一种基于旋流分离原理光释光测年样品制备方法

光释光测年(OSL)样品制备的目标是提取土壤中一定粒径范围内的石英和长石颗粒(中颗粒38～63?μm).针对当前样品提取过程中效率低、耗时长等诸多问题,提出一种光释光测年样品制备新方法.该方法基于水力旋流分离原理,采用3D打印技术研制微型水力旋流器(浓缩器),设计2种改进型带筛网的微型水力旋流器(粗选器和精选器),根据...     

光磁存贮材料的现状与展望

利用光存贮信息或读出的装置称为光存贮器,使用的存贮介质叫做光存贮材料。利用光存贮信息的形式分为光学成像或者原形记录光束产生的图像信息的直接存贮和通过变换调整信息图像干涉条纹记录的全息照像存贮两大类(表1)。光技术用于磁记录领域的研究,虽然早在五十年代后期就已开始,     

成像板（IP）的使用和保养方法

计算机射线照相（CR）已在国内广泛推广,其成像过程是先把射线影像信息捕俘并储存在涂有氟氯化钡的成像板（IP）上。IP板通过扫描装置发出的激光,经计算机系统处理形成数字化图像,IP板在CR系统中起了传感器、存储器和发光器的作用,因此又称储存发光器（Storage Phosphor）,是整个CR系统的关键部件,本文扼要介绍其使用注意事项。     

双读出量能器用闪烁晶体研究进展

双读出量能器是一种全新设计的高能粒子探测装置, 它能同时测量到Cherenkov光和闪烁光, 因而能更全面地获得高能粒子的信息。目前, 双读出量能器主要有三种设计方式: (1)采用石英纤维产生Cherenkov光, 塑料闪烁纤维生成闪烁光; (2)分别以未掺杂的晶体纤维作为Cherenkov辐射体、Ce掺杂的同种晶体纤维作为闪烁体; (3)采用同种闪烁晶体有效分离Cherenkov光和闪烁光。第三种设计可以消除取样涨落、提高量能器的分辨率, 因而备受关注。本文基于第三种设计方式探讨了钨酸铅(PbWO₄)、锗酸铋(Bi₄Ge₃O₁₂)、硅酸铋(Bi₄Si₃O₁₂)和镥铝石榴石(Lu₃Al₅O₁₂)四种。闪烁晶体在双读出量能器方面的研究进展和可能的应用。Pr掺杂PWO晶体以及硅酸铋晶体都有可能用于双读出量能器, 而后者由于吸收边比锗酸铋更短, 更易于分离Cherenkov光和闪烁光, 在双读出量能器应用方面显示出明显的优势。稀土离子掺杂有望进一步提高硅酸铋晶体的性能, 开发出更适合双读出应用的闪烁材料。     

基于各向异性二维Ge Se的无偏振器偏振图像传感器

偏振是光的一个重要信息,偏振探测可以把信息量从三维(光强、光谱和空间)扩充到七维(光强、光谱、空间、偏振度、光偏振等),为成像物体提供关键的视觉信息(如表面粗糙度、几何形状或方向),因此偏振成像技术在目标检测等领域有着巨大的潜力.然而这些领域往往需要复杂的偏振编码,现有的复杂透镜系统和偏振器限制了集成成像传感器的小型化能力.本文通过二维各向异性α-Ge Se半导体,成功实现了无偏振器的偏振敏感可见-近红外光电探测器/成像仪.作为传感器系统的关键部件,该原型Au/GeSe/Au光电探测器具有灵敏度高、光谱响应宽、响应速度快(~10³A W^-1, 400–1050 nm, 22.7/49.5μs)等优点.此外,该器件在690–1050 nm光谱范围内表现出独特的偏振灵敏度,并且对沿y方向的偏振光吸收最强,这一点通过分析α-Ge Se的光跃迁行为也得到了证实.最后,将2D-Ge Se器件应用到成像系统中进行偏振成像,在808 nm近红外波段处,在不同的偏振方向上,辐射目标的对比度为3.45.这种成像仪在没有偏振器的情况下,能够在场景中感知双频偏振信号,为偏振成像传感器阵列的广泛应用奠定了基础.     

