日本語
Hi There!
I'm currently working on a new connection-panel for a samplestick of a cryostat; therefore I need to bring about 24-30 signals (coax) from a "vacuum" (~0.1-10mbar or 1ATM of He) to the outside world. 
As I would like to keep grounds seperate between the signals (-> star-ground next to the sample, down in the cryostat) the Connectors' ground should be isolated from its mount, however i've not seen vacuum-sealed isolated connectors. The other option is to use standard connectors (i.e. SMA) and have a isolating panel, but This option is not the greatest in terms of shielding.
So I had the following idea: Why not just use a PCB as interface panel, solder in PCB-mount connectors and connect the cabling on the inside. (here also a two-layer PCB with a groundplane on one side would serve as rather nice rf-shield)
Now my question:
Is a standard FR-4 PCB air/He-tight? (at room temperature)
Any comments or questions are appreciated 
- Comments(1)
A****min
Jan 15.2020, 10:05:31
Glass seal and DBC substrate.
The other side is, if you have any through holes or through-board components, will they leak? And, if not, but you have SMT parts, then will they be too strained and crack under the flex due to withstanding air pressure?
Don't be surprised if vacuum sealing is hard. As far as I know, all that stuff is expensive, and probably with moderately good reason, too.
