Calibration of X-ray telescope prototypes at PANTER

We report on a ground X-ray calibration of two X-ray telescope prototypes at the PANTER X-ray Test Facility, operated by the Max-Planck-Institute for Extraterrestrial Physics, in Neuried, Germany.The X-ray telescope prototypes were developed by the Institute of Precision Optical Engineering(IPOE)of Tongji University, in a conical Wolter-I configuration, using thermal glass slumping technology.Prototype #1 with three layers and Prototype #2 with 21 layers were tested to assess the prototypes’ onaxis imaging performance. The measurement of Prototype #1 indicates a Half Power Diameter(HPD) of 82′′ at 1.49 keV. As for Prototype #2, we performed more comprehensive measurements of on-axis angular resolution and effective area at several energies ranging from 0.5–10 keV. The HPD and effective area are111′′ and 39 cm^2 at 1.49 keV, respectively, at which energy the on-axis performance of the prototypes is our greatest concern.

SMONTE CARLO CALCULATION FOR CALIBRATION FUNCTIONS IN TOTAL REFLECTION X-RAY FLUORESCENCE SPECTROMETRY

Simulation approach includes such processes as photon emissions from X-ray tube with a spectral distribution, total reflection on the sample support, photoelectric effect in thin layer sample, as well as characteristic line absorption and detection. The calculation results are in agreement with experimental ones.

Self Consistent Calibration of Detectors and Sources for Hard and Soft X-Ray Diagnostics

X-Ray sources, detectors and optical components are now used in a wide range of applications. What is crucial is the absolute calibration of such devices to permit a quantitative assessment of the system under study. A new X-ray laboratory has been built in Frascati (ENEA) to develop diagnostics for nuclear fusion experiments and study applications of these X-ray techniques in other domains, like new material science, non destructive tests and so on. An in-house developed selfconsistent calibration procedure is described that permits the absolute calibration of sources (X-ray emitted fluxes) and detectors (detection efficiencies) as function of the X-ray photon energy, in the range 2 - 120 keV. The calibration procedure involves the use of an in-house developed code that also predicts the spectral response of any detector in any experimental condition that can be setup in the laboratory. The procedure has been then applied for the calibration and characterisation of gas and solid state imaging detectors, such as Medipix-2, GEM gas detector, CCD camera, Cd-Te C-MOS imager, demonstrating the versatility of the method developed here.

A study on some elements and their phases in sediments of Changjiang Estuary by X-ray spectrometer and X-ray diffractometer

INTRODUCTIONThe studies on the quantitative distribution of the conventional elements and their phases in the sediments of the Changjiang Estuary are of great importance to the understanding of the chemical processes of ion exchange, absorption, desorption and flocculation in the estuary.

A New Method for Measurements of the Poloidal Rotation Velocities and Wavelength Calibration of X-ray Imaging Crystal Spectrometer in Magnetic Fusion Devices

A new simple method is presented for the wavelength calibration and measurement of poloidal rotation velocities with X-ray imaging crystal spectrometer（XICS）in magnetic fusion devices.In this method,the toroidal rotation of plasma is applied for high precise alignment and wavelength calibration of the poloidal XICS.The measurement threshold of poloidal rotation velocity can be lowered to 1-3 km/s with this method.

Detailed calibration of the PI-LCX：1300 high performance single photon counting hard x-ray CCD camera

X-ray charge-coupled-device（CCD） camera working in single photon counting mode is a type of x-ray spectrometer with high-sensitivity and superior signal-to-noise performance. In this study, two single photon counting CCD cameras with the same mode（model： PI-LCX： 1300） are calibrated with quasi-monochromatic x-rays from radioactive sources and a conventional x-ray tube. The details of the CCD response to x-rays are analyzed by using a computer program of multi-pixel analyzing and event-distinguishing capability. The detection efficiency, energy resolution, fraction of multi-pixel events each as a function of x-ray energy, and consistence of two CCD cameras are obtained. The calibrated detection efficiency is consistent with the detection efficiency from Monte Carlo calculations with XOP program. When the multi-pixel event analysis is applied, the CCDs may be used to measure x-rays up to 60 ke V with good energy resolution（E /？E ≈ 100 at60 ke V）. The difference in detection efficiency between two CCD cameras is small（5.6% at 5.89 ke V）, but the difference in fraction of the single pixel event between them is much larger（25% at 8.04 ke V）. The obtained small relative error of detection efficiency（2.4% at 5.89 ke V） makes the high accurate measurement of x-ray yield possible in the laser plasma interaction studies. Based on the discrete calibration results, the calculated detection efficiency with XOP can be used for the whole range of 5 ke V–30 ke V.

