HEA Technology: X-Ray Sensors

Goals: Many future X-ray astronomy missions will need large focal plane arrays that are well matched to the optical performance of the X-ray telescope. These sensors should provide spatial, temporal, and spectral information at the highest resolution consistent with the mission science goals. For example, the NASA Vision Mission Gen-X includes a large array of microcalorimeters to provide spatially resolved high resolution spectroscopy. There may also be a wide field of view, high spatial resolution active pixel sensor array, to provide the tenth arcsecond angular resolution with more modest spectral resolution and high time resolution. These sensors will need to have long lifetimes and low power consumption, and be robust against catastrophic failure.

To achieve these kinds of performance goals is a challenge. There will be development steps along the way. For example, the calibration of giga-pixel arrays will involve very large data sets that need to be aquired in reasonable time frames and then analyzed. Maintaining microcalorimeters at their low operating temperatures over many years will push the current technology limits. Providing IR, optical and UV rejection without sacrificing low energy X-ray detection efficiency will require new approaches.

Basic approach: The CXT X-ray sensor program is working towards these goals. There is a very active program in microcalorimeter development, particularly in fabricating arrays while maintaining very high energy resolution. CMOS based sensors that can replace X-ray CCDs are being studied. They can be very fast, are naturally radiation hard, and use low power. However, they have higher read noise than CCD's and are subject to pixel-to-pixel cross talk.


Almus Kenter, Ralph Kraft, Suzanne Romaine, Eric Silver, Jon Chappell, Stephen Murray


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