Improvements in the modelling of micro fission chambers operated in current mode

Abstract

We recall the theoretical bases necessary to model micro 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 resolutions of the charge transport equations. Using these results, we calculate the voltage extension of the saturation plateau, as function of parameters such as the electrode geometries or the characteristics of the filling gas.

Recent developments on micrometric fission chambers for high neutron fluxes

“…The basic ideas are first to reduce the creation of electron-ion pairs and then to reduce the time of charge collection due to the proximity of the electrodes. In [8] this option was already explored by reducing the cathode diameter to 1.5 mm.…”

“…This has clearly improved the quality of the signal, especially during the first hours of irradiation. In [8] it is proposed to use heavier noble gas to reduce the impact of impurities. This solution has to be tested.…”