Beta particles electrons

Becquerel determined that beta particles were actually electrons through his studies of uranium radiation. This finding linked electrons not just to electric currents but also to atomic structure, particularly in radioactive atoms.
 Antoine-Henri Becquerel France 1900 Beta particles electrons

Becquerel determined that beta particles were actually electrons through his studies of uranium radiation. This finding linked electrons not just to electric currents but also to atomic structure, particularly in radioactive atoms.