Report of the spectral irradiance comparison EURAMET.PR-K1.a.1 between MIKES (Finland) and NIMT (Thailand)

A bilateral comparison of the spectral irradiance scales between MIKES (Finland) and NIMT (Thailand) was carried out at 22 wavelengths between 290 nm and 900 nm. MIKES acted as the pilot and link to the results of the key comparison CCPR-K1.a. The spectral irradiance values measured by NIMT generally agree with the key comparison reference value within the expanded uncertainty. The only exceptions are results at wavelengths 300 nm, 450 nm and 500 nm, where the ratios between the degree of equivalence (DoE) and the expanded uncertainty of DoE (k = 2) are 1.0, 1.4 and 1.2, respectively. [PUBLICATION ABSTRACT]