Considering radiation weighting factors only, how many times more dangerous are alpha particles than protons?

1 Answer
Jul 9, 2016


Ten times.


Radiation weighting factors (#w_r#) are used to caluclate the equivalent dose from the absorbed radiation dose. It takes into account how much biological damage each type of radiation can cause.

These factors have changed over the years and the newest #w_r# come from the ICRP 2007 (International Commission on Radiological Protection). They are not yet implemented in all countries, but are considered leading in the radiation protection field.

The weighting factors are:

  • photons: 1
  • electrons, myons: 1
  • protons and charged pions: 2 (was 5)
  • alpha particles, fission fragments, heavy ions: 20
  • neutrons: continuous function of neutron energy (were categories)

So #w_r# for protons is 2 and #w_r# for alpha particles is 20. In these terms, alpha particles cause ten times more damage then protons.