热机械光读出非制冷红外成像系统建模分析

针对热机械光读出非制冷红外成像系统缺乏系统级噪声模型的问题,本文提出了一种光电耦合模型.此模型以光电耦合器件的模式体现了光读出非制冷红外系统的噪声隔离特性.基于此模型,文中将系统噪声划分为由焦平面阵列(FPA)引入的内部噪声和由于光读出系统引入的外部噪声.理论计算显示,系统的内部噪声对应的噪声等效温差(NETD)为5.94 mK .实验结果显示,系统的外部噪声对应的NETD 与系统的总噪声对应的NETD 相当,为98 mK .此结果说明,理论模型中对内部噪声影响的推断是合理的,且光读出成像系统的噪声主要源自外部噪声.     

燃烧合成法制备IP板荧光粉工艺参数的研究

涂在IP板(Imaging Plate,简称IP)上的荧光粉BaFBrEu2+可存储X线影像,并通过光激励发光读出存储的光信息.BaFBrEu2+传统的制备方法是高温固相法,而燃烧合成法一直应用在合成金属氧化物和难熔金属之间的合成上,用这种方法制备不含氧的化合物还未见报道.本文报道了如何利用燃烧合成法制备IP板荧光粉一种不含氧的化合物,着重讨论了燃烧合成法的工艺对材料的结构和性能的影响.     

杜比CP650型数字影院声音处理器设置软件的使用(三)

5 .6杜比数字 (DolbyDigital)选择“杜比数字”选项卡 ,将自动地把CP65 0的制式设置到制式 1 0—杜比数字。它包括 4个选项组 :读出器延时、自动化杜比数字、反转方式和自动环绕EX。5 .6.1读出器延时 (ReaderDelay)通过对该选项组的调整 ,使数字声迹和模拟声迹与画面同步。它能够通过选择读出器类型或在使用Cat .No .1 0 1 0同步测试片时 ,通过手动校准齿孔数来设置。选择杜比数字读出器类型 (SelectDolbyDigitalReaderModel)这是杜比数字读出器类型列表框。具体的读出器类型选择示于表 5 -1。选择读出器的类型 ,就可以提供一个合适的…     

探测器响应度不均匀性对测量LED平均发光强度的影响

使用响应度分布不均匀的探测器来测量光分布不均匀LED的平均发光强度时,其测量结果可能会引入显著的测量误差。设计实验装置对3种不同类型的探测器的响应度分布进行测量,结果表明带光漫射器的光度探测器响应度均匀性很差,这样的光度探测器用于测量一种白光LED平均发光强度时,响应度不均匀引起的测量误差可达2.0%。类似于光谱失配修正方法,给出了对探测器响应度不均匀性评价的方法以及响应度不均匀性评价因子c的表达式,并建议在进行LED平均发光强度测量时,应避免使用带光漫射器的光度探测器。     

分析波分OLP／DCP扩展板内保护

传统波分扩展板内波长保护利用具有双发选收功能的OLP/DCP单板,发端使用分光器双发,收端采用光开关选收,实现对OTU单板业务在波分侧的保护,6800板内波长保护光层上原理和传统波分相同：利用具有双发选收功能的OLP/DCP单板,发端使用分光器双发,收端采用光开关选收,实现对OTU单板业务在波分侧的保护。     

Optically stimulated luminescence in an imaging plate using BaFi:Eu

BaFI:Eu phosphors are fabricated using a new method of synthesis: liquid phase synthesis, in which the phosphor particles are formed through the association of Ba2+ ions, F-ions and Eu2+ ions in solution. An intense optically stimulated luminescence (OSL) peak at about 410 nm is observed by stimulating X ray irradiated BaFI:Eu phosphor with about 550-750 nm light. It is found that the peak wavelength of the optically stimulation spectrum is about 690 nm. This result suggests that the semiconductor laser can be used as the stimulating light source. It is also found that the OSL intensity is increased with increasing the X ray dose. The BaFI:Eu phosphor as a photostimulable material for the imaging plate of a computed radiography system provides the following advantages; (1) high X ray absorption coefficient, (2) high monodispersion in size which would contribute to sharp images, (3) high OSL and thus low luminescence mottle and (4) high DQE (detective quantum efficiency).     

