Pulse-Shape Analysis and position resolution in highly segmented HPGe AGATA detectors

International audienceThe performance of the Pulse-Shape Analysis (PSA) in AGATA HPGe detectors was investigated and improved employing a $\gamma$ -ray source measurement based on $ e^{+}e^{-}$ annihilation radiation after decays of$^{22}$Na by $ \beta^{+}$ decay. The first interaction positions of the two 511keV $\gamma$ rays were determined and the connecting line of these two positions was compared to the known source position as a measure for the PSA performance. The position resolution and its dependence on the PSA parameters were investigated by varying most relevant input quantities: the charge carrier mobility of the holes, the response of the employed measuring electronics especially the preamplifier rise time. The relative statistical weight of charge signals and transient signals was scrutinized. The optimal distance metric of the grid-search algorithm and its impact on the position resolution were determined