CCD-world: dark signal level

[MYPIXEL at aol.com]

The following was posted to CCD-world:

In a message dated 10/19/99 5:03:47 AM EST, Jenichen at proscan.de writes:

<< Which types of CCD do You use? On Which level is Your information based?
 Normally the nonuniformity is caused by not very uniform cooling and by
 the extensive use of the output amplifiers (as fast as they work,
 without reserve so they heat from one side). Nevertheless the
 nonuniformity should be better than 10%. >>

**************************jj

We were referring to pixel to pixel thermally generated dark current 
nonunformity. As you point out, there are many other generators of dark 
current (luminescence of many flavors, spurious charge, cosmic rays, excess 
charge, dark spikes, light leak, black body, etc.). They can add to the 
nonunformity measured (rms) when a dark frame is taken. But, these sources 
can be isolated where thermal dark current nonuniformity can be measured. 
About 10 % (100 x noise/signal).

I'm curious about dark current being generated by your amplifier. Are you 
sure the source isn't luminescence? The problem is common with dual stage 
amplifiers where on-chip load MOSFETs are ultilized. Also, non LDD CCD amps 
exhibit the problem because of low breakdown characteristics. What sensor are 
you using?

What sensors do we use? Best answer on this is "all of the above."

Don't know what you mean by "On Which level is Your information based?" Can 
you re ask this question?

******************************jj
- -- CCD-world -- --
CCD-world is fully moderated. Send posts to CCD-world at astro.ku.dk
Standard replies will go to the list; address personal replies manually.
For more information, please go to:  http://www.not.iac.es/CCD-world/