Norris E. Bradbury

Preferential and Initial Ionic Recombination in Gases

In an attempt to determine the fraction of ions lost by recombination in an x‐ray ionization chamber, a theory has been developed for the processes involved in preferential and initial ionic and electronic recombination. The theory considers the change of the energy distribution of the electrons as they diffuse away from the parent atom. From this, together with a knowledge of the electron capture process, the space distribution of negative ions formed may be obtained. The probability of the initial electron recombining preferentially with the parent positive ion is considered as well as the preferential process for the negative ion. Knowing the initial spacing of the ions, it is possible to calculate the recombination occurring during the diffusion process until random distribution is reached. The final volume recombination may then be calculated in the usual manner. The theory may be employed in both electronegative and free electron gases and to ions formed in the presence or absence of an electric field.

The Los Alamos Laboratory

The following statement was made by the director of the Los Alamos Scientific Laboratory at the beginning of a press conference held on September 24.

The effect of electron attachment on the ion mobility curves in the Zeleny air blast method of ion mobility measurement

Abstract In a recent paper Professor John Zeleny published curves obtained for ion mobilities at different ion ages in relatively pure N2 using his classical air blast method. Two features are of especial interest; one the apparent gradual displacement of the negative ion peak to lower mobilities as the ion age increases and the other a marked asymmetry of the electron peak on the low mobility side. This Zeleny interprets as an unresolved negative ion mobility of value about 100 cm./sec. per volt/cm. Such a mobility can only be explained by a carrier that is ion part of its life and electron part of its life, the electronic and ionic phases alternating frequently. The writers indicate that the latter interpretation cannot be correct on the basis of the energies and probabilities involved in electron attachment. Analysis shows that the whole series of the observed phenomena in N2 by this method are successfully accounted for on the proper application of the simplified theory of electron attachment to the air blast method. Since the attachment phenomena have to date not been applied to this type of mobility study it was felt of importance to present this analysis in order to guide future investigations by this method.