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Perhaps this page can be folded into the Radioactivity page? It seems a bit redundant having both...
Both are usefull, this one on the mechanisms and pyhsics, the other one for the seconadry effects of decay, on environment, bioloy etc.
Btw. does anyone know if there exists a formula by which, given the number of protons and neutrons, the half-life of a nucleus can be derived?
The above argument for maintaining separate articles here and at Radioactivity is no longer valid. We need to decide which article will be kept, and which will be made into a redirect. The case as I see it is thus:
-- Smack 06:26, 23 Nov 2004 (UTC)
Please add any new arguments to this list. -- Smack 22:09, 14 Nov 2004 (UTC)
I can see no problem with keeping both. Wikipedia is not written on paper and data can be held several times over in different places with minimal extra cost. The principal search term will probably be Radioactivity but a more detailed look at Radioactive decay, perhaps detailing the rate of decay of specific elements and isotopes would be very interesting and would be too much detail to hold on the Radioactivity article. Lumos3 09:43, 23 Nov 2004 (UTC)
Let's have another vote. Should this article live here, or at Nuclear decay? The present title is favored by a Google test, seven to one. -- Smack ( talk) 23:56, 24 Mar 2005 (UTC)
What determines which type of radioactive decay will happen? Thanks. -- Eleassar777 12:09, 30 May 2005 (UTC)
Are there any (simple) equations that roughly describe this? How do these factors interact? Thanks. -- Eleassar777 08:38, 31 May 2005 (UTC)
One rare decay process that is not mentioned anywhere is the emission of a carbon-14 nucleus. I think it's like spontaneous fission, but acts like alpha decay in that the nucleus that is emitted always has the same mass number (14).
Some isotopes of radium can decay by this method, such as Ra-221, Ra-222, Ra-223, Ra-224 and Ra-226.
Reference: Isotopes of Radium -- B.d.mills ( Talk) 03:13, 15 Jun 2005 (UTC)
Double electron capture is so rare most sources don't even say that it exists. My chart of the nuclides doesn't list it as a decay method, neither does environmentalchemistry.com. I have not heard of it other than here and will ask my professors when I get back to university. However, your quoted source does but it also lists the following types of emissions too:
-- metta, The Sunborn 15:05, 22 Jun 2005 (UTC)
No, it doesn't. -- Smack ( talk) 04:44, 18 September 2005 (UTC)
So does anyone want to fix the cadmium article? Ken Arromdee 21:20, 23 September 2005 (UTC)
I tried fixing it myself. However, the two sources above contradict. One says >1.2E21 years and the other says 3.1E19 years. Which is correct? Ken Arromdee 18:20, 19 October 2005 (UTC)
what type of radioactivity produces only energy waves
Is this the right page for clarifying the bewildering variety of measurements associated with radioactivity, or has this been done elsewhere? Joffan 01:13, 31 October 2005 (UTC)
How common is radioactive decay? Which materials exhibit radioactive decay and why? Where am I likely to encounter them? Rtdrury 05:12, 2 January 2006 (UTC)
BlueEVIL420 66.20.103.36 16:36, 24 February 2007 (UTC)
(template removed - request rejected. Vsmith 04:40, 24 March 2006 (UTC)
I am sure all of do not agree on the existence of true randomness.....I for one, do not belive it exists.....evrything is caused by something and also reacts in some way. An atom will not start behaving in a manner that is not triggered by something else. In case of radioactive decay, I am sure you all agree that we do not yet completley understand all the sub-atomic forces working, and their consequences.....so just because we do not know why, it is wrong to assume that something is truly random. In this article, there are several uses of the word random used in a sense implying that true randomness does exist. 'On the premise that radioactive decay is truly random...' etc... I simply wish to change the languge used throughout the article to eliminate this sense, but thought I should bring it out on the discussion board first. Again, my intention is only to slightly modify the language in those parts on the article, not to change or challenege any other factual information provided.
According to the article on randomness on wikipedia.... "The word random is used to express APPARENT lack of purpose, cause, or order." Hence true randomness seems to me as an oxy-moron.
Abhishekbh 04:23, 24 March 2006 (UTC)
I happen to think this simply introduces an unnecessary assumption, without reason, and should be rejected following Occum's razor. But in any case, I see no reason a priori to reject the very idea of causeless events. If you can't see the cause, you have no good reason to demand that something you can't find or point to, still exists.
And besides, if you reject causeless events, you are left with strict determinism, by excluded middle argument. Are you happy with determinism? I guess you must be <grin>. You have to be <grin>. S B H arris 23:02, 24 February 2007 (UTC)
I keep seeing the trefoil upside down in certain publications... is that wrong, or are both directions acceptable?
The measurements of activity I've seen are Bq/gram. I don't know how simple Bq would mean anything significant. In any case, I think its an important relation to have: the relation between half-life and decays/gram/second. Fresheneesz 18:58, 31 May 2006 (UTC)
Stimulus not a term usually found in context of radioactivity descriptions and is not found in the reference given. What are its meaning and its relevance for the article?
...predictions using these constants may be less accurate if the substances are in situtations that provide extra stimulus. [2]
Jclerman 13:06, 20 June 2006 (UTC)
The radiometric decay rates used in dating are totally reliable. They are one of the safest bets in all of science.
Nuclides are not nuclei. They have been edited. Jclerman 02:08, 24 June 2006 (UTC)
Modes of Decay has been merged into this page SuperTycoon 16:42, 15 July 2006 (UTC)
A recent edit
The summary for this edit to the "Decay chains and multiple modes" section asks "Is this really true? A given uranium isotope always ends in the same lead isotope, no?". I can't find a reference for uranium having multiple decay modes, but some isotopes of some elements do have multiple decay modes. The section also mentions 212Bi, which is a valid example according to the Decay chain article, so I edited the text to remove mention of uranium. The second part of the summary contains the hidden assumtion that a different decay mode early in a decay chain (or a "branch" to continue the chain analogy) will result in a different stable endpoint. This is not true; according to the Decay chain article, the two decay chains for 212Bi reconverge at 207Pb. DMacks 20:26, 31 July 2006 (UTC)
Is there a theory about what causes the randomness of decay? I mean why should some atoms go off immediately, and others wait, perhaps, millions of years?-- Light current 22:43, 25 September 2006 (UTC)
I think this article should have its own section describing the dangers of radioactivity. Now, it's included in the end of the "Discovery"-section as a historical note only. Kricke 01:27, 17 February 2007 (UTC)
.(Note from curious passerbyer, when it says "all but vanished," doesn't that mean it didnt vanish from the market? I mean it translates to me as anything happened but vanishing from the market. I might be wrong but didn't radioactive treatments vanish from the market? (Touche, my friend. I find your logic rather sensible.))
