The impact of the broad range of gamma doses on follow-up fission fragment track parameters in CR-39 radiation detector.

In this study, the effect of high γ-doses on the track parameters, structure as well as optical properties of pristine and γ-irradiation CR-39 nuclear track detector (NTD) were investigated. CR-39 detectors were exposed to γ-doses from 50 up to 500 kGy and then irradiated by fission ions (F.F) of fluence from ²⁵² CF source. The track diameter (D), bulk etch rate (V _B ), etch induction time (EIT), cut-off or saturated time (t _cut-off ) for saturated diameters and projected track length (L _o ) of normally and inclined incident fission tracks were estimated for different removal layers (h). A linear relationship between D and γ-doses (D _γ ) up to 500 k Gy was obtained. The V _B for pristine and for γ-irradiated CR-39 was determined. A linear behaviour of V _B was obtained up to 300 kGy. Etch induction time (EIT) and saturated time (t _cut-off ) of pristine and γ-irradiated detectors for normal and inclined fission ions tracks were evaluated respectively up to 500 kGy. Each EIT and t _cut-off decreased exponentially fast with increasing γ-doses but the inclined incidence appeared earlier than normal case. Pristine and γ-irradiated CR-39 detectors were examined using FTIR and UV-Vis spectrophotometer. From this study, a linear relation of band gap energies (E _gap ) as a function of γ-doses, Dγ, was obtained. The value of (E _gap ) decreased when increasing γ-doses for direct and indirect transitions, respectively. In addition, a systematic increase of Urbach energy (E _U ) was recorded together with the D _γ increase. Moreover, a linear behavior of the refractive index (n) along with γ-irradiated CR-39 plastic detector was observed via direct and indirect methods.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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