Electron mobility and longitudinal diffusion coefficient in high-density gaseous xenon

Measurements of the mobility and longitudinal diffusion coefficient of electrons under external electric fields were performed in high-density gaseous xenon at room temperature. The xenon density and reduced electric field ranges were from 2:55 × 10 ²⁰ to 1:73 × 10 ²¹ cm ^-3 and from 0.027 to 0.19 Td, respectively. The electron transport parameters of the density-normalized mobility, density-normalized longitudinal diffusion coefficient, and the ratio of the longitudinal diffusion coefficient to the mobility were found to increase with increasing density for reduced electric fields at around 0.04 Td. This result indicates the density-dependent variation of the effective momentum-transfer cross section for electron-atom scattering. It was also found that the density-dependent variations are different depending on the electron transport parameters, which can be attributed to the difference in parameter sensitivity to the momentum-transfer cross section.