초록
$0^{\circ}C$ 이하 적외선 복사온도계의 복사온도눈금 교정을 위해 기준 복사온도계 TRT2 (Transfer Radiation Thermometer 2, HEITRONICS)와 온도가변 흑체 ME30 (Model: ME30, HEITRONICS)을 사용하여 비교 교정장치를 구축하였다. 3개의 고정점(Ice ($0.01^{\circ}C$), In ($156.5985^{\circ}C$), Sn ($231.928^{\circ}C$))과 플랑크형 사쿠마-하토리식을 사용하고, $-50^{\circ}C$에서 TRT2의 내외삽 오차를 불확도에 포함시켜 TRT2의 복사온도 눈금을 교정하였다. ME30 흑체 개구에 공압으로 동작되는 뚜껑을 설치한 후 30초 동안만 뚜껑을 열고 복사온도를 측정함으로써 ME30 내에서 생기는 성에를 방지할 수 있었으며 비교 교정에 소요되는 시간도 반으로 줄일 수 있었다. $0{\sim}232^{\circ}C$ 영역 밖으로 벗어날수록 비교 교정장치의 불확도는 증가하며 $-20^{\circ}C$에서 확장 불확도는 0.26 K였다.
Comparison calibration equipment for infrared-radiation thermometers below $0^{\circ}C$ has been established, using a TRT2 (transfer radiation thermometer 2, HEITRONICS) as a transfer standard and an ME30 (Model: ME30, HEITRONICS) as a variabletemperature blackbody. The TRT2 was calibrated using three fixed points (Ice ($0.01^{\circ}C$), In ($156.5985^{\circ}C$), and Sn ($231.928^{\circ}C$)) and the Planckian Sakuma-Hattori equation, and including the interpolation and extrapolation errors at $-50^{\circ}C$ in the uncertainty. The pneumatic lid is installed upon opening of the ME30 and is opened for only 30 seconds for measuring the radiation temperature, which prevents formation of ice in the ME30 and also reduces the calibration time to half. The farther away from the $0{\sim}232^{\circ}C$ region, the larger the uncertainty of the comparison calibration equipment becomes. The expanded uncertainty of the comparison calibration equipment was estimated as 0.26 K at $-20^{\circ}C$.
