Gamma spectrometer based on CeBr 3 scintillator with compton suppression for identification of trace activities in water

The performance of a spectrometry system (SPEC) for identification of trace activities in water is presented. The SPEC detector is a part of the TAWARA_RTM platform designed for monitoring of water processed for distribution by the Waterworks Company. The SPEC system is dedicated for identification of radioisotopes emitting γ-rays of energies between 50 keV and 2 MeV. The SPEC detector comprises a CeBr 3 scintillator grown from specially purified raw material with reduced content of actinides that produce unwanted alpha particle background. In order to reduce the Compton scattering background, an active anti-Compton shield (ACS) made of BGO is used. In addition, a passive lead shield around the ACS is used for further suppression of the external background. The SPEC detector is designed for use with a dedicated concentrator system, that will be used for absorption of a selected group of radioactive elements that may be present in water processed at the waterworks. The system is tested upon capability to detect the γ-ray emitters with activity according to the guidance levels published by the EU in the Council Directive.