Portable spectrometer based on segmented HPGe detector with background suppression

The results of development of a portable spectrometer based on a segmented HPGe detector with background suppression for radioactive waste monitoring are presented. The detector front and coaxial segments had the diameter of 68 mm and the lengths of 20 and 50 mm correspondingly. The energy resolution of the planar segment was 1.3 keV at 122 keV and for the coaxial detector -2.5 keV at energy 1.33 MeV. The relative efficiency on the whole crystal was 60% at an energy of 1.33 MeV. The background suppression system had three independent channels of amplification and shaping of spectrometric pulses for planar and coaxial detector outputs with a nonswitchable shaping time constant of 2 μs and for a total detector output with a switchable shaping time constant of 2 μs or 4 μs. The background suppression system is PC controlled by the special software. Testing of the spectrometer with isotopes Cs-137 and Cs-137+Co-57 shows that a relative improvement of the peak/Compton ratio for registration with and without suppression for an energy 662 keV is 1.4 and for an energy 136 keV is more than 1.5.