Count Rate Performance of a Microchannel Plate Photomultiplier


The article focuses on the rate-dependent gain change of a micro-channel plate photomultiplier.
This research was supported by the U.S. Department of Energy under contract number DE-AC07-761101570.
The authors of the article acknowledge L.O. Johnson for technical discussions and Eunice Rahl for manuscript production.


  • Microchannel plate photomultiplier (MCPP)
  • Gain change
  • Counting rate
  • Pulse saturation mode
  • Scintillation detector
  • NaI(T1) scintillator
  • Gain recovery time
  • Inter-dynode gain
  • Quantum efficiency
  • Electron open area ratio


The information provided in the source does not contain a summary of the article. However, the source does indicate that the article focuses on measuring the rate-dependent gain change of a microchannel plate photomultiplier.


This article investigates how the gain of a microchannel plate photomultiplier (MCPP) changes depending on the counting rate. The authors found that the gain of the MCPP can change by up to 60% at high counting rates. They observed this phenomenon while using the MCPP in a scintillation detector system with NaI(T1) as the scintillator. The cause of these gain changes is likely the high resistivity of the materials used to make the MCPP.

How the Study Was Conducted:

  • The researchers used both 22Na and 137Cs radiation sources in their experiments.
  • They controlled interaction rates by adjusting the distance between the radiation source and the detector.
  • A 0.63 cm thick lucite absorber was placed between the source and detector to prevent X-ray interactions within the scintillator.
  • The team used a NaI(T1) crystal as the scintillator.
  • The MCPP used was a 1TT Model F4129 with a single anode, bialkali cathode, and a Z-plate configuration with 1.3 x 10^7 channels.

Empirical Model:
The authors developed an empirical model to calculate gain changes as a function of channel use rate. The model utilizes information provided by MCPP manufacturers. The model effectively predicts gain changes at channel use rates (R) below 500 s^-1.


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