共查询到20条相似文献,搜索用时 10 毫秒
1.
In the present paper Na3SO4Cl:Ce, Na3SO4Cl:Dy, Na3SO4Cl:Mn, of Na3SO4Cl:Ce, Dy and Na3SO4Cl:Ce, Mn phosphor were synthesized by the wet chemical method. Thermoluminescence (TL) characteristics of Na3SO4Cl:Ce, Na3SO4Cl:Dy, Na3SO4Cl:Mn, Na3SO4Cl:Ce, Dy and Na3SO4Cl:Ce, Mn phosphors were studied for 5 Gy γ-ray dose. In TL glow curve, two peaks have been observed at 129°C and 224°C for different concentrations of Ce and Dy, whereas Mn peaks at 212°C. The same host is also tried for Ce, Dy (peaks at 126, 219) and Ce, Mn (248°C). A significant single peak is observed in the case of Na3SO4Cl:Mn and Na3SO4Cl:Ce, Mn. This may be due to the effect of activators. It is found that intensity tends to be increase with increased concentrations of the activators. The TL glow curves of the phosphors have been recorded and irradiated at a rate of 0.39 kGy h?1 for 5 Gy γ-rays dose. It is also found that all the phosphors are less sensitive as compared with Thermoluminescence dosimetry-CaSO4: Dy for the same γ-rays dose. The paper discuses the preliminary TL characteristics and effect of γ-rays on Na3SO4Cl:Ce, Na3SO4Cl:Dy, Na3SO4Cl:Mn, Na3SO4Cl:Ce, Dy and Na3SO4Cl:Ce, Mn phosphors. 相似文献
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K. V. R. Murthy Y. S. Patel A. S. Sai Prasad V. Natarajan A. G. Page 《Radiation measurements》2003,36(1-6):483-485
The present paper reports studies on the applicability of fluorescent lamp phosphors in accidental radiation dosimetry. Strontium orthophosphate, which is used as one of the components in the fluorescent lamps, has been studied for its thermo-luminescence (TL) characteristics on exposure to different doses of beta irradiation. The analysis of the TL glow curve of the phosphor, with a well-defined glow peak at 553 K, and other experiments carried out have proved the utility of strontium orthophosphate as dosimetric material in the range of 10–200 Gy. It has been observed that the material satisfies most of the fundamental criteria for a good TLD-material. A fluorescent lamp developed with this material as TLD grade lamp phosphor is thus expected to serve twin purposes of providing illumination and monitoring the radiation released during a nuclear accident. 相似文献
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Modern advances in radiation medicine – radiodiagnosis, radiotherapy and interventional radiography – each present dosimetry challenges for the medical physicist that did not exist previously. In all of these areas a constant balance has to be made between the treatment necessary to destroy the tumor and the unnecessary exposure of healthy tissue. Innovative applications of OSL dosimetry are now appearing in each of these areas to help the medical physicist and oncologist design the most effective, and least deleterious, treatment for their patients. High sensitivity, precise delivery of light, fast readout times, simpler readers and easier automation are the main advantages of OSL in comparison with TLD.This work aimed to study the application of OSL technique using lithium fluoride dosimeters doped with magnesium and titanium (LiF:Mg,Ti) for application in beta and gamma dosimetry. 相似文献
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用热释光三维发光谱仪和蓝色滤光片的热释光仪测定了CaSO4:Eu2+的辐照后的发光曲线,得到峰温为107和144℃波长390nm的发光峰.辐照50d后,107℃发光峰已衰退,发光曲线呈现144℃单个发光峰.经一级力学方程式拟合得到的激活能E=(1.02±0.03)eV与初始升温法(1.07±0.01)eV和峰形法(1.02±0.01)eV的非常符合.用通用级动力学模型拟合发光曲线,得到陷阱能级E=(1.04±0.01)eV,频率因子s=(2.07±0.8)×1012s-1和动力学级数b=1.05±0.02
关键词:
CaSO4∶Eu
剂量响应
动力学参量
热释光 相似文献
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Cosmic radiation is one of the most important sources of human exposure to natural radiation. Data regarding the level of cosmic radiation in different areas of Pakistan are lacking. The aim of the present study was therefore to estimate the annual outdoor effective doses from cosmic radiation in the Punjab province of Pakistan. The Punjab province is located between geodetic latitudes 28° and 34° N, and longitudes 69° and 75° E. The mean value of the outdoor annual effective dose was found to be 333 μ Sv, which generates a radiation dose of 0.33 mSv y?1 per caput. This is 87% of radiation dose received by the population in the region from terrestrial sources reported elsewhere. The results of this study will contribute to regional as well as world data regarding the exposure of the population to cosmic radiation. 相似文献
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基于密度泛函理论下的平面波超软赝势方法,本文计算了102 GPa压力下LiF理想和含空位(Li-1 、F+1)晶体的电子结构和光学性质.结果表明:102 GPa压力下理想LiF晶体有良好的透明性;高压下Li-1及F+1两种空位的存在不影响LiF的光学透明性.分析其原因:LiF是一种带隙很宽的离子晶体,电子发生跃迁需要较高的能量; LiF中F元素的电负性很大,Li的电负性却很小,二者结合的Li-F键键能很高.另外本文还计算了102 GPa压力下理想LiF晶体及Li-1 、F+1两种空位分别存在时的反射、折射率、介电函数和光损失函数等一些光学性质,并将理想和含空位的做了比较,结果表明:102 GPa压力下空位的存在对LiF在可见光范围内这些光学性质都不产生影响,但由于F+1空位的存在使LiF晶体对光的吸收发生了红移现象. 相似文献
