Performance of the prototype of the PANDA-EMC

The electromagnetic calorimeter (EMC) in the target region of the future PANDA detector at FAIR is one of the crucial components of the spectrometer to study antiproton annihilations in order to investigate yet undiscovered charm-meson states and glueballs. The calorimeter is composed of cooled PbWO₄ crystals arranged in a barrel and two end cap sections. The present paper describes the construction and performance of a fully functioning prototype PROTO60 representing a small section of the barrel. The performance, when operated at a temperature of T=-25°C was determined exploiting cosmic muons and energy marked photons from the MAMI-C accelerator (Mainz, Germany) up to photon energies of 1.4 GeV. The response was measured with sampling as well as charge-integrating ADCs for a comparative study. Energy, position and time resolutions are discussed in detail and compared to expectations based on previous tests and simulations. The obtained results fulfil already the required limit set by the envisaged physics program of PANDA in spite of several options for further improvement, such as the light collection with an additional large area APD.