Subcomparison CCPR-K1.b of the CCPR key comparison of spectral irradiance covering 200 nm to 400 nm will be carried out in 2002/03 piloted by the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig, Germany. Deuterium arc lamps will be used as transfer standards of spectral irradiance, although they are known to have, in general, poor stability and reproducibility. PTB investigated a variety of deuterium lamps to test their capability (stability and reproducibility) for use as transfer standards. A measurement facility capable of characterizing up to three lamps at a time has been set up. Investigations of the spectral ageing pattern will help to interpolate between different reference measurements to markedly reduce the influence of ageing effects. The application of an external SiC photodiode as a monitor detector was tested. Spatial characterization of the irradiance of each lamp was also carried out. All this all helped us to find suitable types of lamp, producing reasonable irradiance homogeneously enough to be non-sensitive to small misalignments.
展开▼
