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definition of radioactive decay
Hi i was just wondering why it isnt explicitly pointed out that for an atom to be considered radioactivelly decaying it would have to be emitting ionizing radiation. Without ionizing explicitly being stated, emittance of infrared radiation could also be considered radioactive decay, no? "Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation" it is not clear if in this sentence "unstable" is ment as a vague term, or in the physics sense of the atom containing more energy than its ground state. If the latter, once again, the absorption of lets say yellow light which results in for example the emittance of infrared radiation could be considered radioactive decay. I am in no way trying to be rude, i just ran into this problem while trying to understand the exact definition of radioactive decay. If i was wrong anywhere in my comment please do point it out.
Thanks for the suggestion. I suspect that "ionizing radiation" was not mentioned because it is a somewhat old-fashioned term not much used now. However I found it mentioned in an introductory chemistry text and attributed to the Curies, so I have now included it in the History section, as well as a link to the article Ionizing radiation which explains it in detail.
Dirac66 (
talk)
20:06, 18 February 2021 (UTC)reply
The modern terminology used to describe each radioactive decay process is to identify the exact particles emitted in each decay process as α particles, β particles, γ rays etc. However I will admit that the term "ionizing radiation" is still accurate as a general term, and is still used in many other contexts. See the article
Ionizing radiation for more detail.
Dirac66 (
talk)
15:17, 14 September 2023 (UTC)reply
On the decay modes in the table
Hi everyone. I just wanted to ask about the table displaying the radioactive decay modes, since I'm currently working on the "Isotopes of" pages. While I was editing some of the pages, I found that NUBASE2020[1] lists a couple of decay modes that are not mentioned in the table. Furthermore, there is some notation that I'm not really sure how to go about adding it to the decay modes:
(note: "α" is used in the paper (PDF page 19) as an example)
"α ? means that the α-decay mode is energetically allowed, but not experimentally observed
α=? means that the α-decay is observed, but its intensity is not experimentally known"
I would generally favour listing in an encyclopedia only what has been observed. So modes marked "α ? by NUBASE I would omit entirely, and modes marked α=? by NUBASE I would list as α-emitters but not mention the intensity.
Dirac66 (
talk)
19:55, 2 March 2022 (UTC)reply
Some radioactive isotopes (not all) have practical applications, which are often mentioned in the articles on isotopes of each element.
Dirac66 (
talk)
19:59, 2 March 2022 (UTC)reply
2. Defining source is {{NUBASE2020}},[1] [sole source?] see ...
3. ... see table "Decay modes and intensities" on e-page 19–20 / 181 (page 030001-18, -19). This table has 2527 entries all-in-all (α ... SI; also 2n, 2p).
4. Table header notes the "?" notation: α ?, α=?. How should this appear in the table?
5. Also in this table, in top, is local uncertainty notation, to be read as "a=25.9 % ± 2.3 %" (example): editors are supposed to werote the result not the NUBASE notation (not the meaningful-space-notation)
6. Also: aim is to make these correctly & easily available in our Big Isotopes tables, ~118, both in-table (for editor to input; can we easify?) and as optional standard footnote by {{Isotopes table}} header (expanding the
current list of |notes=CD, EC, IT, SF, n, p, see example
Isotopes of helium § List of isotopes. Both as editors input, and in default-text footnotes.
OK, below is the new 2020 table. The complete 2020 list is in there, with change notes. Also, some disappeared/not-found 2016-entries are listed. From here, I need physics input. Could someone, for example, start filling the empty/new cells in {{Decay modes/2020}}?
DePiep (
talk)
13:41, 3 March 2022 (UTC)reply
Working
The table now has all curent and previous DMs. The physics, wikilinks, text need a check. Also, some merge or additions could be needed.
sort: order in 2020 NUBASE Table; also groups related DMs. Also ID.
Code: simplified input, eg for templates in Isotope infoboxes (|dm=b+2n; future use)
2020 change: change re 2016 table, or change re enwiki usage so far. (many MDFs are not used)
Mode: some merges with 2016? Do we use the rare and new ones?
