Information on Ionizing Radiation


We are consistently bombarded with radiation that is for the most part harmless to humans but can cause adverse effects if abnormally heavy or prolonged exposures transpire. The figure below shows many of the common and harmful types of radiation to which people are frequently exposed.


Image from: https://www.rsc.lt/eng/spin/pe/keliai.gif

What is ionizing radiation?

Ionizing radiation is radiation with enough energy so that during an interaction with matter, it can remove tightly bound electrons from within an atom, causing the atom to become charged or ionized. Ionizing radiation occurs in two forms : 1. Waves. 2. Particles. Only the high (UVB and above) frequency portion of the electromagnetic spectrum is ionizing. Several frequencies are dangerous to humans:

 Types:
  1. UVB
  2. Gamma rays
  3. Alpha rays
  4. Beta particles
  5. X-rays
*Cosmic Rays produce Gamma Rays and Alpha Rays.*
External radiation exposure as formulated by the U.S. Nuclear Regulatory Commission:

Explanation and Effects of Radiation:

* UVB-Although a person's epidermis is adapted to the sun's radiation, ultraviolet radiation still causes damage and mutation to cells within the body. These mutations are held in check by the P53 protein, any dysfunction of the P53 gene has been linked to tumor formation. UVB radiation comprises 290-320 nm region of the EM spectrum. With proper skin protection, such as modern sun blocks, this radiation is of modest concern.

* Gamma rays-Gamma rays are of a short wavelength and therefore are the most energetic of the types of radiation listed here. Gamma rays often accompany beta and alpha rays, and can penetrate most substances. This radiation is always produced from nuclear fission and is the cause for such extensive shielding of nuclear facilities. The shielding required would need to be as thick as a concrete wall, or as dense as lead and depleted uranium. X-rays fall into this category.

* Alpha rays-Alpha particles are positively charged particles ejected from radioactive nuclei, these are often shielded by the dead layers of the human skin. However, if radionuclides that emit alpha particles enter your body they can be very harmful.

* Beta rays-Beta particles are emitted from a nucleus during radioactive decay. Similar to alpha particles, beta particles also cause severe damage to your health if they enter your body, nevertheless external exposure to large amounts of beta radiation may cause skin burns. Because they penetrate much further than alpha particles, it would take considerably more shielding to block them. Substances such as wood, plastic, or thin metal are adequate as shielding.

Penetration depth:


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