CdTe spectroscopy analyzer with built-in pulse shape discrimination system

The analyzer with planar CdTe detector and pulse shape discrimination system, intended for use in monitoring and identification systems of radioactive materials at NPPs, waste fuel reprocessing plants etc., has been developed. The analyzer allows receiving high energy resolution (⩽3.5 keV at 662 keV line) in a wide range of energies registered from 40 to 1500 keV. The application of the effective small-sized thermoelectric cooler and special cooled input stage of the preamplifier, placed in gas-filled chamber of a special design, ensures serviceability of the analyzer in a wide range of operating temperatures (-10÷+60°C) at a temperature instability no more than 0.002%/°C. The main section of the preamplifier is made of an ultralow noise operation amplifier AMP AD 797 with the purpose to secure wide dynamic range of output voltages and improve stability in a range of operating temperatures. For high performance of the analyzer, a new method of pulse discrimination is applied. It is based on restoring the detector signal up to the rectangular shape. The system has a high sensitivity to insignificant modifications of the detector pulse shape. It allows to carry out fine adjustment Thus the number of pulses at the maximum of the complete absorption peak decreases not more than 20% (for 662 keV)