S Calinescu, L Caceres, S Grevy, O Sorlin, D Sohler, M Stanoiu, F Negoita, E Clement, R Astabatyan, C Borcea, R Borcea, M Bowry, W Catford, Z Dombradi, S Franchoo, R Garcia, R Gillibert, H Guerin, JC Thomas, I Kuti, S Lukyanov, A Lepailleur, V Maslov, P Morfouace, J Mrazek, M Niikura, L Perrot, Z Podolyak, C Petrone, Y Penionzhkevich, T Roger, F Rotaru, I Stefan, Z Vajta, E Wilson (2014)STUDY OF THE NEUTRON-RICH ISOTOPE Ar-46 THROUGH INTERMEDIATE ENERGY COULOMB EXCITATION, In: ACTA PHYSICA POLONICA B45(2)pp. 199-204
S. Ota, G. Christian, G. Lotay, W.N Catford, E.A Bennett, S. Dede, Daniel Doherty, Sam Hallam, J. Hooker, C. Hunt, H. Jayatissa, A. Matta, Mohamad Moukaddam, G.V Rogachev, A. Saastamoinen, Jeffrey Tostevin, S. Upadhyayula, Ryan Wilkinson (2020)Decay properties of 22Ne + resonances and their impact on s-process nucleosynthesis, In: Physics Letters B802135256 Elsevier

The astrophysical s-process is one of the two main processes forming elements heavier than iron. A key outstanding uncertainty surrounding s-process nucleosynthesis is the neutron flux generated by the 22Ne(; n)25Mg reaction during the He-core and C-shell burning phases of massive stars. This reaction, as well as the competing 22Ne(;)26Mg reaction, is not well constrained in the important temperature regime from 0:2–0:4 GK, owing to uncertainties in the nuclear properties of resonances lying within the Gamow window. To address these uncertainties, we have performed a new measurement of the 22Ne(6Li; d)26Mg reaction in inverse kinematics, detecting the outgoing deuterons and 25;26Mg recoils in coincidence. We have established a new n= decay branching ratio of 1:14(26) for the key Ex = 11:32 MeV resonance in 26Mg, which results in a new (; n) strength for this resonance of 42(11) eV when combined with the well-established (; ) strength of this resonance. We have also determined new upper limits on the partial widths of neutron-unbound resonances at Ex = 11:112; 11:163, 11:169, and 11:171 MeV. Monte-Carlo calculations of the stellar 22Ne(; n)25Mg and 22Ne(; )26Mg rates, which incorporate these results, indicate that both rates are substantially lower than previously thought in the temperature range from 0:2–0:4 GK.

A Ramus, NL Achouri, H Al Falou, NI Ashwood, D Beaumel, Y Blumenfeld, SM Brown, WN Catford, R Chapman, M Chartier, N Curtis, F Delaunay, B Fernandez-Dominguez, C Force, G De France, S Franchoo, J Guillot, D Gupta, P Haigh, F Hammache, M Labiche, V Lapoux, RC Lemmon, F Marechal, B Martin, X Mougeot, B Mouginot, L Nalpas, A Navin, NA Orr, N Patterson, B Pietras, EC Pollacco, A Le Prince, M Rejmund, JA Scarpaci, N De Sereville, I Stefan, O Sorlin, JS Thomas, GL Wilson (2009)STUDY OF THE O-20(d,t) REACTION WITH THE TIARA-MUST2-VAMOS-EXOGAM SETUP, In: INTERNATIONAL JOURNAL OF MODERN PHYSICS E-NUCLEAR PHYSICS18(10)pp. 2056-2060
AB Garnsworthy, PH Regan, S Pietri, Y Sun, FR Xu, D Rudolph, M Gorska, L Caceres, Z Podolyak, SJ Steer, R Hoischen, A Heinz, F Becker, P Bednarczyk, P Doornenbal, H Geissel, J Gerl, H Grawe, J Grebosz, A Kelic, I Kojouharov, N Kurz, F Montes, W Prokopwicz, T Saito, H Schaffner, S Tachenov, E Werner-Malento, HJ Wollersheim, G Benzoni, B Blank, C Brandau, AM Bruce, F Camera, WN Catford, IJ Cullen, Z Dombradi, E Estevez, W Gelletly, G Ilie, J Jolie, GA Jones, A Jungclaus, M Kmiecik, FG Kondev, T Kurtukian-Nieto, S Lalkovski, Z Liu, A Maj, S Myalski, M Pfuetzner, S Schwertel, T Shizuma, AJ Simons, PM Walker, O Wieland (2009)Isomeric states in neutron-deficient A similar to 80-90 nuclei populated in the fragmentation of Ag-107, In: PHYSICAL REVIEW C80(6)ARTN 0pp. ?-? AMER PHYSICAL SOC
JG Narro, C Longour, PH Regan, B Blank, CJ Pearson, M Lewitowicz, C Miehe, W Gelletly, D Appelbe, L Axelsson, AM Bruce, WN Catford, C Chandler, RM Clark, DM Cullen, S Czajkowski, JM Daugas, P Dessagne, A Fleury, L Frankland, J Giovinazzo, B Greenhalg, R Grzywacz, M Harder, KL Jones, N Kelsall, T Kszczot, RD Page, AT Reed, O Sorlin, R Wadsworth (2001)Fermi superallowed beta(+) decays and T=1 ground states of heavy odd-odd N=Z nuclei, In: PHYSICAL REVIEW C63(4)ARTN 04430 AMERICAN PHYSICAL SOC
S Pietri, PH Regan, Z Podolyak, D Rudolph, M Gorska, A Jungclaus, M Pfuetzner, AB Garnsworthy, SJ Steer, L Caceres, E Werner-Malento, R Hoischen, J Gerl, I Kojouharov, H Schaffner, HJ Wollersheim, F Becker, P Bednarczyk, P Doornenbal, H Geissel, J Grebosz, A Kelic, N Kurz, F Montes, W Prokopowicz, T Saito, S Tashenov, A Heinz, T Kurtukian-Nieto, G Benzoni, M Hellstrom, L-L Andersson, L Atanasova, DL Balabanski, MA Bentley, B Blank, A Blazhev, C Brandau, JR Brown, AM Bruce, F Camera, WN Catford, IJ Cullen, Z Dombradi, E Estevez, C Fahlander, W Gelletly, G Ilie, EK Johansson, J Jolie, GA Jones, M Kmiecik, FG Kondev, S Lalkovski, Z Liu, A Maj, S Myalski, T Shizuma, AJ Simons, S Schwertel, PM Walker, O Wieland (2007)First results from the stopped beam isomer rising campaign at GSI, In: ACTA PHYSICA POLONICA B38(4)pp. 1255-1264
M Freer, NI Ashwood, N Curtis, T Munoz-Britton, C Wheldon, VA Ziman, S Brown, WN Catford, NP Patterson, JS Thomas, DC Weisser (2008)Excited states of 8Be populated via the p(7Li, 4He)4He and p(7Li, 4He*) 4He resonant reactions, In: Journal of Physics G: Nuclear and Particle Physics35(12)
WN Catford, CN Timis, RC Lemmon, M Labiche, NA Orr, L Caballero, R Chapman, M Chartier, M Rejmund, H Savajols (2006)Neutron transfer studied with a radioactive beam of Ne-24, using TIARA at spiral, In: S Stoica, L Trache, RE Tribble (eds.), Exotic Nuclei and Nuclear/Particle Astrophysicspp. 12-19

In this thesis, the radioactive beam (RIB) 25Na at 5 MeV/u with an intensity of up to 3 times 107 pps is exploited to study states in 26Na using a 0.5 mg/cm2 deuterated polyethylene (CD2) target via the highly selective (d,p gamma) transfer reaction. The reaction products are recorded by using both SHARC (the Silicon Highly-segmented Array for Reactions and Coulex) and TIGRESS (The TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer). The SHARC array is installed at the ISAC-2 facility in TRIUMF (Canada) to study a variety of reactions, but single-particle transfer with a radioactive ion beam is the reaction mechanism of interest here. This experimental study was the first radioactive beam experiment making use of the TIGRESS/SHARC detector set-up in 2009. This work significantly extends an earlier analysis. The motivation of this work is to combine the information extracted from the particle and the gamma detection in 25Na(d,p gamma) 26Na reaction data to compare the experimentally observed results and the shell model predictions. A total of 24 states were studied, of which 10 had not been reported previously, and detailed new information was extracted for most of these. Properties measured and discussed include: (1) the observed gamma-ray decay branching ratios, (2) the observed spectroscopic factors (population strength) in the (d,p) reaction, (3) the observed angular momentum transfer in the (d,p) reaction, (4) a comparison between experimental and the predicted excitation energies from shell model calculations, (5) spin assignments based on the predicted reaction strengths and observed gamma-ray decay scheme, and (6) analogies with the experimentally observed gamma-decay properties of the isotone 28Al. An extra new feature of this work, for the important interpretation of similar future experiments, is a detailed study of the gamma-ray angular distributions and their dependence upon the scattered proton angles in (d,p).

