Overheat temp. switches

[Olaf Iwert]

Dear all,

Here it goes with yet another request :

As many others we would like to increase the heating power inside the cryostat 
head to heat the CCD. This proves to be useful for maintenance, faster warm-up
and clean cryo conditions as needed e.g. for UV flooding.

However one problem can be to provide a lot of heating power without a 
hardware safety device against potential overheating of the CCD inside the 
dewar. (I know we can have precautions in the software such as temperature 
sensor contact loss detection etc., but an additional hardware protection 
seems more than useful to me in view of the charcaterization time, budget and 
replacement constraints for CCD devices).

My question is whether anyone knows and has tested such a device which is :
a.) small
b.) reliable
c.) suitable for vacuum
d.) still works at and withstands the N2 temperature
e.) obtainable for different temperature switch points (e.g. +70,+90,+120 C) 
f.) self repairing (not like a fuse one has to replace, breaking the vacuum)

????????????

In case you would even have a data sheet, I'd be more than happy to receive 
a copy of that via fax, as this would enable me to evaluate all the mechanical
things asap..... 




Thanks a lot

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  Olaf Iwert                        E-mail :               oiwert at eso.org  
  European Southern Observatory     Phone & Voice Mail :   +49-89-320-06-353  
  Optical Detector Lab              FAX :                  +49-89-320-23-62
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  GERMANY                         
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