Name: descriptive name + wikilink (many missing, some trivial & not helpful)
@
DePiep: Couple of days late, but from what I can tell, it looks quite good so far - great job! :D I just have a couple of comments and suggestions.
(DISCLAIMER: I am not an expert in nuclear physics. If I've gotten anything wrong, please feel free to tell me :D)
I've just checked the original NUBASE2020 paper, and it states that "IS" is their abbreviation for "isotopic abundance". Since we already have that in
Template:Isotopes_table (i.e. the "Natural abundance" column), in my opinion we could do away with it entirely.
For your question regarding whether 260 (heavy cluster emission) and 262 (cluster decay) are the same, I've just checked the nuclides listed to undergo cluster decay on
the Wikipedia page on the same subject with NUBASE2020, and so far, all of the nuclides listed that are correct (i.e. almost all of them) correspond with what NUBASE2020 refers to as "heavy cluster decay". In other words: as far as I can tell, heavy cluster emission and cluster decay are the same thing.
This might be just me, but, assuming that I've read the new table correctly, I don't 100% get why spontaneous fission has been removed from the new table - it pops up in both NUBASE2016 and NUBASE2020. There are a couple of the heavier nuclides from the table on the
Cluster decay page that are also listed in NUBASE2020 with SF as a decay mode (you'll find them everywhere from nuclides with mass numbers of 221 onwards).
As you've mentioned before in this talk page, NUBASE2020 (and NUBASE2016 as well, for that matter) both clarify what they refer to as "β+ decay" is equal to "β+ = ε + e+", where "ε" is electron capture and "e+" is positron emission. Hopefully this may help clear up some confusion?
Great job anyways, and thanks for taking my proposal seriously. :D
@
DePiep: Right, I'm onto this. I checked NUBASE2020 and it gives only electron capture for 7 Be ; I then checked
NuDat (which is maintained by IAEA) and got to the
page on 7 Be , which corroborates NUBASE2020. However, it also does give some values under the heading "Gamma and X-ray radiation". I checked
Electron capture and it does mention that a gamma ray is also emitted during electron capture. I also managed to find
this helpful diagram, and, from what I can tell, a gamma ray is indeed emitted when 7 Be decays via electron capture (ε).
While we're at it, I got a couple of other small things we could do to fix up the table:
Since "IS" in NUBASE2020 is used as a shortened way of saying "isotopic abundance" (which is, quite clearly, NOT a decay mode), I think we could remove it from the table entirely.
"Spontaneous fission" is also given in NUBASE2020 as a decay mode, so I think that we could keep that in the main table as well and move it with the other decay modes.
Assuming that we do decide to go ahead and use the NUBASE notation for decay modes, I think, if possible, it would also be valuable to provide other notation methods that are frequently encountered in the literature, for obvious reasons. Not everyone may be familiar with the NUBASE notation, and we don't want to give the incorrect impression that the NUBASE notation is the only "correct" notation for decay modes.
Also, I've put this up on
Wikipedia talk:WikiProject Physics to try to get a bit of help over here and (hopefully) speed up the process. In the meantime, I think this gives me the green light to get rid of the "gamma decay" row for 7 Be . Let me know if you've got any other questions, and please keep me in touch with any progress on the isotope tables as well! :) —
MeasureWell (
talk)
08:11, 21 March 2022 (UTC)reply
Hi, folks! I'm reasonably conversant with radioactive decay, but there's so much back-and-forth here, I'm a little fuzzy on what the unresolved issues are. What can I help with?
PianoDan (
talk)
23:15, 21 March 2022 (UTC)reply
@
PianoDan: Sorry for the late reply! Thanks for offering to help – the main issues here (most important issues at the top), as far I as can tell, are these:
Check that the AZ values for β+ and β+-delayed decay modes from NUBASE2020 are correct
Check that the decay modes given are consistent with NUBASE2020
Check that the descriptions for each decay mode are correct
Also, I think that after it would also be a good idea to add a footnote to the β+ and e+ rows to indicate differences in notation, because I'm quite sure that most readers will be unfamiliar with the NUBASE2020 notation. Once again, thanks for the help!
