Talk:Decay chain

A table

In rewriting Radioactive decay, I found the following table, reproduced here complete with plaintext label. Being of rather limited knowledge about radioactive decay, I have a few questions to ask.

The three such naturally occurring series are shown in the following table:

Natural radioactive elements

Series	Starting Isotope	Half-life (years)	Stable end-product
Radium	U-238	4.47×109	Pb-206
Actinium	U-235	7.04×108	Pb-207
Thorium	Th-232	1.41×1010	Pb-208

• I see that the decay chains listed are those with nucleon numbers congruent to 0, 2, and 3 mod 4. Where's the series congruent to 1?
• In the same vein, why are only heavy-element chains listed?
• How are the "starting isotopes" determined? I see that these three isotopes have very long half-lives, but surely they must be, for their part, decay products of some other nuclides.

--Smack 19:47, 22 Dec 2004 (UTC)

I don't claim any expertise in the area, however, I'm not sure I understand your question.

• What do you mean when you say a nuclean number is "congruent"?
• All radioactive isotopes will have a decay chain. For lighter elements, the decay chain is typically short; a single beta emission would result in a stable product
• All radioative isotopes have decay chains. A comprehensive table to decay chains would list them all. If you're asking how any radioactive isotopes came to be radioactive in the first place, that's a separate question.  :-) Samw 04:03, 29 Dec 2004 (UTC)

• Congruence of integers is defined in Modular arithmetic. An alpha decay reduces the nucleon count by 4, and a beta decay leaves it unchanged. Hence along a decay chain all nucleon counts are "congruent to each other modulo 4". What Smack is asking is why there is no chain listed with nucleon number 237/233/229/...

• Thanks for clarifying. There is a U237 decay chain. See: http://www.radiochemistry.org/periodictable/gamma_spectra/pdf/u237.pdf However, the half-life is short and this series doesn't occur naturally.

•  
• What he is asking is e.g. how we know U-238 starts the series. That U-238 could itself be a product of <something>-242 (which could be a product of <something else>-242 or <some other thing>-246), which could have such a short half-life that in the final mixture it cannot be detected. -- Paddu 04:38, 29 Dec 2004 (UTC)

• There are <X>-242 that decays into <X>-238: Americium-242 and Plutonium-242. Pu-242 has a long half-life in human terms, but in geological terms, there's none left naturally. So, like the answer to the first question, these 3 are considered the start of the decay chains because these 3 have very long half-lives.Samw 18:22, 29 Dec 2004 (UTC)
• BTW, there's already an article on Nucleosynthesis describing how all elements, including radioactive ones, come to be. Samw 21:26, 31 Dec 2004 (UTC)

I think I understand now. A decay chain is considered important only if it contains a very long-lived nuclide, which (once produced by some process) can act as a continuous source of nuclides farther down the chain. Since neither light-element decay chains nor the U-237 chain contain such a nuclide, they're not listed.

That said, it seems unnatural to name a sequence of unstable nuclides after its least unstable nuclide. Furthermore, IMHO, this whole notion of nucleon-number preservation is unscientific. It smells like it was thought up by engineers rather than physicists. They (we?) often give too little thought to scientific generality and consistency. --Smack (talk) 17:13, 6 Jan 2005 (UTC)

http://members.tripod.com/vzajic/1stchapter.html suggests you're right and that the "actinium series" name was chosen for practical reasons to avoid calling it U-235 series to distinguish it from the U-238 series. Samw 02:19, 7 Jan 2005 (UTC)

Here's a reference that shows all 4 decay chains: http://www.amazon.com/gp/reader/047180553X/ref=sib_vae_pg_179/102-8556324-8260101?%5Fencoding=UTF8&keywords=decay%20chain&p=S05J&twc=24&checkSum=0J4LnZVge9osi%2BmMweCi%2BMsMqE6XDZCnQP3F%2FiebUWE%3D#reader-page Samw 01:17, 19 Feb 2005 (UTC)

Neptunium series

What about the Neptunium series that describes the decay chain of the transuranic elements?--ragesoss 17:21, 22 January 2006 (UTC)

Half-life of Thorium-232

Why is the half-life of Thorium-232 written as 1.405·10^6 a, meaning 1.4 million years? Since this is dramitically less than the age of the planet, shouldn't this be more like 1.405·10^10 a (this is the number claimed in the Thorium article). Since I'm no nuclear physicist, I'd rather point this out in the discussion before I tamper with the article. Felix Dance 15:52, 14 April 2006 (UTC)

Thanks, I've corrected. Samw 19:24, 14 April 2006 (UTC)

Merge from Radioactive decay path

It was suggested that Radioactive decay path be deleted and anything salvagable be merged here. I thought I would dump it here so It wouldn't be lost until I get around to adding it here, or you can add it here ;). The only reason I learned this was to understand how scientists date materials and why no reputable scientist believes the earth is only 6000 years old, as opposed to about 4.5 billion years. I think this is important considering the increasing attacks that pure science has come under from religious and political factions lately in America.