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ABSTRACTThe paper examines the influence of γ radiation on the stability of the insulation characteristics of the stator winding of rotating electrical machines. The tested insulation characteristics are loss tangent angle, resistance, polarization factor, threshold voltage of partial discharge, breakdown voltage, coefficient of proportionality and lifetime exponent. The radiation dose was used as the γ radiation parameter. Different winding areas have been specifically tested in which a different impact is expected on technological winding production process. Tests were performed on a representative statistical sample under well-controlled laboratory conditions. The combined measurement uncertainty of the experimental procedure was about 5%. 相似文献
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This paper reports on a thermoluminescence study of D2O ice Ih. A sample of hexagonal (Ih) ice is irradiated by a 100 MeV X-ray source at 77 K. The emission spectrum that is measured immediately after the end of the irradiation process has the thermoluminescent behaviour of amorphous ice. The kinetic transition is followed to the stable form, taking place at 85 K. The relaxation time of the transition is of the order of 5 minutes. It is concluded that, due to irradiation, a few outer layers of ice Ih are converted to the low-density amorphous form of ice, which then converts to cubic ice. Although complex to quantify, thermoluminescence appears to be, in the present study, particularly sensitive to the time evolution of irradiated samples. 相似文献
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采用溶胶-凝胶(Sol-Gel)技术,分别在空气中和石墨提供的弱还原气氛下制备出Lu2SiO5∶Ce0.006荧光粉。通过分析样品的结构,光致激发、发射谱和热释光谱等特性,发现弱还原气氛下制备的样品不仅光致发光强度比空气中的强,而且热释光曲线中598K处的高温热释光峰也得到了抑制。进一步考察空气中制备的Lu2SiO5∶Ce0.006,Kx(x=0.01~0.08)荧光粉,结果表明就光致发光和热释光特性而言,K+共掺杂具有与还原气氛类似的作用。综合以上两方面分析结果,可认为598K处热释光峰是由与Ce4+相关的缺陷引起的,并对K+共掺杂LSO∶Ce发光增强的原因给出了合理解释。 相似文献
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The dependence of LiF:Mg,Cu,P samples with various concentrations of Mg on sintering temperatures was investigated to find a new dosimeter. The influence of high sintering temperatures on LiF:Mg,Cu,P chips depends strongly on Mg concentrations. The height of the main peak versus the sintering temperatures exhibits a maximum, the position of which varies between 690 °C and 750 °C, depending on the Mg concentration in the range studied. The high temperature peaks of LiF:Mg,Cu,P for various Mg concentrations reduce basically when the sintering temperature is increased. LiF:Mg,Cu,P is much less sensitive than LiF:Mg,Cu,Si to sintering temperature. LiF:Mg,Cu,P with 0.6 mol% of Mg can be re-used at annealing temperature of 260 °C, regardless of the sintering temperature. It was found that the optimum concentration is Mg: 0.6 mol%, the optimum sintering temperature is 750 °C, considering that LiF:Mg,Cu,P with a low residual signal and good sensitivity can be re-used at annealing temperature of 260 °C and produced in a large scale. The new optimum LiF:Mg,Cu,P formation has 52 times higher than that of the TLD-100, and an extremely low residual signal of 0.07% without an initialization readout procedure. 相似文献
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Within a systematic study of a novel system enabling 2D readout of TL foils, the X-ray energy and dose response was investigated in TL foils containing LiF:Mg,Cu,P (MCP-N) or CaSO4:Dy as activators. Foils were exposed to broad X-ray beams of mean energies ranging between 45 keV and 208 keV (ISO 4037 standard), with reference to 662 keV 137Cs gamma rays. The MCP-N foils, of about 380 nm emission wavelength, show a flat X-ray energy response, but low sensitivity. Due to poor TL light detection efficiency of the CCD (charge-coupled device) camera over this range of wavelengths, only doses exceeding 500 mGy can be reliably measured. In the case of CaSO4:Dy foils, their TL light emitted around 450 nm wavelengths is registered by the CCD camera with no loss of efficiency, enabling X-ray doses as low as 100 mGy to be evaluated. Unlike that of MCP-N, the dose response of CaSO4:Dy foils is highly supralinear. Nevertheless, within experimental conditions applied in this study, the 2D-TL technique may be applied to determine Entrance Surface Dose or Maximum Skin Dose in radiology. The more sensitive CaSO4:Dy foils could be used only in a well-specified radiation field (e.g., in mammography) or in qualitative dose mapping. 相似文献
