Minutes and Summary

Main purpose of the meeting: Experimental requests during commissioning and ramp up.

 

1) Introduction (Brian)

- LHC status: some delay due to RF system. Beam operations will start after Easter. S45 expected to be ready for beam on April 18th. S23 about 2 weeks later.

- LHC near term planning was shown (slide 4) 

- LPC meetings will become bi-weekly once there is beam in the machine. Next meeting tentatively on April 25th.

- Luminosity projections for computing request (Run 3 and HL-LHC) were presented. Feedback welcome. Changes in Run 3: 4 weeks of Pb-Pb in 2023, 4 weeks of p-Pb in 2024, 4 weeks of PbPb in 2025. Run 4 updated to new schedule. Run 5 updated to new schedule. Also ion running (ALICE 3). There were no objections.

Q(David S.): can beam be ramped to 6.8 TeV with one RF system?

A(Jorg W.): yes, for probe beam. Not for full beam.

Collisions delayed by 3 weeks. Not before May 12th. Splashes can come earlier, as soon as there is beam in the machine. Interleaved operation possible.

 

2) Round Table

A) ALICE (Federico Ronchetti)

Magnets on till OP wants them off.

Ready for TED shots next week. Not TDI shots foreseen.

Magnet scan during 75 bunch step. See slide 3.

High rate scan plans on slide 5. 

Q from Brian: Filling scheme need to be the same?

A:Filling schemes do not need to be the same during the scan.

For magnet scan plans (slide 4), the conditions do need to be the same though. Can change the magnetic field during the fill in SB, if allowed. Not in ADJUST. Need SB. MPP needs to agree. 

Comment from Jorg W.: for MPP, will need to take a fill before to do this ramp during the fill and measure the orbit changes. 

 

B) ATLAS (Jorg S.)

- Toroid magnet test foreseen ~ mid April

- Proposal for non-linearity scans and beam-beam measurements : slide 3

- slide 4: request for a 900GeV shift for non-linearity measurements after the  luminometers have been commissioned in the first two 900 GeV shifts and separate from the final validation shift just before 13.6 TeV.

Second part of b-b MD requested: extra 4-8h with different configuration.

Comment from Jorg W.: you probably underestimate the timing. Probably needs another shift to prepare for the measurements.

Final part of b-b MD: to be decided after analysis of 900GeV fill.

- slide 4: very low mu run. Check MB modelling for PU simulation. Also early tracking studies.

New: requires isolated bunches, trains not an option.

New suggestion to use part of 3b/12b. Consider just adding a four hours to this run?

 

 

C) CMS (Gaelle)

Currently taking cosmics with magnet on.

For 900 GeV: still ask for 2 shifts for general commissioning.

Non-linearity studies: proposal 1 shift shared ATLAS/CMS. 4-6h for colliding beams. Bit extra for non-colliding. CMS prefers non-colliding everywhere. Needs explanation.

Combi B-B verifications: extra shift under discussion.

Background studies during loss map studies. Either during MD or parasitically.

Comment from Jorg W.: for B-B: need to write down what needs to be measured. Complete formalities as if it were an MD.

Details in slide 7.

 

D) LHCb: no news.

 

3) Summary of Experimental request for early beam (Brian)

 

slide 3: Dedicated TDI shots for LHCb no longer needed (they automatically get it during scrubbing)

slide 4: horizontal muons for ATLAS: follow up with Jorg/Roderik on how to blow up the beam with ADT.

slide 4: beam based alignment of AFP/TOTEM: to be done before loss maps, not during.

PPS  (not TOTEM) needs few hours of data taking at beta*=30cm and 60cm.

slide 5: SB @ 900 GeV: magnet on in all expts (except for LHCb if VELO is not yet fully installed)

slide 8: Roman Pots will go in from first fill?

slide 8: emittance scan can happen head-on everywhere.