I am interested in the Pb212 and Pb214 beta decay. Many of the decays are non-unique first forbidden. I was aware of the fact that Geant4 (I am using G4.10.06.2) does not perfectly account for the forbiness and uniqueness, but if you read beta-decay Radioactive Decay Module documentation it looks like it does some approximation.
However, if you read the code, you will realize that the approximation is valid only for 210Bi. And this is only for thenon-unique 1st forbidden. For the 2nd or 3rd there is no comment, so it is not clear if it is valid or not.
Additionally, I find it weird that the RadioactiveDecay6.1.2/z83.a210 (the one for 210Bi) does not have any flag.
I really find it misleading and confusing. Am I missing something?
I think we are missing the README_RDM file of the dataset (at the base of the folder). In there you can find documentation on the format of the dataset.
In the case of beta- or beta+ decay, there will often be a sixth column
describing the “forbiddenness” of the particular decay channel. This is
indicated by the tags firstForbidden, secondForbidden, thirdForbidden,
uniqueFirstForbidden, uniqueSecondForbidden, uniqueThirdForbidden, which
determine the shape of the beta spectrum.
What it does not explicitly says is that the default one is Allowed as seen from a comment in G4VRadioactiveDecay::LoadDecayTable where the files are parsed.
That explains the lack of a flag in the data file you are looking for.
You are indeed correct at noticing that the comment in the code for firstForbidden type is
// Parameters for 1st forbidden shape determined from 210Bi data
// Not valid for other 1st forbidden nuclei
And if one looks into the G4BetaMinusDecay (for instance) one sees that the shape of the spectrum is set up according to the G4BetaDecayType via the G4BetaDecayCorrections without any filtering. So, this quick look would indicate that all firstForbidden decays use the same parameters. This is probably true for the following nuclei
Thank you for the reply, I appreciate a lot. If you are talking about the README in the G4RadioactiveDecay, it is actually there. What I am complaining about is that in the documentation it is not explicitly written, and this makes it misleading.
Regarding the firstForbidden
So, this quick look would indicate that all firstForbidden decays use the same parameters.
Do you agree that this is pretty important, and it is not explicitly written anywhere besides the code? Also, given the fact that it looks like the correction implemented is valid only for 210Bi.
Last but not least, do you know where these values come from? And what about the other beta type transition? Where do the corrections come from?
as I said in my original reply. It affects a handful of nuclei. You are correct, the documentation is not clear and it should be improved and expanded.
If I may also raise another problem, the references listed in the documentation page are impossible to find (e.g., E. Konopinski. The Theory of Beta Radioactivity. Oxford Press, 1966.)
