Hi Sikdar,

You can write to oxford scientific directly. 

http://www.oxford-instruments.com/businesses/industrial-products/austin

They are good at low temperature stuffs.

Regards

Sesha

Thank u... Sesha

If the feedthrough is to survive 4K then you might need advice - I'd be inclined to go for a gold seal, rather than a conf-flat flange. But frankly, I've never seen a demountable cryogenic flange that was also UHV rated.

Try Kurt Lesker or MDC Caburn for detailed information.

If I had to tackle this I would probably soft-solder the feed-through in place with Woods metal (stainless steel for the vessel presumably) to ensure a tight seal.

Ok.....

@ James Garry & Lars Petzold ...  Can you recommend the sealing to be used whether conflat flange with metal gasket or with Indium sealing for use in 4K temperature.....Whether conflat flange will work at 4k with metal gasket?

I have no direct experience of 4K vacuum flanges (77K, yes, 4K, no) and so fall back on "Advances in Cryogenic Engineering" by Kitel.

Page 1976 suggests that, conflat copper can be made vacuum tight at 4K.

Oh, hang on! 

{thank you Google}

http://mtm-inc.com/reduce_project_risk/demountable_cryogenic_seal_options/

So.

Indium seems to be the material of choice.

But I'd be inclined to try a standard copper gasket first (much cheaper) and then move to indium if that doesn't hold UHV, Gold wire seal as position of last resort, with soft-soldering as the position right before tossing it all away and starting afresh.

Thanks @ Garry......

Hello

We used feedthroughs mounted on UHV flanges of the regular CF miniconflat type (produced from forged 316LN blanks using OFS copper gaskets) without problems during many (>5 years). 

Companies like ceramtec:

http://shop.ceramtec.us

or kyocera:

www.kyocera.fr

could certainly help you.

Thanks @ Noel

Accuglass may also be able to help. They have made several feedthroughs for us.