  We present the results of using standard IMARAD CZT detectors with a 100 MHz
readout of the anode and cathode pulses. The detectors, 2 cm x 2 cm large and
0.5 cm thick, have 64 Indium pixellated anode contacts at a pitch of 2.5 mm. We
investigate the possibilities to improve on the detector's photo-peak
efficiency and energy resolution using two depth of interaction (DOI)
indicators: (i) the total charge induced on the cathode and (ii) the drift time
of the electron cloud determined from the anode and/or the cathode pulses. The
DOI correction with the cathode charge gives better results, increasing the 662
keV photo-peak efficiency by 57% and improving the energy resolution from 2.33%
to 2.15% (FWHM, including the electronic noise). The information on the time
dependence of the induced charge can be used as a diagnostic tool to understand
the performance of the detector. Detailed comparison of the pulse shapes with
detector simulations gives the electron mobility and drift time and makes it
possible to assess the weighting potential and electric field inside the
detector
