Low temp problems

u6144414 at ucsvc.ucs.unimelb.edu.au u6144414 at ucsvc.ucs.unimelb.edu.au
Tue Oct 10 07:11:22 EST 1995


>We are currently have severe icing problems with the MSC low temperature
>  Additionally, if you have any experience with the Oxford
>Cryostream or the new X-stream from MSC, we would appreciate hearing from
>you, especially if you are experiencing NO icing problems.  Replacing
>the MSC unit with one of these systems (or any other) is an option.

     We have had an Oxford Cryostream on each of our two Enraf-Nonius CAD4
single crystal diffractometers for over 2 1/2 years. We have had no 
problems with these units.  We regularly do data collections at 100-130 K
for up to 2 weeks.  Icing is no problem, minimal to non-existent.  They 
are simple to use. Each comes with a Dry air unit so there is only one 
temperature gradient: 
               ambient temp | ambient temp | cold N2 gas
                  Lab air   | Dry air      |

     Operation:  Press a few buttons to set temperature, cooling rate, etc.
and adjust Dry air flow rate to match N2 flow rate.
     As far as maintenence is concerned - Minimal.  After about 18 months of 
use both needed the vacuum insulation space re-evacuated, using a rotary
vacuum pump. Takes about a day. if everything is set up.
     Nitrogen usage: about 0.6 litre/hour, from an open Dewar.  We use
30 litre dewars and usually top them up once a day when they are still 
about half full. Friday night to sunday morning has been succesfully 
tried on a couple of occasions.
     I have never (sucessfully) used anything else.  I don't want to (unless
it is as good as this). I would certainly recommend this option. I don't 
know anything about X-stream.

Dr. Robert W. Gable,               E-mail:   U6144414 at ucsvc.ucs.unimelb.edu.au
School of Chemistry,               Phone:    +61 3 9344 7145
University of Melbourne,           Fax:      +61 3 9347 5180
Parkville, Victoria 3052.

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