Why does the ratio of Am-243 alpha-decay not match with that of the IAEA?

[yixiannanmo]

Geant4 Version:11.1.2
Operating System:Ubuntu 22
Compiler/Version:11.4.0
CMake Version: 3.22.1

Problem

The kinetic energy of alpha from Am-243 decay was obtained with geant4 as:
.
The data from IAEA is:

.
And, these two data are inconsistent!

Code

TrackingAction:

void TrackingAction::PreUserTrackingAction(const G4Track *track) {
    // 1. only secondary particle
    if(track->GetParentID() != 1) return;
    // 2. only alpha
    const G4ParticleDefinition* particle = track->GetParticleDefinition();
    // 3. only radio decay
    G4int process_type = track->GetCreatorProcess()->GetProcessSubType();

    // 4. Fill root
    G4AnalysisManager *analysis_manager = G4AnalysisManager::Instance();
    if(process_type == fRadioactiveDecay && particle == G4Alpha::Definition()) {
        G4double kin = track->GetKineticEnergy();
        analysis_manager->FillNtupleDColumn(0, 0, kin / keV);
        analysis_manager->AddNtupleRow(0);
    }
}

How to solve it?
Thank You!
Best!
Kun ZHU

[maire]

Here, a macro for example rdecay01 and its printout.
Am243.mac.txt (390 Bytes)
Am243.out.txt (2.8 KB)

[yixiannanmo]

Dear Michel
The alpha particle of 5275 keV from decay has a probability of 86% in IAEA, which is not consistent with that of Geant4.
Best!
Kun ZHU

[bmorgan]

What is the rest of the code and in particular what are the geometry, materials and primary generator action?

If you build the rdecay01 example with your install of Geant4 and run the script @maire supplied, what plot/ratios do you get?

[maire]

On the printout, you can see 86693 Np[74.664 keV] created for 100000 decays of Am243 —> 86.66 %

[yixiannanmo]

Oh, it’s right in the rdecay01. The physicsList i used based on rdecay02, and Am-243 is a volume source.

[maire]

The full decay chain includes 9 alpha emissions :
Decay chain: Am243 —> Np239[74.664] —> Np239[31.131] —> Np239 —> Pu239[7.861] —> Pu239 —> U235[51.697] —> U235[0.076] —> U235 —> Th231[205.310] —> Th231[185.718] —> Th231 —> Pa231[101.409] —> Pa231[84.215] —> Pa231[58.570] —> Pa231 —> Ac227[29.980] —> Ac227 —> Th227[9.290] —> Th227 —> Ra223[286.087] —> Ra223[50.128] —> Ra223 —> Rn219[158.640] —> Rn219[4.470] —> Rn219 —> Po215[271.228] —> Po215 —> Pb211 —> Bi211 —> Tl207 —> Pb207

you must count only alphas from the first transition Am243 → Np239*