The PARIS cluster coupled to the BaFPro electronic module: data analysis from the NRF experiment at the γELBE facility

The first cluster of the constructed PARIS calorimeter was assembled and tested at the γELBE facility at HZDR, Dresden, Germany. The experiment was aimed at the evaluation of the performance of each detector separately as well as the whole PARIS cluster with discrete γ-ray energies seen by the PARIS ranging up to 8.9 MeV. As the detectors use phoswich configuration, with 2' × 2' × 2' LaBr₃(Ce) crystal coupled to 2' × 2' × 6' NaI(Tl) one, great care must be taken during the data analysis process to obtain the best possible values for energy resolution. Two algorithms for data transformation from matrices created with slow vs fast pulse shaping to energy spectra were tested from which one was chosen for further analysis. An algorithm for adding back energies of γ-rays scattered inside the cluster was prepared, as well. Energy resolution for γ-rays in 2-8 MeV range was estimated and is presented in this paper. (paper)