Detecting Gamma-Gamma Coincidences from the 60Co Decay

Some radioactive isotopes produce two correlated gammas as a result of different decay processes. Although the gamma detection efficiency of Geiger counters is not high, coincidence experiments between two counters at close distances from a low activity source may provide evidence for such correlation. An example is given with a 60Co source and two small Geiger counters, employing an Arduino board to read the signals from the detectors and search for coincident signals.