Investigation of the ionisation density dependence of the glow curve characteristics of LIF:MG,TI (TLD-100)

Abstract

The dependence of the shape of the glow curve of LiF:Mg,Ti (TLD-100) on ionisation density was investigated using irradiation with (90)Sr/(90)Y beta rays, 60 and 250 kVp X rays, various heavy-charged particles and 0.2 and 14 MeV neutrons. Special attention is focused on the properties of high-temperature thermoluminescence; specifically, the behaviour of the high-temperature ratio (HTR) of Peaks 7 and 8 as a function of batch and annealing protocol. The correlation of Peaks 7 and 8 with average linear-energy-transfer (LET) is also investigated. The HTR of Peak 7 is found to be independent of LET for values of LET approximately >30 keV microm(-1). The behaviour of the HTR of Peak 8 with LET is observed to be erratic, which suggests that applications using the HTR should separate the contributions of Peaks 7 and 8 using computerised glow curve deconvolution. The behaviour of the HTR following neutron irradiation is complex and not fully understood. The shape of composite Peak 5 is observed to be broader following high ionisation alpha particle irradiation, suggesting that the combined use of the HTR and the shape of Peak 5 could lead to improved ionisation density discrimination for particles of high LET.

Delocalized recombination kinetic modelling of the LiF : Mg,Ti glow peak 5 thermoluminescence system

“…As shown in figure 3, the values of T max remain very nearly constant as a function of dose except for a slight increase in the temperature of maximum intensity of the HTTL. This, in fact, is observed in experimental measurements of the HTTL due to the greater relative intensity of peaks 8-10 at high dose level [40,41]. The reader should also note the increase in the concentration density of the CC at the temperatures corresponding to the thermal depletion of the TCs.…”

“…However, it deserves mention that the linear region of dose response observed for the HTTL at low dose levels extends over at most 1-2 decades of dose, whereas for peak 5, the dose response is linear over at least 5 decades of dose. In our recent studies [41] the dose response of peak 7 dose not deviate from linearity by more than ±20% (1 SD) over the dose range 10-200 mGy. However, if the dose response data for peaks 7 and 8 is fitted with a function of the form (top) and 1 • C s −1 (bottom).…”

50 Years of the Radiological Research Accelerator Facility (RARAF)

“…It has been in use essentially without modification since its initial construction and continues to be used frequently even today. In addition to cell cultures (16), the facility has been used to irradiate spores, thin layers of DNA in solution (17), 3D artificial tissue (18), TLDs (19), track etch dosimeters, and microchips. One result of irradiations using this facility was the measurement of oncogenic cell transformation as a function of LET (20, 21).…”

Study of thermally and optically stimulated luminescence in LiF:Mg,Ti following neutron and beta irradiation

“…The separate measurement of the beta and neutron dose components in both mixed neutron-beta and mixed gamma-neutron radiation fields remains a difficult issue [1][2][3]. The applied techniques usually employ two types of dosemeters in which the efficiency of the high ionization density (HID) radiation (heavy charged particles and neutrons) relative to that of the gammas and electrons of low ionization density (LID) is different [4][5][6][7][8][9][10][11]. In this work the LID irradiations were carried out with a 90 Sr/ 90 Y beta source (mean energy ~ 0.55 MeV) but the results are equally applicable to gamma radiation of the same range of energies.…”