PERFORMANCE OF ALPHA-PARTICLE SPECTROSCOPY USING A TASTRAK(TM) DETECTOR

Alpha particle spectroscopy by automated analysis of etched alpha part icle tracks in TASTRAK(TM) (CR-39) type plastic is described. The meth od is based on the measurement of two geometric parameters of etched t racks, the minor axis (m), and the diameter of the etched out track en d (d). Accurate measurement of these two parameters allows reliable se paration of tracks according to alpha particle energy, with a FWHM of 105-130 keV, or 1.5-2.5%, in an energy band of 1.5 MeV. Pre-etching th e plastic at 98 degrees C before exposure to the alpha particle source caused a decrease in V-T/V-B, resulting in an improved energy resolut ion of 80-110 keV (1.33-2%), with a concomitant decrease in the energy band to 1.2 MeV. Within this band, the intrinsic measurement efficien cy is as high as 0.75, a critical factor for possible low level measur ement applications. The results indicate that a basis exists for a rob ust working method for alpha particle spectroscopy in TASTRAK(TM) plas tic.