Are all matter radioactive? They say that only unstable atoms are radioactive, and that through radioactivity it eventually becomes stable again. So is it then no longer radioactive? Will the world one day be completely stable when everything has become stable? Or...? ► Adriaan90 ( Talk ♥ Contribs ) ♪♫ 18:35, 29 June 2007 (UTC)
I think a graph showing an exponential decline curve would be useful in this article. —Preceding unsigned comment added by 212.219.123.32 ( talk) 12:03, 4 October 2007 (UTC)
I know of the existence of a type of decay called negatron emission, however I do not see it listed on this page. Perhaps someone should add it. Nschoem 01:03, 21 February 2008 (UTC)
It has been discovered that nuclear deacy vares over time, or more accurately: with the Earth's distance from the sun. Can someone make a section of this please?
http://science.slashdot.org/science/08/08/29/1227239.shtml -- J-Star ( talk) 23:31, 29 August 2008 (UTC)
Q.: Shouldn't relativity be applied to the integral transformation points of a decay series for a better description of the passage of time? ie thinking about the clocks experiment and our static location in spacetime when an observation is made; the assumption of linear temporal decay from thenthere to herenow must be innacurate? (not only given a differential for time passed but also vector location changes as the earth spins etc). DGreenhill 151209 —Preceding unsigned comment added by 82.111.134.82 ( talk) 12:03, 15 December 2009 (UTC)
Is Radioactivity a physics or a chemistry related subject? —Preceding unsigned comment added by NoPity2 ( talk • contribs) 16:52, 14 October 2008 (UTC)
Originally, research on radioactivity was a branch of chemistry, because the first problem was to chemically isolate and identify the substance emitting the radiation. Nowadays I think things like "radio-chemistry" denotes the chemistry of compounds of radioactive elements, much as "organic chemistry" denotes the chemistry of compounds of carbon. For example, in medicine, you want to use compounds that can efficiently deliver the radioactive elements to the tissue to be radiated. Finding, making, and using such compounds is chemistry, not physics. WmMBoyce ( talk) 00:07, 29 September 2009 (UTC)
From Radioactivity:
From Marie Curie:
I feel that the introduction should acknowledge the monograph by Rutherford, Chadwick and Ellis first published 1930, latest edition 'Radiation from Radioactive Substances' Cambridge Univ.Press 1951 —Preceding unsigned comment added by Michael Nettleton ( talk • contribs) 15:19, 8 January 2010 (UTC)
PLEASE FIX THE SYMBOLS ---- They are showing as red error messages (could not parse.... etc) - scroll to bottom half of page. The section after the decay chains is riddled with them! 122.49.138.138, 13:27, 21 February 2009
I question the changes made to the intro paragraph on 20 May 2010 by Androstachys. First the word "spontaneously" was removed as "misleading" in the phrase "... an unstable atomic nucleus *spontaneously* loses energy by emitting ...". Why is this word misleading? Perhaps its meaning could be made clearer. I propose inserting the sentence "The emission is spontaneous in that the nucleus decays without collision with another particle."
In the same edit the word "currently" was inserted in the phrase "... it is currently impossible to predict when a given atom will decay ...", with a reference that does not justify the word "currently". I think a more accurate formulation would be "According to quantum mechanics, it is impossible to predict when a given atom will decay". This would clarify that not only do we currently have no theory to predict the decay of a given atom, but we also have a very general theory (accepted by the majority of physicists) which says that we can never predict the decay of a given atom.
I will wait a few days for comments before making these changes. Dirac66 ( talk) 16:27, 26 May 2010 (UTC)
The reference given for "according to quantum mechanics", however, does not mention quantum mechanics or how QM explains or predicts (no pun intended) that such a prediction is impossible. —Preceding unsigned comment added by 173.11.1.218 ( talk) 23:16, 24 November 2010 (UTC)
I'm not sure that the history section is correct. Pages like [3] [4] [5] [6] [7] [8] does point to that Abel Niepce de Saint-Victor might have discovered radioactivity before Becquerel. Reko ( talk) 18:15, 22 June 2010 (UTC)
Which types of atoms actually decay? There isn't even a summary in this Wiki article. I put a pretty good one in, and you removed it, because it's duplicated somewhere else. Okay, quick, people: without looking at Headbomb's edit summary, WHERE would you find such a thing? S B H arris 18:56, 13 September 2010 (UTC)
On the larger issue, whether a summary of the various types of atoms that are radioactive actually belongs in, or has "a place" in, the article on radioactive decay, is not for you to say-- it's a matter for consensus decision. Which I've now asked for, on the TALK page. As also, is the question of whether the mathematics of the solution of the first-order exponential differential equation has a place in this article, rather than the article that actually deals fully with the mathematics of this, which is exponential decay. Don't forget that much "sarcasm" is merely a serious logical suggestion that somebody doesn't like, because it exposes their biases. S B H arris 19:26, 13 September 2010 (UTC)
This discussion is becoming heated. May I suggest as a possible compromise that the article include a brief statement, that the summary of how many nuclides decay by each mode can be found in the article on Nuclide. This would make the information more accessible to interested readers of this article, while keeping the article from becoming unnecessarily long. Perhaps in the See also section, but with an explanatory comment describing the table, or else just prior to the See also section. Dirac66 ( talk) 00:59, 14 September 2010 (UTC)
It would be very nice for this article to indicate in some way, not only the different types of radiation, but also which types of radiation dangerous and what is considered a dangerous dosage level.
My understanding was that basically it's only Gamma radiation that can be extremely dangerous, but I'm not an expert.
Zuchinni one ( talk) 21:31, 17 October 2010 (UTC)
The "Danger of radioactive substances" section claims Marie Curie had a low exposure to radium and had been careful with it; but our Marie Curie article mentions that her papers and even cookbook are radioactive and dangerous to this day. Which is it? Comet Tuttle ( talk) 05:12, 3 November 2010 (UTC)
Could a knowledgeable editor add some content on the history of how the dangers of ionizing radiation were discovered? Comet Tuttle ( talk) 05:14, 3 November 2010 (UTC)
Re the following sentence added today by SBHarris: "The relationship of types of decays also began to be examined: for example it was found that beta decay almost invariably preceded gamma decay, and not the reverse."
Does this mean: 1) If a given nucleus emits a beta and a gamma, then the beta is emitted first? Or 2) If a given nucleus emits a gamma, then a beta is emitted first? Or 3) If a given nucleus emits a beta, then a gamma is emitted subsequently? Please clarify which is meant. Dirac66 ( talk) 21:35, 8 November 2010 (UTC)
We now have 3 red links for "bound state beta decay". Before anyone adds a new article on this subject, I would like to suggest that we instead add a new section to the existing article on beta decay. We can then point the links from this article to that section. Dirac66 ( talk) 00:56, 15 November 2010 (UTC)
There is no obvious mention that for the decay process A → B the equation
is the universal decay law for a nuclide A, nor is there the more generalized A → B → C
with solution
where specifically NA0 = initial number of nuclides of type A. All symbols with usual meanings. I will slightly tweak context for what it is, and try to add referances while at it.
