  A multi-detector array has been constructed for the simultaneous measurement
of energy- and angular correlation of electron-positron pairs produced in
internal pair conversion (IPC) of nuclear transitions up to 18 MeV. The
response functions of the individual detectors have been measured with
mono-energetic beams of electrons. Experimental results obtained with 1.6 MeV
protons on targets containing $^{11}$B and $^{19}$F show clear IPC over a wide
angular range. A comparison with GEANT simulations demonstrates that angular
correlations of $e^+e^-$ pairs of transitions in the energy range between 6 and
18 MeV can be determined with sufficient resolution and efficiency to search
for deviations from IPC due to the creation and subsequent decay into $e^+e^-$
of a hypothetical short-lived neutral boson.
