Detection Response Evaluation of a Solid State Nuclear Track Detector Durolon®

In a radioactive decay process of the $^{222}$Rn, in accordance with the Poisson distribution, the emitted $\alpha$ particle probability reaching a particular point in the active area of the solid state nuclear track detector (SSNTD) is equal to any other particle emitted reaching any point of any area of this detector. Considering the fact that the probability is equal to any part of the area and that there are no external influences, it is reasonable to say that the quantity of incident particles expected per area is equal and corresponding. This characteristic allows these films may be applied as SSNTD detectors. It is assumed so as essential characteristic for SSNTD detectors that regularity in the observed counting frequency of the incident particles should match the expected frequency for counting. The aim of this work is an evaluation of response of count for the SSNTD detector in relation of the total count per area of incident $\alpha$ particles by applying the $\chi^{2}$ test at a 5$\%$ level of statistical significance hoping that the expected and observed frequencies are equivalent (null hypothesis). To demonstrate this proposition, samples of 1cm? of Durolon$^{\tiny{\textregistered}}$ (Bisphenol-A, used as SSNTD) packed in a dosimeter type NRPB/SSI-H were irradiated in a calibrated source PYLON RN-1023 with a activity of 21kBq/$m^{3}$ and revealed using a standard chemical attack protocol PEW-40 with subsequent track counting using a conventional microscope with magnification of 40x. In the process data acquisition it was discarded lateral area of the SSNTD and randomly selected 10 areas (770x1028$\mu$m) along the central part of the detector. For each region was made the total count of the tracks. Based on the tracks counts, the average and the standard deviation was determined and a relative error. Considering the average value as an expected value, was applied the $\chi^{2}$ test considering the partial counting as a observed values. The average of counts is 63$\pm$4 tracks/area, with a relative error of 7$\%$, the determined $\chi^{2}$ value was 2.38 and the tabulated value considering 5$\%$ of statistical significance was 3.33. As $\chi^{2}_{9,0.05} >$ $\chi^{2}_{calculated}$, the null hypothesis is accepted. In conclusion, the results show that the null hypothesis is accepted and the tracks counting in partial areas they are corresponding to a level of statistical significance of 5$\%$. The detection response for this SSNTD can be considered as valid.