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160 mSv: chronic dose to lungs over one year smoking 1.5 packs of cigarettes per day, mostly due to inhalation of Polonium-210 and Lead-210
is too large by three orders of magnitude. A more realistic value would be in the range of µSv instead of mSv. Do the math... or use a search engine of Your choice:
This article is surprisngly unhelpful. After events such asChernobyl, Three Mile Island and more recently Fukushima the media have quoted units of radiation measurement in milisieverts and microsieverts. What readers want to know is what is the difference? And what is the scale of risk (eg compared to a chest x-ray, exposure from a transatlantic flight, living in Dartmoor England or in poarts of India where background radiation is far higher than the norm). Can someone please make this article accessible? —Preceding unsigned comment added by 22.214.171.124 (talk) 21:13, 4 April 2011 (UTC)
I think better accessibility is happening and the article now covers the formal definition and examples of effects of dose in sieverts. I have made and added a graphic which may help to clarify the relationship between the dose types, which can be very confusing for the new reader switching between articles. Dougsim (talk) 23:00, 9 December 2013 (UTC)
This is incorrect, but I don't know how to correct it. The gray (Gy) is correctly defined; and the sievert is defined from the gray by multiplying by a radiation weighting factor. The radiation weighting factor is defined as 1 for gamma radiation. Thus for gammas, 1 Sv = 1 Gy = 100 rad, which is approximately 87 roentgen (depending on the material.) If someone wants more info and can correct the entry, please email me at email@example.com .
I have removed the list of alleged effects of different levels of sieverts, as they are not appropriate in this article. The unit "Sievert" can be applied to either equivalent dose or effective dose. Such effects as "nausea" and "death" are not appropriate if quoted in terms of the effective dose, since effective dose refers to stochastic effects only. These figures may be true in terms of equivalent dose, but you would have to say which part of the body has been irradiated.
--Sievert 11:41, 2 Apr 2004 (UTC)
Equvalent dose vs. dose equivalent
The article at Equivalent dose states "The equivalent dose should not be mistaken for dose equivalent." Yet the Sievert article uses these terms interchangably in the same sentence. Someone who really understands the specifics should do some careful editing. Jedwards05 05:12, 17 July 2006 (UTC)
I have added a graphic showing the dose quantities with their correct names, and also given an explanation of how the nomenclature is used. Hopefully this will remove confusion. There is a coherent system, and careful use of terminology is important. Dougsim (talk) 07:11, 27 April 2014 (UTC)
In the following, 50% or more lethality is alleged for more than 3 and more than 4 Sv. Which is it?
More than 3 Sv will lead to death in less than two months in more than 80% of cases, and much over 4 Sv is more likely than not to cause death.
"Radiation produced by the granite of the United States Capitol building : 0.85 mSv/year"
If sievert is a measure of dosage received, it cannot also be a measure of radiation produced.
The same comment applies to several of the entries in the examples list. It seems that the original author has not adequately separated in his thinking the concepts of effective dose (measured in Sv) and activity (measured in Bq). Either that or he or she is not sufficiently rigorous in the forms of expression used. For example, the granite question, and also the defective items in the examples list could be corrected by a change in the wording; e.g. "Effective dose received by a worker in the United States Capitol building due to the radioactivity of the granite in the building: 0.85 mSv/year", assuming that this is actually what is intended. The entire article is very carelessly written, and seriously needs revision by someone who is in the habit of thinking clearly about what they intend to write. 126.96.36.199 (talk) —Preceding undated comment added 11:10, 2 February 2014 (UTC)
I've seen different tables of quality factors, and whatever values are used should be referenced. The best source I've found (not even an SI source!) is at ; a more authoritative version would be great. Note that this version has much more detail, disagrees on the QF for neutrons, and doesn't suggest a method for in-between values (that I noticed).
How do you work the quality factor(s?) into the equation? Can someone please give me an example how the Q values and N values work in an example equation, or maybe just put that into the article. I'm not particularly good at math, but I want to understand how it works, and I don't see any variables in the current example equation for Q or N. - Commandur (talk) 05:34, 8 December 2009 (UTC)
N values for other species
How come the relative N values are ranged from high value to low value, e.g. 0.3 – 0.03? It just looks odd. Wouldn't 0.03–0.3 make more sense, or is that just a regional bias? /188.8.131.52 11:22, 6 November 2007 (UTC)
Q controversy for alpha particles
I'm intrigued by the following statement: "There is some controversy that the Q or RBE for alpha radiation is underestimated due to mistaken assumptions in the original work in the 1950s that developed those values." Have you got a reference for that? —Preceding unsigned comment added by 184.108.40.206 (talk) 02:54, 28 January 2009 (UTC)
How does this scheme handle differences between people? Does a postmenopausal woman still have an N of 0.20 applied to her gonads? Does a non-smoker still have the higher 0.12 value for the lungs? If a nuclear power company knows that a woman has had a hysterectomy and has no gonads, can they assign her to work longer because she doesn't take that dosage? (what if you're comparing two postmenopausal women...?) etc. Wnt (talk) 22:55, 4 February 2009 (UTC)
Acute full body equivalent dose
Presumably the time period over which the dose is absorbed contributes somehow? Does 'acute' mean 'delivered over a short (to be qualified) time period'. 'acute'='sharp' suggests this. If so, article should say so, as this is a medical term or art. —Preceding unsigned comment added by 220.127.116.11 (talk) 14:18, 16 May 2009 (UTC)
I have added a clarification about the time period. The definition of "short" is somewhat vage because it is related to the response time of the repair mechanisms in the body, which is not well known; it is larger than seconds and shorter than weeks. 18.104.22.168 (talk) 14:32, 5 November 2009 (UTC)
This article needs serious work. It should be brought in line with the latest ICRP recommendations. Note that American literature on quality factors etc is not relevant (especially regulatory literature), as the US has not adopted the sievert. —Preceding unsigned comment added by 22.214.171.124 (talk) 15:04, 25 August 2009 (UTC)
Is it a time rate or cumulative ?
I am looking at this article trying to determine if sieverts are an instanteneous or cumulative amounts.
If the radiation source is emitting x sieverts and you are exposed to it for y hours, did you get a dose of xy sievert-hours ?
Or is the source emitting at x sieverts/hour and you are exposed for y hours, you get xy sieverts ?
It seems impossible that the rate of emission is measured in sieverts and the cumulative dose also in sieverts, thats what is being quoted and makes no sense. Eregli bob (talk) 08:10, 15 March 2011 (UTC)
From the article, it is clear that the unit sievert refers to (absorbed) dose , multiplied by a biological factor, not to dose rate (intensity). —Preceding unsigned comment added by 126.96.36.199 (talk) 09:56, 15 March 2011 (UTC)
From the examples I see, that a sievert is a commulative dose, because physiological effects depend on it e. g. 10 Sv cause death. An X-Ray gives you a certain dose, so a certain number of X-Rays would kill you.
The strength of radiation at a certain point in time is measured is Sv/time (e.g. Sv/hr or Sv/year). Spending a certain amount of time under this condition would collect an amount that could kill you. 8 mSv/hr would kill you in 1250 hours and would cause serious illness after around 125 hours.
Some of the examples are confusing and look wrong. (e.g.: Average dose to people living within 16 km of Three Mile Island accident: 0.08 mSv). Wouldn't that depend on how much time you have spent there.
