Getters/Molecular Sieves

[Tim Abbott]

Can I initiate a quick survey:

What getters/molecular sieves (eg. charcoal, zeolite) do you use in 
your dewars and why (i.e. what contaminants are they good at adsorbing)?

Our answer: we use charcoal, but it's not clear to me whether this is best
for sweeping up water vapour &/or hydrocarbons (plus, it makes this nasty
black powder...).

Does anyone have an authoritative word?

Thanks,

	Tim


-- 
Timothy M. C. Abbott                http://www.cfht.hawaii.edu/~tmca/tmca.html