LHC portal

The LHC is currently in "machine checkout": the machine and caverns are closed, all interlocks are cleared, and the beam dump system is armed.

Over the weekend we will have some machine protection tests and short transfer line tests.

Monday 18th Oct should see some beam mode tests (NB: no actual beams).

First beams in the ring since 2018 are scheduled for Tuesday 19th Oct, pending the success of the tests at the weekend. By Wednesday we should have circulating beams.

<incoherent excited noises>

~1 day delay over the weekend due to an issue with a UPS (exploded battery).

BIS and LBDS tests took place on Sunday. A vacuum valve controller caused issues and needed replacing.

One klystron on beam 1 needs replacing (takes weeks) but beam tests can go ahead without it.

Today, following some interventions this morning, the accelerator mode should go to "Beam Setup", and the checkout will continue, including transfer line tests.

Tomorrow we should hopefully have beam threading, working up to a first turn, and the following night some "splashes" for the experiments.

Beam 2 has been threaded through the full ring and made >25 full turns in one of the first attempts. Enough to register as a little blip on Page1

B1 was struggling a bit with high losses, but now it has made an appreciable number of turns (small blue blip!)

One probe in B2 now circulating stably

So far so good ! Thanks for keeping us updated. Can’t wait to see the big beast back in business.

Beam Dump

LBDS B1 In fault
no beam for a hour a least
https://vistar-capture.web.cern.ch/vist ... 5566609957

First colliding single bunches at 450 GeV in 'adjust' at all IPs! First stable beams scheduled for tomorrow

Now stable beams!

Aperture scans found a "unidentified lying object" (ULO) at 21L3. A bump of a few mm is sufficient to clear it with no problem.
This mirrors the 2015 post-LS1 commissioning, where a ULO was found at 15R8, which turned out to be a piece of plastic

Highlights from the beam tests:

• High machine availability throughout the tests (~90%)
• 40 hours of stable beams over 5 nights (6 hours planned)
• All key instruments working, mostly from day 1
• ULO found at 21L3
• Opportunistic ramp to 3.5 TeV with pilot beams

The "ULO" has been identified as a buckled RF finger, so sector 23 will be warmed up for an intervention. This delays the restart by several weeks. (However, better to catch it now than then!)

Frustrating to hear the news, but I've been wondering what was going on.
Thanks for the update.