ICF实验软X光能谱的基函数解谱法

 惯性约束聚变实验中,14通道软X光能谱仪是测量软X射线能谱、等效积分温度和辐射能流时间过程的重要诊断设备。基函数法是还原能谱分布的一种常用方法。通过对双峰谱形的还原,对不同类型基函数的选择、基函数参数的设置和求解方法等影响解谱的因素进行了比较分析。根据大量算例的结果,使用优化后的基函数和求解方法对实际测量辐射谱进行了计算,并与透射光栅谱仪的测量结果进行了比较。结果显示,根据谱仪通道响应选择三次样条的节点,能够较好还原软X射线的能谱。     

A general assignment method for oriented sample (OS) solid-state NMR of proteins based on the correlation of resonances through heteronuclear dipolar couplings in samples aligned parallel and perpendicular to the magnetic field

The acquisition and different appearances observed for wide bandwidth solid-state MAS NMR spectra of low-γ nuclei, using (14)N as an illustrative nucleus and employing two different commercial spectrometers (Varian, 14.1T and Bruker, 19.6T), have been compared/evaluated and optimized from an experimental NMR and an electronic engineering point of view, to account for the huge differences in these spectra. The large differences in their spectral appearances, employing the recommended/standard experimental set-up for the two different spectrometers, are shown to be associated with quite large differences in the electronic design of the two types of preamplifiers, which are connected to their respective probes through a 50Ω cable, and are here completely accounted for. This has led to different opportunities for optimum performances in the acquisition of nearly ideal wide bandwidth spectra for low-γ nuclei on the two spectrometers by careful evaluation of the length for the 50Ω probe-to-preamp cable for the Varian system and appropriate changes to the bandwidth (Q) of the NMR probe used on the Bruker spectrometer. Earlier, we reported quite distorted spectra obtained with Varian Unity INOVA spectrometers (at 11.4 and 14.1T) in several exploratory wide bandwidth (14)N MAS NMR studies of inorganic nitrates and amino acids. These spectra have now been compared/evaluated with fully analyzed (14)N MAS spectra correspondingly acquired at 19.6T on a Bruker spectrometer. It is shown that our upgraded version of the STARS simulation/iterative-fitting software is capable of providing identical sets for the molecular spectral parameters and corresponding fits to the experimental spectra, which fully agree with the electronic measurements, despite the highly different appearances for the MAS NMR spectra acquired on the Varian and Bruker spectrometers.     

A compact lensless and slitless volume holographic spectrometer for diffuse source spectroscopy

We present a simple, very compact, and inexpensive spectrometer for diffuse source spectroscopy using only a volume hologram (recorded by two spherical beams) and a CCD camera (or a detector array). We show that this spectrometer can operate well under spatially incoherent light illumination. We also show that the resolution of this spectrometer can be optimized by proper selection of the location of the CCD camera (or the detector array). The results show the possibility of using optimized holographic optical elements as the integrated collimating, dispersive, and light-collective components of spectrometers. PACS 42.40.Pa; 42.79.-e     

卡尔曼滤波ICP－AES法分析稀土元素及其对光谱干扰的校正

本文以卡尔曼（Ｋａｌｍａｎ）滤波ＩＣＰ－ＡＥＳ法进行稀土元素分析，并研究了卡尔曼滤波对其光谱干扰的校正，以及富线基体元素对待测元素、待测元素之间的影响，考察了该方法的检出限、精密度和准确度以及影响滤波的因素。结果表明，该法能有效地消除和校正光谱干扰，减少对分析谱线的选择，改善分析的检出限，分析速度快，结果准确可靠，可适合各种稀土试样（高纯稀土、混合稀土）的日常分析。     

光谱响应对辐射光谱测温法的影响研究

针对光谱响应系数对辐射光谱测温法的影响问题,利用200～1 100和900～1 700 nm两种波段光纤光谱仪测量了不同温度下黑体炉辐射光谱,分析了不同波段高温黑体辐射光谱特征,确定了不同波段光谱分析适宜采用的有效响应波段,获得了不同温度下该波段光谱响应系数变化情况,详细分析了温度对光谱响应系数的影响,总结了辐射光谱法温度拟合时的波长范围以及响应系数选择原则,并分析了波长范围以及响应系数选择对测温的影响,这为提高辐射光谱测温法的测量精度具有重要价值。     

