World’s largest atom smasher collides protons and oxygen for the first time in history
The world’s largest atom smasher has conducted its first-ever collisions between protons and oxygen ions, as part of an ambitious campaign to include a series of historic firsts, among which proton–oxygen, oxygen–oxygen, and neon–neon collisions.
CERN’s Large Hadron Collider (LHC), located near Geneva, Switzerland, is the only machine on Earth that’s powerful enough to accelerate particles close to the speed of light and smash them together in controlled conditions.
Now in the opening days of its latest experiment, which began on June 29 and runs through July 9, the world’s largest and most powerful particle accelerator has entered a special phase of operations.
The schedule includes two days of proton-to-oxygen ion collisions, two days of oxygen-to-oxygen collisions and one day of neon-to-neon collisions. Several days of machine setup and commissioning are planned between each phase.
A major event
This development is expected to yield valuable new insights into some of the universe’s most fundamental phenomena, including the nature of cosmic rays, the behavior of the strong nuclear force, and the properties of quark–gluon plasma (QGP), which filled the entire universe a few microseconds after the Big Bang.
CERN revealed that the launch of the experimental campaign marks an exciting new chapter in particle physics and the culmination of a years-long preparation process.
Work began in mid-April across CERN’s accelerator complex, although initial feasibility studies for the run date back to 2019. Each accelerator in the chain had to be specially configured to accommodate oxygen and neon ions.
The ions are reportedly first generated in Linac3, then pass through a series of machines, the Low-Energy Ion Ring (LEIR), the Proton Synchrotron (PS), and the Super Proton Synchrotron (SPS), which will also deliver oxygen beams to fixed-target experiments in the North Area, before reaching collision energy in the LHC.
“The current operating mode, in which a beam of protons collides with a beam of oxygen ions, is the most challenging,” Roderik Bruce, an LHC ion specialist, said. “This is because the electromagnetic field inside the accelerator affects protons and oxygen ions differently, due to their different charge-to-mass ratios.”
Testing the technology
Bruce stated that without corrections, the two beams would collide in different places at each turn. To address the issue, engineers are precisely adjusting the beam frequency and momentum to ensure collisions happen at the core of the LHC’s four main experiments: ALICE, ATLAS, CMS, and LHCb.,
However, according to CERN, the LHC’s four main experiments aren’t the only ones participating in this special campaign. The Large Hadron Collider forward (LHCf) experiment, which focuses on studying cosmic rays, plays a key role.
As part of the campaign, the LHCf experiment installed a dedicated detector along the beamline, positioned 459 feet (140 meters) from the ATLAS collision point. This setup is designed to capture small-angle particles produced during the proton–oxygen collisions.
Once that phase is complete, the detector will be removed and replaced with a calorimeter designed to gather additional data during the upcoming oxygen–oxygen and neon–neon collisions.
The initiative also offers a chance to continue testing crystal collimation, a major upgrade to the LHC’s beam management system aimed at reducing ion beam halos, or particles that drift away from the core of the beam.
“The conventional collimation system at the LHC is less efficient with ion beams, so some crystal collimators will be inserted for testing right before the oxygen–oxygen and neon–neon runs begin,” CERN officials concluded in a press release.
Source: Interesting Engineering
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World’s largest atom smasher collides protons and oxygen for the first time in history