NIM和VNIIOFI光谱辐射照度双边比对

2014年12月至2015年1月,中国计量科学研究院(NIM)采用新研制的光谱辐射照度国家基准装置,与全俄光物理测量研究院(VNIIOFI)进行了光谱辐射照度双边比对。比对的波长范围为250～2500nm, NIM和VNIIOFI的光谱辐射照度测量均基于高温黑体辐射源BB3500M,采用高温计测量黑体的温度,溯源至Pt-C和Re-C固定点黑体,并采用WC-C固定点黑体进行了验证,双方在3021K的温度一致性优于70mK。光谱辐射照度双边比对结果表明: 44个比对波长点的光谱辐射照度的平均相对偏差为0.45%。除2000nm波长点的相对偏差为1.1%外,在全波段范围内量值的一致性优于0.90%,均在声称的不确定度范围内。     

第四代光谱辐射度和色温度国家基准装置的研制

基于高温黑体辐射源BB3500M研究并建立了第四代光谱辐射度和色温度国家基准装置。采用稳流和稳温相结合的反馈工作模式,开启后3 h即达到温度稳定。3 016 K时,1 h内的温度变化小于0.59 K。温度测量直接溯源至Pt-C和Re-C高温共晶点黑体,2 980 K时的测量不确定度为0.64 K(k=1)。光谱辐射亮度和光谱辐射照度的波长范围向短波分别扩展至220 nm、230 nm,长波扩展至2 550 nm,达到全波段光谱辐射亮度CCPR-S1比对的能力。新基准增加了分布温度参数的测量能力,2 353 K和2 856 K的测量不确定度(k=1)分别改善为1.6 K和2.1 K。对基准装置入射光学系统的辐照不均匀性以及短波紫外大气传输过程所带来的散射和吸收进行了数值计算,提出理论修正方法,将辐照不均匀性测量误差减小0.3%,大气传输误差减小0.29%。     

光谱辐射亮度和光谱辐射照度国家基准

光谱辐射亮度和光谱辐射照度的量值是根据普朗克定律建立的。当绝对黑体的温度被准确测量，其光谱辐射亮度和光谱辐射照度可通过普朗克公式算出。中国计量科学研究院建立的光谱辐射亮度和光谱辐射照度基准装置由高温黑体、光电高温计和自动光谱辐射计组成。通过替代比较方法将量值过渡到副基准灯组、工作标准灯，实现量值的保存和传递。1986年经原国家技术监督局批准为国家基准。基准的技术指标高温黑体工作温度：2000K－3000K光谱发射系数：0，997温度均匀性黑体腔内：10K温度稳定性：0．SK／h温度测量不确定度：4K（k＝l）工作波长：25…     

900 nm照度辐射温度计的研制

介绍了中国计量科学研究院基于黑体辐射原理研制的波长为900 nm、测温范围为600～1 500 ℃的照度辐射温度计。该辐射温度计测量探测器接收的光谱辐射照度,采用单点分度法,结合有效波长测量技术,直接依据普朗克辐射定律计算被测温度,具有结构简单、测温稳定性好的特点。单点分度法以Cu点为固定点在Al点测温偏差为-0.04 ℃,而在800 ℃和900 ℃两个点,与RT9032辐射温度计测量结果偏差分别为0.09 ℃和0.11 ℃。     

基于激光积分球反射计的集成黑体发射率测量研究

集成黑体发射率是评价其有效光谱辐射亮度不确定度的关键贡献项。建立了激光积分球反射计测量系统,对中国计量科学研究院制备的集成空腔的法向光谱发射率进行了实验研究和模拟验证。在633nm的波长下测量了集成黑体法向光谱发射率,测量结果的标准不确定度优于0.043%。结果表明:集成黑体辐射源在室温条件下的有效发射率高于0.998,与STEEP3蒙特卡罗模拟计算结果偏差在0.04%之内。实验结果与数值模拟的一致性在测量结果不确定度内吻合良好,验证了激光积分球发射计法用于评价集成黑体发射率的可行性。     

用等离子体辐射源建立紫外光谱辐亮度副基准(200nm～350nm)

在远紫外和真空紫外光谱区，我国已有的光谱辐射基准源一高温黑体没有足够高的辐射强度和足够灵敏的辐射响应度，不能作这个光谱区的辐射基准。短波辐射强、稳定而可重复的壁稳氮弧等离子体，可作为这个光谱区的副基准辐射源。一、建立（200－350）urn光谱辐亮度副基准实验装置本实验装置包括等离子体氛弧、氮弧的供水供气系统、氨弧电源、两个单色仪及其光学系统、波长驱动及其测量自动化系统，标准钨带灯和标准氛灯。等离子体壁稳氨弧由钨制的阴极、阳极和15片紫铜叠片组成，全部水冷。弧片间用厚度为27mm的聚脂塑料环隔开绝缘。氮弧的真…     