Introduction of the InLight monitoring service

A new external monitoring service has been developed combining the excellent features of optically stimulated luminescence (OSL) with the convenience of Panasonic readers. This article briefly reviews OSL, and describes the InLight personal dosimetry system and its introduction into the European market.     

TL and OSL of SrSO4 phosphors doped with Eu

The thermoluminescence (TL) and optically stimulated luminescence (OSL) of SrSO4:Eu (0.1 mol%) powder sample were studied. The TL and OSL emission spectrum are measured after irradiation (absorbed dose 100 Gy) of 90Sr source; both of them showed that the emission wavelength is at approximately 375 nm, which indicates that TL and OSL have the same luminescence centres, and the luminescence comes from transitions between the energy levels of Eu2+. The TL glow curves and OSL decay curves illustrate that there is only one main TL peak but two main components in OSL curves. By a comparative study of TL and OSL it is concluded that OSL traps are different from TL traps. The TL and OSL dose responses of SrSO4:Eu phosphor were measured, and it showed that phosphor has similar dose responses for OSL and TL.     

Thermoluminescence glow curves and optical stimulated luminescence of undoped alpha-Al2O3 crystals

The characteristics of thermoluminescence (TL) and optical stimulated luminescence (OSL) in undoped alpha-Al2O3 single crystals were studied. The TL glow curves of the crystal samples irradiated at various dose levels were measured by Ris? TL/OSL-DA-15B/C reader with U-340 or 7-59 filters at different heating rates. The glow peaks measured with U-340 at approximately 210 degrees C of the undoped alpha-Al2O3 can be well fitted by first-order kinetic equation whereas the glow peaks measured with 7-59 filters are a composite of two first-order glow peaks. It indicates that the TL glow curves are dependent upon the filter used in the reader that is related to the emission spectra of luminescence materials. The OSL were also measured and fitted by two exponential functions to get the luminescence intensities. The TL and OSL dose responses of the undoped alpha-Al2O3 crystal were obtained in the dose range of 0.12-248 Gy and fitted by the composite action dose-response function to get nonlinear characteristic parameters. The TL and OSL dose responses are linear-sublinear.     

Eu-doped CsBr phosphor as a new optically-stimulable phosphor material for medical X-ray imaging sensor

CsBr phosphor ceramics doped with different luminescence centres such as In2O3, Eu2O3, EuCl3, SmCl3, TbCl3, GdCl3 or NdCl3 as the candidate for a new optically-stimulable phosphor for medical X-ray imaging sensor were prepared using a conventional ceramic fabrication process. It was found that X-ray-irradiated Eu-doped CsBr (CsBr:Eu) exhibited intense optically stimulated luminescence (OSL). The peak wavelength of the OSL emission and stimulation spectra of CsBr:Eu phosphor ceramic sample were 450 and 690 nm, respectively. The dependence of OSL properties on the conditions of preparation of phosphor ceramic samples, such as Eu concentration, sintering temperature and sintering time, were studied. The optimum preparation conditions were also studied. It was found that the OSL intensity of CsBr:Eu phosphor ceramics fabricated under optimum preparation conditions is higher than that of commercially available imaging plates using BaFBr:Eu.     

The use of optically stimulated luminescence from AL2O3:C in the dosimetry of high-energy heavy charged particle fields

This paper presents two different approaches of quantifying the optically stimulated luminescence (OSL) response of Al(2)O(3):C to high-energy heavy charged particles (HCPs). The OSL efficiency of Al(2)O(3):C exposed to different HCPs is defined as the sensitivity of the material to HCPs normalised by the sensitivity to gamma. In this paper, we investigate the possibility of introducing a 'mean efficiency' eta(mean), which when used in conjunction with the total gamma dose D(gamma) measured for a mixed radiation exposure allows for the determination of the absorbed dose without the need to determine the individual contributions of different types of radiation to the OSL signal. We tested the hypothesis that information regarding the 'mean efficiency' eta(mean) is contained in the shape of the OSL decay curve, using several approaches in the analysis of the OSL data. This analysis was applied to various mixed field irradiations performed at the HIMAC facility, Chiba, Japan. The results of this analysis are discussed.     

