Monte Carlo simulations of PVC films loaded with microparticles of MgB4O7 to detect albedo neutrons

Measurements of entrance doses and extremity doses in mix fields are quite complex, particularly when it comes to neutron radiation. For this reason, films of transparent and flexible polymers loaded with luminescent materials sensitive to photons and neutrons were developed experimentally. However, there is a demand for optimizing the shape and arrangement of the crystals in these films. Using Monte Carlo simulations with the PHITS code, we simulated a geometry so that it would be possible to measure the dose deposited by the primary neutrons and by neutrons scattered backwards by a water phantom. We evaluated the sensitivity of the films loaded with MgB4O7 produced with different boron isotopes. We found that, in the case of a photon source, the energy deposited in the MgB4O7 particles comes from the photons that directly impact the film and that there was no significant difference in sensitivity for the different isotopes. However, using neutron beams, the water phantom is responsible for backscattering the neutrons that deposit the dose in the film produced with B-10, indicating that films can be used to detect albedo neutrons from an irradiated body and differentiate them from gamma irradiation.