• Journal of Sensor Science and Technology
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• v.13 no.6
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• pp.411-416
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• 2004

In the international temperature scale of 1990 (ITS-90), standard platinum resistance thermometer (SPRT) is a defining standard thermometer used in the temperature range from 13.8033 K to $961^{\circ}C$. Uncertainty of SPRT is about several mK and uncertainty of defining fixed points of the ITS-90 which is used for calibrating SPRT is about several tenth of mK. Above $0^{\circ}C$. the defining fixed points are gallium melting point and indium, tin, zinc, aluminium and silver freezing points which are all realized using an electric furnace or a liquid bath. To realize freezing point of tin ($231.928^{\circ}C$) and zinc ($419.527^{\cir}C$), two 3-zone furnaces which have 3 electric heaters were manufactured. Temperature gradient of the constructed furnaces were tested. Uncertainty caused by temperature gradient of furnace and immersion effect of SPRT in the sealed-type freezing point cells were evaluated 0.038 mK for tin freezing point and 0.036 mK for zinc freezing point.

• Journal of Sensor Science and Technology
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• v.14 no.4
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• pp.231-236
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• 2005

Calibration capability was evaluated using the reference-grade platinum resistance thermometer (PRT) in the temperature range of $-50^{\circ}C$ to $250^{\circ}C$ for the national calibration centers. The reference-grade PRT was calibrated at the several fixed points, which was composed by the freezing points of Sn, In, the melting point of Ga and the triple point of water and Hg, before and after the round-robin test (RRT) experiments. The temperature scale of reference-grade PRT was compared to the local standard PRT's using the system of the national calibration centers. $E_{n}$ values was calculated by the temperature difference between the reference-grade PRT and the local standard PRT, and the best measurement capability. Finally, the capability of the national calibration centers was evaluated by the $E_{n}$ values.

• Journal of Sensor Science and Technology
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• v.18 no.1
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• pp.86-94
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• 2009

Temperature measurement capability was inter-compared using the transfer standard platinum resistance thermometers(SPRT) among four laboratories of KRISS. The transfer SPRTs were primarily calibrated at the triple point of water and Ga melting point, then used at inter-comparison experiment. Temperature difference of calibration value between temperature laboratory and length laboratory at $20^{\circ}C$ was -0.7 mK and +2.4 mK at density laboratory. Temperature measured near $20^{\circ}C$, $25^{\circ}C$ and $30^{\circ}C$ at fluid flow laboratory was deviated by $34.2{\sim}80.4\;mK$ from the calibration values of the transfer SPRT. Ga melting points was inter-compared among three laboratories, and the difference of Ga melting points against the standard Ga melting point of temperature laboratory were $0.03{\sim}0.54\;mK$ at length laboratory and 0.02 mK at density laboratory.

• Journal of Sensor Science and Technology
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• v.18 no.4
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• pp.322-326
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• 2009

To estimate the measurement uncertainty for industrial platinum resistance thermometers(IPRTs) made with 3-wire connection, the immersion temperature profile was investigated using a liquid bath. Two types of IPRTs having lead wires made of silver and nickel were constructed and the immersion profiles were measured at temperatures from -50 $^{\circ}C$ to 250 $^{\circ}C$ using 3-wire and 4-wire method. As immersion depth and temperature increased, the resistances measured by 3-wire method increased linearly but not for 4-wire method. To calibrate a 3-wire IPRT, the immersion effect must be accounted for. We propose a linear equation to assess correctly the measurement uncertainty.

• Journal of Sensor Science and Technology
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• v.9 no.3
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• pp.153-162
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• 2000

Triple points of high purity materials have been used to calibrate primarily the capsule-type platinum resistance thermometer (PRT) in the temperature range of the triple point of equilibrium hydrogen (13.8033 K) and water (273.16 K). In this work, triple points of Ne, $O_2$, Ar, Hg and $H_2O$ except for the triple point of equilibrium hydrogen were realized to establish the International Temperature Scale of 1990 (ITS-90). At each fixed point, two capsule-type PRTs, which were selected for the international comparison, were tested two times. The combined uncertainties of the realization of each triple point were calculated considering the type A and type B evaluation. In Korea Research Institute of Standards and Science, the combined standard uncertainties of the defining triple Points by the ITS-90 were estimated to about 0.18 mK for Ne, 0.14 mK for $O_2$, 0.14 mK for Ar, 0.24 mK for Hg and 0.11 mK for $H_2O$, respectively.

• Journal of Sensor Science and Technology
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• v.18 no.2
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• pp.116-121
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• 2009

Pressure-controlled sodium heat pipe furnace was designed and fabricated, and its characteristics was investigated. Pressure control system was controlled within ${\pm}0.5\;Pa$ at 150 kPa and the stability of pressure was decreased to ${\pm}2.5\;Pa$, when the pressure-controlled system connected with the heat pipe. The melting curve of Ag fixed-point realized well by the adiabatic method using the pressure-controlled sodium heat pipe furnace and its accuracy showed ${\pm}2.27\;mK$ from the calculation of 20% to 80% at the plateau. The freezing curve of Ag fixed-point also realized and its plateau value was 2.23 mK lower than that of the melting curve.

• Journal of Sensor Science and Technology
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• v.31 no.6
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• pp.448-454
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• 2022

An intralaboratory comparison of the realization of the triple-point temperature of mercury, which is defined as -38.8344℃ on the international temperature scale of 1990 (ITS-90), was conducted at the Korea Research Institute of Standards and Science (KRISS), the national metrology institute of Korea. To this end, four triple-point-of-mercury cells were compared using the resistance ratio measurement of a standard platinum resistance thermometer to validate the calibration results obtained using the triple-point-of-mercury cells at KRISS. The triple-point temperatures of all the four cells, one of which is designated as the national standard cell, were within 0.3 mK of the national standard. Based on 13 experiments on the four triple-point-of-mercury cells, the uncertainty in the comparison of the triple-point-of-mercury cells was 0.08 mK, and the uncertainty in the realization of the triple-point temperature of mercury was 0.19 mK. The results of the intralaboratory comparison validated that utilizing any of the four triple-point-of-mercury cells would result in the realization of a temperature within 0.3 mK of the average value determined by two key international comparisons for the realization of -38.3844℃ following the ITS-90.