Talk:Ionizing radiation/Archive 2011

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Risks of Ionizing Radiation-confusion about external source or internal to the body

Confusion exists in the discussion in the article and on the talk page of the risks of ionizing radiation because of the failure to denote where the source of the radiation is located; outside the body or inside. While the human skin is permeable to radiation, it still offers considerable protection. Once inside the body, killer radiation can wipe out cells mercilessly.

There is a vast difference in risk because sources of ionizing that are ingested with food or breathed in through the lungs may have a more subtle risk that is all the more insidious. The ionizing radiation inside the body may destroy living cells. The unprocessed raw materials released can be very deadly to other nearby cells and a chain reaction can set in where many cells are destroyed -all from just one radioactive particle. This article fails to even hint at this feature of ionizing radiation

Speaking of citations-the UNSCEAR 2000 REPORT Vol. II report can do nothing better than to quote itself in an earlier Morph- UNSCEAR 1993- see point 20 in the 2000 report here. [1] —Preceding unsigned comment added by Ray Phenicie (talkcontribs) 23:21, 14 March 2010 (UTC) Ray Phenicie (talk) 23:28, 14 March 2010 (UTC) Ray Phenicie (talk) 23:37, 14 March 2010 (UTC)

Yes, ingestion of radioactive material is a completely different topic. Perhaps we could mention this, but it probably belongs in an article on poisons and toxic substances, rather than this article. Dbfirs 07:55, 16 April 2011 (UTC)

first paragraph

The first paragraph currently reads, in part, "The occurrence of ionization depends on the energy of the individual particles or waves, and not on their number. An intense flood of particles or waves will not cause ionization if these particles or waves do not carry enough energy to be ionizing." But this phenomonon shows this is simply not true [2]. I think it would make more sense to restrict the claim to reduced metals, where there is great documentation of this fact. For other materials, as this finding points out, we don't really know. 018 (talk) 15:25, 6 August 2010 (UTC)

Now says: In the absence of heating or multiple absorption of photons (a rare process), an intense flood of particles or particle-waves will not cause ionization if each particle or particle-wave does not carry enough individual energy to be ionizing (e.g., a high-powered radio beam). Simple enough. SBHarris 22:56, 16 April 2011 (UTC)

Munroe's chart

Randall Munroe, author of XKCD, has produced an excellent and very well sourced chart of ionizing radiation exposure levels. I think it's a bit too large to inject directly into this article, but perhaps parts of it could be converted to SVG and displayed, while the data it gathers could be incorporated? He's released the chart to the public domain (see the note at the bottom). -Miskaton (talk) 19:57, 21 March 2011 (UTC)

Inverse square law

I have moved the following fragment here for discussion because it seems to contradict the cited reference. I'm not an expert, so perhaps there is some factor of which I am unaware. If so, could someone explain it, otherwise I'll assume this was vandalism.

Fragment: practically i = Io e^(-ux)
Dbfirs 07:50, 16 April 2011 (UTC)
I agree it is excessive detail for the context and seems to be wrong anyway, as it does not describe an inverse-square relationship. –CWenger (^@) 08:03, 16 April 2011 (UTC)
I believe that equation belongs under topic #4 of the list where you found it, "Shielding". It describes the exponential attenuation of radiation passing through shielding matter. Looks like somewhere along the line it got moved into the wrong part of the list by some mathematically-challenged editor. --ChetvornoTALK 14:28, 16 April 2011 (UTC)
Ah, yes, that explains why it was there (in the wrong place). If it is worth putting back in the correct place, it needs an explanation of the variables, or re-phrasing in English, but I'm not convinced that it's worth the effort. Dbfirs 17:05, 16 April 2011 (UTC)
I agree, it doesn't really belong there anyway. Otherwise we'd need equations for every item. Also, I'm going to merge item #3 into item #4 in the list as most sources just say "time distance shielding". –CWenger (^@) 17:41, 16 April 2011 (UTC)
On a tangentially related topic, I would have thought that the halving distance would be independent of the energy of the particle since it just depends on atoms being in the way, but I suppose high-energy particles will generate other radiation, so I might be wrong there. What are high-energy alpha particles called if they are not called alpha particles? Dbfirs 19:06, 16 April 2011 (UTC)
I can't imagine this is true. It would take a lot more lead to attenuate neutrons traveling at near the speed of light compared to slow neutrons, right? Not sure what you mean by the second question. –CWenger (^@) 19:10, 16 April 2011 (UTC)
Yes, perhaps you are correct, in which case we need to alter our article slightly because skin or a few centimetres of air will be totally inadequate to attenuate high-energy particles. It suppose it depends on whether slow-speed alpha particles are more likely to interact with an atom that they graze past. If not, then half of them would still be stopped in the same distance wouldn't they? Or are they re-emitted from atoms that they strike at high speed? (On the second point, I can't remember where it was that I read that high energy particles are not called alpha particles, but it seems odd -- ignore my question.) Dbfirs 08:14, 17 April 2011 (UTC)
Nuclear interaction cross-sections virtually always increase as particle energy goes down, hence why I think the halving distance is not independent of the particle's energy (ignoring secondary reactions). I think the current statement in the article is fine, because (1) it says "substantially attenuate", which is vague and does not say block completely, and (2) it specifies "low-energy alpha and beta radiation", suggesting air or skin are not sufficient shielding for high-energy alpha and beta radiation. –CWenger (^@) 08:33, 17 April 2011 (UTC)
Yes, my mental model had constant cross-section, so was not a close match to reality. Thanks for correcting it. I'm happy with the current phrasing in the article. Dbfirs 22:43, 17 April 2011 (UTC)

Explantion at the Chemical level

An explanation about how the radiation actually ionisies atoms would be nice. EG: gamma rays ionise atoms because the gamma ray (being a photon) hits an electron making it jump a few shells away from the nucleus, however the gamma ray is so powerful it knocks the electron away from the nucleus altogether. thats the only one i know how it actually works, some more explantions would be nice, i cant find them anywhere else on wikipedia =|. —Preceding unsigned comment added by (talk) 13:07, 8 May 2011 (UTC)