Swimming In A Deadly Sea: Awash In Radiation
(Page: 2 of 6)
Kathleen Deoul: Well, what is the difference?
Copulos: To begin with, there are three types of ionizing radiation that are associated with nuclear energy: Alpha, Beta and Gamma radiation.
Kathleen Deoul: OK. What's the difference between them?
Copulos: Well, Kathleen, first there are Alpha rays. Alpha radiation is comprised of a charged particle and is relatively weak. In fact it cannot penetrate the outer layer of the skin, and can be stopped by a piece of paper. But the fact that Alpha radiation is the weakest form doesn't mean that it's harmless. If material that emits Alpha radiation is ingested - taken inside your body - it can pose a significant health risk.
For example, in the 1920s, women who were making luminous watch dials using a paint that contained radium contracted cancer in large numbers. It was discovered that many had the habit of putting the paint brushes in their mouths to bring them to a fine point. What they didn't realize was that when they did this they also swallowed small amounts of the radium-laced paint. Over time, the continual exposure to Alpha rays from the paint they swallowed was what caused their cancers. So, even Alpha rays are not harmless.
Kathleen Deoul: But what about the other types of ionizing radiation?
Copulos: Well next come Beta rays. Beta rays are made up of positively or negatively charged electrons. They are much stronger than Alpha rays. Still, Beta rays can be stopped by a layer of clothing or a relatively thin layer of a metal such as aluminum. If the skin is directly exposed to them, however, unlike Alpha radiation, Beta rays can cause tissue damage.
Kathleen Deoul: But when people think about protection against radiation, they don't generally think of paper or clothing, they think about huge concrete barriers or thick lead containers, so that must be related to Gamma rays.
Copulos: You're absolutely right Kathleen. Gamma rays are the most powerful form of ionizing radiation. Gamma radiation is made of what are called photons. Photons are weightless packets of energy that also comprise the visible light spectrum. They also form the link between atomic particles. In the case of Gamma rays, these photons are very intense. This is what makes Gamma rays so dangerous. Fortunately, while there are natural sources of Gamma radiation, it is most often associated with man-made products so we don't normally encounter them in circumstances that lack the proper protection. This is fortunate because Gamma rays can easily pass through tissue and cause severe damage to the human body. They can also be absorbed by tissue, thereby causing damage to the entire body. It takes several feet of concrete or several inches of lead to stop a Gamma ray.
Swimming In A Deadly Sea:
Awash In Radiation
Part 1 | Part 2 |
Part 3 | Part
Kathleen Deoul, Media Matters