Accelerator Report: Protons Are Heading Towards the LHC

Why It Matters

Scrubbing and the collimator repair are essential to achieve the ultra‑high vacuum and protection standards needed for high‑luminosity collisions, directly influencing the LHC’s scientific output and the upcoming HL‑LHC upgrade.

Key Takeaways

• SPS scrubbing run begins, conditioning for 288‑bunch beams.
• Vacuum leak at Point 2 required collimator replacement.
• First LHC beam injection postponed to 27 February.
• Nine‑day commissioning will finalize optics and protection systems.
• Preparations support HL‑LHC upgrades and Run 3 completion.

Pulse Analysis

The SPS scrubbing run represents a critical conditioning phase for the LHC injector chain. By circulating low‑intensity beams, the machine removes adsorbed gases and mitigates electron‑cloud formation, a phenomenon that can degrade vacuum quality and limit beam intensity. For the upcoming LHC Injectors Upgrade, the target is to sustain 288 bunches at 2.3×10¹¹ protons each, a benchmark that depends on a clean, stable vacuum environment.

A vacuum leak discovered in a tertiary collimator at Point 2 highlighted the fragility of the LHC’s ultra‑high‑vacuum infrastructure. The leak, traced to an edge‑welded bellow, required the removal and replacement of both horizontal and vertical collimators, extending the shutdown until 26 February. This coordinated effort involved vacuum, collimation, transport, instrumentation, and cryogenics teams, underscoring CERN’s ability to manage complex interventions without compromising long‑term performance goals.

With beam injection now slated for 27 February, the LHC will enter a nine‑day commissioning window that focuses on orbit correction, optics verification, collimator alignment, and machine‑protection checks. Successful completion will not only resume Run 3 physics but also lay the groundwork for the High‑Luminosity LHC era, where increased collision rates demand impeccable beam quality and reliability. These commissioning steps are therefore both a short‑term operational necessity and a strategic investment in the collider’s future scientific reach.