The proton decay of radioactive nuclei

Abstract

Experiments on radioactive nuclei proton decay are described. The data on two proton emitters detected from the exposure of Ni to Ne 20 and O 16 beams are given. The first emitter (Ne or Mg light isotopes) has a half life of 85±15 msec and emits protons of 5±0.2 MeV energy, while the second emitter has a 23±4 sec half life and emits protons of 2.5±0.2 MeV energy. After a series of experiments we concluded that the second emitter is one of the Br or Kr light isotopes, i.e., in this case subbarrier proton emission takes place (the Coulomb barrier height is about 8.5 MeV). It is most probable that protons are emitted from a daughter nucleus after positon transition; the half life under measurement is associated with this transition. The process of proton emission with E p = 5 MeV is similar to that for delayed neutron emission. The mechanism of subbarrier proton emission with E p = 2.5 MeV is analogous to that for long-range alpha emission by heavy nuclei. The possibility of configuration isomer proton decay is also considered and is not excluded in the case of a 2.5 MeV proton emitter.