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Dr Edward Simpson

Research Fellow

Email:
Phone: Work: 01483 68 6795
Room no: 15 BB 03

Further information

Biography

Edward received his MPhys Physics with Nuclear Astrophysics from the University of Surrey in 2006, having spent a year at the Joint Institute for Nuclear Astrophysics at the University of Notre Dame in Indiana.  His PhD work on two-nucleon knockout reactions was completed in 2009, again at the University of Surrey, where he has since held a postdoctoral research position.  His current research focuses on reactions with deformed nuclei.

Publications

Highlights

  • Adelberger EG, Garcia A, Robertson RGH, Snover KA, Balantekin AB, Heeger K, Ramsey-Musolf MJ, Bemmerer D, Junghans A, Bertulani CA, Chen J-W, Costantini H, Prati P, Couder M, Uberseder E, Wiescher M, Cyburt R, Davids B, Freedman SJ, Gai M, Gazit D, Gialanella L, Imbriani G, Greife U, Hass M, Haxton WC, Itahashi T, Kubodera K, Langanke K, Leitner D, Leitner M, Vetter P, Winslow L, Marcucci LE, Motobayashi T, Mukhamedzhanov A, Tribble RE, Nollett KM, Nunes FM, Park T-S, Parker PD, Schiavilla R, Simpson EC, Spitaleri C, Strieder F, Trautvetter H-P, Suemmerer K, Typel S. (2011) 'Solar fusion cross sections. II. The pp chain and CNO cycles'. AMER PHYSICAL SOC REVIEWS OF MODERN PHYSICS, 83 (1), pp. 195-245.
    doi: 10.1103/RevModPhys.83.195
    Full text is available at: http://epubs.surrey.ac.uk/28860/
  • Simpson EC, Tostevin JA. (2010) 'Correlations probed in direct two-nucleon removal reactions'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 82 (4) Article number ARTN 044616
    doi: 10.1103/PhysRevC.82.044616
    Full text is available at: http://epubs.surrey.ac.uk/7337/
  • Simpson EC, Tostevin JA, Podolyak Z, Regan PH, Steer SJ. (2009) 'Population of low-seniority isomeric states of Hg-206 by two-proton knockout reactions at relativistic energies'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 80 (6) Article number ARTN 064608
    doi: 10.1103/PhysRevC.80.064608
    Full text is available at: http://epubs.surrey.ac.uk/7344/
  • Simpson EC, Tostevin JA, Bazin D, Brown BA, Gade A. (2009) 'Two-Nucleon Knockout Spectroscopy at the Limits of Nuclear Stability'. AMER PHYSICAL SOC PHYSICAL REVIEW LETTERS, 102 (13) Article number ARTN 132502
    doi: 10.1103/PhysRevLett.102.132502
    Full text is available at: http://epubs.surrey.ac.uk/7351/

Journal articles

  • Simpson EC, Navratil P, Roth R, Tostevin JA. (2012) 'Microscopic two-nucleon overlaps and knockout reactions from 12C'. American Physical Society Physical Review C: Nuclear Physics, 86 (5) Article number 054609
    doi: 10.1103/PhysRevC.86.054609
    Full text is available at: http://epubs.surrey.ac.uk/741467/

    Abstract

    The nuclear structure dependence of direct reactions that remove a pair of like or unlike nucleons from a fast 12C projectile beam are considered. Specifically, we study the differences in the two-nucleon correlations present and the predicted removal cross sections when using p-shell shell-model and multi-ℏω no-core shell-model (NCSM) descriptions of the two-nucleon overlaps for the transitions to the mass A=10 projectile residues. The NCSM calculations use modern chiral two-nucleon and three-nucleon (NN+3N) interactions. The np-removal cross sections to low-lying T=0, 10B final states are enhanced when using the NCSM two-nucleon amplitudes. The calculated absolute and relative partial cross sections to the low-energy 10B final states show a significant sensitivity to the interactions used, suggesting that assessments of the overlap functions for these transitions and confirmations of their structure could be made using final-state-exclusive measurements of the np-removal cross sections and the associated momentum distributions of the forward traveling projectile-like residues.

