Design of simulated-gas calibration source and self-attenuation correction methods for radioactive noble gas measurement with HPGe detector

In this study, to achieve accurate measurement of radioactive noble gas and enhance the precision of efficiency calibration, a relatively low-cost and low-density simulated-gas calibration source (SGCS) was produced from polyurethane foam with a density of rho = 0.098 g cm(-3). Using SGCS with a Marinelli beaker geometry, the efficiency calibration was applied to a BE5030, 50.5% relative efficiency HPGe detector in an energy range of 59.54 keV similar to 1836.06 keV. Then, taking the 81 keV gamma-ray emitted by Xe-133 as an example, due to the density difference between the SGCS and the Xe-133 gas sample, it is necessary to correct for self-attenuation effects. Therefore, a semi-empirical function for self-attenuation correction was established by using LabSOCS software and XCOM. Upon validation, the relative deviation of efficiency calibration values between the SGCS and the LabSOCS of Xe-133 under the density of 0.001 g cm(-3) to 0.01 g cm(-3) was about 3%. After using the self-attenuation correction method established in this study, the results verified a good consistency of the efficiency calculated by SGCS and LabSOCS software.