The effect of two ultraviolet sources on the etching properties of a solid-state nuclear track detector CR-39

The effects of ultraviolet (UV)-laser at λ=266 nm and incoherent UV radiation at λ=254 nm on the properties of CR-39 were studied. The bulk etch rate of samples irradiated with UV-laser decreases with the progress of etching process and the decreasing was larger for pre-exposed (laser+alpha) samples than that of post-exposed (alpha+laser) samples. The decreasing in bulk etch rate indicates that cross-links were happened and subsequently hardening the detector surfaces. Therefore, CR-39 detector can be used in the measurement of heavy ions and high energetic particles without increasing the detector thickness. High bulk etch rate was noticed at the surface of the detectors irradiated with UV-laser. It was estimated to be 150 μm for post-exposed samples and 130 μm for pre-exposed sample. While in the case of incoherent UV radiation the bulk etch rate increases in the exposure period of time 1–2 and 7–8 h and was constant in the exposure period of time 2–7 h. For all samples the bulk etch rate was found to be equal in the exposure period 2–8 h. Several changes have been noticed on the surface of samples irradiated with both sources. Tracks of different sizes, shapes, high density and tracks overlap on each other.