Maschen ( talk) 22:07, 27 October 2011 (UTC)
Finished with my reformulation. You have a point Dirac66, - i'll add a link of analogy.
Furthermore I have a niggling feeling that people will complain about the overlap between parts of the exponential decay article and this one. For those that will: I don't care about arguments. For this article, the equations are explained in detail and in specific context of radioactivity, in that article there is not much explaination for the chain decay law as a differential equation itself - the whole point of what I just did is to outline the maths behind the law of radioactive decay...
Maschen ( talk) 18:00, 28 October 2011 (UTC)
how about a section on uses of radioactivity — Preceding unsigned comment added by 109.148.122.30 ( talk) 20:29, 17 December 2011 (UTC)
Section Explanation, second paragraph, last sentence: "The limits of these timescales are set by the sensitivity of instrumentation only, and there are no known natural limits to how brief or long a decay half life for radioactive decay of a radionuclide may be."
Actually the universe does have a speed limit of c, so that nuclear fragments cannot separate by a nuclear distance of 10-15m in a time shorter than 10-15m / c = 3 x 10-24 s. This is why there are several radionuclides with half-lives between 10-24 and 10-20 s, but none shorter. Except that the article now includes a value of 3 x 10-27 s for He-2, implying that the two protons separate 1000 times faster than the speed of light. This value is unsourced and I do not believe it, so I have marked it as Citation needed. See also my further comments at Talk:Isotopes of helium. Dirac66 ( talk) 14:58, 19 December 2011 (UTC)
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The introductory paragraph is entirely too detailed and much of the material therein needs to be moved to later paragraphs and trimmed out of the intro. — Preceding unsigned comment added by Zedshort ( talk • contribs) 20:38, 1 April 2012 (UTC)
>Actually, I have read the entire article and like most articles on wikipedia it is cluttered, poorly phrased and needs reorganizing, hence my attempts. I am sorry if I gave offense by adding the hypothetical process of positron capture but I find the potential of that process interesting and like to include it just for the sake of completeness. If there are more than five processes of radioactive decay I think they should all be added. Perhaps a table of those dozen or more methods would be the best format with all the products included. But from most of the sources I have read typically only three or five are listed. I wonder, have we had a dispute somewhere in the past as you seem to have taken offense at my being here and making these changes? I think I remember you adding to the article on the Energy-Catalyzer. Sincerely — Preceding unsigned comment added by Zedshort ( talk • contribs) 00:40, 2 April 2012 (UTC)
Hi,
the general solution to the recursive problem by Bateman's equations does not seem to be correct. The correct equation is shown at http://www.physicsforums.com/showthread.php?t=452474
may be someone can change this, with best wishes Wolfgang — Preceding unsigned comment added by 212.95.7.181 ( talk) 12:58, 12 April 2012 (UTC)
Hello all. The formula for Bateman's equations given in the physics forum link above and now on the wikipedia page does not agree with that given in Kenneth S Krane's Introductory Nuclear Physics (Unit II Nuclear Decay and Radioactivity, Chapter 6 Radioactive Decay, Page 173 in my copy). Krane doesn't have the decay constant after the sum term in the Nd formula. If someone could confirm and change I'd be much obliged. [This comment by 86.177.136.35, 24 June 2012]
For example, the article on Cadmium states that: "The two natural radioactive isotopes are 113Cd (beta decay, half-life is 7.7 × 10^15 years) and 116Cd (two-neutrino double beta decay, half-life is 2.9 × 10^19 years)." How is such an extraordinarily long decay rate calculated/predicted? 124.184.13.246 ( talk) 09:01, 31 August 2012 (UTC)
Try asking the reference desk. Wikipedia:Reference desk/Science -- Klausok ( talk) 11:20, 31 August 2012 (UTC)
Look for 'isomeric' instead of 'isometric' and if doing this myself is not illegal please reply telling me that i should have done then and there Khpatil ( talk) 14:54, 7 December 2012 (UTC)
Quote: "Primordial nuclides found in the earth are residues from ancient supernova explosions which occurred before the formation of the solar system."
EVIDENCE for this? ANY? EVIDENCE? AT ALL? — Preceding unsigned comment added by 78.156.126.230 ( talk) 15:36, 20 December 2012 (UTC)
As to the more interesting question of where heavier-than-iron nuclides come from, it's complicated. About half of the nuclei heavier than iron are s-process nuclei that required some slow cooking somewhere (like AGB stars where free neutrons come from alpha reactions on C-13 and Ne-22) and the rest are r-process nuclides that require a truly titantic neutron flux from some fusion bomb event (like the first H-bombs making Es and Cf out of U and Pu). The sites for this are probably high mass supernovae that aren't quite large enough to make black holes, but have as many free neutrons at the end as possible. Certainly U and Th were made that way, and I'll have to go through the tables to see about the other 30-odd primordial radioactives. Some may be s-process nuclides that haven't been (or at least were not REQUIRED to have been) put through a genuine supernova or even nova, so we'd be liars if we said that all such nuclides heavier than iron had. Apparently red giants make some really heavy nuclides by the s-process, dreging them up and saute-ing them, then eventually puffing them gently out into space to make later generation solar systems like ours. S B H arris 06:02, 21 December 2012 (UTC)
The article says:
"[...] Although the parent decay distribution follows an exponential, observations of decay times will be limited by a finite integer number of N atoms and follow Poisson statistics as a consequence of the random nature of the process. [...]"
I'm pretty sure that the exact distribution is not Poisson's; it is Binomial with parameters and . I have done the math derivation myself.
I added the "citation needed" template as a warning for readers.
GNU/Octave code to simulate problem: http://pastebin.com/UHsrfXu0 (comments in Spanish)
Generated image: http://postimg.org/image/dqe92tzkn/
(In the background you can see a 3D plot (with color) of the Binomial probability function (of N(t)) evolving with time)
— Preceding
unsigned comment added by
Francisco Albani (
talk •
contribs) 08:02, 19 June 2013 (UTC)
From the article:
I don't think having incorrect equations in an article is a good idea: when people are looking for the formula, they won't pay much attention to the text, and even when they know the last one is wrong, they may accidentally copy it (easy mistake to make: you look up from your paper, see a line that begins with what you just wrote, so you assume that's the one you were copying). I doubt that people who know differential equations would need to be told explicitly why the two terms don't have the same sign, and you certainly don't need an incorrect formula to explain the correct one. Ssscienccce ( talk) 19:14, 20 January 2014 (UTC)
This text, which appears under the "Discovery and History" heading, should be moved to the "Occurrence and applications" section:
That is, assuming it belongs in the article at all. There are numerous applications of radioactivity that are not listed anywhere in this article; Food irradiation, cancer treatment, tracing underground pipes, labeling chemicals for biological experiments, smoke detectors, radio-thermal generators,... That's just scratching the surface. There's no scientific reason why dating rocks and fossils is any more special than any of those. 129.42.208.183 ( talk) 23:10, 30 January 2014 (UTC)
You are welcome. Zedshort ( talk) 01:37, 30 September 2014 (UTC)
Otto Reifenschweiler also observed changes in decay rates in Tritium Reduced radioactivity of tritium in small titanium particles (published in Physics Letters A.)