M Zielinska, A Goergen, A Buerger, W Catford, E Clement, C Dossat, J Iwanicki, W Korten, J Liungvall, PJ Napiorkowski, D Pietak, G Sletten, J Srebrny, CH Theisen, K Wrzosek (2008)Coulomb excitation of neutron-rich Ar-44 at spiral, In: ACTA PHYSICA POLONICA B39(2)pp. 519-524
TAD Brown, P Papka, BR Fulton, DL Watson, SP Fox, D Groombridge, M Freer, NM Clarke, NI Ashwood, N Curtis, V Ziman, P McEwan, S Ahmed, WN Catford, D Mahboub, CN Timis, TD Baldwin, DC Weisser (2007)Decay studies for states in (9)Be up to 11 MeV: Insights into the n+(8)Be and alpha+(5)He cluster structure, In: PHYSICAL REVIEW C76(5)ARTN 0pp. ?-? AMER PHYSICAL SOC
GF Farrelly, Z Podolyak, SJ Steer, S Pietri, FR Xu, E Werner-Malento, T Shizuma, PH Regan, D Rudolph, AB Garnsworthy, R Hoischen, M Gorska, J Gerl, HJ Wollersheim, T Kurtukian-Nieto, G Benzoni, F Becker, P Bednarczyk, L Caceres, P Doornenbal, H Geisserl, J Grebosz, A Kelic, I Kojouharov, N Kurz, F Montes, W Prokopowicz, T Saito, H Schaffner, S Tashenov, A Heinz, M Pfuezner, A Jungclaus, DL Balabanski, C Brandau, AM Bruce, WN Catford, IJ Cullen, Z Dombradi, E Estevez, W Gelletly, G Ilie, J Jolie, GA Jones, M Kmiecik, FG Kondev, R Kruecken, S Lalkovski, HL Liu, Z Liu, A Maj, S Myalski, S Schwerrel, PM Walker, O Wieland (2009)REVISION OF THE K-ISOMER IN W-190(116), In: ACTA PHYSICA POLONICA B40(3)pp. 885-888
X Pereira-López, B Fernández-Domínguez, F Delaunay, N. L Achouri, N. A Orr, W. N Catford, M Assié, S Bailey, B Bastin, Y Blumenfeld, R Borcea, M Caamaño, L Caceres, E Clément, A Corsi, N Curtis, Q Deshayes, F Farget, M Fisichella, G de France, S Franchoo, M Freer, J Gibelin, A Gillibert, G. F Grinyer, F Hammache, O Kamalou, A Knapton, T Kokalova, V Lapoux, J. A Lay, B Le Crom, S Leblond, J Lois-Fuentes, F. M Marqués, A Matta, P Morfouace, A. M Moro, T Otsuka, J Pancin, L Perrot, J Piot, E Pollacco, D Ramos, C Rodríguez-Tajes, T Roger, F Rotaru, M Sénoville, N de Séréville, R Smith, O Sorlin, M Stanoiu, I Stefan, C Stodel, D Suzuki, T Suzuki, J. C Thomas, N Timofeyuk, M Vandebrouck, J Walshe, C Wheldon (2020)Low-lying single-particle structure of 17C and the N = 14 sub-shell closure, In: Physics Letters. B811135939 Elsevier

The first investigation of the single-particle structure of the bound states of 17C, via the C transfer reaction, has been undertaken. The measured angular distributions confirm the spin-parity assignments of and for the excited states located at 217 and 335 keV, respectively. The spectroscopic factors deduced for these states exhibit a marked single-particle character, in agreement with shell model and particle-core model calculations, and combined with their near degeneracy in energy provide clear evidence for the absence of the sub-shell closure. The very small spectroscopic factor found for the ground state is consistent with theoretical predictions and indicates that the strength is carried by unbound states. With a dominant valence neutron configuration and a very low separation energy, the excited state is a one-neutron halo candidate.

KJ Jones, SD Pain, RL Kozub, AS Adekola, DW Bardayan, JC Blackmon, WN Catford, KY Chae, K Chipps, JA Cizewskit, L Erikson, AL Gaddis, U Greife, R Grzywacz, C Harlin, R Hatarik, JA Howard, J James, R Kapler, JF WKrólas, Z Liang, C Ma, BH Matei, CD Moazen, PD Nesaraja, NP O'Malley, SV Patterson, D Paulauskas, JF Shapira, M Shriner Jr, DJ Sikora, MS Sissom, TP Smith, JS Swan, GL Thomas, Wilson (2009)Studies of nuclei close to132 Sn using single-neutron transfer reactions, In: AIP Conference Proceedings1098pp. 153-160
N Curtis, NL Achouri, NI Ashwood, HG Bohlen, WN Catford, NM Clarke, M Freer, PJ Haigh, B Laurent, NA Orr, NP Patterson, N Soic, JS Thomas, V Ziman (2008)Breakup reaction study of the Brunnian nucleus (10)C, In: PHYSICAL REVIEW C77(2)ARTN 0pp. ?-? AMER PHYSICAL SOC
LS Caceres, M Gorska, A Jungclaus, PH Regan, AB Garnsworthy, S Pietri, Z Podolyak, D Rudolph, SJ Steer, H Grawe, DL Balabanski, F Becker, P Bednarczyk, G Benzoni, B Blank, C Brandau, AM Bruce, F Camera, WN Catford, IJ Cullen, Z Dombradi, P Doornenbalal, E Estevez, H Geissel, W Gelletly, J Gerl, J Grebosz, A Heinz, R Hoischen, G Ilie, J Jolie, GA Jones, M Kmiecik, I Kojouharov, FG Kondev, T Kurtukian-Nieto, N Kurz, S Lalkowski, L Liu, A Maj, S Myalsk, F Montes, M Pfuetzner, W Prokopowicz, T Saito, H Schatfner, S Schwertel, T Shizuma, AJ Simons, S Tashenov, PM Walker, E Werner-Malento, O Wielandh, HJ Wollersheim (2007)Identification of excited states in the N = Z nucleus Nb-82, In: ACTA PHYSICA POLONICA B38(4)pp. 1271-1275
S Hallam, G Lotay, A Gade, D T Doherty, J Belarge, P C Bender, B A Brown, J Browne, W N Catford, B Elman, A Estradé, M R Hall, B Longfellow, E Lunderberg, F Montes, M Moukaddam, P O'Malley, W-J Ong, H Schatz, D Seweryniak, K Schmidt, N K Timofeyuk, D Weisshaar, R G T Zegers (2021)Exploiting Isospin Symmetry to Study the Role of Isomers in Stellar Environments, In: Physical review letters126(4)042701 American Physical Society

Proton capture on the excited isomeric state of ^{26}Al strongly influences the abundance of ^{26}Mg ejected in explosive astronomical events and, as such, plays a critical role in determining the initial content of radiogenic ^{26}Al in presolar grains. This reaction also affects the temperature range for thermal equilibrium between the ground and isomeric levels. We present a novel technique, which exploits the isospin symmetry of the nuclear force, to address the long-standing challenge of determining proton-capture rates on excited nuclear levels. Such a technique has in-built tests that strongly support its veracity and, for the first time, we have experimentally constrained the strengths of resonances that dominate the astrophysical ^{26m}Al(p,γ)^{27}Si reaction. These constraints demonstrate that the rate is at least a factor ∼8 lower than previously expected, indicating an increase in the stellar production of ^{26}Mg and a possible need to reinvestigate sensitivity studies involving the thermal equilibration of ^{26}Al.

GL Wilson, WN Catford, NA Orr, C Diget, A Matta, G Hackman, SJ Williams, IC Celik, NL Achouri, H Al Falou, R Ashley, RAE Austin, GC Ball, JC Blackmon, AJ Boston, HC Boston, SM Brown, DS Cross, M Djongolov, TE Drake, U Hager, SP Fox, BR Fulton, N Galinski, AB Garnsworthy, D Jamieson, R Kanungo, KG Leach, JN Orce, CJ Pearson, M Porter-Peden, F Sarazin, EC Simpson, S Sjue, D Smalley, C Sumithrarachchi, C Unsworth, S Triambak, R Wadsworth (2016)Shell evolution approaching the N = 20 island of inversion: Structure of 26Na, In: Physics Letters B Elsevier

The levels in 26Na with single particle character have been observed for the first time using the d(25Na, pγ ) reaction at 5 MeV/nucleon. The measured excitation energies and the deduced spectroscopic factors are in good overall agreement with (0+1)ħω(0+1)ħω shell model calculations performed in a complete spsdfpspsdfp basis and incorporating a reduction in the N=20 gapN=20 gap. Notably, the 1p3/21p3/2 neutron configuration was found to play an enhanced role in the structure of the low-lying negative parity states in 26Na, compared to the isotone 28Al. Thus, the lowering of the 1p3/21p3/2 orbital relative to the 0f7/20f7/2 occurring in the neighbouring Z=10Z=10 and 12 nuclei – 25,27Ne and 27,29Mg – is seen also to occur at Z=11Z=11 and further strengthens the constraints on the modelling of the transition into the island of inversion.

M Freer, NI Ashwood, N Curtis, J Malcolm, T Munoz-Britton, C Wheldon, VA Ziman, J Carter, H Fujita, I Usman, Z Buthelezi, SV Fortsch, R Neveling, SM Perez, FD Smit, RW Fearick, P Papka, JA Swartz, S Brown, WN Catford, G Wilson, D Bardayan, SD Pain, K Chipps, K Grzywacz-Jones, N Soic, NL Achouri (2010)CLUSTER STATES IN C-12 AND C-14, In: MODERN PHYSICS LETTERS A25(21-23)pp. 1833-1837 WORLD SCIENTIFIC PUBL CO PTE LTD

The cluster structure of C-12 is explored and recent measurements of proton inelastic scattering, suggesting a 2(+) state close to 9.6 MeV are presented. Resonant scattering studies of Be-10+He-4 used to populate resonances in C-14 are briefly discussed.

