LHC@home

Meanwhile the LHC magnets remain at 2K, allowing more time to train the magnets.

From https://home.cern/science/engineering/restarting-lhc-why-13-tev

At LHC beam energies, the electric currents are extremely high, up to 12,000 Amperes, and superconducting cables have to be used. Superconductivity is a low-temperature phenomenon, so the coils have to be kept very cold, just 1.9 degrees above absolute zero to be precise, or about -271°C. Even a tiny amount of energy released into the magnet for any reason can warm the coils up, stopping them from superconducting. When this happens, the current has to be safely extracted in a very short time. This is called a quench, and just one millijoule – the energy deposited by a 1-centime euro coin falling from 5 cm – is enough to provoke one. Magnet protection in case of quenches is a crucial part of the design of the LHC’s magnetic system.

When a new superconducting magnet is qualified for use, it needs to be trained. That involves steadily increasing the current until the magnet quenches, then starting again. At first, the quenches may occur at relatively low current, but over time, as the components of the magnet settle in, the current increases until the magnet can be operated routinely at its nominal current. If a new training cycle is started after an extended period during which the magnet is warm, the magnet usually restarts training at a value that is higher than first quench in the first training cycle but lower than the maximum previously reached. In other words, the magnet’s ‘memory’ is usually less than 100%.

A magnet quench can be observed from the LHC Cryogenics dashboard, where you see the temperature suddenly jumps from 2K to over 3K, and then cools down slowly. Magnet quench is a common problem that can halt LHC operation for many hours :(

Of course there is magnet quench protection system which dumps the electric currents quickly and safely. Due to electromagnetic inductance U=L*di/dt, high voltage will appear as well when a magnet quenches. An electrical breakdown at this critical moment can boil the helium in a very short time, creating a strong explosion. The LHC was hit badly by this accident at run 1 and took 1 year to repair.

It looks like they are indeed training the magnets these days, there are magnet quenches with no beam. Now the LHC is at run 3 and at 13.6 TeV. After the extended repairs and possibly upgrades, maybe the LHC can try 14 TeV next time?

It looks like they are indeed training the magnets these days, there are magnet quenches with no beam.

Possibly, but given the potential side-effects of a quench - remember those magnets scattered around the tunnel after the first startup - I know I would be wary of trying to train to 14TeV current settings before getting 13TeV data in the can. I'm intrigued by the cryptic references to UFOs in that blog post - sounds suspiciously like someone's dropping their spanners on the machine. (Unless that's a dated baguette reference?)

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I'm intrigued by the cryptic references to UFOs in that blog post - sounds suspiciously like someone's dropping their spanners on the machine. (Unless that's a dated baguette reference?)

Large particle accelerators like the Large Hadron Collider (LHC) are extremely sensitive to tiny vibrations. In fact, physicsts have discussed the possibility of detecting gravitational waves using large particle accelerators. The most interesting point is that particle accelerators are not only sensitive to gravitational waves, but also are probably capable of creating artificial gravitational waves! I wonder when will we build the next particle accelerator after the FCC that could enable unimaginable science fields in both cosmology and particle physics.

Anyway, we still don't have the HL-LHC. The most exciting results obtainable by LHC run 3 include:

Either confirm or exclude lepton flavour universality (LFU) anomalies, and further searches on leptoquark models
New experiements FASER and SND
Results from significantly upgraded LHCb and ALICE experiment, like new exotic hardron discoveries and studies on quark–gluon plasma (QGP)
Higher precision experiments and search of rare decay modes may find the first deviations from the SM

I wonder when will we build the next particle accelerator after the FCC that could enable unimaginable science fields in both cosmology and particle physics.
Anyway, we still don't have the HL-LHC. The most exciting results obtainable by LHC run 3 include....

It's a LONG way to FCC.
Meantime

Beam expexted Thursday

(from Vistars)

Some beams without collisions.
Slowly restart (for security reasons)