Pair creation in heavy ion channeling

Abstract Heavy ions channeled through crystals with multi-GeV kinetic energies can create electron–positron pairs. In the framework of the ion, the energy of virtual photons arising from the periodic crystal potential may exceed the threshold 2 m e c 2 . The repeated periodic collisions with the crystal ions yield high pair production rates. When the virtual photon frequency matches a nuclear transition in the ion, the production rate can be resonantly increased. In this two-step excitation-pair conversion scheme, the excitation rates are coherently enhanced, and scale approximately quadratically with the number of crystal sites along the channel.