Ionizing vs. non-ionizing radiation, units, and safety (updated) Answered

Not too stupid, but too uneducated. Where in high school do you get any of the background necessary to understand radiation issues, or especially the different biological effects of alphas vs. betas, etc.?

Where in high school do you get any of the background necessary to understand radiation issues

one of my elective classes in the 9th grade was Nuclear Energy (although most of the class was made up of seniors).

I don't know if they still carry that class or not.

I remember that kind of class in my 6th grade, enough to know about the kinds of radiation and their types of effects.

The class I attended would have been a bit much for the 6th grade (except for the greatly advanced) as they used 2nd year college texts for the class. We did learn an awful lot about what is harmful and when, concerning radioactive isotopes and the reason Alpha, beta, and gamma radiation pose different threats when either inside or outside the body. I loved that class .... why I didn't pursue that line of study, I'll never know...

Well, you should be around the folks I have to deal with.... =P

The hydrogen doesn't shield, it moderates. As you say, the neutrons "bounce off", and thereby slow down. The carbon has a high absorption cross-section ¹²C(n,¹³C) (if I got the notation right).

In the reactor, this bouncing is what causes a higher reactivity at the outer part of the core. In fact, the water jacket around surrounding the reactor room at prototype sites IS the shield for the surrounding area.

Ah, good point. Same as with the borated polyethylene we used for a while to "shield" our PMTs. It's not an absorber-type shield, but rather a thick scattering.

I know that's what people are wondering. Because I work at a National Laboratory, I am necessarily hesitant to make apparently definitive statements which contradict current policy. What I can do is provide quantitative information, and pointers to reliable documentation, and expect my readers to exercise their own intelligence and use of calculators to come to conclusions.

...And I see that I haven't completely closed the loop on that. What I should add to my topic above is the conversion from Bq and Ci to Gy and Si or rem for some common isotopes (¹⁴C, ²⁴¹Am, ⁶⁰Co), and also give some guidance on how to compare those numbers to existing radiation we're all exposed to normally. Give me some time to get that done...

The best safety rule for any radioactive source, even the tiny amount (37 kBq is about 10 nCi) in a smoke detector, is to follow 1/r²: keep some distance away from it, and wear reasonable and practical protective equipment (latex gloves, dust mask) otherwise. If you touch it (get it on your skin) or ingest it (breathing dust, getting under a hangnail, whatever) then it will do more damage (1/0 = infinity :-).

I love the Banana reference, can a modern scantilator pick them out from other sources going across the north - south Korean boarder ? And I understand your cautious wording, there is so many variables that could make it safe to use and many more that would make it very dangerous, but with that said, would Am241 illuminate a older scantilator (( just wondering I have no plans on taking apart my smoke detectors, they are optical ones / rate of temperature rise anyhow, yep always hated how the ionization ones go off when you make toast ))

Well, scintillators are fine for detecting beta and gamma radiation (electromagnetic interactions), but their energy resolution tends to be kind of crappy. I'm not sure if the industrial models would be good enough to separate the 1.5 MeV⁴⁰K -> ⁴⁰Ar decay from other nearby lines.

A nuclear engineer would know this stuff much better than I do.

It depends on the scintillation crystal and the multiplier. We use a Sodium Iodide crystal and a cascading multiplier, which is OK, but there are better alternatives.

I have an ionization smoke detector, it once went off when I blew out a candle near it.

Something interesting about the ionization ones and the optical ones...

If you are in short supply of fuel and need to light something then a wick lighter will set them off if you fill it with normal petrol, spray tyre buffer (flammable and the old stuff could literally slough off skin, the new stuff is flammable and useless) and most other larger hydrocarbon based flammables, presumably incomplete combustion = more soot and smoke

Aftershave will set them off as well as deo in ionization versions but burning it won't unless there's powder in it.

An interesting one and a point to make, smoke coming directly from the end of a cigarette will set them off if it's held close enough for much smoke to get in, it tends to float up very fast and go around objects, however smoke being exhaled or even just puffed from the filter end but not having been through your lungs will not set it off, strangely cigar smoke seems to just not set them off, presumably the leaves burn cleaner but cigarettes have material added plus KNO³ which makes them burn faster...

One weird thing is that buildup has a habit of not setting the ionization ones off until it gets to extreme levels, however if you're dusting around them the dust can set them off, small insects and spiders can set either off if they get inside...

Most smoke detectors, as sold, should have it fairly well shielded, right? It is only if one tampers with the shielding that one can, um, get burnt.

Yes, indeed. But consider the community here. "Tampering" with closed-up consumer products is part of the culture. People will open things they probably shouldn't, so providing safety guidance isn't unreasonable.

Oh I understand that. And mistakes of my youth still hang around me also in the form of some scars that could have been worse then scars.

I was just adding my 2 cents so no one thought that having a smoke alarm would pose a danger. :-)

_{^{I can't get past the first sentence}}

It's helpful to look up the terms he is using.

well on the Ionizing vs. non-ionizing radiation, units, and safety scale

you guys are up here
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^{and I am down here}

Did the introductory stuff help, or just make it more confusing for you? It's not easy to find the right balance between "details for the non-experts" and "talking down to people." I really do want this stuff to be useful and interesting.

I don't know about anyone else, but I really appreciate the level of detail you supply on this kind of thing. I found the introduction helpful. Sometimes a lot of it of it is over my head, but I like having all the information, because I can look up the things I don't understand, and I get frustrated with explanations that don't go as deep and leave a zillion questions unanswered.

I appreciate the thought but its not really a subject that I could get into immediately I will probably pick it up when I do something similar in school

...Just looked at your profile. Yes, I see your point. If you have a decent science teacher at your school (or even better, physics and chemistry teachers) I would encourage you to take this to them, and go over it with them. I know how intimidating teachers can be (it is a "power relationship," after all), but my universal experience is that the good ones really love to teach, and to be part of the process of discovery. Try seeing if they'd be available during lunch, or after classes. At the very least, get some age appropriate books at the library, so you can spread out information in front of you and compare things. Don't give up! The challenge of figuring something out is a great way to expand your mind.

"...Just looked at your profile. Yes, I see your point. " does my profile not please the great kelseymh. Must improve profile to please gods...

ROFLOL!

I'm sorry. That was not my point at all. In your profile, you listed your age as 14. I had (incorrectly) assumed that you, and others reading what I had written, were approximately college age. I made assumptions about what training you had which were incorrect. That is not in any way meant to be an insult or an offense. You had explained in your previous comment that there were things I wrote which you hadn't yet encountered in school. That's not a situation I had considered, but when I read your profile I realized my mistake.

Agreed. I'm going to go ask my old AP Bio teacher about the AM 241 (he also teaches Chem)

Thank you again for your comments! I've tried to add some better explanatory material, and have rearranged the text slightly. If there are specific things you don't understand, please consider yourself welcome to post your questions, ask for clarification or details, or (especially!) point out things you think are incorrect or inaccurate.

that's only if you must :-p

Thank you for the comment; I'll add some introductory information

It is also (as Adrian noted) useful to look up terms you don't understand. Wikipedia is an excellent starting point; just paste the word into their little search box.