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Boris Lončar 《辐射效应与固体损伤》2013,168(12):903-912
The aim of this paper is to examine the reliability of erasable programmable read only memory (EPROM) and electrically erasable programmable read only memory (EEPROM) components subjected to the influence of gamma radiation. This problem is of considerable significance for both military industry and space technology. We present total dose results for the NM27C512 8F85 EPROM and M24128 – B W BN 5 T P EEPROM components. There is evidence that EPROM components radioactive reliability is better than that of EEPROM components. Furthermore, the changes EPROM's undergoes are reversible, so that after erasing process and reprogramming all EPROM components are fully functional. On the other hand, EEPROM's changes are irreversible and when subjected to the influence of gamma radiation, all EEPROM components become permanently nonfunctional. The obtained results are analyzed and explained via the interaction of gamma radiation with oxide layers. 相似文献
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Erasure of the thermoluminescence (TL) signal on detector readout is considered to be a disadvantage of TL dosimetry, as post-readout dose reassessment is then impossible in principle. A method of dose reassessment based on phototransferred thermoluminescence (PTTL) has been developed at the Institute of Nuclear Physics, Polish Academy of Sciences (IFJ PAN) and applied to MTS-N (LiF:Mg,Ti) detectors. We demonstrate the possibility of applying PTTL for dose reassessment in MTS-N TL detectors routinely applied in the dosimetric service at IFJ PAN. Readings of TL detectors exposed to relatively high doses by the customers of our dosimetry service can now be reassessed using our automatic readers. A major obstacle in applying the PTTL method at lower exposures is the presence of residual dose accumulated in LiF:Mg,Ti detectors after many field exposure and readout cycles. Since most of the TL detectors in our service have been already used for a long time (e.g. for over 10 years in the case of some detector batches), we find that our PTTL method of dose reassessment is possible only in detectors which had received doses exceeding 5 mSv. 相似文献
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Functionalized polymers were prepared by radiation-induced graft copolymerization of binary monomer system acrylic acid/acrylamide (AAc/AAm) onto low-density polyethylene (LDPE) and polypropylene (PP) films using direct radiation-grafting technique. Sulfonation was carried out for the prepared grafted copolymers using concentrated sulfuric acid (97%) at 60 °C for 15 min. The grafted and sulfonated grafted films found to have good properties such as thermal stability and hydrophilic properties. The sulfonated grafted films found to have a better hydrophilic character than the grafted ones due to ionic character resulted by this conversion. The thermoluminescence (TL) characteristics of a set of grafted and sulfonated films have been studied with regard to their use as off-line dosimeters in radiotherapy. The structural characterization has been performed by means of infrared spectroscopy. Their TL responses have been tested with radiotherapy beams of 60Co photons in the dose range 0.1–7 Gy. The dosimetric characterization has yielded a very good reproducibility and is independent of the radiation energy. The TL signal is not influenced by the dose rate and exhibits a very low thermal fading. Moreover, the sensitivity of the samples compares favorably with that of the standard TLD100 dosimeters. Finally, at the same dose, the TL response for LDPE-g-P (AAm/AAc) films is higher than the PP-$g$-P(AAm$/$AAc), and the sulfonated grafted films are more sensitive to radiation than the grafted ones. 相似文献
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The optical absorption (OA) dose response of irradiated LiF:Mg,Ti has been measured over the dose range from 100 Gy to 1.4 M Gy. Measurements at high dose indicate that the 4.0 eV band is actually a composite band at 3.84 eV and 4.3 eV. Bleaching experiments at 5.08 eV (F band) support the participation of V3 centers in the relaxation mechanisms following the bleach. The results are interpreted in the framework of a spatially correlated trapping center/luminescent center giving rise to composite peak 5 in the glow curve. 相似文献
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提出了液体夹心法热导率测量技术,采用CHBr3液体作为夹心材料实现了样品/窗口界面的理想接触,并将动载荷作用下的夹心法高压热导率实验测量压力下限拓展至40GPa,为绝缘介电晶体高温高压热导率测量提供了技术支持.实验利用平面碰撞和DPS测试技术,结合液体夹心法实测了LiF单晶高压热导率数据,对现有热导率理论模型进行了研究和探讨,结果显示,在γ/γ0=(ρ0/ρ)2时,修正后的Roufosse理论公式与实验数据符合较好,这一研究结果为非透明材料冲击波温度测量中的热传导修正提供了实验数据和理论模型. 相似文献