Table 1.

Relative standard uncertainty components^a

Source of uncertainty	Relative standard uncertainty (%)
Voltage from the main detector amplifier, Vtest	0.014
Voltage from the main detector amplifier, Vstd	0.014
Voltage from the monitor detector amplifier, $V_{{\text{mon}}_{\text{test}}}$	0.014
Voltage from the monitor detector amplifier, $V_{{\text{mon}}_{\text{std}}}$	0.014
Irradiance at the test plane during meas. of unknown aperture, Eλtest	0.018
Irradiance at the test plane during meas. of standard aperture, $E_{\mathrm{\lambda }}^{\text{std}}$	0.018
Standard aperture area, Astd	0.022
Mirror reflectance nonuniformity(b)	0.01
Sphere source aperture area (% per degree Celsius)(b)	0.0034
Corrected lamp Drift(b)	<<0.01
DVM uncertainty(b)	0.005
DVM linearity(b)	0.0035
Amplifier drift (% per dgree Celsius)(b)	0.003
Relative combined standard uncertainty of the measurement, uc,r(Atest)	0.04

^aAll uncertainties are type A.

^bIndicates a quantity which was measured for completeness but not included in the uncertainty calculations.