CdZnTe drift detector with correction for hole trapping

The results are presented of a CdZnTe drift detector for which the energy determination can be corrected for hole trapping. The electronic noise and the hole contribution to the signal are reduced and the signals are also corrected for any residual effects of hole trapping. This is achieved by using drift strips and an anode strip on one side of the detector crystal in combination with a single planar electrode on the other side. Below 100 keV, the resolution (in FWHM) was electronic noise limited. Using a planar electrode, the peak of 241Am at 59.6 keV has a width of 14.1 keV. The resolution improved to 3.21 keV when using the anode strip. This is comparable to the electronic noise of 3.11 keV. At 661 keV, no peak could be observed in the spectrum of 137Cs with the planar electrode. However, with the anode strip, a peak with a width of 17.9 keV was observed. The resolution improved further to 6.9 keV after correction for hole trapping. After correction, the peak-to-valley ratio was 40 : 1, with a peak-to-Compton ratio of 4 : 1.