Monte-Carlo simulations of an AmBe neutron source

The Department of Physics and Astronomy in Uppsala is planning to construct a source-based neutron irradiation facility at Ångströms laboratory. The purpose of this facility will, as of now, mainly be for students and employees to conduct scientific experiments and to calibrate the university's neutron scintillator detectors. A vital part of the construction is the shielding of the source, for both safety reasons and practicality issues. In this project, a series of simulations were made to determine the necessary dimensions of the shielding to ensure that the radiation dose levels stayed under the stipulated 6 mSv per year. Two types of shielding materials were tested, borated and non-borated polyethylene. It was found that the borated polyethylene performed better in shielding the source, but not enough to justify the higher material cost. The optimal dimensions of the shielding for non-borated polyethylene were found to be 60x60x74cm