A new experimental system for electron transverse diffusion measurements

Abstract

The knowledge of the electron transverse diffusion in detection media is mandatory to assess the accuracy in systems that require precise event tracking. A new experimental system was developed to measure the transverse diffusion of electrons in gases. Electrons are generated in a transmissive CsI photocathode by Xe VUV light from a pulsed Xe lamp, and drift a fixed distance that can be varied from 4 to 60 mm. The charge is then multiplied in a GEM and collected in a multistrip target. The results were obtained for Xe and CH4 at two different E/N values, at 800 Torr, for drift distances between 4 and 12 mm. The characteristic energy associated with the transverse diffusion obtained were (5.75±0.45) eV and (7.15±0.63) eV for Xe, and (0.065±0.005) eV and (0.097±0.008) eV for CH4, respectively for 0.92 and 1.53 Td. All values are in good agreement with results from the literature.