Blue light stimulated luminescence in calcium fluoride, its characteristics and implications in radiation dosimetry

Strong optically stimulated luminescence (OSL), stimulated by blue light, has been observed, for the first time, in natural calcium fluoride (CaF(2)) phosphor, used as thermoluminescence dosemeters. Traps responsible for all three thermoluminescence (TL) peaks appearing upto 300 degrees C, i.e. 126, 196 and 264 degrees C, were observed to contribute to the blue light stimulated luminescence (BLSL) in CaF(2). When the areas under the respective curves (BLSL and TL) were measured, the BLSL measured at room temperature was found to be approximately 1.8 times the TL output of the dosimetry peak that appeared at approximately 264 degrees C. However, when measured after thermally annealing the first two TL peaks, the BLSL signal was found to be 0.26 times the TL output of the dosimetry peak at 264 degrees C. This paper describes the characteristics of the BLSL signal using linearly modulated OSL after subjecting the phosphor to different annealing treatments. Feasibility studies to assess the usefulness of BLSL in CaF(2) for environmental radiation monitoring are also discussed.     

Independent evaluation of optically stimulated luminescence (OSL) 'dot' dosemeters for environmental monitoring

Optically stimulated luminescence (OSL) 'dot' dosemeters (manufactured by Landauer?) are reported to have a high degree of environmental stability, high level of sensitivity and provide wide range of dose measuring capabilities from 0.05 mGy to 100 Gy. The optical read out method is fast and relatively simple and permits repeated read out, but few studies have been performed about its application in monitoring radiation in the environment. This study was initiated to independently test the performance of OSL dot dosemeters for the application of measuring doses of radiation in the outdoor environment. Testing was performed in the laboratory to evaluate reproducibility and stability and in the field to evaluate accuracy relative to calibrated high-pressure ionisation chambers. The results showed that OSL dot dosemeters had good reproducibility and stability in both laboratory and field tests and met the performance requirements of standards of the American National Standards Institute.     

Kinetic features of optically stimulated luminescence in aluminum nitride powder

Room-temperature optically stimulated luminescence (OSL) response in UV-irradiated aluminum nitride (AlN) powders has been studied. Excitation of AlN powder by UV photons with energies within 3–5 eV gives rise to an intense afterglow that is related to isothermal quenching of recombination processes involving shallow donor centers. It is established that a useful OSL response separated on the background of this recombination afterglow represents a superposition of two components with decay kinetics order b = 1.0–1.2 and 1.7–2.1. Superlinear UV-dose dependences of the OSL light sum have been measured and the corresponding coefficients for each component have been analyzed in comparison to the available published data.     

Optical dating of palaeochannel deposits in the Riverine Plain,southeastern Australia: testing the reliability of existing thermoluminescence dates

We present the first quartz optically stimulated luminescence (OSL) ages for palaeochannel sediments from the Riverine Plain in southeastern Australia. For young fluvial sediments, we agree with the notion that analysis of the leading edge of a dose distribution curve provides an objective method for determining the OSL age. For a modern flood deposit (less than 200 years old), the OSL ages estimated using the leading edge method (250 +/- 50 years) and by using the lowest 5% of the measured dose in single aliquots (230 +/- 50 years) agree within experimental errors. For older sediments, we suggest that the mean estimate of the dose distribution is likely to provide a reliable estimate of the OSL age. The luminescence ages suggest that the Coleambally and Kerarbury palaeochannel systems were active between 105 and 80 ky and 55 and 35 thousand years ago; the Yanco palaeochannel system could have been active as recently as 9000 years ago.