Indirect comparison of cryogenic radiometers from the INM (France) and the VTT (Finland) with a QED-200 from the VSL (Netherlands)

This paper gives the results of an indirect comparison of a cryogenic radiometer from the Institut National de Metrologie (INM), France, and from the Technical Research Centre of Finland (VTT) with a QED-200 from the Van Swinden Laboratorium (VSL), the Netherlands. This comparison was performed at a laser wavelength of 543,515 nm (in vacuum) and at a power level of 100 mu W. If this QED-200 is assumed to be stable with time, then two cryogenic radiometers of different design have been shown to agree to 3x10(-5) with an uncertainty of 3x10(-4) at the 1 sigma level.