Characterization of Secondary Neutron Spectra from Therapeutic Proton and Carbon Ion Beams Using PHITS Simulation

Hadron therapy (HT) is a technique that uses accelerated ions, notably protons, and carbon ions, to destroy tumors. It has demonstrated high success rates in the treatment of certain cancers resistant to irradiation. In HT, the majority of the dose is delivered to the tumor volume by electromagnetic interactions with atomic electrons. However, it is important to note that the primary particles used in HT can induce nuclear reactions, generating undesirable secondary radiation, certainly neutrons. As a result, a significant portion of the patients’ body may be exposed to the secondary background radiation field. Thus, these unwanted secondary neutrons should be evaluated. The purpose of this research in first is to characterize the secondary neutron production (SNP) during the administration of Hadrons with energies 140 MeV proton, and 264 MeV/u carbon ions ( C) in a soft tissue phantom. Second, comparing the neutron spectrum for different angles for protons and carbon ions for carbon targets to experimental data. Our results show that the neutron spectra (thick target neutron yields TTNYs ) at energies less than 20 MeV, using the INCL4.6/GEM models and JQMD/GEM across a wide range would be suitable for the Monte Carlo transport simulation.