The anti-proton annihilation at Darmstadt (PANDA) experiment is designed for studies of the strong force. It will be built and placed in the high energy storage ring (HESR) at the facility for antiproton and ion research (FAIR) in Darmstadt. The beam of the HESR consists of anti-protons in an energy range from 0.8 GeV to 14 GeV and will collide with a fixed hydrogen target. The detectors of PANDA are designed for e.g. detailed hadron spectroscopy by detecting the anti-proton-proton interactions in the transition region between perturbative and non-perturbative quantum chromo dynamics (QCD).

This thesis summarizes preparatory experiments with a PANDA forward endcap electromagnetic calorimeter (EMC) prototype performed at MAX IV laboratory, for studying the response to photon energies below 100 MeV using vacuum photo tetrodes (VPTTs) as photo sensors. The prototype was cooled down to -25 °C. Two different sets of VPTTs were investigated as well as two different analog to digital converters (ADCs), peak-sensing ADCs and sampling ADCs. The results show that with VPTT photo sensors, in combination with sampling ADCs, the technical design report (TDR) requirement, with regard to energy resolution, can be fulfilled even at low energies.