Dissociative recombination at elevated temperatures. I. Experimental measurements in krypton afterglows

A description is given of a pressure driven shock tube and the techniques which have been developed to investigate the variation with gas temperature of the electron-molecular ion dissociative recombination coefficient alpha . Double probe detectors are used to measure, at times in the afterglow, electron densities of a plasma slice located between the shock front and contact surface of the nearly one-dimensional gas flow. The experimental parameters are discussed in relation to their influence on the recombination process. In krypton at 900 K, alpha is found to have the value 4.2*10 -6 cm 3 s -1 and at 2700 K it has followed a T -3/2 variation to the value 9.6*10 -7 cm 3 s -1 .