LHC Report: Beam on

The powering tests described in the last edition of the Bulletin were successfully finished at the end of the first week of March opening the way for 4 TeV operations this year. The beam was back in the machine on Wednesday 14 March. The first collisions at 4 TeV are scheduled for the first week of April.


The first beam of 2012 is dumped after making a few rounds in the LHC.

The magnet powering tests were followed by the machine checkout phase. Here the operations team in collaboration with the equipment groups performs a sequence of tests to ensure the readiness of the LHC for beam. The tests include driving all the LHC systems – beam dump, injection, collimation, RF, power converters, magnet circuits, vacuum, interlocks, controls, timing and synchronization – through the operational cycle. The “checkout phase” is really a massive de-bugging exercise, which is performed with the objective of ensuring the proper functioning of the whole machine and the protection systems.

During the 'checkout phase', work continued in the LHC tunnel during the day. In particular, the vacuum group was preparing for beam the sectors that were opened during the technical stop. The vacuum group finished their work by Friday 9 March and the LHC was closed for full-scale tests over the weekend. These included taking beam down the transfer lines that run from the SPS to the LHC. By the evening of Wednesday 14 March the LHC was in good shape and took beam again. Things went pretty smoothly and circulating beams were rapidly re-established. The RF group worked overnight to time in their system and by the morning both beams were available for optics measurements. The next 3 weeks will be devoted to an intensive (re)-commissioning campaign.  First stable beams at 4 TeV should be declared sometime in the first week of April.

by Rossano Giachino for the LHC Team