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LPC meeting summary 27-06-2022 - final

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Minutes and Summary

Main purpose of the meeting: Intensity ramp-up and September VdM and LHCf run planning.

 
LPC Minutes 27.06.2022
 
 
 
1) Introduction (Brian)
 
Slide 3: FASER/SMD emulsion exchange scheduled on 26 july in the morning (to be confirmed in LMC).
 
 
Slide 5: beam-beam MD likely to be postponed to after July 5th.
[Matteo]: current priority to understanding the current injection issues.
Tonight: non-colliding loss maps.
[Roderik]: plan to have XRP settings implemented by tomorrow: if this happens, can do loss maps in collisions tomorrow; if not, later.
 
Slide 10: first 2022 massi files on eos received from CMS. 
Updated scripts for processing them.
Also succesfully copied to NXCALS
Lumi plots now working.
 
 
Next LPC meeting on July 4th at 11:00 (note special time!!)
 
 
2) General Round Table
 
 
CMS (Gaelle)
 
Filling scheme for July 5th confirmed to Single3b_2_2_2. Will stay at 60cm for media event.
[Action LPC: Add the scheme in the filling scheme viewer]
 
Slide 3: CMS needs some time to switch on tracker HV slowly. Different scenarios presented.
Option of having some SB on Sunday (4h) seems feasible. Further discussions with LHC will happen.
Request from ALICE to have the SB during the day on Sunday. Also ATLAS prefers Sunday daytime. No preference for LHCb.
 
In general: CMS prefers scrubbing to be scheduled in blocks.
 
LHCb (Federico)
 
List of achieved commissioning steps on slide 2.
SMOG injection still not in LHCb’s hands
 
Slide 3: plans for first 6.8 TeV fills.
VdM scan at 6.8 TeV during 12b fill.
 
Need to re-commission the leveling application. Would be nice to have it before first 75b fill.
VELO not yet ready to close. Schedule a full VELO safety system matrix test outside of beam.
Start of commissioning of VELO insertion not before 300b. Follow up with MPP to check beam requirements.
 
No need for regular access anymore, will move to punctual accesses.
 
 
 
3) September VdM + LHCf run planning
 
LHCb (Federico/Vladek Balagura)
 
see slide 4.
 
 
Q (Witek): how long for SMOG to stabilize?
A (Vladek/Federico): 5 minutes, total time needed is 30 min.
 
 
Q (David Stickland): for ghost charge estimation: do you need colliding bunches?
A (Vladek/Federico): no, from empty bunches. But need at least 1 colliding bunch to close VELO.
 
 
ALICE (Martino Gagliardi)
 
slide 2: bunch intensity max 10^11. Crossing angle < 100 murad, for ZDC.
 
Comment from Brian: in 2018, had intensity of 0.9x10^11 and 75 murad crossing angle. Suggest to use the same.
 
 
ATLAS (Witold)
 
 
slide 2: four core elements of ATLAS lumi calibration strategy
 
slide 3: proposed program for sept. 2022
Item C is new wrt. 2018.
Item F: >140 indivs, a few non-colliding required.
 
slide 4: 
Item H: need from colliding indivs
H and I could be in same fill.
 
Slide 5-6: open questions
correction: “with 150 bunches … in both beams": should be "in both planes" (not both beams)
Beam tailoring in injectors needed will in time.
Plans for absolute calibration checks of the DCCT? (LPC to ask BI)
 
Slide 7-8: tentative mapping of ATLAS request on overall LPC plan.
 
Note that “I" needs more than 1200 bunches, not 600.
 
 
Q (Lorenzo, LHCf): e.g. slide 9: LHCf run first time to run together with ZDF, ALFA, AFP, need a few hours of commissioning to 
get it all running together. Can A and B be used for latency scans etc?
A (Witek): not A (no collisions), part of B yes, but it’s physics optics, not VdM optics, will be partly low lumi and partly high lumi (10^33). Not sure it’s a good idea to insert RPs. 
But in garage positions, it could be fine. D and G could also be moved around.
 
Request to LHCf to make their commissioning needs clear within the next 2 weeks.
 
 
CMS (David)
 
 
several detectors new for Run 3 (in particular BCM1F and PLT). No more diamonds. Concur with ATLAS request for no high lumi running before the VdM program.
Time estimates similar to 2018.
 
 
LHCf (Lorenzo)
 
 
slide 3: 3b validation run of 30 min might be sufficient for commissioning (but to be confirmed in the coming weeks).
 
why 2-4 days?  2 x 26h run + machine inefficiency.
 
slide 5: need ~8 hours to remove LHCf (daytime)
 
Comment (Marciej from ARP): ARP planning to go in during LHCf run (still TBC).
Then ARP BBA and loss maps after TS. Details of ARP need to be included in the validation cycle of the VdM.