Microchannel plate (MCP) detectors with cross strip (XS) readouts are powerful sensor technologies that when migrated to high TRL can satisfy the demands for many future NASA missions. Through…

The University of California, Berkeley received a $1.17 million research grant from NASA (awarded February 15, 2022, with completion targeted for February 14, 2027) to advance microchannel plate (MCP) detector technology with cross-strip (XS) readout systems for future space missions. The project focuses on developing a multi-channel application-specific integrated circuit (ASIC) to improve upon earlier prototypes, specifically addressing power consumption challenges that currently limit deployment on large-format detectors required for missions such as LUVOIR and HabEx, as well as power-constrained platforms like CubeSats. MCPs with XS readouts offer significant advantages for ultraviolet sensing, including single-photon position encoding, reduced voltage requirements, extended sensor lifetime, and high spatial resolution (100 micrometers, exceeding 5,000 by 5,000 resels) while operating at ambient temperatures with minimal dark count rates.

This award represents a continuation of prior Small Activity Technology (SAT) efforts at UC Berkeley to mature MCP detector technology to higher technology readiness levels. The initiative builds on successful development of a prototype ASIC known as the GRAPH device, whose early benchtop and detector test results have proven encouraging but incomplete. The grant supports further characterization and refinement of this low-power readout system that integrates charge amplification and signal digitization into a single device, moving the detector technology closer to operational capability for NASA's future astronomical and space exploration missions. No set-aside designation was applied to this competitively awarded grant.

Microchannel plate (MCP) detectors with cross strip (XS) readouts are powerful sensor technologies that when migrated to high TRL can satisfy the demands for many future NASA missions. Through previous SAT efforts we have built both open face and sealed tube XS readout detectors that have high performance and environmental robustness. Mcps and photocathodes provide UV sensing and electronic signal amplification, while the XS readout accomplishes single photon position encoding using charge cloud centroiding. XS readouts allow MCP operation at amplification gains much lower than prior methods (factors of ~20 less), reducing the voltage requirements for the mcps, increasing local and global event rates, and greatly extending the sensor usable lifetime. Such detectors have demonstrated high spatial resolution (100 MM, > 5K 5K resels) with focal plane curvature matching. The mcps also operate at ambient temperatures with very low dark count rates of ~0.04 events/SEC/CM2. The current generation of XS readout electronics employ separate electronic modules to perform the amplification of the XS signals, their fast digitization and for subsequent fpga event position encoding. While these electronics can meet the needs of future missions for resolution and counting rates, they do not meet the needs with regards to total system power when scaled to the large format detectors required by luvoir or habex, or for missions (cubesats, etc.) which have constraints on their power budget. The path forward to achieve substantial power reduction is a readout system based on a multi-channel application specific integrated circuit (asic) which combines the charge amplification and signal digitization into a single, low power device. In a previous SAT grant, we successfully developed a first version of this device, the graph asic, and performed some initial characterization of its performance. Early benchtop and detector test results from this device are encouraging but incomplete. In this project, we will partner with nalu scientific (asic development experts who worked on the graph device). We propose to complete full characterization of the current graph device and use the information learned to optimize the design of the chip. We anticipate a foundry run on a next generation device (GRAPH2), which we would then fully characterize. The next step is development of custom electronics boards for the GRAPH2 device, and implementation of fpga firmware to process the data from the GRAPH2 device to produce photon position data. Subsequent effort would then be to integrate this with existing XS MCP detectors, both open face and sealed tube, to optimize performance, and finally perform environmental tests to qualify the XS system and elevate its TRL to readiness for flight programs. Large area MCP detectors are part of the baseline plan for UV instruments on two of the large mission concepts being considered in the national academy of sciences astronomy and astrophysics decadal survey (ASTRO2020). The large ultraviolet/optical/infrared surveyor (luvoir) ultraviolet multi-object spectrograph (lumos) and the ultraviolet spectrograph on the habitable exoplanet observatory (habex-UVS) will provide improvements in high sensitivity spectroscopy, astrometry, angular resolution, and wavelength coverage. To achieve their science goals, both missions will require large, radiation hard UV detectors (>100 100 MM2) with 20 m resolution elements, high quantum efficiency, > 5 MHZ global rate capability, ~100 HZ maximum local rates and very low in-situ detector background rates. Furthermore, a variety of potential explorer and probe (e.g., cosmic evolution through UV spectroscopy - cetus) class missions would have their science enabled and potentially greatly enhanced by the availability of advanced XS detectors.