Spatial Imaging of Charge Transport in Germanium at Low Temperature
The purpose of this experiment is to observe the oblique propagation of electrons through germanium by exciting a point source of charge carriers with a focused laser pulse on one face of a germanium crystal. After the electrons are drifted through the crystal by a uniform electric field, the pattern of charge density arriving on the opposite face is mapped and used to reconstruct the trajectories of the electrons. These measurements will verify in detail the Monte Carlo analysis utilized in the Cryogenic Dark Matter Search to model the transport of charge carriers in high-purity germanium detectors, including both oblique electron propagation and inter-valley scattering.
Moffatt, R. A., Cabrera, B., Kadribasic, F., Redl, P., Shank, B., Young, B. A., Brandt, D., Brink, P., Cherry, M., & Tomada, A. (2014). Spatial Imaging of Charge Transport in Germanium at Low Temperature. Journal of Low Temperature Physics, 176(5), 943–951. https://doi.org/10.1007/s10909-013-1013-4