Energy dependence of new thermoluminescent detectors in terms of HP(10) values.

The aim of this work was to determine energy dependence characteristics in terms of values of the personal dose equivalent, HP(10). The following types of thermoluminescent detectors (TLDs) were investigated: (a) two new types based on lithium borate, Li2B4O7:Cu,In and Li2B4O7:Cu,In,Ag; (b) two types based on the highly sensitive material LiF:Mg,Cu,P, TLD-700H and GR 200A; (c) two well-known types of LiF:Mg,Ti detector, TLD-100 and TLD-700 and (d) highly sensitive Al2O3:C detectors. TLDs previously calibrated with 137Cs gamma rays were simultaneously irradiated with X ray beams in the range of mean energies between 33 and 116 keV. The irradiations were performed with detectors in polymethyl methacrylate (PMMA) holders placed on a 30 cm x 30 cm x 15 cm water phantom with PMMA walls (ISO phantom). Measured energy responses were compared with calculated data for HP(10) values. The results confirmed the satisfactory tissue equivalent characteristics of all investigated TLDs except Al2O3:C, which (due to its large energy dependence) is suitable for personal dosimetry only with an appropriate filter.