Verification of the CR-39 detectors revelation methodology for radon 222 determination in indoor environments

The aim of this study was to verify the chemical attack revelation methodology of the CR 39 dosimeters described in the literature. For verification 27 dosimeters were first exposed in the CRCN NE calibration chamber (RN1 CRCN) at an activity of 5.00 kBq m^-3, with exposure time of 288 hours. Subsequently, groups of 9 dosimeters were separated by NaOH concentrations, one using 6.25M, one for 3M and finally 1M. Each group was subdivided with three dosimeters, the first subgroup using 40 ° C, the second 60 ° C and the third 90 ° C. In each subgroup CR 39 was removed after 1.5 hours, 3 hours and 5 hours. After development, the dosimeters were visualized under optical microscopy with 100% increase and the reading was performed with the aid of MATLAB® software, and 30 fields were read by dosimeters. As a result, it was seen that the reported revelation of the literature can visualize a higher density of traces, besides traces with larger diameters. The results enable the use of this methodology in the use of CR 39 dosimeters for the determination of radon 222 in indoor environment