Thermoluminescence characteristics of teflon embedded CaSO₄:Dy TLD

The Korea Atomic Energy Research Institute (KAERI) is manufacturing CaSO₄:Dy Teflon TL pellets which have more sensitivity and stability than commercial TLD. A method is presented of preparing the CaSO₄:Dy phosphor-embedded Teflon powder, which is then compressed to a thin pellet form used as the TLD element. Investigations are made to determine optimum preparation conditions and dosimetric characteristics of the CaSO₄:Dy Teflon pellet such as the sensitivity, energy response, dose response, fading, re-usability, and lowest level of detection. The results show that the sensitivity of the CaSO₄:Dy pellet is 2 times higher than that of the commercial Teledyne CaSO₄:Dy pellet. A dose-response was observed to be linear in the range from 10^-5 to 10 Gy. The relative energy response in the low energy region was 9.6 (normalised to the ¹³⁷Cs gamma source), and the fading rate was about 10% for five months. The re-usability was estimated to be more than 60 cycles, and the low level of detection dose was 22 μGy. From the results, the CaSO₄:Dy pellet developed in KAERI can be successfully used in personal dosemeters through appropriate filter design for compensating the energy response.