Preliminary thermoluminescence investigation of commercial pharmaceutical glass containers towards the sterilization dosimetry of liquid drugs

INITIAL TL/OSL/EPR CONSIDERATIONS FOR COMMERCIAL DIATOMACEOUS EARTH IN RETROSPECTIVE DOSIMETRY AND DATING

Diatomaceous earth is found in various locations around the planet. It is caused by the deposited exoskeleton material formed by the death of large concentrated populations of diatoms. The exoskeleton is effectively pure silicate and as such becomes a prospective material for retrospective dosimetry and dating. This work investigated the thermoluminescence (TL) and optically stimulated luminescence properties of commercially obtained diatomaceous earth. The material was not found to have useful dosimetric properties with conventional TL methodologies but did provide large dose estimates using the Single Aliquot Regeneration technique on some subset samples. These findings for organic silicate did suggest some mechanisms explaining the sensitization process in geological silicate materials utilized in dosimetry and dating. Electron paramagnetic resonance was identified as a potential future method for evaluating this material as it revealed unique signal components not found in igneous or commercially produced silicates.

Effect of γ-irradiation on thermal and thermoluminescence properties of polystyrene/europium (III) oxide composite film

In the present study, polystyrene:europium (III) oxide polymer films at a ratio of 95:5 wt% were prepared using a solution casting technique. These polymeric films were irradiated with 5, 25 and 50 kGy γ-radiation doses and their thermoluminescence (TL) and thermal properties were studied as a function of radiation dose. Analysis of Fourier transform infrared spectra revealed different modes of vibration and polymer-filler interaction. Reduction of vibrational modes with radiation dose was observed. The TL glow curve intensity was observed to increase with increasing radiation dose and to become broader in the 378 K and 444 K regions. Detrapping of electrons implied by the glow curve was caused by thermally induced macromolecular motion, concurrent with β-relaxation in polystyrene. The TL glow curve parameters were computed using a glow curve deconvolution method. Differential scanning calorimetry analysis indicated that the glass transition temperature (T_g ) increased with increase in dose, suggesting crosslinking of the polymer chain. Scanning electron microscopy analysis evidenced the change in surface morphology due to γ-irradiation.