CCD on-chip gain vs temperature

[Paul.Jorden at eev.com]

Posted to CCD-world:
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Ken et al,

 > I am looking for any information or indication if CCD on-chip gain 
(electrons
 > to
 > volt conversion factor) changes with temperature.  I thought I would ask 
here
 > first
 > before doing any tests myself.  It the gain can change with temperature,
 > presumably
 > it would be due to any temperature sensitivity of the output node 
capacitance.
 > Also, is there any mechanism that would cause the QE to change with
 > temperature ?
 >
By coincidence, I have just measured the gain of a test-chip (EEV CCD47-10) 
at two temperatures:
at -60 C  gain= 21.5 (e/digital unit)
at -40 C  gain= 21.8
Since the electronic system did not change in this interval, I assume this 
gives an indication of the on-chip gain change.  It is hardly a systematic 
calibration, but maybe it gives some idea.
The general expectation is that gain is not a strong function of 
temperature, but I wouldn't say you could extrapolate this single pair of 
measurements to all temperatures!  Also, devices from other sources could be 
different.

The QE question is too complex to give a simple answer.  Certainly there is 
a drop in response with temperature at the longest wavelengths- especially 
in the 1 um region.

Regards,
Paul
_______________________________________________________________
Dr Paul Jorden,  CCD Sensors, EEV
Waterhouse Lane, Chelmsford, Essex, CM1 2QU, UK
Tel:      44 (0) 1245 -453458 (direct), -493493 (switchboard)
Fax:      44 (0) 1245 453224
see also:-     http://www.ccd.eev.com/

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