Benchmark of neutron production cross sections with Monte Carlo codes

作者：Tsai Pi En; Lai Bo Lun; Heilbronn Lawrence H^*; Sheu Rong Jiun

来源：Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms , 2018, 416: 16-29.

DOI：10.1016/j.nimb.2017.11.029

• Neutron production cross sections
• PHITS
• FLUKA
• MCNP

Aiming to provide critical information in the fields of heavy ion therapy, radiation shielding in space, and facility design for heavy-ion research accelerators, the physics models in three Monte Carlo simulation codes - PHITS, FLUKA, and MCNP6, were systematically benchmarked with comparisons to fifteen sets of experimental data for neutron, production cross sections, which include various combinations of C-12, Ne-20, Ar-40, Kr-84 and Xe-132 projectiles and Li-nat, C-nat, Al-nat, Cu-nat, and Pb-nat target nuclides at incident energies between 135 MeV/nucleon and 600 MeV/nucleon.
For neutron energies above 60% of the specific projectile energy per nucleon, the LAQGMS03.03 in MCNP6, the JQMD/JQMD-2.0 in PHITS, and the RQMD-2.4 in FLUKA all show a better agreement with data in heavy projectile systems than with light-projectile systems, suggesting that the collective properties of projectile nuclei and nucleon interactions in the nucleus should be considered for light projectiles. For intermediate-energy neutrons whose energies are below the 60% projectile energy per nucleon and above 20 MeV, FLUKA is likely to overestimate the secondary neutron production, while MCNP6 tends towards underestimation. PHITS with JQMD shows a mild tendency for underestimation, but the JQMD-2.0 model with a modified physics description for central collisions generally improves the agreement between data and calculations. For low-energy neutrons (below 20 MeV), which are dominated by the evaporation mechanism, PHITS (which uses GEM linked with JQMD and JQMD-2.0) and FLUKA both tend to overestimate the production cross section, whereas MCNP6 tends to underestimate more systems than to overestimate. For total neutron production cross sections, the trends of the benchmark results over the entire energy range are similar to the trends seen in the dominate energy region. Also, the comparison of GEM coupled with either JQMD or JQMD-2.0 in the PHITS code indicates that the model used to describe the first stage of a nucleus-nucleus collision also affects the low-energy neutron production. Thus, in this case, a proper combination of two physics models is desired to reproduce the measured results. In addition, code users should be aware that certain models consistently produce secondary neutrons within a constant fraction of another model in certain energy regions, which might be correlated to different physics treatments in different models.

• 出版日期2018-2-1
• 单位清华大学