E-/e+ pair production test

Physics Processes, Models and Cross Sections
1

Hi all,
I am trying to simulate the e+/e- pair production when an electron beam hits a thin solid foil. I am using Pol01 example. However, the electrons scatter at forward angles only. I need to detect electrons at 45, 60 degrees. I tried the following:

  1. I changed the physics list from Polarized to standard.
  2. I replaced the particle gun to General Particle Source.
  3. I used SetUserLimits() inside the solid target and chose nm.
    However, nothing seemed to make electron scatter at backward angles. The only way to get angular distribution is to increase the target thickness by ten times. But I want to keep the original thickness that was used during the experiment.

Any ideas?

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_Geant4 Version:10.6
_Operating System:Mac OS