Gamma induced thermoluminescence and color centers study of Dy doped LiF micro-cubes

In this paper, we present the thermoluminescence and optical absorption studies of Dy-doped LiF phosphors. The phosphors were synthesized via co-precipitation method, in which the reactions were carried out at fixed pH value 8.00. X-ray diffraction (XRD) patterns revealed single phase structure of phosphors up to concentration (0.04 mol%) of Dy in the host lattice of LiF. The field emission scanning electron microscope (FE-SEM) images showed micro-cubical morphologies. The incorporation of Dy in LiF was confirmed from the results of electron dispersive spectroscopy (EDS) and XRD. The thermoluminescence (TL) glow curves of γ-irradiated samples in the dose range (0.1–50 kGy) revealed a main dosimetric glow peak positioned at 417 K. Moreover, at irradiation dose of 10 kGy and above, a broad TL band towards higher temperature side of main dosimetric peak also appeared. Using TLanal program, the complex TL glow curves were deconvoluted and TL kinetics parameters namely; the activation energies, frequency factors and order of kinetics were evaluated. The results revealed the formation of additional localized trapping sites of different values of activation energy and frequency factor in the forbidden band. The optical absorption study revealed the formation of radiation induced stable color centers (CCs) at room temperature. The concentrations of CCs were evaluated using Smakula's formula.     

Characteristics of pulsed photo-stimulated luminescence and thermoluminescence for the identification of gamma irradiated poultry eggs

Pulsed photo-stimulated luminescence (PPSL) is a simple screening method that can be employed qualitatively at the spot for the detection of eggs treated with ionizing radiation.Due to the variations in the results during storage,the eggs of ostrich,duck,hen,and quail were irradiated to doses of 0,1,2,and 3 kGy.Most of the samples were incorrectly identified during storage after four months of irradiation.Thermoluminescence (TL) technique was also tried by using egg shells in order to confirm the irradiation treatment in eggs.TL glow curves were recorded between the temperatures 50℃to 400℃at the rate of 5°/s for all the control and irradiated samples.On the basis of integrated areas of first glow curves (TL1),the glow curve ratios (TL1/TL2) and the shapes of maxima of TL1, the irradiation treatment of all the eggs was confirmed.Furthermore,the presence of calcite and aragonite minerals that cause the TL signal in the egg shells were studied using X-ray diffraction spectrometry.     

Comparisons of dosimetric properties between GD-300 series of radiophotoluminescent glass detector: and GR-200 series of thermoluminescent detectors

In order to compare the dosimetric properties of two kinds of solid state detectors used for monitoring external exposures,experiments Were performed for the GD-300 series of radiophotoluminescent glass detectors (RPLGD) and the GR-200 series of thermoluminescent detectors (TLD).X-rays and 137 Cs and 60 Co γ-rays were used to irradiate the RPLGDs and TLDs,their dose linearky,uniformity/reproducibility of signal,fading effect and energy dependence were compared.Both kinds of the detectors have generally good dosimetric properties.The dose linearity and energy dependence of the GD-351 dosimeters and the TLDs are nearly the same,but the RPLGD is much better than the TLD in terms of the uniformity and fading effect.     

从热释光到光释光

扼要地评述了以晶体的辐射效应为基础的热释光测年和光释光测年两种测年技术方法的进展，关系以及问题。     

参加重LAEA个人剂量监测比对研究的总结

国际原子能机构(IAEA)于1988年4月—1989年4月组织了一次个人剂量监测比对。参加这次比对的有包括中国辐射防护研究院个人剂量监测实验室在内的19个国家的21个实验室。本文介绍本实验室参加这次比对测量的情况和结果。     

Radiation-induced luminescence in magnesium aluminate spinel crystals and ceramics

Radioluminescence (RL) and thermoluminescence (TL) in spinel crystals and ceramics were investigated to elucidate the radiation-induced electronic processes in single crystals grown by Verneuil and Czochralski methods as well as transparent and translucent ceramics. Both RL and TL spectra demonstrate a UV-band related to electron–hole recombination luminescence at intrinsic defects; green and red luminescence are identified with emission of Mn²⁺- and Cr³⁺-ions, respectively. The kinetics of growth of different RL luminescence bands depending on dose at the prolonged X-irradiation shows the competitive character of charge and energy transfer between defects and impurity ions. The dependence of RL intensity on the temperature of the sample was measured in the range of 300–750 K and compared with TL for different emission bands. The variety of maxima in the temperature dependence of RL and in the glow curves of TL measured for different luminescence bands in spinels of different origins and crystalline forms is used to show that charge carrier traps and luminescence centers are not isolated defects but are complexes of defects and impurities. The formation, structure and properties of these complexes depend on the processing conditions.     

Photoinduced emission and thermoluminescence in topaz

Topaz has been demonstrated to be useful for dosimetric application. This mineral exhibits a satisfactory thermoluminescent (TL) response to radiation. In previous studies we analyzed the natural topaz samples from Minas Gerais, Brazil, by TL, infrared and X-ray diffraction techniques, with the aim of obtaining an explanatory model for the process of light emission of this mineral. Thermal treatments and irradiations do not produce significant changes in the TL emission. TL spectra exhibit a broad band with a maximum TL intensity at 420 nm in all the samples. In order to better understand the physical processes involved in the light emission of the topaz, we analyzed the photoinduced fluorescence of natural (as received) and thermally treated samples in powder form. The photoinduced emission of topaz was found to be similar to that of other silicates. In the UV–visible range there are intense emission bands between 350 and 550 nm, with a maximum intensity at 435 nm. The intensities are different for each sample.     

前剂量饱和指数法测定中国瓷器年代

用前剂量饱和指数法测定了23件中国瓷器的年代,结果表明,热释光年代与考古年代在一个标准偏差为27％以内的一致性非常良好,这样的误差在瓷器的年代测定中是可以接受的。     

瓷器热释光高温信号特征研究

对32个不同时代和地点的瓷器进行了热释光高温信号的检测,结果表明,除4个古瓷器和现代瓷器没有热释光高温信号外,其它古瓷器都有明显的高温信号,而且都呈单峰,但发光强度和高温峰的位置各不相同,古瓷器对于人工β,α辐照有较好的响应。     

Li2B4O7:Cu,In的热释光晒退特性研究

制得一系列不同烧结温度的Li2B4O7Cu,In样品,以X光衍射(XRD)、热释光(TL)、光释光(OSL)等手段研究样品的热释光陷阱的晒退特性.烧结温度对热释光陷阱的晒退特性影响较大,实验表明750℃烧结样品的热释光不易晒退.结合XRD和OSL的结果解释了烧结温度对晒退特性的影响.