Resonant Compton scattering associated with pair creation
  Studies of Compton scattering by relativistic electrons in a strong magnetic field have been restricted to either incident photon angles $\theta'$ aligned along the magnetic field $B$ or incident photon energies $\omega'$ below the first pair creation threshold $\omega'_{PC}$. When these restrictions are relaxed there is a resonance in Compton scattering associated with pair creation (PC), that is analogous to but independent of known resonances associated with gyromagnetic absorption (GA). As with the GA resonances, that may be labeled by the Landau quantum numbers of the relevant states, there is a sequence of PC resonances where the scattering cross section diverges. In this paper, the lowest divergence is studied for incident photon energies satisfying ${\omega'}^2\sin^2\theta'/(2eB)\ll1$, assuming that the scattering electron is in its ground (Landau) state. This lowest resonance affects only parallel-polarized photons. 
Jeanette I Weise
astro-ph.HE