cross-posted from: https://lemmygrad.ml/post/11138809
Archive link: https://archive.ph/59mVr (Links omitted)
Antimatter is matter’s equal and opposite. If the two meet, they annihilate each other, turning entirely into energy. This makes it incredibly difficult to store or move antimatter.
On 24 March, a team at CERN, the European particle-physics laboratory near Geneva, Switzerland, transported 92 antiprotons in a specially designed bottle that traps the particles using magnetic fields. The bottle travelled on the back of a truck, taking a 30-minute journey around the lab’s site.
The experiment’s ultimate goal is to take the antiparticles to a location free of experimental noise, where antiprotons can be studied with greater precision than is possible in the CERN ‘antimatter factory’ where they are created.
CERN is the only place in the world that produces usable quantities of antiprotons. Many staff members turned out with their mobile-phone cameras to capture the truck as it travelled more than 8 kilometres around the site, reaching a maximum speed of 42 kilometres per hour.
“It is something humanity has never done before, it is historic,” says team member Stefan Ulmer, a physicist at Heinrich Heine University Düsseldorf (HHU) in Germany. “We bought a lot of champagne, and we invited the entire antimatter community to celebrate with us today.”
Antimatter can be used to study other phenomena, such as the structure of radioactive nuclei, or researched itself to unravel some of the Universe’s deepest mysteries. Physicists who created the antimatter factory more than 30 years ago dreamed that someday it might be possible to transport the material, says Christian Smorra, a physicist at the HHU who led the project. “Now it’s finally possible.”
“This is a great technological achievement,” says Tara Shears, a physicist at the University of Liverpool, UK. Antimatter is the most fragile type of matter there is, so storing it, let alone driving it around CERN, is “a technological marvel”, she says.
“I love the idea of CERN becoming the Deliveroo [a food-delivery company] of antimatter,” she adds.
Antimatter Deliveroo
Antiparticles are like their ordinary counterparts, except with their charge and magnetic properties reversed. Although matter is abundant, antimatter occurs naturally only very rarely. No one knows why this disparity exists, when both should have been created in equal amounts during the Big Bang.
CERN makes antimatter by colliding beams of protons into a dense metal, then using electric and magnetic fields to slow and capture the antiprotons that emerge. Most particles are lost in the painstaking process.
To develop a portable trap for the particles in which they never touch the matter-containing sides, scientists had to power a superconducting magnet system and use cryogenics to cool it to a chilly −269 °C. The bottle had to be kept in a high vacuum to stop antimatter from meeting any stray matter particles and being annihilated on the way; all the kit had to withstand the forces of the journey in a truck. The team installed a detector, which meant they could check on the antiprotons from the driving seat.
A single gram of antimatter would cost trillions of dollars to make, and its annihilation would release as much energy as a nuclear bomb. But on the basis of CERN’s current rate of production, it would take ten times the age of the Universe to accumulate that much, says Ulmer.
The next phase for the project, known as BASE-STEP, will probably involve delivering the precious cargo to another building at CERN, where the team can practise decanting the antiprotons into another trap, says Smorra.
After that, the team plans to transport the antiprotons around 700 kilometres to Düsseldorf, where the HHU team will use a new experimental lab, now under construction, to study it in around 2029. To measure the mass of the antiproton with extreme precision, physicists must measure its activity in a magnetic field, but the antimatter factory is full of fluctuating magnetic noise. Moving to a new location could improve the precision of measurements by 10 to 1,000 times, says Ulmer.
“For the BASE collaboration, today is really the starting point for entirely new types of experiments,” he says.
“Antimatter’s behaviour is such a mystery that any new information would be really welcome to us,” says Shears. And differences between the behaviour of antimatter and matter “could help us to understand how and why our Universe evolved and looks the way it does”, she says.
“It’s one of the most fundamental mysteries in our subject, and I hope precise measurements on CERN antimatter samples can give us new clues,” she adds.
