The effects of pre-etching time on the characteristic responses of electrochemically etched CR-39 neutron dosimeters

Abstract

Abstract The effects of pre-etching time (PET) or duration of etching of fast-neutron-induced-recoil tracks in CR-39 in 6N KOH at 60 °C on electrochemical etching neutron characteristic responses; i.e. sensitivity and mean recoil track diameter (MRTD) versus KOH normality up to 18N are investigated in this paper. Six sets of responses for PETs of 0, 1, 2, 3, 4, and 5 hours were obtained by using our new multi-chamber ECE (MCECE) system which reduced total operation time to about 6% of the time usually required when single-chamber ECE systems are used. The sensitivity response for zero PET showed a broad plateau and a high sensitivity low-LET peak around 16N. By increasing PET, another peak was also developed around 5N leading to “double-humped” responses with two maximums around 5N and 16N, and a minimum around 11N. On the other hand, the MRTD responses for all PETs studied showed the same general trend with maximums around 11N. In this paper, shape of tracks under different conditions are also investigated, new optimum conditions such as KOH concentrations of 5, 11, and 15N at 25 °C, with or without pre-etching, are recommended for tracks of lower-LET recoils including possibly protons, and alpha particle tracks over a broad energy range, and the efficiency of the MCECE system is also demonstrated.