Page "Alpha decay" Paragraph 20

However, another component of alpha radiation is the recoil of the parent nucleus, termed alpha recoil.

Due to the conservation of momentum requiring the parent nucleus to recoil, the effect acts much like the ' kick ' of a rifle butt when a bullet goes in the opposite direction.

This gives a significant amount of energy to the recoiling nucleus, which also causes ionization damage.

The total energy of the recoil nucleus is readily calculable, and is roughly the weight of the alpha ( 4 u ) divided by the weight of the parent ( typically about 200 u ) times the total energy of the alpha.

By some estimates, this might account for most of the internal radiation damage, as the recoil nuclei are typically heavy metals which preferentially collect on the chromosomes.

In some studies, this has resulted in a RBE approaching 1, 000 instead of the value used in governmental regulations.