  • Wimmer K, Bazin D, Gade A, Tostevin JA, Baugher T, Chajecki Z, Coupland D, Famiano MA, Ghosh TK, Grinyer GF, Hodges R, Howard ME, Kilburn M, Lynch WG, Manning B, Meierbachtol K, Quarterman P, Ratkiewicz A, Sanetullaev A, Simpson EC, Stroberg SR, Tsang MB, Weisshaar D, Winkelbauer J, Winkler R, Youngs M. (2012) 'Correlations in intermediate-energy two-proton removal reactions'. American Physical Society Physical Review Letters, 109 (20) Article number 202505
    doi: 10.1103/PhysRevLett.109.202505
    Full text is available at: http://epubs.surrey.ac.uk/739220/

    Abstract

    We report final-state-exclusive measurements of the light charged fragments in coincidence with 26Ne residual nuclei following the direct two-proton removal from a neutron-rich 28Mg secondary beam. A Dalitz-plot analysis and comparisons with simulations show that a majority of the triple-coincidence events with two protons display phase-space correlations consistent with the (two-body) kinematics of a spatially correlated pair-removal mechanism. The fraction of such correlated events, 56(12)%, is consistent with the fraction of the calculated cross section, 64%, arising from spin S=0 two-proton configurations in the entrance-channel (shell-model) 28Mg ground state wave function. This result promises access to an additional and more specific probe of the spin and spatial correlations of valence nucleon pairs in exotic nuclei produced as fast secondary beams.

  • Simpson EC, Tostevin JA. (2012) 'Projectile deformation effects on single-nucleon removal reactions'. Physical Review C: Nuclear Physics, 86 (5) Article number 054603
    doi: 10.1103/PhysRevC.86.054603
    Full text is available at: http://epubs.surrey.ac.uk/736611/

    Abstract

    We discuss intermediate-energy single-nucleon removal reactions from deformed projectile nuclei. The removed nucleon is assumed to originate from a given Nilsson model single-particle state and the inclusive cross sections, to all rotational states of the residual nucleus, are calculated. We investigate the sensitivity of both the stripping cross sections and their momentum distributions to the assumed size of the model space in the Nilsson model calculations and to the shape of the projectile and residue. We show that the cross sections for small deformations follow the decomposition of the Nilsson state in a spherical basis. In the case of large and prolate projectile deformations the removal cross sections from prolate-like Nilsson states, having large values for the asymptotic quantum number nz, are reduced. For oblate-like Nilsson states, with small nz, the removal cross sections are increased. Whatever the deformation, the residue momentum distributions are found to remain robustly characteristic of the orbital angular momentum decomposition of the initial state of the nucleon in the projectile.

  • Kobayashi N, Nakamura T, Tostevin JA, Kondo Y, Aoi N, Baba H, Deguchi S, Gibelin J, Ishihara M, Kawada Y, Kubo T, Motobayashi T, Ohnishi T, Orr NA, Otsu H, Sakurai H, Satou Y, Simpson EC, Sumikama T, Takeda H, Takechi M, Takeuchi S, Tanaka KN, Tanaka N, Togano Y, Yoneda K. (2012) 'One- and two-neutron removal reactions from the most neutron-rich carbon isotopes'. Physical Review C: Nuclear Physics, 86 (5) Article number 054604
    doi: 10.1103/PhysRevC.86.054604
    Full text is available at: http://epubs.surrey.ac.uk/736612/

    Abstract

    The structure of 19,20,22C has been investigated using high-energy (around 240 MeV/nucleon) one- and two-neutron removal reactions on a carbon target. Measurements were made of the inclusive cross sections and momentum distributions for the charged residues. Narrow momentum distributions were observed for one-neutron removal from 19C and 20C and two-neutron removal from 22C. Two-neutron removal from 20C resulted in a relatively broad momentum distribution. The results are compared with eikonal-model calculations combined with shell-model structure information. The neutron removal cross sections and associated momentum distributions are calculated for transitions to both the particle-bound and particle-unbound final states. The calculations take into account the population of the mass A−1 reaction residues A−1C and, following one-neutron emission after one-neutron removal, the mass A−2 two-neutron removal residues A−2C. The smaller contributions of direct two-neutron removal, that populate the A−2C residues in a single step, are also computed. The data and calculations are shown to be in good overall agreement and consistent with the predicted shell-model ground-state configurations and one-neutron overlaps with low-lying states in 18−21C. These suggest significant νs1/22 valence neutron configurations in both 20C and 22C. The results for 22C strongly support the picture of 22C as a two-neutron halo nucleus with a dominant νs1/22 ground-state configuration.

