title: 3DHZETRN: Shielded ICRU spherical phantom.
abstract: A computationally efficient 3DHZETRN code capable of simulating High (H) Charge (Z) and Energy (HZE) and light ions (including neutrons) under space-like boundary conditions with enhanced neutron and light ion propagation was recently developed for a simple homogeneous shield object. Monte Carlo benchmarks were used to verify the methodology in slab and spherical geometry, and the 3D corrections were shown to provide significant improvement over the straight-ahead approximation in some cases. In the present report, the new algorithms with well-defined convergence criteria are extended to inhomogeneous media within a shielded tissue slab and a shielded tissue sphere and tested against Monte Carlo simulation to verify the solution methods. The 3D corrections are again found to more accurately describe the neutron and light ion fluence spectra as compared to the straight-ahead approximation. These computationally efficient methods provide a basis for software capable of space shield analysis and optimization.
authors.affiliation: Old Dominion University, Norfolk, VA 23529, USA.
authors.forename: John W
authors.initials: JW
authors.lastname: Wilson
authors.affiliation: NASA Langley Research Center, 2 West Reid St., Mail stop 188E, Hampton, VA 23681-2199, USA. Electronic address: Tony.C.Slaba@nasa.gov.
authors.forename: Tony C
authors.initials: TC
authors.lastname: Slaba
authors.affiliation: Old Dominion University, Norfolk, VA 23529, USA.
authors.forename: Francis F
authors.initials: FF
authors.lastname: Badavi
authors.affiliation: NASA Johnson Space Center, Houston, TX 77004, USA.
authors.forename: Brandon D
authors.initials: BD
authors.lastname: Reddell
authors.affiliation: NASA Johnson Space Center, Houston, TX 77004, USA.
authors.forename: Amir A
authors.initials: AA
authors.lastname: Bahadori
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D005118:Extraterrestrial Environment; D008962:Models, Theoretical; D009010:Monte Carlo Method; D009502:Neutrons / Q000009:adverse effects; D019047:Phantoms, Imaging; D011482:Protective Devices; D011522:Protons; D011835:Radiation Protection / Q000295:instrumentation / Q000379:methods*; D013026:Space Flight; D018561:Space Simulation
chemical_list: D011522:Protons
keywords: HZETRN; Radiation shielding; Radiation transport; Space radiation