A low-volume cavity ring-down spectrometer for sample-limited applications

In atmospheric and environmental sciences, optical spectrometers are used for the measurements of greenhouse gas mole fractions and the isotopic composition of water vapor or greenhouse gases. The large sample cell volumes (tens of milliliters to several liters) in commercially available spectrometers constrain the usefulness of such instruments for applications that are limited in sample size and/or need to track fast variations in the sample stream. In an effort to make spectrometers more suitable for sample-limited applications, we developed a low-volume analyzer capable of measuring mole fractions of methane and carbon monoxide based on a commercial cavity ring-down spectrometer. The instrument has a small sample cell (9.6 ml) and can selectively be operated at a sample cell pressure of 140, 45, or 20 Torr (effective internal volume of 1.8, 0.57, and 0.25 ml). We present the new sample cell design and the flow path configuration, which are optimized for small sample sizes. To quantify the spectrometer’s usefulness for sample-limited applications, we determine the renewal rate of sample molecules within the low-volume spectrometer. Furthermore, we show that the performance of the low-volume spectrometer matches the performance of the standard commercial analyzers by investigating linearity, precision, and instrumental drift.     

一种快速调节分光计的方法

在分析分光计结构、合理假设基础上,提出了一种快速调节分光计的方法,该方法不但缩短了学生在课堂上调节分光计的时间,而且使学生加深了对分光计结构的理解。     

红外成像光谱测量中Dyson光学系统的研究进展

传统的红外成像光谱仪难以同时实现弱遥感信号下的高信噪比和仪器小型化的要求,基于Dyson同心光学结构的新型遥感红外成像光谱仪具有数值孔径大、信噪比高、结构简单、体积小、重量轻的优点,用于强背景信号下的微弱红外成像光谱信号测量时,可实现传统的红外成像光谱仪难以实现的高信噪比测量。本文概述了Dyson同心光学结构的产生、发展及最新研究动态,重点介绍了Dyson同心光谱仪的原理、研制过程中的难点以及在高性能遥感红外成像光谱测量中的应用,为高性能红外成像光谱仪的研究提供了参考。     

临边成像光谱仪的发展现状与进展

介绍了临边观测模式的探测原理及其特点,给出了美国、欧洲等发达国家关于临边成像光谱仪的研究状况,并列出了各临边成像光谱仪的核心设计方案及具体的技术指标。最后,介绍了国内唯一一例临边成像光谱仪的开展情况,包括设计方案到技术指标。通过对比分析国内外临边成像光谱仪的研究进展,为我国进一步提高临边成像光谱仪的性能及技术指标提供了理论基础。     

Comparison of two confocal micro‐XRF spectrometers with different design aspects

Two different confocal micro X‐ray fluorescence spectrometers have been developed and installed at Osaka City University and the Vienna University of Technology Atominstitut. The Osaka City University system is a high resolution spectrometer operating in air. The Vienna University of Technology Atominstitut spectrometer has a lower spatial resolution but is optimized for light element detection and operates under vacuum condition. The performance of both spectrometers was compared. In order to characterize the spatial resolution, a set of nine specially prepared single element thin film reference samples (500 nm in thickness, Al, Ti, Cr, Fe Ni, Cu, Zr, Mo, and Au) was used. Lower limits of detection were determined using the National Institute of Standards and Technology standard reference material glass standard 1412. A paint layer sample (cultural heritage application) and paint on automotive steel samples were analyzed with both instruments. The depth profile information was acquired by scanning the sample perpendicular to the surface. © 2013 The Authors. X‐Ray Spectrometry published by John Wiley & Sons, Ltd.     

