Created attachment 417 [details] Conversion electron spectrum in Geant4 10.2.p02 In bug http://bugzilla-geant4.kek.jp/show_bug.cgi?id=1781 I reported that in version 10.2, the flag G4NEUTRONHP_USE_ONLY_PHOTONEVAPORATION did not lead any more to the creation of conversion electrons after the neutron capture in Gd. In version 10.2.p02 conversion electrons are again created, but the conversion electron spectrum shows that only K,L,M shell conversion electrons from the lowest transition levels (89 keV for 156Gd after capture in 155 Gd, 79 keV for 158 Gd after capture in 157 Gd) are present. Higher transition levels do not contribute (see attached spectrum). In Geant4 version 10.1 the spectrum looked different, also the higher levels contributed conversion electrons.
Created attachment 418 [details] Conversion electron spectrum in Geant4 10.1
I noticed that it's not only the conversion electrons that are not correct, but also the gamma spectrum. Please have a look at: http://hypernews.slac.stanford.edu/HyperNews/geant4/get/hadronprocess/1571.html
As additional info, I'd like to add an email by Michel Maire: HI all, Let me underline Dorothea observations : Thermal neutron capture on 157Gd; therefore we observe gamma deexcitation of 158Gd. With USE_ONLY_PHOTONEVAPORATION, the gamma deexcitation scheme differs radically from 10.1 to 10.2 This does not happen with default neutronHP Where this feature is documented ? I attach outputs and gamma spectrums : evaporation 10.1, evaporation 10.2, default HP Michel
Created attachment 422 [details] Gamma spectrum Photon Evaporation in Geant4 10.1
Created attachment 423 [details] Gamma spectrum Photon Evaporation in Geant4 10.2.p02
Created attachment 424 [details] Gamma spectrum without Photon Evaporation in Geant4 10.1 and 10.2.p02
Hi Michel, on top of 10.3ref01 I have tried to study Gd158 decays using rdecay01 example and macro: /control/verbose 2 /run/verbose 1 # /gun/particle ion #/gun/ion 64 158 64 79.5128 /gun/ion 64 158 64 261.4568 # /tracking/verbose 2 /run/beamOn 1 # /control/cout/ignoreThreadsExcept 0 /tracking/verbose 0 /run/printProgress 100000 # /run/beamOn 1000000 here 1st or 2nd excitations are used as initial state. The results for decay channels are following: 1) Gd158: 1000000 Emean = 0.1881 eV ( 0.02148 eV --> 0.2962 eV ) e-: 857369 Emean = 58.36 keV ( 29.27 keV --> 79.13 keV) gamma: 142631 Emean = 79.51 keV ( 79.51 keV --> 79.51 keV) 2) Gd158: 1000000 Emean = 0.4112 eV ( 0.0001455 eV --> 1.971 eV ) Gd158[79.513]: 1000000 Emean = 0.2233 eV ( 0.1125 eV --> 0.7429 eV ) e-: 1093886 Emean = 77.3 keV ( 29.27 keV --> 181.6 keV) gamma: 906114 Emean = 165.8 keV ( 79.51 keV --> 181.9 keV) do you see any problem with these results? VI
Hello Dorothea, we tried to address all concerns to gamma transition model in the development version of Geant4. The new public release 10.4beta will be available in 2 weeks time. We may backport part of fixes to the new patch to 10.3 but we do not have possibility backport fixes to 10.2 anymore. There were significant changes in all code after 10.2. If you still have interest to the problem you may check 10.3patch01 or 10.4beta. best regards, Vladimir
Hi Vladimir, indeed, in Geant4 10.3.p01 the conversion electrons for Gd look correct with G4LEVELGAMMADATA=/afs/cern.ch/sw/geant4/releases/share/data/PhotonEvaporation4.3.2 Thanks a lot! Which changes will there be for Geant4 10.4.beta? Cheers Dorothea
