Development of a new thermoluminescent phosphor based on LiF:Mg,Ti (original) (raw)
Related papers
Thermoluminescence of LiF:Mg,Ti (TLD 100) Subject to 1.25 Mega Electron Volt Gamma Radiotherapy
National Academy Science Letters, 2015
Attempt has been made to investigate the thermoluminescence (TL) of LiF:Mg,Ti (TLD 100) chip irradiated with gamma energies of 1.25 MeV. The TL response increases over a wide photon dose range, from 1.0 to 10 Gy. The LiF:Mg,Ti demonstrates useful TL properties and represents as an excellent candidate for use in TL dosimetry of ionizing radiation. TLD 100 dosimeter has been found to yield a linear dose-TL signal relationship. Its linearity and sensitivity have been observed. The TL high sensitivity of TLD 100 makes it a very promising TL material for use in research and a variety of other applications.
1995
The dose response of the TL emission spectra of an LiF: Mg,Ti (TLD-100) sample and three LiF:Mg,Ti samples with different impurity concentrations (0~5 ppm Ti and 80-100 ppm Mg) have been measured. At a dose less than 22 Gy the emission spectrum of the TLD-100 sample comprises one emission band at 420 nm. The sample without Ti shows also one emission band but now at 620 nm. The spectra of the other two samples comprises two emission bands at 420 nm and 620 nm of which the intensity of the 420 nm band increases with increasing Ti concentration. The dose response of the glow peaks is different for peaks at different temperatures and emission bands. From these observations it can be concluded that in LiF: Mg,Ti at least some of the traps and luminescent centers are coupled.
Radiation Measurements, 2010
The high temperature thermoluminescence (HTTL) in the glow curve of LiF:Mg,Ti (TLD-100) is of continuing interest due to the dependence of the HTTL on ionization density. Following high ionization density irradiation, the intensity of the HTTL relative to peak 5 is much greater than the same ratio following low ionization density irradiation. Special attention has focused on the details of the linearity/supralinearity of the HTTL dose response at levels of dose between 10 and 500 mGy and whether the batch history (previous irradiation and annealing) affects the HTTL dose response? In this paper we demonstrate that batch identity leads to differences of w100% in the degree of the supralinearity of the dose response of peak 7 between two groups of TLD-100 chips. The results suggest that there may be significant non-universalities in the HTTL dose response and that further research is required to provide a sound basis for the use of the HTTL of TLD-100 in dosimetric applications.
Radiation damage and sensitization effects on thermoluminescence of LiF:Mg,Ti (TLD-700)
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2017
The radiation damage effects and enhancement the thermoluminescence (TL) efficiency of LiF:Mg,Ti (TLD-700)dosimeters via sensitization method were discussed. Attempts to eliminate the effects of damage and sensitization were made using different types of annealing processes. The results showed that after irradiating the dosimeters with dose > 250 Gy of 60 Co gamma source, damage effects were observed. The sensitivity of the total area under the curve was decreased by a factor of 0.5afterirradiationatapre−testdoseof2kGy.However,theeffectsofradiationdamageoneachglow−peakaredifferent.Theglow−peak2wastheonlypeakthatwasnotaffectedbythehigh−doseirradiation.Ithasbeenshownthatthedegreeoftheradiationdamageeffectisrelatedtothemaximumdose−responsefunction,fðDÞmaxoftheglow−peak.Ingeneral,significantradiationdamageeffectswereobservedfortheglow−peaksofhighfðDÞmax.Post−irradiationannealat280°Cfor30mincausesdramaticeffectsontheshapeoftheglowcurveandaswellasonthesensitivityofthedosimeters.Anincreasingbyafactorof0.5 after irradiation at a pre-test dose of 2 kGy. However, the effects of radiation damage on each glow-peak are different. The glow-peak 2 was the only peak that was not affected by the high-dose irradiation. It has been shown that the degree of the radiation damage effect is related to the maximum dose-response function, f ðDÞ max of the glow-peak. In general, significant radiation damage effects were observed for the glow-peaks of high f ðDÞ max. Post-irradiation anneal at 280°C for 30 min causes dramatic effects on the shape of the glowcurve and as well as on the sensitivity of the dosimeters. An increasing by a factor of 0.5afterirradiationatapre−testdoseof2kGy.However,theeffectsofradiationdamageoneachglow−peakaredifferent.Theglow−peak2wastheonlypeakthatwasnotaffectedbythehigh−doseirradiation.Ithasbeenshownthatthedegreeoftheradiationdamageeffectisrelatedtothemaximumdose−responsefunction,fðDÞmaxoftheglow−peak.Ingeneral,significantradiationdamageeffectswereobservedfortheglow−peaksofhighfðDÞmax.Post−irradiationannealat280°Cfor30mincausesdramaticeffectsontheshapeoftheglowcurveandaswellasonthesensitivityofthedosimeters.Anincreasingbyafactorof35 in the sensitivity of the total area under the curve was observed at a pre-test dose of 2 kGy. Improving the sensitivity of peak 7 by a factor of$22 was the dominant factor in increasing the sensitivity of the dosimeters. On the other hand, an increasing by factors of 2.5and2.5 and 2.5and4 was found for peaks 2 and 5 respectively. On the other hand, a decreasing by a factor $0.5 was observed for peaks 3 and 4. At pre-test dose levels >250 Gy, a very strange and high intensity tail was observed in the high-temperature region of the glow-curves. The readout anneal was not enough to remove this tail. While, the furnace anneal could eliminate the sensitization effects but not the radiation damage effects on the sensitivity of the dosimeters.
High-dose characterization of different LiF phosphors
Radiation Measurements, 2007
The dose response of three LiF TLDs: standard LiF:Mg,Ti (denoted MTS), high-sensitive LiF:Mg,Cu,P (MCP) and a recently developed in Kraków version of LiF:Mg,Ti with modified activator composition (MTT) and increased high-LET response was measured. The TLDs have been exposed to 60 Co gamma-rays, up to dose of 10 000 Gy, i.e. beyond saturation dose of the main dosimetric peaks, which corresponds to ca. 1000 Gy. The measured glow-curves were deconvolved into separate peaks with first order kinetic function (using self-developed GlowFit software). The dose response of the main peaks was found to be supralinear for MTS and sublinear for MCP detectors, as expected. The dose response of MTT was found to be even more supralinear than that of MTS. An interesting effect has been observed with regard to glow-curve shape of MCP detectors. Up to a dose of 1 kGy it remains practically unchanged, while for higher doses a strong growth of high-temperature peaks is observed. In the same dose region a decrease of the main peak of MCP with increasing dose is observed, unlike LiF:Mg,Ti detectors.
The role of f-centres in the thermoluminescence of LiF:Mg,Ti
International Journal of Radiation Applications and Instrumentation. Part D. Nuclear Tracks and Radiation Measurements, 1993
The aim of the present work was to investigate the relation of F-centres and TL peaks of differently doped LiF:Mg,Ti samples in a wide dose range. A direct experimental approach was applied: thermal bleaching of the 250 nm optical absorption (F-band) was measured during slow linear heating, and the TL emission intensity was simultaneously recorded. The results clearly indicate that although the F-centre absorption curve shows bleaching steps at almost every TL peak temperature, the sizes of the bleaching steps are far from being proportional to the corresponding TL peak intensities. This suggests that the role of the F-centres in the TL process is very different at the low and high temperature parts of the TL glow curve.