Measurements have been made to determine the characteristics of high amplitude events in microchannel plates (MCP‘s). The background pulse amplitude spectrum is found to extend to 30x the MCP modal gain. The majority of the background events are initiated by 40K beta decay in the MCP glass. However, up to 4% of the events are due to cosmic ray events. Comparison of background pulse amplitude spectra for horizontal, and vertical MCP orientations suggests that the largest events are predominantly cosmic ray induced. Anticoincidence measurements confirm this result. A model describing the 40K beta decay and cosmic ray interactions in the MCP predicts spectra in accord with these observations. We have also determined the response of MCP's when subjected to simultaneous multiphoton input. This shows that pulse amplitudes many times the modal gain are possible even though the response becomes nonlinear at high amplitudes.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics
- Nuclear Energy and Engineering
- Electrical and Electronic Engineering