Electronic components suitable for high vacuum in SEM chamber—volatile vs non-volatile?

No Crusty is not going into outer space, but one of my ex co-workers asked me to make a small module to work inside the chamber of a scanning electron microscope. (Hi vacuum).Now I used to run an electron microscope and the last thing you want is a contaminated chamber.

Before I start down this design path, what components can I use that work and keep working in a vacuum? Which one gas volatile and non volatile ?Which ones explode.Happy Christmas Experts

Hi Crusty-I don't have any experience with electron microscopes, but NASA has published some data about selection of materials for spacecraft including outgassing info.  Look here:  NASA Outgassing infoHope this helps!
-Rick

Hi
Perhaps NASA could answer, they are pretty much experts in that field
I would suppose components that have mil-spec would be a good start as their planes and missiles operate at extremes. How much of a vacuum do you need? I understand it is pretty hard to create a perfect one.
A colleague has capability to drop pressure (safely) from ~1Bar (atmospheric pressure) to between 100 and 200mBar, so if you want a particular component "tested" for any obvious destruction it could be fun to throw it in the chamber and watch
I suppose electrolytic capacitors could start to leak as the pressure reduces if their body isn't designed to withstand the internal pressure now acting on it.  Similarly if any "air bubbles" are present in a component then they too could cause self destruction.
Analogue Devices produce space qualified components and an interesting article is herehttp://www.analog.com/media/en/technical-documentation/technical-articles/Challenges-for-Electronic-Circuits-in-Space-Applications.pdfPerhaps they or similar could advise? It would be too easy if Farnell (or similar) had a filter for space qualified...
Regards

Thanks Rick,
Its about what I thought very few capacitors. I thought the space boys would have more info on this especially the satellite  guys.-Crusty

 Hi ChipFryerI gather that my friends SEM chamber is running at (7 x 10 exp(-5) Torr) with vane and diffusion pump systems running. Not sure as to how this equates to outer space, but I expect that a lot of electronic components will fail in this environment. Having in the past needed to clean the specimens chambers of SEM it's not something I want to get my friend doing because I used the wrong components.Many thanks for your contribution though.

Hi7E-5 Torr...? Wow that is low. That's about 9E-8 Bar if my calculator is correct.ST are another manufacturer of space qualified components.
http://www.st.com/en/aerospace-and-defense-products/space-products.htmlWhilst you have no need for RHA certification I'm sure they could advise on components suitable in the chamber you describe.Regards

PSFrom what I gather space is approx 10E-11 to 10E-17 Torr so anything certified as space qualified should have no problem in the chamber you describe.

Hi ChipFryer
Thanks for your input.

Use hermetically-sealed components. These will be expensive and may be hard-to-find, but they are available, as they are used in aircraft, missiles, and satellites. Use hermetically-sealed tantalum capacitors instead of aluminum electrolytic capacitors (you may have to remove the plastic wrapper on the outside of the metal hermetic case, if the plastic outgasses). TO-5 or ceramic integrated-circuit packages are suitable. Check on the outgassing of your PCB. You could consider having custom hermetically-sealed hybrid circuits built. You will have to figure out how to conduct the heat away from your circuitry.

Hi Peter,Many thanks for the input I had thought that the hermetically sealed components would have to be the route taken. Thanks also for the consideration about heat conduction away from the circuit, I had not considered this very obvious physical property of a vacuum.