A Magnetic Field Cloak For Charged Particle Beams

The current design for a proposed Electron Ion Collider (EIC) forsees collisions between hadron and electron beams with a momentum ratio of about 12:1, resulting in a majority of particles produced in the hadron-going region. We aim to analyze these particles' momenta using magnetic fields perpendicular to their trajectories, but as their trajectory nears the beam line such fields would interfere with the incoming particle beams. Here, we demonstrate the potential of a magnetic field cloaking device to passively create a field-free tunnel for the beams while minimizing distortions of the applied external field. Such a magnetic field cloak has been fabricated and experimentally shown to shield more than 99\% of the transverse field at 450 mT.