2023-07-28 12:24:33
The Large Hadron Collider (LHC), CERN’s largest particle accelerator, has been shut down for more than ten days due to a small hole measuring one square millimeter in one of its tubes. An electrical disturbance on the Swiss grid is the cause of this incident.
A tree that fell on a high voltage line in the Morges region created a mini disturbance on the network. If there was no impact for households, CERN’s largest particle accelerator did feel it.
He is so sensitive that following this small incident, his security system was triggered. The liquid helium contained in one of its tubes is therefore no longer cooled.
When it heats up, helium becomes a gas. “And by becoming a gas, it expands. And since it is in an enclosure and cannot escape very quickly, there is a pressure which is exerted”, explains in the 12:30 of the RTS Jörg Wenninger, physicist in charge of the operation of the LHC at CERN.
Also questioned in the 12:45 p.m., he specifies that a “very small hole of one square millimeter opened when there was this great pressure”.
>> Listen to Gabriela Cabré’s explanations at 12:30 p.m.: An electrical disturbance on the Swiss network caused the major outage at CERN / 12:30 p.m. / 2 min. / today at 12:34
Complex repair
In 15 years, never has a repair given the experts so much trouble. If small failures are common, it is rarer to have such large ones.
The small hole “caused a series of magnets, which are essential for the operation of the accelerator”, explains Jörg Wenninger. “Even if there is still perfectly intact circumference, it must be stopped and repaired exactly this component”, he continues.
And this time, shutting down the system takes time. It was first necessary to identify where this hole was and the repair is now very technical.
“You just have to cut the piece, take it out and put the new one on,” explains the physicist. “The problem is that it’s in a complex environment. There are lots of different tubes that obviously must not be damaged”.
Shorter stop
This repair will take several weeks. We will therefore have to wait until at least the beginning of September before being able to restart the first beams, which will have an impact on research. “We are going to lose regarding half of the data expected for this year”, estimates Jörg Wenninger.
CERN accelerators are shut down each year during the winter. Because of this failure, the duration of the next breaks may well be shorter.
“As the failure occurred quite early in the operating period, we can perhaps compensate by operating longer in certain other years”, confirms Jörg Wenninger.
>> Read once more: CERN particle accelerators gently wake up to be operational at the end of the month
Radio subject: Gabriela Cabré
Subject TV: Jacqueline Pirszel
Web adaptation: Emilie Deletroz
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