Electron transport theory in gases: must it be so difficult?

This article reviews recent progress in both experimental and kinetic theoretical determination of charged particle transport coefficients in electric and magnetic fields in the context of wire gas chamber detectors. The “Magboltz” code of Biagi [13] is discussed. It is pointed out that there is really no alternative to the accurate “multiterm theory” of Ness [3–5] if high precision is required, but this may not be readily accessible to the nonspecialist because of its mathematical complexity. On the other hand, “momentum transfer” theory provides relatively simple expressions for transport coefficients and has an accuracy of the order of 10%. We focus on this simplified theory in the bulk of the paper, discussing some previous results and giving new formulas. In order to illustrate the utility of the method, we have performed numerical calculations in several cases of relevance to wire gas chambers.