The DAMA/R&D set-up is general purpose low background set-up used to test PMTs and detectors prototypes and to realize small scale experiments. DAMA/R&D has been upgraded several times and optimized for every measurement to allow the maximum reachable experimental sensitivity.
DAMA/R&D has been used also in measurements investigating ββ decay modes
in various isotopes by means of low background scintillators and of samples; both
the active and the passive source techniques have been exploited as well as the
coincidence technique.
A particular attention is dedicated to the isotopes allowing the investigation of the resonant 2EC or of the ECβ+ decay channels. In fact, in the first case an enhancement of the rate by some orders of magnitude is predicted for the case of coincidence between the released energy and the energy of an excited state. The investigation of neutrinoless β+β+ (2EC and ECβ+) processes can refine the understanding of the contribution of right-handed currents to neutrinoless 2β− decay; therefore developments of experimental technique to search for β+β+ decays are strongly required in order to improve methodologies for future increased sensitivity. These setups have allowed us to obtain competitive results in these studies.