Response of AGATA segmented HPGe detectors to gamma-rays up to 15.1 MeV

In many in-beam gamma spectroscopy experiments the detection of high-energy gamma rays in the range up to 10-20 MeV is of primary importance. New generation high-resolution gamma-ray spectrometers like AGATA and GRETA are composed of position sensitive segmented HPGe detectors and provide a reconstruction of the gamma-ray tracks. The performance of AGATA detectors in this energy range has, however, never been studied in detail. A measurement of the response to 15.1 MeV gamma rays has been performed using two HPGe triple clusters of the AGATA Demonstrator array, operating at LNL-INFN. This manuscript presents the preliminary results of a test of the AGATA detectors for the measurement of high-energy gamma rays, in terms of detection efficiency, energy resolution, tracking and performance of the pulse shape analysis (PSA) algorithms.