Microchannel plate detectors for future NASA UV observatories

Abstract

Microchannel plate sensors are widely used as photon counting imagers in many applications, including, astronomy, high energy physics, and remote sensing. Potential future NASA observatories with ultraviolet instruments, such as LUVOIR and HABEX, will require large area detectors (8k × 8k pixels) with large dynamic range (≥1 kHz/resel), high quantum efficiency (75% peak), and very low backgrounds (≤0.1 cts/sec/cm2 ). New microchannel plate technology combining borosilicate glass microcapillary arrays with high efficiency materials applied by atomic layer deposition are being developed with these goals in mind. Detectors with these microchannel plates can be made in large formats (up to 400 cm2 ) with focal plane matching, have high spatial resolution ( 110 nm range). New photocathodes, such as GaN and hybrid bialkali/alkali halide, have high quantum efficiencies over broadband wavelengths. Cross-strip anodes are well suited for large format detectors with high spatial resolution and high dynamic range requirements. Improvements to detector anodes and readout electronics have resulted in better spatial resolution (10×), output event rate (100×), and temporal resolution (1000×), all the while operating at lower gain (10×). Combining these developments can have a significant impact to potential future NASA sub-orbital and satellite instruments.