• Radioactive decay paths are an integral part in dating materials. By comparing the relative abundance of various elements in a sample one can estimate its age based on the decay path and half lifes of those elements. Analysis of various Uranium containing Zircon crystals (along with other data) puts the age of the earth at aboout 4.5 billion years. Decay paths are also important in reactor experiments where the elements produced are so short lived that their existence can only be infered by the abundance and type of their decay products.
• Radioactive decay paths are also important in less than geologic scales such as with Carbon 14 which is used in Radiocarbon dating of organic materials. (yet more testable proof that the earth is more than 6000 years old)
• Age of the Earth 4.55 Billion (4.55×10⁹) Years
• Age of the Universe 13.5 Billion (1.34×10¹⁰) Years
• Nuclear Theory : Island of Stability
• Nuclear Theory : Shell Model

Tiki God 14:08, 28 July 2006 (UTC)

Diagram

I added the decay chains diagram -- what do you think? Opinions welcome. — Johan the Ghost _seance 13:03, 25 November 2006 (UTC)

The labels are all messed up -- though it looks OK on my system... :-( So I guess I have to fix it. — Johan the Ghost _seance 13:10, 25 November 2006 (UTC)

OK, fixed. (It seems to be really hard to make an SVG that displays the same in Inkscape and in MediaWiki... :-/ — Johan the Ghost _seance 13:19, 25 November 2006 (UTC)

In the Th-series diagram there is an error in half-live of Ra-224. It should be something like 3,7 days (not years). Can anyone edit the diagram and correct the mistake? Thanks! —Preceding unsigned comment added by Danapit (talk • contribs) 09:53, 4 May 2009 (UTC)

This was fixed some time ago. BatesIsBack (talk) 15:08, 15 May 2011 (UTC)

I'm currently working on a comprehensive Periodic Decay Chart from n to uuo including all forms of decay that I can find, with probabilities, color coding and particle symbols after the first version is completed I will if time permits work on one that is a bit more aesthetically pleasing. —Preceding unsigned comment added by Abyssoft (talk) 17:09, 28 March 2010 (UTC)

ERROR NOTE: In the diagram: Decay chain(4n+1,Neptunium series).PNG,

look carefully, and uranium-233 is mistakenly labeled as U-223.

If you look very closely, you will see that it is labeled as both U-223 and U-233.

U-223 would be very rare to nonexistent, because if any nucleus of it did exist, it would immediately start emitting positrons and going downhill in atomic number that way.98.67.167.211 (talk) 05:29, 4 June 2010 (UTC)

I fixed this when making a SVG version of this. BatesIsBack (talk) 15:08, 15 May 2011 (UTC)

Well, this is a quibble, but ²²³U actually alpha decays to ²¹⁹Th, then ²¹⁵Ra, ²¹¹Rn, ²⁰⁷Po (or ²¹¹At, to ²¹¹Po or ²⁰⁷Bi and then stable ²⁰⁷Pb), ²⁰⁷Bi, and stable ²⁰⁷Pb. Double sharp (talk) 14:28, 3 September 2014 (UTC)

BatesIsBack, great diagrams! What software or script did you use? I'd love to try to make A3/A4 version of the 4 chains as one, but rather not start from scratch. Please ping me on Kalin[AT]safecast(dot)org Kalin.KOZHUHAROV (talk) 14:47, 21 January 2012 (UTC)

a vs y?

I know it's a nit, but is it now standard practice in nuclear physics to use the letter 'a' to mean 'years' instead of 'y'? Obviously 'a' comes from the Latin 'annus' ('year'), but a lot of English-speaking Wikipedia readers might not know that.

