A New Method of Positive Ray Analysis and Its Application to the Measurement of Ionization Potentials in Mercury Vapor

A new method of positive ray analysis is described which lends itself particularly well to the study of the nature of the ions formed by single electron impact in gases, the efficiency of their production, and the measurement of their ionization potentials. The novel feature of the method is the use of the uniform magnetic field of a large solenoid so to concentrate a beam of electrons as to provide a linear source of positive ions. The ions are then pulled across the magnetic field and subjected to an em analysis by a suitably designed analyser. Some preliminary results are given for mercury vapor in which the ionization potentials of Hg²⁺, Hg³⁺, and Hg⁴⁺ are found at 30, 71, and 143 volts respectively.