Take protons for a ride

In this proof-of-principle demonstration, the team loaded around 100 protons into BASE-STEP, a 900-kg Penning-trap system. With the help of two overhead cranes and a trailer, the system was then transported across the hall of the antimatter factory to the loading bay and onto the truck. BASE-STEP features shielding, support structures and transport frames, along with an uninterruptible power supply with two battery units and a liquid helium tank to enable continuous operation of the superconducting magnet system during transport — for up to four hours. Once connected to the power grid, cryogenic temperatures could be maintained using a pulse-tube cooler.

The truck covered a distance of around 3.7 kilometres and reached a maximum velocity of around 42 kilometres per hour. During this drive, Leonhardt and colleagues monitored the performance of the system, including the temperature of the superconducting magnet and the stability of the proton cloud within the trap. After bringing BASE-STEP back to its original location, the team showed that they could separate fractions of the proton cloud and eject them from the trap. This completed the successful demonstration of lossless transport of a trapped proton cloud, representing an important step towards transporting antiprotons to laboratories reachable within a four-hour limit.