Determination of a Critical Angle (θc) for Track Revelation for Different CR-39 Nuclear Track Detector Materials

Asaad H. Ismail

College of Science Education, Salahaddin University

Different thicknesses of 50 samples of commercially CR-39 Solid State Nuclear Track Detectors
(SSNTDs) have been prepared with different ages and from different produced companies. Track
parameters and plotting profiles, using computer program TRACK_TEST ware calculated. Detector
efficiency has been found to be depends strongly on the critical angle for track revelation (C). On the
other hand, critical angle depends strongly on the bulk etch rate.The results were specified that the
detectors older than 3 years seemed to show odd behaviors of VB with detector efficiency. For
age=3years the efficiency decreases exponentially for different alpha particle energy, and the bulk etch
rate (VB ) increases with decreasing age. This behavior may be important in applications of this detector;
for example, the calibration factor for radon measurements should be established by taking into account
the age of the detector

Keywords: CR-39 detectors, TRACK_TEST program, Critical angle and Detector efficiency

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