I have recently been reading about radiation exposure, from Marie Curie’s isolation and study of radium in the 1890’s to the horrible fate of the “Radium Girls”, Eben Byers, and the guy who developed the radium paint used for watch and instrument dials in the early part of the 20th Century, to the atomic bomb era, Cold War, various accidents… Not that it was all about death and destruction. Smoke detectors have saved many lives with little risk to the users and most depend on Americium, there’s all sorts of medical imaging, judicious use of radiation in medicine, in detecting weaknesses in aircraft parts before failure and death…
Anyhow - there’s all sorts of varieties of radiation. I just want to be sure I have a handle on some of it.
Mostly, I’m talking here about ionizing radiation, not things like light.
There are alpha-emitters, which, well, emit alpha particles. Alpha radiation is basically a bare helium nucleus. It can cause damage to living tissue but is easily blocked by minimal barriers, like the dead skin cells that form the surface of your skin. The biggest problem is if alpha-emitters get into your body where your living cells have no barrier between them and the bouncing alpha particle. Given their (relatively) high mass they can be extremely dangerous once in the body because their high mass means they can do a lot of damage compared to other radioactive particles. Then they can cause all sorts of havoc. To deal with alpha-emitters in your environment you don’t eat the local food, don’t drink the water, and don’t breathe the air. Yes, you wear a serious hazmat suit. A thorough shower of said suit followed by careful removal should be all the protection you need.
Beta-particles are basically rampaging electrons OR positrons (hey! anti-matter! How cool! How Star Trek!) They are more penetrating than alphas, less so than gammas. A thin metal plate can stop them, but they will get through your skin. This is where a “lead suit” type of hazmat gear could be useful even if pretty damn heavy. So… fantastic! We can protect again alpha and beta! (Albeit with come inconvenience and trouble). Betas are harder to shield from, but if they get inside the body may not be as damaging as alphas do to having almost no mass.
Something I only recently learned about betas is that when you shield against them and they go through the shielding material they slow down, and can emit gamma rays during the slow down. Also, the atomic weight of the material used as a shield also effects the energy level of those gamma rays. So it’s actually safer to use a shield of, say, aluminum or wood than of lead because the gamma that results from beta slow down would be less from the lighter shields than the lead. So maybe you don’t want a lead hazmat suit, you really do want a hat made of tinfoil (aluminum) in that situation!
Gamma rays are photons. Really, really energetic photons. They are also really, really penetrating. They have uses in industry as, essentially, x-rays on steroids for imaging purposes because they go through a lot of stuff. Shielding against these guys is challenging although, fortunately for squishy creatures like us, the Earth’s atmosphere does a pretty good job of filtering out a lot of gamma rays that would otherwise come to us from outer space.
What I’m still fuzzy on here, though, is the role that neutrons play in radiation. I know that shooting neutrons at atoms can cause changes in atomic number, which can cause all of the above sorts of radiation. The shooting neutrons come from atoms fissioning, right? Also from fusion? From matter/anti-matter interactions going >BOOM<?
In most cases, radiation doesn’t cause a person or items to become radioactive, that’s usually a case of people or things becoming contaminated with radioactive isotopes (hence, don’t eat the food, don’t drink the water, don’t breathe the air, and take a shower). Under what circumstances does radiation cause the formation of radioactive isotopes in people and things? Gamma rays? Wandering neutrons? Is there something else I’m missing here?