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 11B and 19F 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.
@article{arxiv.nucl-ex/0311002,
title = {A multi-detector array for high energy nuclear e+e- pair spectrosocopy},
author = {K. E. Stiebing and F. W. N. de Boer and O. Froehlich and H. Bokemeyer and K. A. Mueller and K. Bethge and J. van Klinken},
journal= {arXiv preprint arXiv:nucl-ex/0311002},
year = {2008}
}