Hello dear experts
I’m trying to simulate plastic scintillator in geant4. I read the documentation about optical process listed in Scintillation. There was a parameter called “resolution scale”, and although i believe i understand the definition, i’m not quite sure which value fits the best for my simulation (i am currently using Resolution scale = 1). Could anyone tell me what i should take into account to choose an appropriate value?
You normally want RESOLUTIONSCALE=1. A gamma ray of a certain energy will produce a number of scintillation photons which varies according to a Gaussian or Poisson distribution. RESOLUTIONSCALE is a multiplier of the standard deviation of that distribution which makes the width smaller or larger. Resolution scale of 0 means no variation (electron of a certain energy will produce the same number of scintillation photons each time) while 1 means that the number of scintillation photons will vary with a standard deviation equal to the mean of the distribution (for a Gaussian).
Thanks for your help!
@John_McFee Does that mean RESOLUTIONSCALE corresponds to the Fano factor for the material? Or is it sqrt(Fano)?
I’ve never seen it described as such in the documentation, but yes it does seem to be the same as sqrt(Fano).
Just to clarify about this for future readers—the Gaussian used has variance equal to the mean, and then stddev = sqrt(mean), as seen here (lines 428 and 429)
-WS
just to clarify about this for future readers—the Gaussian used has variance equal to the mean
Yep, my bad. The variance is equal to the mean, not the standard deviation. It has to be since the Gaussian is the limit of a Poisson for a large mean. I should have proofread my response more carefully. Thanks, @wsetterb .