红外探测器光谱响应率定标方法

采用新的方法对波长范围1-3μm的红外探测器绝对光谱响应率进行定标.红外探测器的光谱响应率定标是在两套定标系统上利用两种参考探测器实现的.首先在红外光谱比较系统上利用一个平响应的腔式热电堆探测器作为参考探测器,测量待测红外探测器相对于标准探测器的连续光谱响应率;然后在可见一近红外定标系统上,利用低温辐射计和激光器在几个单立波长上进行绝对光谱响应率测量.这样,通过计算就能得出待测红外探测器在每个波长上的绝对光谱响应率.采用上述方法对TS-76探测器进行光谱响应率定标,联合不确定度小于0.95%.     

通道式辐射计的相对光谱响应率定标

为配合气象卫星的在轨辐射定标,利用自行设计的宽光谱辐射定标系统配合高精度陷阱探测器,采用光谱替代法为试验中所需的可见、近红外辐射计和近红外、短波红外辐射计进行了高精度相对光谱响应率定标.详细叙述和分析了定标过程以及影响测量结果的不确定度源,其最终合成不确定度为3.21×10-3,满足了定标精度要求.     

NPL改进的光谱响应标准（400nm～20μm）（二）

（上接1998年第18卷第5期第42页）21～20um红外光谱响应率标准红外光谱响应率标准是通过两台对应两种类型的主标准探测器建立起来的。连续的相对光谱响应标准由一个响应率无波长选择性的空腔型热释电探测器建立起来的。绝对光谱响应率标难是通过使用激光辐射和一个热电堆辐射计作传递标准，同NPL基本标准低温辐射计绝对光谱响应率点进行比较得到的。空腔热释电探测器剖面图如图3所示。它由一个大面积（lmm直径）涂黑的热释电探测器装在一个25mm直径的半球型反射腔中间构成。Gillham使用相似的探测器进行了实验，Day等分析了其特性。加上反…     

关于新的光电探测器光谱响应度工作标准的研究

本文介绍了新的光电探测器光谱响应度工作标准 ,该项标准参加了 2 0 0 0年CCPR(国际计量委员会所属光度和辐射咨询委员会 )组织的国际比对。在新的工作标准中 ,用调制光代替原来的直流光 ,以减少杂散光、噪声等对测量准确度的影响 ;用锥腔型热释电探测器代替原来的热电堆探测器作为参考探测器 ,用锁相测量仪器代替原来的直流测量仪器并增加温度控制 ,以便提高测量系统的灵敏度和光谱响应度标准的平坦程度 ,进而提高准确度 ;以双单色仪代替原来的单色仪 ,大大减少杂散光 ;同时增加了光谱响应度的绝对定标     

CMOS兼容的微机械P/N多晶硅热电堆红外探测器

提出一种采用正面开口进行湿法腐蚀释放热电堆的结构,通过利用高精度光刻、LPCVD(low -pressure chemical vapor deposition)薄膜生长、IBE(ion beam etching)干法刻蚀、TMAH ((CH3)4NOH)腐蚀等微机械加工技术,设计并制作了CMOS兼容的微机械多晶硅热电堆红外探测器.实验得到的器件成品率达到90%以上,响应率为12.5 V/W,探测率1×107 cmHz1/2/W,为进一步大规模红外面阵研究奠定了基础.     

采用单片式探测器实现辐射通量定标

在基于双单色仪的辐射通量定标中,为了克服陷阱探测器视场小、孔径小的缺点,提出了采用单片式探测器替代陷阱探测器进行辐射通量定标的方法。采用只与光路垂直的一片硅探测器,使其光敏面与孔径光阑几乎重合,以增大探测器的孔径角。同时为了保证测量精度,采用偏置电流极低的运算放大器OPA128,并且增大了反馈电阻,以增强对弱信号的响应。采用单片式探测器对400—1000nm波长范围内进行辐射通量定标,系统不确定度包括：探测器响应拟合不确定度7‰,从陷阱探测器到单片探测器的传递不确定度3．14‰,光源波动小于1‰,系统重复性的不确定度3‰,最终合成不确定度为8．3‰,测量结果满足要求。     

光电探测器相对光谱响应度标准

本文介绍光电探测器相对光谱响应度标准的实验装置、方法及测量结果。该装置以补偿型真空热电堆为参考基准,采用双光路替代法,全部测量过程自动化。总的不确定度为±(1.5～4.0)％。     

基于相关光子的光电探测器量子效率定标研究

介绍了一种新型的辐射定标方法,利用二极管泵浦的、倍频的固体钛宝石连续激光器倍频后产生的351mn紫外激光抽运非线性BBO晶体,定标了光电倍增管在633 nm、702 Bin和789 nm的量子效率,介绍了测量原理和实验装置,观察到符合峰现象,分析了触发通道滤光片的带宽、探测器的位置校准、以及探测器死时间对测量结果的影响,最后分析了这种定标方法的不确定度,定标结果的相对合成不确定度低于5.8%.这种方法可以发展成为一种高精度的新型辐射定标方法.     

