Beams are Back

The Large Hadron Collider has celebrated π day by sending protons round in a giant circle. This marks the start of operations for 2012 with collisions at a new record energy of 8 TeV due in a couple of weeks.

Beam 1 which turns counter-clockwise was successfully sent all the way round the ring a few moments ago. Beam 2 will complete its round tour shortly.

The plan for the next couple of months will no doubt be to get to last years luminosity and beyond as quickly as possible, hoping to produce 5/fb of new data in time for the big ICHEP conference in July.

Update 16-Mar-2012: Two days on and beams have now been ramped to the new energy of 4TeV for the first time, fast work.

2 Responses to Beams are Back

  1. Art says:

    Reading over the LHC news as they get the machine going again it seems as if they are doing it for the first time. Looks like it takes weeks before they start scrubbing. I’m curious why they can’t just save settings and return to the way it was last Nov. Why does it all have to be redone after a stop?

    • Philip Gibbs says:

      If they just closed the machine down and started it up again later with no changes they could probably just about do what you suggest. In reality many things have changed and they need to retune all the settings. The change to 4 TeV will have some effect and (more) so will the different squeeze to 0.6m. Mostly though it will be minute changes caused by all the repairs and adjustments made during the shutdown that could affect the orbit of the beam.

      I think once they get past the initial steps and reach collisions at 4 TeV with all the settings adjusted for the new golden orbit, they should be able to increase the number of bunches and get back to last years luminosity quite quickly. Some amount of caution with qualification stages is to be expected even so.

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