I would like to ask what is the difference between the SetScintillationExcitationRatio(0.5) function in the physics process and the AddConstProperty(“YIELDRATIO”,0.5) function in the material properties
AddConstProperty(“YIELDRATIO”,0.5) sets the ratio of yields of fast/slow components for a scintillation material. SetScintillationExcitationRatio sets a multiplier for YIELDRATIO for a particular particle for each scintillation process. It would be used if different particles produced different fast/slow ratios, like for example protons and electrons in an organic scintillator. These parameters were used prior to Geant4 10.7 and and were acceptable but deprecated for Geant4 10.7.
They are not used in Geant4 11.0.0. The accepted method now is to set all these optical properties in the material properties table. So for example, assuming e- and p particles and two time constants (one fast and one slow, it doesn’t matter which is which) you would set:
MPTScintillator->AddProperty(“ELECTRONSCINTILLATIONYIELD”, particleEnergy, scintYieldElectron);
MPTScintillator->AddProperty(“PROTONSCINTILLATIONYIELD”, particleEnergy, scintYieldProton);
…
MPTScintillator->AddConstProperty(“ELECTRONSCINTILLATIONYIELD1”,0.97); //Relative yield of component 1 for electrons
MPTScintillator->AddConstProperty(“ELECTRONSCINTILLATIONYIELD2”,0.03); //Relative yield of component 2 for electrons
MPTScintillator->AddConstProperty(“PROTONSCINTILLATIONYIELD1”,0.90); //Relative yield of component 1 for protons
MPTScintillator->AddConstProperty(“PROTONSCINTILLATIONYIELD2”,0.10); //Relative yield of component 2 for protons
See the Optical Photon Processes section of Book For Application Developers — Book For Application Developers 11.0 documentation
You can read about the old way of doing it in the Optical Photon Processes section at Book For Application Developers — Book For Application Developers 10.7 documentation
(They call the new way “Enhanced”.)