Persistence: Theory and Practice
Mike Regan
Eddie Bergeron
Kevin Lindsay
Doug Long
Experiment Setup
Single Long Exposure
Initial reset
10 Short Exposures
Resets during final
write to disk
Write to disk and Resets at beginning of each exposure
The total persistence in an up-theramp,100 dark (1060 seconds) after the
bright exposure.
The persistence in the single long exposure
is 2.3 time that of the 10 short exposures.
Changing the detector substrate bias yields a
dark image that looks just like persistence.
Photons captured in the depletion region
yield an electron/hole pair.
Roger Smith’s Model
As charge accumulates the depletion
region gets smaller.
After a reset trapped electrons and
holes are left in the depletion region.
During the next exposure the electrons/holes
decay from the traps and are seen as a change in
the voltage.
Each persistence electron/hole generates less voltage than a
photoelectron/hole.
Reset mode does not affect persistence.
QuickTime™ and a
TIFF (U ncompressed) decompressor
are needed to see this picture.
The return of persistence after the
reset!?
Conclusions
• The more charge that accumulates the
more the persistence.
• Reset mode does not affect
persistence.
• The Smith model explains most of the
observations [but not all].