Background Rates of Gain Amplifying Detectors in Space

Friday, 18 December 2015
Poster Hall (Moscone South)
Elizabeth MacDonald1, Levon A Avanov1, Ulrik Gliese1, Craig J Pollock2, Barbara L Giles1, Herbert O Funsten3, Brian Larsen4, Ruth M Skoug5, Daniel J Gershman6, Alexander C Barrie7, Victoria N Coffey8, Michael O Chandler8, Barry Mauk9, John Dorelli1 and Amy Catherine Rager10, (1)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (2)NASA Goddard Space Flight Center, Heliophysics Sci. Div., Greenbelt, MD, United States, (3)Los Alamos Natl Laboratory, Los Alamos, NM, United States, (4)The New Mexico Consortium, Los Alamos, NM, United States, (5)Los Alamos Natl Lab, Los Alamos, NM, United States, (6)NASA Goddard Space Flight Center, Solar System Exploration Division, Greenbelt, MD, United States, (7)NASA Goddard Space Flight Center, (SGT Inc.), Greenbelt, MD, United States, (8)NASA Marshall Space Flight Center, Huntsville, AL, United States, (9)Applied Physics Laboratory Johns Hopkins, Laurel, MD, United States, (10)Catholic University of America, Physics, Washington, DC, United States
In the near Earth space environment plasma instruments utilize gain multiplying detectors such as microchannel plates (MCPs) or channel electron multipliers (CEMs) to amplify single impacting particles into countable electronic pulses. These detectors also respond to higher energy particles such as penetrating MeV electron and proton radiation. Such background signals can be significant enough to be confused with foreground signals of interest in environments like Earth or Jovian radiation belts. It is thus critically important to fully understand the sensitivity of MCP and CEM detectors in situ. In the lab, MCPs are estimated to be ~ 20 times more sensitive per unit input area than CEMs. We will compare the background rates for two recent instruments, the Helium Oxygen Proton Electron (HOPE) mass spectrometer for the Van Allen Probes, and the Fast Plasma Investigation (FPI) instrument suite on the Magnetospheric Multiscale Mission to their respective penetrating radiation environment and estimate the relative response rates for these two types of detectors.