Beta interactions

Beta particles are electrons. As shown in the following plot taken from the review article Passage of Particles Through Matter in PDG, electrons lose their energies in matter primarily through ionizing atoms around them (Geant4 name: eIoni, GEARS process id: 2002) below 10 MeV. More energetic electrons are more likely to generate photons through Bremsstrahlung (Geant4 name: eBrem, GEARS process id: 2003). Multiple scattering with orbiting electrons (Geant4 name: msc, GEARS process id: 2010) is a subdominant way for an electron to lose energy.

The following figure shows a few tens of 2 MeV electrons flying through the air. Green lines are photons generated by some of them through Bremsstrahlung. It is generated by running

$ cd /path/to/gears/tutorials/physics/beta
$ gears air.mac

The contents of the macro file air.mac can be viewed online here.