Getters/Molecular Sieves

[Paddy Oates]

Tim,
	Hi, we use  charcoal from Oxford Inst. in the dewars. As you may recall 
we had a problem with vacuum grease contamination in one of our instruments 
recently and as a precaution I replaced the getter material . It has a rod-like 
appearance, a few mm long, 1mm or is dia. and VERY prone to respond to any 
static so it can be difficult to get it in the place you want it without some 
care. We bake the material out for an hour or so - all our getters have heaters 
in them, whilst pumping at room temp.
We dont use powder. I have a feeling this stuff DIDNT help in absorbing the 
vacuum grease.... it was quite a long way from the source of the problem 
though.  The getters are mounted right on the Copper cans inside the dewars.



Cheers 
Paddy

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