- Re the TMI example, it says that it's an average. For any particular individual, the dose would depend on specifics for that individual (how much time spent at what distances from what particular radiation sources, and other factors). I take that example as reading that, on average, persons living with 16 km of TMI received .08 mSv, with no more than 1 mSv having been received by any single individual. Wtmitchell (talk) (earlier Boracay Bill) 03:30, 18 March 2011 (UTC)
I have found very quite different values: Chest radiography is 0.1 mSv Natural background radiation is between 1 and 3 mSv/year
- I found a US government source that said a single film from a chest x-ray is 0.1 mSv. Perhaps a typical exam includes more than one film? I found another source that said an x-ray was 0.5 mSv, as well as others that quoted 0.4 mSv. Unfortunately, I've closed those windows and don't want to go check again. There may not be a "right" answer, though, and a range may be better than a single number. I'll let others argue this out. 188.8.131.52 (talk) 12:40, 15 March 2011 (UTC)
Should benchmark sections be split to their own page?
The sections on dose and symptom benchmarks are long and not essential to a page about sieverts, but are still useful. I suggest leaving a few benchmarks on this page to help people understand the relative scale of a sievert, while linking to a separate article for additional benchmarks. That page could simply be called "Radiation levels." That page could list all the benchmarks, perhaps with an explanation of different measures as well, such as sieverts, rems and grays. 184.108.40.206 (talk) 12:53, 15 March 2011 (UTC)
- I agree with this in principle, but I'd prefer to leave it off for another week while Fukushima cools down. The sievert page is linked to from the Fukushima articles and I hope that easy linkage helps people get a grasp on what those all those numbers mean. --220.127.116.11 (talk) 04:51, 17 March 2011 (UTC)
- That sounds reasonable to me (the one who proposed the split, as well as the person who created the sections to begin with). Another reason for the split would be to allow one central source of figures for all radiation unit pages (rems, curies, etc.) to point to. But since TEPCO is reporting Fukushima readings in mSv, the Sievert page is understandably the focus of attention right now. 18.104.22.168 (talk) 16:07, 17 March 2011 (UTC)
- I also agree with a split of this page, moving part of it to the new page "Radiation levels". Sae1962 (talk) 18:49, 18 March 2011 (UTC)
- I didn't know that page existed. The chart is similar to what I've been envisioning for a "Radiation levels" page. But I don't understand the page title. This just looks like a list of radiation levels, with no formalized orders of magnitude established. 22.214.171.124 (talk) 17:21, 17 March 2011 (UTC)
- I don't think that article fills the need here (and the similar need being discussed in Talk:Banana equivalent dose#Units -- please see that discussion). There are qualitative divisions as well as quantitative divisions. I think there is a need for an article which distinguishes between units of radioactivity, units of radiation exposure, units of absorbed dose, and units of equivalent dose, which explains the relationships between them, which explains a bit about traditional units of radiation and radiation exposure vs. SI units of same, and which wikilinks to articles on each of the units of those four classes of units each of the articles on the individual units probably ought to avoid mentioning units not immediately related.).
- I'm not thrilled with Radiation levels as a name for the article. I see that an article on Ionizing radiation units exists. Perhaps that might serve, either as-is or with some changes. Wtmitchell (talk) (earlier Boracay Bill) 04:23, 19 March 2011 (UTC)
- Yes, seems to me all the benefits sought by creating such a new article would better be served by improving existing articles and the links among them, and perhaps by redestributing some of their material. Jim.henderson (talk) 11:03, 7 May 2011 (UTC)
- So, the proposal seems to have arisen due to a paucity of links to, thus unawareness of, several existing and relevant articles. This lack has been at least somewhat supplied since then, perhaps completely, and if nobody has said anything in favor for two months, does that mean there's no need for a split? Jim.henderson (talk) 08:19, 22 May 2011 (UTC)
examples in dpm
As a scientist used to thinking about dpm, I would like to see some examples of Sv to dpm conversions, I understand that there are a lot of adjustment factors; but I think this would give a nice, concreteness to the idea of the Sv I also dont think the article should be split - it reads very nicely as it is; splitting would really reduce it to a stub - please leave it alone !! —Preceding unsigned comment added by 126.96.36.199 (talk) 14:11, 15 March 2011 (UTC)
- But shouldn't articles on other units of radiation (rems, curies, rads, grays, etc.) also have a list of benchmarks, too? Why should all the benchmarks be focused on the sieverts page, or be duplicated and simultaneously updated across multiple pages? 188.8.131.52 (talk) 14:16, 15 March 2011 (UTC)
Hourly examples may confuse
To reduce the risk of confusion, I think all examples should list the numbers in the same unit. Now it says
- Highest reported radiation beside reactor 3 at Fukushima I: 400 mSv/hr
- Typical dose near Chernobyl reactor 4 and its fragments, shortly after explosion: ≈ 10–300 Sv/hr
This could fool someone reading this quickly into thinking these are equivalent numbers. Better:
- Highest reported radiation beside reactor 3 at Fukushima I: 400 mSv/hr
- Typical dose near Chernobyl reactor 4 and its fragments, shortly after explosion: ≈ 10,000-300,000 mSv/hr
In my opinion, we should list here more hourly dose examples, since a lot of people use Wikipedia as a reference and come here to see how the recently published hourly doses at Fukushima and Tokyo relate to other accidents and to the normal background radiation. For this purpose, it would be better to use similar prefixes that are used in the news and in the reports of (for example) IAEA and JAIF. These reports (with rare exceptions) use microsieverts for values up to four digits and use millisieverts for higher quantities. It even makes sense to make lower hourly doses comparable to background radiation (microsieverts), and to make higher hourly doses to be comparable to yearly doses / yearly limits (millisieverts).
Giving hourly doses for background radiation is useful (even if redundant wrt. yearly doses) since most of us needs a pocket calculator for division by 8760. The (almost) four orders of magnitude difference between hourly and yearly doses justifies using different SI prefixes.
Metric prefixes is a must have
- In my humble opinion, this part of the article calls for an appropriate use of unit prefixes in general. Because 400 mSv/hr is actually 0.4 Sv/hr, while 10,000-300,000 mSv/hr is 0.3 kSv/hr. In the world of science (including even secondary school physics) metric prefixes have been used to denote orders of magnitude for decades (if not centuries). For decades!
- The fact of existence of intellectually impaired individuals, incapable of grasping the concept of metric SI unit prefixes (which acts as a source of a great "confusion" to them), should not interfere with one's ability and resolution to use SI prefixes when it is appropriate in order to avoid use of absurdly long numbers (eg. 300000000000 nSv vs. 0.3 kSv or 0.00000000003 kSv vs. 30 nSv).
- Unless, of course, mSv is a generally accepted pseudo-standard unit, as, for example, the Megawatt is when dealing with power plants.
- Opinion of a professional required.
- Nameless Undead (talk) 09:15, 18 March 2011 (UTC)
- You're right but mSv is a generally accepted "pseudo-standard" unit. I presume this is because the annual dose limit is 1mSv for the public, so it is convenient to refer to doses in terms of this. It's is also often easier to when talking about a number of different values to retain the same order of magnitude. I think we should stick with convention and use mSv only. (examples of use of mSv e.g. , ).--Pontificalibus (talk) 09:24, 18 March 2011 (UTC)
- I usually prefer the prefixes instead of having do deal with big or small numbers and then have to count the zeros. Things measured in Sv are large dangerous doses, things in mSv are the numbers that matter for health decisions and things in μSv are neglectable for health. Even for Power plants, people use GW if the value is in the right range. People use tons, pounds and ounces for the appropriate things, only that in SI I don't need to think about how to convert them. I am more distracted by the use of mSv/year and mSv/hour, because they are magnitudes different and I don't have an intuitive way to convert them. Sconden (talk) 23:26, 23 March 2011 (UTC)
- Highlighting misspellings really detracts from the discussion. Please refrain from participating the next time you're tempted to do that.
