β-delayed Multi-particle Emission From ³¹Ar

The β⁺ decay of ³¹Ar was investigated in an experiment at the GSI-FRS spectrometer.The ions of interest have been produced in the fragmentation of a ³⁶Ar beam at 880 MeV/nucleon and implanted in a time projection chamber with optical readout. In addition to β -delayed one and two proton emission, for the first time the emission of -delayed 3 protons has been observed. The branching ratio for this decay mode is found to be (0.07 ± 0.02)%.