PHITS – benchmark of partial charge-changing cross sections for intermediate-mass systems

The PHITS (Particle and Heavy Ion Transport System) code is a three-dimensional Monte Carlo code that is able to simulate the transport of nuclei and other particles in complicated geometries and calculate fluxes, doses, energy-deposition distributions and many other observables. Among its many possible fields of application, it can be used e.g. to design and optimise radiation shields for space vessels. However, the reliability of the predictions of the code depends directly on the certified accuracy of the code components, i.e. the models the code uses to estimate the quantities necessary for the transport calculation. As a part of a comprehensive benchmarking program, we have investigated the possibility of using PHITS to calculate partial charge-changing cross sections and we have compared the results with measurements performed by some of us (CZ, LH, JM, SG). The results, although limited, suggest that the current reaction-cross-section models might be inadequate for use in space radioprotection; we therefore claim the need for a thorough benchmarking of the models and for new reaction-cross-section measurements and experimental techniques.