A New Extremity System and Performance at INEL

Abstract

The TLD extremity dosimetry system described herein incorporates the components necessary for personnel extremity monitoring to meet current and proposed requirements. Single and dual element TLD dosemeters, ranging in thicknesses from 20 to 100 mg.cm -2 , and appropriate filtration comprise the extremity detectors which are uniquely identified by bar code labels. A dose algorithm used in conjunction with the dosemeters and TLD reader technology are capable of reporting shallow dose H p (0.07) from betas, low and high energy photons using any combination of these dosemeters. Performance tests and results were obtained by the Idaho National Engineering Laboratory (INEL) Operational Dosimetry Unit in the evaluation of a single extremity dosemeter capable of simultaneously monitoring beta and high energy gamma. Four TL materials and two filter types were tested in various combinations to 137 Cs photons, uranium slab, 90 Sr/ 90 Y, and 204 Tl beta, irradiations. An overview of the current INEL system dosemeter response, linearity, angular dependence, residual, and effects of physical damage to the dosemeter were tested. The results of these tests, presented here, lead to the preliminary conclusion that an extremity dosemeter can be constructed to monitor beta and high energy gamma radiation simultaneously.