Claus Rolfs has performed experiments in which he accelerated radioactive decay Half-life heresy: Accelerating radioactive decay
Should these two also be mentioned in the section ? -- POVbrigand ( talk) 14:13, 7 May 2012 (UTC)
Looking to the 3 figures on the reference nr. 29, "Evidence against correlations..." one has to conclude that their claim is not substantiated because a synchronous variation will not show on the graphs. On what basis they assume very unlikely ? quoting: "If the Jenkins proposal were correct, it is very unlikely that the alpha, beta-minus, beta-plus, and electron-capture decays of all radioactive isotopes would be affected in quantitatively the same way. Thus the ratios of counts observed from two different isotopes would also be expected to show annual variations."
79.168.86.244 ( talk) 18:14, 10 May 2015 (UTC)
This article just links to a few items on wikidata, I don't know why. Please make attention.-- 171.232.148.168 ( talk) 15:09, 15 June 2015 (UTC)
"Although these are constants, they are associated with statistically random behaviour of populations of atoms. In consequence, predictions using these constants are less accurate for small number of atoms."
I changed this to be somewhat *less* misleading (current edit):
"Although these are constants, they are associated with the statistical behavior of populations of atoms. In consequence, predictions using these constants are less accurate for individual atoms."
- Because deleting it yielded a reversion from another user. The original statement was patently misleading. The problem with small numbers of atoms is not with constants or statistical behavior, but rather with analytical techniques. Except in a few cases where half lives are too long to be very well constrained. So...it really is wrong/misleading. My best guess is that it was put in by a creationist type to cast doubt on the veracity of radioisotopic dating. Geochem. PhD here. I apologize if the format of this talk page edit is not perfect; I do not edit wikipedia with any regularity. Saw this error while perusing the page. Can someone with more clout on here delete the phrase and keep it that way? — Preceding unsigned comment added by Meteoritekid ( talk • contribs) 09:21, 12 June 2015 (UTC)
The last part of the "half-life" subsection contains a bit of LaTeX {{math|''t'' = ''T''{{sub|1/''n''}}}} that comes out nonsense (as {{{1}}} on all my browsers), and which needs to be fixed. But I don't see anything obviously wrong with it. Can somebody figure out what the second expression needs to be?
Here it is:
Mathematically, the nth life for the above situation would be found in the same way as above—by setting N = N0/n, {{{1}}} and substituting into the decay solution to obtain
Thanks! S B H arris 00:29, 30 September 2015 (UTC)
Just thought I'd let you know so you can see if it works for you. If there's something that can be improved, please let me know. Thanks, Morgan Phoenix ( talk) 04:33, 19 January 2016 (UTC)
Hello all. There is a quote:
and range over 55 orders of magnitude in time
In the interest of engaging and exciting those who may not understand what even 7 orders of magnitude of seconds means (human lifetime), perhaps some sort of comparison would drive home the magnitude (ha!) of the 55 orders of magnitude quote? Buzzm ( talk) 00:48, 25 January 2016 (UTC)
I would like to propose that this article be renamed to Nuclear decay. There is already an article for Particle decay, which can be "radioactive" as well, so I don't feel the title is very accurate, or at least is not very clear as to the distinction between Radioactive decay and Particle decay. I feel it would be cleaner to name this article Nuclear decay, and have Radioactive decay link to it, as that is usually what is meant. — Preceding unsigned comment added by 70.247.169.219 ( talk) 18:46, 26 March 2016 (UTC)
The diagram that shows all the isotopes possible plotted on N vs Z is cool. The diagram just below it that shows how various decay modes transition within the former diagram is cool. what's not cool is that they have contradictory axes; the top diagram has N vertically while the bottom one has Z vertically. The two could make beautiful harmony, if only they could agree. Also, in the result transition diagram, there is a small epsilon associated with beta+, a positron. I've never seen that convention before. Am I just behind the nuclear physics joke curve? :) SkoreKeep ( talk) 06:31, 3 January 2013 (UTC)
Oops, pardon me. The transition diagram is just above, not below, the N/Z plot. — Preceding unsigned comment added by SkoreKeep ( talk • contribs) 06:35, 3 January 2013 (UTC)
The epsilon stands for a a separate process called electron capture that always competes with positron decay, requires less energy, and produces the same transmutation. S B H arris 08:35, 3 January 2013 (UTC)
It was in the article and you only had to refresh, but here it is anyway:
M∧Ŝ c2ħε Иτlk 09:26, 3 January 2013 (UTC)
Is the symbol ε standard? I have never seen it used to mean electron capture before and am more familiar with EC. Anyway ε is not defined in this article, neither in the caption to the figure discussed above, nor in the accompanying text, nor in the tables of different types of decay. Nor is it defined in the article on Electron capture. If we are going to use this symbol in the figure we must define it, but I think it would be simpler to just write out electron capture in the figure itself. Dirac66 ( talk) 20:03, 3 January 2013 (UTC)
Look at
Isotopes of helium #Table: these isotopes appear to be able simultaneously emit a β− and split to two nuclei: 6
2He
→ 4
2He
+ 2
1D
+
e−
+
ν
e. This article
does not know such type of decay.
Incnis Mrsi (
talk) 18:21, 1 February 2013 (UTC)
but the mean life and half-life t1/2 have been adopted as standard times associated with exponential decay. Just about everywhere except nuclear decay, 1/e life is used. One exception is optics, where optical absorption is exponential base 10. (Or log base 10 if you do it the other way around.) Gah4 ( talk) 00:32, 13 October 2016 (UTC)
The theory as I read it was that the rate at which neutrinos pass through a body can influence the rate of radioactive decay of that body. Since the overwhelming proportion of neutrinos passing through the earth (or indeed our easily accessive solar system) is from the sun (an "almost" point source of neutrinos at planetary distances), then obviously any change in the neutrino-producing component of solar activity will change the neutrino flux and hence the radioactive decay rate, as will the distance from the Sun. But to repeat, I have no reference for it, so I'm only including it here as an anecdote.
The other significant part of this is that IF it is true, then with neutrinos passing through solid matter so easily, their effect on radioactive decay will be felt equally on the surface of the earth as it would be inside the earth, and at any depth. 124.184.13.246 ( talk) 08:56, 31 August 2012 (UTC)
I tried a link to statistical significance for Although these are constants, they are associated with the statistical behavior of populations of atoms. In consequence, predictions using these constants are less accurate for minuscule samples of atoms. but it was reverted. I had thought about law of small numbers, but that is a disambiguation page, and none of the choices are close at all. There are other ways to lose statistical significance, but not having enough data points is the usual way. Any other suggestions? Gah4 ( talk) 06:08, 13 October 2016 (UTC)
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Perhaps this page can be folded into the Radioactivity page? It seems a bit redundant having both...
