Patent ID: 7309992

Claim:
A method for the analysis of impurities in a main gas comprising: (a) an ionization of impurity atoms and molecules in their collisions with particles of definite energy in an ionization chamber; (b) measurement of an electric current between at least two electrodes at least one of which is an anode and one of which is a cathode positioned in said chamber, as a function of the voltage applied between said two electrodes; (c) selection of a main gas pressure and of said ionization chamber geometry in such that a distance between any point in said chamber and the nearest chamber wall or one of said electrodes is of the order or less than a mean displacement of an electron before it loses a given portion of its kinetic energy; (d) providing equipotential space at the region of said ionization chamber, where said ionizing collisions occur; (e) determination of amount of electrons with characteristic energies, which are generated in the ionization of said atoms or molecules, from electric current dependence on the voltage applied between said electrodes; and (f) identification of said impurities in said main gas from parameters of said electrons.