46 cm long and 4 mm in diameter, with a pyrex-enclosed reference junction and with 150 cm selected copper leads. Calibrations are performed by comparison against SPRTs or standard thermocouples which determine the calibration temperature. The comparison facilities include a variety of baths, furnaces, and cryostats. This service is performed only when it is necessary to anneal an instrument or to perform additional tests to assess its stability. This service tests one instrument at one calibration temperature within the specified range.
Separate fees apply to each instrument and each calibration temperature.
A calibration consists of five to ten data points within the range of the instrument. As a consequence, the lamp calibration is valid only near 660 nm. Above this temperature, lamps filled with an inert gas must be employed to avoid excessive vapourization of the filament. The gas-filled lamps are calibrated by scaling procedures based on a vacuum lamp as the standard source, rather than a blackbody. Other pyrometers and radiation thermometers may be calibrated by special arrangement.