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Phototransferred thermoluminescence of annealed synthetic quartz: Analysis of illumination-time profiles, kinetics and competition effects
摘要： Phototransferred thermoluminescence (PTTL) induced from annealed synthetic quartz using 470 nm blue light is reported. The quartz was annealed at 900oC for 10, 30 and 60 minutes prior to use. A glow curve of conventional TL measured at 1oC s-1 following irradiation to 200 Gy for the sample annealed for 10 minutes shows six peaks at 90, 122, 176, 210, 240 and 340oC. The sample annealed for 30 minutes has peaks at 80, 110, 136, 196, 240 and 330oC. Similarly, the sample annealed for 60 minutes also has six peaks at 80, 120, 134, 188, 235 and 340oC. For ease of reference, these are labelled I-VI respectively. Peaks observed under PTTL are referred to as A1 onwards. Of the six peaks, only the first three are reproduced under phototransfer for the sample annealed for 60 minutes. When the duration of annealing was reduced to 10 minutes, PTTL is induced only at peaks A1 and A3. Interestingly, for the intermediate duration of annealing of 30 minutes, the only peak that appears under phototransfer is the first one, A1. For quartz annealed for 10 minutes, the PTTL appears as long as the preheating temperature does not exceed 560oC. On the other hand, in the quartz annealed for 30 and 60 minutes, PTTL only appears for preheating to and below 450oC. This shows that the occupancy of deep electron traps at temperatures beyond 450 or 560oC is low in the said samples. The activation energy for peaks A1 and A3 was found to be about 0.68 eV. The PTTL peaks were studied for thermal quenching and peaks A1 and A3 were determined to be subject to this effect. The activation energy for thermal quenching was determined as 0.62 ± 0.04 eV in analysis using peak A1. In all cases, the PTTL intensity goes through a peak as a function of illumination time. The experimental dependence of PTTL intensity on illumination time is modelled using sets of coupled linear differential equations based on systems of donors and acceptors whose number is determined by preheating temperature. Competition effects involved in the PTTL have been discussed.
关键词： competition effects,phototransferred thermoluminescence,synthetic quartz,Annealing,thermal quenching
更新于2025-09-12 10:27:22
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Phototransferred thermoluminescence from natural quartz annealed at 1000?°C: Analysis of time-dependent evolution of intensity and competition effects
摘要： Phototransferred thermoluminescence (PTTL) related to multiple acceptors and donors in natural quartz is reported. A glow curve measured at 1 °C s?1 after beta irradiation to 300 Gy has four peaks labelled I, II, III, and IV at 70, 124, 170, and 298 °C respectively. Preparatory to measurement of PTTL, these peaks were removed in turn by preheating to 100, 140, 250 and 500 °C. PTTL is observed for peak I after any of these preheating temperatures. This means that peak I is reproduced, under phototransfer, when any of peak I, II, III or IV has been removed. Peak II is only reproduced after preheating to 250 °C to remove peaks I, II and III. Peak II does not re-appear after any preheating beyond 250 °C. Peak III re-appears under phototransfer following preheating to either 250 or 500 °C. No PTTL was observed for peak IV at all. The behaviour of peaks II and IV are suggestive of competition effects that merit investigation. This is addressed in this report. The dependence of PTTL intensity on the duration of illumination is studied for all PTTL peaks corresponding to various preheating temperatures. Peak I shows an initial increase in intensity followed by a decrease with illumination for preheating to 100, 140 and 500 °C. However when the sample is preheated to 250 °C, the intensity decreases monotonically. The PTTL intensity for peaks II and III go through a slow and extended growth up to 1500 s before the onset of any decrease. The change of intensity with illumination time is modelled using coupled first-order linear differential equations on the basis of systems of acceptors and donors whose number depends on the preheating temperature.
关键词： Models,Donors,Acceptors,Competition effects,Phototransferred thermoluminescence,Natural quartz
更新于2025-09-12 10:27:22