B Fernandez-Dominguez, X Pereira-Lopez, NK Timofeyuk, P Descouvemont, WN Catford, F Delaunay (2015)Spectroscopic study of the exotic nucleus P-25, In: PHYSICAL REVIEW C91(2)ARTN 0 American Physical Society

Motivated by the importance of P25 for the two-proton decay of S26 and for searches of the mirror analog of the island of inversion near N=16, we present the first predictions for the spectroscopy of the exotic isotope P25 obtained in the shell model, a potential model, and a microscopic-cluster model. All models predict P25 to be unbound, with an energy in the range 0.78-1.03 MeV, which favors previous mass systematics over more recent revisions. We show that P25 possesses a rich low-lying spectrum that should be accessible by experimental studies. All of the predicted states below 7 MeV, except one, are narrow. Many of them are built on the excited-core states of 24Si for which the Coulomb barrier is raised. For decays into the 24Si(g.s.)+p channel we determined the proton widths based on their link to the asymptotic normalization coefficients (ANCs) of their mirror analogs in 25Ne. We determine these ANCs from the analysis of the transfer reaction 24Ne(d,p)25Ne. The proton widths for decay into excited-state channels are obtained in model calculations. The only broad state is the intruder 3/2-, the mirror analog of which has been recently observed in 25Ne. The 25P(3/2-) energy is lower than that in 25Ne, suggesting that the island of inversion may persist on the proton-rich side. All excited states of P25 have at least two decay modes and are expected to populate variously the 21,2+ and 4+ states in 24Si, which then decay electromagnetically.

S Myalski, A Maj, Z Podolyak, F Becker, P Bednarczyk, G Benzoni, B Blank, C Brandau, AM Bruce, L Caceres, F Camera, WN Catford, IJ Cullen, Z Dombradi, P Doornenbal, E Estevez, AB Garnsworthy, H Geissel, W Gelletly, J Gerl, M Corska, H Grawe, J Grebosz, A Heinz, R Hoischen, G Ilie, GA Jones, A Jungclaus, A Kelic, M Kmiecik, I Kojouharov, FG Kondev, T Kurtukian-Nieto, N Kurz, S Lalkovski, Z Liu, F Montes, M Pfuetzner, S Pietri, W Prokopowicz, PH Regan, D Rudolph, T Saito, H Schaffner, S Schwertel, T Shizuma, AJ Simon, SJ Steer, S Tashenov, PM Walker, E Werner-Malento, O Wieland, HJ Wollersheim (2009)ISOMERIC RATIOS FOR NUCLEI WITH Z=62-67 AND A=142-152 PRODUCED IN THE RELATIVISTIC FRAGMENTATION OF Pb-208, In: ACTA PHYSICA POLONICA B40(3)pp. 879-883
C Longour, JG Narro, B Blank, M Lewitowicz, C Miehe, PH Regan, D Applebe, L Axelsson, AM Bruce, WN Catford, C Chandler, RM Clark, DM Cullen, S Czajkowski, JM Daugas, P Dessagne, A Fleury, L Frankland, W Gelletly, J Giovinazzo, B Greenhalgh, R Grzywacz, M Harder, KL Jones, N Kelsall, T Kszczot, RD Page, CJ Pearson, AT Reed, O Sorlin, R Wadsworth (1998)Observation of Fermi superallowed beta(+) decays in heavy odd-odd, N = Z nuclei: Evidence for 0(+) ground states in Y-78, Nb-82, and Tc-86, In: PHYSICAL REVIEW LETTERS81(16)pp. 3337-3340 AMERICAN PHYSICAL SOC
S Calinescu, L Caceres, S Grevy, O Sorlin, Z Dombradi, M Stanoiu, R Astabatyan, C Borcea, R Borcea, M Bowry, Wilton Catford, E Clement, S Franchoo, R Garcia, R Gillibert, IH Guerin, I Kuti, S Lukyanov, A Lepailleur, V Maslov, P Morfouace, J Mrazek, F Negoita, M Niikura, L Perrot, Zsolt Podolyak, C Petrone, Y Penionzhkevich, T Roger, F Rotaru, D Sohler, I Stefan, JC Thomas, Z Vajta, E Wilson (2016)Coulomb excitation of Ca-44 and Ar-46, In: PHYSICAL REVIEW C93(4)ARTN 04433 AMER PHYSICAL SOC

The reduced transition probabilities B(E2; 0+ g.s. → 2+ 1 ) of the 46Ar and 44Ca nuclei were studied using the Coulomb excitation technique at intermediate energy at the LISE/GANIL facility. The in-flight γ rays, emitted after the Coulomb excitation of their first 2+ states, were detected in an array of 64 BaF2 crystals. The present B(E2 ↑) value for 44Ca, 475(36) e2fm4 , agrees well with the value of 495(35) e2fm4 obtained by averaging results of previous experiments. Consistent B(E2; 0+ g.s. → 2+ 1 ) values of 225(29) e2fm4 and 234(19) e2fm4 have been obtained for 46Ar from an absolute and a relative measurement, normalized to the 44Ca value. Both results agree with the ones obtained with the same experimental technique at the NSCL facility but are a factor of 2 smaller than the shell model predictions. The drop in B(E2; 0+ g.s. → 2+ 1 ) in the Ar chain at N = 28, confirmed in this experiment, shows that 46Ar is sensitive to the N = 28 shell closure.

C Beck, A SÀnchez I Zafra, P Papka, S Thummerer, F Azaiez, P Bednarczyk, S Courtin, D Curien, O Dorvaux, D Lebhertz, A Nourreddine, J Robin, M Rousseau, W Von Oertzen, B Gebauer, T Kokalova, C Wheldon, G De Angelis, A Gadea, S Lenzi, S Szilner, DR Napoli, WN Catford, DG Jenkins, G Royer (2008)Alpha-cluster states populated in 24Mg + 12C, In: International Journal of Modern Physics E17(10)pp. 2049-2054
A Khouaja, ACC Villari, M Benjelloun, D Hirata, G Auger, H Savajols, W Mittig, P Roussel-Chomaz, NA Orr, MG Saint-Laurent, S Pita, A Gillibert, M Chartier, CE Demonchy, L Giot, D Baiborodin, Y Penionzhkevich, WN Catford, A Lepine-Szily, Z Dlouhy (2006)Reaction cross-section and reduced strong absorption radius measurements of neutron-rich nuclei in the vicinity of closed shells N=20 and N=28, In: NUCLEAR PHYSICS A780(1-2)pp. 1-12 ELSEVIER SCIENCE BV
SD Pain, WN Catford, NA Orr, JC Angelique, NI Ashwood, V Bouchat, NM Clarke, N Curtis, M Freer, B Fulton, F Hanappe, M Labiche, JL Lecouey, R Lemmon, D Mahboub, A Ninane, G Normand, N Soic, L Stuttge, CN Timis, JA Tostevin, V Ziman, J Winfield, D Seweryniak, TL Khoo (2005)Evidence of a (1d(5/2))(2) component to the Be-12 ground state, In: Nuclei at the Limits764pp. 373-378

Data have been obtained on exclusive single neutron knockout cross sections from 12Be to study its ground state structure. The cross sections for the production of 11Be in its ground state (1/2 +) and first excited state (0.32 MeV, 1/2 -) have previously been measured, indicating a strong (2s 1 2) 2 component to the 12Be ground state. In the present experiment, performed at the GANIL laboratory, cross sections for the first (0.32 MeV, 1/2 -) and second (1.78 MeV, 5/2 +, unbound) excited states in 11Be were measured, which gives information on the admixture of (1p 1 2) 2 and (1d 5 2) 2 components in the ground state of 12Be. A fragmentation beam of 12Be of ∼10000 pps (95% pure) was incident on a carbon target at 41 MeV/u. The beam particles were tracked onto the target, and their energies were measured event-by-event. The beam-like residues were measured in a position sensitive telescope mounted at zero degrees, and neutrons were measured in the DéMoN array. The 1/2 - state of 11Be was identified by measuring coincident 320 keV γ-rays, using four NaI detectors. Full kinematic reconstruction of unbound states in 11Be was performed using coincident neutrons and 10Be ions. Detailed simulations were performed in order to interpret the data, and spectroscopic factors were calculated, using preliminary single particle removal cross sections calculated using a Glauber model. © 2005 American Institute of Physics.