Both are usefull, this one on the mechanisms and pyhsics, the other one for the seconadry effects of decay, on environment, bioloy etc.
Btw. does anyone know if there exists a formula by which, given the number of protons and neutrons, the half-life of a nucleus can be derived?
The above argument for maintaining separate articles here and at Radioactivity is no longer valid. We need to decide which article will be kept, and which will be made into a redirect. The case as I see it is thus:
-- Smack 06:26, 23 Nov 2004 (UTC)
Please add any new arguments to this list. -- Smack 22:09, 14 Nov 2004 (UTC)
I can see no problem with keeping both. Wikipedia is not written on paper and data can be held several times over in different places with minimal extra cost. The principal search term will probably be Radioactivity but a more detailed look at Radioactive decay, perhaps detailing the rate of decay of specific elements and isotopes would be very interesting and would be too much detail to hold on the Radioactivity article. Lumos3 09:43, 23 Nov 2004 (UTC)
Let's have another vote. Should this article live here, or at Nuclear decay? The present title is favored by a Google test, seven to one. -- Smack ( talk) 23:56, 24 Mar 2005 (UTC)
What determines which type of radioactive decay will happen? Thanks. -- Eleassar777 12:09, 30 May 2005 (UTC)
Are there any (simple) equations that roughly describe this? How do these factors interact? Thanks. -- Eleassar777 08:38, 31 May 2005 (UTC)
One rare decay process that is not mentioned anywhere is the emission of a carbon-14 nucleus. I think it's like spontaneous fission, but acts like alpha decay in that the nucleus that is emitted always has the same mass number (14).
Some isotopes of radium can decay by this method, such as Ra-221, Ra-222, Ra-223, Ra-224 and Ra-226.
Reference: Isotopes of Radium -- B.d.mills ( Talk) 03:13, 15 Jun 2005 (UTC)
Double electron capture is so rare most sources don't even say that it exists. My chart of the nuclides doesn't list it as a decay method, neither does environmentalchemistry.com. I have not heard of it other than here and will ask my professors when I get back to university. However, your quoted source does but it also lists the following types of emissions too:
-- metta, The Sunborn 15:05, 22 Jun 2005 (UTC)
No, it doesn't. -- Smack ( talk) 04:44, 18 September 2005 (UTC)
So does anyone want to fix the cadmium article? Ken Arromdee 21:20, 23 September 2005 (UTC)
I tried fixing it myself. However, the two sources above contradict. One says >1.2E21 years and the other says 3.1E19 years. Which is correct? Ken Arromdee 18:20, 19 October 2005 (UTC)
what type of radioactivity produces only energy waves
Is this the right page for clarifying the bewildering variety of measurements associated with radioactivity, or has this been done elsewhere? Joffan 01:13, 31 October 2005 (UTC)
How common is radioactive decay? Which materials exhibit radioactive decay and why? Where am I likely to encounter them? Rtdrury 05:12, 2 January 2006 (UTC)
BlueEVIL420 66.20.103.36 16:36, 24 February 2007 (UTC)
(template removed - request rejected. Vsmith 04:40, 24 March 2006 (UTC)
I am sure all of do not agree on the existence of true randomness.....I for one, do not belive it exists.....evrything is caused by something and also reacts in some way. An atom will not start behaving in a manner that is not triggered by something else. In case of radioactive decay, I am sure you all agree that we do not yet completley understand all the sub-atomic forces working, and their consequences.....so just because we do not know why, it is wrong to assume that something is truly random. In this article, there are several uses of the word random used in a sense implying that true randomness does exist. 'On the premise that radioactive decay is truly random...' etc... I simply wish to change the languge used throughout the article to eliminate this sense, but thought I should bring it out on the discussion board first. Again, my intention is only to slightly modify the language in those parts on the article, not to change or challenege any other factual information provided.
According to the article on randomness on wikipedia.... "The word random is used to express APPARENT lack of purpose, cause, or order." Hence true randomness seems to me as an oxy-moron.
Abhishekbh 04:23, 24 March 2006 (UTC)
I happen to think this simply introduces an unnecessary assumption, without reason, and should be rejected following Occum's razor. But in any case, I see no reason a priori to reject the very idea of causeless events. If you can't see the cause, you have no good reason to demand that something you can't find or point to, still exists.
And besides, if you reject causeless events, you are left with strict determinism, by excluded middle argument. Are you happy with determinism? I guess you must be <grin>. You have to be <grin>. S B H arris 23:02, 24 February 2007 (UTC)
I keep seeing the trefoil upside down in certain publications... is that wrong, or are both directions acceptable?
The measurements of activity I've seen are Bq/gram. I don't know how simple Bq would mean anything significant. In any case, I think its an important relation to have: the relation between half-life and decays/gram/second. Fresheneesz 18:58, 31 May 2006 (UTC)
Stimulus not a term usually found in context of radioactivity descriptions and is not found in the reference given. What are its meaning and its relevance for the article?
...predictions using these constants may be less accurate if the substances are in situtations that provide extra stimulus. [2]
Jclerman 13:06, 20 June 2006 (UTC)
The radiometric decay rates used in dating are totally reliable. They are one of the safest bets in all of science.
Nuclides are not nuclei. They have been edited. Jclerman 02:08, 24 June 2006 (UTC)
Modes of Decay has been merged into this page SuperTycoon 16:42, 15 July 2006 (UTC)
A recent edit
The summary for this edit to the "Decay chains and multiple modes" section asks "Is this really true? A given uranium isotope always ends in the same lead isotope, no?". I can't find a reference for uranium having multiple decay modes, but some isotopes of some elements do have multiple decay modes. The section also mentions 212Bi, which is a valid example according to the Decay chain article, so I edited the text to remove mention of uranium. The second part of the summary contains the hidden assumtion that a different decay mode early in a decay chain (or a "branch" to continue the chain analogy) will result in a different stable endpoint. This is not true; according to the Decay chain article, the two decay chains for 212Bi reconverge at 207Pb. DMacks 20:26, 31 July 2006 (UTC)
Is there a theory about what causes the randomness of decay? I mean why should some atoms go off immediately, and others wait, perhaps, millions of years?-- Light current 22:43, 25 September 2006 (UTC)
I think this article should have its own section describing the dangers of radioactivity. Now, it's included in the end of the "Discovery"-section as a historical note only. Kricke 01:27, 17 February 2007 (UTC)
.(Note from curious passerbyer, when it says "all but vanished," doesn't that mean it didnt vanish from the market? I mean it translates to me as anything happened but vanishing from the market. I might be wrong but didn't radioactive treatments vanish from the market? (Touche, my friend. I find your logic rather sensible.))
