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Detector Technologies for Ultraviolet (UV), X-Ray, and Gamma-Ray Instruments


Scope Title:


Scope Description:

This subtopic covers detector requirements for a broad range of wavelengths from ultraviolet (UV) through to gamma ray for applications primarily in astrophysics, heliophysics, and planetary science; and also to Earth science. Requirements across the board are for greater numbers of readout pixels, lower power, faster readout rates, greater quantum efficiency, single photon counting, and enhanced energy resolution. The proposed efforts must be directly linked to a requirement for a NASA mission. These include Explorers, Discovery, Cosmic Origins, Physics of the Cosmos, Solar-Terrestrial Probes, Vision Missions, and Earth Science Decadal Survey missions. Additive manufacturing of interconnect technology development requested here is a science enabling technology for the next strategic-class astrophysics mission infrared/optical/ultraviolet (IROUV) that has been recommended by the 2020 Astrophysics Decadal Survey. Proposals should reference current NASA missions and mission concepts where relevant. Specific technology areas are:

  • Large-format, high-resolution focal plane arrays: Desired features include 8k x 8k, three-side buttable; pixel size: <~7 µm; read noise: ~1 e- rms; dark signal ~1x10-4 e-/pixel/s; operating temperature >150 K; radiation hard.
  • Large-format, low-dark-rate, high-efficiency, photon-counting, solar-blind, far- and near-UV detectors: Desired features include at least 100x100 mm2 formats with <25 µm resolution elements, flat-field uniformity <10% across face, low-power-consumption-anode readout electronics, immunity to gain sag, high photon-counting rates (> 107 counts/s), low dark (<<1 count/cm2/s); quantum efficiency (QE) >30% between 100 and 200 nm; solar blind; radiation hard.
  • High-dynamic-range, high-efficiency detectors in UV/O/NIR, narrowband (UV only), and broadband (UV to NIR (near IR)).
  • Solid-state detectors with polarization sensitivity relevant to astrophysics as well as planetary and Earth science applications; for example, in spectropolarimetry as well as air quality and aerosol monitoring and for O3, NO2, SO2, H2S, and ash detection. Refer to National Research Council's Earth Science Decadal Survey (2018).
  • Significant improvement in wide-band-gap semiconductor materials (such as AlGaN, ZnMgO, and SiC), individual detectors, and detector arrays for astrophysics missions and planetary science composition measurements. For example, SiC avalanche photodiodes (APDs) must show:
    • Extreme-UV (EUV) photon counting, a linear mode gain >10×106 at a breakdown reverse voltage between 80 and 100 V.
    • Detection capability of better than 6 photons/pixel/s down to 135 nm wavelength.
  • Solar-blind (visible-blind) UV, far-UV (80 to 200 nm), and EUV sensor technology with high pixel resolution, large format, high sensitivity and high dynamic range, and low voltage and power requirements—with or without photon counting.
  • Solar x-ray detectors with small independent pixels (10,000 count/s/pixel) over an energy range from <5 to 300 keV.
  • Supporting technologies that would help enable the x-ray Surveyor mission that requires the development of x-ray microcalorimeter arrays with much larger field of view, ~105 to 106 pixels, of pitch ~25 to 100 μm, and ways to read out the signals. For example, modular superconducting magnetic shielding is sought that can be extended to enclose a full-scale focal plane array. All joints between segments of the shielding enclosure must also be superconducting. Improved long-wavelength blocking filters are needed for large-area, x-ray microcalorimeters.
  • Novel concepts for improving superconducting magnetic shielding such as superconducting inks or additive manufacturing are of interest for detector focal planes with challenging shielding geometries and other requirements.
  • Filters with supporting grids are sought that, in addition to increasing filter strength, also enhance electromagnetic interference (EMI) shielding (1 to 10 GHz) and thermal uniformity for decontamination heating. x-ray transmission of greater than 80% at 600 eV per filter is sought, with IR transmission of less than 0.01% and UV transmission of less than 5% per filter. A means of producing filter diameters as large as 10 cm should be considered.
  • Detectors with fast readout that can support high count rates and large incident flux from the EUV and x-rays for heliophysics applications, especially solar-flare measurements.
  • Supporting technologies for packaging of UV detector focal planes with suitable device interfaces (such as microshutter arrays) including additive manufacturing of electronics (AME) of conductive materials to create high-density, well-isolated interconnects in fine feature sizes (down to 50 µm wide on planar substrates that include up to a 1.5-mm sidewall). In NASA 2022 Astrophysics Strategic Technology Gaps, see gap "High Throughput, Large-Format Object Selection Technologies for Multi-Object and Integral Field Spectroscopy."


Expected TRL or TRL Range at completion of the Project: 3 to 5

Primary Technology Taxonomy:

  • Level 1 08 Sensors and Instruments
  • Level 2 08.1 Remote Sensing Instruments/Sensors

Desired Deliverables of Phase I and Phase II:

  • Research
  • Analysis
  • Prototype
  • Hardware

Desired Deliverables Description:

Phase I deliverables: results of tests and analysis of designs, as described in a final report. 

Phase II deliverables: prototype hardware or hardware for further testing and evaluation is desired.

State of the Art and Critical Gaps:

This subtopic aims to develop and advance detector technologies focused on UV, x-ray, and gamma-ray spectral ranges. The science needs in this range span a number of fields, focusing on astrophysics, planetary science, and UV heliophysics. A number of solid-state detector technologies promise to surpass the traditional image-tube-based detectors. Silicon-based detectors leverage enormous investments and promise high-performance detectors, and more complex materials such as gallium nitride and silicon carbide offer intrinsic solar-blind response. This subtopic supports efforts to advance technologies that significantly improve the efficiency, dynamic range, noise, radiation tolerance, spectral selectivity, reliability, and manufacturability in detectors.

Relevance / Science Traceability:

NASA Science Mission Directorate (SMD) applications:


Missions under study (Large Ultraviolet Optical Infrared Surveyor (LUVOIR), Habitable Exoplanet Observatory (HabEx), Lynx, and New Frontiers-Io Observer):

  • LUVOIR—Large UV/Optical/IR Surveyor:
  • Habitable Exoplanet Observatory (HabEx):
  • The LYNX Mission Concept:
  • Lunar Science/Missions: UV spectroscopy to understand Lunar water cycle and minerology (water detection using edge at 165 nm, H2 at 121.6 nm, and OH- at 308 nm), LRO-LAMP (Lyman Alpha Mapping Project).
  • Gravitational Wave Science: Swift detection of x-ray and UV counterparts of gravitation wave sources.
  • Planetary Science: Europa Clipper (water/plume detection), Enceladus, Venus (sulfur lines in the 140 to 300 nm range).
  • Earth Science: ozone mapping, pollution studies.


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