JM Daugas, T Faul, H Grawe, M Pfuetzner, R Grzywacz, M Lewitowicz, NL Achouri, JC Angelique, D Baiborodin, R Bentida, R Beraud, C Borcea, CR Bingham, WN Catford, A Emsallem, G de France, KL Grzywacz, RC Lemmon, MJL Jimenez, FDO Santos, PH Regan, K Rykaczewski, JE Sauvestre, M Sawicka, M Stanoiu, K Sieja, F Nowacki (2010)Low-lying isomeric levels in Cu-75, In: PHYSICAL REVIEW C81(3)ARTN 0pp. ?-? AMER PHYSICAL SOC
A Gorgen, E Clement, W Korten, E Bouchez, A Chatillon, A Hurstel, Y Le Coz, C Theisen, JN Wilson, M Zielinska, C Andreoiu, F Becker, P Butler, JM Casandjian, WN Catford, T Czosnyka, G de France, J Gerl, R-D Herzberg, J Iwanicki, DG Jenkins, GD Jones, PJ Napiorkowski, G Sletten, C Timis (2007)Shape coexistence in Kr-74 and Kr-76, In: EUROPEAN PHYSICAL JOURNAL-SPECIAL TOPICS150pp. 117-120
J. N. Wilson, M. Lebois, L. Qi, P. Amador-Celdran, D. Bleuel, J. A. Briz, R. Carroll, Wilton Catford, H. De Witte, D. T. Doherty, R. Eloirdi, G. Georgiev, A. Gottardo, A. Goasduff, K. Hadyńska-Klęk, K. Hauschild, H. Hess, V. Ingeberg, T. Konstantinopoulos, J. Ljungvall, A. Lopez-Martens, G. Lorusso, R. Lozeva, R. Lutter, P. Marini, I. Matea, T. Materna, L. Mathieu, A. Oberstedt, S. Oberstedt, S. Panebianco, Zsolt Podolyak, A. Porta, Patrick Regan, P. Reiter, K. Rezynkina, S. J. Rose, E. Sahin, M. Seidlitz, O. Serot, Robert Shearman, B. Siebeck, S. Siem, A. G. Smith, G. M. Tveten, D. Verney, N. Warr, F. Zeiser, M. Zielinska (2017)Anomalies in the Charge Yields of Fission Fragments from the U(n,f)238 Reaction, In: Physical Review Letters118(22)pp. 222501-1 American Physical Society

Fast-neutron-induced fission of 238U at an energy just above the fission threshold is studied with a novel technique which involves the coupling of a high-efficiency γ-ray spectrometer (MINIBALL) to an inverse-kinematics neutron source (LICORNE) to extract charge yields of fission fragments via γ−γ coincidence spectroscopy. Experimental data and fission models are compared and found to be in reasonable agreement for many nuclei; however, significant discrepancies of up to 600% are observed, particularly for isotopes of Sn and Mo. This indicates that these models significantly overestimate the standard 1 fission mode and suggests that spherical shell effects in the nascent fission fragments are less important for low-energy fast-neutron-induced fission than for thermal neutron-induced fission. This has consequences for understanding and modeling the fission process, for experimental nuclear structure studies of the most neutron-rich nuclei, for future energy applications (e.g., Generation IV reactors which use fast-neutron spectra), and for the reactor antineutrino anomaly.

JA Cizewski, KL Jones, RL Kozub, SD Pain, A Adekola, DW Bardayan, JC Blackmon, WN Catford, KY Chae, KA Chipps, L Erikson, A Gaddis, R Grzywacz, C Harlin, R Hatarik, J Howard, MS Johnson, R Kapler, W Królas, JF Liang, R Livesay, Z Ma, C Matei, B Moazen, CD Nesaraja, P O'Malley, SV Paulauskas, WA Peters, D Shapira, JF Shriner Jr, DJ Sissom, MS Smith, TP Swan, JS Thomas, GL Wilson (2009)Neutron-transfer reaction studies with fission fragment radioactive ion beams near 132Sn, In: AIP Conference Proceedings1175pp. 147-153
T. L. Tang, B. P. Kay, C. R. Hoffman, J. P. Schiffer, D. K. Sharp, L. P. Gaffney, S. J. Freeman, M. R. Mumpower, A. Arokiaraj, E. F. Baader, P. A. Butler, W. N. Catford, G. de Angelis, F. Flavigny, M. D Gott, E. T. Gregor, J. Konki, M. Labiche, I. H. Lazurus, P. T. MacGregor, I. Martel, R. D. Page, Zs Podolyak, O. Poleshchuk, R. Raabe, F. Recchia, J. F. Smith, S. V. Szwec, J. Yang (2020)First Exploration of Neutron Shell Structure Below Lead and Beyond N = 126, In: Physical Review Letters American Physical Society

The nuclei below lead but with more than 126 neutrons are crucial to an understanding of the astrophysical r-process in producing nuclei heavier than A ~ 190. Despite their importance, the structure and properties of these nuclei remain experimentally untested as they are difficult to produce in nuclear reactions with stable beams. In a first exploration of the shell structure of this region, neutron excitations in 207Hg have been probed using the neutron-adding (d,p) reaction in inverse kinematics. The radioactive beam of 206Hg was delivered to the new ISOLDE Solenoidal Spectrometer at an energy above the Coulomb barrier. The spectroscopy of 207Hg marks a first step in improving our understanding of the relevant structural properties of nuclei involved in a key part of the path of the r-process.

D Smalley, F Sarazin, FM Nunes, BA Brown, P Adsley, H Al-Falou, C Andreoiu, B Baartman, GC Ball, JC Blackmon, HC Boston, WN Catford, S Chagnon-Lessard, A Chester, RM Churchman, DS Cross, CA Diget, D Di Valentino, SP Fox, BR Fulton, A Garnsworthy, G Hackman, U Hager, R Kshetri, JN Orce, NA Orr, E Paul, M Pearson, ET Rand, J Rees, S Sjue, CE Svensson, E Tardiff, AD Varela, SJ Williams, S Yates (2014)Two-neutron transfer reaction mechanisms in C-12(He-6,He-4)C-14 using a realistic three-body He-6 model, In: PHYSICAL REVIEW C89(2)ARTN 02460 AMER PHYSICAL SOC
AN Antonov, MK Gaidarov, MV Ivanov, DN Kadrev, M Aïche, G Barreau, S Czajkowski, B Jurado, G Belier, A Chatillon, T Granier, J Taieb, D Doré, A Letourneau, D Ridikas, E Dupont, E Berthoumieux, S Panebianco, F Farget, C Schmitt, L Audouin, E Khan, L Tassan-Got, T Aumann, P Beller, K Boretzky, A Dolinskii, P Egelhof, H Emling, B Franzke, H Geissel, A Kelic-Heil, O Kester, N Kurz, Y Litvinov, G Münzenberg, F Nolden, K-H Schmidt, C Scheidenberger, H Simon, M Steck, H Weick, J Enders, N Pietralla, A Richter, G Schrieder, A Zilges, MO Distler, H Merkel, U Müller, AR Junghans, H Lenske, M Fujiwara, T Suda, S Kato, T Adachi, S Hamieh, MN Harakeh, N Kalantar-Nayestanaki, H Wörtche, GPA Berg, IA Koop, PV Logatchov, AV Otboev, VV Parkhomchuk, DN Shatilov, PY Shatunov, YM Shatunov, SV Shiyankov, DI Shvartz, AN Skrinsky, LV Chulkov, BV Danilin, AA Korsheninnikov, EA Kuzmin, AA Ogloblin, VA Volkov, Y Grishkin, VP Lisin, AN Mushkarenkov, V Nedorezov, AL Polonski, NV Rudnev, AA Turinge, A Artukh, V Avdeichikov, SN Ershov, A Fomichev, M Golovkov, AV Gorshkov, L Grigorenko, S Klygin, S Krupko, IN Meshkov, A Rodin, Y Sereda, I Seleznev, S Sidorchuk, E Syresin, S Stepantsov, G Ter-Akopian, Y Teterev, AN Vorontsov, SP Kamerdzhiev, EV Litvinova, S Karataglidis, R Alvarez Rodriguez, MJG Borge, C Fernandez Ramirez, E Garrido, P Sarriguren, JR Vignote, LM Fraile Prieto, J Lopez Herraiz, E Moya De Guerra, J Udias-Moinelo, JE Amaro Soriano, AM Lallena Rojo, JA Caballero, HT Johansson, B Jonson, T Nilsson, G Nyman, M Zhukov, P Golubev, D Rudolph, K Hencken, J Jourdan, B Krusche, T Rauscher, D Kiselev, D Trautmann, J Al-Khalili, W Catford, R Johnson, PD Stevenson, C Barton, D Jenkins, R Lemmon, M Chartier, D Cullen, CA Bertulani, A Heinz (2011)The electronion scattering experiment ELISe at the International Facility for Antiproton and Ion Research (FAIR) - A conceptual design study, In: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment637(1)pp. 60-76
SJ Steer, Z Podolyak, S Pietri, M Gorska, PH Regan, D Rudolph, E Werner-Malento, AB Garnsworthy, R Hoischen, J Gerl, HJ Wollersheim, KH Maier, H Grawe, F Becker, P Bednarczyk, L Caceres, P Doornenbal, H Geissel, J Greabosz, A Kelic, I Kojouharov, N Kurz, F Montes, W Prokopowicz, T Saito, H Schaffner, S Tashenov, A Heinz, M Pfuetzner, T Kurtukian-Nieto, G Benzoni, A Jungclaus, DL Balabanski, C Brandau, BA Brown, AM Bruce, WN Catford, IJ Cullen, Z Dombradi, ME Estevez, W Gelletly, G Ilie, J Jolie, GA Jones, M Kmiecik, FG Kondev, R Kruecken, S Lalkovski, Z Liu, A Maj, S Myalski, S Schwertel, T Shizuma, PM Walker, O Wieland (2008)Single-particle behavior at N=126: Isomeric decays in neutron-rich Pt-204, In: PHYSICAL REVIEW C78(6)ARTN 0pp. ?-? AMER PHYSICAL SOC
L Atar, S Paschalis, Carlo Barbieri, C Bertulani, P Díaz Fernández, M Hollington, M Najafi, V Panin, H Alvarez-Pol, T Aumann, V Avdeichikov, S Beceiro-Novo, D Bemmerer, J Benlliure, J Boillos, K Boretzky, M Borge, M Caamaño, C Caesar, E Casarejos, Wilton Catford, J Cederkall, M Chartier, L Chulkov, D Cortina-Gil, E Cravo, R Crespo, I Dillmann, Z Elekes, J Enders, O Ershova, A Estrade, F Farinon, L Fraile, M Freer, D Galaviz Redondo, H Geissel, R Gernhäuser, P Golubev, K Göbel, J Hagdahl, T Heftrich, M Heil, M Heine, A Heinz, A Henriques, A Hufnagel, A Ignatov, H Johansson, B Jonson, J Kahlbow, N Kalantar-Nayestanaki, R Kanungo, A Kelic-Heil, A Knyazev, T Kröll, N Kurz, M Labiche, C Langer, T Le Bleis, R Lemmon, S Lindberg, J Machado, J Marganiec-Gałązka, A Movsesyan, E Nacher, E Nikolskii, T Nilsson, C Nociforo, A Perea, M Petri, S Pietri, R Plag, R Reifarth, G Ribeiro, C Rigollet, D Rossi, M Röder, D Savran, H Scheit, H Simon, O Sorlin, I Syndikus, J Taylor, O Tengblad, R Thies, Y Togano, M Vandebrouck, P Velho, V Volkov, A Wagner, F Wamers, H Weick, C Wheldon, G Wilson, J Winfield, P Woods, D Yakorev, M Zhukov, A Zilges, K Zuber (2018)Quasifree ( p , 2p ) Reactions on Oxygen Isotopes: Observation of Isospin Independence of the Reduced Single-Particle Strength, In: Physical Review Letters120(5)052501 American Physical Society