Are all matter radioactive? They say that only unstable atoms are radioactive, and that through radioactivity it eventually becomes stable again. So is it then no longer radioactive? Will the world one day be completely stable when everything has become stable? Or...? ► Adriaan90 ( Talk ♥ Contribs ) ♪♫ 18:35, 29 June 2007 (UTC)
I think a graph showing an exponential decline curve would be useful in this article. —Preceding unsigned comment added by 212.219.123.32 ( talk) 12:03, 4 October 2007 (UTC)
I know of the existence of a type of decay called negatron emission, however I do not see it listed on this page. Perhaps someone should add it. Nschoem 01:03, 21 February 2008 (UTC)
It has been discovered that nuclear deacy vares over time, or more accurately: with the Earth's distance from the sun. Can someone make a section of this please?
http://science.slashdot.org/science/08/08/29/1227239.shtml -- J-Star ( talk) 23:31, 29 August 2008 (UTC)
Q.: Shouldn't relativity be applied to the integral transformation points of a decay series for a better description of the passage of time? ie thinking about the clocks experiment and our static location in spacetime when an observation is made; the assumption of linear temporal decay from thenthere to herenow must be innacurate? (not only given a differential for time passed but also vector location changes as the earth spins etc). DGreenhill 151209 —Preceding unsigned comment added by 82.111.134.82 ( talk) 12:03, 15 December 2009 (UTC)
Is Radioactivity a physics or a chemistry related subject? —Preceding unsigned comment added by NoPity2 ( talk • contribs) 16:52, 14 October 2008 (UTC)
Originally, research on radioactivity was a branch of chemistry, because the first problem was to chemically isolate and identify the substance emitting the radiation. Nowadays I think things like "radio-chemistry" denotes the chemistry of compounds of radioactive elements, much as "organic chemistry" denotes the chemistry of compounds of carbon. For example, in medicine, you want to use compounds that can efficiently deliver the radioactive elements to the tissue to be radiated. Finding, making, and using such compounds is chemistry, not physics. WmMBoyce ( talk) 00:07, 29 September 2009 (UTC)
From Radioactivity:
From Marie Curie:
I feel that the introduction should acknowledge the monograph by Rutherford, Chadwick and Ellis first published 1930, latest edition 'Radiation from Radioactive Substances' Cambridge Univ.Press 1951 —Preceding unsigned comment added by Michael Nettleton ( talk • contribs) 15:19, 8 January 2010 (UTC)
PLEASE FIX THE SYMBOLS ---- They are showing as red error messages (could not parse.... etc) - scroll to bottom half of page. The section after the decay chains is riddled with them! 122.49.138.138, 13:27, 21 February 2009
I question the changes made to the intro paragraph on 20 May 2010 by Androstachys. First the word "spontaneously" was removed as "misleading" in the phrase "... an unstable atomic nucleus *spontaneously* loses energy by emitting ...". Why is this word misleading? Perhaps its meaning could be made clearer. I propose inserting the sentence "The emission is spontaneous in that the nucleus decays without collision with another particle."
In the same edit the word "currently" was inserted in the phrase "... it is currently impossible to predict when a given atom will decay ...", with a reference that does not justify the word "currently". I think a more accurate formulation would be "According to quantum mechanics, it is impossible to predict when a given atom will decay". This would clarify that not only do we currently have no theory to predict the decay of a given atom, but we also have a very general theory (accepted by the majority of physicists) which says that we can never predict the decay of a given atom.
I will wait a few days for comments before making these changes. Dirac66 ( talk) 16:27, 26 May 2010 (UTC)
The reference given for "according to quantum mechanics", however, does not mention quantum mechanics or how QM explains or predicts (no pun intended) that such a prediction is impossible. —Preceding unsigned comment added by 173.11.1.218 ( talk) 23:16, 24 November 2010 (UTC)
I'm not sure that the history section is correct. Pages like [3] [4] [5] [6] [7] [8] does point to that Abel Niepce de Saint-Victor might have discovered radioactivity before Becquerel. Reko ( talk) 18:15, 22 June 2010 (UTC)
Which types of atoms actually decay? There isn't even a summary in this Wiki article. I put a pretty good one in, and you removed it, because it's duplicated somewhere else. Okay, quick, people: without looking at Headbomb's edit summary, WHERE would you find such a thing? S B H arris 18:56, 13 September 2010 (UTC)
On the larger issue, whether a summary of the various types of atoms that are radioactive actually belongs in, or has "a place" in, the article on radioactive decay, is not for you to say-- it's a matter for consensus decision. Which I've now asked for, on the TALK page. As also, is the question of whether the mathematics of the solution of the first-order exponential differential equation has a place in this article, rather than the article that actually deals fully with the mathematics of this, which is exponential decay. Don't forget that much "sarcasm" is merely a serious logical suggestion that somebody doesn't like, because it exposes their biases. S B H arris 19:26, 13 September 2010 (UTC)
This discussion is becoming heated. May I suggest as a possible compromise that the article include a brief statement, that the summary of how many nuclides decay by each mode can be found in the article on Nuclide. This would make the information more accessible to interested readers of this article, while keeping the article from becoming unnecessarily long. Perhaps in the See also section, but with an explanatory comment describing the table, or else just prior to the See also section. Dirac66 ( talk) 00:59, 14 September 2010 (UTC)
It would be very nice for this article to indicate in some way, not only the different types of radiation, but also which types of radiation dangerous and what is considered a dangerous dosage level.
My understanding was that basically it's only Gamma radiation that can be extremely dangerous, but I'm not an expert.
Zuchinni one ( talk) 21:31, 17 October 2010 (UTC)
The "Danger of radioactive substances" section claims Marie Curie had a low exposure to radium and had been careful with it; but our Marie Curie article mentions that her papers and even cookbook are radioactive and dangerous to this day. Which is it? Comet Tuttle ( talk) 05:12, 3 November 2010 (UTC)
Could a knowledgeable editor add some content on the history of how the dangers of ionizing radiation were discovered? Comet Tuttle ( talk) 05:14, 3 November 2010 (UTC)
Re the following sentence added today by SBHarris: "The relationship of types of decays also began to be examined: for example it was found that beta decay almost invariably preceded gamma decay, and not the reverse."
Does this mean: 1) If a given nucleus emits a beta and a gamma, then the beta is emitted first? Or 2) If a given nucleus emits a gamma, then a beta is emitted first? Or 3) If a given nucleus emits a beta, then a gamma is emitted subsequently? Please clarify which is meant. Dirac66 ( talk) 21:35, 8 November 2010 (UTC)
We now have 3 red links for "bound state beta decay". Before anyone adds a new article on this subject, I would like to suggest that we instead add a new section to the existing article on beta decay. We can then point the links from this article to that section. Dirac66 ( talk) 00:56, 15 November 2010 (UTC)
There is no obvious mention that for the decay process A → B the equation
is the universal decay law for a nuclide A, nor is there the more generalized A → B → C
with solution
where specifically NA0 = initial number of nuclides of type A. All symbols with usual meanings. I will slightly tweak context for what it is, and try to add referances while at it.
