A Cryogenic, High-field Trap for Large Positron Plasmas and Cold Beams

摘要

A new Penning-Malmberg trap using a 5 tesla magnetic field and a cryogenic electrode structure (T～10K) has been constructed with the goal of producing large (N ≥10~(10)), high-density positron plasmas and cold positron beams (Δε～ 1 meV). With background pressures ≤ 10~(-11) torr and rotating electric fields to counteract plasma expansion due to background asymmetries, this trap is designed lo be a nearly ideal reservoir of positrons with very long confinement and annihilation times. This paper describes recent experiments using electron plasmas to optimize confinement and plasma compression, and minimizing the diameters of extracted beams. Further, it is shown that this trap will be an excellent device in which to study the physics issues associated with a recently proposed multi-cell trap.