Improvements in the Modeling of Sub-Miniature Fission Chambers Operated in Current Mode

We review the theoretical basis necessary to model sub-miniature fission chambers operated in current mode. For these detectors, we propose formulae for the lower and upper limits of the saturation zone, obtained through analytical and numerical solutions of the charge transport equations. Using these results, we calculate the voltage width of the saturation plateau, as a function of parameters such as the electrode geometries or the characteristics of the filling gas.