Emission Characteristics of Spontaneous Fission

[mksharma_iitk]

Geant4 Version: 11.4
Operating System: MacOS
CMake Version:4.1.2

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Hi Everyone,

Background: I modified example rdecay02 to tag spontaneous fission emission characteristics. Major changes made were to the Target in DetectorConstruction, making it Galactic, to register each emitted particle from Cf-252 decay. I also set /process/had/rdm/nucleusLimits 252 252 98 98to only limit the decay to Cf-252.

Result/Conundrum: While the neutron multiplicity output by Geant4 for 1E5 events (3.78=11776/(1E5-96889) makes sense (see output below), the gamma multiplicity is 10.65 (=33120/(1E5-96889)). I am baffled as I was anticipating it to be ~8.0 as per this and this publications.

What am I missing? Is it the low-energy threshold which is overestimating the multiplicity?

[jrellin]

I suspect that there are some not so obvious contributions from de-excitation x-rays that are being jointly counted here. IIRC atomic de-excitation is part of EM physics and not rdecay libraries so even restricting the nucleus limits will not prevent them.

As far as I know fission is still not a creator process but you can get much closer with:

G4Track* track = step->GetTrack();
G4bool isCfParent = (track->GetParentID() == 1);

if ((track->GetDefinition() == G4Gamma::Definition()) && isCfParent){
    // Increment your counter
}

[mksharma_iitk]

Thanks, @jrellin! This worked. I in fact went ahead and even compared the emission probabilities with multiplicity and found an excellent agreement with the literature. Just wanted to report the success for future readers and close this topic.