The performances of the composite Cluster detectors of the EUROBALL array have been investigated with \gamma -rays of 15.1 MeV produced in the reaction ¹¹B + D \to ¹²C + \gamma + n at 19.1 MeV. The Cluster detector is made of 7 encapsulated germanium crystals mounted in a single cryostat. The pulse height to energy conversion of the individual crystals is found to be very linear. The coincidence fold distribution is given for various energies and compared to simulation calculations of the Cluster response. A simple add-back procedure improves consistently the full energy peak efficiency. The efficiency of the composite detector is compared to that of large volume BaF₂ scintillator.

PACS numbers: 29.30.Kv, 29.70.--e