Magnetic Shield Approach Toward Non-adiabatic Low to High Field Positron   Beam Transition for Microtraps
  This simulation study sheds light on effectiveness of a magnetic shield on non-adiabatic transport of a positron beam from 3700G to 100G where we were able to maximize the low to high field transmission efficiency for 6.5KeV positrons. An initially brighter beam can be transported even more efficiently. Cross-sectional uniformity of the beam is also studied for different beam energies. This is important for filling microtraps consist of thousands tubes with diameters of tens of microns each. Transverse momentum of the particles is also studied since it causes mirroring in the high field and compromises efficiency. Beam remoderation is required as ~eV energy positrons will be trapped in the Microtrap. The observed magnetic shield assisted low to high filed transition opens new avenue for high efficiency manipulating of non-neutral beams. 
M. A. Khamehchi, A. Narimannezhad, M. H. Weber, and K. G. Lynn
physics.plasm-ph physics.acc-ph