Design of a new Compton-TDCR spectrometer at Sofia University for the characterization of Liquid Scintillation...

This work presents the development of a new Compton-TDCR spectrometer at Sofia University for studying the non-linearity of liquid scintillation cocktails. The TDCR counter is equipped with Hamamatsu R331-05 photomultiplier tubes (PMTs), and its performance was compared with the performance of three other TDCR counters operated at Sofia University. Efficiency variation technique is used to evaluate the kB parameter and to calculate the activity of ³H and ¹⁴C sources. The comparison between the counters demonstrates excellent performance of the newly developed system. The Compton channel of the new system uses a high resolution n-type germanium detector, which ensures high accuracy in the Compton electron energy. Results from Monte Carlo (MC) simulations investigating the source collimation and the spectrum in the gamma detector are presented. Birk's ionization quenching formula was fitted to the experimental data, and the obtained kB value shows good agreement with the kB determined by the efficiency variation technique.