400～1700 nm绝对光谱响应度校准和量值传递

介绍了高准确度光辐射功率校准原理和方法,利用低温辐射计作为主标准器,以陷阱探测器作为传递标准,激光器作为光源,通过激光功率稳定装置,校准了硅陷阱探测器和铟镓砷陷阱探测器的绝对光谱响应度。选取476.1, 488, 514.7, 521, 568, 632.8, 647.1, 785, 852, 980, 1064, 1550,nm共12条谱线完成了校准实验,绝对光谱响应度测量不确定度均优于0.05%。通过量子效率模型得出了硅陷阱探测器的绝对光谱响应曲线。利用InGaAs陷阱探测器分立波长点的绝对光谱响应度与相对光谱响应曲线进行了验证分析。结果表明,2种陷阱探测器均可用作传递标准进行高准确度的可见光和近红外光辐射功率校准和量值传递。     

200～400nm波段光电探测器光谱响应度测量装置研究

本文叙述了200~400nm波段光电探测器光谱响应度的测量装置原理、测量系统及不确定度。采用紫外光谱强度大的氙灯作为光源,采用紫外分光效率高的单色仪进行分光,腔型热释电探测器与标准硅光电探测器进行相对光谱响应比较得到标准硅光电探测器相对光谱响应度。绝对值标定则是利用低温辐射计对无窗紫敏硅光电探测器进行测量后再传递到标准硅光电探测器,从而最终测量出标准硅光电探测器在紫外波段的绝对光谱响应度。     

Low-cost satellite attitude control sensors based on integratedinfrared detector arrays

This paper describes attitude control systems (ACS) for satellites and a new, static system based on an integrated infrared (IR) detector array. After a short introduction on the use and control of satellites in general, we explain the advantage of static systems, made possible by the use of integrated IR detector arrays. In particular, the static system is lighter and smaller than the previous systems, and requires less power. The electronics is updated to state-of-the art, increasing the autonomy of the system and thereby reducing its dependence upon the satellite microcontroller. The detectors are based on a bipolar silicon process for the mechanical structure (using electrochemically controlled etching-KOH etching), with an SiN membrane for thermal isolation of the pixels, which have a polymer black coating for transduction of radiation to heat and n-type versus p-type polysilicon thermopiles for heat detection. The pixel pitch is 600 μm, the black area is approximately 495 × 440 μm², and the pixel sensitivity is approximately 55 V/W, at a thermopile resistance of 23 kΩ. Two types of detectors have been designed: a single-array type with 32 pixels in two staggered arrays, and a chip with four 32-pixel arrays integrated in a cross. This has made it possible to make a family of earth sensors for the different missions in space     

Best Practice Guidelines for Pre-Launch Characterization and Calibration of Instruments for Passive Optical Remote Sensing

The pre-launch characterization and calibration of remote sensing instruments should be planned and carried out in conjunction with their design and development to meet the mission requirements. The onboard calibrators such as blackbodies and the sensors such as spectral radiometers should be characterized and calibrated using SI traceable standards. In the case of earth remote sensing, this allows inter-comparison and intercalibration of different sensors in space to create global time series of climate records of high accuracy where some inevitable data gaps can be easily bridged. The recommended best practice guidelines for this pre-launch effort is presented based on experience gained at National Institute of Standards and Technology (NIST), National Aeronautics and Space Administration (NASA) and National Oceanic and Atmospheric Administration (NOAA) programs over the past two decades. The currently available radiometric standards and calibration facilities at NIST serving the remote sensing community are described. Examples of best practice calibrations and intercomparisons to build SI (international System of Units) traceable uncertainty budget in the instrumentation used for preflight satellite sensor calibration and validation are presented.     

大气垂直探测仪光谱定标

为了大气垂直探测仪能够进行精确的光谱测量,对其进行光谱定标.大气垂直探测仪使用面阵探测器,由于离轴像元接收的光线不平行于光轴,使仪器函数发生变化.本文针对大气垂直探测仪使用的16x4元面阵探测器理论分析给出仪器函数,讨论其对光谱定标的影响,并将利用理论分析结果及利用气体吸法测得的光谱,对大气垂直探测仪进行了光谱标定,光谱定标精度达10-5.采用面阵探测器的干涉仪,边缘视场像元所测光谱会向低频漂移,因此必需研究干涉仪的仪器函数,从而消除光谱漂移对边缘视场光谱定标的影响.     

