- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
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
-
AIP Conference Proceedings [AIP Publishing PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019 - Kerala, India (12–14 June 2019)] PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON ADVANCED MATERIALS: ICAM 2019 - Synthesis and characterization of GO coupled SrS material with a study of luminescence properties
摘要： In recent times the production of Graphene Oxide (GO) nanoparticles has drawn an enormous attention of the scientists because of its wide applications and potential candidature in the band gap engineering. Keeping the above facts in mind, the authors have prepared GO with modified Hummer’s method and then prepared a coupled product using annealing and cold freezing method with a phosphorescent material (Strontium Sulfide). The synthesis of GO was confirmed using XRD and Raman techniques. The luminescence properties of pure GO and the coupled product were studied with the help of Thermoluminescence glow curves. The glow curves clearly suggest the formation of trapping centres in the forbidden energy gap, in both the samples with interesting and substantial changes in trapping centres in case of coupled product as compared to pure GO sample. The results can directly be applied for the preparation of new optical materials.
关键词： Strontium Sulfide,optical materials,luminescence properties,thermoluminescence,Graphene Oxide
更新于2025-09-11 14:15:04
-
Photostimulated and persistent luminescence of samarium ions in BaFCl
摘要： Storage phosphors with e?cient photostimulated luminescence (PSL) and/or persistent luminescence (PersL) are in great demand for a range of applications. In this paper, PSL, PersL and thermoluminescence (TL) of samarium ions doped in a macroscopic and sub-micron crystals of BaFCl are reported, and it is demonstrated that the co-precipitated BaFCl:Sm3+ sub-micron crystals become an e?cient photostimulable X-ray storage phosphor upon annealing in the temperature range of 200–500 °C. The dependence of storage phosphor properties on annealing temperature was investigated and it was found that the X-irradiated co-precipitated BaFCl:Sm3+ crystallites (~400 nm size) showed maximum PSL and PersL from both Sm2+ and Sm3+ ions when annealed at 500 °C for 4 h. From a comparison with data for the macroscopic crystal (~3 mm) and ball-milled nanopowders (~30 nm), it also followed that PSL and PersL in the BaFCl:Sm system is a?ected by the crystal size. TL from Sm2+ of the macroscopic crystal is compared with the TL of sub-micron powders annealed at di?erent temperatures.
关键词： Storage phosphor,Photostimulated luminescence,Samarium,Thermoluminescence,Persistent luminescence
更新于2025-09-10 09:29:36
-
THERMOLUMINESCENCE OF NEWLY DEVELOPED HIGHLY SENSITIVE α-Al2O3:C BY THE VERTICAL GRADIENT FREEZING METHOD
摘要： A highly sensitive α-Al2O3:C crystal was directly grown by the vertical gradient freezing (VGF) method using Al2O3 and graphite powder as the raw materials. The main thermoluminescence (TL) characteristics of α-Al2O3:C detectors grown by the VGF method and TLD-500K detectors were compared. The α-Al2O3:C grown by the VGF method shows good dosimetric properties, such as high TL sensitivity (152 times higher than that of the TLD-100 at heating rate of 1°C/s), an extremely low residual signal of 0.03%, a minimum measurable dose of 0.12 μGy and an excellent linear response within the dose range studied from 1 μGy to 10 Gy. The α-Al2O3:C detectors grown by the VGF method have a higher sensitivity and a better linear response compared to the TLD-500K detectors. Both kinds of α-Al2O3:C can be used in an unannealed form and to measure the very low dose in environmental monitoring and personnel dosimetry.
