|Message: Re: Nuclear Gamma Emissions||Not Logged In (login)|
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I managed to find a way _to avoid_ the problem I encountered. Let me describe what I observed. I want to simulate cascades of gamma rays emitted following (thermal) neutron capture by Nitrogen-14. (Neutron separation energy of the capture product, Nitrogen-15, is 10.833 MeV.) To simulate the cascades I made two z7.a15 files, one in $G4RADIOACTIVEDATA and the other in $G4LEVELGAMMADATA. The file in the former directory contains the following entries: P 10833.30000 1.000E-15 IT 10833.30000 1.000E+00 The file in the latter directory lists the ENSDF evaluated level and gamma data for 14N(n,gamma) reaction below the 10.833-MeV level, with all the ICCs set to either 1.000e-20 or 0.000e+00. The problem was that relative intensities of the emitted gamma ray after populating the 10.833-MeV state were wrong ON A PC, specifically, a machine with dual AMD Opteron CPUs running x86_64 Fedora Core 5. Setting /gdrm/verbose 3 and observing the outputs, I saw the following line "G4ContinuumGammaDeexcitation::CanDoTransition - Excitation (energy value) ..." on PCs on which I obtained correct results, while on the Opteron PC the following line was displayed: "G4ContinuumGammaDeexcitation::CanDoTransition - CanDo". The former line is displayed if excitation <= _levelManager->MaxLevelEnergy() in source/processes/hadronic/models/de_excitation/photon_evaporation/\ src/G4ContinuumGammaDeexcitation.cc. This implies that on the Opteron machine excitation > _levelManager->MaxLevelEnergy() for some reason. So I added the data for levels above 10.833 MeV, and then I observe the capture gamma rays with correct intensities. By the way, in the discussion following the thread 186 of the "Documentation and Examples" forum, I found that there're three duplicated lines in the original $G4LEVELGAMMADATA/z7.a15 file and reported it to someone, and the person told the duplicated line won't cause any problem. During my experimenting of the original as well as 14N(n,gamma) z7.a15 files, I found that the gamma rays corresponding to the duplicated lines are emitted TWICE AS OFTEN AS with only one line. The gamma rays on the duplicated lines correspond to the ones which are marked as "multiply placed" (with either `@' or `&') in the ENSDF "adopted levels and gammas" data. Yours, Kazuyoshi
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