Analysis of the isolated glow peak 6 in CaF2:Dy (TLD-200) following post-irradiation annealing at 145°C

The variable dose (VD), T m -T stop , initial rise, variable heating rate, peak shape and computerized glow curve deconvolution (CGCD) methods were used to determine the number of peaks, the order of kinetics (b), the activation energy (E a ) and attempt-to-escape frequency (s) associated with the dosimetric glow peak of α-Al 2 O 3 : C after β-irradiation at a dose level between 0.02 and 288 Gy. The E a -T stop and CGCD methods indicated that the dosimetric peak of this crystal is the superposition of at least two components (peak 2a and 2b). When the dose level reaches and exceeds saturation point, a third peak (peak 2c) is also evident on the low temperature side of the dosimetric peak. The VD and CGCD methods indicated that both components of the dosimetric peak have general-order kinetics that change with doses. The dose responses of peak 2a follow linear, supralinear, saturation and sublinear patterns, whereas peak 2b does not exhibit supralinear behaviour. They are saturated at different dose levels, peak 2a at D = 10 Gy and peak 2b at D = 5 Gy. E a -T stop plots obtained at two different dose levels (D = 10 and 1 Gy) indicated that the efficiency of thermal quenching effect on this sample is highly dependent on the dose level and decreases with increasing dose level, which also has pronounced effects on the evaluated kinetic and thermal quenching parameters of the dosimetric peak.

Section: Resultsmentioning

confidence: 99%

The analysis of dosimetric thermoluminescent glow peak of -Al₂O₃: C after different dose levels by -irradiation

Yazici

Solak

Öztürk

et al. 2002

“…A survey of the literature has indicated that very few studies on the thermoluminescence (TL) properties and defect structure of CaF 2 : Dy dosimeter have been carried out [6,7]. Especially, there have been only few systematic published studies [8][9][10][11], of kinetic parameters associated with the TL peaks in this material. Merz and Pershan [8,9] estimated the E a and s parameters for the major peaks appearing below 350 K, and Yazici and Öztürk [10,11] analysed the kinetic parameters of well-isolated glow peak 6 as a function of the duration of post-irradiation annealing at 145˚C.…”

Section: Introductionmentioning

confidence: 99%

The analysis of thermoluminescent glow peaks of CaF₂: Dy (TLD-200) after -irradiation

Yazici

Chen

Solak

et al. 2002

Variable dose (VD), T m-T stop , initial rise (IR), variable heating rate (VHR), peak shape (PS) and computerized glow curve deconvolution (CGCD) methods are used to determine the number of peaks, the order of kinetics (b), the activation energy (E a) and attempt-to-escape frequency (s) associated with the glow peaks in CaF 2 : Dy (TLD-200) after β-irradiation between the dose level 0.1 and 110 Gy. The T m-T stop procedure indicates that the glow curve of this crystal consists of at least nine glow peaks. The dose variation experiment indicates that seven of them, namely peaks 1-6 and 8, are of first-order kinetics and peaks 7 and 9 are of general-order kinetics. However, the T m-T stop procedure and the CGCD method have indicated that peak 6 has general-order kinetics too. The activation energy found with the IR, VHR, PS and CGCD methods for peak 4 yield very close values. For all other peaks, there is no agreement between the results of all the applied methods. This work also indicates that the post-irradiation annealing and the heating rate have pronounced effects on the evaluated kinetic parameters of all glow peaks.

“…Therefore, to minimize and standardize the thermal fading on the glow peaks below 100 ˚C, the time duration between irradiation and TL readout was always kept constant at about 1 min during these experiments. As seen in figure 1(a), the glow curve of this material consists of two groups of glow peaks both of which have several first-and/or general-order glow peaks [7,8]. They are well separated from each other and the first group, known as low temperature peaks, lies between room temperature and 230 ˚C and the second group, between 260 and 480 ˚C, are called the high temperature peaks.…”

Section: Resultsmentioning

confidence: 96%

“…A survey of the literature indicated that very few studies on the thermoluminescence properties and defect structures of CaF 2 : Dy dosimeter have been carried out [2][3][4][5][6][7][8]. Binder and Cameron [2] and Hasan and Charalambous [3] have studied its thermoluminescent dosimetric characteristics.…”

Section: Introductionmentioning

confidence: 99%

“…Binder and Cameron [2] and Hasan and Charalambous [3] have studied its thermoluminescent dosimetric characteristics. Recently, Yazici et al [7,8] have analysed these parameters for all glow peaks between room temperature and 500 ˚C, and they observed that the glow curve of this material has six peaks between room temperature and 230 ˚C and two peaks between 260 and 500 ˚C at a heating rate of 1 ˚C s −1 , but the shape of the glow curve of this material is highly influenced by the experimental parameters.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The influence of heating rate on the TL response of glow peaks of beta-irradiated CaF₂ : Dy (TLD-200)

Yazici¹

2005

In the current study, the influence of heating rates between 1 and 50 °C s−1 on the response of TL glow peaks of CaF2 : Dy (TLD-200) has been investigated using a computer glow curve deconvolution (CGCD) method before and after application of the thermal cleaning method at 90 and 170 °C. The trapping parameters of the main glow peaks were also obtained using the CGCD method as a function of heating rate. The results showed that the peak temperatures of all glow peaks increase with increasing heating rates. The peak height method showed that the peak value (Im) in the glow curve below 230 °C is approximately constant for low heating rates up to 10 °C s−1, but slightly increased after that by about 10% with increasing heating rate. The integrated total area of low temperature peaks below 230 °C is more stable. It remains constant for heating rates less than 25 °C s−1, then it slowly increases by about 10% with increasing heating rate up to 50 °C s−1. The increase in the total area of low temperature peaks is reduced after the application of the thermal cleaning method. The peak intensities and total area of high temperature peaks above 260 °C decrease continuously with increasing heating rate in the investigated region of heating rates.