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LPC meeting summary 25-04-2022 - final

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Minutes and Summary

Main purpose of the meeting: Discuss the latest experiment plans for the beam commissioning and ramp up

 
1) Introduction (B. Petersen) 
 
Run 3 started. Updated 2022 schedule on slide 4. LHCb VELO installation will move by 5 days.
With 3 week delay, FASER/SND emulsion exchange needs to be updated.
 
New LPC website (getting rid of windows-based server, now openshift, should be faster). Links have been updated.
Let us know of any issues or wishes. 
Added list of main commissioning steps for experiments, see slide 6.
 
Requests for splashes have been updated in the past week, see slide 7.
 
Comment from J. Wenninger: CMS splashes straightforward. For the ATLAS ones, need to set up some scraping in SPS. For ALICE, we can go to 10^10, but not above.
For the low intensity ones, would be good to deliver shots to all experiments with the same intensity; then go up in the next step.
ALICE (Federico) agrees. 
 
Comment from R. Bruce: from collimator point of view, not above 10^10.
 
Q (Joerg, ATLAS): what was the intensity of the splashes last Friday?
A (JW): Last Friday, the intensity was 5x10^9.
 
Plan for 3b bunch fills on slide 8.
PU requests from LHCb/ALICE? A: can be head-on.
 
Plan for 12b and 75b fills on slide 9.
ATLAS and CMS are still discussing a combined request for very low mu run.
 
Slide 12: example of VdM period steps. Currently 2018 plan here, should be updated on the request of experiments.
 
Slide 13: massi file exchange system needs to be revived. Want to move from AFS to EOS. Would be good if this could be tested during the  900 GeV run.
 
Upcoming LPC meetings on slide 14.
 
 
Q (Joerg, ATLAS): horizontal muons, in SB? 
A (JW): no, but need some time to set up beams, collimators, etc. So probably before/after the 900 GeV run.
 
Q (David): when do we need to have the documentation for the dedicated beam-beam measurements ready?
A: About two weeks.
ACTION: Documentation proposing beam-beam studies tentatively to be provided by next LPC meeting.
 
 
 
2) Round table
 
CMS (Gianni)
 
First splashes taken last Friday Timing shifted by 5 ns (2 RF buckets).
 
Splashes request from CMS for next Tuesday: ~40 per side with similar intensity as 2021.
 
Q for JW: daily run meeting to move to 8:30? 
A (JW): at the moment stay on ZOOM at 9:00. Will reconsider in a few weeks.
 
 
ALICE (Federico):
 
splash events seen last Friday.
 
Splash request for Tuesday: 20-30 TDI splashes (B1), 20-30 TCT splashes (B2), intensity from LHC program.
 
Q: can JW give the sequence?
A (JW): will send it later today. 
ACTION: JW to send proposed schedule for splashes.
 
Maybe repeat in future with nominals but only on TDI.
Different intensities needed to study the linearity of new BCM system.
 
 
900 GeV collisions: 1 or 2 fills with higher number of bunches (30?) to have from 10 to 20 kHz interaction rate in ALICE. 
Comment from JW: 20 bunches is reasonable, not higher due to zero crossing angle.
 
Q (Brian): other experiments interested in this?
A: Other experiments (LHCb, CMS, ...) are interested, as long as isolated (no trains).
Brian: might be possible to do this in the evening/morning, to be discussed.
 
 
 
LHCb (Federico)
 
 
VELO-A plan to start installing Wed 11 May. Start venting on 10 May. Pump down on 15 May.
Leaves no time for commissioning of A side. Very challenging.
 
Accesses required: 
- VELO, MUON, SCIFI: longer access on 27 April (full shift)???
- VELO: need a follow-up access next week as well (day flexible), full shift?
 
Commissioning with beam:
- test injection with SMOG with LHC: after 27 April; please let us know when is a good moment.
- splashes: like a few for background monitors  
 
Comment from JW: will schedule 1 shift access next week (Tue-Thu)
 
 
 
ATLAS (Jorg)
 
No news this time.