Calibrating the linearity between grayscale and element content for X-ray KES imaging of alloys

Doped elements in alloys significantly impact their performance.Conventional methods usually sputter the surface material of the sample,or their performance is limited to the surface of alloys owing to their poor penetration ability.The X-ray K-edge subtraction(KES)method exhibits great potential for the nondestructive in situ detection of element contents in alloys.However,the signal of doped elements usually deteriorates because of the strong absorption of the principal component and scattering of crystal grains.This in turn prevents the extensive application of X-ray KES imaging to alloys.In this study,methods were developed to calibrate the linearity between the grayscale of the KES image and element content.The methods were aimed at the sensitive analysis of elements in alloys.Furthermore,experiments with phantoms and alloys demonstrated that,after elaborate calibration,X-ray KES imaging is capable of nondestructive and sensitive analysis of doped elements in alloys.

Functional Confirmation Using a Medical X-Ray System of a Semiconductor Survey Meter

In recent years, semiconductor survey meters have been developed and are in increasing demand worldwide. This study determined if it is possible to use the X-ray system installed in each medical facility to calculate the time constant of a semiconductor survey meter and confirm the meter’s function. An additional filter was attached to the medical X-ray system to satisfy the standards of N-60 to N-120, more copper plates were added as needed, and the first and second half-value layers were calculated to enable comparisons of the facility’s X-ray system quality with the N-60 to N-120 quality values. Next, we used a medical X-ray system to measure the leakage dose and calculate the time constant of the survey meter. The functionality of the meter was then checked and compared with the energy characteristics of the meter. The experimental results showed that it was possible to use a medical X-ray system to reproduce the N-60 to N-120 radiation quality values and to calculate the time constant from the measured results, assuming actual leakage dosimetry for that radiation quality. We also found that the calibration factor was equivalent to that of the energy characteristics of the survey meter.

The development,performances and applications of the monochromatic X-rays facilities in(0.218–301)keV at NIM,China

Space scientific exploration is rapidly becoming the primary battlefield for humankind to explore the universe.Countries worldwide have launched numerous space exploration satellites.Accurate calibration of the detectors on the ground is a crucial element for space science satellites to obtain observational results.For the purpose of providing calibration for various satellite-borne detectors,multiple monochromatic X-rays facilities have been built at the National Institute of Metrology,P.R.China(NIM).These facilities mainly pertain to grating diffraction and Bragg diffraction,and the energy range of the produced monochromatic X-rays is 0.218–301 ke V.These facilities have a high performance in terms of energy stability,monochromaticity,and flux stability.The monochromaticity was greater than 3.0%.The energy stability of the facility is 0.02%at 25 ke V over 8 h,and the flux stability was within 1.0%at 25 ke V over 8 h.Calibration experiments on the properties of satellite-borne detectors,such as energy linearity,energy resolution,detection efficiency,and temperature response,can be conducted at the facilities.Thus far,the calibration of two satellites has been completed by the authors,and the work on three other satellites is in progress.This study will contribute to the advancement of X-ray astronomy the development of Chinese space science.

Elemental and proximate analysis of coal by x-ray fluorescence assisted laser-induced breakdown spectroscopy

Although laser-induced breakdown spectroscopy(LIBS),as a fast on-line analysis technology,has great potential and competitiveness in the analysis of chemical composition and proximate analysis results of coal in thermal power plants,the measurement repeatability of LIBS needs to be further improved due to the difficulty in controlling the stability of the generated plasmas at present.In this paper,we propose a novel x-ray fluorescence(XRF) assisted LIBS method for high repeatability analysis of coal quality,which not only inherits the ability of LIBS to directly analyze organic elements such as C and H in coal,but also uses XRF to make up for the lack of stability of LIBS in determining other inorganic ash-forming elements.With the combination of elemental lines in LIBS and XRF spectra,the principal component analysis and the partial least squares are used to establish the prediction model and perform multi-elemental and proximate analysis of coal.Quantitative analysis results show that the relative standard deviation(RSD) of C is 0.15%,the RSDs of other elements are less than 4%,and the standard deviations of calorific value,ash content,sulfur content and volatile matter are 0.11 MJ kg,0.17%,0.79% and 0.41%respectively,indicating that the method has good repeatability in determination of coal quality.This work is helpful to accelerate the development of LIBS in the field of rapid measurement of coal entering the power plant and on-line monitoring of coal entering the furnace.