Quasifree one-proton knockout reactions have been employed in inverse kinematics for a systematic study of the structure of stable and exotic oxygen isotopes at the R3B=LAND setup with incident beam energies in the range of 300–450 MeV=u. The oxygen isotopic chain offers a large variation of separation energies that allows for a quantitative understanding of single-particle strength with changing isospin asymmetry. Quasifree knockout reactions provide a complementary approach to intermediate-energy onenucleon removal reactions. Inclusive cross sections for quasifree knockout reactions of the type AOðp; 2pÞA−1N have been determined and compared to calculations based on the eikonal reaction theory. The reduction factors for the single-particle strength with respect to the independent-particle model were obtained and compared to state-of-the-art ab initio predictions. The results do not show any significant dependence on proton-neutron asymmetry.

WN Catford, CN Timis, RC Lemmon, M Labiche, NA Orr, L Caballero, R Chapman, M Chartier, M Rejmund, H Savajols, TIARA Collaboration (2009)Neutron Transfer Studied with a Radioactive beam of 24Ne, using TIARA at SPIRAL

A general experimental technique for high resolution studies of nucleon transfer reactions using radioactive beams is briefly described, together with the first new physics results that have been obtained with the new TIARA array. These first results from TIARA are for the reaction 24Ne(d,p)25Ne, studied in inverse kinematics with a pure radioactive beam of 100,000 pps from the SPIRAL facility at GANIL. The reaction probes the energies of neutron orbitals relevant to very neutron rich nuclei in this mass region and the results highlight the emergence of the N=16 magic number for neutrons and the associated disappearance of the N=20 neutron magic number for the very neutron rich neon isotopes.

A Rahaman, U Datta Pramanik, T Aumann, S Beceiro, K Boretzky, C Caesar, BV Carlson, WN Catford, S Chakraborty, S Chatterjee, M Chartier, G De Angelis, D Cortina-Gil, D Gonzalez-Diaz, H Emling, P Diaz Fernandez, LM Fraile, O Ershova, H Geissel, M Heil, B Jonson, A Kelic, H Johansson, R Kruecken, T Kroll, J Kurcewicz, C Langer, T Le Bleis, Y Leifels, G Munzenberg, J Marganiec, C Nociforo, A Najafi, V Panin, S Paschalis, S Pietri, R Plag, R Reifarth, V Ricciardi, D Rossi, J Ray, H Simon, C Scheidenberge, S Typel, J Taylor, Y Togano, V Volkov, H Weick, A Wagner, F Wamers, M Weigand, JS Winfield, D Yakorev, M Zoric (2014)Study of ground state wave-function of the Neutron-rich 29,30Na isotopes through coulomb breakup, In: EPJ Web of Conferences66

Coulomb breakup of unstable neutron rich nuclei 29,30Na around the 'island of inversion' has been studied at energy around 434 MeV/nucleon and 409 MeV/nucleon respectively. Four momentum vectors of fragments, decay neutron from excited projectile and γ-rays emitted from excited fragments after Coulomb breakup are measured in coincidence. For these nuclei, the low-lying dipole strength above one neutron threshold can be explained by direct breakup model. The analysis for Coulomb breakup of 29,30Na shows that large amount of the cross section yields the 28Na, 29Na core in ground state. The predominant ground-state configuration of 29,30Na is found to be 28Na(g.s) νs1/2 and 29Na(g.s) νs1/2,respectively. © Owned by the authors, published by EDP Sciences, 2014.

A Banu, L Trache, F Carstoiu, NA Orr, NL Achouri, A Bonaccorso, WN Catford, M Chartier, B Fernandez-Dominguez, M Freer, L Gaudefroy, M Horoi, M Labiche, B Laurent, RC Lemmon, F Negoita, S Paschalis, N Patterson, B Pietras, B Roeder, F Rotaru, P Roussel-Chomaz, E Simmons, JS Thomas, RE Tribble (2010)Astrophysically important reaction rates for novae and X-ray bursts from proton breakup at intermediate energies, In: AIP Conference Proceedings1304pp. 339-343

We discuss the use of one-nucleon removal reactions of loosely bound nuclei at intermediate energies as an indirect method in nuclear astrophysics. The breakup reactions are proved to be good spectroscopic tools and can be used to study a large number of loosely bound proton- or neutron-rich nuclei over a wide range of beam energies. As peripheral processes, they can be used to extract asymptotic normalization coefficients (ANCs) from which non-resonant capture reaction rates of astrophysical interest can be calculated parameter free. In this talk, we present results of a proton-breakup experiment carried out at GANIL (France) with a cocktail beam centered around 23Al at 50 MeV/nucleon. Momentum distributions of the breakup fragments, inclusive and in coincidence with gamma rays detected by EXOGAM Germanium clover array, were measured in the focal plan of SPEG energy-loss spectrometer. We present in particular the investigations of reaction rates for 22Mg(p,γ)23Al and 23Al(p,γ)24Si important for novae and X-ray bursts, respectively.

Laila Gurgi, Patrick Regan, P-A Söderström, H Watanabe, Philip Walker, Zsolt Podolyak, S Nishimura, Thomas Berry, P Doornenbal, G Lorusso, T Isobe, H Baba, ZY Xu, H Sakurai, T Sumikama, Wilton Catford, AM Bruce, F Browne, GJ Lane, FG Kondev, A Odahara, J Wu, HL Liu, FR Xu, Z Korkulu, P Lee, JJ Liu, VH Phong, A Yagi, GX Zhang, T Alharbi, RJ Carroll, KY Chae, Z Dombradi, A Estrade, N Fukuda, C Griffin, E Ideguchi, N Inabe, H Kanaoka, I Kojouharov, T Kubo, S Kubono, N Kurz, I Kuti, S Lalkovski, EJ Lee, CS Lee, Gavin Lotay, CB Moon, I Nishizuka, CR Nita, Z Patel, OJ Roberts, H Schaffner, Callum Shand, H Suzuki, H Takeda, S Terashima, Z Vajta, S Kanaya, J-J Valiente-Dobón (2017)Isomer Spectroscopy of Neutron-rich 165,167Tb, In: Acta Physica Polonica B48(3)pp. 601-608

We present information on the excited states in the prolate-deformed, neutron-rich nuclei 165;167Tb100;102. The nuclei of interest were synthesised following in-flight fission of a 345 MeV per nucleon 238U primary beam on a 2 mm 9Be target at the Radioactive Ion-Beam Factory (RIBF), RIKEN, Japan. The exotic nuclei were separated and identified event-by-event using the BigRIPS separator, with discrete energy gamma-ray decays from isomeric states with half-lives in the s regime measured using the EURICA gamma-ray spectrometer. Metastable-state decays are identified in 165Tb and 167Tb and interpreted as arising from hindered E1 decay from the 7 2 [523] single quasi-proton Nilsson configuration to rotational states built on the 3 2 [411] single quasi-proton ground state. These data correspond to the first spectroscopic information in the heaviest, odd-A terbium isotopes reported to date and provide information on proton Nilsson configurations which reside close to the Fermi surface as the 170Dy doubly-midshell nucleus is approached.

