Minutes and Summary
Main purpose of the meeting:
2022 LHC schedule (mainly short term), beam spot length, PbPb energy proposal.
Minutes LPC Meeting 19.09.2022
1) Introduction (Brian)
RF conditioning faster than expected. Beam commissioning starting tonight or tomorrow.
Run will stop 2 weeks earlier (November 28th). Two options for the remaining 10 weeks are still on the table:
Option A: advance ion run by 1 week and postpone the pp reference run to 2023.
Option B: no ion run in 2022.
In both options, the LHCf run is maintained this week and the high beta* (90m) run is moved to 2023.
Short term schedule on slide 5.
Witold: ALTAS NL scan now moved to beginning of LHCf run.
Also, in JW’s schedule there is a hIgh current running before CT fill: not ideal (tile activation).
Better after 150b run.
Mario: When is RP alignment for TOTEM (low beta)?
Matteo: now in week 39. Exact date to be discussed offline (Mario not available on 25-27)
Federico Alessio: when is ramp-up exactly?
A: Thu/Fri next week. CT is hopefully part of ramp up.
LHCb considering the partial insertion during ramp-up (provided good data during LHCf run).
Special run planning on slide 6-7
Preference from OP and CMS (David) to use VdM indivs for LHCf run. They are quite wide, but should be ok.
Witold hoping that for the real VdM period, the emittance can be improved a bit.
Gianni: how long will 50b fill be?
A: ~ 3h
CT fill: partial separation in IP1 during beta* level … seems ok if not too extreme.
RP’s in ATLAS (and CMS) should go in from the start of the CT fill in order to count for MPP.
VdM programma after TS2: see slide 7.
Potential pp filling schemes after TS1 (slide 8) were studied (see presentation by Lotta in LMC).
Proposal to start with 36b trains and 2461b scheme from August. If option A, stay with this (except for test fills).
If option B: can reconsider 8b4e or mixed for last part of run.
ALTAS noticed OP1 beam spot shorter than expected. Also seems 6% smaller than IP5.
Possible explanations: expt. error? vertical beam size in IP1 15% smaller than horizontal in IP5? crossing angle 8% larger in IP1 than IP5?
Last 2 options would affect IP1/5 luminosity ratio.
Beam energy for ion run. Need to settle soon (if option A, ion run is only 6 weeks away). Training quenches still a concern for 2022.
2-3 quenches could lead to a loss up to 6% in physics times (assuming 3x8h recovery time).
Running tat 6.8Z TeV gives 3-4% more luminosity, assuming the same availability.
Propose to use 6.8Z TeV as baseline.
Final decision in LPC meeting next week if option A is chosen.
Next meeting: Monday Sept 26th.
2) Round Table
ALICE (Sarah)
ALICE will switch to ++ polarity and stay like that for the remaining pp time
LHCf run: alice will take data with whole detector and ZDC. Request is to have overall crossing angle < 100ur, ideally 70 ur (Matteo will check). Check BRAN positions for ZDC shadowing.
After LHCf run, ALICE will resume 500 kHz data taking and the weekly 2 to 5 MHz interaction rates stress tests
LHCb (Federico)
1) During the LHCf run, LHCb plans to conclude the fine time alignment of *all* sub-detectors.
2) VELO should be ready to first close in the ramp-up fills just after the LHCf run.
Proposed to go to 5mm instead of 10mm.
Working hours much preferred, if not to be discussed with VELO team.
We shall plan that the first closure will be done in two steps in the ramp-up (12b, 300b) as indicated by MPP
3) Full VELO closure will be done as soon as analysis of alignment and metrology is concluded.
Dedicate one full day with 12b, 300b and 1200b fills as indicated by MPP • Timescale ~week after first closure, to be driven by VELO team and schedule
4) Week 44-45 (depending on schedule) for VdM are both a good target for LHCb
5) LHCb plans to inject SMOG (like in Run2) in some fills in the next weeks.
Do we still need to inform the LHC about it? A(Matteo): yes
Short summary of LHCf installation. Half day delay (remote control), but successful installation. Max dose received is 30 microSv,
Cabling: completed. Preparation of racks in ATLAS USA15 counting room ongoing. Pictures on slide 3/4.
ATLAS (Joerg)
ZDC detector installed, signals to LHCf have been checked.
Will use collisions on Tue/Wed for timing in.
ATLAS detector in low mu setting.
AFP and ALFA RP settings have been sent by Maciej to Stefano yesterday.
ALFA: protection from accidentally moving the broken ALFA station still under discussion.
Maciej: doing tests with CCC (exclude pots from system) and in discussion with Stefano.
Raised issue of 8b4e or mixed scheme with detector sub-systems and physics coordination. Impact being investigated.
Toroid ramp after muon-alighment run takes a bit more than 3 hours
Could the inter-fill between 1200b and 2400b fill be 4 hours? Try to schedule something?
CMS (Gaelle)
Magnet went down to 2T for safety (sensors that measure helium level checked)
Also identified water leak in EE. Cooling line closed.
CMS back in operation (magnet 3.8T) since yesterday evening.
Successful cosmic data taking last night.
