Created attachment 253 [details] Unexpected peak at 1195 (~415 keV) An unexpected gamma line was seen at 415 keV when I simulated Th-228 on a Ge crystal. Attached is a root histogram showing the problem. The red is Geant4 simulation, and the blue is data from the actual HPGe detector. X-axis is channel numbers (~3 channels = 1 keV). The unexpected peak can be seen at 1195 ch (~415 keV). I looked up the data files (G4PhotonEvaporation 3.0) and found that the intensity for the transition from 415 keV to ground state seems wrong: {{{ 4.152720e+02 1.766800e+02 1.600e+00 1+ 1.00e-11 1.00 2.110e+00 8.142e-01 1.274e-01 1.358e-02 9.960e-04 2.959e-02 3.512e-03 2.619e-04 9.967e-06 6.475e-06 1.049e-02 4.152720e+02 3.000870e+02 1.000e+02 1+ 1.00e-11 1.00 4.840e-01 8.156e-01 1.267e-01 1.329e-02 9.190e-04 2.940e-02 3.446e-03 2.439e-04 6.012e-06 4.329e-06 1.040e-02 4.152720e+02 4.152000e+02 4.400e+00 1+ 1.00e-11 1.00 1.850e-01 8.169e-01 1.261e-01 1.294e-02 8.722e-04 2.925e-02 3.358e-03 2.324e-04 4.290e-06 3.412e-06 1.032e-02 }}} From BNL NNDC Nudat2, Beta decay of Pb-212 to Bi-212: {{{ 176.68 5 0.052 % 6 9.2E-5 11 ...snip... 300.087 10 3.30 % 4 0.00990 13 415.2 0.0131 % 22 5.4E-5 9 }}} If we normalize the 300 keV line to 100, the 415 keV line should read 0.397 instead of 4.4 in the data. So either NNDC is wrong or G4PhotonEvaporation is wrong. (or am I wrong?)
Reassigned to correct category
I looked at 212Bi in Nudat2 using the "Level and Gamma" search, and I see the following: Elevel Jpi T1/2 Egamma Igamma Conv 212BI 415.272 11 1(-) ≤ 10 ps 176.68 5 1.6 2 M1 2.11 212BI 415.272 11 1(-) ≤ 10 ps 415.2 4.4 7 (M1) 0.185 212BI 415.272 11 1(-) ≤ 10 ps 300.087 10 100.0 1 M1 0.484 The gamma intensities are in agreement with those in PhotonEvaporation3.0/z83.a212, and also in the original ENSDF sheets. So I'm not sure where your value of 0.0131 for the 415 line came from.
But if you look for Pb-212 and click "decay radiation" at the bottom of the page, in the section "Gamma and X-ray radiation", you can find that 0.0131% number.
Yes, I see it now. So it seems there's an inconsistency in the NUDAT listings, with two different intensities (accounting for scaling) for the same gamma. This does happen from time to time and the best thing to do would be to inform the NUDAT people about this. Since you have some experimental evidence, I suggest you contact them, and inform us if they decide to resolve the discrepancy. At that point we'll change our database if required. For now I'll close the bug report, but for your local work, you can manually change your copy of the RDM database to have the smaller intensity value.
I got back from the guys who maintain ENSDF/NUDAT. They will correct the online database over the weekend. Excerpt of email from Jag Tuli of BNL: {{{ The author of evaluation of A=212, Eddie Browne, has since corrected its intensity in the adopted data set in accordance with its value in 212Pb B- decay. }}}
I just checked that they have changed the table online: http://www.nndc.bnl.gov/nudat2/getdataset.jsp?nucleus=212BI&unc=nds
Thank you for your follow-up on this. I've changed the intensity on line 8 in the file PhotonEvaporation3.0/z83.a212 from 4.4 to 0.4, according to the recent change in NUDAT2. This change will appear as part of an upcoming patch which is due within a month. The new photon evaporation data set will be PhotonEvaporation3.1. Until then, you can modify your local copy of PhotonEvaporation3.0.
