Uncovering Half-Life Data for Odd Isotopes: A Search for Fission Products

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    Half-life Isotope
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Discussion Overview

The discussion centers on the search for half-life data of specific odd isotopes identified as fission products. Participants explore various databases and resources to find this information, focusing on the first excited states of the isotopes listed.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant lists seven isotopes for which they cannot find half-life data, including 74-As-m1 and 109-Ru-m1.
  • Another participant suggests a database link that may contain the needed information.
  • A participant reports partial success in finding data for some isotopes but not all, expressing frustration over the lack of information.
  • Another participant provides a link to a different database, noting that it may have some of the isotopes listed but questions the meaning of "m1" in the context of excited states.
  • The original poster clarifies that "m1" refers to the first excited state and mentions that the isotopes are not rare fission products, providing yield percentages for some of them.
  • A later reply reiterates the search for half-life data, stating that they found some information but clarifying that the numbers provided earlier refer to the ground state rather than the first excited state.
  • One participant mentions a roundabout method of finding information through a UK paper linked from a database, indicating the complexity of the search process.

Areas of Agreement / Disagreement

Participants express varying degrees of success in finding the requested half-life data, with no consensus on the availability of the information for the first excited states of the isotopes. Multiple competing views on the reliability of different databases are present.

Contextual Notes

There are limitations regarding the definitions of excited states and the specific isotopes being discussed, as well as the potential for incomplete data in the suggested resources.

Moniz_not_Ernie
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The Sigma database at Brookhaven lists seven isotopes as fission products for which I can't find half-life data. I've tried nea6287-JEFF-20-1, the NuDat_2 web site, Nuclear Wallet Cards and Wikipedia. Anybody have any other ideas?
The isotopes are
74-As-m1
85-Se-m1
86-Br-m1
109-Ru-m1
109-Rh-m1
143-Xe-m1
162-Tb-m1
 
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Ooh, so close. Got the first one on the list, then went 0 for 6.

Thanks.
 
You may want to check out these databases. http://www.nndc.bnl.gov/endf/b7.1/lists/dec-ENDF-B-VII.1.endf.listis a list of all the isotopes in the ENDF/B-VII.1 decay sublibrary. A quick look shows it has at least some of the isotopes. It doesn't say anything about meta-stable states for the ones I looked at so hopefully you mean m1 is the ground state instead of first excited state.
 
Sorry. I do mean the first excited state. None of the isotopes on my list show up on the list you provided.
These aren't exactly rare fission products. The max yield for 109-Ru-m1 is over 1%, albeit for 142-Am-m1 as the fuel. For 85-Se-m1 it's ~0.5% for 233-U and 235-U. I expect they aren't much of a problem in the waste stream because of short half-lives. I'll mention them as a caveat in my assumptions.

Thanks, though.
 
Moniz_not_Ernie said:
The Sigma database at Brookhaven lists seven isotopes as fission products for which I can't find half-life data. I've tried nea6287-JEFF-20-1, the NuDat_2 web site, Nuclear Wallet Cards and Wikipedia. Anybody have any other ideas?
The isotopes are
74-As-m1
85-Se-m1
86-Br-m1
109-Ru-m1
109-Rh-m1
143-Xe-m1
162-Tb-m1
http://atom.kaeri.re.kr/ton/
Did you look here? I got the results for all (I am not sure what you mean by m1).
I got for the particular isotopes: As 17.77 days, Se 31.7 s, Br 55.1 s, Ru 34.5 s, Rh 80 s, Xe 0.30 s, Tb 7.60 min.
 
To mathman, re http://atom.kaeri.re.kr/ton/
(This forum doesn't indent enough!)
Yes I visited the Korean site, twice. On my second visit I followed one reference URL back to a UK paper on PDF at Brookhaven. A bit roundabout, but very worldly. The PDF topic is not really half-lives, but they use them to describe the excited states. The PDF doesn't label them m1, m2, etc. I got the 74-As-m1 half-life from the Korean site, then 109-Ru-m1 from the PDF. Four more to go.
The numbers you gave above are for the ground state. I'm looking for the first excited state (-m1).