In this work, nuclear track detectors (NTDs) of CR-39 and LR-115 were used in identification of charged particles and determination of doses of fast and thermal neutrons. CR-39 characterizations were carried out using etchant conditions of 6N NaOH at 60°C with V_B ≈ 0.9 μm/hr with registration efficiency better than 90 % and critical angle of etching under different removal layer values. In addition, CR-39 NTDs were used in fast neutron registration utilizing their interactions with the constituent atoms of the detector material. Induced-proton track densities (ρT) were registered at different etching times and neutron doses (Dfn) from 1.54 up to ≈ 44 mSv. An exponential relationship between (ρT) and Dfn was found to obey the formula Dfn = 1.27 exp(0.067 ρT). An empirical formula to relate the induced proton energy (E_p) with its (dE/dx)_p in CR-39 was found to be E_p=170.031 (dE/dx)_p^-1.518 MeV/μm. Also, in this work, CR-39 and LR-115 track detectors were used for detection of dose of thermal neutrons obtained through the polymethyle methacrylate sheet (PMMA) moderation of ²⁴¹Am-Be fast neutrons source with B₂O ₃ converter. CR-39 and LR-115 NTDs were exposed to thermal neutrons for up to 37 hrs. Four sets of detectors were irradiated at exposure times of 1.5, 18, 21 and 37 hrs. The thermal neutron fluxes were calculated from the induced-ions track density through the concepts of the efficiency factor from the total track density (r _T). The equivalent doses (D) of thermal neutrons were deduced using the dose-flux relationship or flux-dose conversion factor. Moreover, ⁷Li (0.84 MeV) and ⁴₂He (1.47 MeV) induced-ion tracks were produced from the interaction of thermal neutrons with boron-covered CR-39 detector. The discrimination between alpha panicles ( ⁴₂He -ions) and ⁷Li-ions was carried out extensively. Data measurements were repeated many times in order to achieve better accuracy. This discrimination (or spectroscopic analysis) is based on an adequate and careful analysis of the acquired data obtained from the circular track diameters induced in CR-39 detectors as a result of thermal-neutron-boron interaction mechanisms. The charged particles (⁴He, ⁷Li) identifications were successfully obtained using circular-track diameter analysis method with alpha tracks from ²⁴¹Am alpha reference source. Although such method is tedious, results are indeed encouraging and certainly recommended. Results of this study are then discussed within the frame work of track formation theories and etching mechanism in NTDs.

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