| Summary: | Wrong X-ray de-excitation of Am241 decay daugther if PIXE is OFF | ||
|---|---|---|---|
| Product: | Geant4 | Reporter: | Andrea <niso2012> |
| Component: | processes/electromagnetic/xrays | Assignee: | Vladimir.Ivantchenko |
| Status: | ASSIGNED --- | ||
| Severity: | normal | CC: | alvaro.tolosa.delgado |
| Priority: | P4 | ||
| Version: | 10.6 | ||
| Hardware: | PC | ||
| OS: | Windows | ||
| Attachments: |
Comparison gamma ray spectra of Am241 decay with and without PIXE
Tracking output of an event with the emission of 102 X-ray in 59 keV trnsition with PIXE OFF |
||
Created attachment 623 [details]
Tracking output of an event with the emission of 102 X-ray in 59 keV trnsition with PIXE OFF
Hello, thank you for pointing to this problem. Can you, please, describe what kind of application is used? Is it one of Geant4 examples or more complicate code? VI Hello, I'm using my own application, but I have performed some tests with another independent application and I have obtained the same results. While I was trying to reproduce this issue with one of the examples, I have noticed some interesting behaviors that could be useful to understand this behavior: 1. In my app (and also in the other I have tried), the G4RadioactiveDecayPhysics is used, which uses the G4RadioactiveDecayBase, while the new examples use the new G4Radioactivation. If I use the G4Radioactivation in my code, this issue is no longer present. 2. This issue is not present also if I use the G4EmStandardPhysics, but it is present if I use other EM Physics Lists, such as option3 or Livermore. And, as I have already reported, if I turn ON PIXE, the issue is not present also with the option3 and Livermore PL. Please, let me know if additional information is required. Thank you for the assistance Hello, is it possible to repeat the check with 10.7beta? Vladimir Hello, I performed the same tests with G4.10.7.b01 and the results are the same. If deexcitationIgnoreCut is set to 1 the high energy X-Ray peaks appear. Let me know if you need other tests Thanka a lot Andrea Hi, I tried to reproduce the issue, running the example rdecay01 with the following macro file, evolveed from Co60.mac. ############## # macro for rdecay01 # /control/cout/ignoreThreadsExcept 0 /control/verbose 2 /run/verbose 1 # /gun/particle ion /gun/ion 95 241 /process/em/fluo false /process/em/auger false /process/em/augerCascade false /process/em/pixe true /process/em/deexcitationIgnoreCut false # /tracking/verbose 2 /run/beamOn 1 /tracking/verbose 0 # /analysis/setFileName Am241_PIXE /analysis/h1/set 1 1500 0. 1500 keV #e+ e- /analysis/h1/set 2 1500 0. 1500 keV #neutrino /analysis/h1/set 3 1500 0. 1500 keV #gamma /analysis/h1/set 6 1000 0. 2500 keV #EkinTot (Q) /analysis/h1/set 7 1500 0. 15e3 keV #P balance /analysis/h1/set 8 1000 0. 100. year #time of life /analysis/h1/set 9 1000 1. 3. MeV #EvisTot # /run/printProgress 100000 /run/beamOn 1000000 ############## I tried with all atomic processes set to false, only PIXE to true, and all set to true. The histogram 3, corresponding to gamma is the same in the 3 cases. I tried with geant4-11-01-patch-02 [MT] |
Created attachment 622 [details] Comparison gamma ray spectra of Am241 decay with and without PIXE In the simulation of the decay of Am241 and a lot of X-rays from K shell (101.574 and 97.498 keV) are produced if PIXE is OFF mainly as a consequence of these internal conversion transitions: 59.54 -> 0 keV and 102.96 -> 59.54 keV. (seen with /tracking/verbose 2). It is not possible: in fact from that excited state no internal conversions on K shell are allowed (the PhotonEvaporation file is correct, in fact, the probability is set to 0). I if simulate the Am241 decay gamma spectrum of an HPGe detector, I see that the spectrum is very different from the experimental one because these (and other) high energy X-ray peaks are should not be present. If I turn ON the PIXE, these X-rays are not produced with this high probability anymore and the “gamma spectrum” of the Am241 decay is compatible with the experimental one. There should not be an interaction between PIXE and atom deexcitation from radioactive decay. Important note: I have observed this behavior from version 10.5 (still present in 10.6 and 10.6.p01). The behavior is instead correct in the 10.4.p03. I don't know if this problem affects other nuclei. I have attached a comparison of the HPGe simulated spectra of Am241 with and without PIXE (red and blue respectively).