Karn 23:39, 25 November 2006 (UTC)

It's kind of sucky, but after much searching, there does seem to be a real basis for this use in science: see year#Julian year. Maybe make the "a" a link to this? — Johan the Ghost _seance 22:14, 27 November 2006 (UTC)

The actual table lists half-lives in units of 'y's, which represent years. The description should say 'y' unless the information in the table is changed. — Preceding unsigned comment added by 68.42.78.153 (talk) 05:44, 8 August 2012 (UTC)

There are 6 tables in this article, of which only the first uses "y". Again, if you want to change them all in the other five, you go, girl. You can do a find-and-replace, but there are a lot of other "a"s that really should be a's, that you have to put back by hand. Enjoy. SBHarris 21:23, 8 August 2012 (UTC)

Cancer

The text states "Thus, radon is a naturally occurring radioactive gas, which is a leading cause of cancer in humans."

I'm not an expert in cancer but I think that Rn attributed lung cancer deaths are about 22,000, where all cancer deaths are about 550,000 and radiation attributed cancer is one of the lowest ranked causes. I think though that lung cancer is the leading death due to cancer, and that Rn attributed lung cancer is number 2 on the list, behind smoking.

Would it more proper to say "Thus, radon is a naturally occurring radioactive gas, which is a leading cause of lung cancer in humans." ?

Jon in Michigan 22:25, 19 June 2007 (UTC)

I've clarified with a reference. Next time, be bold! Samw 00:52, 20 June 2007 (UTC)

Thermal Disintegration

How does thermal disintegration work? I'm describing a situation where a nucleus is heated to the point where it detonates into a cloud free neucleons. I think this occurs around 10¹² Kelvin for helium. Any thoughts? Plasmic Physics (talk) 11:42, 25 October 2008 (UTC)

Total energy?

This is a really interesting article. I have some questions that I think this article should address.

First, it seems that the total decay energy and product mass should be constant across all decay paths. So, for instance,

Bi-212 -> Po-212 -> Pb-208 yields 2252 + 8955 = 11207 KeV
Bi-212 -> Tl-208 -> Pb-208 yields 6208 + 4999 = 11207 Kev

Great. However, check out these two:

Bi-210 -> Po-210 -> Pb-206 yields 1426 + 5407 = 6833
Bi-210 -> Tl-206 -> Pb-206 yields 5982 + 1533 = 7515

I presume something in the Po-210 branch is carrying off the 682 eV, like a neutrino or somesuch. This should be noted in the table.

Second question: You have listed the alpha decay of Bi-213, but not the beta decay. The unlisted beta decay is 97.91% likely, so it should be listed. I would edit the table, except I'm not sure where you sourced your data. If I look at http://ie.lbl.gov/toi/nuclide.asp?iZA=830213, I see 5982.6 KeV listed for the alpha decay, instead of the 5870 listed here. I may be interpreting things differently.

Third question: I came to this article wondering about the relative radioactivity of transuranics versus fission products. After resolving hopefully minor issues like that above (by, for instance, picking the most likely chain), I think you could list a total decay energy for each element. So, for instance:

Pu-242: 57005 KeV (using http://ie.lbl.gov/toi/nuclide.asp?iZA=940242)
U-238: 52021
Th-234: 47751
Pa-234: 47478
U-234: 45281
Th-230: 40422
Ra-226: 35652
Rn-222: 30781
Po-218: 25191
Pb-214: 19076
Bi-214: 18052
Po-214: 14780
Pb-210: 6897
Bi-210: 6833
Po-210: 5407
Pb-206: stable

Pu-239: 51645 KeV
U-235: 46401
Th-231: 41723
Pa-231: 41332
Ac-227: 36182
Th-227: 36135
Ra-223: 29988
Rn-219: 24009
Po-215: 17063
Pb-211: 9536
Bi-211: 8169
Tl-207: 1418
Pb-207: stable

I think it's quite interesting that the decay for U-238 is about 1/4 of the energy released by fissioning that same nucleus, and that's what I was looking for when I arrived here. Iain McClatchie (talk) 09:11, 29 January 2009 (UTC)

You could also compute the energy released by fission vs. decay via the mass deficit between the original nucleus and the products in each case. You can even read a rough estimate of the energy release ratio directly off the curve of binding energy: --JWB (talk) 14:41, 29 January 2009 (UTC)

Thorium series

The end product of Thorium series id is given as Pb-208. The final product of neptunium series is refined to Tl-205. Pb-208 is also radioactive with a half life (>2E+19 a]) which is just comparable with that of Bi-209 (1.9E+19 a). So the end product should be refined. The radioactivity bad name is given only to bismuth and not to lead-204, lead-208 or even tungsten whose all isotopes are radioactive.Anoop.m (talk) 05:53, 24 January 2010 (UTC)

