Decay X-ray energy library

_Geant4 Version:_4.11.0.2
_Operating System:_openSUSE Leap
_CMake Version:_3.17.0

tldr: where can I find the geant4 library for X-ray energies?

Hello Geant4 experts

I have noticed a possible problem with X-ray energies of 207Bi in Geant4.
I am simulating the radioactive decay of 207Bi using the /gps/particle ion method, and using the option 4 physics list. Part of this decay are some X-rays following atomic deexcitation following conversion electron decay. I read that the radioactive decay data used by Geant4 is based on the ENSDF files.
Below are the energies of the peaks I found on NuDat (sorry for the ugly table, as a new user I am only allowed one embedded media piece):

         |Energy (keV) | Intensity

XR ka2 | 72.805 | 21.4 % 5
XR ka1 | 74.969 | 35.7 % 7

And here are the starting energies produced by my simulation:

As you can see there is a slight difference (± 200 eV), enough that it noticeable when I try to calibrate my detector. I have tried to look up the libraries to see if it is possibly a typo, but I can only find the radioactive decay data relating to gamma, conversion electrons, betas, … but not the atomic deexcitation following the conversion electron decay.

Does anyone know where I can find these libraries, or has an idea of something I might be doing wrong with my simulation?

Any help is appreciated :smiley:


your case is complicate. The process starts from 207Bi, what is the initial excitation energy?
Radioactive decay data are available in $G4RADIOACTIVEDATA, where all avaiable in Geant4 decays are described. After the decay atomic shel of the nucleusl is modified and atomic de-excitation module is used for generation of atomic de-excitation cascade, data for which is taken from $G4LEDATA. On any step of these process may be issues. However, from your post it is not easy to understand what is wrong.


If gamma or e-

here, a macro for example rdecay01 (inspired from atomicDeexcitation.mac) and the plot of gamma spectrum (the bin is 20 eV).

cknap.mac.txt (584 Bytes)

the same macro, with a binning closer to yours.

cknap.mac.txt (582 Bytes)