LIGHT CONVERSION EFFICIENCY OF ALUMINUM-OXIDE DOSIMETERS IRRADIATED WITH (241)AM ALPHA-PARTICLES

Highly sensitive, anion defect, monocrystalline alpha-Al2O3:C thermolu minescence dosemeters were exposed to alpha particles from a 246 Bq Am -241 source. The energy of the alpha particles was degraded by Mylar f oils of different thicknesses. The alpha particles were completely sto pped in the 1 mm thick dosemeter chip. Their energy distributions were measured with a silicon surface barrier detector and stored in a mult ichannel analyser interfaced to a computer. The mean energy of the alp ha particles after passing through the Mylar foils was calculated usin g the Bethe-Bloch stopping power formula. The light conversion efficie ncies relative to Cs-137 gamma rays are shown as a function of peak al pha energy in the dosemeter. The self-attenuation of thermoluminescenc e signal in the dosemeter was determined experimentally.