Effective atomic numbers for photon energy absorption and energy dependence of some thermoluminescent dosimetric compounds

被引：34

作者：

Shivaramu ^{[1
]}

Ramprasath, V. ^{[1
]}

机构：

[1] Health and Safety Division, SHINE Grp., Indira Gandhi Ctr. A., Tamilnadu, India

来源：

Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | 2000年 / 168卷 / 03期

关键词：

Atomic physics - Dosimeters - Dosimetry - Electron energy levels - Photons - Radiotherapy - Thermoluminescence;

D O I：

10.1016/S0168-583X(99)01100-3

中图分类号：

学科分类号：

摘要：

Effective atomic numbers for photon energy absorption and energy dependence (ED) of some selected pure thermoluminescent dosimetric (TLD) compounds such as LiF, CaCO3, CaSO4, CaSO4&middot2H2O, CdSO4, SrSO4 and BaSO4 have been calculated in the energy region of 1 keV to 20 MeV. The more commonly used empirical formula for calculating the measure of ED in the energy region of interest in TL dosimeters through effective atomic numbers predicts higher values for all the materials studied compared to those ones calculated by direct method and by as much as 20% for SrSO4. A modified formula fitted to directly calculated effective atomic number data gives better agreement within a maximum deviation of ±3.94% for all the TLD materials studied. Overall the effective atomic number varies linearly with ED in the photon energy range of 1 keV to 20 MeV and thereby confirming the validity of a more commonly employed method of using the effective atomic number to calculate the measure of the ED in TL dosimetry. Significant differences exist between the effective atomic numbers for photon interaction and photon energy absorption in the energy region 20-150 keV for LiF, 2-300 keV region for CaCO3, CaSO4 and CaSO4&middot2H2O, 3-1000 keV region for CdSO4, 20-600 keV for SrSO4 and 1-1000 keV for BaSO4. The effect of absorption edge on effective atomic numbers and ED, their variation with photon energy and the possibility of defining two set values of these parameters below the K-absorption edge of high-Z element present in the TLD material are discussed.

引用

页码：294 / 304