Thermal lens spectroscopy dosimetry at high doses using a commercial transparent glass

A dual-beam mode-mismatched configuration of the thermal lens spectroscopy technique was applied to characterize commercial transparent glass irradiated with high doses of beta radiation (Sr-90 + Y-90). Thermo-optical properties of the glass were studied after irradiation within an approximate dose range of 1.10(3)-7.10(3) Gy. The glass family and structural group type as well as its amorphous nature were confirmed by Raman spectroscopy and X-ray diffraction. The spectral absorption in UV-Vis range of the samples revealed changes due to radiation exposure. The parameters of thermal diffusivity and phase difference were investigated as a function of the radiation doses, using a CW diode laser (488 nm and 40.0 mW) for excitation and a He-Ne laser (632.8 nm) as a probe beam. The theta phase difference and the steady-state thermal lens signal presented a linear response in the dose range studied. Thermal lens spectroscopy was found to be a relatively good candidate as a dosimetry technique that can be useful for investigation of dosimetry characteristics in new glasses.