The two beams circulating in the LHC are currently running with different bunch intensities – an unexpected (but successful) premiere, giving us a good chance to reach last year’s luminosity record

On 6 October, the total integrated luminosity passed the symbolic mark of 100 fb⁻¹, exceeding the forecast curve. This allowed the bunch intensity to be increased to explore the intensity reach and limitations in view of the HL-LHC era

As the 2025 LHC run enters its final ten weeks, strong performance pushes luminosity past 90 inverse femtobarns, while lead-ion preparations are ahead of schedule

The LHC pre-injectors delivered excellent availability throughout recent weeks, while an SPS electrical fault and an LHC collimator vacuum leak have been overcome, allowing a successful return to full luminosity production

The past weeks brought a mix of hands-on interventions and forward-looking studies across the CERN accelerator complex, while the LHC continued to catch up with the forecast luminosity curve

So far the summer run has seen solid progress in luminosity production, but also some unexpected beam and machine behaviour. Careful monitoring revealed a hardware issue, now being closely watched as the LHC continues to perform at full capacity.

Following the successful oxygen and neon ion runs, protons are back in the LHC, delivering luminosity at a high rate and slowly catching up with the forecast production rate. In addition, a slight increase of the bunch intensity is being considered

The proton physics run has now been paused for the first block of machine development studies, a technical stop and short oxygen- and neon-ion physics runs. Protons will be back in the machines on 12 July

Following the achievement of 2460-bunch stable beams on 24 May, the accelerator complex experienced an SPS magnet failure, a central timing glitch and a complex-wide power disruption. Yet the LHC remains on track to achieve its 2025 luminosity goal

On 19 May, the LHC reached 1200 bunches per beam, a level that is considered meaningful for physics. The full intensity of 2460 bunches per beam could be achieved before the end of the week

The LHC operations team and many other experts have been working hard to set up and validate the accelerator for safe beam operation, leading to the first stable beams for physics of 2025 on 5 May

The LHC has restarted and both beams have been circulating in the machine since 8 April, meaning that the start of the LHC beam commissioning during Easter is apparently not a constant of nature