Negative nuclide ID's in ENSDF data?

[Paul Wilson]

Hello all, (and especially Cameron Bates)

When accessing some of the decay scheme data that PyNE imports from ENSDF, we find some nuc IDs that are negative.

While the nucname documentation says that "* Negative nuclides have no meaning (yet).", I was wondering if anyone familiar with ENSDF could explain why it would generate negative nuc ID's?

Thanks in advance,

Paul

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Paul P.H. Wilson (he/him/his)
Grainger Professor of Nuclear Engineering
Chair, Department of Engineering Physics
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Computational Nuclear Engineering Research Group

[dbrown]

Hi,

I just saw this thread and am wondering if it is resolved...  According to E. McCutchan (the ENSDF Library Manger), I quote:

The database wouldn’t let me put a negative nuc ID in (this is assuming that their nuc ID and our nuc ID are the same thing).  

The only thing I can think of relates to this statement “Negative nuclides have no meaning (yet).",

Some of the superheavies nuc ID’s are not 123AB – but 123117 – that is, where an element has not been named – the Z value is used instead.

If you have an explicit example, we might be able to run the problem down.

Dave

[Paul Wilson]

Hi Dave,

We were able to confirm that Cameron inserted the negative in his processing of the ENSDF data when he wrote the code:

I’m pretty rusty on this, but my recollection is that ENSDF data declares energy levels in two different places, one is in “level data” and the other is in “decay data”. I’m pretty sure the negatives come about when a level declared in “decay data” does not match closely to any level in “level data”. The connotation is “this is the closest level I could find, but it doesn’t match within reason”. From git blame, it looks like ”reason” was defined arbitrarily by me as 3 keV to get U transition states to come up as valid . At the time I think Anthony and I had a few conversation with the nuclear data community about feeding this back to update ENSDF files (or as an additional check that could be run for new decay data files), but it never went anywhere.

So I can confirm that it doesn't come from the original data.  Sorry that this response did not include the list.

Perhaps I should add an issue that covers the circumstance that Cameron notes above, so that a better solution can be devised.

Paul

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