Hermetically sealed BNC

cally sealed.

rr. I recall these ones we used in grad school. They had an O-ring groove where the base screwed into the panel.

I'd rather have a solder post on the other side.) And these by RF precissio n

=BNC

o-ring groove.

dp/1207553

adiall.

Hi George. This takes me back to my time a Cambridge Instruments, where ele ctron microscopes called for loads of coxial feed-throughs into vacuum.

The connections into the specimen chamber were mostly O-ring sealed BNC's. I think we got ours from Greenpar and Amphenol - everybody seemed to make t hem, though Farnell didn't usually stock them.

For the detection photomultiplier, we needed a higher voltage coaxial conne ctor, which I think we got from Radiall. I had a particular problem with th e electron-beam tester, where I used a fast focussed photomulitplier tube t hat needed up to 1.65kV, where the regular photomultipliers were selected ( by the manufacturer) to get by with 1kV or less

For the electron gun we needed much higher voltages and rather lower leak r ates.

Radial did do very high voltage coaxial connectors, but IIRR they weren't v acuum rated.

I think we ended up having parts made by a local glass-to-metal seal specia list, where the glass got precision ground after it had been sealed to the metal, and indium wire was used to create the compression seal. They'd make us up a batch from time to time - not cheap, but cheaper than t he Radiall equivalents. I mostly wasn't directly involved, so it's mostly i mperfectly remembered hearsay.

Hi, George:-

How about these?

I see them as cheap as $13, with plenty of stock.

Best regards, Spehro Pefhany

If you really need a low leak rate, try MDC Vacuum Products for the BNC.

Steve

There is also Ceramaseal:

Steve

tically sealed.

Torr. I recall these ones we used in grad school. They had an O-ring groo ve where the base screwed into the panel.

(I'd rather have a solder post on the other side.) And these by RF preciss ion

t/dp/1207553

Radiall.

lectron microscopes called for loads of coxial feed-throughs into vacuum.

. I think we got ours from Greenpar and Amphenol - everybody seemed to make them, though Farnell didn't usually stock them.

Hi Bill, I think I paged through the Amphenol catalog today and didn't see anything. I never heard of Greenpar. But I'll give both a look.

nector, which I think we got from Radiall. I had a particular problem with the electron-beam tester, where I used a fast focussed photomulitplier tube that needed up to 1.65kV, where the regular photomultipliers were selected (by the manufacturer) to get by with 1kV or less

rates.

vacuum rated.

ialist, where the glass got precision ground after it had been sealed to th e metal, and indium wire was used to create the compression seal.

the Radiall equivalents. I mostly wasn't directly involved, so it's mostly imperfectly remembered hearsay.

I wonder if I could just drive a threaded BNC into a tapered threaded hole, with some teflon tape. (Hmm or epoxy bnc's into a pipe thread adapter dohicky.)

Thanks for the remembrances,

George H.

Beauty! Thanks. Mark me down for a beer (or beverage of choice) If you're ever in Strykerville we can go to the flip side for Abbots Deluxe wings. George H.

Hi Steve, thanks.. (those all look spendy) I didn't know the UHV people would stand for an o-ring seal. :^)

George H.

I like the look of those,too. I wonder how the Be/Cu contacts are joined to the Kovar terminal.

Resistance weld, maybe?