| Popis: |
Since the results of the measurement of the X-ray-excited radioluminescence as a function of temperature (Part I of this paper) of TL dosimetry materials were difficult to interpret in terms of quenching of thermoluminescence, the direct measurement was made of the TL light sum and the glow-peak height as a function of heating rate. In order to overcome the problem of thermal lag between the heating planchet and the phosphor, a method was developed to achieve a high degree of thermal coupling by mixing powdered phosphor and gold and pressing the mixture to the surface of a gold disk. The glow curves from these gold plaques were recorded with a reader that produced heating programs which were linear to a few percent from rates of 4°C/min up to 640°C/min. By this technique glow-peak heights and light sums were measured for CaF2:Mn, natural fluorite, LiF(TLD-100), CaSO4:Mn, Li2B4O7:Mn, and terbium-activated lithium aluminosilicate glass over the full range of heating rates. Considerable variability was found in the thermal quenching characteristics of the various phosphors. All but the fluorite and the Li2B4O7:Mn showed some decrease in light output at high heating rates. LiF exhibited a decrease for low heating rates as well, with a broad maximum in the light output at about 100°C/min. |