芯片级硅基光谱仪研究进展

光谱仪作为光谱分析不可或缺的工具,在生物传感、食药检测、医疗、环境监测等领域有着广泛的用途。传统的光谱仪体积大、功耗高、价格昂贵和难以二次开发,应用范围受到了极大地限制。随着微型加工工艺的发展,微型化的光谱仪逐渐出现。相较于传统的大型光谱仪,微型光谱仪不仅成本低、体积小、功耗低,而且便于二次开发,扩展了光谱仪的应用范围。但是,微型光谱仪通常是基于分立的光学器件,通过将光学器件的小型化而实现的,集成度和灵活性不高。随着对便携性的要求越来越高,光谱仪的进一步小型化和集成化已成趋势,出现了芯片级的光谱仪。芯片级光谱仪具有明显的尺寸、重量和功耗的优势,将对光谱仪在无人设备、智能平台等新兴领域中的应用产生重要影响。在芯片级光谱仪的实现过程中,硅基光子技术因其成熟的加工工艺和良好的集成性能,为光谱仪的芯片化提供了一种集成化、低成本的解决方案,国内外研究人员针对芯片级硅基光谱仪展开了大量的研究,取得了丰富的成果。文章分析了硅基片上光谱仪的工作原理,将目前的芯片级硅基光谱仪分成了色散型和傅里叶变换型两大类进行介绍,分析了这两类光谱仪的主要特点和典型实现方式。文中给出了刻蚀衍射光栅、波导阵列光栅、多模波导等色散型硅基片上光谱仪和空间外差、驻波式、热调、数字以及基于微机电系统的傅里叶变换型硅基片上光谱仪的最新研究进展,分析了各种光谱仪的性能特点和适用范围。在此基础上,展示了本组的最新研究成果,通过创造性地将基于马赫曾德尔干涉仪的空间外差傅里叶变换型光谱仪结构和波导阵列光栅的色散型光谱仪结构相结合,可同时实现较大的光谱范围和较高的光谱分辨率,为硅基片上光谱仪的应用打下了较好的基础。最后,论述了硅基片上光谱仪的发展趋势与应用前景,为芯片级硅基光谱仪的研究提供了参考。     

基于模块方案分光计调整教学实践简

在综合考虑分光计教学过程基础上，将分光计教学分成实验准备模块、调节方法模块和问题解决模块。模块化教学方式不但缩短了学生在课堂上调节分光计的时间，而且使学生加深了对分光计结构的理解。     

Repeatable intensity calibration of an X-ray photoelectron spectrometer

Ten years ago, NPL developed an infrastructure for calibrating the intensity response functions of electron spectrometers for Auger electron and for X-ray photoelectron spectroscopies. Two software systems were developed: one for Auger electron spectrometers or for Auger electron and X-ray photoelectron spectrometers combined, and one for X-ray photoelectron spectrometers on their own; the latter being applied if no suitable electron gun is available. The system for Auger electron and X-ray photoelectron spectrometers combined has been used regularly to calibrate the Metrology Spectrometer II at NPL and experience shows that this gives an instrumental intensity consistency of 0.4% over 10 years. Evaluations have not previously been reported at this level. The system for Auger electron and X-ray photoelectron spectrometers combined is used here in preference to the system solely for X-ray photoelectron spectrometers since it is more robust to the sample condition and can be used over a wider energy range. These issues, and how observed variations in the instrument intensity response may arise, are explained.     

Efficiency-optimized low-cost TDPAC spectrometer using a versatile routing/coincidence unit

A highly efficient, reliable, and low-cost γ–γ TDPAC spectrometer, PACAr, optimized for ¹⁸¹Hf-implanted low-activity samples, is presented. A versatile EPROM-based routing/coincidence unit was developed and implemented to be use with the memory-card-based multichannel analyzer hosted in a personal computer. The excellent energy resolution and very good overall resolution and efficiency of PACAr are analyzed and compare with advanced and already tested fast–fast and slow–fast PAC spectrometers.     

星载高分辨率超光谱成像仪分光方式的选择

从多个方面分析了棱镜和光栅色散分光的优缺点,分析结果表明棱镜更适于星载高分辨率超光谱成像仪的分光。在透过率方面,棱镜光谱仪透过率高达95.24％(VNIR),而光栅的衍射效率仅为60%~70%。在杂散光方面,棱镜光谱仪的杂散光可达10－4,而光栅的杂散光为10－2。在0.4 －2.5 范围,棱镜光谱仪相对光栅光谱仪有优越性。在色散线性方面,光栅光谱仪基本线性,棱镜光谱仪的短波非线性问题可通过复合棱镜进行补偿。可靠性方面,棱镜光谱仪较光栅光谱仪有优势;在光谱带宽和成本方面,棱镜光谱仪与光栅光谱仪基本接近。     

The influence of polarization and filtration of beams on the ED spectrometers sensitivity

