ISBN:  Unavailable

Category: Unavailable

Page count: 238

A collinear electron-ion beam technique has been developed for measuring absolute cross sections of electron-ion reactions at low interaction energies. As an example of this technique, absolute recombination cross sections have been measured for diatomic molecular nitrogen ions and electrons over an energy range of 0.1 to 5 eV. It is found that the recombination coefficient is essentially independent of the interaction energy from 0.1 to 0.6 eV. The results are consistent with the assumption that dissociative recombination is the dominant recombination process. The experimental technique consists of merging a fast mass and energy analyzed ion beam with a collinear electron beam in a well defined collision volume and detecting the emergent energetic neutral particles resulting from the recombination reaction by kinetic ejection of secondary electrons at a tungsten dynode of a magnetic electron multiplier. Synchronous digital data averaging was used for signal-to-noise ratio enhancement, and high speed digital computer data processing was used for data reduction to obtain the recombination coefficient and the recombination cross section as a function of the interaction energy. (Author).