- I doubt that anyone would argue that your examples like 300,000,000,000 nSv would reflect poor choices. Fortunately nobody proposed them, nor proposed using a single prefix everywhere. The proposal was that we try to use one prefix among figures which are likely to be juxtaposed.184.108.40.206 (talk) 21:38, 11 May 2011 (UTC)
- You're right but mSv is a generally accepted "pseudo-standard" unit. I presume this is because the annual dose limit is 1mSv for the public, so it is convenient to refer to doses in terms of this. It's is also often easier to when talking about a number of different values to retain the same order of magnitude. I think we should stick with convention and use mSv only. (examples of use of mSv e.g. , ).--Pontificalibus (talk) 09:24, 18 March 2011 (UTC)
I agree. The unit mSv/h such as a unit that has two prefixes. It is not allowed in SI. Either Sv, or s instead of h (second and hour) but not both of them. +
Fukushima example and censorship
The quoted source USA Today does not support the statement the Japanese Government uses censorship. Radiation measurements from the surrounding areas are in fact available (see these english translations). I am also not sure if such information is helpful in an article about a measurement unit. --220.127.116.11 (talk) 01:34, 18 March 2011 (UTC)
- Agree, this article is about Sieverts, we don't have to mention Fukushima at all. If we do we certainly shouldn't qualify it with any statements that add uncertainty. Such statements belong in 2011 Fukushima I nuclear accidents. --Pontificalibus (talk)
What does the "Single dose example"
- Average dose to people living within 16 km of Three Mile Island accident: 0.08 mSv; maximum dose: 1 mSv
mean? Is it a lifetime dose - or should it be moved to the "Yearly dose examples", say? I've checked the reference (and Three Miles island accident). I think it may be an accumulated value for a person living in the region through the accident, which should include absorption the rest of that person's life if there are still elevated radiation levels. But I am not sure - can this be cleared up?--Nø (talk) 10:52, 18 March 2011 (UTC)
- I don't read this as an assertion about the accumulated dose for any particular person. Rather, I read it as an estimate of the average dose accumulated as a result of the event by persons living within 16 km of Three Mile Island accident (roughly the total dose accumulated by all such individual persons divided by the number of such individual persons, but probably having been estimated based on some sampling and some statistical computations rather than by straightforward measurements and simple calculation of an arithmetic average). Some such persons will have accumulated more than the average and some will have accumulated less, depending on their particular individual circumstances. The supporting source cited presents it as follows: "The average radiation dose to people living within 10 miles of the plant was eight millirem, and no more than 100 millirem to any single individual. Eight millirem is about equal to a chest X-ray, and 100 millirem is about a third of the average background level of radiation received by U.S. residents in a year." Wtmitchell (talk) (earlier Boracay Bill) 23:24, 18 March 2011 (UTC)
Replaced Fukushima example from 8K to 1K, according to linked sources.
Need new page to explain Relationships between gray, Seivert, Bequerel, curies, roentgens, rems, and every other term used anywhere in Wikipedia for radiation.
...and I'd be delighted if the banana was used to show the relationship between these all.
Various news organizations quote "radioactivity" in their favourite expert's terms. And most of the wikipedia pages for these units seem to be devoted to explaining whether the unit is SI, or deprecated. This page thankfully explains Gys and rems, but bequerels are still a mystery. —Preceding unsigned comment added by 18.104.22.168 (talk) 08:51, 19 March 2011 (UTC)
- I agree. The switch at Japanese HNK World TV from reporting microsieverts and millesieverts to reporting becquerels is confusing to folks who are trying to follow radioactivity in the news. We need a way to convert from one system to another or to make rough equivalents with respect to radioactivity levels presented in different scales. A wikipedia article seems ideal to provide this information -- and a real service to the public. 22.214.171.124 (talk) 07:44, 27 March 2011 (UTC)
- It's not different units expressing measurement of the same thing in different ways, it is different units expressing different things. I found Table 1 in section 5 of this source useful, as well as the WP articles on Curie/Becquerel, Rad (unit)/Gray (unit), Roentgen equivalent man, Ionizing radiation#Units and Absorbed dose articles helpful. Wtmitchell (talk) (earlier Boracay Bill) 09:23, 27 March 2011 (UTC)
Radiation Dose Chart
A graphical chart showing the scale of different radiation exposures would help in giving a better and more immediate overview of the subject.
Randall Munroe has made such a chart, elaborating on a more basic chart by a Reed Research Reactor employee. As his work xkcd is released under Creative Commons, it is likely he won't mind us copying the idea of the chart.
I suggest that someone with the appropriate skillz make a similar chart to conform with the sources (avoiding the wiki self-reference, of course). Or, someone could contact Randall and have him upload the chart to Wikimedia Commons so others can improve it. TGCP (talk) 23:43, 19 March 2011 (UTC)
- From the blog post above:
Edit: For people who asked about Japanese translations or other types of reprinting: you may republish this image anywhere without any sort of restriction; I place it in the public domain. I just suggest that you make sure to include a clear translation of the disclaimer that the author is not an expert, and that anyone potentially affected by Fukushima should always defer to the directives of regional health authorities.
- I'd say you're in the clear. It's not a very good chart for thumbnail display in an article, but there's a lot of data to convey. —INTRIGUEBLUE (talk|contribs) 07:48, 21 March 2011 (UTC)
There's already a radiation dose chart
There's already a radiation dose chart on this article: Orders of magnitude (radiation). It seems wiser to take radiation dose information here and move it there, than to start up another chart here. After all, this article is about "sieverts", which is a unit of radiation. I don't think you'd get a list of how tall things are in an article on "meters". (I could be wrong - I haven't checked.) 126.96.36.199 (talk) 04:26, 22 March 2011 (UTC)
- Yes, that is Randall's chart - it appeared after the above discussion. I still think we should avoid the wiki self-reference in the chart source. Perhaps a thumb image could be used on Sievert page, as the concept is not as readily understandable as height or meters. TGCP (talk) 21:26, 22 March 2011 (UTC)
Radiation is measured in becquerels. The sievert is not a unit of radiation. It is a unit of radiation dose. Would you say the amount of energy emitted by a light bulb was the same thing as the number of lumens reaching an object that it illuminated ? Until contributors get this basic sorted, there is not much hope for a coherent article. Interestingly, you are right, the wikipedia article on "metre" does not give a list of how tall things are. Perhaps this is because everyone knows, roughly, what a metre looks like. Certainly, those who don't, once they are given the equivalent in inches, can visualise it. Many people have only learnt the word "sievert" since Fukoshima, and so they need to know what it means in everyday terms. Also, with a metre, you can mark two points on the ground, and say, "the distance between these two points is a metre". How do you do that with a sievert ? Fuhndhu (talk) 23:06, 4 April 2011 (UTC)
- Randall's chart is nice and interesting but contains inaccurate data, very crude approximations, and wild guesses. For example, the radiation dose for "sleeping with someone" is probably zero: the 1.3 MeV beta radiation from the 40K in one body can travel only ~5mm in water, so very little of it can reach another person's body. (Or maybe even negative, since the other body will provide some shielding from ambient radiation.) Also the infamous "eating a banana" may be 2 orders of magnitude less than the 0.1 uSv value given there. (The latter was computed using a conversion factor from an EPA table that applies to an intake of pure 40K but not to natural potassium.)
