Siemens LT2 cryostat
hhope at ucdavis.edu
Fri Nov 10 23:53:58 EST 1995
When I first set up a Siemens LT-2, I had the same problem.
You are probably correct in thinking that the nozzle does not
give you a laminar flow. I solved the problem as follows:
First I acquired these materials: a 3 inch (approx) long piece
of thin-walled plastic tubing of a diameter that fits inside
the nozzle, a package of epoxy putty (Mastermend, found in
auto supply stores).
I then inserted the tube into the nozzle, from the outlet end.
With a short piece of the tube sticking out I packed the space
between the nozzle and the tube with the epoxy putty, pushed
the tube flush with the nozzle end, and let the putty harden.
This modification changed the nozzle from useless to quite
good. It is not necessary to use a special enclosure. Even
though summers are very dry here, winters can be as wet as
anybody's winters. We do not have icing at all.
The main problem with the Siemens nozzle is that it is too
wide. The crystal mounting pin also plays a crucial role.
If you need additional information, just let me know.
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