PERSONNEL NEUTRON DOSIMETRY USING HOT, LOW-FREQUENCY ELECTROCHEMICAL ETCHING.

We have developed an electrochemical-etch procedure for the processing of large numbers of CR-39 dosimeters. Specially designed Homann-Type chambers can etch up to 24 CR-39 chips, or foils, at one time. In our two-step procedure, the second step, called blow-up, increases the tracks' size and makes them relatively uniform. The energy response is fairly flat from approximately 150 kev to 4. 5 Mev, but drops by about a factor of three in the 13-16 Mev range. The sensitivity of the dosimetry system is 6 tracks/mrem with a background of 8 mrem, giving a lower limit of sensitivity of approximately 10 mrem for the dosimeter (when three foils are used). Because greater numbers of CR-39 foils can be accommodated at any one time, our procedure is quite efficient for operations with large numbers of dosimeters to be processed.