METAL FILTERS FOR THE COMPENSATION OF PHOTON ENERGY-DEPENDENCE OF THE RESPONSE OF CASO4-DY - TEFLON TLD DISKS

Metal filters of aluminium, stainless steel, copper, cadmium, tin and lead were studied for compensation of the photon energy dependence of the response of CaSO4:Dy Teflon TLD Discs. It was found that metals such as cadmium and tin (which are normally used for this purpose) with their K absorption edges around 30 keV, are poor compensators of photon energy dependence. However, if either cadmium or tin is used in combination with either copper or stainless steel (with the lower Z filter nearer to the TLD dosimeter disc) a better compensation of photon energy dependence is achieved. Consequently, for personnel monitoring of X and gamma radiations, a TLD badge with CaSO4:Dy Teflon TLD discs and two sets of combination filters has been recommended. In the range of 27 keV-1.25 MeV this badge offers a photon energy response which varies within ±15%. This is a considerable improvement on the corresponding limits of ±65% on using a single filter. © 1979.