Thus, Randall's chart is far from being an authoritative, reliable source. Given the current importance of the topic, we should not use that chart in Wikipedia, lest readers think that those numbers are correct. Jorge Stolfi (talk) 15:21, 8 June 2011 (UTC)
- Adding to the previous point, Randall's chart contains the warning: "I'm sure I've added in lots of mistakes; it's for general education only. If you are basing radiation safety procedures on an Internet PNG image and things go wrong, you have noone to blame but yourself". — Preceding unsigned comment added by 2003:45:EE27:3801:18A9:8877:C45A:AA10 (talk) 22:05, 5 January 2014 (UTC)
Whilst visually it is an appealing way of getting a simple message across, there are several issues which others have pointed out. For me the most glaring error is the completely incorrect statement that the sievert is the unit of absorbed dose in the opening text. This is incorrect and going to give a really confusing message. Can the orignal author modify, or are we starting from scratch with a new one? I think this chart is great medium, but needs to be made credible. How to do this? Just blank out the opening text?Dougsim (talk)
The single dose for mammogram is wrong
I have noticed that in the "single dose examples" section, there is a mix-up of using equivalent doses and effective doses: the dental x-ray dose and the mammogram dose are stated as equivalent doses (see the reference) whereas the CT doses and the radiation limits used effective dose (ie whole body doses). This may for example cause the reader to believe that having a mammogram is associated with the same cancer risk as (approximately) a brain CT. For the mammogram example, the breasts receive 3 mSv, but the effective dose is instead 3 x 0.05 mSv = 0.15 mSv and this should be the value that is used for comparisons (see also http://en.wikipedia.org/wiki/Effective_dose) Tobbel swe (talk) 09:52, 22 March 2011 (UTC)
- For example this article dx.doi.org/10.1148/radiol.2481071451 (Mettler et al. Effective Doses in Radiology and Diagnostic Nuclear Medicine: A Catalog, July 2008 Radiology, 248, 254-263.) finds an average effective dose of 0.4 mSv based on reported doses in the litterature. Tobbel swe (talk) 09:09, 23 March 2011 (UTC)
Examples and Fukushima
This article is about the sievert. We have numerous examples do draw from all supported by multiple reliable referenced sources. We do not need to include the latest reported measurements from the Fukushima I nuclear accidents, especially if those figures are only supported by a single source, or non-English sources, or if there is any uncertaintiy about their accuracy.--Pontificalibus (talk) 21:07, 24 March 2011 (UTC)
- Furthermore the article currently states the highest reported numbers from fukushima being 8217 mSv/h while both linked sources say it's 1000 (which was later on denied anyway). There's almost no sources for those 8217 mSv to be found. Some indicate that those 8217 may have initially been a translation error between 8.217 and 8,217 and that it was actually only 8 msv. Should be corrected by someone who can. —Preceding unsigned comment added by 188.8.131.52 (talk) 15:42, 28 March 2011 (UTC)
The Fukushima incident has caused a lot of old people (like me) wondering what a sievert is.
When I was young and carried my slide rule uphill through the snow both to and from school we measured radiation exposure in rems. The Fukushima incident is a opportunity to introduce this SI unit to us old hippies who have not kept up with nuclear medicine. So, when the article implies that radiation is measured in rems in the United States, there is an oppotunity to popularize the SI unit. I never edit an article unless I have an exceptionally high understanding of the topic. Obviously, this case does not meet that standard, but I do encourage those of you who know more than I do to do so. — Preceding unsigned comment added by Mikesartin (talk • contribs) 04:33, 26 March 2011 (UTC)
A lot of people would like to learn more about the stochastic effects of exposure to various sievert levels. How much does your risk of fatal cancer rise from exposure to one sievert? What are the cumulative risks for the heroic workers at the Fukushima site? 184.108.40.206 (talk) 13:45, 29 March 2011 (UTC)
Possibly Incorrectly Quoted Value for Banana Equivalent Dose in Sv (discrepancy of one hundred times)
It seems that there is a discrepancy of 100 times in the value of the dose received as a result of eating one banana, as quoted in this here article and as quoted in the article on Banana Equivalent Dose (BED). This here article states it is 0.0001 mSv, the article on Banana Equivalent Dose states it is 0.001 μSv.
Explanation: this here article states that
- ---Quote begins---
- Eating one banana: 0.0001 mSv
- ---Quote ends---
The article on Banana Equivalent Dose (BED) states that:
- ---Quote begins---
On average banana contains about half a gram of potassium. Therefore if a typical person (70kg) is exposed to all of the radiation coming from one banana then the dose they will be absorbing is of order 10-13 watts per kg (or gray per second). Since 40K decay emits an electron or positron, the weighting factor of 1 is used to quantify the basic biological effect; the equivalent dose rate is of order 0.0001 μSv per hour.
A person's body maintains potassium under homeostasis, at a fairly constant level. Therefore, eating an extra banana will not cause more potassium to be assimilate into the body than would otherwise have occurred. Instead it will cause the body to excrete potassium more quickly. Because the half-life of 40K is so long compared to biological time-scales and because the ratio in food is the same as that in the body, the isotopic ratio will stay the same. Therefore, eating a banana will only cause a temporary increase in the quantity of radioisotope enclosed by the body. Estimating that it takes an average of 8 hours to excrete excess potassium that was consumed from one banana, the total additional dose of radiation will around 0.001 μSv.
- ---Quote ends---
I propose that a competent editor checks again the facts and corrects one of the two articles (it most likely will be this article, since the article on Banana Equivalent Dose quotes the calculation method, which is unlikely to be incorrect, from what I can make of it.
- I've commented on that article's talk page at Talk:Banana equivalent dose#Apparent Original research vs. WP:V and WP:DUE. Some reliable sources which support an assertion that a BSD is roughly 0.1 microsievert are mentioned in that talk page comment. Please note WP:CIRCULAR. WP articles are not reliable sources. The content of WP articles is not to be relied upon. Wtmitchell (talk) (earlier Boracay Bill) 09:18, 28 March 2011 (UTC)
Duplication of Q/N values
The table "Equivalency Weighting Factors" in the "Definition" section is a duplication of the "Q values" and "N values" sections. Should one of them be removed? 220.127.116.11 (talk) 11:58, 29 March 2011 (UTC)
Mixed quantity and unit equations
Please see: BIPM SI brochure page No. 69. for name: dose equivalent, symbol: H, unit: sievert, its symbol: Sv
What is the background radiation for a marine organism (deep water/shallow water) or a human swimmer/diver? One source tells me granite or coffee is 1000 Bq/kg whereas seawater is 10,000 Bq/kg. Correcting for density, I'm guessing the marine background is x3 the terrestrial background, but you'd also need to correct for Q. Most organisms on the planet are marine, so marine background is a useful reference point. — MaxEnt 20:41, 3 April 2011 (UTC)
A sievert is not in any way a conclusive measure of any actual radioactive hazard !
In recent days radioactive hazard has become a major topic of discussion world wide. The attention the subject gets is mainly due to the Fukushima nuclear situation, that triggered a global panic, overshadowing the natural disaster that caused it. The media have been very active in informing the population as best they could, but clearly not in respect to the actual hazard. Processed results of measurement were expessed in sievert value and presented to support the story.