Establishment and study of a polarized X-ray radiation facility

With the advancement in X-ray astronomical detection technology,various celestial polarization detection projects have been initiated.To meet the calibration requirements of polarimeters on the ground,a polarized X-ray radiation facility was designed for this study.The design was based on the principle that X-rays incident at 45°on a crystal produce polarized X-rays,and a second crystal was used to measure the polarization of the X-rays produced by the facility after rotation.The effects of different diaphragm sizes on the degree of polarization were compared,and the facility produced X-rays with polarization degrees of up to 99.55±0.96%using LiF200 and LiF220 crystals.This result revealed that the polarization of incident X-rays is one of the factors affecting the diffraction efficiency of crystals.The replacement of different crystals can satisfy the calibration requirements of polarized X-ray detectors with more energy points in the energy range(4-10)keV.In the future,the facility should be placed in a vacuum environment to meet the calibration requirements at lower energies.

Quantitative Analysis of FeMo Alloys by X-Ray Fluorescence Spectrometry

A quantitative analysis method of molybdenum in FeMo alloys by X-ray spectrometry using borate fusion technique was compared with that with pressed pellet. The complete pre-oxidation of FeMo alloys for the preparation of homogeneous fused discs was achieved by employing an automated fusion machine equipped with specially designed O2-blowing nozzles, which used lithium tetra-borate as flux with the addition of lithium nitrate (LiNO3) as oxidizer. The calibration curves of Mo and Fe were used in the quantitative analysis of standard materials and unknown plant samples with satisfactory accuracy and precision, utilizing the corrections of the matrix effects and line overlap. It was confirmed that the newly proposed method of preparing fused glass discs of FeMo alloys can replace the conventional wet chemical analyses requiring the labor intensive and time consuming procedure.

Determination of Optimum Conditions for X-Ray Fluorescence Analysis Using Coupling Equations

Coupling equations used to calculate the chemical composition of substances by X-ray fluorescence analysis can be classified as empirical, theoretical or semi-empirical based on the method for determining the coefficients of the calibration function. The advantages and disadvantages of each class of equations are discussed. Recommendations for the selecting the optimum conditions for determining empirical correction coefficients and their control during analysis are provided.

Radiological and X-Ray Diffraction Characterization of Bauxite and Rutile Ore Contaminated Environment in Kanam and Wase Mineral Exploration Sites, Plateau State-Nigeria

Two non-destructive analytical techniques (gamma spectrometer and X-ray diffractometer) were employed in the analysis of bauxite and rutile ore and their vicinity soil and control sourced within the Kanam and Wase mineral exploration sites. The activity concentrations of natural radionuclides 238U, 232Th, and 40K in the soil samples received from bauxite and rutile mineral mining vicinities revealed high concentrations of 238U, 232Th, and 40K compared to the control soil samples sourced 500 m away from the mineral exploration vicinities. Radiological detriments RLI, AUI, Hin and Hex unveiled values exceeding the radiation standard concentration (>1) for soil. X-ray diffraction characterization of bauxite ore revealed the interlocking minerals of Bauxite (18)%, Albite (11)%, Garnet (15)%, Illite (6)% and Muscovite (43)% in various proportions obtained within the 2θ range (9.18 to 64.4) and a peak value (intensity, cps) of 3400. Pure bauxite percentage in the ore meets metallurgical grade (15 - 25)%. X-ray diffraction of rutile ore revealed the minerals of rutile (40)%, quartz (21.4)%, ilmenite (27)% and garnet (11.8)% found within the 2θ range (27.5 to 35.6) and a peak value intensity of 31.1 - 100.0 cps also meeting the metallurgical grade of 15% - 25%. The major environmental concern associated with the mineral-sands industry is the radiation hazards, pollution of ground-water sources from heavy metals, mineral transport with heavy equipment’s, dredging operations in fragile coastal area and clearing of vegetation.

基于信号幅度的^(3)He管中子探测器刻度算法优化研究

本研究针对中国散裂中子源下的高压中子衍射谱仪中核心组件——位置灵敏型^(3)He管中子探测器的刻度问题进行了深入探究。通过实验验证和理论分析,揭示了传统刻度方法中未考虑到的中子信号幅度对刻度参数的影响,以及由此产生的位置分布畸变和空间分辨率降低的问题。为解决这些问题,本研究提出了一种改进的刻度算法,该算法能够有效地考虑中子信号幅度的变化,从而显著改善了探测器系统的空间分辨能力。经过实验结果分析显示,新的刻度算法不仅消除了位置分布的拖尾现象,而且提高了不同位置处的空间分辨率,与理论预期相符。本研究的成果为高压中子衍射谱仪在极端条件下的应用提供了重要的技术支持,并为进一步优化中子探测器的刻度方法和提高中子衍射技术的应用精度奠定了基础。

