Comunicazione
A didactic experiment to measure the angular correlation between the two gamma rays emitted by a $^60Co$ source.
Nicassio N., Pirlo R., Amato E.C., Anelli A., Barbieri M., Cataldi D., Cellamare V., Cerasole D., Conserva F., De Gaetano S., Depalo D., Digennaro A., Fiorente E., Gargano F., Gatti D., Loizzo P., Loparco F., Mele O., Perfetto G., Pillera R., Schygulla E., Troiano D.
A didactic experiment carried out by a group of Physics masters' students at Bari University is presented. The purpose was the study of the angular correlation between the two gamma rays of 1.17 MeV and 1.33 MeV emitted in typical $^60Co$ decays by means of two NaI(Tl) scintillators equipped with photomultiplier tubes read out by a digital oscilloscope. Several runs were performed with the Co source at different angles between the two scintillators. Additional runs were performed removing the source, to study the backgrounds from cosmic rays and from gamma rays emitted by the radioactive isotopes $^208Tl$ and $^40K.$ Our results showed that the signal rate changes with the angular separation in agreement with the theoretical expectations by Hamilton dating back to 1940 and with recent measurements documented in literature. Students learned to plan and set up an experiment, to take data and to perform basic analysis. Care was taken to understand the limits of our experimental apparatus and possible improvements.