Simultaneous injection of electrons and positrons into a magnetic dipole

Magnetized pair plasma consisting of electrons and positrons represents a unique state of matter whose experimental demonstration is still pending. Toward this goal, positrons produced in the NEPOMUC facility at FRM-II near Munich have been drift-injected into the magnetic field of a supported permanent magnet, which is surrounded by a set of electrodes, using a pair of ExB plates. Extensive investigations of the large parameter space consisting of electrostatic and magnetic fields have resulted in injection efficiencies of 100% as well as confinement times exceeding 1 second. In the beam line just upstream of the trap, a compact, low-energy electron gun can be situated to inject electrons parallel to the positron beam, resulting in electron injection into the confinement region using the parameters originally optimized for efficient injection of positrons (as their availability lies many orders of magnitude lower than that of electrons). For diagnostics, both annihilation counts as well as current are measured. The APEX project aims to magnetically confine an electron-positron pair plasma; the mixture of both electrons and positrons is a milestone en route to confining a plasma with a levitated superconducting coil.