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LPC meeting summary 18-07-2022 - final

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Minutes and Summary

Main purpose of the meeting: Experiment requests/plans for ramp-up period & Planning for special runs after September TS

 

Minutes of LPC meeting 18.07.2022

 
 
1) Introduction (Brian)
 
Topics of the day: Experiment requests/plans for ramp-up period & Planning for special runs after September TS
 
Remaining experiment requests:
 
Beam-beam measurements at injection energy: 
- Proposed program should take 1-2 shifts 
- Need 0.5-1 shift before for validating phase knob: currently scheduled for tomorrow 
- Measurement later this week: currently scheduled on Thursday
 
Scrubbing completed last night.
 
Slide 6: Collinearity scan done last night.
 
Plan for the coming weeks on slide 8.
Slide 8: 2nd 600b fill: beta* leveling is ok during first 4 hours, afterwards keep fixed.
AFP and PPS expressed no preference on the beta* value. Action item: confirm this.
 
MPP prefers the first 4h head-on.
 
Slide 10: AGK setting needs to be changed to final value before the >1500b filling schemes can be uploaded.
 
Slightly adjusted plan for VdM/LHCf programme, see slide 12.
 
Next LPC meeting on August 1st.
 
 
 
2) Round Table
 
ALTAS (Joerg)
 
Slide 2: for AFP run: prefer filling scheme with 48 bpi.
 
Proposal to have both AFP and PPS run during very long 2nd 600b fill (14h). Then 3rd fill can focus on 96pbi (e-cloud effects expected).
 
ALICE (Federico)
 
Slide 2: good progress, following machine ramp-up.
Would like to do a first 500 kHz exercise tonight.
 
Slide 3: ALICE observes displaced vertex. Not so in other experiments. 0.5 mm displaced in x, y. 3mm displacement in z. Cross check done.
Action item: request that machine cross checks this.
 
 
 
Q (Gaelle): is this new? Also in 900 GeV fills?
A (Federico): yes, also in first fills.
 
 
 
CMS (Alessandro)
 
which energy for PbPb? 
 
Comment (Roderick): crystal collimators look fine so far … hope to have conclusions soon.
Action item: LPC to follow up.
 
BB MD phase knob test at injection: which accelerator mode?
Matteo: preference?
A: preference not to switch to MD
 
 
Beam-beam effect at CMS during ATLAS scan (David S.)
 
Feedback from this morning:
 
Slide 2: red circles: when ATLAS scan was happening.
Slide 3: witness effect
Slide 4: shows effects of the ATLAS scan. Problematic to estimate the BB parameter.
Summary: clear observation of BB effect on witness IP during scan of opposite IP.
Statistically significant. Also ATLAS observes similar effect, but online stat. precision is not optimal.
In future, to coordinate with BSRT and wirescanner DAQ.
Promising to perform during a future BSRT calibration scan.