Table 3.
Determination of the photometric responsivity of the NIST transfer photometer compared to that of a PTB photometer
| Date of measurement 1993 | Pack. temp. Tp K |
Photometric responsivity s*(Tp) mV/lx |
Corrected responsivity s*(297.0) mV/lx |
Difference | ||
|---|---|---|---|---|---|---|
|
| ||||||
| NIST | PTB | NIST | PTB | (NIST-PTB)/PTB | ||
| April | 297.0 | 23.120 | 23.120 | |||
| August | 297.5 | 23.174 | 23.183 | |||
| October | 297.1 | 23.176 | 23.178 | |||
| December | 297.4 | 23.135 | 23.142 | |||
|
| ||||||
| Average | 297.3 | 23.131 | 23.181 | −0.22% | ||
| Δa | 0.09% | 0.02 % | ||||
|
| ||||||
| Ulabb | 0.13 % | 0.03 % | ||||
|
| ||||||
| Difference between photometric responsivity values measured by NIST and PTB: −0.22 %±0.14 %(U) | ||||||
a
Δ is the difference of the two measurements at each laboratory, [s*(first)-s*(second)]/s*(first).
b
Ulab is two times the standard deviation of the responsivity values at each laboratory. U is the quadrature sum of Ulab(NIST) and Ulab(PTB).