Simulated configuration where the problem arose: we defined a monodirectional and monochromatic photon beam (100 keV) with normal incidence on an iron plate. We were interested in verifying the spatial distribution (behind the plate) of singularly Rayleigh-scattered photons. We observed that the photons that undergo Rayleigh effect in the plate and are afterwards counted behind the plate don't fit the shape of the theoretical Rayleigh differential-in-angle cross section. The number of Rayleigh-scattered photons is too high at small angle values. The problem could come from the value of the form factor used when the momentum transfer parameter x is below 1e5 cm-1 (the first non-zero value in the tabulated data). There seems to be a discontinuity in the obtained photon flux profile corresponding to x=1e5 cm-1. The problem has been observed for other energies (for example 1 MeV). We are a research team at INSA-Lyon scientific and technical university and we develop a simulation code devoted to x-ray imaging techniques. We use GEANT4 to verify our results and to assess the role of scattering in the x-ray image formation process. If you consider that you will need all the information concerning our simulation, please tell us and we will provide all the details. Thank you very much. Nicolas Freud and Simona Pistrui
Dear Dr. Pistrui and Dr. Freud, we would very much appreciate if you could provide us detailed information on your simulation, that would greatly help us investigating your problem. I will assign this problem report to one of our developers (F. Longo), expert in the domain of angular distribution of photon processes; he will take care of it, and may contact you in the next days. Best regards, Maria Grazia Pia
The solution of the problem could take more study on the angular distribution.
The problem requires a careful study of the angular distribution.
The problem has been solved by G.Depaola with a correct method to sample the form factor.
