BASE experiment takes a big step towards portable antimatter
A team of scientists and engineers have taken an important step towards the goal of being able to store and transport antimatter by transporting a cloud of 70 protons in a truck across CERN’s main site.
At the CERN Antiproton Decelerator(AD), scientists produce and trap antiprotons every day. The BASE experiment, which was part of the AVA project, can even contain them for more than a year. However, transporting the antiprotons to another location has so far eluded them, but this is something that scientists working on the BASE experiment hope to change one day with their subproject BASE-STEP: an apparatus designed to store and transport antimatter.
“If you can do it with protons, it will also work with antiprotons,” said Christian Smorra, the leader of BASE-STEP. “The only difference is that you need a much better vacuum chamber for the antiprotons.” This is the first time that loose particles have been transported in a reusable trap that scientists can then open in a new location and then transfer the contents into another experiment. The end goal is to create an antiproton-delivery service from CERN to experiments located at other laboratories.
The BASE experiment aims to answer the question of why the universe is dominated by matter by precisely measuring the properties of antiprotons, such as their intrinsic magnetic moment, and then comparing these measurements with those taken with protons. However, the precision the experiment can achieve is limited by its location.
“The accelerator equipment in the AD hall generates magnetic field fluctuations that limit how far we can push our precision measurements,” said BASE spokesperson Stefan Ulmer. “If we want to get an even deeper understanding of the fundamental properties of antiprotons, we need to move out.”
This is where BASE-STEP comes in. The goal is to trap antiprotons and then transfer them to a facility where scientists can study them with a greater precision. To be able to do this, they need a device that is small enough to be loaded onto a truck and can resist the vibrations that are inevitable during ground transport. The current apparatus weighs 1000 kilograms and needs two cranes to be lifted out of the experimental hall. Even though it weighs a tonne, BASE-STEP is much more compact than any existing system used to study antimatter. Its footprint is five times smaller than the original BASE experiment and it is narrow enough to fit through ordinary laboratory doors.
During the rehearsal, the scientists used trapped protons as a stand-in for antiprotons, but storing protons as loose particles and then moving them onto a truck is a challenge because any tiny disturbance will draw the un-bonded protons back into an atomic nucleus.
While bumpy roads are problematic Smorra noted that the biggest potential hurdle isn’t currently the bumpiness of the road but traffic jams: “If the transport takes too long, we will run out of helium at some point,” he said. Liquid helium keeps the trap’s superconducting magnet at a temperature below 8.2 Kelvin: its maximum operating temperature.
“Eventually we want to be able to transport antimatter to our dedicated precision laboratories at the Heinrich Heine University in Düsseldorf, which will allow us to study antimatter with at least 100-fold improved precision,” Smorra said. “In the longer term, we want to transport it to any laboratory in Europe.” After this successful test the team plans to refine its procedure with the goal of transporting antimatter next year.
Another experiment, PUMA, is also preparing a transportable trap. Next year, it plans to transport antiprotons 600 metres from the AD hall to CERN’s ISOLDE facility to study the properties and structure of exotic atomic nuclei.
This article is based on an original article published on the CERN website which can be found here
Feature image: The BASE-STEP transportable trap system, lifted by crane through the AD hall before being loaded onto a lorry. The team monitored all the parameters during transport. (Image credit: CERN)