CERN’s breakthrough device slashes cooling time of antimatter by record 99%

Studying antimatter and its fundamental particles could reveal new types of energy sources and many other aspects of the universe that are still unknown to us. 

A groundbreaking study from researchers at CERN (the European Organization for Nuclear Research) reveals a revolutionary device that is capable of cooling antiprotons in a mere eight minutes. It marks an astonishing leap forward from the previous cooling process, which took a grueling 15 hours.

“This considerable improvement makes it possible to measure antiprotons’ properties with unparalleled precision,” the study authors note.

Why cool antiprotons?  

In order to study antimatter, scientists create and collide particles like antiprotons and positrons in a particle accelerator like the Large Hadron Collider (LHC). However, these particles have to be cooled down while they move.

This is because cooler antiprotons move more slowly, making it easier to control them and study their properties with great precision without interference from rapid, random movements. This precision is crucial for accurate experiments and measurements. 

For instance, if you want to find out the magnetic moment of an antiproton, you first need to measure the frequency of spin quantum transitions, also called spin flips.

However, the spin of an antiproton keeps changing between ½ and -½ when exposed to a magnetic field. Therefore, one can only measure the spin-flip frequency when the anti-proton is slow. 

“To get a clear measurement of an antiproton’s spin transitions, we need to cool the particle to less than 200 millikelvins (-459.3°F or -272.95 °C),” said Barbara Latacz, the lead study author and a researcher in the BASE experiment at CERN.

The researchers in the Baryon Antibaryon Symmetry Experiment (BASE) study the magnetic moments of protons and antiprotons to detect any differences between matter and antimatter.

Antiproton cooling through the new device

The BASE team previously developed a setup that took about 15 hours to cool antiprotons. However, “As we need to perform 1000 measurement cycles, it would have taken us three years of non-stop measurements, which would have been unrealistic,” said Latacz.

To overcome this challenge the researchers developed a new device that uses a similar cooling setup but with some modifications.

Initially, antiprotons are slowed down using an Antiproton Decelerator (AD) and Extra Low Energy Antiproton ring (ELENA). In the next step, numerous antiprotons are held in a Penning trap, a device used to confine charged particles (such as ions or antiprotons) using magnetic and electric fields. 

“An antiproton is then extracted into a system made up of two Penning traps. The first trap measures the temperature of the particle. If it is too high, the antiproton is transferred to a second trap to be cooled. The particle then goes back and forth between the two traps until the desired temperature is reached,” the study authors note.

This setup can cool down an antiproton in just eight minutes, meaning that the BASE team can conduct 1000 measurement cycles and get results with precision within a month. The drastic change in cooling is caused by a combination of factors.

For instance, compared to the previous cooling setup, the diameter of the cooling (Penning) trap in the new device is half in size i.e. 3.8 mm. The new device also comes equipped with an advanced electrode system and optimized electronics. 

All these modifications led to better heat management, cut down background noise, and made the setup more efficient. For example, in the previous setup, an antiproton had to stay in the cooling trap for 10 minutes during each measurement cycle, but in the new device, the particle had to spend only five seconds.

Reduced cooling time means improved antimatter analysis

According to NASA, our universe is primarily composed of dark energy (~69 percent) and dark matter (~26 percent). The remaining part is mostly matter (~5 percent) with antimatter forming only a tiny fraction of the universe.  

However, this wasn’t always the case. “The Big Bang should have created equal amounts of matter and antimatter in the early universe. But today, there is not much antimatter to be found. Something must have happened to tip the balance,” a CERN report notes. 

Understanding antimatter in-depth can help explain why it is so scarce in the universe. This is where the new device could make a significant impact. Its ability to rapidly cool antiprotons is crucial for studying antimatter and its fundamental particles with higher accuracy. 

For instance, “Up to now, we have been able to compare the magnetic moments of the antiproton and the proton with a precision of one part per billion. Our new device will allow us to reach a precision of a tenth or even a hundredth of a billionth. The slightest discrepancy could help solve the mystery of the imbalance between matter and antimatter in the Universe,” Stefan Ulmer, one of the study authors, said. 

The study is published in the journal Physical Review Letters.