Exponential discontinuous finite element solution of high-energy coupled proton-neutron transport equations
The authors consider the application of the nonlinear exponential discontinuous scheme to coupled proton-neutron transport. A monoenergetic primary proton beam of relativistic energy interacts with an amorphous target through continuous slowing down (CSD) and inelastic nuclear interactions, generating a proton-neutron cascade that is quenched when absorption becomes significant at lower energies. An important and interesting aspect of this problem is that while the primary protons range-out at a certain depth by virtue of CSD, penetrating secondary neutrons deliver charge and dose at locations otherwise inaccessible to primary protons. A deterministic transport description in the straight-ahead approximation, an extremely used model, is employed here to study this problem. The nonlinear exponential discontinuous scheme is very effective in neutral particle transport, yielding positive and accurate discretizations even for very crude cells. However, in direct application of this method to monoenergetic charged particles with CSD, the exponential discontinuous scheme produces numerically highly straggled, step method-like solutions, demonstrating the inability of this scheme to describe sharply varying solutions. However, isolating and treating the primary proton distribution exactly removes this difficulty.
- Research Organization:
- Univ. of New Mexico, Albuquerque, NM (US)
- OSTI ID:
- 20104467
- Journal Information:
- Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 82; ISSN 0003-018X; ISSN TANSAO
- Country of Publication:
- United States
- Language:
- English
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