2023 Operation

[dukwon]

Full 2023 schedule: https://edms.cern.ch/document/2785501

We are mid-way through the "hardware recommissioning" stage after YETS. This week have been powering tests, handshake tests, beam mode tests etc.

From next week, you can follow along with the commissioning spreadsheet linked at the top of the LPC page: https://lpc.web.cern.ch/

This year the plan is 49 days of commissioning and intensity ramp, 97 days of pp physics from mid-May, 27 days of PbPb physics from late September.

Next YETS will start at the end of October due to the energy crisis.

Lumi targets are anywhere from 60 to 80 /fb for IP1&5, 7 /fb for IP8, 30 /pb for IP2.

[jmc2000]

153rd LHCC Meeting - OPEN Session
https://indico.cern.ch/event/1254283/

Page 14 of the Status of Accelerator document shows 1.3fb/day for 2023, if I understand things correctly, an improvement from 1.1fb/day for 2022. I was under the impression that it was around 0.8fb/day in 2022.

Jmc

[dukwon]

One of the new collimation crystals (installed at point 7 during YETS) is stuck in the beampipe. This will add a ~week delay to first beams.

Caverns are still closing today. Injection tests scheduled for Friday.

[dukwon]

Beam 1 threaded to IP5 before LBDS problems

Beam 2 successfully circulating

[dukwon]

Both beams

[dukwon]

FIrst ramp of the year

[dukwon]

First collisions in 2023 with 450 GeV beams

[dukwon]

https://home.cern/news/news/accelerator ... m-back-lhc

[M.]

First collisions at low-beta* - 1.2m.

Followed by the first beta* levelling with colliding beams from 1.2m down to 30cm in ATLAS and CMS.

[M.]

First Stable Beams @ 1.2m -> 30cm!

Now for the intensity ramp-up...

[dukwon]

On Sunday night the LHC experienced an electrical perturbation, causing an RF trip (P4) and several magnet quenches close to P8. As a consequence, the pressure in the insulation vacuum increased, which indicates a possible leak (unsure if it is air or Helium).

[dukwon]

Rather than doing my own write-up: here's an official one

https://home.cern/news/news/accelerator ... leak-major

[dukwon]

Vibration tests have shown an "a clear anomaly" at a particular interconnect, which is likely where the leak is. X-rays were performed at that location but were inconclusive.
The current plan is to open up the W-bellow at that location on Monday and see what's there.

The longer-term plan will depend on what's found. Coarsely: the repair may or may not require warming up the whole of sector 78. Warming up takes some weeks, cooling down takes about a month, then there's QA, powering tests and training.

Since YETS is meant to start at the end of October, I'm not super optimistic about getting beams back this year.

[dukwon]

Screenshot from 2023-07-24 19-06-09.png (12.88 KiB) Viewed 966 times

This sounds promising and suggests that they might not have to warm up the sector, but we will hear more in the next few days.

[dukwon]

The leak was indeed found on Monday (1.6 mm hole just about visible in the close-up pic below).
Work is ongoing to replace the damaged bellow. Time is really critical, as the longer this intervention takes, the bigger the risk of damage to the cryo system. If it takes too long, the whole sector will be warmed up and we will not have beam again this year.

The optimistic scenario is to have beams back by early September, recommission with protons, then set up the ion run as planned.