Re: AW: CMOS inquiry for camera gurus

Posted by Alan Mullan on
URL: http://confocal-microscopy-list.275.s1.nabble.com/CMOS-inquiry-for-camera-gurus-tp7589055p7589062.html

*****
To join, leave or search the confocal microscopy listserv, go to:
http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
Post images on http://www.imgur.com and include the link in your posting.
*****

1. I remember hearing a little bit about cameras holding vacuum, but not about this backfill problem. Anyway, what is backfill and how does it go wrong? Is it some kind of an inert, dry gas around the sensor that may now have some moist air in it? How is it possible to get a backfill problem without the seal on the vacuum also breaking? Interestingly, I believe I saw online that the (pre-2016) Andor warranty is 5years on the vacuum and 3years on the backfill.
 
As far as I know (keep in mind that I am from a competitor of Andor) the Zyla is TE cooled but not to an extent that it requires vacuum. Like for the emCCD cameras or the Neo camera. Therefore I guess that one of the seals might have been not as tight as you would prefer it and then it might happen that humidity might enter, which even at an absoluete cooling to 0°C or 5°C can cause condensation. Usually, if you cool but run the camera at normal pressure in the camera head, the head is filled with nitrogen, xenon or argon to keep the humidity out, sometime scavengers are added too.

Hi Josh - just to help clarify what Gerhard has mentioned here regarding backfilling and vacuum and warranties. I agree with the other points he has addressed for you.

The Zyla is like most scientific cameras a "back-filled" camera. The sensor enclosure is filled with an inert gas and then sealed. Over time, all cameras that use this approach will lose the gas over time and when this happens you need to get the camera refilled. Using a camera with condensation will damage the sensor witch would mean a higher cost than just refilling. Andor has a 3 year warranty on the back-fill. Back-filling is a cost-effective way to protect the sensor from condensation however it degrades over time as usually this is done using o-ring seals so this is sometimes not made clear- warranty in some cameras for the back fill can be as low as 12 months. These "back-filled" cameras do not therefore have a vacuum seal.

For this reason Andor have cameras which have permanent vacuum technology (UltraVac). In these models - which are going to be higher performance options at higher price points, the sensor is enclosed and protected in a vacuum with a proprietary vacuum seal. Andor cameras with the vacuum have a warranty for 5 years and for iXon models  it is 7 years. The new Sona back-illuminated sCMOS camera has the UltraVac to ensure there is no need for refilling gas, it maintains the high QE performance over time and allows for deeper cooling if desired.