Collection Time of Electron-Hole Pairs in a Coaxial Ge(Li) Radiation Detector

Current and electric charge pulse shapes obtained for the collection of only one electron-hole pair released by an ionizing event in the sensitive volume of a coaxial Ge(Li) detector cooled at liquid nitrogen temperature, were calculated. By considering the pairs generated in the close vioinity of the detector electrodes, as well as those created in an intermediate region, maximum and minimum durations of the current pulses have been found. Low electric field intensity is assumed (charge carrier velocity directly proportional to the electric field intensity).