There doesn't seem to be any sources for this information. [IAEA] and [BNL] list Pb-208 as stable. BatesIsBack (talk) 15:24, 15 May 2011 (UTC)

In the picture of the thorium series the half-life of actinium-228 seems to have the wrong unit, it should be hours, not minutes. In the table the units are correct. (http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=890228) AquamarineOnion (talk) 06:05, 30 July 2012 (UTC)

Confused by a diagram caption

In the Actinium series section, a diagram is captioned: This image gives the detailed routes of actinium-237 decay.
However, the article Isotopes_of_actinium does not list actinium with a mass number greater than 236. Also, the image itself shows no such actinium-237. Was it supposed to say uranium-235? Nicknicknickandnick (talk) 07:04, 27 May 2010 (UTC)

There are isotopes of elements like actinium that are so rare (have such short half-lives) that they are not worth mentioning in an article about the element. In other words, the article on isotopes of actinium justifiably focuses in the more-common isotopes and omits the rare ones.
For example uranium-239 exists, BUT whenever any is produced (usually in a nuclear reactor, or by a collision with a stray neutron), U-239 nearly-immediately emits a beta particle and becomes neptunium-239.
Likewise, whenever U-235 absorbs a neutron, it becomes U-236 for about a nanosecond, but that U-236 nucleus breaks "in half" in the process or nuclear fission.
Nearly anytime you see a listing for an isotope like Ac-236, then one higher (Ac-237) or one lower (Ac-235) usually exists, but it would be extremely rare. 05:22, 4 June 2010 (UTC) —Preceding unsigned comment added by 98.67.167.211 (talk)

OK, but still why is the diagram captioned with regard to actinium-237 which is nowhere to be seen on the diagram or article? Nicknicknickandnick (talk) 08:01, 11 June 2010 (UTC)

Diagram missing an arrow

The diagram in the Radium series (also known as Uranium series) section is missing an arrow connecting up from the Po to the At. Nicknicknickandnick (talk) 07:10, 27 May 2010 (UTC)

This has been fixed in the SVG version of the image. BatesIsBack (talk) 15:24, 15 May 2011 (UTC)

Diagram containing mass number error

The diagram in the Neptunium series section has an isotope labelled on the exterior as Actinium 233 but should instead be labelled Actinium 225. Nicknicknickandnick (talk) 08:07, 11 June 2010 (UTC)

This has been fixed in the SVG version of the image. BatesIsBack (talk) 15:24, 15 May 2011 (UTC)

Page histories for substituted templates

The templates {{Neptunium series}} and {{Thorium series}} were substituted into this article and subsequently deleted. The page histories of those templates are provided below to ensure proper attribution of this material.

Extended content

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Radium series

I think the half life of Protactinium-233 is the same of Protactinium-234 in the two diagrams. The one for Protactinium-234 is wrong.--Stone (talk) 10:34, 25 December 2010 (UTC)

"This diagram illustrates the four decay chains"?

The caption on the first diagram in the article states "This diagram illustrates the four decay chains". Using "the" implies that there are only four decay chains. I find this hard to believe, and the article also states otherwise ("There are many shorter chains...").

So, are these the four "main" decay chains? The four "longest" chains? The four "most common"? (Someone with expertise should put the proper modifier in the caption, and add a corresponding sentence or two to the article.) -- Dan Griscom (talk) 12:08, 1 May 2011 (UTC)

The four important chains discussed in the section text. Clarified caption to indicate that. Vsmith (talk) 14:19, 1 May 2011 (UTC)

These would be THE four chains that reduce all isotopes heavier than lead to stability.

These are the four possible transuranic decay chains. Not that all their members are transuranic, but all transuranics fall into one of these four chains. SkoreKeep (talk) 04:25, 17 February 2014 (UTC)

U238 decay chain

WRONG HALF LIFE The half life of Pa234 is 6.7 h and NOT 27 d as indicated on the corresponding graph — Preceding unsigned comment added by 77.49.98.185 (talk) 07:18, 8 June 2012 (UTC)

Gadolinium-152 decay chain

In natural also have a decay chain begins with Gadolinium-152 which undergone triple alpha decay to form stable nuclide Cerium-140 (this nuclide contains 58 protons (semi-magic number) and 82 neutrons (magic number) thus exceptionally stable and can't decay further exempt for spontaneous fission). Atomic mass He-4 4.002602u, Gd-152 151.919791u, Sm-148 147.914823u, Nd-144 143.910087u, Ce-140 139.905439u Gd-152 => Sm-148 released 2.2MeV Sm-148 => Nd-144 released 1.97MeV Nd-144 => Ce-140 released 1.91MeVCristiano Toàn (talk) 09:06, 4 December 2012 (UTC)

