Development of a Device to Measure the Electron Transverse Diffusion in Gas Media

In this work, a new device developed to measure the transverse diffusion of electrons in gases is described. In this device, electrons are generated in a semitransparent cesium iodide (CsI) photocathode, exposed to xenon VUV light from a pulsed Xe lamp. Electrons are allowed to drift a fixed distance, which can be varied between 3.5 and 60 mm, and the charge is collected in a multistrip anode electrode. In the present work, we report the results obtained in xenon and in methane under reduced electric fields of 0.92 and 1.53 Td, for drift distances between 3.5 and 11.5 mm. The electron characteristic energy associated with the transverse diffusion, as measured with this new device, is 5.75 ± 0.45 eV and 7.15 ± 0.63 eV at 0.92 and 1.53 Td, respectively, for xenon and 0.065 ± 0.005 eV and 0.097 ± 0.008 eV at 0.92 and 1.53 Td, respectively, for methane, which are in good agreement with results from the literature.