DOI: 10.29130/dubited.1945966 ISSN: 2148-2446

Comprehensive Analysis of Particle Production, Transport, and Spatial Dose Distribution in Two Multilayer Shielding Designs for a 50 MeV Proton Accelerator Using FLUKA Monte Carlo Simulations

Demet Sariyer
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This study investigates secondary particle production and transport processes in two different multilayer shielding configurations (Design 1 and Design 2) for a 50 MeV proton accelerator using the FLUKA Monte Carlo (MC) code. A monoenergetic proton beam interacting with a copper target generates a complex radiation field composed of photons, neutrons, protons, and light nuclear particles. Analysis of inelastic interactions shows that photon production is dominant in both designs at approximately 50%, followed by neutrons (~27%) and protons (~17%), indicating the significant role of electromagnetic processes in the low-energy regime. Stopping particle statistics reveal that nearly 99% of primary protons are absorbed within the shielding structures, while the contribution of light ions remains negligible. The investigation of low-energy neutron interactions demonstrates a strong neutron multiplication behavior, with more than 97% of the generated secondary particles being neutrons. Although both shielding designs exhibit similar overall particle production characteristics, Design 1 yields a slightly higher neutron multiplication factor (~4.16 particles per proton) compared to Design 2 (~3.74 particles per proton), suggesting that Design 2 provides relatively more effective moderation for low-energy neutrons. These findings indicate that while initial particle production is governed by electromagnetic interactions, the evolution of the radiation field is primarily controlled by neutron transport and multiplication mechanisms. Furthermore, one-dimensional ambient dose equivalent H*(10) profiles along the x and y directions clearly demonstrate the directional attenuation performance of the shielding configurations. In addition, relative error distributions obtained from MC simulations were analyzed to assess computational reliability, confirming that the majority of dose results fall within acceptable uncertainty limits (generally below 10%). Overall, the study provides a detailed physical interpretation of particle production mechanisms and dose distribution characteristics, offering valuable insights for the optimization of multilayer shielding designs in low-energy proton accelerator environments.

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