Improved Materials and Structures for Large Area Cryogenic Detector Windows

Cryogenic soft X-ray detectors are enabling new analytical capabilities for science, engineering, materials characterization, and time-resolved studies. X-ray microcalorimeter detectors are increasingly being used at synchrotron light sources, with scanning electron microscopes and other analytical instrumentation. These detectors must be protected from the environments in which they operate by soft X-ray transparent windows. As the size of these detectors increases to improve their sensitivity, x-ray window area must also increase without otherwise compromising the instruments. Luxel proposes two types of innovations in Phase 1, pressure windows with improved structural grids and improved filter membranes. The new grid design and fabrication concepts overcome previous limitations of grid performance and cost. The improved membranes offer higher soft X-ray transparency, improved strength and reduced spectral artifacts. The Phase 1 effort will result in a suite of improved filter materials that can be combined in various ways to address the demanding requirements for pressure windows and radiation shields in cryogenic x-ray detectors. Luxel will generate large-area prototypes of each of the proposed grid innovations, and small- window prototypes incorporating the proposed membrane improvements. The Phase 1 work comprises two tasks for producing the large prototype grids, and three tasks to produce the improved membrane elements. Activities include precision alignment, mechanical design, vacuum coating, etching, and semiconductor-type lithography. Commercial Applications and Other Benefits: Windows will enable high resolution spectroscopy with advanced detectors at DOE user facilities. The new windows will enhance the measurement capability of current commercial instrumentation with increasingly large detectors. Future applications for the windows will be for detectors having increased sensitivity to identify trace organic phases, characterize microelectronic and nanofabricated components, and perform X-ray science. The innovation will improve capabilities in forensic science, nuclear forensics and X-ray astronomy.