Calibration of Thermocouples and Infrared Radiation Thermometers by Comparison to Radiation Thermometry

The National Metrology Institute of Spain (CEM) has designed, characterized, and set-up its new system to calibrate thermocouples and infrared radiation thermometers up to 1600 °C by comparison to radiation thermometry. This system is based on a MoSi₂ three-zone furnace with a graphite blackbody comparator. Two interchangeable alumina tubes with different structures are used for thermocouples and radiation thermometer calibrations. The reference temperature of the calibration is determined by a standard radiation thermometer. Normally, this is used at CEM to disseminate the International Temperature Scale of 1990 (ITS-90) in the radiation range, and it refers to the Cu fixed point. Several noble metal thermocouples and infrared radiation thermometers with a central wavelength near 900 nm have been calibrated, and their uncertainty budgets have been obtained.     

Pure Nickel Fixed Points for Contact Thermometry Calibrations

A robust fixed point using pure nickel contained in an alumina crucible has been developed for thermocouple calibrations. It was observed that a deep supercool often caused the freezing plateau to be short and have a large slope. A procedure for realizing the pure nickel fixed points was developed that reserved a small amount of nickel in the solid state to act as a seed for nucleation of the freeze. This procedure was found to allow freezing plateaus that were suitably long and flat to make them useful for calibrating thermocouples. Using a calibrated Pt/Pd thermocouple, the freezing temperature of nickel was determined to be \(1455.22\,^{\circ }\hbox {C}\) with a \((k = 2)\) uncertainty of \(0.8\,^{\circ }\hbox {C}\) .     

Intercomparison of Copper Fixed-Point Cells by Using Pt/Pd Thermocouples

The objective of the EUROMET Project No. 844 in the field of thermometry was the intercomparison of the freezing temperatures of the copper fixed-point cells (t ₉₀ = 1084.62°C) of the participating laboratories by using Pt/Pd thermocouples. For most of the 13 participating laboratories, agreement of the freezing temperatures of the different copper fixed points within ±0.06 K was found. Furthermore, the results of the intercomparison show that Pt/Pd thermocouples are suitable for use as transfer standards for the dissemination of temperatures and to approximate the ITS-90, at least up to the freezing point of copper.     

铂铑—铂热电偶稳定的探讨

本文对铂铑-铂热电偶的稳定性提出了新的看法,在高温梯度场内（如银熔点）的保温处理,将使热电偶更趋于稳定,并使其进入最终的稳定状态。     

改进型封装固定点黑体在辐射测温中的应用

为了延长固定点黑体容器使用寿命和简化使用流程,依据热管黑体和传统石墨坩埚黑体的设计使用经验,研制了改进型封装固定点黑体。针对所研制的锡固定点黑体分别用二等标准铂电阻和传递辐射温度计开展复现测试。改进型封装固定点黑体在经历20余次熔凝循环后,没有出现破裂和金属泄露现象。用标准铂电阻复现多次的平均值为231.909℃,扩展不确定度为0.015℃(k=2);而用固定点黑体校准传递辐射温度计的多次平均值为231.85℃,扩展不确定度为0.096℃(k=2)。     

铂-钯热电偶的均匀性及稳定性实验

本文着重描述了对一种新型热电偶———铂 -钯热电偶的主要热电性能即均匀性与稳定性的研究。其结果此热电偶的不均匀性不大于 10mK ,在 96 0℃下放置 2 30小时漂移不大于 71mK。     

A Concerted International Project to Establish High-Temperature Fixed Points for Primary Thermometry

Research into high-temperature fixed points above 1,100°C has made significant progress since they were first reported in 1999. In particular, it has been established that single cells are repeatable at the sub-50 mK level, and intra-cell reproducibility at the 100 mK level has been demonstrated even at temperatures as high as 2,500°C. The fixed points have been used to compare temperature and radiometry scales over a wide temperature range, and are being developed and established as secondary references for thermocouple calibrations. However, before they can be fully accepted as primary temperature references, much work remains to be done, namely: (1) Establishment of long-term stability of the fixed-point temperature; (2) Development of robust procedures for the reliable construction of the fixed-point cells (to ensure routine intra-cell reproducibility of 100 mK); (3) Demonstration of long-term robustness of the fixed-point cells; (4) Assignment of thermodynamic temperatures to a selected set of fixed points; (5) Agreement and acceptance of these temperature values by the CCT; (6) Agreed methods on how to take full utility of these new fixed points into any future International Temperature Scale (ITS)—or the current ITS-90 via an addendum to the mise en pratique for the definition of the kelvin. To ensure that this work progresses to completion in a reasonable time frame, a research project, under the auspices of the CCT-WG5, has been formulated and is currently in progress with the aim of achieving the above mentioned targets by 2012. This article will describe this project and detail partner contributions.     

Thermodynamic Radiation Thermometry Using Radiometers Calibrated for Radiance Responsivity

Using radiometry, thermodynamic temperatures can be determined by a variety of experimental techniques. Radiometers without imaging optics can be calibrated for spectral power or spectral irradiance responsivity, and radiometers with imaging optics can be calibrated for radiance responsivity. These separate approaches can have different uncertainty components with different uncertainty values. At NIST, thermodynamic radiation thermometry is performed using radiation thermometers calibrated for radiance responsivity using laser-irradiated integrating sphere sources (ISS). The radiance of the ISS is determined using Si-trap detectors whose spectral power responsivity is traceable to the electrical substitution cryogenic radiometer. The radiometric basis of the NIST approach is discussed. The uncertainty budget for the measurements as well as the characterizations to determine the component uncertainty values is listed.     

