Bremsstrahlung from a shielded beta irradiator

Abstract

A beta irradiation unit is described which contains a 4 GBq90Sr source. The shielding, comprising perspex, aluminium and lead is designed to provide an acceptably low doserate to the user without exceeding a manageable mass as it is necessary to move the shielded source while in use for thermoluminescence dating. The cylindrical shield is 192 mm in diameter and 192 mm high and has a mass of 33 kg. Measurmeents of bremsstrahlung spectra from the system are reported and interesting features noted. A comparison of the bremsstrahlung dose-rates as determined by three different portable dose-rate monitors is also presented.