It would have to be extremely low pressure seals. Helium is so light it is incredibly difficult to store. When running some of our tests, I watched helium literally flow through the metal of a non-stainless steel connection on top of the LHe Dewar.
We ran some tests on pressure transducers at -450 f. Used a Cryostat to vacuum pull Liquid helium out of the Dewar and into our Cryostat. It was amazing figuring out that the pure Gaseous Nitrogen we used in our pressure lines was liquifying and then freezing SOLID when we pulled a vacuum on our pressure lines. We ended up having to use Helium as our pressurized gas in the pressure lines so that we could obtain accurate pressure readings.
> It would have to be extremely low pressure seals. Helium is so light it is incredibly difficult to store. When running some of our tests, I watched helium literally flow through the metal of a non-stainless steel connection on top of the LHe Dewar.
ok, hmmm, it sounds as if i got my story wrong then (not the first time lol). if i bump into my source i will post it (but i may have mangled what it in fact stated). thanks for the cool helium info!
Hydrogen even more so!