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Beams are back in the LHC for the final year of Run II


Frédérick Bordry is Director for Accelerators and Technology

Beams were circulating in the LHC by 30 March (five days in advance!), and everything is looking good for a strong final year of LHC Run II.

Although starting the LHC is becoming routine, it’s always a thrill to see the machine come back to life after the end-of-year technical stop (YETS). There’s always a sense of anticipation as we embark on another year of data taking, on this occasion for the last time before the LHC’s second long shutdown, LS2. This year, the machine has been performing well right from the start. Over the first 10 days, its availability was a very impressive 88%, and we were able to progress faster than the start-up plan had foreseen. By the first week of April, we were working with nominal bunches, and providing beam splashes to the ATLAS and CMS experiments. One week later on 12 April, we had the first test collisions.

Such smooth progress doesn’t do justice to the huge amount of maintenance work carried out during the YETS, and the task of bringing the world’s most complex machine back into action. Before beams get anywhere near the LHC, the upstream accelerator chain has to be recommissioned, from the proton source through Linac 2, the PS Booster and on to the PS and SPS. That process began at the beginning of March. While it was going on, the LHC’s 1560 electrical circuits were gradually powered up, and some 10,000 tests were carried out to ready the machine for beam. It’s a great testimony to the quality and dedication of all the teams needed to run the LHC that so much of this work passes largely unnoticed to many of us as we check the machine’s progress conveyed to us via LHC page 1 online and on screens around the lab. I warmly congratulate them for it.

As I write, we’re well on course to ramp up the beam intensity towards the target of 2556 bunches per beam, passing the threshold of 1200 bunches, which will allow data taking to begin in earnest, by early May. 2018 is an important year for the LHC experiments. It’s the last year of Run II with the ambitious target of recording 60fb-1 of data to bring the Run II total to 150fb-1. May the physics begin!