关于光学速调管长波长辐射的分析

由波荡器渡越辐射公式和电子通过wiggler边界产生的长波长辐射公式, 解析给出了电子通过光学速调管时产生的长波长辐射公式. 根据基本的电动力学公式数值计算出合肥同步辐射装置光学速调管的长波辐射, 并将其结果与解析公式的结果进行比较. 计算合肥同步辐射装置的光学速调管和弯转磁铁在红外波段范围内辐射的强度和通量, 表明光学速调管有很好的性能.本文说明, 光学速调管不但可以用来进行相干谐波的试验研究, 也可以兼用作储存环中的红外辐射光源.     

A new optical scheme for large‐extraction small‐aberration vacuum‐ultraviolet synchrotron radiation beamlines

Vacuum‐ultraviolet radiation delivered by bending‐magnet sources is used at numerous synchrotron radiation facilities worldwide. As bending‐magnet radiation is inherently much less collimated compared with undulator sources, the generation of high‐quality intense bending‐magnet vacuum‐ultraviolet photon beams is extremely demanding in terms of the optical layout due to the necessary larger collection apertures. In this article, an optimized optical layout which takes into account both the optical and electron beam properties is proposed. This layout delivers an improved beam emittance of over one order of magnitude compared with existing vacuum‐ultraviolet bending‐magnet beamlines that, up to now, do not take into account electron beam effects. The arrangement is made of two dedicated mirrors, a cylindrical and a cone‐shaped one, that focus independently both the horizontal and the vertical emission of a bending‐magnet source, respectively, and has been already successfully applied in the construction of the infrared beamline at the Brazilian synchrotron. Using this scheme, two vacuum‐ultraviolet beamline designs based on a SOLEIL synchrotron bending‐magnet source are proposed and analysed. They would be useful for future upgrades to the DISCO beamline at SOLEIL and could be readily implemented at other synchrotron radiation facilities.     

光弹材料载荷过程中红外辐射特征机理的计算分析

基于材料的热力学关系和能量守恒定律,给出弹性体形变过程中红外辐射温度改变量和辐出度变化的物理计算方程.并结合有限元方法进行物理建模,对光弹材料三点弯载荷实验过程中的红外辐射出射度的分布进行数值计算和模拟.结果与实验结果吻合较好,表明模型及其相关理论是合理的,可以用来量化揭示实验中的红外辐射特征.从而得到一种能够利用计算机量化分析固体材料载荷过程中红外辐射特征机理的计算方法.     

Performance of the infrared microspectroscopy station at SSRF

At the third generation synchrotron light source Shanghai Synchrotron Radiation Facility (SSRF), the first infrared beamline BL01B has been successfully constructed. The infrared beamline collects both bending magnet and edge radiation. A brief introduction of the infrared beamline design has been given in this article. The infrared microspectroscopy station is equipped with a Nicolet 6700 FTIR spectrometer and a Nicolet Continuum Microscope. The flux at the entrance of the FTIR spectrometer, the intensity profile, the signal to noise ratio (SNR) with different apertures, and the focused spot size of the infrared microspectroscopy station have been measured. The performances with synchrotron radiation infrared source and internal globar source have been compared. The results indicate that the infrared microspectroscopy station at SSRF has the ability of analysis samples in a small area with diffraction limited spatial resolution.     

Special-purpose radiation sources based on the Siberia-2 storage ring

Synchrotron radiation (SR) generated by homogeneous magnetic fields of bending magnets is now employed at the Siberia-2 electron storage ring. It is planned that, in the near future, most of the storage ring’s free straight sections will be equipped with insertion devices (undulators and wigglers). Two projects of specialized radiation sources based on the Siberia-2 stor age ring are discussed. The first source is a vacuum milliundulator intended for generation of extremely bright X-ray beams. An X-ray source with vertically limited diffraction is shown to be feasible when the vertical emittance of an electron beam is equal to the diffraction emittance of photons with an energy of 2 keV. The second source uses edge radiation (ER) generated at the ends of bending magnets of the storage ring. Calculations show that, in the infrared and ultraviolet spectral regions, the ER intensity must exceed the intensity of standard SR formed by the homogeneous field of a bending magnet.     

