A device for the in-situ monitoring of EUV radiation flux includes an integrated reflective multilayer stack. This device operates on the principle that a finite amount of in-band EUV radiation is transmitted through the entire multilayer stack. This device offers improvements over existing vacuum photo-detector devices since its calibration does not change with surface contamination.
This invention was made with Government support under Contract No. DE-AC04-94-AL85000 awarded by the U.S. Department of Energy to Sandia Corporation. The Government has certain rights to the invention.