AB Garnsworthy, NJ Thompson, Z Podolyak, PM Walker, SJ Williams, GD Dracoulis, G de France, GJ Lane, K Andgren, AM Bruce, AP Byrne, WN Catford, B Cederwall, GA Jones, B McGuirk, S Mandal, ES Paul, V Pucknell, N Redon, B Rosse, RJ Senior, G Sletten (2005)Spectroscopy of Po-212 and At-213 using a He-8 radioactive beam and EXOGAM, In: JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS31(10)pp. S1851-S1854
Z Podolyak, SJ Steer, S Pietri, FR Xu, HL Liu, PH Regan, D Rudolph, AB Garnsworthy, R Hoischen, M Gorska, J Gerl, HJ Wollersheim, T Kurtukian-Nieto, G Benzoni, T Shizuma, F Becker, P Bednarczyk, L Caceres, P Doornenbal, H Geissel, J Grebosz, A Kelic, I Kojouharov, N Kurz, F Montes, W Prokopowicz, T Saito, H Schaffner, S Tashenov, A Heinz, M Pfutzner, A Jungclaus, DL Balabanski, C Brandau, AM Bruce, WN Catford, IJ Cullen, Z Dombradi, E Estevez, W Gelletly, G Ilie, J Jolie, GA Jones, M Kmiecik, FG Kondev, R Kruecken, S Lalkovski, Z Liu, A Maj, S Myalski, S Schwertel, PM Walker, E Werner-Malento, O Wieland (2009)Weakly deformed oblate structures in Os-198(76)122, In: PHYSICAL REVIEW C79(3)ARTN 0pp. ?-? AMER PHYSICAL SOC
J Walshe, M Freer, C Wheldon, LN Achouri, NI Ashwood, WN Catford, IC Celik, N Curtis, F Delaunay, B Fernández-Domínguez, L Grassi, T Kokalova, M Marqués, NA Orr, L Prepolec, V Scuderi, N Soić, V Tokić (2014)The thick target inverse kinematics technique with a large acceptance silicon detector array, In: Journal of Physics: Conference Series569(1)

© Published under licence by IOP Publishing Ltd.An experimental technique for studying elastic scattering using a thick gas target is described, with a measurement of the α(24Ne,α) reaction used as an example. Advantages such as ease, detector efficiency, and the possibility of measuring the cross section at 180° in the centre-of-mass are discussed. It is shown that a resolution of tens of keV is practical at zero degrees, and that the dominant contribution to the resolution for large angles is angular straggling of the beam in the entrance window. The use of helium gas as the target allows direct measurement of a-cluster states.

NI Ashwood, M Freer, NL Achouri, TR Bloxham, WN Catford, N Curtis, PJ Haigh, CW Harlin, NP Patterson, DL Price, N Soić, JS Thomas (2009)Spectroscopy of 16O using α + 12C resonant scattering in inverse kinematics, In: Journal of Physics G: Nuclear and Particle Physics36(5)055105pp. ?-? Institute of Physics

Ameasurement of the α(12C, α) 12Creaction has been performed using resonant scattering with a gas target. Beam energies of 46, 52, 56 and 63 MeV were used to populate resonances in the excitation energy range of 11.6–22.9 MeV in 16O. The angular distributions of the elastic scattering were measured at zero degrees, using an array of segmented silicon strip detectors with a minimum range of 0◦–30◦ in the centre-of-mass. The spins of 8 resonances between 14.1 and 18.5 MeV were obtained, confirming spin assignments made using elastic scattering in normal kinematics. An R-matrix analysis of the data was performed which indicates that the present understanding of 16O in this region is good, but not complete.

Laila Gurgi, Patrick Regan, P-A Söderström, H Watanabe, Philip Walker, Zsolt Podolyak, S Nishimura, Thomas Berry, P Doornenbal, G Lorusso, T Isobe, H Baba, ZY Xu, H Sakurai, T Sumikama, Wilton Catford, AM Bruce, F Browne, GJ Lane, FG Kondev, A Odahara, J Wu, HL Liu, FR Xu, Z Korkulu, P Lee, JJ Liu, VH Phong, A Yag, GX Zhang, T Alharbi, RJ Carroll, KY Chae, Zs Dombradi, A Estrade, N Fukuda, C Griffin, E Ideguchi, N Inabe, H Kanaoka, I Kojouharov, T Kubo, S Kubono, N Kurz, I Kuti, S Lalkovski, EJ Lee, CS Lee, Gavin Lotay, C-B Moon, I Nishizuka, CR Nita, Z Patel, OJ Roberts, H Schaffner, Callum Shand, H Suzuki, H Takeda, S Terashima, Zs Vajta, S Yoshida, JJ Valiente-Dòbon (2016)Isomer spectroscopy of neutron-rich 168Tb103, In: 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 β-decay. Discrete γ-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)

N Soić, M Freer, L Donadille, NM Clarke, PJ Leask, WN Catford, KL Jones, D Mahboub, BR Fulton, BJ Greenhalgh, DL Watson (2006)Experimental evidence for cluster structure of 11B excited states, In: AIP Conference Proceedings853pp. 171-176

The kinematically complete measurements of the 7Li( 9Be,ααt)5He reaction at Ebeam = 55 and 70 MeV have been performed and the reconstructed 11B excitation energy spectra were compared with the 7Li(9Be, α7Li)5He results obtained at the same beam energies. Evidence was found for the t+8Be(g.s.) decay of the 11B excited states at 13.1 and 14.4 MeV, the α+7Li*(4.652 MeV) decay of the states at 14.4 and 17.5 MeV and for the t+ 8Be*(3.03 MeV) decay of the 17.5 MeV state in 11B. A study of the relative yields for the decay of the 14.4 MeV state indicates that significant part of α-decay strength goes into the 2α+t three-body decay channel. © 2006 American Institute of Physics.

B Fernandez-Dominguez, JS Thomas, WN Catford, F Delaunay, SM Brown, NA Orr, M Rejmund, M Labiche, M Chartier, NL Achouri, H Al Falou, NI Ashwood, D Beaumel, Y Blumenfeld, BA Brown, R Chapman, N Curtis, C Force, G de France, S Franchoo, J Guillot, P Haigh, F Hammache, V Lapoux, RC Lemmon, F Marechal, M Moro, X Mougeot, B Mouginot, L Nalpas, A Navin, N Patterson, B Pietras, EC Pollacco, A Leprince, A Ramus, JA Scarpaci, N de Sereville, I Stephan, O Sorlin, GL Wilson (2011)Emergence of the N=16 shell gap in O-21, In: PHYSICAL REVIEW C84(1)ARTN 0pp. ?-? AMER PHYSICAL SOC
WN Catford (2013)Conference summary: an experimental perspective, In: 10TH INTERNATIONAL CONFERENCE ON CLUSTERING ASPECTS OF NUCLEAR STRUCTURE AND DYNAMICS (CLUSTER'12)436UNSP 0pp. ?-? IOP PUBLISHING LTD
S Myalski, A Maj, Z Podolyak, M Kmiecik, P Bednarczyk, J Grebosz, PH Regan, AB Garnsworthy, S Pietri, D Rudolph, SJ Steer, F Becker, J Gerl, M Gorska, H Grawe, I Kojouharov, H Schaffner, HJ Wollersheim, W Prokopowicz, G Benzoni, B Blank, C Brandau, AM Bruce, L Caceres, F Camera, WN Catford, IJ Cullen, Z Dombradi, P Doornenbal, E Estevez, H Geissel, W Gelletly, A Heinz, R Hoischen, G Ilie, GA Jones, A Jungclaus, A Kelic, FG Kondev, T Kurtukian-Nieto, N Kurz, S Lalkovski, Z Liu, F Montes, M Pfuetzner, T Saito, T Shizuma, AJ Simons, S Schwertel, S Tachenov, PM Walker, E Werner-Malento, O Wieland (2012)STUDY OF ISOMER PRODUCTION RATES FOR A=142-152 AND Z=62-67 IN FRAGMENTATION OF A RELATIVISTIC Pb-208 BEAM, In: ACTA PHYSICA POLONICA B43(2)pp. 253-259 WYDAWNICTWO UNIWERSYTETU JAGIELLONSKIEGO
M Lewitowicz, JM Daugas, R Grzywacz, L Achouri, JC Angélique, D Baiborodin, R Bentida, R Béraud, C Bingham, C Borcea, W Catford, A Emsallem, G De France, M Glogowski, H Grawe, D Guillemaud-Mueller, M Houry, S Hurskanen, KL Jones, RC Lemmon, AC Mueller, A Nowak, F De Oliveira-Santos, A Płochocki, M Pfützner, PH Regan, K Rykaczewski, MG Saint-Laurent, JE Sauvestre, M Sawicka, M Schaefer, G Sletten, O Sorlin, M Stanoiu, J Szerypo, W Trinder, S Viteritti, J Winfield (1999)Study of μs-isomers in neutron-rich nuclei around Z=28 and N=40 shell closures, In: Nuclear Physics A654(1 SUPP)
SD Pain, WN Catford, NA Orr, JC Angelique, NI Ashwood, V Bouchat, NM Clarke, N Curtis, M Freer, BR Fulton, F Hanappe, M Labiche, JL Lecouey, RC Lemmon, D Mahboub, A Ninane, G Normand, N Soic, L Stuttge, CN Timis, JA Tostevin, JS Winfield, V Ziman (2006)Structure of Be-12: Intruder d-wave strength at N=8, In: PHYSICAL REVIEW LETTERS96(3)ARTN 0pp. ?-? AMER PHYSICAL SOC
JM Daugas, R Grzywacz, M Lewitowicz, L Achouri, JC Angelique, D Baiborodin, K Bennaceur, R Bentida, R Beraud, C Borcea, C Bingham, WN Catford, A Emsallem, G de France, H Grawe, KL Jones, RC Lemmon, MJL Jimenez, F Nowacki, FD Santos, M Pfutzner, PH Regan, K Rykaczewski, JE Sauvestre, M Sawicka, G Sletten, M Stanoiu (2000)The 8(+) isomer in Zn-78 and the doubly magic character of Ni-78, In: PHYSICS LETTERS B476(3-4)pp. 213-218 ELSEVIER SCIENCE BV
M Freer, NL Achouri, C Angulo, NI Ashwood, DW Bardayan, S Brown, WN Catford, KA Chipps, N Curtis, P Demaret, C Harlin, B Laurent, JD Malcolm, M Milin, T Munoz-Britton, NA Orr, SD Pain, D Price, R Raabe, N Soic, JS Thomas, C Wheldon, G Wilson, VA Ziman (2012)Resonances in (11)C observed in the (4)He((7)Be, alpha)(7)Be and (4)He((7)Be, p)(10)B reactions, In: PHYSICAL REVIEW C85ARTN 0 American Physical Society

Measurements of the 4He(7Be,α)7Be and 4He(7Be,p)10B reactions were performed using 7Be beam energies of 7.1 and 23 MeV and a helium-4 target, employing the thick target technique. Resonances were observed between Ex(11C)=8.6 to 13.8 MeV. An R-matrix analysis was performed to characterize the spins and partial widths. This analysis showed that the observed sequence of states was consistent with that found for 7Li + α resonant scattering populating resonances in 11B. A comparison of the proposed partial widths for decay with the Wigner limit indicates that several of the states are associated with cluster-like structures.

