Abstract
We investigated various diagnostic techniques to measure the 511 keV annihilation radiations. These include step-wedge filters, transmission crystal spectroscopy, single-hit CCD detectors, and streaked scintillating detection. While none of the diagnostics recorded conclusive results, the step-wedge filter that is sensitive to the energy range between 100 keV and 700 keV shows a signal around 500 keV that is clearly departing from a pure Bremsstrahlung spectrum and that we ascribe to annihilation radiation.