模态分析在辐射制冷器设计中的应用

辐射制冷器主要为红外探测器提供合适的低温工作条件,是星载红外遥感探测系统的重要组成部分,其可靠性的高低和制冷性能的好坏将直接影响红外成像质量和遥感卫星的成败.建立了W型辐射制冷器结构的有限元模型,应用MSC/Nastran软件完成了模态、静力、正弦振动响应计算,进行了结构强度和振动模态分析,预示和验证了辐射制冷器的结构性能,为其结构设计改进提供了可靠理论依据.     

空间机械制冷机与红外探测器的耦合技术

在空间红外遥感中，红外探测器是通过与制冷机的耦合获取冷量的。着重讨论为满足红外探测的需要，如何最大限度地消除空间的振动、电磁干扰等不利因素的影响。同时介绍降低漏热，提高冷量传输效率，从而保证制冷机与红外探测器良好耦合的技术。     

Vacuum Radiance-Temperature Standard Facility for Infrared Remote Sensing at NIM

As infrared remote sensors are very important parts of Earth observation satellites, they must be calibrated based on the radiance temperature of a blackbody in a vacuum chamber prior to launch. The uncertainty of such temperature is thus an essential component of the sensors’ uncertainty. This paper describes the vacuum radiance-temperature standard facility (VRTSF) at the National Institute of Metrology of China, which will serve to calibrate infrared remote sensors on Chinese meteorological satellites. The VRTSF can be used to calibrate vacuum blackbody radiance temperature, including those used to calibrate infrared remote sensors. The components of the VRTSF are described in this paper, including the VMTBB, the LNBB, the FTIR spectrometer, the reduced-background optical system, the vacuum chamber used to calibrate customers’ blackbody, the vacuum-pumping system and the liquid-nitrogen-support system. The experimental methods and results are expounded. The uncertainty of the radiance temperature of VMTBB is 0.026 °C at 30 °C over 10 μm.     

Blackbody calibration sources of high accuracy for a spaceborne infrared instrument: the Along Track Scanning Radiometer

We describe the two 140-mm-aperture simulated blackbody sources used for the on-board calibration of the Along Track Scanning Radiometer, a spaceborne thermal infrared instrument for the accurate remote sensing of sea surface temperature, in operation since 1991. The design of these spaceborne sources, which operate at ≈ -10 °C and ≈ +30 °C, allows them to meet their unprecedented accuracy goal, namely a 3σ uncertainty in their brightness temperature of <0.1 K for the whole mission. This performance is empirically demonstrated in the laboratory and in flight by long-term temperature readout tests, temperature uniformity measurements, and direct emissivity measurements.     

Properties of Indium Antimonide Detectors for use as Transfer Standards for Detector Calibrations

The properties of 4-mm-diameter and 7-mm-diameter liquid-nitrogen-cooled indium antimonide detectors were investigated to determine their suitability as transfer standards (i.e., reference detectors) for the detector calibration facility at the National Research Council of Canada. The spectral responsivity of the InSb detectors in the spectral range 1000-3000 nm was determined by atwo-step procedure involving the use of germanium transfer standardsand suitably characterized thermopiles. It is shown that thelong-term reproducibility of the InSb detector calibrations is approximately ?1%. The uniformity and linearity as a function of wavelength, as well as the background current noise and drift of thetwo detectors, are compared. It is shown that the 7-mm-diameter detector is clearly superior to the 4-mm one for use as a transfer standard. It is estimated that the overall accuracy of the calibrations of the two InSb detectors is ?2% in the range 1200-2800 nm.     

面源红外定标黑体控温热分析

红外定标黑体是红外遥感探测器进行红外定标试验的关键设备,黑体的温度控制精度和温度均匀性是定标黑体能否满足试验需求的关键。针对某设备所采用黑体的独特结构和液氮制冷控温结构进行了热分析,证明所采用的控温结构和方法能够满足黑体控温要求。     

Traceable laser power measurements of diode laser radiation in the near infrared

We report a new calibration setup for laser radiometry at the Physikalisch-Technische Bundesanstalt, the German National Metrology Institute. Measurements of laser diode power of free beam diode lasers in the near infrared spectral range at a wavelength of 808 nm for powers up to 250 W and at wavelengths of 915 nm, 940 nm, and 980 nm for laser powers up to 25 W have been established. The calibration setup, the standard detector, the uncertainty budget and first calibration results will be presented and discussed. The standard uncertainty of the HLR302 standard detector is 0.2%. This uncertainty might be the main contribution to the overall uncertainty in customer calibrations, depending on the quality of the transfer detectors.