Getters/Molecular Sieves

[Craig D Mackay]

Dear Tim/All

We use the getters that the dewar manufacturers use, activated charcoal. 
  Zeolite is good for water usually but you can get it in various pore 
sizes (for different molecular scales).   We use zeolite as a powerful 
dessicant in out thermoelectric heads, and it is excellent at that, 
though you really need to prepare it well.   That would be an objection, 
I think to zeolites for a LN getter since they need a jolly good cooking 
to work at their best whereas you can heat charcoal to a lower 
temperature to get it back in gear.

Rather unquantitative and anecdotal, but what do you expect with CCDs?

Best Wishes

Craig D Mackay
Institute of Astronomy
University of Cambridge

and AstroCam Ltd