What is not generally understood is the fact that a sievert is not at all meant to be used like that. A sievert result is primarily a policy instrument, meant to give decision makers something to guide and justify their decisions by. It is not in any way a conclusive measure of any actual radioactive hazard. There is no such thing as a 'sievert meter'. Presenting it as if it were a straight measure result is highly misleading. It is the result of a calculation on the basis of a number of subjective assumptions, adding together the presumed effect of many entirely different sources of various kinds of radiation. It's like adding apples to oranges to bananas to cherry pie in desperate need for a result. This is one of the reasons why the results seem so confusing at times.
Since Wikipedia's sievert article is one of the most frequently visited pages in search of understanding the unit, by many who can't read the value of the unit out of the article, this should actually be noted in the articles very first line. Futhermore the exact significance of the unit should be calculated statisticly, envolving more complex statistics than i can provide. What is known is that this significance is way lower than media presentation suggests, publicly spreading a sense of safety that is not justified by the calculated result.
- That's a good insight, if valid, and it may very well be valid. Its validity, however, needs to be established not by forceful talk page argument but, rather, by citation of reliable supporting sources. Wtmitchell (talk) (earlier Boracay Bill) 11:38, 8 April 2011 (UTC)
This article really needs at least a brief mention of cancer risks associated with different exposure levels. Shame that there is so much controversy (on wikipedia) about that. IDK112 (talk) 05:44, 12 September 2011 (UTC)
Conversion to rem in the lead
The lead section should include a conversion factor to rem, just like the inch, kilogram, etc., include the conversion to other common units in their lead. I realize that there is already a section on conversions, but it is normal for the lead to summarize the most important points of the article. See MOS:LEAD--Yannick (talk) 18:39, 11 May 2012 (UTC)
- But metre does not. In my opinion it is better to give only the definition. It might make some sense to include conversion to another unit in the lead, if that unit is expected to be much more familiar to a large group of readers. I doubt very much if that is the case for the rem. People that don't know sievert will generally also not know rem. −Woodstone (talk) 05:59, 12 May 2012 (UTC)
- The metre article does too! Look at the box on the right hand side of the page, in the lead section. It shows conversions to cm, mm, ft, and in. And I assure you from personal experience that the rad and rem are much more familiar to American nuclear workers than the gray and sievert. I'm currently having a somewhat opposite debate on rad (unit). And it is common for American news articles to use rems, while other news sources use sieverts. I easily found examples on Google: this Forbes article versus this World Nuclear News article--Yannick (talk) 11:33, 12 May 2012 (UTC)
- This article is hardly meant for nuclear workers. WP is oriented towards the general public. I maintain the statement that giving a conversion to rem does not give any insight to the overwhelming majority of the readers. We can have a section on conversions and even an infobox, but the alternative unit does not belong in the lead. −Woodstone (talk) 11:51, 12 May 2012 (UTC)
- Can we put the infobox in the lead, like the other unit articles? An overwhelming majority of english language readers on Wikipedia are Americans who are much more likely to see rems in their versions of the news, for example in Forbes magazine. And I can tell you that I've personally known many nuclear workers who have gone to this article to find out what a sievert is. This article is certainly meant for people who have an interest in learning more about radiation, and the ones who are from the USA, nuclear workers and others alike, are much more likely to be familiar with rems.--Yannick (talk) 12:47, 12 May 2012 (UTC)
I don't know what 2002 change you're talking about; I see a questionable mention of a 2002 change in the article, but that's an entirely separate issue that I've had nothing to do with. (Yannick)
- The weighting factors for different forms of radiation and for the body parts were modified for the sievert in 2002. My question is: was the same modification performed for the rem? If, not they can no longer be converted to each other. −Woodstone (talk) 12:16, 13 May 2012 (UTC)
- Oh I see. You're talking about ICRP publication 92 (2003). I'm sorry, but now you're displaying an important lack of knowledge about the subject at hand. The rem is a unit, and it is defined by NIST as 0.01 Sv in Federal Register 63. That same definition, 1 rem = 0.01 Sv, is repeated in the NRC regulations. I'm not aware of any serious organization that challenges this definition of the rem. The weighting factors you're talking about are not conversion constants from one unit to another. They are basically regulatory safety figures that vary depending on the situation, and different regulators have mandated (or recommended) different sets of weighting factors at different times. But relating that back to a definition of the rem is kind of like asking if the mile is still equal to 1.852 km after a country changes its speed limit from 55 mph to 100 km/hr. The answer is an emphatic yes.--Yannick (talk) 13:06, 13 May 2012 (UTC)
- Not quite the right answer. The weighting factors are an integral part of the definition. The same physical radiation will result in a different equivalent dose measured in sievert before and after the modification of the definition. If the same modification would not have been done for the older non-SI rem, it would no longer be 0.01 sievert (and worse, a single conversion factor would not exist). But as I meanwhile found, it appears that indeed the rem was modified as well, see this table in the SI brochure. −Woodstone (talk) 13:42, 13 May 2012 (UTC)
- I think you need to take a look at the regulatory documents on radiation protection, things like ICRP 92 and ICRP 103. You are correct in that the same absorbed dose will result in a different equivalent dose depending on which regulatory framwork is used, in the same way that the same volume of gasoline will give you a different distance travelled depending on which car is used. But that is not part of the definition of any unit of measurement. I challenge you to find a reliable source supporting your claim that the weighting factors are an integral part of the definition of of the rem or sievert. Note that the NRC still doesn't use the same weighting factor for protons as the ICRP, so using your logic the American rem and the American sievert would have no conversion factor to International rem and International sievert. I'm sorry, but you haven't done your homework on this.--Yannick (talk) 14:44, 13 May 2012 (UTC)
- Your last statement is correct. And furthermore, 0.01 sievert (NRC) would not be 0.01 sievert (ICRP). (Check the NRC CFR link I gave above - it uses both sievert and rem with the same American weighting factors.) This does not imply any difference in the units of measurements, only a disagreement about how much biological damage is caused by a given amount of absorbed energy from protons.
- I think I might have figured out where the confusion comes from. That 2002 decision changed the explanation of absorbed dose H -- but it did so by dropping N, not by changing Q. This explanation only ever appeared in the Appendix to the SI brochure, and did not define the values for Q. If you read the 2002 decision carefully, you'll see it did not change the definition of the sievert, nor did it change any values of Q because the CIPM has never published weighting factors or quality factors for ionizing radiation. The definition of the sievert is given in table 3, then and now, and that table says nothing about quality factors or relationship to gray. Does that make sense now?--Yannick (talk) 17:38, 13 May 2012 (UTC)
I have looked at the lead conversion issue in more detail, and I found that infobox we've seen is actually a template specific to units of length. I'm not a programmer, and I'm not sure it would be worth the effort to make a template for radiation units anyway. For non-length measurements, the norm seems to be include conversions to common non-SI units in the text of the lead section, just as I'm proposing. See for example second, Candela per square metre, and kilogram. And finally, I would point you to this discussion, earlier on this talk page.--Yannick (talk) 17:47, 12 May 2012 (UTC)
Propose moving most material out to other pages
As I look at this page, it really doesn't look like an article about a unit of measurement to me. It looks like haphazard notes written by someone researching radiation dosimetry. Most of the stuff about dose equivalent, effective dose, Q factors, etc., is really about those quantities, not the unit. Keeping it here helps promote confusion between quantity and unit which is already a common problem in radiation measurements. I propose moving most of this stuff out to pages like equivalent dose, effective dose (radiation), relative biological effectiveness, dosimetry etc. As to the examples, I can see why we need a few examples to get a sense of what the unit represents, and a sense of scale, but there are way too many here. Does anyone have concerns with this plan?--Yannick (talk) 01:00, 17 May 2012 (UTC)
- The problem is that without an explanation of D and H and their relationship it is not possible to give meaning to the sievert. Before my first edit, the article actually said "1 Sv = 1 J / kg • [w]". So in my opinion removing those parts will make the article useless to understanding the sievert. −Woodstone (talk) 09:02, 17 May 2012 (UTC)
- I agree with you that we need a brief explanation of the difference between absorbed and equivalent dose in order to explain why the sievert exists and where it is used. All I'm saying is that we don't need to go into so much detail about how the calculation is done, or even to provide the radiation weighting factors. For example, there's a whole section in there about effective dose calculation - what does that add to the understanding of the sievert unit? It's like putting the formula for the volume of a sphere in an article about the litre. The sphere formula actually belongs in the volume article, just as the effective dose formula should be moved out to effective dose (radiation).
