Radiological protection study of a radioisotope production scenario of a laser-based proton accelerator

One of the most attractive applications of laser-based particle accelerators is the on-site generation of radioisotopes. Laser-accelerated protons can be used as projectiles to induce nuclear reactions in a suitable target material. Our group has studied in detail the different sources of risk existing in a realistic production scenario. The first step addresses the laser-target interaction that involves the proton generation and the accompanying multi-MeV electrons. In the second one, the laser-accelerated protons are guided to the secondary target to induce the specific nuclear reaction. An analytic-quantitative estimation of equivalent dose has been calculated. We have selected a set of broad electron energy spectra following a Boltzmann distribution for energies from 0.5 MeV to 20 MeV. The total number of electrons is 10 11 per shot. The scenario of radioisotope production requires 30 minutes of irradiation at 100 Hz repetition rate. In addition, a Montecarlo simulation has been performed simulating the same scenario in order to obtain a 3D dosimetric map of the surrounding areas. The deposited dose due to the activity of the radioisotope has been calculated analytically for the nuclear reaction 11 B(p,n) 11 C assuming a linear activity increase to 0.5 GBq during the irradiation time. This process will generate a total number of neutrons around 5 · 10 9 . A Montecarlo simulation to estimate their dosimetric impact has been performed as well.