铑铁电阻温度计工作基准装置研究

A reference standard facility for rhodium-iron resistance thermometers

利用新式低温控温仪及精密自动电桥,建立了一套铑铁电阻温度计工作基准装置,并设计制造了新型低温绝热比对恒温器。采用比对方法对组成"1.2～24K温区的ITS-90国家温度基准组"的铑铁电阻温度计进行了比对测量;对5支标准铑铁电阻温度计进行1990年国际温标(ITS-90)转换和电学单位转换,拟合计算分度数据作为铑铁电阻温度计工作基准装置分度表;利用本套铑铁电阻温度计工作基准装置进行40个温度点的比对测量。结果表明,本套基准装置控温水平达到0.4 mK/30 min,5支铑铁电阻温度计示值与平均值差值全部小于0.88 mK,比对测量不确定度为0.95 mK,证明本套装置测量数据准确、性能可靠,可作为1.2～24 K温区国家工作基准使用。

A reference standard facility for rhodium-iron resistance thermometers （RIRT） has been established. A new cryostat was designed, and a new automatic low temperature controller and a precision bridge were used to measure the five RIRTs which make up the ＂National Temperature Working Standard Group of the ITS-90 at 1.2 - 24 K＂. The design principles and the technical features of the cryostat were investigated. The five RIRTs were transformed to the International Temperature Scale of 1990 （ITS-90） and a set of indexing data was fitted and calculated as the indexing table of the reference standard facility of RIRT. 40 basis temperature points were measured using this reference standard facility set. The results showed that the control temperature level could reach 0.4 mK/30 min. The difference between the temperature values of the five RIRTs and their average was less than 0. 88 mK. It was shown that the measurements of this reference standard facility were accurate and the performance was reliable. This reference standard facility of RIRT can serve as the national reference standard facility at 1.2 - 24 K.