October 2021 Beam Tests + 2021/22 YETS

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October 2021 Beam Tests + 2021/22 YETS

Post by dukwon » Fri Oct 15, 2021 7:53 pm

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.
Last edited by dukwon on Tue Feb 01, 2022 1:22 pm, edited 1 time in total.

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DCWhitworth
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Re: October 2021 Beam Tests

Post by DCWhitworth » Fri Oct 15, 2021 9:21 pm

<incoherent excited noises>
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Re: October 2021 Beam Tests

Post by dukwon » Mon Oct 18, 2021 10:48 am

~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.

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Re: October 2021 Beam Tests

Post by dukwon » Tue Oct 19, 2021 2:13 pm

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
lhc1.png

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CharmQuark
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Re: October 2021 Beam Tests

Post by CharmQuark » Tue Oct 19, 2021 3:26 pm

:happy-wavemulticolor: :happy-cheerleaderkid: :happy-jumpeveryone: :happy-cheerleadersmileyguy: :happy-cheerleadersmileygirl:
Anyone who doesn't take truth seriously in small matters cannot be trusted with large ones either by Albert Einstein.

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Re: October 2021 Beam Tests

Post by dukwon » Tue Oct 19, 2021 4:00 pm

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
lhc1.png

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Re: October 2021 Beam Tests

Post by DCWhitworth » Tue Oct 19, 2021 4:46 pm

So far so good ! Thanks for keeping us updated. Can’t wait to see the big beast back in business.
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Re: October 2021 Beam Tests

Post by 123e443 » Sat Oct 23, 2021 7:18 pm

Beam Dump

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Re: October 2021 Beam Tests

Post by 123e443 » Sat Oct 23, 2021 7:26 pm

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

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Re: October 2021 Beam Tests

Post by dukwon » Tue Oct 26, 2021 11:50 am

First colliding single bunches at 450 GeV in 'adjust' at all IPs! First stable beams scheduled for tomorrow
lhc1.png

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Re: October 2021 Beam Tests

Post by dukwon » Wed Oct 27, 2021 8:08 am

Now stable beams!
lhc1(2).png

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Re: October 2021 Beam Tests

Post by dukwon » Tue Nov 02, 2021 1:14 pm

Aperture scans found a "unidentified lying object" (ULO) at 21L3. A bump of a few mm is sufficient to clear it with no problem.
ulo_2.jpg
ulo_2.jpg (40.19 KiB) Viewed 21711 times
This mirrors the 2015 post-LS1 commissioning, where a ULO was found at 15R8, which turned out to be a piece of plastic

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Re: October 2021 Beam Tests

Post by dukwon » Tue Nov 02, 2021 1:52 pm

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

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Re: October 2021 Beam Tests

Post by dukwon » Tue Nov 09, 2021 1:07 pm

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!)

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Re: October 2021 Beam Tests

Post by Tau » Thu Nov 11, 2021 9:53 pm

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

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