Optical Photons

Hi All,

I’m newer to geant4.

I have a doubt on some examples simulating optical photons. Several times I read ‘ScintFast’ and ‘ScintSlow’ in the definition of the scintillator material.

What do they mean?

Thanks in advance

These refer to the fast and slow components, risetimes, time constants, etc. of a scintillator. They are valid quantities prior to Geant4 11.0, when a scintillator could have up to two components. For Geant4 and beyond, up to three components are allowed, for example SCINTILLATIONTIMECONSTANT1, SCINTILLATIONTIMECONSTANT2, etc. and other related quantities. These replace the fast and slow components. (The three components 1,2,3 do not have to be in any particlar order of decay constant value.). The Book for Application Developers for Geant4 11.0 has a lot more information: (go to “Scintillation” section)


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