Determination of optimum etching duration of CR-39 track detector for high fluence alpha particle measurement using UV-Vis spectroscopy

The UV-Vis spectroscopy has been found suitable for fluence measurement with CR-39 track detector when the track counting with optical microscope is difficult due to huge overlapping of tracks. In this work, the optimum etching duration has been determined for alpha particle measurement using CR-39 as detector and UV-Vis spectroscopy as characterisation technique. For this purpose, CR-39 detectors were irradiated to alpha particles with known fluence followed by stepwise chemical etching. The track images were captured as well as UV-Vis spectra were recorded after etching. The transmission values in the UV-Vis spectra were found to be decreasing with etching time and fluence. The optical absorbance at a particular wavelength, i.e., 600 nm was found to increase with the fluence. The saturation effect was observed at higher fluence when the etching time was above 4 h. The optimum etching time was determined to be 4 h based on the linear response in wide fluence range from 8.56 x 10(4) to 1.93 x 10(7) cm(-2). Linear relation for the absorbance (at 600 nm) and fluence was derived which can be used as multiplication factor to estimate the fluence in the range of 8.56 x 10(4)-1.93 x 10(7) cm(-2), after performing 4 h etching.