Status: Large Hadron Collider after injecting Beams 1 & 2 separately

William Atkins
Thursday, 18 September 2008 22:04

Science - Energy

CERN scientists successfully circulated beam one, the clockwise beam, and, thereafter, beam two, the anti-clockwise beam, on Wednesday, September 10, 2008. The following week involved fixing some problems before proceeding with the next stage.


A play-by-play (maybe, more like a "particle-by-particle") account of the Beam 1 event, on September 10, is found on the blog website of Stephanie Majewski, a post-doctorial student in particle physics at Brookhaven National Laboratory in Upton, New York, who is working with the ATLAS experiment at CERN’s LHC.

The successful circulating of beam one and two separately within the LHC is shown in the following CERN highlight (local times listed):

Beam 1

Patrol done by 08h. Getting SPS ready.

08.30 Beam to TEDS both lines. Interleaved injection.
09.00 Switch to beam 1 only. Kickers executing soft start.
09.30 Beam to TDI. Kickers on.
09.40 TDI out. Beam to collimators point 3.
09.45 Collimators IP3 out. Beam to left of point 5.
09.55 Collimators point 5 out, beam ~to point 6 but not to the extraction line.
10.00 Beam to dump block (steered with DC bump). Half way round ring1!
10.08 Beam to collimators in point 7.
10.12 Beam to point 8 collimators.
10.30 Beam round > 1 turn image on screen showing beam on first and second turns trajectory
With a bit of correction - beam makes 3 turns

Beam 2

Switch to beam 2 only.

13.30 onto the TDI
13.40 TDI out, beam to point 3.
Cryogenic instability needs a little more time
13.55 Beam to 6, steered into start of dump line
14.05 Beam to left of 6. Lost. Investigating.
14.25 Problem understood. Beam to right of 5. 20 shots for CMS.
14.40 Beam round to 3 (after one correction in 4). Few corrections needed.
14.45 Beam to ALICE.
14.50 Beam to ATLAS. Few shots for them.
Few minutes no beam. Reboot for screen server.
15.00 Beam > 1 turn

Beam 2 was circulated for over one-half hour and, then, safety extracting from the LHC.

Comments from a CERN news release on the event is found on page two.