Optical potential for light nuclei and momentum-space eikonal phase function

Canadian Journal of Physics - Tập 96 Số 6 - Trang 642-649 - 2018
Charles M. Werneth1, Khin Maung Maung2, Michael D. Vera2, Lawrence W. Townsend3
1NASA Langley Research Center, 2 West Reid Street, Hampton, VA 23681.
2University of Southern Mississippi, Department of Physics and Astronomy, 118 College Dr., Box 5046, Hattiesburg, MS 39406.
3University of Tennessee, Department of Nuclear Engineering, 315 Pasqua Engineering Building, Knoxville, TN 37996.

Tóm tắt

The space radiation environment comprises all of the nuclei in the periodic table with energies that extend from a fraction of an MeV/n to TeV/n. The vast range of projectile–target and energy combinations necessitates highly efficient and accurate cross section codes for use in radiation transport codes. As particles in the space radiation environment impinge on shielding materials, nuclear reactions, such as nuclear fragmentation, occur. One way of estimating nuclear fragmentation cross sections is to use an abrasion–ablation model, which describes how nucleons are dislodged from the nuclei as a result of nuclear collisions and the mechanism by which excited pre-fragments decay via particle emission to more stable states. The well-known partial wave solution method cannot be used directly for the computation of abrasion cross sections. Instead, abrasion cross sections may be computed by slightly altering the Eikonal solution method, which is a high energy (small scattering angle) approximation that depends on the nucleus–nucleus optical potential. The aim of the current work is to present two efficient methods for the computation of the Eikonal phase shift function. Analytic formulas of the optical potential are presented in the position-space representation for nuclei that are well-represented by harmonic-well nuclear matter densities (A < 20), which reduces the Eikonal phase factor to an integration over a single dimension. Next, the Eikonal phase function is presented in the momentum-space representation, which is particularly useful when the Fourier transform of the position-space optical potential is known. These new methods increase the computational efficiency by three orders of magnitude and allow for rapid prediction of elastic differential, total, elastic, and reaction cross sections in the Eikonal approximation.

Từ khóa


Tài liệu tham khảo

10.1016/S0168-583X(01)00748-0

10.1126/science.1231160

10.1146/annurev.ns.33.120183.001543

10.1016/j.jcp.2010.09.010

10.1016/j.asr.2010.03.005

C.J. Joachain. Quantum Collision Theory. American Elsevier, New York, N.Y., 1983.

10.1016/j.nimb.2013.05.003

10.1103/PhysRevC.90.064905

Werneth C.M., 2013, Phys. Lett. B, 233, 464

Werneth C.M., 2017, Nucl. Instr. Methods in Phys. Res. B, 392, 74, 10.1016/j.nimb.2016.12.009

10.1016/j.nima.2012.10.027

10.1016/S0168-583X(98)00957-4

10.1139/p83-106

10.1103/PhysRev.89.575

10.1016/0003-4916(58)90007-1

10.1016/0003-4916(62)90221-X

D.H. Wolfe. Studies of the nucleon-nucleus first order optical potential. Ph.D. thesis, Kent State University, 1983.

10.1103/PhysRevC.30.1861

10.1016/S0092-640X(74)80002-1

10.1016/0092-640X(87)90013-1

10.1139/p82-204

10.1139/p83-015

Wilson J.W., 1974, Phys. Lett. B, 52, 419, 10.1016/0370-2693(74)90074-4

10.1139/p81-207

10.1103/PhysRevC.43.2103

10.1016/S0375-9474(99)00856-8

10.1103/PhysRevC.43.1272

10.1016/0375-9474(72)90207-2

Thông tin
Thông tin xuất bản

Canadian Journal of Physics

Tập 96 Số 6

642-649

Thông tin tác giả