High Speed Large Format Photon Counting Microchannel Plate Imaging Sensors

High Speed Large Format Photon Counting Microchannel Plate Imaging Sensors


Siegmund, O. H. W., Ertley, C., Vallerga, J. V., Craven, C. A., Popecki, M. A., O’Mahony, A., & Minot, M. J. (Year). High speed large format photon counting microchannel plate imaging sensors. In Name of Conference Proceedings (pp. page numbers). 


  • Microchannel plate
  • photon counting
  • imaging
  • timing


Atomic layer deposition (ALD) is enabling the development of large, stable microchannel plate (MCP) detectors for applications ranging from astronomy and remote sensing to biological imaging and high energy physics. 


This article discusses a new class of microchannel plate (MCP) technology for use in photon counting imaging sensors. These new MCPs use atomic layer deposition (ALD) techniques on a borosilicate microcapillary array to improve upon the performance and size limitations of conventional MCPs.

Performance Improvements of ALD MCPs Over Conventional MCPs:

  • ALD MCPs offer improved lifetime and gain stability.
  • ALD MCPs have reduced background levels.
  • The borosilicate glass used in ALD MCPs contains less radioactive material than standard MCP glass.

Advantages of ALD MCPs:

  • ALD MCPs can be much larger than conventional MCPs, with formats of 20cm or more achievable.
  • ALD MCPs are very robust due to the resilience and high temperature properties of the borosilicate substrate material.
  • The ALD process allows the creation of MCPs with a curved surface, which could be useful for matching instrument focal planes that are cylindrical or spherical.

Tests of ALD MCP Performance:

The authors conducted tests of ALD MCPs in various formats and configurations, and some of their findings are summarized below:

  • Tests of 33 mm and 20 cm ALD MCPs showed that the gain, pulse amplitude distribution, and resistance of ALD MCPs are similar to those of conventional MCPs.
  • ALD MCPs showed high gain, with the gains with 20 cm ALD MCP pairs reaching 107 or greater.
  • Background rates for ALD MCPs were found to be very low, about 0.028 events cm-2 sec-1, which is comparable to the expected rate from cosmic ray muons.
  • Tests using a 20 cm ALD MCP triplet showed a spatial resolution of about 60 µm FWHM.
  • ALD MCPs may have a lower sensitivity to penetrating radiation than conventional MCPs. For instance, tests suggest the detection efficiency of ~1 MeV gamma rays by 2nd generation borosilicate ALD MCPs could be as low as 0.25%.

Applications of ALD MCPs

  • The authors created two sealed tubes to test ALD MCPs, one with a GaN photocathode and one with a standard bialkali photocathode.
  • They are also part of a collaboration to create a 20 cm square format sealed tube detector.

 Origin: https://amostech.com/TechnicalPapers/2015/Poster/Siegmund.pdf

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