B Fernández-Domínguez, RC Lemmon, C Timis, M Labiche, WN Catford, M Chartier, NI Ashwood, N Amzal, TD Baldwin, M Burns, L Caballero, R Chapman, N Curtis, G de France, M Freer, W Gelletly, X Liang, NA Orr, SD Pain, VPE Pucknell, M Rejmund, B Rubio, H Savajols, O Sorlin, K Spohr, C Thiesen, DD Warner (2007)Single particle structure of exotic nuclei with transfer reactions, In: Progress in Particle and Nuclear Physics59(1)pp. 389-391

We report here on the first results obtained from the study of the 24Ne(d, p)25Ne reaction performed with SPIRAL beam at GANIL using the new TIARA+V AMOS+EXOGAM setup. © 2007.

C Beck, P Papka, A Sanchez i Zafraa, S Thummerer, F Azaiez, P Bednarczyk, S Courtin, D Curien, O Dorvaux, A Goasduff, D Lebhertz, A Nourreddine, M Rousseau, M-D Salsac, W von Oertzen, B Gebauer, C Wheldon, T Kokalova, G Efimov, V Zherebchevsky, C Schulz, HG Bohlen, D Kamanin, G de Angelis, A Gadea, S Lenzi, DR Napoli, S Szilner, M Milin, WN Catford, DG Jenkins, G Royer (2011)CLUSTERS IN LIGHT NUCLEI, In: ACTA PHYSICA POLONICA B42(3-4)pp. 747-756
A.  R. L Kennington, G Lotay, D. T Doherty, D Seweryniak, C Andreoiu, K Auranen, M. P Carpenter, W. N Catford, C. M Deibel, K Hadyńska-Klęk, S Hallam, D. E. M Hoff, T Huang, R. V. F Janssens, S Jazrawi, J José, F. G Kondev, T Lauritsen, J Li, A. M Rogers, J Saiz, G Savard, S Stolze, G. L Wilson, S Zhu (2020)Search for Nova Presolar Grains: $γ$-Ray Spectroscopy of 34Ar and its Relevance for the Astrophysical 33Cl($p,γ$) Reaction, In: Physical Review Letters124(25) American Physical Society (APS)

The discovery of presolar grains in primitive meteorites has launched a new era of research in the study of stellar nucleosynthesis. However, the accurate classification of presolar grains as being of specific stellar origins is particularly challenging. Recently, it has been suggested that sulfur isotopic abundances may hold the key to definitively identifying presolar grains with being of nova origins and, in this regard, the astrophysical Cl33 ( p,γ ) Ar34 reaction is expected to play a decisive role. As such, we have performed a detailed γ -ray spectroscopy study of Ar34 . Excitation energies have been measured with high precision and spin-parity assignments for resonant states, located above the proton threshold in Ar34 , have been made for the first time. Uncertainties in the Cl33 ( p,γ ) reaction have been dramatically reduced and the results indicate that a newly identified ℓ=0 resonance at Er=396.9 ( 13 ) keV dominates the entire rate for T=0.25–0.40 GK . Furthermore, nova hydrodynamic simulations based on the present work indicate an ejected S 32/ S 33 abundance ratio distinctive from type-II supernovae and potentially compatible with recent measurements of a presolar grain.

GJ Lotay, G Christian, C Ruiz, C Akers, DS Burke, WN Catford, AA Chen, D Connolly, B Davids, J Fallis, U Hager, DA Hutcheon, A Mahl, A Rojas, X Sun (2016)Direct Measurement of the Astrophysical 38Kðp;γÞ39Ca Reaction and Its Influence on theproduction of Nuclides toward the End Point of Nova Nucleosynthesis, In: Physical Review Letters116(13) American Physical Society

We have performed the first direct measurement of the 38Kðp; γÞ39Ca reaction using a beam of radioactive 38K. A proposed l ¼ 0 resonance in the 38K þ p system has been identified at 679(2) keV with an associated strength of 120 þ50 −30 meV. Upper limits of 1.16 (3.5) and 8.6 (26) meV at the 68% (95%) confidence level were also established for two further expected l ¼ 0 resonances at 386 and 515 keV, respectively. The present results have reduced uncertainties in the 38Kðp; γÞ39Ca reaction rate at temperatures of 0.4 GK by more than 2 orders of magnitude and indicate that Ar and Ca may be ejected in observable quantities by oxygen-neon novae. However, based on the newly evaluated rate, the 38Kðp; γÞ39Ca path is unlikely to be responsible for the production of Ar and Ca in significantly enhanced quantities relative to solar abundances.

RC Lemmon, B Fernandez-Dominguez, C Timis, M Labiche, WN Catford, M Chartier, N Ashwood, N Amzal, TD Baldwin, M Burns, L Caballero, R Chapman, N Curtis, G De France, M Freer, W Gelletly, X Liang, NA Orr, SD Pain, VPE Pucknell, M Rejmund, B Rubio, H Savajols, O Sorlin, K Spohr, C Thiesen, DD Warner (2006)Studies of single-particle structure in the N=16 region using transfer reactions, In: AIP Conference Proceedings853pp. 285-290

We have developed a new experimental setup based at the GANIL/SPIRAL facility in Caen, France to measure one-nucleon transfer reactions in inverse kinematics in order to study the evolution of the single particle structure of exotic nuclei. The setup couples together three state-of-the-art detection systems: the TIARA Si array, the large-acceptance magnetic spectrometer VAMOS and the high-efficiency segmented Ge γ-ray array EXOGAM. In a first experiment, the 24Ne(d,p)25Ne reaction has been studied to probe the N=16 shell closure. Details of the setup, data analysis and preliminary results are presented. © 2006 American Institute of Physics.

B Jurado, H Savajols, W Mittig, NA Orr, P Roussel-Chomaz, D Baiborodin, WN Catford, M Chartier, CE Demonchy, Z Dlouhy, A Gillibert, L Giot, A Khouaja, A Lepine-Szily, S Lukyanov, J Mrazek, YE Penionzhkevich, S Pita, M Rousseau, AC Villari (2007)Mass measurements of neutron-rich nuclei near the N=20 and 28 shell closures, In: PHYSICS LETTERS B649(1)pp. 43-48 ELSEVIER SCIENCE BV
G Christian, Gavin Lotay, C Ruiz, C Akers, D Burke, Wilton Catford, A Chen, D Connolly, B Davids, J Fallis, U Hager, D Hutcheon, A Mahl, A Rojas, X Sun (2018)Direct measurement of astrophysically important resonances in 38K( p,γ )39Ca, In: Physical Review C97(2)025802 American Physical Society

Background: Classical novae are cataclysmic nuclear explosions occurring when a white dwarf in a binary system accretes hydrogen-rich material from its companion star. Novae are partially responsible for the galactic synthesis of a variety of nuclides up to the calcium ( A ∼ 40 ) region of the nuclear chart. Although the structure and dynamics of novae are thought to be relatively well understood, the predicted abundances of elements near the nucleosynthesis endpoint, in particular Ar and Ca, appear to sometimes be in disagreement with astronomical observations of the spectra of nova ejecta. Purpose: One possible source of the discrepancies between model predictions and astronomical observations is nuclear reaction data. Most reaction rates near the nova endpoint are estimated only from statistical model calculations, which carry large uncertainties. For certain key reactions, these rate uncertainties translate into large uncertainties in nucleosynthesis predictions. In particular, the 38 K ( p , γ ) 39 Ca reaction has been identified as having a significant influence on Ar, K, and Ca production. In order to constrain the rate of this reaction, we have performed a direct measurement of the strengths of three candidate ℓ = 0 resonances within the Gamow window for nova burning, at 386 ± 10 keV, 515 ± 10 keV, and 689 ± 10 keV. Method: The experiment was performed in inverse kinematics using a beam of unstable 38 K impinged on a windowless hydrogen gas target. The 39 Ca recoils and prompt γ rays from 38 K ( p , γ ) 39 Ca reactions were detected in coincidence using a recoil mass separator and a bismuth-germanate scintillator array, respectively. Results: For the 689 keV resonance, we observed a clear recoil- γ coincidence signal and extracted resonance strength and energy values of 120 + 50 − 30 ( stat . ) + 20 − 60 ( sys . ) meV and 679 + 2 − 1 ( stat . ) ± 1 ( sys . ) keV , respectively. We also performed a singles analysis of the recoil data alone, extracting a resonance strength of 120 ± 20 ( stat . ) ± 15 ( sys . ) meV, consistent with the coincidence result. For the 386 keV and 515 keV resonances, we extract 90 % confidence level upper limits of 2.54 meV and 18.4 meV, respectively. Conclusions: We have established a new recommended 38 K ( p , γ ) 39 Ca rate based on experimental information, which reduces overall uncertainties near the peak temperatures of nova burning by a factor of ∼ 250 . Using the rate obtained in this work in model calculations of the hottest oxygen-neon novae reduces overall uncertainties on Ar, K, and Ca synthesis to factors of 15 or less in all cases.