Yes, but the problem is that ¹⁵²Gd, ¹⁴⁸Sm, and ¹⁴⁴Nd all have half-lives longer than the age of the universe, so every step is a bottleneck in the decay chain and so it happens really slowly. It's not as though the intermediate products would not exist but for a long-lived rate-limiting isotope higher in the chain, which is what happens with the chains from ²³²Th, ²³⁵U, and ²³⁸U. Double sharp (talk) 14:32, 3 September 2014 (UTC)

Gender specific nomenclature, institutionalized sexism

Why is the decay product called 'daughter' instead of the gender neutral 'child'? surely atoms do not have a social gender or a vagina. 71.82.220.226 (talk) 17:31, 4 October 2013 (UTC)

if this is due to the decay product potentially decaying and giving birth to another 'child' then is the final stable isotope called a son(one who does not directly give birth)? — Preceding unsigned comment added by 71.82.220.226 (talk) 17:35, 4 October 2013 (UTC)

There is not a final stable isotope beyond Nickel-62 and Iron-56 (which is considered nuclear 'ash' not 'son'). I feel the term 'daughter' adds respect and acknowledgement to the feminine. Atoms do not have vaginas, but they do spawn new, typically more stable, generations. I think identity politics should be kept out of the natural sciences. The atom isn't asking to be called anything in our language. 2001:569:BE91:F500:E978:E8DE:434E:19D8 (talk) 20:18, 25 February 2021 (UTC)

I honestly never thought about this! (But if you feel that the term is sexist, you can use "decay product", which is probably fine.) As for your final question, in general after granddaughters this terminology stops actually getting used, and the final product seems to be mostly called just that: "final (decay) product". Your rationale is probably the reason, though. (These final products are theoretically predicted to decay anyway, even though the decay hasn't been seen yet, so I suppose "son" would be overly restrictive here. ) Double sharp (talk) 04:34, 5 October 2013 (UTC)

Tradition. Like ships. SkoreKeep (talk) 04:22, 17 February 2014 (UTC)

References

Percentage of remaining decaying isotope

If the half-life of an isotope is 100 million years, then the amount left after 4.5 billion years is 2^-45 of the original amount, or 2.8e-14. That's 0.000000000000028 of the original, or 0.0000000000028%. SkoreKeep (talk) 00:09, 21 February 2014 (UTC)

Meaning of "more tolerant of a high n/p ratio"

I am repeatedly reverting an edit by User:SkoreKeep. Here is the rationale.

Along a family of isobars, there is generally an optimal n/p ratio that yields the lowest energy and thus the higher stability. The nuclide energy tends to increase as we move further from this optimum. Since alpha decay products tend to be born with a higher than optimum n/p ratio, some of them beta-decay into nuclides of lower n/p ratio and hence lower energy. This is the point of the beta-decay: to decrease energy by lowering the n/p ratio. It's not about "being more tolerant" to a high n/p ratio.

I tried to make sense of the sentence anyway. What would it mean to say "nuclide A is more tolerant of a high n/p ratio than nuclide B"? If nuclide A has an n/p ratio that is higher or equal than that of nuclide B, and yet A is more stable than B, then A is indeed more tolerant of a high n/p ratio. However, is the more stable of these nuclides has a lower n/p ratio, then it makes no sense to say it is more tolerant of a high n/p ratio. — Edgar.bonet (talk) 09:43, 26 February 2014 (UTC)

OK, I'll take a look at it again tomorrow, and see what I've done wrong, and try to get it correct, and a little less loosely worded.

What exactly does it mean to have "repeatedly reverted" my edit? As far as I can see, it makes sense to revert it if it is egregiously wrong (which it sounds like it may be), but you didn't revert at all, just changed the wording. SkoreKeep (talk) 11:15, 26 February 2014 (UTC)

I mean I changed the wording twice, both times in more or less the same way ("more tolerant of a high n/p ratio" → "with a lower n/p ratio"). I cannot say it's egregiously wrong: for me it's more like a confusing wording I cannot make proper sense of. — Edgar.bonet (talk) 08:44, 28 February 2014 (UTC)

Original research?

