Extended dose response of 10B+CR-39 for thermal neutrons using spectrophotometric techniques

Abstract

In this work, measurements were carried out in a standard thermal neutron facility using CR-39 detector combined with boron converter to study the dose response of CR-39 for thermal neutrons and the implementation of spectrophotometric techniques to extend the response towards high dose equivalents. The dose dependent variations in the response of 10B+CR-39 detectors versus etching and track parameters, structural and optical parameters were studied by image analysis, FTIR and UV–Vis spectral analysis. The track density increased linearly with the thermal neutron dose equivalent up to 0.46 mSv with a sensitivity of 7.393 × 105 tracks cm−2 mSv−1, above which saturation effect was observed. The bulk etch rate increased with the dose equivalent up to 4.761 mSv, beyond which it was found to be saturated. From FTIR spectral analysis, the absorbance peak intensities decreased with the neutron dose equivalent up to 4.761 mSv and saturation effects were observed above it. Similar result was also obtained from the UV–Vis spectral analysis, thereby demonstrating its application for thermal neutron dosimetry up to 4.761 mSv. Accordingly, the empirical relations were derived for dose estimation up to 4.761 mSv. From the Tauc analysis, the optical band gap for both direct and indirect transactions decreased with the thermal neutron dose. This study can be useful in determining the thermal neutron dose equivalent in a simple and effective manner using a CR-39 track detector combined with boron converters, facilitating its potential application in neutron dosimetry extended up to 4.761 mSv.