E Clement, G De France, JM Casandjian, A Goergen, W Korten, L Bouchez, A Chatillon, A Huerstel, Y Le Coz, A Obertelli, C Theisen, JN Wilson, J-P Delaroche, M Girod, H Goutte, S Peru, T Czosnyka, J Iwanicki, PJ Napiorkowski, J Srebrny, K Wrzosek-Lipska, M Zielinska, N Bree, I Stefanescu, J Van De Walle, C Andreoiu, PA Butler, R-D Herzberg, DG Jenkins, GD Jones, A Petts, F Becker, J Gerl, WN Catford, CN Timis, G Sletten, G Georgiev, J Ljungvall (2011)EXPERIMENTAL MEASUREMENT OF THE DEFORMATION THROUGH THE ELECTROMAGNETIC PROBE: SHAPE COEXISTENCE IN EXOTIC KR AND SR ISOTOPES, In: INTERNATIONAL JOURNAL OF MODERN PHYSICS E-NUCLEAR PHYSICS20(2)pp. 415-421 WORLD SCIENTIFIC PUBL CO PTE LTD
NK Timofeyuk, B Fernandez-Dominguez, P Descouvemont, WN Catford, F Delaunay, JS Thomas (2012)Core excitations and narrow states beyond the proton dripline: The exotic nucleus Al-21, In: PHYSICAL REVIEW C86(3)ARTN 0pp. ?-? AMER PHYSICAL SOC
C Beck, ASI Zafra, P Papka, S Thummerer, F Azaiez, S Courtin, D Curien, O Dorvaux, D Lebhertz, A Nourreddine, M Rousseau, W Von Oertzen, B Gebauer, T Kokalova, C Wheldon, G De Angelis, A Gadea, S Lenzi, DR Napoli, S Szilner, WN Catford, DG Jenkins, G Royer (2009)Reaction mechanisms in 24Mg+ 12C and32S+ 24Mg, In: AIP Conference Proceedings1098pp. 207-212

The occurence of ``exotic'' shapes in light N = Z α-like nuclei is investigated for 24Mg+12C and 32S+24Mg. Various approaches of superdeformed and hyperdeformed bands associated with quasimolecular resonant structures with low spin are presented. For both reactions, exclusive data were collected with the Binary Reaction Spectrometer in coincidence with EUROBALL IV installed at the VIVITRON Tandem facility of Strasbourg. Specific structures with large deformation were selectively populated in binary reactions and their associated γ-decays studied. The analysis of the binary and ternary reaction channels is discussed.

PH Regan, AB Gamsworthy, SJ Steer, S Pletri, Z Podolyak, D Rudolph, M Gorska, L Caceres, E Wemer-Malento, J Gerl, HJ Wollersheim, F Becker, P Bednarczyk, PD Doornenbal, H Geissel, H Grawe, J Grebosz, R Hoischen, A Kelic, I Kojouharov, N Kurz, F Montes, W Prokopowicz, T Saito, H Schaffner, S Tashenov, A Heinz, M Pfuetzner, T Kurtukian-Nieto, G Benzoni, M Hellstroem, A Jungclaus, L-L Andersson, L Atanasova, DL Balabanski, MA Bentley, B Blank, A Blazhev, C Brandau, J Brown, AM Bruce, F Camera, WN Catford, IJ Cullen, Z Dombradi, E Estevez, C Fahlander, W Gelletly, G Ilie, EK Johansson, J Jolie, GA Jones, M Kmiecik, G Kondev, S Lalkovski, Z Liu, A Maj, S Myalski, S Schwertel, T Shizuma, AJ Simons, PM Walker, O Wieland (2007)First results from the stopped RISING campaign at GSI: The mapping of isomeric decays in highly exotic nuclei, In: SA Cetin, I Hikmet (eds.), Six International Conference of the Balkan Physical Union899pp. 19-22
S Calinescu, M Stanoiu, F Negoita, C Borcea, R Borcea, C Petrone, F Rotaru, L Cáceres, JC Thomas, A Lepailleur, T Roger, O Sorlin, S Grévy, D Sohler, Z Dombradi, I Kuti, Z Vajta, M Bowry, W Catford, Z Podolyak, E Wilson, S Franchoo, M Niikura, I Stefan, S Lukyanov, Y Penionzhkevich, J Mrazek, R Gillibert (2013)Study of the neutron rich sulfure isotope S through intermediate energy Coulomb excitation, In: Journal of Physics: Conference Series413(1)

The reduced transition probability B(E2: 3/2→7/2 ) has been measured in S using Coulomb excitation at intermediate energy. The nucleus of interest was produced by fragmentation of a Ca beam at GANIL. The reaction products were separated in the LISE spectrometer. After Coulomb-excitation of S in a Pb target, the γ rays emitted inflight were detected by 64 BaF detectors of the Chteau de Cristal array. The preliminary value deduced for the reduced transition probability B(E2: 3/2 →7/2 ) is in agreement with the predictions of the shell model calculations and supports a prolate-spherical shape coexistence in the S nucleus.

M Assie, JA Scarpaci, D Lacroix, JC Angelique, D Bazin, D Beaumel, Y Blumenfeld, WN Catford, M Chabot, A Chatterjee, M Fallot, H Iwasaki, F Marechal, C Monrozeau, J Nyberg, C Petrache, F Skaza, T Tuna (2010)NEUTRON CORRELATIONS IN He-6 VIEWED THROUGH NUCLEAR BREAK-UP, In: MODERN PHYSICS LETTERS A25(21-23)pp. 1846-1849
T Muñoz-Britton, M Freer, NI Ashwood, TAD Brown, WN Catford, N Curtis, SP Fox, BR Fulton, CW Harlin, AM Laird, P Mumby-Croft, ASJ Murphy, P Papka, DL Price, K Vaughan, DL Watson, DC Weisser (2010)Search for the 2+ excitation of the Hoyle state in 12C using the 12C(12C,3α)12C reaction, In: Journal of Physics G: Nuclear and Particle Physics37(10)105104
M Freer, NI Ashwood, N Curtis, JD Malcolm, T Munoz-Britton, D Price, C Wheldon, VA Ziman, NL Achouri, B Laurent, NA Orr, C Angulo, P Demaret, DW Bardayan, SD Pain, S Brown, WN Catford, C Harlin, JS Thomas, G Wilson, KA Chipps, M Milin, R Raabe, N Soić (2012)Resonances in 11C observed in the 4He(7Be,α)7Be and 4He(7Be,p)10B reactions, In: Physical Review C - Nuclear Physics85(1) American Physical Society

Measurements of the 4He(7Be,α)7Be and 4He(7Be,p)10B reactions were performed using 7Be beam energies of 7.1 and 23 MeV and a helium-4 target, employing the thick target technique. Resonances were observed between E 11C)=8.6 to 13.8 MeV. An R-matrix analysis was performed to characterize the spins and partial widths. This analysis showed that the observed sequence of states was consistent with that found for 7Li + α resonant scattering populating resonances in 11B. A comparison of the proposed partial widths for decay with the Wigner limit indicates that several of the states are associated with cluster-like structures. © 2012 American Physical Society.

S Myalski, M Kmiecik, A Maj, PH Regan, AB Garnsworthy, S Pietri, D Rudolph, Z Podolyak, SJ Steer, F Becker, P Bednarczyk, J Gerl, M Gorska, H Grawe, I Kojouharov, H Schaffner, HJ Wollersheim, W Prokopowicz, J Grebosz, G Benzoni, B Blank, C Brandau, AM Bruce, L Caceres, F Camera, WN Catford, IJ Cullen, Z Dombradi, P Doornenbal, E Estevez, H Geissel, W Gelletly, A Heinz, R Hoischen, G Ilie, GA Jones, A Jungclaus, A Kelic, FG Kondev, T Kurtukian-Nieto, N Kurz, S Lalkovski, Z Liu, F Montes, M Pfutzner, T Saito, T Shizuma, AJ Simons, S Schwertel, S Tachenov, PM Walker, E Werner-Malento, O Wieland (2007)Isomeric ratio for the I-pi=8(+) yrast state in Pd-96 produced in the relativistic fragmentation of Ag-107, In: ACTA PHYSICA POLONICA B38(4)pp. 1277-1282 ACTA PHYSICA POLONICA B, JAGELLONIAN UNIV, INST PHYSICS

We report on the preliminary results from a study of the decay of the I-pi = 8(+) T-1/2 = 2 mu s isomer in Pd-96 performed as part of the Stopped-Beam RISING campaign within the Rare Isotope Investigation at GSI (RISING). The Pd-96 ions were produced following the projectile fragmentation of a 750 MeV per nucleon Ag-107 primary beam. The reaction products were separated and identified by the in-flight method using the GSI Fragment Separator. The residues of interest were stopped in a perspex stopper surrounded by an array of 15, seven-element germanium Cluster detectors. One of the goals of the current work is to investigate the population of high-spin states produced projectile fragmentation reactions using isomeric ratio measurements to infer information on the angular momentum population distribution. In this short contribution the method and results of determining the isomeric ratio for the I-pi = 8(+) microsecond isomer in Pd-96 nucleus are presented.