Structural and optical characterization of alpha-irradiated and chemically etched PM-355 solid state nuclear track detectors before and after solar exposure.

PM-355 polymeric solid state nuclear track detectors were studied. Samples were irradiated with alpha particles before and after exposure to sunlight under various seasonal conditions. Track formation and optical characteristics of chemically etched samples were investigated. X-ray diffraction (XRD) analysis showed that the dominant structure of the PM-355 detectors is of an amorphous nature with some degree of crystallinity. Micro strain, distortion density and distortion parameter were calculated from the XRD data, and indicate that the structure was modified after alpha irradiation and solar exposure. There was a tendency in the structure towards crystallinity. Some optical properties of PM-355 detectors were studied using Ultraviolet-Visible absorption spectroscopy. The absorption edge was detectable in all samples. The direct band gap decreased first and then subsequently increased again. The fluorescence spectra of alpha irradiated and solar exposed PM-355 polymer detectors after chemical etching showed three dominant peaks at wavelengths 327, 418 and 465 nm, respectively. The changes in the optical properties can be used to detect the effect of alpha and ultraviolet irradiations. The variation of the optical band gap, fluorescence spectra and/or track diameters can be used as a detection of nuclear radiation.