This article lacks any inline citations and reads like original work. 173.243.179.223 (talk) 14:34, 25 February 2017 (UTC)

(Moved from the top of the talk page.) I agree that the lack of citations is a problem, but it is most definitely not original research: all of these decay chains were known from the early history of the discovery of radioactivity, even if of course some of the isotopes in them remained to be discovered later (for example, the isotope with ²²⁷Ac as its daughter was looked for by many until it was finally found by Hahn and Meitner in 1918). It is very easy to find sources listing these decay chains online simply by searching those names; they are all mentioned in Greenwood and Earnshaw (chapter 31 is on the actinides and includes these). Double sharp (talk) 15:49, 25 February 2017 (UTC)

Agree. This data was known before some of the decaying elements were officially discovered and named themselves. SkoreKeep (talk) 21:43, 15 June 2017 (UTC)

Yet more diagrams

I have a set of paper diagrams with the mass number as the y axis and the atomic number as the x axis. These seem very clear, even if not as pretty as the ones we have.

I was wondering if it would be possible to put all four series on the same diagram using different colours for them.

All the best: Rich Farmbrough, 19:46, 15 June 2017 (UTC).

I don't know what is the meaning of the different colors in the four decay chains, or why the uranium chain has hexagons rather than spheres. I suppose that we'd have to see what your combined diagram looks like. Would it be possible for a person to print out the combined diagram and then cut them apart, if that is their preference. Easier than printing four diagrams and pasting them together? TomS TDotO (talk) 20:33, 15 June 2017 (UTC)

It's apparent that the diagrams were done by at least two different people. The color codes seem to be indicating classes of elements (halogens, etc) but they aren't consistent. By all means bring in a different set of diagrams; if you need help I'm sure there are artistic resources to make correct diagrams as pretty as anyone could desire them. As for combining them, I'd personally rather see each diagram matched with its text as it is now; I don't see a point in being parsimonious with page space, since there seems to be a lot available. Also the vertical arrangement of the existing charts works with that. Not being a chemist I'm not into the color scheme being used; there has to be a better use of the information space, I think. My 2 cents. SkoreKeep (talk) 21:39, 15 June 2017 (UTC)

This is the sort of thing I had in mind except with transposed axis: of course someone has already thought of it. I was also considering line thickness as 1/(log₁₀₀₀ half-life). All the best: Rich Farmbrough, 12:03, 19 June 2017 (UTC).

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Radium/Uranium chain

Alone of the four tables the Radium table is called by a macro "uranium/radium chain" and woe is me, I don't know how (more likely where) to edit such a thing. Perhaps all I need is a spot of assistance here? Is there any need to have broken out the table into a separate file for just this one? I'm just an engineer; I don't know any better.

The reason it needs editing (as far as I would like) is that it is inconsistent with the other tables. Instead of grouping together different decay modes of a single parent in a single table row, it has separated them out into separate table rows. Yeah, I know, consistency is the hobgoblin..., but is there some reason it should be that way? I also notice that at least one low-probability chain is just dropped: the Pa-234 result of decay from Pa-234m. My presumption is that if you mention it, then it's best to follow through.

One last change I'd make is getting rid of the Subtotal MeV column. The total is mentioned in the text, and adding it up as we go seems oddly unuseful. I'd also combine the decay mode and probability in a single column - consistency again. The table is a lot wider than the others because of these. SkoreKeep (talk) 23:48, 29 June 2019 (UTC)

The table is at {{Radium series/table}} – I suspect because our article on uranium-238 uses it too. BTW, ²³⁴Pa (UZ) is there, but it immediately beta decays to ²³⁴U and rejoins the main chain. I agree with what you say; and I also think that if we want consistency, we should also start the chain off with ²⁵⁰Cf, ²⁴⁶Cm, and ²⁴²Pu, since we start the other chains off with ²⁴⁹Cf, ²⁵¹Cf, and ²⁵²Cf. Double sharp (talk) 03:09, 30 June 2019 (UTC)

After considering it a bit, I've decided to create a new table in the decay chain article so that the source code matches with that of the other three tables, as well as adjusting the columns and rows as I discussed. It appears that each of the tables (or at least three of them) were once bound as the radium series table is now, but were eventually made distinct. Oh, and thanks for the information, Double sharp, I learn something new every day. SkoreKeep (talk) 06:12, 30 June 2019 (UTC)

Did it. Please cross-check for any errors. Will look up values for additional rows at top of table tomorrow. SkoreKeep (talk) 08:11, 30 June 2019 (UTC)

I added three more rows at the top for ²⁵⁰Cf, ²⁴⁶Cm, and ²⁴²Pu, with data from Theodore Gray's website. Double sharp (talk) 15:51, 30 June 2019 (UTC)

gamma?

