Created attachment 705 [details] XTR physics file I suggest some changes for XTR angular distribution simulation (G4VXTRenergyLoss.cc) to be able to produce fine structure of this distribution at small angles. Attached please find corrected version of G4VXTRenergyLoss. Corrections were made in lines 1621, 1603, 1584, 1582, 599, 619. Simulation results before and after correction one can find in our paper [A.A. Savchenko et al 2020 JINST 15 C06024], where we also compared them with experimental data and pure theory. Best regards, Aleksandr Savchenko NRNU MEPhI
Is it possible to send the source code of the test reproducing simulation histo in figs of referenced paper? Thanks.
The angle measurements with resolution ~0.1 mrad require simulation with corresponding angle bins. The analysis was done concerning the selection of bins for angles less than 1 mrad. Numerical integration with 100 angle bins log distributed between 0.3x10^-9 10^-4 shows good agreement with data. The gamma-radiators, however, show less performance at initialization, while transparent one shows additional small peaks. The transparent radiator was updated with Gauss distributed medium thicknesses, G4GaussXTRadiator class. It shows both good performance and agreement with the ATLAS TST data. Additional set/get methods were introduced to the base class for setting the number of bins, min angle2, max angle2, and XTR photon energy range (max/min) The modifications were submitted to G4: git branch xrays-V10-07-07 merge request 2168. It'll appear in the 11 release.
The updated model was integrated into development branch and will be available with the next public release.
