Optimization of microwave-induced chemical etching for rapid development of neutron-induced recoil tracks in CR-39 detectors

• Microwave-induced chemical etching method is optimized for rapid development of recoil tracks due to neutrons in CR-39 detector.
• Several combinations of microwave powers and etching durations are investigated to standardize the suitable etching condition.
• Bulk-etch rates are determined for all microwave powers by two different methods, viz. gravimetric and removed thickness method.
• The method is found to be simple, effective and much faster compared to conventional chemical etching.

A systematic investigation is carried out to optimize the recently established microwave-induced chemical etching (MICE) parameters for rapid development of neutron-induced recoil tracks in CR-39 detectors. Several combinations of all available microwave powers with different etching durations were analysed to determine the most suitable etching condition. The etching duration was found to reduce with increasing microwave power and the tracks were observed at about 18, 15, 12, and 6 min for 300, 450, 600 and 900 W of microwave powers respectively compared to a few hours in chemical etching (CE) method. However, for complete development of tracks the etching duration of 30, 40, 50 and 60 min were found to be suitable for the microwave powers of 900, 600, 450 and 300 W, respectively. Temperature profiles of the etchant for all the available microwave powers at different etching durations were generated to regulate the etching process in a controlled manner. The bulk etch rates at different microwave powers were determined by 2 methods, viz., gravimetric and removed thickness methods. A logarithmic expression was used to fit the variation of bulk etch rate with microwave power. Neutron detection efficiencies were obtained for all the cases and the results on track parameters obtained with MICE technique were compared with those obtained from another detector processed with chemical etching.