Has the Lowest Ionizing Radiation?

Gamma rays may pass all the way through a human body without striking anything. They are considered to have the least ionizing power and the greatest penetration power.

What is the lowest ionization radiation?

Definition boundary for lower-energy photons

The lowest ionization energy of any element is 3.89 eV, for caesium. However, US Federal Communications Commission material defines ionizing radiation as that with a photon energy greater than 10 eV (equivalent to a far ultraviolet wavelength of 124 nanometers).

What gives off most ionizing radiation?

The largest natural source of radiation exposure to humans is radon gas. While radon gas has always been in the environment, awareness of its contribution to human radiation exposure has increased in recent years. Radon's primary pathway is through air space in soil and rock.