TSEE MEASUREMENT OF THE DOSE OF ~(90)Sr-~990)Y BETA RADIATION BEHIND ABSORBERS OF DIFFERENT ATOMIC NUMBER

摘要

With the thermally stimulated exoelectron emission (TSEE) of BeO thin film detectors the dose in the beta radiation field of a ~(90)Sr-~(90)Y point source behind absorbers of different atomic number and thickness was determined. The absorbers consisted of either tissue-equivalent materials, aluminium, copper or gold. Their thickness ranged from 0 to 200 mg.cm~(-2). The TSEE detectors and absorbers were placed on a PMMA slab phantom at perpendicular radiation incidence. For Cu absorbers a Cu slab phantom was additionally used, for comparison. Increasing atomic number of the absorber causes stronger dose build- up behind an absorber thickness of 20-40 mg.cm~(-2) which can be attributed to the differences of mass scattering power.