Spectroscopic response of a CdZnTe multiple electrode detector

The spectroscopic performances of a CdZnTe detector (crystal size: 5×5×0.9 mm3) with five electrodes (cathode, anode and three steering electrodes) were studied. The anode layout, which consists of a circular electrode (φ=80 μm) surrounded by two ring electrodes (gap=100 μm; radial width Δr=100 μm) and by one electrode that extends to the edge of the crystal, is mostly sensitive to the electron carriers, overcoming the well known effect of the hole trapping in the measured spectra. We report on the spectroscopic response of the detector at different bias voltages of the electrodes and at various photon energies (109Cd, 241Am and 57Co sources). The CdZnTe detector exhibits excellent energy resolution (0.87 keV FWHM at 22.1 keV, 1.15 keV FWHM at 59.5 keV and 1.91 keV FWHM at 122.1 keV; working temperature −10 °C) and low tailing (FW.1M to FWHM ratio of 1.87 at 22.1 keV, 1.93 at 59.5 keV and 2.01 at 122.1 keV). This study stresses on the excellent spectroscopic properties and the stability of the CdZnTe detectors equipped with a custom anode layout. Furthermore, the obtained results make such detectors very attractive candidates as X-ray spectrometers mainly for medical applications.