  • 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'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 85 (6) Article number ARTN 064303
    doi: 10.1103/PhysRevC.85.064303
    Full text is available at: http://epubs.surrey.ac.uk/727807/
  • Mason PJR, Alharbi T, Regan PH, Podolyàk Z, Bowry M, Nakhostin M, Simpson EC, Alharbi T, Mrginean N, Bucurescu D, Cta-Danil G, Cta-Danil I, Deleanu D, Filipescu D, Glodariu T, Ghiţ D, Mrginean R, Mihai C, Negret A, Pascu S, Sava T, Stroe L, Suliman G, Zamfir NV, Alkhomashi N, Bender PC, Bostan M, Kusoglu A, Bruce AM, Triguero CR, Erduran MN, Chakrabarti R, Ghugre SS, Detistov P, Garg U, Sinha AK. (2012) 'Half-life of the I 4 intruder state in P using LaBr :Ce fast timing'. Journal of Physics: Conference Series, 381 (1)
    doi: 10.1088/1742-6596/381/1/012063
  • Simpson EC. (2012) 'Spectroscopy and correlations probed in direct two-nucleon knockout reactions'. Journal of Physics: Conference Series, 381 (1)
    doi: 10.1088/1742-6596/381/1/012108
  • Santiago-Gonzalez D, Wiedenhoever I, Abramkina V, Avila ML, Baugher T, Bazin D, Brown BA, Cottle PD, Gade A, Glasmacher T, Kemper KW, McDaniel S, Rojas A, Ratkiewicz A, Meharchand R, Simpson EC, Tostevin JA, Volya A, Weisshaar D. (2011) 'Triple configuration coexistence in S-44'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 83 (6) Article number ARTN 061305
    doi: 10.1103/PhysRevC.83.061305
    Full text is available at: http://epubs.surrey.ac.uk/7332/
  • Adelberger EG, Garcia A, Robertson RGH, Snover KA, Balantekin AB, Heeger K, Ramsey-Musolf MJ, Bemmerer D, Junghans A, Bertulani CA, Chen J-W, Costantini H, Prati P, Couder M, Uberseder E, Wiescher M, Cyburt R, Davids B, Freedman SJ, Gai M, Gazit D, Gialanella L, Imbriani G, Greife U, Hass M, Haxton WC, Itahashi T, Kubodera K, Langanke K, Leitner D, Leitner M, Vetter P, Winslow L, Marcucci LE, Motobayashi T, Mukhamedzhanov A, Tribble RE, Nollett KM, Nunes FM, Park T-S, Parker PD, Schiavilla R, Simpson EC, Spitaleri C, Strieder F, Trautvetter H-P, Suemmerer K, Typel S. (2011) 'Solar fusion cross sections. II. The pp chain and CNO cycles'. AMER PHYSICAL SOC REVIEWS OF MODERN PHYSICS, 83 (1), pp. 195-245.
    doi: 10.1103/RevModPhys.83.195
    Full text is available at: http://epubs.surrey.ac.uk/28860/
  • Avgoulea M, Gangrsky YP, Marinova KP, Zemlyanoi SG, Fritzsche S, Iablonskyi D, Barbieri C, Simpson EC, Stevenson PD, Billowes J, Campbell P, Cheal B, Tordoff B, Bissell ML, Forest DH, Gardner MD, Tungate G, Huikari J, Nieminen A, Penttila H, Aysto J. (2011) 'Nuclear charge radii and electromagnetic moments of radioactive scandium isotopes and isomers'. IOP PUBLISHING LTD JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS, 38 (2) Article number ARTN 025104
    doi: 10.1088/0954-3899/38/2/025104
    Full text is available at: http://epubs.surrey.ac.uk/7774/
  • Simpson EC, Tostevin JA. (2011) 'Two-nucleon correlation effects in knockout reactions from C-12'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 83 (1) Article number ARTN 014605
    doi: 10.1103/PhysRevC.83.014605