- I hope you're not still trying to claim that the weighting factor is somehow part of the definition of the unit. Take a look at the publicly available extract of ICRP 103. It says "the unit for the equivalent dose is the same as for absorbed dose, J kg-1, and its special name is sievert (Sv)." [boldface mine.] Looking at the SI brochure, which is the primary definition of the sievert and gray, we find that they are both "special names" for the J/kg. "The special names and symbols are simply a compact form for the expression of combinations of base units that are used frequently..." (International Bureau of Weights and Measures (2006), The International System of Units (SI) (PDF) (8th ed.), ISBN 92-822-2213-6, archived (PDF) from the original on 2017-08-14) Mind you, they are not interchangeable, as the SI brochure says they are used on different quantities, absorbed dose and dose equivalent [sic]. But the two units are mathematically equal: Gy = J/kg = Sv --Yannick (talk) 13:55, 17 May 2012 (UTC)
- Woodstone, I tried. I spent a lot of time discussing this with you, and provided plenty of examples and reliable sources to support my views. You have provided little in the way of reasoning or citations. At each step, I gave you plenty of time to respond and discuss. In the end I had no choice but to be bold. I hope we can get over any hard feelings here.--Yannick (talk) 18:34, 18 May 2012 (UTC)
Now the article is full of examples of quantities of sieverts received, but no one will have a clue how these are measured. Why not just re-add the factor tables? What is the harm? It would make the article so much more useful for the average reader. The mentioned Q and W in the history sections are completely hanging in the air. I had given the references for these long ago. −Woodstone (talk) 10:20, 19 May 2012 (UTC)
- The tables aren't gone you know, (except for the non-human one which was unsource and dubious,) they're still there on equivalent dose, effective radiation dose, [[dosimetry], etc. So if someone wants to know how to calculate those quantities, they can follow the hyperlinks to more relevant articles like dosimetry. But you know, I'm wondering why the average reader who comes to the sievert page would want to know how to do dosimetry calculations. I think the average reader who looks up sievert would have seen the word in newspaper articles, or gotten it from his or her doctor, and wants to know how worrying a sievert is. I don't think they'd be looking for a bunch of poorly explained table to try to work backwards to what the original absorbed dose must have been. And the tables are almost useless in a power plant situation, which seems to be of most interest to most readers, because the environment is dominated by whole-body gamma where all the weighting factors are all 1. (Oh yeah, did you know that there's more than two weighting factors?) You get your approximate dose by reading the dose rate on the metre or the posted sign or the newspaper article, and multiply by the amount of time you're going to be in there, and that's as much as most people want to know. Or you just wait for your next dosimetry report, and then the big question on your mind will be "what does it mean?" not "how did my green man calculate these figures?" And when that happens, my colleagues come to me for explanation, and then they tell me I should rewrite the Wikipedia article, because the old one only confuses them further.
- But the general principle is about keeping the article on topic. Look around at the other unit articles. The litre and cubic metre article do not describe how to calculate volume. The watt article does not describe how to calculate power (physics). The joule article does not describe how to calculate potential or kinetic energy. There's a distinction between the unit of measurement and the quantity measured, which seems to be lost on you. The formulas and methods (and the tables, if they're non-dimensional) that are used to calculate the quantities will be the same regardless of which units you use, and those things belong in the quantity articles. I would calculate effective dose or committed dose in exactly the same way with the same equations and tables regardless of whether I started with measurements in gray or rad, and regardless of whether my customer wants the output in rem or sievert. The weighting factors are different depending on the regulatory environment you're in, but they are not specific to any system of units.
- So in answer to your question "What's the harm?" I would answer that those tables promote confusion between the quantity and the dose for the less-informed readers like yourself, (no offense, we all started there,) and they are in the way of quickly getting the sought-after information for more-informed readers like myself and my colleagues.--Yannick (talk) 19 May 2012 (UTC)
fusion reactor waste: 90 MSv/yr?
Was somewhat surprised by this line in the dose example table
- 90 MSv/yr 10 kSv/h waste components from fusion reactors
That is a massive dose, especially for a power source that's supposed to produce little to no long-lived radioactive waste. So I decided to read the cited source, but I can't really find any basis for this figure in the chapter being referenced. Was this deduced somehow?
- Oh come on. I even gave you the page number in the cite: page 318. "It is important to develop advanced rad-hard RH equipment that can handle components presenting dose rates up to 10000 Gy/h (10000 Sv/h) or more. This equipment is already needed for removing the replaceable components from the vacuum vessel of a tokamak and moving them to the hot cell." But yeah, you've picked up on a common game that the nuclear industry plays with quantities of radioactive waste. Don't like the radioactivity? We can dilute it. Don't like the volume? We can concentrate it. We're here all night, folks.--Yannick (talk) 18:44, 15 June 2012 (UTC)
- It seemed a notably high figure (even if not plainly invalid) so I checked the cite as well. I find the reference is (probably) valid, but selective and possibly misleading. From page 310: "In the U.S. ARIES studies (ARIES Project), the technical feasibility of recycling is based on the dose rate to advanced RH equipment capable of handling at 10 kGy/h or more (El-Guebaly et al, 2008). Such dose rates are present at routine operations in the reprocessing of fission reactor fuel and at the outside surfaces of radioactive goods during their weighing, welding, cleaning, contamination monitoring, and transfer to containers." Yes, it's probable that doses exceeding 10 kSv/h will be involved in handling spent components for fusion reactors. It's still largely theoretical, (currently only a few experimental reactors are in use, and very limited processing has occurred so far), but the real numbers are likely to be close. However, the source claims these expected dose rates are comparable to (or possibly exceeding) equivalent rates in existing fission reactor systems. I don't see a clear statement that the activity of fusion reactor components are likely to be higher. --Robert Keiden (talk) 18:20, 19 July 2012 (UTC)
- But there are a few other games at work here, and a reason why "a power source that's supposed to produce little to no long-lived radioactive waste." could still be argued. Fission waste is largely chemically reactive light elements with medium to long half-lives. Fusion waste is largely expected to be relatively stable metals with short half-lives, and management includes storing them for short terms (<100 years) and then recycling. Regardless, perhaps change the article to "waste components from nuclear reactors" or "waste components from both fission and fusion reactors" because its more comprehensive? --Robert Keiden (talk) 18:20, 19 July 2012 (UTC)
- Well, I certainly didn't mean to mislead or start a proxy debate on fusion power. I traced the book citation to a powerpoint presentation that cites this paper. This paper predicts theoretical neutron activation of around 10 kSv/h for the first wall of a possible PPCS fusion reactor, lasting for a year or so after shutdown. For comparison to fission waste, it says "Bearing in mind the differences, the example exists of fission reprocessing installations where operations on active waste with up to 104 Sv/h contact dose levels are routinely performed; singular examples at even higher doses exist, ." I am not clear on what examples this is referring to, and could not immediately locate the reference. I suspect that this may refer to some odd artificial situations, not ordinary fission reactor waste. I am somewhat skeptical about the broader claim of El-Guebaly about reprocessing of fission waste and would prefer to see a better source. I have no clear source saying that the activity of fusion reactor components is likely to be higher, but i have not seen such high numbers for fission reactors. See for example this abstract which resorted to an artificial experiment to produce such radiation levels, explicitly for the development of fusion components. I would agree to adding the words "theoretical" and "future" to our example, but I would ask for a better source before ascribing this radiation level to fission reactor waste as well.--Yannick (talk) 01:10, 31 October 2012 (UTC)
- You need to put time scales beside the fusion source. The dose in Sv (if you climbed into the reactor soon after its turned off to kill yourself) will be due to neutron activation of the reactor walls, which depending on the material used and its thickness - Lithium, Carbon, Steel and or Tungsten could be negligible or high. The tritium generated in the walls(if its not used as fuel for some bizarre reason) will have completely decayed away after ten half lifes which is after ~ 120 years there will be 0.1% of the tritium left for example. It will not be a long term hazard of the same timescales as fission spent fuel is.