基于分段线性法的红外辐射计响应度标定研究

基于溯源至国家高温基准的黑体辐射源对SR 5000N型辐射计光谱响应度进行标定。建立了系统响应度标定模型,在373～773K温区进行了响应度标定实验。实验结果表明:在此温区内黑体理论光谱辐射亮度与基于校准的光谱响应度得到的黑体光谱辐射亮度在8～14μm频谱内的相对平均偏差优于1%,具有较好的一致性。     

真空汞固定点黑体辐射源的设计与研制

介绍了中国计量科学研究院研制的真空汞固定点黑体辐射源的结构、工作原理、性能测试结果和不确定度分析。真空汞固定点黑体辐射源灌注的是纯度为99.9999%的高纯汞,黑体空腔开口直径为25 mm,空腔内径为28 mm,深度为260 mm,表面喷涂了NEXTEL 811-21高发射率涂层,采用基于蒙特卡罗黑体发射率仿真计算的方法,计算了黑体空腔在波长为8~14μm的发射率,结果优于0.9999;在真空环境下,测试了真空汞固定点黑体辐射源的温坪曲线和重复性等主要技术指标,结果表明真空汞固定点黑体辐射源温坪稳定性优于2 mK,多次重复性优于1 mK;分析了真空汞固定点黑体辐射源的不确定度来源,其合成标准不确定度为16 mK。     

红外高光谱大气探测仪星载固定点黑体辐射源的研制

介绍了中国计量科学研究院为风云三号05星红外高光谱大气探测仪研制的微型镓固定点星载黑体辐射源。设计了黑体辐射源空腔,其有效发射率优于0.997。针对星载固定点黑体辐射源的结构设计和性能测试展开了研究:星载固定点黑体辐射源17 ℃的温度均匀性仿真结果优于0.01℃;黑体辐射源在真空下均匀性优于0.02 ℃,稳定性优于0.002 ℃(90 min内);在通过满足航天应用的力学冲击等实验后,镓固定点的复现性优于0.03 ℃;微型固定点相变温坪复现实验加热功率与拐点值之间存在较好的线性关系。     

JJG 2048-201《1500K~1000K全辐照计量器具》检定系统表解读

一、概述全辐照基准黑体辐射源是复现辐射学量值的基础,是红外辐射量值传递的国家唯一基准装置,而温度(K)和光强(cd)两个基本量复现是由辐射学实现的。基准装置建于1980年,经1995年和2007年的两次技术改造,研制了4个凝固点黑体(铟、锡、锌、铝)和红外成像器件参量测量的标准装置,由亮度法以金属凝固点黑体组将量值传递到下一级标准器,不确定度由     

Bilateral Comparison of Spectral Irradiance Between NIM and VNIIOFI from 250 to 2500 nm

With the new spectral irradiance measurement facility based on blackbody BB3500M of National Institute of Metrology (NIM), a bilateral spectral irradiance comparison was carried out between NIM and VNIIOFI (All Russian Research Institute for Optical and Physical Measurements) in the spectral wavelength from 250 to 2500 nm for the period of January 2015 to June 2016. The temperature measurement of the high temperature blackbodies were traced to the Pt–C and Re–C fixed point blackbodies and checked against the WC–C fixed-point blackbody for the two institutes respectively. The consistency of the temperature at 3021 K is better than 70 mK. The comparison result shows that the average relative deviation of spectral irradiance at 44 designated wavelengths is 0.45%. The consistency is better than 0.9% except the maximum deviation 1.1% at the wavelength of 2000 nm. The spectral irradiance units measured by NIM and VNIIOFI in this comparison are in agreement within the combined standard uncertainties of the laboratories over the wavelength range compared.     

NIST Radiance Temperature and Infrared Spectral Radiance Scales at Near-Ambient Temperatures

The realization and the dissemination of spectral radiance and radiance temperature scales in the temperature range of −50 to 250°C and spectral range of 3–13 μm at the National Institute of Standards and Technology are described. The scale is source-based and is established using a suite of blackbody radiation sources, the emissivity and temperature of which have been thoroughly investigated. The blackbody emissivity was measured using the complementary approaches of modeling, reflectometry, and the intercomparison of the spectral radiance of sources with different cavity geometries and coatings. Temperature measurements are based on platinum resistance thermometers and on the direct use of the phase transitions of pure metals. Secondary sources are calibrated using reference blackbody sources, a spectral comparator, a controlled-background plate, and a motion control system. Included experimental data on the performance of transfer standard blackbodies indicate the need for development of a recommended practice for their specification and evaluation. Introduced services help to establish a nationwide uniformity in metrology of near-ambient thermal emission sources, providing traceability in spatially and spectrally resolved radiance temperature, spectral radiance, and background-corrected effective emissivity.     

