First results of measurements with the BIPM cryogenic radiometer and comparison with the INM cryogenic radiometer

This is the authors' abstract. We don't add key points for this paper.

An Oxford Instruments Radiox cryogenic radiometer was recently installed at the Bureau International des Poids et Mesures (BIPM). The first measurements were aimed at characterizing the performance of the system. The Radiox was then compared with the cryogenic radiometer of the French Institut National de Métrologie (INM), a CRI LaseRad, at the BIPM by successive measurements of the power in a laser beam at two wavelengths: 647 nm and 476 nm. The radiometers differed in these measurements by 1,9 parts in 10 4 , the uncertainties in each being smaller than 1 part in 10 4 .