* Check that the AZ values for β+ and β+-delayed decay modes from NUBASE2020 are correct
- As far as I can tell, these are accurate. I agree with the assessment that "Heavy Cluster Emission" and "Cluster Decay" are the same thing, and that 24Ne was simply a particular example chosen for the table. I'll add an additional line to the table as a suggestion for what a combined line could look like.
PianoDan (
talk)
16:50, 7 April 2022 (UTC)reply
On second thought, line 262 seems mostly fine, although I'm confused by the AZ numbers. Shouldn't that last value simply be (A-A1, Z-Z1)? If you add A1, Z1 back in, you're just back where you started.
PianoDan (
talk)
16:56, 7 April 2022 (UTC)reply
Replying to myself: Oh, I see - the intent is to show both daughter products. In that case, I think they should be separated by a comma, a semicolon, or an ampersand - anything but a plus sign, which could confuse the issue.
PianoDan (
talk)
17:34, 7 April 2022 (UTC)reply
* Check that the decay modes given are consistent with NUBASE2020
* Check that the descriptions for each decay mode are correct
Comments:
- What is the purpose of the "code" column, as independent from the "Mode" column? Why do we have both?
- I agree that 60 and 62 are the same thing. ε is the more current usage, per NUBASE2020. I don't think the note is necessary, since the name is right there.
- If we want to be consistent with NUBASE, 2p and 2n should be "2-proton emission" and "2-neutron emission", not "double neutron emission" and "double neutron emission." On the other hand, NUBASE DOES use "double decay" and "double decay" The inconsistency is a little weird, but I think we should mirror it.
- In that vein, the names for rows 80 to 110 should use the β symbol, rather than the word "beta" for consistency with both NUBASE and the other rows in the table.
- Beta Decay general observation:
In NUBASE, β+ decay is used to indicate that the nucleus can decay by EITHER electron capture (ε) or positron emission (e+), and the rate of β+ decay is the combination of the two. (β+ = ε + e+) Do we wish to indicate that in some way?
- Rows 3xx ARE in NUBASE 2020, so should be included. To be clear, the difference between cluster decay and spontaneous fission is that in cluster emission, the SAME smaller nucleus is emitted each time, where SF can produce a range of daughter products. We should probably mention that explicitly in the SF line. [3]
What is the purpose of the "code" column, as independent from the "Mode" column? Why do we have both?
I think you're better off asking
DePiep that question, since they are the original creator of this template. Unfortunately, they're currently busy IRL, so it might take a while for a response.
In NUBASE, β+ decay is used to indicate that the nucleus can decay by EITHER electron capture (ε) or positron emission (e+), and the rate of β+ decay is the combination of the two. (β+ = ε + e+) Do we wish to indicate that in some way?
Yeah, sure, go ahead. Since other websites generally use the ENSDF notation (i.e. ε = electron capture, β+ = positron emission) to indicate these decay modes, I think that it would definitely help to make it clearer to readers who might be unfamiliar with the notation used in NUBASE.
Rows 3xx ARE in NUBASE 2020, so should be included. To be clear, the difference between cluster decay and spontaneous fission is that in cluster emission, the SAME smaller nucleus is emitted each time, where SF can produce a range of daughter products. We should probably mention that explicitly in the SF line.
Yup, good idea – also, thanks for the clarification: I initially got confused between the two as well :).
