Symbols for Particles and radiation P proton 1H nucleus n neutron particle of zero charge and a=1 d deuteron 2H nucleus T triton nucleus -a alpha particle He nucleus electron Electron from atomic orbitals β negatron Negative electron emitted by the nucleus β+ positron Positive electron emitted by the nucleus y Gamma ray Electromagnetic energy(photon) emitted by the nucleus X ray xray Electromagnetic energy emitted as a result of electron transitions in the atomic orbitals Neutrino(中微子) Emitted inβ- decay processes(2 types) 北才浮 2005-9-13 NECPKU, C L, Liu