Problem 2293

Summary: Something wrong in angular distribution of photoelectron from a polarized beam
Product: Geant4 Reporter: zhangjin <zhangj>
Component: processes/electromagnetic/lowenergyAssignee: Daren Sawkey <daren.sawkey>
Status: RESOLVED FIXED    
Severity: normal CC: daren.sawkey, Vladimir.Ivantchenko
Priority: P4    
Version: 10.3   
Hardware: PC   
OS: Linux   

Description zhangjin 2020-11-23 03:02:45 CET 
According to the physics manual and also after checking the source code of G4PhotoElectricAngularGeneratorPolarized, which gives the angular distribution of G4LivermorePolarizedPhotoElectric, it looks like the these two functions: DSigmaKshellGavrila1959() and DSigmaL1shellGavrila() are identical.
But according to the reference paper: M. Gavrila, Phys.Rev, 1961, the differential cross section for L1 should be: d_sigma_L1 = 1/8 * screening_correction * d_sigma_K. This 1/8*screening_correction factors are missing in the G4 calculation.
Comment 1 Sebastien Incerti 2020-11-23 08:50:02 CET 
Reassigned.
Comment 2 Vladimir.Ivantchenko 2022-10-29 13:16:30 CEST 
Dear Koichi,

please, assign this problem to Daren Sawkey.
Comment 3 Daren Sawkey 2022-12-12 15:35:40 CET 
The factor of 1/8 is added to Geant4 version 11.1 release. This agrees with the original Gavrila paper.