Maschen ( talk) 22:07, 27 October 2011 (UTC)
Finished with my reformulation. You have a point Dirac66, - i'll add a link of analogy.
Furthermore I have a niggling feeling that people will complain about the overlap between parts of the exponential decay article and this one. For those that will: I don't care about arguments. For this article, the equations are explained in detail and in specific context of radioactivity, in that article there is not much explaination for the chain decay law as a differential equation itself - the whole point of what I just did is to outline the maths behind the law of radioactive decay...
Maschen ( talk) 18:00, 28 October 2011 (UTC)
how about a section on uses of radioactivity — Preceding unsigned comment added by 109.148.122.30 ( talk) 20:29, 17 December 2011 (UTC)
Section Explanation, second paragraph, last sentence: "The limits of these timescales are set by the sensitivity of instrumentation only, and there are no known natural limits to how brief or long a decay half life for radioactive decay of a radionuclide may be."
Actually the universe does have a speed limit of c, so that nuclear fragments cannot separate by a nuclear distance of 10-15m in a time shorter than 10-15m / c = 3 x 10-24 s. This is why there are several radionuclides with half-lives between 10-24 and 10-20 s, but none shorter. Except that the article now includes a value of 3 x 10-27 s for He-2, implying that the two protons separate 1000 times faster than the speed of light. This value is unsourced and I do not believe it, so I have marked it as Citation needed. See also my further comments at Talk:Isotopes of helium. Dirac66 ( talk) 14:58, 19 December 2011 (UTC)
![]() | This page is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
The introductory paragraph is entirely too detailed and much of the material therein needs to be moved to later paragraphs and trimmed out of the intro. — Preceding unsigned comment added by Zedshort ( talk • contribs) 20:38, 1 April 2012 (UTC)
>Actually, I have read the entire article and like most articles on wikipedia it is cluttered, poorly phrased and needs reorganizing, hence my attempts. I am sorry if I gave offense by adding the hypothetical process of positron capture but I find the potential of that process interesting and like to include it just for the sake of completeness. If there are more than five processes of radioactive decay I think they should all be added. Perhaps a table of those dozen or more methods would be the best format with all the products included. But from most of the sources I have read typically only three or five are listed. I wonder, have we had a dispute somewhere in the past as you seem to have taken offense at my being here and making these changes? I think I remember you adding to the article on the Energy-Catalyzer. Sincerely — Preceding unsigned comment added by Zedshort ( talk • contribs) 00:40, 2 April 2012 (UTC)
Hi,
the general solution to the recursive problem by Bateman's equations does not seem to be correct. The correct equation is shown at http://www.physicsforums.com/showthread.php?t=452474
may be someone can change this, with best wishes Wolfgang — Preceding unsigned comment added by 212.95.7.181 ( talk) 12:58, 12 April 2012 (UTC)
Hello all. The formula for Bateman's equations given in the physics forum link above and now on the wikipedia page does not agree with that given in Kenneth S Krane's Introductory Nuclear Physics (Unit II Nuclear Decay and Radioactivity, Chapter 6 Radioactive Decay, Page 173 in my copy). Krane doesn't have the decay constant after the sum term in the Nd formula. If someone could confirm and change I'd be much obliged. [This comment by 86.177.136.35, 24 June 2012]
For example, the article on Cadmium states that: "The two natural radioactive isotopes are 113Cd (beta decay, half-life is 7.7 × 10^15 years) and 116Cd (two-neutrino double beta decay, half-life is 2.9 × 10^19 years)." How is such an extraordinarily long decay rate calculated/predicted? 124.184.13.246 ( talk) 09:01, 31 August 2012 (UTC)
Try asking the reference desk. Wikipedia:Reference desk/Science -- Klausok ( talk) 11:20, 31 August 2012 (UTC)
Look for 'isomeric' instead of 'isometric' and if doing this myself is not illegal please reply telling me that i should have done then and there Khpatil ( talk) 14:54, 7 December 2012 (UTC)
Quote: "Primordial nuclides found in the earth are residues from ancient supernova explosions which occurred before the formation of the solar system."
EVIDENCE for this? ANY? EVIDENCE? AT ALL? — Preceding unsigned comment added by 78.156.126.230 ( talk) 15:36, 20 December 2012 (UTC)
As to the more interesting question of where heavier-than-iron nuclides come from, it's complicated. About half of the nuclei heavier than iron are s-process nuclei that required some slow cooking somewhere (like AGB stars where free neutrons come from alpha reactions on C-13 and Ne-22) and the rest are r-process nuclides that require a truly titantic neutron flux from some fusion bomb event (like the first H-bombs making Es and Cf out of U and Pu). The sites for this are probably high mass supernovae that aren't quite large enough to make black holes, but have as many free neutrons at the end as possible. Certainly U and Th were made that way, and I'll have to go through the tables to see about the other 30-odd primordial radioactives. Some may be s-process nuclides that haven't been (or at least were not REQUIRED to have been) put through a genuine supernova or even nova, so we'd be liars if we said that all such nuclides heavier than iron had. Apparently red giants make some really heavy nuclides by the s-process, dreging them up and saute-ing them, then eventually puffing them gently out into space to make later generation solar systems like ours. S B H arris 06:02, 21 December 2012 (UTC)
The article says:
"[...] Although the parent decay distribution follows an exponential, observations of decay times will be limited by a finite integer number of N atoms and follow Poisson statistics as a consequence of the random nature of the process. [...]"
I'm pretty sure that the exact distribution is not Poisson's; it is Binomial with parameters and . I have done the math derivation myself.
I added the "citation needed" template as a warning for readers.
GNU/Octave code to simulate problem: http://pastebin.com/UHsrfXu0 (comments in Spanish)
Generated image: http://postimg.org/image/dqe92tzkn/
(In the background you can see a 3D plot (with color) of the Binomial probability function (of N(t)) evolving with time)
— Preceding
unsigned comment added by
Francisco Albani (
talk •
contribs) 08:02, 19 June 2013 (UTC)
From the article:
I don't think having incorrect equations in an article is a good idea: when people are looking for the formula, they won't pay much attention to the text, and even when they know the last one is wrong, they may accidentally copy it (easy mistake to make: you look up from your paper, see a line that begins with what you just wrote, so you assume that's the one you were copying). I doubt that people who know differential equations would need to be told explicitly why the two terms don't have the same sign, and you certainly don't need an incorrect formula to explain the correct one. Ssscienccce ( talk) 19:14, 20 January 2014 (UTC)
This text, which appears under the "Discovery and History" heading, should be moved to the "Occurrence and applications" section:
That is, assuming it belongs in the article at all. There are numerous applications of radioactivity that are not listed anywhere in this article; Food irradiation, cancer treatment, tracing underground pipes, labeling chemicals for biological experiments, smoke detectors, radio-thermal generators,... That's just scratching the surface. There's no scientific reason why dating rocks and fossils is any more special than any of those. 129.42.208.183 ( talk) 23:10, 30 January 2014 (UTC)
You are welcome. Zedshort ( talk) 01:37, 30 September 2014 (UTC)
Otto Reifenschweiler also observed changes in decay rates in Tritium Reduced radioactivity of tritium in small titanium particles (published in Physics Letters A.)
