所谓衰变是指原子核自发地放出某种粒子而转变为新核的变化 .放射性元素衰变时 ,通常会同时放出α、β和γ三种射线 ,但在某些特殊情况下 ,某些放射性元素可能只放出α射线或只放出β射线 .α衰变或β衰变时产生的新核若处于激发态 ,便会辐射出γ光子 ,即任何情况下都不会只放 The so-called decay is the change that the atomic nucleus spontaneously emits a certain kind of particle and changes into a new nucleus. When the radioactive element decays, it usually emits three kinds of ray of alpha, beta and gamma at the same time, but in some special cases, some radioactive elements may Only emits alpha rays or emits only beta rays. If a new nuclei generated during alpha decay or beta decay is in the excited state, it will radiate gamma photons, ie not only