Maximizing the quantum efficiency of microchannel plate detectors: the collection of photoelectrons from the interchannel web using an electric field

Journal Article · Tue Feb 01 04:00:00 EST 1983 · Rev. Sci. Instrum.; (United States)

DOI:https://doi.org/10.1063/1.1137365· OSTI ID:6535104

Taylor, R C; Hettrick, M C; Malina, R F

We report dependence of the extreme ultraviolet quantum efficiency (QE) of a microchannel plate (MCP) detector upon the electric field strength above its input face. Using an uncoated plate, we measured increases up to 80% as the field was raised from 0 V/..mu.. to between 0.01 and 0.1 V/..mu... Further increases in electric field resulted in a monotonic decrease in QE. Detector spatial resolution was found to degrade for these small field values but could be recovered, while maintaining most of the QE increase, by operating with fields in excess of 0.3 V/..mu... Other detector parameters such as modal gain and output charge pulse-height distribution were not significantly affected by the applied electric field. We explain the QE and resolution variations in terms of photoelectrons ejected from the interchannel web and subsequently returned to the input face of the MCP by the applied electric field. We present a model and a computer simulation which quantitatively reproduce our experimental results. Applying our model to MCPs coated with photocathode materials, we conclude that the maximum QE is obtained by optimizing the combined contributions from the web area and open area of the MCP, rather than by maximizing the open area alone. In this case, most of the QE can arise from the interchannel web rather than from the directly illuminated channels.

• Research Organization: Space Sciences Laboratory, University of California, Berkeley, California 94720
• OSTI ID: 6535104
• Journal Information: Rev. Sci. Instrum.; (United States), Journal Name: Rev. Sci. Instrum.; (United States) Vol. 54:2; ISSN RSINA
• Country of Publication: United States
• Language: English

Related Subjects

440101* -- Radiation Instrumentation-- General Detectors or Monitors & Radiometric Instruments
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
AMPLIFICATION
CATHODES
CHARGE COLLECTION
COMPUTERIZED SIMULATION
EFFICIENCY
ELECTRIC FIELDS
ELECTRODES
ELECTROMAGNETIC RADIATION
ELECTRON MULTIPLIERS
ELECTRON TUBES
ELECTRONS
ELEMENTARY PARTICLES
FAR ULTRAVIOLET RADIATION
FERMIONS
GAIN
GRIDS
LEPTONS
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
MICROCHANNEL ELECTRON MULTIPLIERS
OPTIMIZATION
PHOTOCATHODES
PLATES
QUANTUM EFFICIENCY
RADIATION DETECTORS
RADIATIONS
RESOLUTION
SIMULATION
SPATIAL RESOLUTION
ULTRAVIOLET RADIATION