Comparative Response of Microchannel Plate and Channel Electron Multiplier Detectors to Penetrating Radiation in Space

Journal Article · Fri Oct 02 00:00:00 EDT 2015 · IEEE Transactions on Nuclear Science

DOI:https://doi.org/10.1109/TNS.2015.2464174· OSTI ID:1329562

Funsten, Herbert O. ^[1]; Harper, Ronnie W. ^[2]; Dors, Eric E. ^[3]; Janzen, Paul A. ^[4]; Larsen, Brian A. ^[5]; MacDonald, Elizabeth A. ^[6]; Poston, David I. ^[7]; Ritzau, Stephen M. ^[8]; Skoug, Ruth M. ^[5]; Zurbuchen, Thomas H. ^[9]

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Intelligence and Space Research Division
2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Space Science and Applications Group
3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Emerging Threats Program Office
4. Univ. of Montana, Missoula, MT (United States). Dept. of Physics and Astronomy
5. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Space Science and Applications Group
6. NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States). Sciences and Exploration Directorate
7. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Systems Design and Analysis Group
8. Photonis USA Inc., Sturbridge, MA (United States)
9. Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Atmospheric, Oceanic, and Space Sciences

Channel electron multiplier (CEM) and microchannel plate (MCP) detectors are routinely used in space instrumentation for measurement of space plasmas. Here, our goal is to understand the relative sensitivities of these detectors to penetrating radiation in space, which can generate background counts and shorten detector lifetime. We use 662 keV γ-rays as a proxy for penetrating radiation such as γ-rays, cosmic rays, and high-energy electrons and protons that are ubiquitous in the space environment. We find that MCP detectors are ~20 times more sensitive to 662 keV γ-rays than CEM detectors. This is attributed to the larger total area of multiplication channels in an MCP detector that is sensitive to electronic excitation and ionization resulting from the interaction of penetrating radiation with the detector material. In contrast to the CEM detector, whose quantum efficiency ε_γ for 662 keVγ -rays is found to be 0.00175 and largely independent of detector bias, the quantum efficiency of the MCP detector is strongly dependent on the detector bias, with a power law index of 5.5. Lastly, background counts in MCP detectors from penetrating radiation can be reduced using MCP geometries with higher pitch and smaller channel diameter.

• Research Organization: Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE Laboratory Directed Research and Development (LDRD) Program
• Grant/Contract Number: AC52-06NA25396
• OSTI ID: 1329562
• Report Number(s): LA-UR-15-20916
• Journal Information: IEEE Transactions on Nuclear Science, Vol. 62, Issue 5; ISSN 0018-9499
• Publisher: Institute of Electrical and Electronics Engineers (IEEE)
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
Astronomy and Astrophysics
Heliospheric and Magnetospheric Physics
Electron multipliers
Gamma-ray effects
Plasma measurements
Radiation effects