Describing Neutron Transfer Reactions
for Deformed Nuclei with a Sturmian
Basis
V. G. Gueorguiev, J. E. Escher, F. S. Dietrich, and P. D. Kunz
We investigate the spin–parity distribution P(J π ,E) of those 156 Gd states above the
neutron separation energy S n = 8.536 MeV [1] that are expected to be populated
via the neutron pickup reaction 157 Gd( 3 He, 4 He) 156 Gd. Investigating such onenucleon transfer reactions is important for applications of the surrogate reaction
method, an indirect approach for determining hard-to-measure compound cross
sections [2]. In a surrogate reaction experiment, a charged-particle transfer or
inelastic scattering reaction is employed to produce a compound nucleus, observe
its decay, and use the decay observations to constrain Hauser-Feshbach calculations
of a reaction that proceeds through the same compound nucleus but cannot be
measured directly, e.g., neutron capture on a short-lived isotope [3, 4]. Unlike the
compound-nuclear reaction of interest, the surrogate reaction is a direct reaction that
produces a doorway state, which subsequently damps into the relevant compound
nucleus. To fully utilize the surrogate approach, it is necessary to calculate the
probabilities P(J π ,E) for producing states with specific spin and parity, J π , at
high excitation energies E, typically around the neutron separation energy [5].
Here, we investigate the spin–parity distribution P(J π ,E) of 156 Gd produced via the
neutron pickup reaction 157 Gd( 3 He, 4 He) 156 Gd. In our initial treatment, we restrict
our considerations to a one-step reaction mechanism and focus on the effect of
V. G. Gueorguiev ()
Institute for Advanced Physical Studies, Sofia, Bulgaria
Ronin Institute for Independent Scholarship, Montclair, NJ, USA
e-mail: Vesselin@MailAPS.org
J. E. Escher · F. S. Dietrich
Lawrence Livermore National Laboratory, Livermore, CA, USA
P. D. Kunz
Department of Physics and Astrophysics, University of Colorado, Boulder, CO, USA
© This is a U.S. government work and not under copyright protection
in the U.S.; foreign copyright protection may apply 2021
J. Escher et al. (eds.), Compound-Nuclear Reactions, Springer Proceedings in
Physics 254, https://doi.org/10.1007/978-3-030-58082-7_29
233
for Deformed Nuclei with a Sturmian
Basis
V. G. Gueorguiev, J. E. Escher, F. S. Dietrich, and P. D. Kunz
We investigate the spin–parity distribution P(J π ,E) of those 156 Gd states above the
neutron separation energy S n = 8.536 MeV [1] that are expected to be populated
via the neutron pickup reaction 157 Gd( 3 He, 4 He) 156 Gd. Investigating such onenucleon transfer reactions is important for applications of the surrogate reaction
method, an indirect approach for determining hard-to-measure compound cross
sections [2]. In a surrogate reaction experiment, a charged-particle transfer or
inelastic scattering reaction is employed to produce a compound nucleus, observe
its decay, and use the decay observations to constrain Hauser-Feshbach calculations
of a reaction that proceeds through the same compound nucleus but cannot be
measured directly, e.g., neutron capture on a short-lived isotope [3, 4]. Unlike the
compound-nuclear reaction of interest, the surrogate reaction is a direct reaction that
produces a doorway state, which subsequently damps into the relevant compound
nucleus. To fully utilize the surrogate approach, it is necessary to calculate the
probabilities P(J π ,E) for producing states with specific spin and parity, J π , at
high excitation energies E, typically around the neutron separation energy [5].
Here, we investigate the spin–parity distribution P(J π ,E) of 156 Gd produced via the
neutron pickup reaction 157 Gd( 3 He, 4 He) 156 Gd. In our initial treatment, we restrict
our considerations to a one-step reaction mechanism and focus on the effect of
V. G. Gueorguiev ()
Institute for Advanced Physical Studies, Sofia, Bulgaria
Ronin Institute for Independent Scholarship, Montclair, NJ, USA
e-mail: Vesselin@MailAPS.org
J. E. Escher · F. S. Dietrich
Lawrence Livermore National Laboratory, Livermore, CA, USA
P. D. Kunz
Department of Physics and Astrophysics, University of Colorado, Boulder, CO, USA
© This is a U.S. government work and not under copyright protection
in the U.S.; foreign copyright protection may apply 2021
J. Escher et al. (eds.), Compound-Nuclear Reactions, Springer Proceedings in
Physics 254, https://doi.org/10.1007/978-3-030-58082-7_29
233