Portable trap carries particles 5000 kilometers

Electrons suspended in a Penning trap were transported more than 5000 km, all the way across the continental United States. The magnetic field was provided by a persistent superconducting solenoid at 4.7 T which was not connected to any source of power during travel. The electric field was produced using ordinary 9 V batteries. A good vacuum, expected to be sufficient to keep antiprotons stored indefinitely, was maintained within the trap by keeping it at 4 K. Portable traps are of interest for experiments which require small numbers of antiprotons for precise studies, for acceleration to energies not available at the LEAR antiproton source, for experiments with large immovable detectors, and for possible medical applications. The portable apparatus is so similar to that used to contain low energy antiprotons, that the trip demonstrates the feasibility of transporting cold antiprotons over large distances in portable traps.