LHC Report: Heading towards the 4 TeV

The giant is waking from its slumbers. For about a week now, protons have been in the injectors: first passing through the LINAC, Booster and PS; and, since last weekend, passing through the SPS. The beam is now knocking at the doors of the LHC.


Only a few weeks ago the CCC looked empty and desolate. It is now crowded with people working indefatigably towards the restart of operation with beam. At the LHC island, people are hard at work to ready the machine for its rendez-vous with the beam now foreseen for 14 March.

After about five weeks of cool-down, all the main magnets are now filled with superfluid helium. Since Thursday 1 March, the cryogenics system has been operating at nominal conditions all over the ring – everything is green on the screens over in the north corner of the control room. Meanwhile, TE-VSC is performing bake-out operations in the vacuum sectors of the injection collimators in order to reestablish the required vacuum conditions following the interventions during the Winter Technical Stop.

The electrical quality assurance has almost been completed on all superconducting circuits and the preparation of all the quench protection systems is well on track. The magnet powering tests (started only three weeks ago) are also progressing well: up to now, more than 90% of the tests with current have been performed successfully. To achieve these results, LHC operators and engineers have been performing tests during evenings and nights to cope with the large amount of interventions that are still keeping a lot of people busy in the tunnel.

Since the announcement at Chamonix, the teams have been preparing the machine for 4 TeV operation. While this implies a minor increase of the current in the main dipoles and quadrupoles, huge attention must be paid in order to qualify the circuits to this new energy level. So far, all efforts have paid off: presently, six of the eight LHC sectors have been brought to the new current levels, and heat runs, with all the circuits powered at these new current levels, have been performed as well.

During the first week of March all powering tests will be completed and the machine check-out will start. The beam is knocking at the door, and the LHC crew will certainly not make it wait.

by Mirko Pojer and Matteo Solfaroli for the LHC team