Claus Rolfs has performed experiments in which he accelerated radioactive decay Half-life heresy: Accelerating radioactive decay
Should these two also be mentioned in the section ? -- POVbrigand ( talk) 14:13, 7 May 2012 (UTC)
Looking to the 3 figures on the reference nr. 29, "Evidence against correlations..." one has to conclude that their claim is not substantiated because a synchronous variation will not show on the graphs. On what basis they assume very unlikely ? quoting: "If the Jenkins proposal were correct, it is very unlikely that the alpha, beta-minus, beta-plus, and electron-capture decays of all radioactive isotopes would be affected in quantitatively the same way. Thus the ratios of counts observed from two different isotopes would also be expected to show annual variations."
79.168.86.244 ( talk) 18:14, 10 May 2015 (UTC)
This article just links to a few items on wikidata, I don't know why. Please make attention.-- 171.232.148.168 ( talk) 15:09, 15 June 2015 (UTC)
"Although these are constants, they are associated with statistically random behaviour of populations of atoms. In consequence, predictions using these constants are less accurate for small number of atoms."
I changed this to be somewhat *less* misleading (current edit):
"Although these are constants, they are associated with the statistical behavior of populations of atoms. In consequence, predictions using these constants are less accurate for individual atoms."
- Because deleting it yielded a reversion from another user. The original statement was patently misleading. The problem with small numbers of atoms is not with constants or statistical behavior, but rather with analytical techniques. Except in a few cases where half lives are too long to be very well constrained. So...it really is wrong/misleading. My best guess is that it was put in by a creationist type to cast doubt on the veracity of radioisotopic dating. Geochem. PhD here. I apologize if the format of this talk page edit is not perfect; I do not edit wikipedia with any regularity. Saw this error while perusing the page. Can someone with more clout on here delete the phrase and keep it that way? — Preceding unsigned comment added by Meteoritekid ( talk • contribs) 09:21, 12 June 2015 (UTC)
The last part of the "half-life" subsection contains a bit of LaTeX {{math|''t'' = ''T''{{sub|1/''n''}}}} that comes out nonsense (as {{{1}}} on all my browsers), and which needs to be fixed. But I don't see anything obviously wrong with it. Can somebody figure out what the second expression needs to be?
Here it is:
Mathematically, the nth life for the above situation would be found in the same way as above—by setting N = N0/n, {{{1}}} and substituting into the decay solution to obtain
Thanks! S B H arris 00:29, 30 September 2015 (UTC)
Just thought I'd let you know so you can see if it works for you. If there's something that can be improved, please let me know. Thanks, Morgan Phoenix ( talk) 04:33, 19 January 2016 (UTC)
Hello all. There is a quote:
and range over 55 orders of magnitude in time
In the interest of engaging and exciting those who may not understand what even 7 orders of magnitude of seconds means (human lifetime), perhaps some sort of comparison would drive home the magnitude (ha!) of the 55 orders of magnitude quote? Buzzm ( talk) 00:48, 25 January 2016 (UTC)
I would like to propose that this article be renamed to Nuclear decay. There is already an article for Particle decay, which can be "radioactive" as well, so I don't feel the title is very accurate, or at least is not very clear as to the distinction between Radioactive decay and Particle decay. I feel it would be cleaner to name this article Nuclear decay, and have Radioactive decay link to it, as that is usually what is meant. — Preceding unsigned comment added by 70.247.169.219 ( talk) 18:46, 26 March 2016 (UTC)
The diagram that shows all the isotopes possible plotted on N vs Z is cool. The diagram just below it that shows how various decay modes transition within the former diagram is cool. what's not cool is that they have contradictory axes; the top diagram has N vertically while the bottom one has Z vertically. The two could make beautiful harmony, if only they could agree. Also, in the result transition diagram, there is a small epsilon associated with beta+, a positron. I've never seen that convention before. Am I just behind the nuclear physics joke curve? :) SkoreKeep ( talk) 06:31, 3 January 2013 (UTC)
Oops, pardon me. The transition diagram is just above, not below, the N/Z plot. — Preceding unsigned comment added by SkoreKeep ( talk • contribs) 06:35, 3 January 2013 (UTC)
The epsilon stands for a a separate process called electron capture that always competes with positron decay, requires less energy, and produces the same transmutation. S B H arris 08:35, 3 January 2013 (UTC)
It was in the article and you only had to refresh, but here it is anyway:
M∧Ŝ c2ħε Иτlk 09:26, 3 January 2013 (UTC)
Is the symbol ε standard? I have never seen it used to mean electron capture before and am more familiar with EC. Anyway ε is not defined in this article, neither in the caption to the figure discussed above, nor in the accompanying text, nor in the tables of different types of decay. Nor is it defined in the article on Electron capture. If we are going to use this symbol in the figure we must define it, but I think it would be simpler to just write out electron capture in the figure itself. Dirac66 ( talk) 20:03, 3 January 2013 (UTC)
Look at
Isotopes of helium #Table: these isotopes appear to be able simultaneously emit a β− and split to two nuclei: 6
2He
→ 4
2He
+ 2
1D
+
e−
+
ν
e. This article
does not know such type of decay.
Incnis Mrsi (
talk) 18:21, 1 February 2013 (UTC)
but the mean life and half-life t1/2 have been adopted as standard times associated with exponential decay. Just about everywhere except nuclear decay, 1/e life is used. One exception is optics, where optical absorption is exponential base 10. (Or log base 10 if you do it the other way around.) Gah4 ( talk) 00:32, 13 October 2016 (UTC)
The theory as I read it was that the rate at which neutrinos pass through a body can influence the rate of radioactive decay of that body. Since the overwhelming proportion of neutrinos passing through the earth (or indeed our easily accessive solar system) is from the sun (an "almost" point source of neutrinos at planetary distances), then obviously any change in the neutrino-producing component of solar activity will change the neutrino flux and hence the radioactive decay rate, as will the distance from the Sun. But to repeat, I have no reference for it, so I'm only including it here as an anecdote.
The other significant part of this is that IF it is true, then with neutrinos passing through solid matter so easily, their effect on radioactive decay will be felt equally on the surface of the earth as it would be inside the earth, and at any depth. 124.184.13.246 ( talk) 08:56, 31 August 2012 (UTC)
I tried a link to statistical significance for Although these are constants, they are associated with the statistical behavior of populations of atoms. In consequence, predictions using these constants are less accurate for minuscule samples of atoms. but it was reverted. I had thought about law of small numbers, but that is a disambiguation page, and none of the choices are close at all. There are other ways to lose statistical significance, but not having enough data points is the usual way. Any other suggestions? Gah4 ( talk) 06:08, 13 October 2016 (UTC)