Hi Charles
I had 4 inches ConFlat UV grade viewports from Verre Métal in France for
700 US$. Probably someone else does that cheaper !
Although they are slightly thicker (about 2 mm) they seem not to disturb
too much the focus of the alser (mine focusses to about 10 microns despite
the thickness).
I also found low blanks despite the surface of the viewport.
Nick Arnaud
At 08:49 21/05/01 -0500, you wrote:
>Greetings Simon,
>We have used various viewports. As you know quartz viewports leak Helium
>rather badly through the quartz itself. We have also found that at Neon
>leaks through quartz viewports as well (at a very low rate, but sufficient
>to dominate our blank for laser extracted Ne from micron-sized
>grains). For He and Ne laser work we had to go to sapphire ports.
>
>By the way. does anybody know a good source for UV grade sapphire ports
>larger than 1 inch diameter (on 2 3/4 or 4 inch ConFlats)?
>
>Charles Hohenberg
>
>
>*******************************
>
>At 08:26 AM 5/21/2001 +0100, you wrote:
>>I expected this noble-gas-network list to be quiet for a while as people
>>joined and didn't post because they didn't know if many others had joined.
>>I was wrong, 60 people world-wide joined in the first 3 days, and started to
>>post, so your postings are now being read by many of your colleagues.
>>
>>Hi James,
>>
>>Jo-Anne Wartho and I had a similar problem with quartz viewports a while
>>ago, ours were supplied by Caburn-MDC. The company couldn't detect the leak
>>when we returned the port and in fact we eventually found it was a virtual
>>leak. It turned out that they were welding in a noble gas, so we had to
>>have viewports made for helium work and a separate set made for argon work.
>>The gas was leaking from the weld not from the outside ! This may not be
>>your problem but if you still have it, check if your viewport leaks for both
>>argon and helium.
>>
>>Simon.
>>
>>----------------------------------------------------------------------------
>>----------------------------------
>>Simon P. Kelley
>>Department of Earth Sciences
>>Open University
>>Milton Keynes
>>MK7 6AA
>>Tel: +44 1908 653009
>>FAX: +44 1908 655151
>>Email: [log in to unmask]
>>Departmental Web page: http://exodus.open.ac.uk/index.html
>>----------------------------------------------------------------------------
>>---------------------------------
___________________________________________________________________________
Dr Nicolas ARNAUD, PhD UMR 6524 CNRS
Chargé de recherche CNRS Lab. "Magmas et Volcans"
Tel: (33 0) 473 34 67 11 5 rue Kessler
Fax: (33 0) 473 34 67 44 63000 Clermont-Ferrand France
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