I'm no expert, is there a reason why gamma emissions aren't mentioned anywhere? Is there any material on how much gamma radiation is emitted at any given decay step in a chain? 190.100.175.35 (talk) 07:34, 4 August 2020 (UTC)

Gamma emissions are not mentioned anywhere because they do not result in the conversion of one nuclide to a different nuclide, only the release of excitation energy. This contrasts with alpha and beta decay, which respectively convert (Z, N) into (Z − 2, N − 2) or (Z + 1, N − 1). As such, there is no change to reflect in the table. ComplexRational (talk) 15:43, 4 August 2020 (UTC)

Yes, I understand that, but why is that a valid reason not to include them? It would seem to me gamma emissions are a large part of the reaction and can have serious consequences, why is that not enough for their inclusion? 190.100.175.35 (talk) 16:05, 4 August 2020 (UTC)

If this has been discussed and sufficiently answered before I would gladly be pointed to said discussion. No desire to beat a dead horse. But I would like to know if there's a way for me to find out how much gamma, if any, is emitted at each step. 190.100.175.35 (talk) 16:10, 4 August 2020 (UTC)

"safe" decay chains

This is related to the last question. Its just curiosity, but isn't something I can answer from the article.

Suppose you were to create a museum of the elements, with a sample of each (practical) element in a display case, and were able to synthesize kg quantities of any long-lived isotope you liked. Alpha decay would be acceptable because the glass of t:{he case would be enough to block the radiation. Which radioactive elements would be safe to display to the public, assuming we ventilated to eliminate radon?

For example, Tc-97 and Tc-98 both have 4My half-lives and decay to stable isotopes, so there are no radioactive products to worry about. But one decays by beta or gamma-emission, both of which would irradiate the audience, and the other by electron-capture, which also produces gamma rays. Unless the amount of radiation from a kg chunk of Tc was not much about background, Tc would not be a safe element to display.

Pu-238 famously can power a spacecraft, but a piece of paper will block its radiation. It would be really cool to have a red-hot kg of Pu-238 in a display case, where people could feel the heat radiating through the glass (and heating the glass). But what of gamma radiation from its decay products? What dosage would we be looking at, and how much would that increase after leaving it on display for a decade or two? Pu-244 wouldn't be as spectacular, but would presumably be safer. Would it be possible to have a kg of the most stable isotope of thorium, uranium or plutonium on display in a glass case, since they all alpha-decay? Would any others be possible? — kwami (talk) 09:31, 15 September 2020 (UTC)

@Kwamikagami: Interesting question. The difficulty for most of the more radioactive elements is really self-heating from the radioactive decay: already a gram of pure radium is problematic. So I think you might not be able to get that many radioactive elements displayed in significant quantities even if we didn't consider the safety. Double sharp (talk) 10:06, 15 September 2020 (UTC)

I wasn't sure radium would be possible. Thought I'd see if the more stable isotopes would be possible first.

Yes, the Pu-238 fuel pellets in spacecraft are the oxide, but Pu-244 has a much much longer half life than radium. But even if pure metal Pu-244 reached its melting point of 640C, there's no reason the kg on display couldn't be liquid.

Pu-242 only generates 0.1 W/kg, and 244 should be less, but our article doesn't include it in the table, so perhaps it's too difficult to synthesize. — kwami (talk) 10:25, 15 September 2020 (UTC)

@Kwamikagami: That's right, Pu-244 is hard to synthesise because Pu-243 has a too short half-life, so you cannot get to it by slow neutron captures. It can be made via nuclear explosion, or by going up to Cm-248 by slow neutron capture and waiting for the alpha decay, but doing it the latter way means lower yield. My worry was not just about liquefying the sample, but also where it's contained (because that's surely going to heat up).

Most stable isotope half-lives go basically Bi (1E19 y) >> Th, U (1E10 y) > Pu (1E8 y) > Cm, Tc (1E7 y) > Np (1E6 y) > Pa (1E5 y) > Am (1E4 y) > Ra, Bk, Cf (1E3 y) > Po (1E2 y) > Ac, Pm (1E1 y) > Es, Fm (1E0 y), rounding to the nearest power of ten logarithmically, FWIW. If Pu-242 is OK, then it seems to me that heating concerns should allow everything up to Np on that list. The worry would then be from gamma, but I suppose you could display it with leaded glass. But I am certainly no expert on radioactive safety, just an interested amateur who has never even seen uranium in person. XD Double sharp (talk) 11:16, 15 September 2020 (UTC)

