Tag Archives: radiation testing

Radon: The Radioactivity Decay Pathway

Below is a detailed chart showing the radioactivity pathway to radon from the original U-238 atom. Also shown are the different types of radiation:

Alpha Radiation – (from Radon-222 as an example) high energy helium nuclei (almost no penetrating power, but does a great deal of damage at close range to cells and DNA – will not penetrate outer layer of skin, but can cause direct harm to epithelial cells in the lungs if inhaled) It causes approximately 5 X the damage of gamma Radiation or X-Rays.

Beta Radiation –  high energy electron (much lighter than an alpha particle but it has a greater penetration)

Gamma Radiation – high energy photon (essentially without mass but has a high penetration factor through shielding)

Penetration and of Alpha, Beta and Gamma Radiation

Penetration and of Alpha, Beta and Gamma Radiation

If you follow the diagram below, the radioactive decay of Radon-222 to Lead-210 results in the emission of 3 alpha particles, 2 beta particles and a discrete amount of gamma radiation. (the nature of which is an electromagnetic wave, not a particle) Because radon decay products (RDPs) are electrically charged particles, they readily adhere to suspended dust particles (which can be inhaled) or other surfaces in a phenomena known as “plate-out”. Either pure RDPs or the particles they are attached to can be inhaled.


Radon gas decay pathway

Radon Gas Decay Chart