Image intensifier gain uniformity improvements in sealed tubes by selective scrubbing

Patent · Sun Jan 01 00:00:00 EST 1995

OSTI ID:869841

Thomas, Stanley W ^[1]

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1. Livermore, CA

The gain uniformity of sealed microchannel plate image intensifiers (MCPIs) is improved by selectively scrubbing the high gain sections with a controlled bright light source. Using the premise that ions returning to the cathode from the microchannel plate (MCP) damage the cathode and reduce its sensitivity, a HeNe laser beam light source is raster scanned across the cathode of a microchannel plate image intensifier (MCPI) tube. Cathode current is monitored and when it exceeds a preset threshold, the sweep rate is decreased 1000 times, giving 1000 times the exposure to cathode areas with sensitivity greater than the threshold. The threshold is set at the cathode current corresponding to the lowest sensitivity in the active cathode area so that sensitivity of the entire cathode is reduced to this level. This process reduces tube gain by between 10% and 30% in the high gain areas while gain reduction in low gain areas is negligible.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• DOE Contract Number: W-7405-ENG-48
• Assignee: Regents of University of California (Oakland, CA)
• Patent Number(s): US 5408087
• OSTI ID: 869841
• Country of Publication: United States
• Language: English

Related Subjects

image
intensifier
uniformity
improvements
sealed
tubes
selective
scrubbing
microchannel
plate
intensifiers
mcpis
improved
selectively
sections
controlled
bright
light
source
premise
returning
cathode
mcp
damage
reduce
sensitivity
hene
laser
beam
raster
scanned
mcpi
tube
current
monitored
exceeds
preset
threshold
sweep
rate
decreased
1000
times
giving
exposure
set
corresponding
lowest
active
entire
reduced
level
process
reduces
10
30
reduction
negligible
channel plate
image intensifier
light source
laser beam
microchannel plate
cathode current
beam light
active cathode
plate image
raster scan
raster scanned
image intensifiers
set threshold
bright light
/250/