How can I differentiate between alpha particles and helium in an enclosed space?

[connorp]

Can someone recommend (if possible) a way to detect the amount of helium in a given enclosed space? I'm designing an experiment in which I will need to measure the amount in an otherwise vacuum.

 

[russ_watters]

If helium is the only thing in the container, why not just measure the pressure?

 

[nsaspook]

How to detect the amount depends on the quality of the vacuum and the level of helium in that volume.

Normal Helium mass spectrometer/RGA leak detection methods will work and can be fairly accurate if you have a calibrated measurement device or a calibrated leak to use as a standard.

Find a copy of 'A User's Guide to Vacuum Technology by John F. O'Hanlon" for measurement details.

http://www.lesker.com/newweb/Techni...etect_01_Overview.cfm?section=leaks&init=skip

 

[Wellesley]

Can someone recommend (if possible) a way to detect the amount of helium in a given enclosed space? I'm designing an experiment in which I will need to measure the amount in an otherwise vacuum.

Gas Chromatograph or Mass Spectrometer (RGA)

 

[connorp]

If helium is the only thing in the container, why not just measure the pressure?

Oops. Forgot to mention that the experiment would involve the alpha decay of a radioactive source, hence, I need a way to differentiate between alpha particles and helium.

 

[nsaspook]

Oops. Forgot to mention that the experiment would involve the alpha decay of a radioactive source, hence, I need a way to differentiate between alpha particles and helium.

That's out of my level of expertise but to detect helium with a mass spectrometer/RGA you need to ionize it first so it can be accelerated into the mass detector. For charged particles like alphas a silicon detector could be used.

http://www.ortec-online.com/Solutions/RadiationDetectors/silicon-charged-particle-detectors.aspx