Pages: 37-46

Authors: Van-Toan Phan, Van-Hung Nguyen, Hung-Thai Pham, Van-Dung Pham, Dinh-Khoa Tran, and Hoai-Nam Tran

Abstract

This paper presents the thermoluminescence properties of K₂GdF₅:Tb material irradiated in a reference neutron-gamma field and its possibility to be used in neutron dosimetry. Double fluoride of K₂GdF₅ doped with 10 at% Tb³⁺ ions was synthesized under solid-state reaction conditions and irradiated in the reference neutron-gamma field of ²⁴¹Am-Be source. The thermoluminescence glow curves were measured by the Rexon UL-320 TLD reader connected with the WinRex-320 processing program for obtaining the integrated thermoluminescence signals (counts). The results show that the temperature peaks of the irradiated K₂GdF₅:Tb material concerning the gamma and neutron fields at the distance of 100 cm from the source are at 230 °C and 300 °C, respectively. The sensitivity ratios of fast-to-thermal neutron and gamma-to-thermal neutron are 6.3 % and 18.2 %, respectively. The batch homogeneity and reproducibility are less than 30 % and 7.5 %, respectively. The linearity is less than 10 % in the dose range of less than 24 mSv. The detection threshold is less than 0.1 mSv, and the fading is 10.7 % after 90 days of irradiation. These thermoluminescence properties of K₂GdF₅:Tb material considerably satisfy the requirements to be used in neutron dosimetry.

Key words: thermoluminescence properties, K₂GdF₅:Tb material, neutron and gamma irradiation

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