A comparison study of two phoswich detectors used for lung monitoring with varying thickness of primary crystal

In-vivo monitoring of actinides like ²³⁹Pu, ²⁴¹Am and natural uranium are carried out using Phoswich based lung monitoring system. The thickness of the primary detector used in Phoswich detector has to be optimized to get maximum efficiency with minimum background interference. Also the window material and its thickness as well as the inherent natural/fallout activity present in detector material has to be carefully looked into for better background reduction. Two phoswich detectors, of 3 mm thick and 15 mm thick primary NaI(Tl) crystals were compared for their performance using parameters such as efficiency, MDA, background interference etc and are discussed in this study. (author)