关键词： α-Al2O3:C,personnel dosimetry,dosimetric properties,vertical gradient freezing method,thermoluminescence,environmental monitoring
更新于2025-09-09 09:28:46
-
Roman traces in Germania magna: New thermoluminescence and pIRIR <sub/>290</sub> data from a lime kiln at Bergisch Gladbach, Germany
摘要： The applicability of a post-infrared infrared stimulated luminescence (pIRIR290) protocol and two different thermoluminescence (TL) protocols—a single aliquot regeneration (SAR) and a multiple aliquot additive dose (MAAD)—was tested on six polymineral fine-grain (4–11 μm) samples extracted from the wall remains of a Roman lime kiln and a Roman roof tile. These remains had been excavated close to Bergisch Gladbach, which was at that time part of Germania magna. For the pIRIR290 measurements, no dependence of De on first-stimulation temperature was detectable, and the standard first stimulation temperature at 50°C was adopted. Fading tests and dose-recovery tests were made for all samples. Background subtracted glow curves were recorded up to 480°C for TL after a preheat of 220°C for 120 s. A-values were determined for all TL and pIRIR measurements. The results for all three protocols were fairly consistent, and TL and pIRIR290 protocols are shown to be suitable to estimate reliable equivalent doses for the fired kiln walls. The resulting ages are in agreement with the expected time range—Roman Iron Age—and with independent age control provided by radiocarbon ages of animal bones and charcoal from the firing chamber.
关键词： pIRIR290,GERMANIA MAGNA,THERMOLUMINESCENCE,POLYMINERAL,ROMAN LIME KILN,FINE GRAIN,LUMINESCENCE DATING
更新于2025-09-09 09:28:46
-
Tunable luminescent properties of BaGd <sub/>2</sub> O <sub/>4</sub> :Eu <sup>3+</sup> scintillating phosphors by Pr <sup>3+</sup> -codoping
摘要： BaGd2O4:Eu3+ scintillating phosphors by Pr3+‐codoping were synthesized at 1300°C in air using a solid‐state reaction method. The as‐synthesized phosphors were characterized by X‐ray diffraction (XRD), photoluminescence (PL) including excitation radioluminescence (RL) spectra excited by X‐ray and and emission spectra, thermoluminescence (TL) spectra. Both the PL and RL spectra are composed of the featured trivalent europium (Eu3+) without any praseodymium (Pr3+) ions, and the PL and RL intensities as well as the lifetimes of BaGd2O4:Eu3+ scintillating phosphors decrease dramatically with an increasing concentration of Pr3+ ions. Finally, the TL spectra reveal the trap concentration of the existing defects decrease with an increasing concentration of Pr3+ ions, while the relative TL intensity ratio of the high temperature band to the low temperature one increases with an increasing concentration of Pr3+ ions, which results in the afterglow suppression of BaGd2O4: Eu3+ scintillating phosphors.
关键词： radioluminescence,photoluminescence,BaGd2O4:Eu3+ scintillating phosphors by Pr3+‐codoping,thermoluminescence
更新于2025-09-09 09:28:46
-
X-Ray Thermoluminescence Dosimetry Characterization of Commercially Available CVD Diamond
摘要： High quality commercially available CVD diamonds are being tested in novel clinical high energy photons, hadron therapy, and high energy physics applications. In the present work, the authors report on the thermoluminescence (TL) and dosimetry properties of commercial synthetic CVD diamond sample from Element6, exposed to X-ray irradiation at dose rates of 3.9–120 Gy min?1 from 0.13 to 90 Gy. The TL glow curves are composed of four peaks with maxima at about 104, 150, 210, and 280 °C and activation energies of 0.78, 0.79, 0.81, and 1.0 eV, respectively. The dose response of the area under TL glow curves is linear at doses lower than 0.6 Gy, supralinear between 0.6 and 6 Gy and sublinear at higher doses. The samples exhibited a strong TL fading of the low temperature 104 °C peaks that fades away around 120 min after irradiation, which is accompanied by increasing of the 210 and 280 °C peaks. The measured TL cycle reproducibility was very good, in spite of the fading exhibited by the lower temperature peak, with values of 0.1–3.0% at different dose rates and doses. It is concluded that CVD commercially single crystal electronic grade diamond may be securely used in clinical radiotherapy.