    Full text is available at: http://epubs.surrey.ac.uk/7336/
  • Simpson EC, Tostevin JA. (2010) 'Correlations probed in direct two-nucleon removal reactions'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 82 (4) Article number ARTN 044616
    doi: 10.1103/PhysRevC.82.044616
    Full text is available at: http://epubs.surrey.ac.uk/7337/
  • Simpson EC, Tostevin JA, Podolyak Z, Regan PH, Steer SJ. (2010) 'Differential isomeric ratios following two-proton knockout from Pb-208'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 82 (3) Article number ARTN 037602
    doi: 10.1103/PhysRevC.82.037602
    Full text is available at: http://epubs.surrey.ac.uk/7338/
  • Azuma RE, Uberseder E, Simpson EC, Brune CR, Costantini H, de Boer RJ, Goerres J, Heil M, LeBlanc PJ, Ugalde C, Wiescher M. (2010) 'AZURE: An R-matrix code for nuclear astrophysics'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 81 (4) Article number ARTN 045805
    doi: 10.1103/PhysRevC.81.045805
    Full text is available at: http://epubs.surrey.ac.uk/28858/
  • Costantini H, deBoer RJ, Azuma RE, Couder M, Goerres J, Hammer JW, LeBlanc PJ, Lee HY, O'Brien S, Palumbo A, Simpson EC, Stech E, Tan W, Uberseder E, Wiescher M. (2010) 'O-16(alpha,gamma)Ne-20 S factor: Measurements and R-matrix analysis'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 82 (3) Article number ARTN 035802
    doi: 10.1103/PhysRevC.82.035802
    Full text is available at: http://epubs.surrey.ac.uk/28859/
  • Simpson EC, Tostevin JA, Podolyak Z, Regan PH, Steer SJ. (2009) 'Population of low-seniority isomeric states of Hg-206 by two-proton knockout reactions at relativistic energies'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 80 (6) Article number ARTN 064608
    doi: 10.1103/PhysRevC.80.064608
    Full text is available at: http://epubs.surrey.ac.uk/7344/
  • Simpson EC, Tostevin JA, Bazin D, Gade A. (2009) 'Longitudinal momentum distributions of the reaction residues following fast two-nucleon knockout reactions'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 79 (6) Article number ARTN 064621
    doi: 10.1103/PhysRevC.79.064621
    Full text is available at: http://epubs.surrey.ac.uk/7348/
  • Simpson EC, Tostevin JA, Bazin D, Brown BA, Gade A. (2009) 'Two-Nucleon Knockout Spectroscopy at the Limits of Nuclear Stability'. AMER PHYSICAL SOC PHYSICAL REVIEW LETTERS, 102 (13) Article number ARTN 132502
    doi: 10.1103/PhysRevLett.102.132502
    Full text is available at: http://epubs.surrey.ac.uk/7351/
  • Simpson EC, Tostevin JA. (2009) 'One- and two-neutron removal from the neutron-rich carbon isotopes'. AMER PHYSICAL SOC PHYSICAL REVIEW C, 79 (2) Article number ARTN 024616
    doi: 10.1103/PhysRevC.79.024616
    Full text is available at: http://epubs.surrey.ac.uk/7352/
  • Simpson EC, Azuma RE, Wiescher M, Champagne A, Bertone P, Trautvetter H-P, Görres J, Ugalde C. (2006) 'Multichannel R-matrix analysis of CNO cycle reactions'. American Institute of Physics AIP Conference Proceedings, 819, pp. 599-600.
    doi: 10.1063/1.2187936
    Full text is available at: http://epubs.surrey.ac.uk/28861/