Table 18.
Expanded uncertainty (k = 2) in radiance temperature for an argon-filled ribbon filament lamp in the RTCL. The uncertainty, in °C, is given for different radiance temperatures (also in °C)
| Source of Uncertainty | Type | Radiance temperature (°C) | ||||
|---|---|---|---|---|---|---|
| 800 | 1100 | 1500 | 1900 | 2300 | ||
| Calibration of the reference radiance temperature lamp relative to the 1990 NIST Radiance Temperature Scale | B | 0.12 | 0.19 | 0.32 | 0.48 | 0.67 |
| Test lamp temperature determination | A | 0.42 | 0.17 | 0.29 | 0.43 | 0.60 |
| Lamp current measurement | B | 0.29 | 0.19 | 0.15 | 0.14 | 0.14 |
| Mean effective wavelength measurement for the NIST PEP | B | 0.10 | 0.04 | 0.09 | 0.28 | 0.54 |
| Test lamp alignment | B | 0.09 | 0.14 | 0.24 | 0.36 | 0.51 |
| 1990 NIST Radiance Temperature Scale relative to thermodynamic temperature scale | B | 0.15 | 0.24 | 0.40 | 0.61 | 0.85 |
| Overall uncertainty of test lamp calibration with respect to SI units | B | 0.6 | 0.4 | 0.7 | 1.0 | 1.5 |