BASE-STEP to attempt to move antimatter across several kilometres for the first time
Antimatter is currently believed to be almost identical to ordinary matter, except that the charges and magnetic properties are reversed. But when matter and antimatter come into contact, they annihilate – disappearing in a flash of energetic particles. Scientists today still wonder why our Universe contains far more matter than antimatter, when the Big Bang should have created an equal amount.
To answer this question, CERN is the only place on Earth where physicists make low-energy antiprotons to study in experiments. The BASE experiment, in particular, is one of the six collaborations studying antimatter at CERN, and its aim is to precisely measure the properties of antiprotons. However, the very location of the experiment limits its precision: the particle accelerator and decelerator in the Antimatter Factory generate fluctuations that impact the measurements.
BASE-STEP aims to trap antiprotons inside a special transportable ion trap and load them onto a lorry to transfer them to a facility where scientists can study them with a greater precision. In the longer term, taking the antimatter outside of CERN would allow many other European laboratories to conduct additional independent research with antiprotons.
Images from BASE-STEP’s trial run with protons in October 2024. To download this video, click here.
The first step of the project is to transport antimatter to our dedicated precision laboratories at the Heinrich Heine University (HUU) in Düsseldorf: this will allow us to study antimatter with at least hundred fold improved precision. In the longer term, we want to be capable of transporting antimatter to any laboratory in Europe.
Stefan Ulmer, BASE spokesperson
This technology is completely new, and it is very exciting because it opens the door to new possibilities of study, not only with antiprotons but also with other exotic particles, such as ultra-highly-charged ions.
Christian Smorra, deputy BASE spokesperson
THE BASE-STEP APPARATUS
What is the recipe for transporting antimatter?
An almost one tonne piece of equipment (= transported by crane or forklift). Although it seems like a lot, BASE-STEP is small compared to other Penning-trap experiments. It is designed to fit on a lorry, the frame being narrow enough to fit through ordinary laboratory doors. Most of its weight comes from the superconducting magnets weighing 600 kilogrammes.
A Penning-trap vacuum chamber to hold the particles using magnetic and electric fields.
A persistent superconducting magnet to keep the magnetic field up. Persistent superconducting magnets do not need continuous power input.
Cryogenic cooling with liquid helium, to maintain the superconductivity of the magnets, and the vacuum conditions.
Power reserves, to operate the trap's electrode voltage supplies.
THE CHALLENGES
How do you trap antiparticles that will annihilate if they touch regular matter?
When even air can make your antiparticle disappear, perfect vacuum is the solution: BASE-STEP is a compact, transportable Penning trap that keeps the antiparticles in a near-perfect vacuum thanks to electric and magnetic fields.
Absorbing the bumps of the road: the system is designed to absorb 1 G-force (about 9.8 m/s2) of accelerations in all directions. This is more than enough to absorb the bumps of the road.
Monitoring the antiprotons in real-time: a standard non-destructive image current detection technique is used – this technique is routinely available in precision Penning-trap experiments – so the team gets a continuous signal showing the amount of particles in the trap.
THE STEPS TOWARDS THIS TRANSPORT
How do you prepare for such a feat?
2020: beginning of construction of the BASE-STEP device
October 2024: successful trial run with protons
Up to the end of July 2025: instrumentation upgrade at HHU Düsseldorf
August 2025: move of the upgraded system from Düsseldorf to CERN
September 2025: antiprotons beam taking to fill the trap
OTHER FREQUENTLY ASKED QUESTIONS
Is BASE-STEP the only option for transporting antimatter?
No, PUMA is also preparing a transportable trap. This compact experiment plans to transport antiprotons 600 metres from the Antiproton Decelerator hall to CERN’s ISOLDE facility, where the properties and structure of exotic atomic nuclei will be studied.
What else is BASE-STEP working on?
BASE-STEP is also working on the multiplication and miniaturisation of transportation devices. The idea is to build a more cost-effective machine as a next step.
Is this transportation dangerous? What will happen if the antiparticles annihilate?
BASE-STEP traps between 100 and 1000 antiparticles. If the transportation trial fails, and the antiparticles annihilate, the energy released will be the equivalent of 10 microelectrons of energy (this is the mass of a thousand electrons). By way of comparison, the amount of sunlight that shines onto our skin every second is 1 billion times larger than the amount of energy released by the annihilation of all the antiprotons in the BASE-STEP trap. This transportation is not any more dangerous than any lorry transportation on public roads.
Can antimatter be used as an energy source?
No, the inefficiency of antimatter production is enormous: creation and storage of antimatter take a lot of energy, so you get only a tenth of a billion (10-10) of the invested energy back. If we could assemble all the antimatter ever made at CERN and annihilate it with matter, we would have only enough energy to light a single electric light bulb for a few minutes.
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