High-dose high-temperature emission of LiF:Mg,Cu,P: Thermally and radiation induced loss & recovery of its sensitivity

Abstract

HIGHLIGHTS:• High-dose high-temperature TL emission is present in LiF:Mg,Cu,P' glowcurves.• LiF:Mg,Cu,P can measure doses ranging from below 1 μGy to about 1 MGy.• Thermally-induced sensitivity loss of the samples can be recovered.• Sensitivity damage of the samples after high-dose measurements is Fuldy reversible.• High-dose measurements changes to the structure of the material are reversible. AbstractHighly sensitive LiF:Mg,Cu,P (MCP) detectors enable measurements of radiation doses from tens of nanograys up to a few kilograys, where the saturation of the signal of the main dosimetric peak occurs. Thanks to the recently observed high-dose high-temperature emission of MCP detectors heated to temperatures up to 600°C after exposures to radiation doses ranging from 1 kGy to 1 MGy, a new method of TL measurement of radiation doses has been recently developed at the Institute of Nuclear Physics (IFJ). This method can measure doses ranging from micrograys up to a megagray. So far, high dose measurements were performed on fresh MCP samples and each detector was used only once, because as a result of these measurements, the detectors lose their sensitivity to a large extent. In this study, a specific thermal treatment intended to fully restore the loss of MCPs TL sensitivity was sought. We have investigated several annealing procedures, applying different temperatures (from 400°C up to 700°C) for different periods of time (10-30 minutes) in argon atmosphere. In this way we were able to recover MCP sensitivity fully, allowing for reuse of the samples after high-dose irradiation and high-temperature measurement.

On LiF:Mg,Cu,P and LiF:Mg,Ti phosphors high & ultra-high dose features

“…Oster et al, 1993;Tang et al, 2000), hence following high-dose high-temperature measurements this is entangled with radiation-induced sensitivity loss. These effects were thoroughly studied very recently and it had been proven that thermally and radiation-induced sensitivity loss of LiF:Mg,Cu,P is fully reversible up to predose of 100 kGy, using high-temperature annealing procedure developed by Obryk et al (2013), which takes less than an hour. This indicates that high temperature and high doses of radiation do not cause irreversible changes in the MCP material.…”

“…Fig.2. LiF:Mg,Cu,P glow-curves resulting from gamma irradiation ( 60 Co source at KAERI) for the dose range 1 kGy-500 kGy(Obryk et al, 2013).…”

Thermoluminescence Studies of High Energy X‐Rays Irradiated Dy3+ Doped Mg0.65Zn0.3Al2O4:0.05Dy Nanophosphor

“…The key characteristics considered in this study include dose-response range of the material and its fading properties. [11] In this study, we describe the thermoluminescence characteristics of Mg 0.65 Zn 0.3 Al 2 O 4 :0.05Dy nanophosphors exposed to X-rays to assess their suitability for high radiation TL dosimetry. Mg 0.65 Zn 0.3 Al 2 O 4 :0.05Dy nanophosphor was prepared using a modified solution combustion synthesis technique with the objective of its application in the high dose range.…”

High-Sensitivity and Wide-Linear-Range Thermoluminescence Dosimeter LiMgPO4:Tm,Tb,B for Detecting High-Dose Radiation

“…14,15 Obryk's group reported in 2007 that LiF:Mg,Cu,P can measure up to 1 MGy dose; 16 however, it could be used only for one-off measurement because of its sensitivity loss resulting from highdose radiation and high-temperature reading. 15 Although its sensitivity can be partially recovered through a specific annealing procedure in argon atmosphere, 17 it is costly and time-consuming. Therefore, it is urgent to develop a reusable TLD with high sensitivity and wide linear range for high-dose detecting.…”

“…A thermoluminescence dosimeter (TLD) has been successfully used to monitor personal and environmental doses for a long time, benefiting from its reusability, reliability, sensitivity, and speediness of readout. − However, it is still not fully competent to the task of high-dose detecting as with the chemical or electron paramagnetic resonance dosimeter, because TLD easily reaches saturation at a relatively low dose, such as ∼20–1000 Gy for commercial LiF:Mg,Cu,P. , Obryk’s group reported in 2007 that LiF:Mg,Cu,P can measure up to 1 MGy dose; however, it could be used only for one-off measurement because of its sensitivity loss resulting from high-dose radiation and high-temperature reading . Although its sensitivity can be partially recovered through a specific annealing procedure in argon atmosphere, it is costly and time-consuming. Therefore, it is urgent to develop a reusable TLD with high sensitivity and wide linear range for high-dose detecting.…”