Leaded glass wouldn't be enough, would it? The electrons would hit the glass and I would think the gamma rays from their deceleration would go right through. If leaded glass is enough, then I would think most long-halflife isotopes would be displayable. — kwami (talk) 11:37, 15 September 2020 (UTC)

Any mass attenuates gamma rays. Dry air will attenuate them at the rate of 1/2 their intensity for 200 meters (600 feet), or by a factor of about 256 per kilometer, about 1000 per mile. That is why people could watch an atomic test at six miles range with no radiation effects. So for leaded glass (or unleaded glass or water or anything else), it's just a question of getting enough in place between you and the source to reduce the gamma rays to acceptable levels. The worst possible source of radiation, fresh spent fuel rods, can be stored in a water pool with 2 meters of water between the rods and people working in a shirt-sleave environment.

Gamma rays do not decelerate - they are a form of EM radiation, like light, and travel at the speed of light in the medium they are in always. SkoreKeep (talk) 16:50, 15 September 2020 (UTC)

I meant gamma radiation from when the electrons decelerate. (Or from traveling faster than the speed of light in their medium.) That's why something that will absorb electrons may not be enough shielding for beta radiation.

Is the factor of 256 per km in addition to the square-distance attenuation of an omnidirectional source?

Still, I'm curious about how much shielding would be needed for the various long-lived isotopes. — kwami (talk) 23:59, 15 September 2020 (UTC)

No, the inverse-square effect is not part of the shielding effect; it is in addition to it. The factor of 256 per km does not include it. I don't know what bremmstrahling will add to the gamma radiation from decay, but it will still have to pass through the glass and likewise be attenuated. SkoreKeep (talk) 14:15, 16 September 2020 (UTC)

So I guess my question is, where do I go to find out how much glass (or what kind of glass) is required to shield a strong beta emitter, so it can be safely observed? — kwami (talk) 23:10, 17 September 2020 (UTC)

Error in data

210-Po is written as decaying via alpha decay into 206-Tl instead of 206-Pb, but this would require an alpha particle of 3 protons, would it not! I wonder if there are other such errors in the data. --RProgrammer (talk) 23:52, 23 October 2020 (UTC)

@RProgrammer: You're right, it's an error. Corrected; thank you! Double sharp (talk) 23:54, 23 October 2020 (UTC)

Would "nuclide" be more appropriate than "isotope" in this article?

https://en.wikipedia.org/wiki/Nuclide says, "Since isotope is the older term, it is better known than nuclide, and is still occasionally used in contexts in which nuclide might be more appropriate, such as nuclear technology and nuclear medicine." and "Although the words nuclide and isotope are often used interchangeably, being isotopes is actually only one relation between nuclides. The following table names some other relations." and "A set of nuclides with equal proton number (atomic number), i.e., of the same chemical element but different neutron numbers, are called isotopes of the element. Particular nuclides are still often loosely called "isotopes", but the term "nuclide" is the correct one in general (i.e., when Z is not fixed). In similar manner, a set of nuclides with equal mass number A, but different atomic number, are called isobars (isobar = equal in weight), and isotones are nuclides of equal neutron number but different proton numbers. Likewise, nuclides with the same neutron excess (N − Z) are called isodiaphers. The name isotone was derived from the name isotope to emphasize that in the first group of nuclides it is the number of neutrons (n) that is constant, whereas in the second the number of protons (p)." Polar Apposite (talk) 16:54, 14 July 2023 (UTC)

Dottedness of arrows too hard to see in the actinium series diagram.

It's very hard to see that the arrows indicating alpha decay of francium-223, beta decay of polonium-215, and beta decay of bismuth-211 are not solid but dotted, in the diagram of the actinium series. This seems to be because the arrows in the diagram are rather narrow, unlike those in the diagram of the uranium series, which are wide, and thus allow the dotted lines to be easily distinguished from the solid ones. It is also hard to see that there are two kinds of dotting, big and small, or, if you prefer, dotted and dashed. So I think it would be great if someone who knows how to edit the actinium series diagram would thicken the arrows. Polar Apposite (talk) 14:48, 20 July 2023 (UTC)

Need for both dotted and dashed arrows.

I don't see why there are two both dotted and dashed arrows in the actinium series diagram. It seems to me that the dashed arrow could be replaced with a dotted one. Also, the dashed arrow representing the beta decay of bismuth-211 is very unclear, and looks like it could me a misprint. Polar Apposite (talk) 18:48, 20 July 2023 (UTC)