关于wiggler长波自发辐射的理论分析与数值计算

电子通过wiggler产生的辐射，除了短波辐射在轴线附近也有较强的长波辐射，在与轴线夹 角1/γ处达到最大.推导出wiggler长波辐射公式，理论分析了这种辐射的特点，并且将 理论分析的结果与数值计算的结果进行了比较.对在红外波长范围内电子束通过弯转磁铁和wiggler时产生的辐射强度和光通量作了计算，结果表明wiggler下的辐射强度和光通量均强 于弯转磁铁.比较了弯转磁铁的边沿辐射、波荡器的渡越辐射和wiggler长波辐射，表明wigg ler在红外波长范围辐射的性能最优. 关键词： wiggler 波荡器 弯转磁铁 长波辐射     

纳秒激光诱导空气等离子体的红外辐射特性研究

纳秒激光诱导空气等离子体存在从紫外、可见、近红外乃至射频微波的宽谱段辐射,但目前的研究大多关注紫外到可见波段的光谱辐射。激光等离子体作为一种新型的红外辐射源具有很多优势,相比于红外干扰弹以及红外干扰手段而言,空气等离子体红外辐射源可以灵活布置,成本低廉,因此研究空气等离子体的红外辐射特性就很有必要。针对目前脉冲激光诱导空气等离子体的红外干扰研究需要,对激光波长为532 nm的纳秒脉冲激光诱导空气等离子体的红外辐射特性进行实验研究,探讨激光能量对空气等离子体红外辐射强度的影响规律,以及空气等离子体红外辐射的角度分布特性,分析了等离子体红外辐射的可能产生机制。实验结果表明,激光诱导空气等离子体在950～1 700 nm范围内的红外光谱为线状谱和连续谱的叠加。其中线状谱主要是氮和氧的中性原子谱线,并且氮原子红外辐射占主导。随着激光能量的增加,由于空气击穿产生的氧和氮原子数量增加,导致空气等离子体红外辐射的谱线强度逐渐增大。随着红外探测角度的变化,在探测角度为75°时,OⅠ 1 128.63 nm和NⅠ1 246.96和1 362.42 nm谱线强度达到最大,在探测角度为120°时,NⅠ 1 011.46和1 053.96 nm谱线强度达到最大,这是因为空气等离子体红外辐射强度随探测角度变化呈现空间非对称性,表明空气等离子体内不同粒子的空间分布呈现非对称性。     

复杂海洋环境下目标的红外辐射特征分析研究

分析研究了复杂海洋环境下点目标的红外辐射特征,从红外警戒探测系统应用的角度出发,给出了海洋环境下迎面攻击目标的红外辐射特征模型的建立、计算与分析方法。利用大气透过率计算软件计算并分析了特定条件下三个海域的目标红外辐射的大气透过率。给出了迎头攻击目标红外辐射特征的简化计算模型,并分析了特定区域下目标的红外辐射特征。     

化学反应机理对液氧煤油发动机尾焰红外特性影响研究

提出了一种液氧煤油发动机尾焰红外辐射特性计算方法,首先采用计算流体力学软件对液氧煤油发动机内流场进行计算,然后以获得喷管喉部截面参数作为入口边界条件计算发动机尾焰流场,最后以发动机尾焰流场参数分布为基础,采用有限体积法对发动机尾焰红外光谱辐射特性和成像特性进行计算,并对比验证了模型和方法的准确性。在此基础上,研究了化学反应机理和复燃反应过程对尾焰红外辐射特性影响。结果表明,采用多步化学反应能够准确模拟液氧煤油发动机内流场,温度相比热力学计算大3.34%,压力相比试车测量大2.89%;考虑复燃反应使尾焰红外辐射强度增强显著,在采用单步化学反应和多步化学反应两种工况下2~5波段红外辐射强度分别增大50%~100%和150%~170%,但不会影响尾焰红外光谱辐射特性和红外总辐射强度随探测角变化趋势;采用单步化学反应和多步化学反应都能够获得清晰结构的红外成像图像,但是前者2~5尾焰红外辐射强度要比后者增大90%~190%,且两种工况下发动机尾焰红外光谱辐射特性差别很大,尾焰红外总辐射强度随探测角变化趋势也不同。     

