CPB Ljubljana 2018 course book

Radioactive Decay

He 4 2

▪ Alpha decay

This occurs in very heavy nuclei, with very high atomic number, Z > 82. All nuclides with atomic number higher than 82 are unstable and the majority follow the alpha decay scheme. This is shown in the following equation:

AZ

A 2Z

 

4

4 2

parent



daughter

 Q He  

Q α is the disintegration energy which is distributed between the kinetic energy of the emitted α-particle (this represents the majority) and the recoil energy of the daughter nucleus. This means that the emitted α-particles have discrete energy values (hence a discrete energy spectrum) that are lower than the disintegration energy Q α .

226 88

222 86

4 2

Ra



Rn

8706 .4   He

MeV