Simulation of ¹⁶O-ion fragmentation at 0.6 and 1 GEV/U

Fragmentation of energetic ¹⁶O ions in carbon- and hydrogen-rich materials was simulated with the Quantum Molecular Dynamic-based Monte Carlo code PHITS [1]. The simulation results are compared with measurements recently conducted at the NASA Space Radiation Laboratory at Brookhaven National Laboratory [2]. The experimental layout is shown schematically in Fig. 1. A beam of ¹⁶O with energies of either 0.6 or 1 GeV/u passes through a target and a series of thin lithium-drifted silicon detectors. The detectors upstream of the target serve to identify the ¹⁶O-beam ions and provide the "event trigger" for measuring the energy deposition in the downstream detectors used to identify the fragments. The simulations modeled the experiment; however, the flux of fragments was tallied directly using volume-averaged and surface-crossing flux tallies. No attempt was made at this time to correct the calculations for background contributions due to fragmentation in the detectors or for the near-simultaneous passages of two or more ions through the detectors. Initial results presented in Fig. 2 show good agreement of the simulations with the experiments. Relative ion fluxes are compared for two targets: polyethylene-infiltrated (PE) low-density carbon foam at thickness 4.998 g cm^-2 in 0.6-GeV ¹⁶O beam and a Kevlar target at thickness 4.184-g cm^-2 in 0.6- and 1-GeV ¹⁶O beams.