红外诱饵的辐射特性及在光电对抗系统中的作用

介绍了红外诱饵的辐射特性及在光电对抗系统中的作用，给出两类诱饵的光谱辐射特性曲线、光谱辐射数据表、红外热辐射特征、时域变化特性曲线等，指出诱饵弹的发展趋势。     

隐身飞机尾焰的红外辐射特性

隐身飞机尾焰的红外辐射是隐身飞机探测的主要辐射源.本文提出了一种新的隐身飞机尾焰红外辐射特性计算模型.该模型以普通飞机尾焰红外辐射特性计算模型为基础,进而考虑红外隐身措施的影响,间接实现隐身飞机尾焰的红外辐射特性的计算.计算模型分别考虑了隐身飞机的二元喷口、引射技术、红外遮蔽云以及遮挡对尾焰辐射的影响.计算结果得出,添加隐身措施后尾焰辐射强度仅为添加前辐射强度的5.8%.针对隐身飞机尾焰红外辐射特性很难获取的问题,将计算结果与喷灯燃烧航空煤油的光谱峰位数据进行了比较,实验结果显示隐身前后辐射能量量级变化与国外文献相同,表明该模型可以用于隐身飞机尾焰红外辐射特性计算.     

坦克炮身管温度分布及红外辐射特性

对具有太阳辐射及受射击过程影响的坦克炮身管建立了温度及其红外辐射特性理论模型，并对以下三种情况进行了计算：坦克炮身管在太阳辐射一段时间后单发射击、太阳照射一段时间后多发慢速射击及太阳照射一段时间后多发射击。本文还分析讨论了各种情况下坦克炮身管外表面温度的变化规律及其对红外辐射特性的影响，对坦克整体红外辐射特性的研究具有重要意义。     

Optimized IR synchrotron beamline design

Synchrotron infrared beamlines are powerful tools on which to perform spectroscopy on microscopic length scales but require working with large bending‐magnet source apertures in order to provide intense photon beams to the experiments. Many infrared beamlines use a single toroidal‐shaped mirror to focus the source emission which generates, for large apertures, beams with significant geometrical aberrations resulting from the shape of the source and the beamline optics. In this paper, an optical layout optimized for synchrotron infrared beamlines, that removes almost totally the geometrical aberrations of the source, is presented and analyzed. This layout is already operational on the IR beamline of the Brazilian synchrotron. An infrared beamline design based on a SOLEIL bending‐magnet source is given as an example, which could be useful for future IR beamline improvements at this facility.     

真空条件下低温红外辐射测量技术研究

针对红外载荷在轨服役期间低温目标的红外辐射探测需求,提出一种真空条件下的低温红外辐射测量方案,并研制了测量装置。测量装置主要由低温红外光学系统、低温机械结构、低温红外探测系统及微弱信号处理系统构成。低温红外辐射经过光学系统会聚到探测器像面,锁相放大器利用相干检测技术将目标信号提取,完成低温红外辐射的测量。测量装置研制完成后,在真空仓内使用标准黑体辐射源,在198 K～423 K温度范围内进行了低温红外辐射定标试验,取得了有效的试验数据,测量不确定度在5%以内。该文提出的真空条件下低温红外辐射测量技术可为在轨空间红外载荷低温红外目标探测设计提供重要数据支撑。     

Comparison between the Results of Simulating the Synchrotron Radiation from a Bending Magnet and Experimental Data

The results of using two (SPECTRA and SRW) programs for simulating synchrotron radiation (SR) are presented. Calculations are performed for coherent SR from a beam of electrons with moderately relativistic energies in a short bending magnet. Simulation is carried out for real beam parameters. A comparison between simulation and experimental data indicates their good agreement. Both general information for the given codes grouped by a number of criteria and specific data on simulating radiation from bending magnets are presented.     