Standard of Spectral Radiance for the Region of 0.25 to 2.6 Microns

This paper contains information relating to the setting up of standard blackbodies for use through the temperature range of about 1,400° to 2,400° K and their use in the calibration of tungsten strip lamps as laboratory standards of spectral radiance for the wavelength region of 0.25 to 2.6 microns. A graphite blackbody is described and representative data are given on the spectral characteristics of the new lamp standard as compared to blackbodies at several selected temperatures.     

T 90 Measurement of Co-C, Pt-C, and Re-C High-Temperature Fixed Points at the NIM

The blackbodies of high-temperature fixed points (HTFPs), namely, Co-C, Pt-C, and Re-C eutectic points, were gradually established at the National Institute of Metrology (NIM) of China after 2007, and their characteristics were studied. Recently, the primary standard pyrometer was improved with the lower size-of-source effect, distance effect, and partial temperature controls. The pyrometer was characterized at the new facility for the calibration of the spectral responsivity. The measurement of its nonlinearity extended to a primary standard pyrometer (PSP) reading of approximately 2680 °C for the HTFP measurements. The International Temperature Scale of 1990 above the silver point was realized at the NIM by an improved scheme, the fixed-point blackbody pyrometer assembly. Two cells each for Co-C, Pt-C, and Re-C points were assigned associated uncertainties (k = 2) of 0.22 °C, 0.37 °C, and 0.75 °C, respectively, in accordance with the NIM scale. These HTFP blackbodies are being adopted for the study and calibration of radiation thermometers at the NIM.     

黑体辐射源的多波长有效亮度温度校准和不同溯源方式特点分析

介绍了中国计量科学研究院建立的标准变温黑体辐射源和有效亮度温度比较装置;阐述了黑体辐射源多波长有效亮度温度校准的2种方法,给出典型校准结果并分析了辐射源特性。比较分析了3种溯源方式的性能特点及其应用的影响因素。提出控温复现性的概念,它是以往未被重视的辐射源关键性能参数。多波长有效亮度温度校准是可减小或消除有效发射率和接触测温测点温差影响的溯源方案,与传统溯源方式特性互补,可用于评价辐射源的有效发射率和测点温差,对控温复现性好的辐射源效果最优。     

Metrological Investigation of Pyrographite High-Temperature Blackbodies

The results are reported from experimental investigations of the spectral radiance and irradiance distributions, the temperature gradient, and the effective emissivity of the radiating cavity of high-temperature pyrographite blackbodies designed at VNIIOFI (Scientific-Research Institute of Optophysical Measurements). An experimental method of determining the effective high-temperature emissivity of a blackbody is described.     

Design and Evaluation of Large-Aperture Gallium Fixed-Point Blackbody

To complement existing water bath blackbodies that now serve as NIST primary standard sources in the temperature range from 15 °C to 75 °C, a gallium fixed-point blackbody has been recently built. The main objectives of the project included creating an extended-area radiation source with a target emissivity of 0.9999 capable of operating either inside a cryo-vacuum chamber or in a standard laboratory environment. A minimum aperture diameter of 45 mm is necessary for the calibration of radiometers with a collimated input geometry or large spot size. This article describes the design and performance evaluation of the gallium fixed-point blackbody, including the calculation and measurements of directional effective emissivity, estimates of uncertainty due to the temperature drop across the interface between the pure metal and radiating surfaces, as well as the radiometrically obtained spatial uniformity of the radiance temperature and the melting plateau stability. Another important test is the measurement of the cavity reflectance, which was achieved by using total integrated scatter measurements at a laser wavelength of 10.6 μm. The result allows one to predict the performance under the low-background conditions of a cryo-chamber. Finally, results of the spectral radiance comparison with the NIST water-bath blackbody are provided. The experimental results are in good agreement with predicted values and demonstrate the potential of our approach. It is anticipated that, after completion of the characterization, a similar source operating at the water triple point will be constructed. Certain commercial equipment, instruments, or material are identified in this paper to specify the experimental procedures and result adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that material or equipment identified are necessarily the best available for the purpose.