Voir en


Accelerator Report: The LHC is well ahead of schedule


Almost the whole accelerator complex is now in “physics mode”, routinely delivering the various types of beam to the different physics facilities and experiments. Notably, the intensity ramp-up in the LHC is progressing remarkably well.

In particular, I am happy to start this report with the good news that, thanks to the excellent availability of the accelerator complex and the hard work of the LHC teams and experts, the LHC is now 12 days ahead of schedule, yielding a direct gain of integrated luminosity and thus physics and boding well for the 2024 run.

The first stable beams of 2024 in the LHC were initially scheduled for 8 April, but the teams working on the LHC beam commissioning managed to be ready earlier and declared first stable beams at 18.25 on 5 April, three days ahead of the official schedule. The first stable beams also mark the start of a period of intensity ramp-up interleaved with the completion of the final commissioning steps.

These final steps include the scrubbing of the LHC vacuum chamber to reduce the production of electron clouds that negatively impact the beam quality and put a strain on the cryogenics system. Usually, the scrubbing lasts two days, but this year an extra day was added since a new injection kicker and two TDIS (target dump injection systems) were installed during the YETS (the new TDIS replace the ones at Points 2 and 8 that suffered vacuum leaks in 2023). The scrubbing run was nevertheless completed in only 36 hours, resulting in another gain in the schedule.

The LHC availability during the recent intensity ramp-up was 85%, including stable beams for about 35% of the time, and the experts very efficiently signed off the checklists at each intensity step. This is why we are now about 12 days ahead of schedule, colliding beams of 1200 bunches and already producing a meaningful level of luminosity for physics. The next step is 1800 bunches, which, if all goes well, might be achieved before the end of this week.

On Tuesday, 16 April, at the end of the afternoon, the first 1.5 fb-1 of integrated luminosity was collected. More than 90 fb-1 are expected for 2024. (Image: CERN)

Meanwhile, the injectors are providing the experiment facilities with beams for physics. The PS was the first to routinely provide beams for physics to the East Area, on 22 March, and n_TOF followed suit on 25 March. ISOLDE, located behind the PS Booster, started physics on 8 April. The SPS fixed-target physics in the North Area started on 10 April. On 15 April, the AWAKE facility located behind the SPS started the first of five two-week proton runs scheduled for 2024. The next in line is the Antimatter factory: the AD and ELENA decelerators should start providing the experiments with antiprotons for physics on 22 April.

The 2024 run has been extended by four weeks, until 25 November, for the LHC, and by five weeks, until 2 December, for the injectors. The YETS will start later this year, which will allow more physics to be done in 2024.