Dear colleagues,
I have a minor question about simulation configuration. The DepositionGeant4 module has a parameter “beam_size”, which refers to the width of Gaussian beam profile mentioned in user manual. But I’m a little confused about description.
For simple 2-D Gaussian distribution, the pdf is
assuming sigma_x = sigma_y = sigma, the pdf in polar coordinate is
What is the relationship between sigma and “width” in manual?
Best,
Wei Tong
)
Hello @WeiTong ,
using the parameter beam_size we directly set the source position for Geant4 via the command G4SPSPosDistribution::SetBeamSigmaInR (command see here) . In Geant4, this command again is used as the width of the two gaussian distributions (see around line 285 here). I would assume that this directly refers to the sigma in your equation. If in doubt, please refer to the documentation of the G4RandGauss class.
Does this answer your question?
Cheers
Paul