Activity diagram showing the LHC Beam Modes for the nominal sequence with protons or ions. The diagram presents the standard procedure to run the accelerator through the nominal cycle. Transition details suppressed for clarity.

  • ABORT: Recovery mode following beam permit drop. This mode can be entered from any state if there is no beam in the machine.
  • CYCLING: Pre-cycle before injection following access, recovery, etc. The objective of this mode is to reset the magnetic history of the machine and prepare the machine for a new cycle.
  • RAMPDOWN: Ramp down and cycling after programmed dump at end of physics fill.
  • RECOVERY: Following quench, emergency beam dump, post mortem, etc. Within this mode the reason of the abort, quench, emergency dump, etc, will be diagnosed by the post mortem analysis system.
  • SETUP: Possibly beam in transfer lines with transfer line dumps in. Includes pre-injection plateau and injection plateau - no beam in ring.
  • UNSTABLE: Emergency mode entered from stable beams in case of sudden beam degradation. The UNSTABLE BEAMS mode may be entered without prior warning to the experiments.
  • STABLE: Stable conditions with collisions in the experiments, backgrounds and life time under control. Small adjustment of beam parameters permitted. In case of slow degradation all the experiments are warned and the ADJUST mode is entered when all the experiments have confirmed they are ready.
  • ADJUST: Preparing for collisions or adjusting beams after the squeeze. Possible to enter this mode from STABLE BEAMS. Possible to enter this mode at the end of STABLE BEAMS without the intention of going back into physics.
  • SQUEEZE: Preparing for or squeezing.
  • FLAT: Ramp finished - pre-squeeze checks.
  • RAMP: Ready to ramp or ramping or immediate post ramp.
  • PREP: Injection complete, preparing for ramp.
  • INJECTION PHYSICS: At this stage the machine has been optimized. It proved to be able to have circulating beam with appropriate lifetime and it is ready to accept higher intensities needed for physics.
  • INJECTION SETUP: During the INJECTION PROBE BEAM we will be able to make measurements with very limited precision. In order to make more precise measurements before filling for physics, a SETUP BEAM will be used.
  • INJECTION PROBE: If either ring 1 or ring 2 will be injected with or have safe beam circulating. In this mode a number of checks will be done for the different accelerator sub-systems before injecting higher intensities.
  • INJECT & DUMP: Dump after small number of turns following injection. This mode may be used during first commissioning or for injection studies. In this scenario screens are allowed to be in the beam.
  • CIRC & DUMP: Dump after large number of turns following injection In this mode the screens are not allowed to be in the beam. It will use the timing system to trigger the beam dump via the BIS.
  • BEAM DUMP: Requested or emergency dump. It will be verified that all the machine protection equipment performed correctly, together with the LBDS system via the XPOC analysis.