Performance of transmission filters for EUV and soft x-ray astronomy

Soft x-ray detectors for astronomical applications are often also sensitive to visible and UV photons. Filters of a new design have been developed, which could be used in future missions to suppress the flooding of x-ray detectors by low energy photons. Three series of filters are discussed: aluminum/silicon multilayers, Niobium and calcium/boron multilayers. The filters are typically 100 to 200 nm thick and reject the IR/visible/UV from 10-4 to 10-6. The transmission for soft x-rays is above 10% for wavelengths less than 30 nm, when combining the bandpasses of at least two filters. The optimum transmission band depends very much on the filter type. The IR/visible/UV has been measured using standard laboratory spectro- photometers while the x-ray transmission characteristics have been determined using synchrotron radiation.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.