A Study of the Characteristics of Nuclear Track Detectors of types CR-39 and DAM-ADC for Nuclear Particles Registration

Abstract

Fast detection of alpha particles and fission fragments in CR-39 and DAM-ADC detectors was investigated using a new chemical etchant. The DAM-ADC is a new polymeric track detector made by the copolymerizing of Diallyl maleate (DAM) and allyldiglycol carbonate (ADC). 252Cf and 241Am sources were used for irradiating samples of CR-39 and DAM-ADC SSNTDs with fission fragments and alpha particles in air at normal temperature and pressure. A series of experimental chemical etching using NaOH and CH3OH were carried out at different temperature, the optimum etching condition for registration alpha particles and fission fragments in both CR-39 and DAM-ADC detectors were found. Suitable analyzing software has been used to analyze experimental data. From fission and alpha track diameters, the values of bulk etching rate (VB) is equal to 2.73 and 8.52μm/h for both detectors, respectively. Both of the sensitivity and etching efficiency was found to vary with the amount of Methanol in the etching solution. Pure NaOH was used as a control to compare with the result from etching in NaOH with different concentration of CH3OH. The etching efficiency is determined and compared with conventional aqueous solution of 6.25 N NaOH at 70 oC for etching time equal 5 hour. In this study, the obtained etching efficiency shows a considerable agreement with the previous work. For fast neutrons detection, samples of CR-39 and DAM-ADC SSNTDs irradiated at room temperature, by different effective doses of fast neutrons from a 5 mCi Am-Be source. Effective dose of the Am-Be source was measured by neutron monitorNM2 (Nuclear Enterprises). All samples were irradiated for constant time, 20h. At optimum etching condition (8 ml of 10N NaOH+ 1 ml CH3OH) at 60 oC; neutron induced tracks i.e. Proton, carbon and oxygen tracks, were register in CR-39detectors after 4 h and DAM-ADC detectors after 80 min. For radon gas concentration measurements, the calibration factor has been determined for CR-39 detector at different exposure time (day), it was found that the average value of calibration factor through 5days equal to 0.187 (track cm-2 d-1/Bqm-3) at 20 oC irradiation temperature.