Re: PCBs in UHV

VWWall wrote:
Jim Thompson wrote:
On Thu, 30 Apr 2009 14:50:18 -0700, Jim Thompson
<To-Email-Use-The-Envelope-Icon@xxxxxxxxxxxxxxx> wrote:

On Thu, 30 Apr 2009 21:10:18 GMT, James Arthur
<bogusabdsqy@xxxxxxxxxxx> wrote:

whit3rd wrote:
On Apr 27, 8:19 pm, John Larkin
<jjlar...@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
Has anybody done PC boards to run in UHV (1e-9, maybe -10 torr)
without serious outgassing?

[...]

If it's a simple circuit, you might be
able to weld one up, or if it's more complex, consider welding a box
for it that has glass/metal, or ceramic feedthroughs, so that only
some external wiring comes out to the vacuum.
Whacky idea: seal the proto in a glass envelope, a "circuit in
a bottle"?

That wouldn't be terribly hard to do.


James Arthur
Not so wacky! If you have a university nearby with a vacuum and glass
shop. Maybe Kovar pins into a glass envelope?

Brings back memories. Haven't done any glass blowing/vacuum systems
since around 1960.

...Jim Thompson

Actually, you can probably buy the header as a unit (like a 7-pin-mini
tube), build your electronics onto the header, vacuum and seal.

...Jim Thompson
Just take an old noval, (nine pin), glass tube, cut the glass envelope, remove the tube elements, and you've got a nice nine wire header, The envelope is lead glass, easy to attach to any similar enclosure.

The "pins" are Kovar, and other metal leads would need to be spot welded to them. The final electronic envelope would not need to be evacuated, but could be filled with dry nitrogen, and then sealed off.

Maybe a half-vacuum, which would split the max stress in half, both
for UHV and atmospheric conditions?

There's something "steam punk" about sealing semiconductors in
glass and bringing the leads out to a 9-pin base!

Here's the French guy's video:
http://blog.makezine.com/archive/2008/01/make_your_own_vaccum_tube.html

Cheers,
James Arthur
.

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