controversy, hypothesis, falsification and exploitation
According to Christopher Busby, at low doses, and dose rates, there is much less data, and much more controversy, regarding the possibility of cardiac and teratogenic effects, and the modelling of internal dose. See the linear no-threshold hypothesis—however, this hypothesis was never based on true "low dose" studies and Busby was discredited by the British Health Service for data falsifications and exploitation of Japanese parents after Fukushima emissions (2011).
- The linear no treshold hypothesis is Busby's theory that has been discredited and was based on data falsification? Or it is a hypothesis supported by the British Health Service that is not based on true studies and when Busby revealed this the British tried to discredit him with false allegations? Either expand it or remove it, no use in having a cryptic statement that mentions controversy, hypothesis, falsification and exploitation without explaining any of these. Ssscienccce (talk) 03:21, 7 October 2013 (UTC)
Absorbed dose is the default... Need a cleanup
I went and added the U.S. regulations on maximum equivalent doses permitted... And by copying these regs I noticed that the regs are very specific on how they state the limits. They are in the habit of correctly stating, for example,
- The total effective dose equivalent being equal to 5 rems (0.05 Sv)
Notice that those four words all convey the proper meaning to the 0.05 Sv specific limit. We are not left wondering if the limit would pop up in grays or mR, etc. The limits had to be in Sv or rem. It's funny that the spec says "rems" but that is only slightly sloppy.
But browsing through the chart of the article, I notice that we say this sloppy sentence:
- 80 μSv: average dose to people living within 16 km of Three Mile Island accident
Well, that is not very specific. Do we mean their "dose" or their "total effective dose equivalent"? Dose to me means the Absorbed dose and is measured in grays or rads. So by not saying "equivalent" I fill in the "absorbed" part and the chart gets confusing. The U.S. wording especially shows me that the word dose by itself means something that needs to be modified... they put the "equivalent" adjective after the noun... "dose equivalent." I think the article would be better if the word "equivalent" was used adjacent to "dose." Why have a reference work like Wikipedia if it is going to use lazy or sloppy wording?
Furthermore, why did we quote an "average dose"? Shouldn't we care about individuals of the public, whereas averages work out to be dangerous when we are talking about people's health? I seem to think that the word "average" indicates to me that someone synthesized a stupid and worthless statistic. I want to know the highest dose equivalent received by a member of the public. Obviously if two people glued to the fence got 50,000 times the dose equivalent of the guy sleeping in his basement 10 miles away, I want to know about the men on the fence. I like to saw logs! (talk) 04:24, 10 December 2013 (UTC)
Difference between gray and Sievert is that Sievert is not absorbed dose BUT effect of absorbed dose, that is why the tables have different conversion factors for different radiation type and organs. I also note that there is no mention of that there is a massive difference in effect of doserates, I can understand that there is problem, I have not found any good source about that but it is quite different resultat wheather yu recive 1 Sv in 5 minutes or spread over 10 years. The first have a high death-risk, the second have good chance of not making any messaurable damage.Seniorsag (talk) 16:17, 22 July 2015 (UTC)
Is this Correct ? I suspect not !
"If the equivalent dose is uniform throughout the organism, that is, if the radiation source equally impacts on the entire surface of the body, it will be equal to the body tissue specific effective dose."
It seems to me that there are several problems here.
1) The concept of uniformity. I do not think that uniformity over the surface of an organism is intended here. I suspect that this should read ".. that is, if the radiation source has delivered equal energy to equal increments of mass throughout the body...". I have changed the text to the latter quote.
2)As I understand this, to get "body tissue specific effective dose" from equivalent dose, you must multiply the former by a tissue weighting factor which is generally not unity, so, even if the dose is uniform throughout the body, the "body tissue specific effective dose" will not equal the effective dose. — Preceding unsigned comment added by 18.104.22.168 (talk) 15:10, 30 January 2014 (UTC)
- The tissue weighting factors add up to one, so if all tissues receive the same equivalent dose by mass, the effective dose is the same as the equivalent dose. −Woodstone (talk) 16:34, 30 January 2014 (UTC)
Thank you - I suspected that this is the answer, which is why I did not alter the original text. However, I feel the point should be explained. I have changed "organism" to "human body", which is the organism for which the usual weighting factors add to 1. However, I now find another problem. If what Woodstone has said reflects the thinking of the original author, should not "body tissue specific effective dose" be changed to "whole body effective dose". Am I correct in understanding the former phrase to relate to specific tissues, rather than the whole body ? If, on the other hand, we understand "body tissue specific effective dose" to mean what it says, then a weighting factor is needed. — Preceding unsigned comment added by 22.214.171.124 (talk) 08:50, 31 January 2014 (UTC)
I am beginning to feel that this article is very defective, reflects extremely wooly thinking, and is in need of careful review in order to weed out careless errors of wording. I now question this: "...while the sievert is used to express the biological equivalent dose to human tissue". Surely, in view of the above, this should read "....the biological equivalent dose to the human body".
The sievert unfortunately seems to be one of the most poorly described units there is. I have made quite a few changes to the article based on ICRP 103 (which runs to over 300 pages) and other learned papers, and brought in a number of additional issues that need consideration when talking about the sievert, which has been in gestation for a while now. Hopefully these will have addressed your points. If not please put comments here. Dougsim (talk) 14:04, 7 February 2014 (UTC)
Partial Body Irradiation
The examples list includes dental X-rays, mammograms, and CT of the colon. In these cases only part of the body is irradiated. Do the quoted figures of dose relate to the mass of tissue irradiated (i.e in calculating J/kg, is the mass used that of the irradiated tissue only), or is the dose an average dose for the whole body, the mass used in the calculation being that of the whole body ? Clearly the former form of calculation will give a higher figure for dose than that obtained if the whole body mass is used. Unless this point is made clear, the figures given in these 3 cases are meaningless. To clarify this, could someone please explain how dose in Sv is calculated in the case of a single dental X-ray ? AJS
This is the expression of the effective dose, which is not wholly dependent on how much is irradiated. What is important is the irradiation received and its effect. All effects are summated to an overall expression of risk, which is the effective dose. This is shown in the graphic. It should be noted that the ICRP figures are averages taken over the world population based on decades of research, and are conservatively fixed.
