Novel solutions in isotopic mass-spectrometric analysis of hydrogen-helium mixtures. How to get reliable data

The paper is aimed on the choice of the optimal instrumentation for isotopic analysis of hydrogen-helium mixtures. A critical review is made of former and commercially available instruments as well as of goal approaches to such an instrument. The so called 'compromised' approach is chosen as the most attracting one; the instrument should resolve all multiplets at 2-7 a.m.u. excluding T+-3He+, but it should not be oriented on resolving of isotopically derived hydrocarbons: the necessary resolving power, about 27 000, practically excluded possibility of accurate measurement is a wide component concentration range. F number of technical ideas are put forward aimed on an optimal specialized instrument for the problem under discussion. It should be compact to low ion scattering on residual gas and have a resolving power of 3500 at relative peak height of 10-3. It was shown that only static magnet instruments can give the line quality good enough for such measurements. A combination of called electron ionization and prism double focusing mass analyzer is probably optimal; a prototype of such an instruments was developed in tested in the USSR period.