Synchrotron-based multiple-beam FTIR chemical imaging of a multi-layered polymer in transmission and reflection: towards cultural heritage applications

IRENI (infrared environmental imaging) is a recently commissioned Fourier transform infrared (FTIR) chemical imaging beamline at the Synchrotron Radiation Center in Madison, WI, USA. This novel beamline extracts 320 mrad of radiation, horizontally, from one bending magnet. The optical transport separates and recombines the beam into 12 parallel collimated beams to illuminate a commercial FTIR microspectrometer (Bruker Hyperion 3000) equipped with a focal plane array detector where single pixels in the detector image a projected sample area of either 0.54×0.54 μm² or 2×2 μm², depending in the measurement geometry. The 12 beams are partially overlapped and defocused, similar to wide-field microscopy, homogeneously illuminating a relatively large sample area compared to single-beam arrangements. Both transmission and reflection geometries are used to examine a model cross section from a layered polymer material. The compromises for sample preparation and measurement strategies are discussed, and the chemical composition and spatial definition of the layers are distinguished in chemical images generated from data sets. Deconvolution methods that may allow more detailed data analysis are also discussed.     

Frequency conversion of broadband laser radiation distorted by spherical aberration in uniaxial crystals

Mechanisms of the frequency conversion of broadband infrared laser radiation in a uniaxial crystal with the radiation focused by a lens with spherical aberration are investigated. A mathematical model is presented. Computer modeling of the spatial–angular structures of frequency-converted focused broadband infrared radiation is performed.     

基于图像的飞行器红外辐射特性测量

通过将目标在一定波段内的红外辐射等效为红外成像系统前一定距离下黑体在对应波段内的红外辐射,建立了等效辐射方程。根据黑体辐射定标实验数据,利用非线性回归方法确定了在不同的积分时间条件下红外凝视成像系统输出红外图像的灰度值与在一定距离下的黑体温度之间的定量关系,建立了辐射定标方程。在Visual C++6.0平台下,在对红外目标图像进行SUSAN滤波等预处理后,分析了已知目标距离的红外图像的灰度均值。首先根据辐射定标方程计算出目标等效为黑体的温度,然后利用等效辐射方程反推目标的红外辐射强度,以达到根据跟踪的红外图像确定红外目标辐射特性的目的。此项研究不仅可以为目标识别提供目标分类、识别和辨认所必需的光谱数据库,而且还可以为红外预警提供重要的参考数据。     

Infrared imaging characteristics of space-based targets based on bidirectional reflection distribution function

A modeling method of infrared imaging characteristics of a space-based target was presented. Background radiation environment of a space-based target was analyzed and the background radiation mainly consists of direct radiation of the sun, thermal radiation and reflected radiation of the earth. The target surface was divided into regions based on geometrical shape and surface material characteristics and a surface equation of each region was built based on its body coordinate system. Each region was divided into meshes supposing that each mesh is a micro-plane. A bidirectional reflection distribution function (BRDF) model considering the characteristics of surface Gauss statistics and self-shadow was introduced to describe reflected infrared of each mesh of the target surface. The emitted infrared radiation of each mesh of the target surface was described according to its thermal equilibrium temperature. Then a mathematical model on infrared radiation imaging characteristics of the space-based target was built in terms of the given infrared detector. The relative positions of the space-based target, the background radiation sources and the detector are determined by orbital parameters based on coordinate conversion. Visual surfaces of the target to observation system were determined by vector coordinate method. Simulation of optical imaging characteristics of the target in orbit was achieved according to its given geometrical dimensions and physical parameters. The results show the method is feasible and robust for infrared characteristics of the space-based target when single reflection is considered and its surface is regular and can be described in a surface equation. It can provide a facility to real-time analysis of infrared imaging characteristics of the space-based targets.     

硅微机械悬臂梁红外辐射热探测技术的研究

研究了利用镀膜硅微机械悬臂梁红外辐射热挠曲实现红外辐射探测的技术,建立了镀膜双层硅微悬臂梁红外辐射热挠曲的理论模型.并利用镀有二氧化硅膜层的硅微悬臂梁,在硅微悬臂梁根部制作热挠曲检测压敏电阻,用实验方法测试了硅微悬臂梁对红外辐射的响应规律,结果表明该镀膜硅微悬臂梁对顶端辐射激励的1.5 μm红外光的响应灵敏度可达 2.39 μV/mW.用计算机优化方法得到了硅微机械悬臂梁的最佳镀膜厚度比的规律,为进一步提高硅微悬臂梁红外探测的灵敏度提供了设计依据.