Simulations of a vacuum window and in-beam ion detection for use in radiobiological experiments with 50 MeV particle beams

The vacuum window and in-beam ion detection of a radiobiological endstation have been studied using the Monte Carlo particle transport code MCNPX 2.5.0, investigating the effects of different elements on an incident beam of 50 MeV protons. The scattering and energy spread as well as secondary particle generation are analysed. A 200 nm thick silicon nitride vacuum window was found to have the least effect on the incident beam, giving an energy spread of 5.01(8)× 10−4 MeV. Placing a silicon pixel detector before the sample caused scattering of the beam of around 15 μm in radius; too much to be used for experiments targeting individual nuclei.