Simulation of positron spectra of a hybrid positron source

Abstract

As known, the dipole approximation of channeling radiation (CR) successively overestimates the radiation yield, when the electron-beam energy approaches and exceeds 1 GeV. Consequently, we applied the nondipole approximation to simulate positron production via conversion of CR into e+e−-pairs in the scheme of a so-called hybrid positron source. GEANT4 simulations of positron spectra obtained from an amorphous tungsten converter at irradiation by <100> axial CR generated in tungsten and diamond single crystals are presented. For comparison, we calculated the CR spectra in dipole and nondipole approximation.

New module for channeling radiation simulation in Geant4

“…To simulate in Geant4 any complex structure which implies ChR (e.g. a hybrid positron source), it is necessary to process two steps: (i) separate calculation of ChR by use of an external program [42,43], (ii) importing of the properly normalized ChR spectral distributions into Geant4 primary particle generator as a histogram [44]. Different external program tools for calculation of ChR distributions, channeled particle trajectories, etc.…”