The topic under discussion is the influence of X‐ray polarization and filtration, as well as the influence of detectors count rate on sensitivity and detection limits (DLs) in spectrometers with energy dispersion (EDS). Parameters calculation technique for searching optimal analysis conditions has been developed. Typical DLs of elements with medium and high atomic numbers on various spectrometers are given (on wave dispersive spectrometers (WDS), energy dispersive spectrometers (EDS) without polarization and energy‐dispersive polarized‐beam X‐ray spectrometers (EDPXRS). Apparently, EDS variants are preferred for determining elements with Z > 62–65, and EDPXRS spectrometers with concave targets and increased aperture are preferred for determining elements with medium atomic numbers.     

成像光谱仪同心光学系统的研究

介绍了Offner凸面光栅成像光谱仪和Dyson凹面光栅成像光谱仪两种常用的同心光学系统。Offner凸面光栅成像光谱仪采用全反射的形式,使用光谱范围很宽,加工、装调较为简单,受外界环境影响较小;Dyson凹面光栅成像光谱仪在体积和尺寸上的优势较为明显,易于实现整体结构的小型化。给出了这两种成像光谱仪的具体设计实例,两种光学系统的成像质量均能达到较为理想的结果,其结构畸变均＜0005%,在使用光谱范围内,光谱分辨率均能到达3 nm,具有高质量的光学传递函数。最后,给出了配合成像光谱仪使用的多种前置光学系统的结构形式,并讨论了消除系统杂散光的方法及消除光谱级次重叠的方法。     

Stimulated acceleration and confinement of deuterons in focuseddischarges. I

Acceleration and confinement of megaelectronvolt D⁺ ions in the plasma focus (PF) are analyzed in terms of the observed energy spectrum of the ejected ions and of the energy spectrum of the D-D neutrons from which the trapped-ion spectrum is derived. The current distribution in the interelectrode gap can be modified by field distortion elements (FDEs) which increase the fraction of total electrode current flowing in the pinch. An optimized FDE increases the observed maximum value and the mean value of the observed D-D neutron yield per shot by a factor ⩾3. The ejected-ion spectrum is determined by three independent methods (Thomson spectrometers, high-resolution magnetic analyzer, filters, and Faraday cups)     

Effect of the size of experimental channels of the lead slowing-down spectrometer SVZ-100 (Institute for Nuclear Research, Moscow) on the moderation constant

Lead slowing-down (LSD) spectrometers have a low energy resolution (about 30%), but their luminosity is 10³ to 10⁴ times higher than that of time-of-flight (TOF) spectrometers. A high luminosity of LSD spectrometers makes it possible to use them to measure neutron cross section for samples of mass about several micrograms. These features specify a niche for the application of LSD spectrometers in measuring neutron cross sections for elements hardly available in macroscopic amounts—in particular, for actinides. A mathematical simulation of the parameters of SVZ-100 LSD spectrometer of the Institute for Nuclear Research (INR, Moscow) is performed in the present study on the basis of the MCNPX code. It is found that the moderation constant, which is the main parameter of LSD spectrometers, is highly sensitive to the size and shape of detecting volumes in calculations and, hence, to the real size of experimental channels of the LSD spectrometer.     

Wavenumber Calibration of CCD Detector Raman Spectrometers Controlled by a Sinus Arm Drive

Abstract

The calibration procedures needed for use of dispersive Raman spectrometers have been reviewed. Like other high‐precision spectrometers incorporating moving gratings, Raman spectrometers are subject to problems with wavenumber scale accuracy. Commercially available Raman spectrometers of types DILOR‐HORIBA LabRam and RENISHAW System 1000 have been examined for wavenumber scale stability, linearity, and reproducibility. For reliable use of the wavenumber data, daily calibration is a necessity. A procedure to examine the linearity of such mechanical drive systems is presented. A new finding was that the examined spectrometers give wavenumber calibration errors that were quite reproducible from day to day at a given temperature in the laboratory but depended markedly on the selected setting of the gratings. Knowledge of this linearity problem is essential for obtaining a reliable calibration. The most correct calibration was obtained by the use of certain “golden” settings of the sinus drive at a constant temperature of the laboratory. In this way, the examined spectrometers could be used with better precision, without daily calibration, provided the temperature of the room was constant or corrected for. A procedure for correction of these errors by the software is suggested.