伊利石结晶度Kübler指数的校正与近变质带的确定

就像用"砝码"标定"称"来测量物质质量一样,伊利石结晶度的测量也需要这样的"砝码"标定它的测量工具——衍射仪,从而能够进行伊利石结晶度的测量和对比。这个砝码就是伊利石结晶度标样或称伊利石结晶度国际标样。第2届Kübler-Frey国际研讨会伊利石结晶度圆桌会议就伊利石结晶度标样和近变质带的确定的问题进行了深入的讨论。会议一致认为,用伊利石结晶度标样校正X射线衍射仪是极为重要和必要的,没有进行标样校正的伊利石结晶度数据将被拒绝发表,经过伊利石结晶度国际标样校正后的伊利石结晶度数据才可用于近变质带的划分和国际对比。本文就伊利石结晶度测量的有关衍射仪类型与差别,衍射仪系统,测量条件,样品的影响和国际标样对仪器的校正等问题进行了分析研究。结果表明不同型号仪器,同型号仪器不同测量条件与状态,样品的不同制备方法都将影响伊利石结晶度Kübler指数的测量。指出只有使用国际标样才可校正测量的伊利石结晶度Kübler指数,从而达到消除偏差准确划分近变质带的标准和进行国际对比的目的。

中国先进研究堆中子残余应力谱仪校准

为校准中国先进研究堆(CARR)中子残余应力谱仪,获得一维位置灵敏探测器(PSD)的灵敏度系数、位置坐标与衍射角的几何关系及零点等参数,设计了校准实验和软件,并将获得的校准参数用于标准Fe粉前4个衍射峰的数据预处理,校正衍射峰位与计算衍射角的差值符合残余应力谱仪的误差要求。结果表明,该工作能准确获得校准参数,并可用于CARR中子残余应力谱仪的数据预处理。

基于X射线衍射仪的X光晶体本征参量的标定

X光晶体本征参量的实验标定是准确鉴定X光晶体种类和品质,研制各种类型晶体谱仪,X光线谱定量测量和高分辨X光单能成像的基础.基于X射线衍射仪,通过制作平面晶体样品架,采取控制X射线管电源、滤波片选取和厚度控制等措施,极大地抑制了Cu-Kβ及韧致辐射,使X射线管光源Cu-Kα单能化,提出了用滤片作为光源单能化的判据.对X光线谱测量中常用的X光分光晶体季戊四醇[PET(002)]的晶格常量2d和Cu-Kα能点的积分衍射效率Rc进行了标定方法研究,其标定值分别为(0.874 25±0.000 42)nm和(1.759±0.024)×10-4 Rad.基于X射线衍射仪的X光晶体本征参量的精密实验标定方法既快速高效,且十分方便和灵活.通过更换衍射仪的X射线管靶材,采取类似方法,可以标定其它能点的晶体积分衍射效率,可为X光晶体的本征参量库提供更多的标定数据.

X射线衍射仪角度校准的光学新方法

目前X射线衍射仪(XRD)的角度检定和校准测试主要依据JJG 629—1989《多晶X射线衍射仪检定规程》和JB/T 9400—2010《X射线衍射仪技术条件》等技术文件,具体方法是采用光学经纬仪或多面棱体等进行测试,该测量方法实际应用中存在一定难度,其次测量间隔较大,不能很好反映真实的角度误差规律.为此,提出了利用θ角和2θ角同轴并可独立运动的特点,组合采用光电自准直仪和小角度激光干涉仪等仪器,设计了一种新的XRD的角度校准方法,它能够自动快速地连续测量角度,取k=2时,扩展不确定度约1.2″.使用该方法测试能够精确得到θ和2θ轴的误差数据,可用于修正XRD测角误差,提高XRD测试精度.该方法也适用于同步辐射等大型衍射系统等其他需要角度校准的情况.

基于X射线衍射仪的X光晶体参数标定

基于实验室X射线衍射仪,利用其运行稳定性和高精度角度控制能力,通过设计、制作晶体样品架,对X光平面晶体的本征参数晶格常数和积分衍射效率进行了实验标定,并给出其不确定度。该方法快速、高效、方便、灵活,实现了X光晶体的实验室标定,为ICF物理实验线谱诊断设备晶体谱仪的定量化测量提供了数据支撑。