Thermodynamic Temperature of High-Temperature Fixed Points Traceable to Blackbody Radiation and Synchrotron Radiation

Absolute spectral radiometry is currently the only established primary thermometric method for the temperature range above 1300 K. Up to now, the ongoing improvements of high-temperature fixed points and their formal implementation into an improved temperature scale with the mise en pratique for the definition of the kelvin, rely solely on single-wavelength absolute radiometry traceable to the cryogenic radiometer. Two alternative primary thermometric methods, yielding comparable or possibly even smaller uncertainties, have been proposed in the literature. They use ratios of irradiances to determine the thermodynamic temperature traceable to blackbody radiation and synchrotron radiation. At PTB, a project has been established in cooperation with VNIIOFI to use, for the first time, all three methods simultaneously for the determination of the phase transition temperatures of high-temperature fixed points. For this, a dedicated four-wavelengths ratio filter radiometer was developed. With all three thermometric methods performed independently and in parallel, we aim to compare the potential and practical limitations of all three methods, disclose possibly undetected systematic effects of each method and thereby confirm or improve the previous measurements traceable to the cryogenic radiometer. This will give further and independent confidence in the thermodynamic temperature determination of the high-temperature fixed point’s phase transitions.     

校准短型廉金属热电偶相关问题的研究

短型廉金属热电偶是一类电极长度较短的可拆卸式廉金属热电偶和廉金属铠装偶的统称。传统的测量设备和测量方法在高温温区往往无法准确测量其示值偏差。通过实验找到其测不准的原因,设计研发接线端恒温器解决这一问题,降低了短型偶示值偏差的扩展不确定度。     

基于弹性夹具的辐射温度计检定装置研究

针对目前工作用辐射温度计检定工作存在的问题，提出一种基于弹性夹具的高重复性精度的辐射温度计检定装置。通过介绍装置结构和使用方法，阐明利用弹性夹具固定被检温度计具有更高的灵活性和通用性，以及“一副夹具安装一台被检，共用一个检定台”方式具有更高的机械化程度和工作效率。通过检测和试验结果表明，该装置重复性精度高。     

辐射测温学研究进展

系统介绍了近年来辐射测淡不巫基础研究到应用研究的４个研究方向：热力学温度绝对测量，１ＴＳ－９０国际温标复现与比对，辐射法真温测量和应用技术研究，并针对辐射测温学的前沿课题提出了适宜于我国的研究方向。     

热电偶补偿导线的校准方法

热电偶用补偿导线指在一定温度范围内(包括常温)具有与所配的热电偶的热电动势的标称值相同的一对带有绝缘层的导线,用它们连接热电偶与测量装置,以补偿它们与热电偶连接处的温度变化所产生的误差。所以热电偶补偿导线的准确性直接影响到与热电偶整体测温的准确。     

基于LabVIEW实现固定发射率辐射温度计校准的温度修正

在辐射温度计检定中,根据规程要求,需要将辐射温度计的发射率设置为1,而在实际校准辐射温度计的过程中发现大量发射率固定且不为1的情况,同样有用户要求校准后给出不同发射率下的辐射温度计修正值,为实现宽波段任意固定发射率辐射温度计在校准过程中的修正值计算,文章使用LabVIEW的两分法迭代实现Plank公式的积分算法,有效提高校准过程的自动化程度,文章用实例说明了两分法与普通步进算法的效率区别,从而高效的实现了任意波段、任意发射率、任意温度点的温度修正值计算。     

Middle Temperature Scale for Infrared Radiation Thermometer Calibrated Against Multiple Fixed Points

The NMIJ has established a temperature scale for infrared radiation thermometry from 100 to 420°C consisting of three fixed-point blackbodies at the In, Sn, and Zn points and an InSb detector thermometer at a wavelength of 4.7 μm. The blackbody cavities have large openings of 15 mm diameter. The expanded uncertainties (k = 2) of the In, Sn, and Zn fixed-point radiance temperatures are estimated to be 0.03, 0.03, and 0.05 K, respectively. The expanded uncertainties (k =  2) for the calibration of the infrared radiation thermometer are estimated to be 0.04 K at 157°C (In point), 0.04 K at 232°C (Sn point), and 0.07 K at 420°C (Zn point).     

Pt/Au/p-Si溅射薄膜组织结构特征

在p-Si衬底上,分别淀积5 nm Au膜和5nmPt膜,形成Pt/Au/p-Si结构,500℃退火后形成硅化物薄膜.采用X射线光电子谱和X射线衍射谱研究薄膜成分和相分布,利用原子力显微镜和高分辨电子显微镜观察薄膜表面形貌和界面结构.测试结果表明,薄膜中含有PtSi相和Au相,表面较平坦,PtSi相形成层状结构,Au原子聚集成岛状结构.     

Construction and Investigation of Pt/Pd Thermocouples in the Framework of the Euromet Project 857

The objective of the EUROMET Project 857 in the field of thermometry, “High-temperature fixed points for improved thermocouple calibrations,” is the development of robust high-temperature fixed points based on metal-carbon eutectic alloys for the calibration of thermocouples above 1,084°C. This paper describes the construction and investigation of Pt/Pd thermocouples to be used to compare different cobalt–carbon (Co–C) fixed-point cells constructed by the three participants of this project. A set of three Pt/Pd thermocouples was prepared by PTB and NPL and a set of four by LNE. Their metrological performances in terms of thermoelectric stability and homogeneity were assessed in different ways. The results of these investigations, as well as the results of first measurements of local Co–C eutectic fixed-point cells by using Pt/Pd thermocouples, are presented.     

多光谱辐射测温理论综述

介绍了多光谱辐射测温理论的研究现状，即多光谱辐射测温法的3种数学模型的建立方法和多波长辐射温度计的8种数据处理方法，并分析了各自的特点。