关键词： dosimetry,fading,thermoluminescence,diamond CVD crystal,X-ray irradiation
更新于2025-09-09 09:28:46
-
Effect of Co-activation on the Thermoluminescence and Photoluminescence Properties of Nano-crystalline K2Ca2(SO4)3:Eu,Cu
摘要： The effect of co-doping and change in dopant concentration on thermoluminescence (TL) properties of K2Ca2(SO4)3:Eu,Cu has been studied by varying the concentration of the two dopants europium and copper (0.05, 0.10, 0.20, 0.30 and 0.40 mol % equally divided between Eu and Cu). Chemical co-precipitation technique was used to prepare the co-doped phosphor K2Ca2(SO4)3:Eu,Cu. Using Williamson-Hall plot in the X-ray diffraction pattern of the phosphor, the size of the crystallites was estimated to be around 51.3-73.6 nm. Maximum TL sensitivity was obtained for 0.2 mol% concentration (0.1 mol% Eu and 0.1 mol% Cu). The co-doped phosphor was compared for its TL sensitivity with that of the singly doped phosphors K2Ca2(SO4)3:Eu, and K2Ca2(SO4)3:Cu and the standard TL dosimeter LIF:Mg, Ti (TLD-100). Higher TL peak intensity of co-doped phosphor compared to the singly doped phosphors K2Ca2(SO4)3:Eu and K2Ca2(SO4)3:Cu has been explained on the basis of energy transfer between the dopants. Photoluminescence studies of the co-doped and the singly doped samples confirm a positive energy transfer from Cu2+ to Eu2+. A linear TL response curve over a wide range of doses (10 Gy to 1 kGy) is a key factor that makes the present phosphor quite capable for dosimetric purposes.
关键词： radiation dosimetry,up-conversion,nanophosphor,photoluminescence,thermoluminescence
更新于2025-09-04 15:30:14
-
The influence of dopants on thermoluminescence of Sr2MgSi2O7
摘要： We report the influence of dopants on the thermoluminescence of Sr2MgSi2O7. Samples studied comprise undoped Sr2MgSi2O7 and doped versions, namely, Sr2MgSi2O7:Dy3+, Sr2MgSi2O7:Eu3+, Sr2MgSi2O7:Tb3+ and Sr2MgSi2O7:Tb3+,Eu3+ phosphors. All samples show a broad glow peak near 60oC when measured at 1 °C/s after irradiation to 10 Gy. The peak changes with partial heating, irradiation and fades between irradiation and measurement in a manner expected of a composite one. The behaviour is used to exemplify the analysis of a composite peak on the basis that particular features reflect those of the dominant component.
关键词： dose response,thermoluminescence,glow curve,phosphor
更新于2025-09-04 15:30:14
-
Effect of Er3+ on NaSrB glass: thermoluminescence and structural analysis
摘要： The present work reports the investigations on Er3+-doped sodium–strontium–borate glasses for their structural, optical and thermoluminescence (TL) properties. While the amorphous nature of the prepared glasses is confirmed by the powdered X-ray diffraction (XRD), some interesting features were found in the structure and Fourier-transform infrared (FTIR) studies such as the nanocrystallization and the presence of BO3 and BO4 structural units. Some physical parameters such as ion concentration, polaron radius, inter-nuclear distance, and field strength are calculated and analyzed. Optical band gap was found to be sensitive to the concentration of the dopants. TL glow curve exhibits a single peak but it shifts with variation in concentration of Er2O3. Calculation of kinetic parameters show that the prepared glasses exhibit second-order kinetics. The effective atomic number (Zeff) of prepared glasses is also calculated which indicates their suitability for application in radiation dosimetry.
关键词： thermoluminescence,sodium–strontium–borate glasses,optical properties,radiation dosimetry,Er3+-doped,structural analysis
更新于2025-09-04 15:30:14