Tell you what: I'll move the rows over and change the names of 2p and 2n to those in NUBASE2020, while you can add the descriptions and indications (you're an expert in this, I'm not). Thanks for the quick response! —
MeasureWell (
talk)
01:25, 8 April 2022 (UTC)reply
@
PianoDan: on the code column: is not for publication, but a preparation for usage in templates (like {{Infobox isotope}}), so that input is keyboard-easy and formal presentation is standardised. (Also helped me to find same/different forms in the decay modes). -
DePiep (
talk)
04:47, 8 April 2022 (UTC)reply
OK, I've updated all the descriptions and names to match NUBASE as well as the best of my understanding of how they all work. Given that beta+ decay is a compound rate in NUBASE, I'll let y'all figure out exactly what should be going on with redirects in that row. I also moved "Heavy Cluster Decay" to the bottom and cleared the note for electron capture. Let me know if there's anything else you need!
PianoDan (
talk)
16:45, 8 April 2022 (UTC)reply
@
PianoDan: I've just noticed that for some strange reason, isomeric transition (IT, which is given in NUBASE2020) is not listed on the table, and the decay name for β−SF is missing. I'll quickly go add the name for β−SF – is it possible to add IT to the table as a decay mode? Thanks for the help! —
MeasureWell (
talk)
09:16, 15 April 2022 (UTC)reply
@
PianoDan and
DePiep: I'm over a month late to this issue, but I've just gone ahead and added "IT" to the encoding for
Template:Decay modes/2020, and from my end, it looks like the encoding problem has been fixed. I've also moved some of the encodings for decay modes that are not intended to be in the final table to the "2016" section.
I think the tablew is fit for going live. Tough sourcing. Unfortunately, this month I have no time for it. So I'll be back next week, ans pblush it (if you've not done so already). -
DePiep (
talk)
05:43, 23 May 2022 (UTC)reply
NUBASE 2020 table: now live
Done I've put table {{Decay modes/2020}} live as is, using all data rows (modes) in NUBASE 2020.
A free neutron or nucleus beta decays to electron and antineutrino, but the electron is not emitted, as it is captured into an empty K-shell; the daughter nucleus is left in an excited and unstable state. This process is a minority of free neutron decays (0.0004%) due to the low energy of hydrogen ionization, and is suppressed except in ionized atoms that have K-shell vacancies.
@DePiep: Would it be possible to edit the line Cluster decay in your table? Normally I would do it myself, but I cannot find the source code to modify.
Suggested changes: 1. Mode column: Delete 24Ne because it is not the only possible cluster emitted. 2. Action column: Add at the end: Examples C-14 and Ne-24. (These are 2 of the most frequent examples as per the list in the article Cluster decay.
Dirac66 (
talk)
16:02, 29 October 2023 (UTC)reply
@Double sharp: Yes, you have corrected the table as I asked. Thank you for the correction and also for pointing it out. I did not notice the change since because it does not appear in the revision history. Whatever method you used to correct the table is quite mysterious for someone used to standard Wikipedia edits, and if I now look at a revision before the date of the request above (29 Oct 2023) the system claims that this line was already as it is now, which is not true. I am glad you knew how to do it.
Dirac66 (
talk)
22:58, 28 November 2023 (UTC)reply
Wiki Education assignment: 4A Wikipedia Assignment
This article was the subject of a Wiki Education Foundation-supported course assignment, between 12 February 2024 and 14 June 2024. Further details are available
on the course page. Student editor(s):
Alliemoreno (
article contribs). Peer reviewers:
Samiam25.
The article claims, without a reference, that radioactive decay is analogous to an avalanche from a snowfield on a mountain. The entire paragraph mixes simple classical ideas with bogus quantum ones. It talks about entropy and "over a larger number of quantum states". The energy of decay is down hill even ignoring entropy as far as I know. That's one of its most interesting characteristics. Radioactive decay is exactly not like classical systems. Am I wrong here?
Johnjbarton (
talk)
01:52, 31 May 2024 (UTC)reply
The paragraph following our snowfield seems equally dubious to me.
Such a collapse (a gamma-ray decay event) requires a specific activation energy.
I've never heard of this. The paragraph ends with a reference to
Milonni, Peter W. "Why spontaneous emission." Am. J. Phys 52.4 (1984): 340-343.