Operational and protection quantities
I have put operational and protection quantities and their relationship to physical quantities and instrument measurements into the article in order to tie up the many loose ends and to make the article coherent. Although the article may appear more complex, this is a true reflection of the complexity of use of the sievert.
I have added the CIPM definition and tied this in to the work of the ICRU and ICRP. I have devised a graphic for this based on the work of others leading back to ICRU report 57, as there are some difficult concepts. I have added in tissue effects for completeness but tried to avoid excessive duplication. Dougsim (talk) 13:48, 7 February 2014 (UTC)
There is some confusion here! The conversion factor 1 Si = 100 REM is aproximately true, BUT since they have modivied the wheigt factors a little it is not compleatly true. For mormal use it is good enough, but not for precision use. Seniorsag (talk) 15:21, 15 July 2014 (UTC)
I note that although there's a reference to the RadSafe mailing list, we have no article on it. We probably should have and soon will I hope. I've redlinked to it in anticipation. Andrewa (talk) 21:29, 9 January 2015 (UTC)
We've got "ionising" and "ionizing" all over the place. As of January 2016, it was completely "z" except for one "s", but since then a bunch of "s" have crept in. There's no nationalistic component to the article's topic itself, so I assume we should go with original form and inertia. I plan to flip it all to "s" in a day or two unless someone disagrees (or beats me to making that edit:) DMacks (talk) 08:06, 14 December 2016 (UTC)
- Go for it! AFAICT, it stayed British from its original off-the-wall wrong stub to actual article status. Kolbasz (talk) 13:15, 15 December 2016 (UTC)
Dose examples revisited
Because someone reverted it for some reason: The "Dose examples" section is currently an entirely excessive listing of unexplained statistics: it is a collection of doses and dose rates that do absolutely nothing to further the understanding of the sievert as a unit. This is a unit that's intended to quantify stochastic risk - in other words, it isn't meant to represent deterministic effects. But that list is just item after item of deterministic (ARS, death) outcomes. You could list all the doses received by anyone ever, but it would not help anyone understand what the sievert is. Kolbasz (talk) 01:27, 11 February 2017 (UTC)
- I am the one who undid your edit, I would like a consensus on what should and shouldn't be included in the section. Also please do not revert then talk that is not what WP:BRD is for. If your edit is undone, you talk about it here first we reach a consensus then the change is either made or not made. - Knowledgekid87 (talk) 01:36, 11 February 2017 (UTC)
- The section is called "dose examples", deaths and the amounts received can explain the effects of the Sievert. This isn't a dictionary so we cant just provide a definition of what it is. - Knowledgekid87 (talk) 01:39, 11 February 2017 (UTC)
- Do you have any actual arguments for keeping it, more than "I like it"?
- The first step in cleaning up an article is cutting out the cruft. Then you can start cleaning up the rest. And this... is pure cruft. If this were, say, the article on Celsius, the equivalent of the "Dose examples" section would be a "Temperatures" section full of entries like:
- -4 °C - lowest average monthly temperature in Ystad, Sweden
- 18.1 °C - maximum recorded temperature on June 2, 2015 in Toronto, Canada
- 40 °C - typical temperature in close proximity to someone rubbing their hands together really fast
- 334 °C - operating virtual junction temperature of an NE555 chip
- 0.5 µS/cm - typical conductivity of distilled water at room temperature (20°C)
- None of those in any way help the reader understand the Celsius. Some are hopelessly vague with subjective qualifiers. Some aren't even listing temperatures, but are measuring something else completely. The rest are at best just useless trivia.
- If removing crap like that is in any way controversial, then... I'm done. I'm done with this article, and I'm done with Wikipedia. Kolbasz (talk) 23:25, 15 February 2017 (UTC)
Has there been any proposal to include the wisdom about nonlinear effects on the measurement of radiation effects? There are several works on low-dosage effects, like . How about the amplitute form of the radiation applied - does it make no difference if the radiation occurs in several short higher-energy bursts or in one slight sinus-formed curve, as long as they have the same integral value? Any links to works on this subject are welcome. --Bernd.Brincken (talk) 10:44, 15 March 2017 (UTC)
Changes to graphic
I am going to revert the protection quantities graphic link back to the diagram I wrote a few years ago, which is a truer representation of what the ICRP/ICRU means. Effective dose does not exist at tissue or organ level for multiple organs. Effective dose is the summated value of the double-weighted quantities.
See the following explanation of this difficult area published in 2013; in this explanation the contributions to the effective dose are best described as equivalent organ or tissue doses in the most recent terminology.
From: "Radiological protection issues arising during and after the Fukushima nuclear reactor accident Abel J Gonzalez et al. Journal of Radiological Protection vol 33 (2013) 497–571
2.3.2. The changing names of the radiological protection quantities.
The names used for the radiological protection quantities have evolved. ICRP Publication 26 (ICRP 1976) and
its amendment issued by the ICRP’s 1978 Stockholm statement introduced and defined the
quantities ‘organ or tissue dose equivalent’ and ‘effective dose equivalent’. ICRP Publication
60 (ICRP 1991) changed the terms to ‘equivalent dose in a tissue or organ’ and ‘effective dose’.
The reason for the change was that ‘the weighted dose equivalent (a doubly weighted absorbed
dose) has previously been called the effective dose equivalent but this name is unnecessarily
cumbersome, especially in more complex combinations such as collective committed effective
dose equivalent’. ICRP Publication 60 also states that ‘the Commission has decided to revert
to the earlier name of equivalent dose in a tissue or organ’. However, searching for the name
‘equivalent dose’ in previous ICRP reports failed to find clear evidence for this statement.
For example, in ICRP Publication 2 (ICRP 1959) the name ‘RBE dose’ was used and in
ICRP Publications 6 (ICRP 1962) and 9 (ICRP 1965) the name ‘dose equivalent’ was used.
Therefore, the coexistence of the names of equivalent dose and dose equivalent appears to be
due to changes introduced by the ICRP in Publication 60. The coexistence of the two different
names for the same quantity has added confusion and misunderstanding within an already
complex dosimetric system for radiological protection. Finally, ICRP Publication 103 (ICRP2007a)
uses equivalent dose without the specification ‘in a tissue or organ’ which can add
to misunderstanding with effective dose if the quantity is not clearly specified since the unit,
sievert (Sv), is the same.
Why the two are different ? I wrote "810 nSv/h avg Next to the Chernobyl Nuclear Power Plant sarcophagus ", as can be seen in the References. But when I watch this video, it tells another data ? Check  at 5:36 . The time different between the two pictures is five years, but I assume it's not causing the different in the data .Eliran t (talk) 22:51, 24 June 2019 (UTC)
- Good point. Maybe the Chernobyl New Safe Confinement that was installed in this time plays a role in the lower dose rate levels? I am not sure. --Ita140188 (talk) 18:57, 27 June 2019 (UTC)