LPC meeting summary 17-01-2022 - final
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LPC meeting summary 17-01-2022 - final |
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Main purpose of the meeting: LHC and experimental scheduling for 2022
Introduction (Brian)
cavern closure maintained on March 24.
schedule is tight for LHCb
cavern access still possible in week 13 (to be scheduled timely)
no TS stop foreseen till after summer (one day foreseen beginning of June for injectors, 1 shift for Faser/SND).
possibility of a short stop for cryo filter replacement
during commissioning, some access to detectors possible
900 GeV SB fills are possible in second half of commissioning period
TS scheduled for mid September
afterwards LHCf run and vdM run
LHCb request for extended TS1 to install UT C-side (current estimate: 2 week extension)
4 weeks of ion running (incl. pp ref)
pp reference run before TS2 now excluded
CMS prefers pp at end of HI period; ATLAS prefers at beginning. To be decided later.
HI scheduling during a 4 year run?
EYETS now moved to 24/25.
Maintaining 8w at end of 2025 gives short pp run in 2025.
ALICE prefers early PbPb production:
in 2025: 4w pPb, 4w PbPb
Split HI running over 4 years (4w/year) if no 8w cooldown needed.
Then 15w of pp running in 2025.
To be discussed with LHC.
Special runs:
currently planning for ~ 1 week of special runs/year, not including VdM scans
2025 is a short year, not obvious it makes sense to include special runs as well.
Intensity ramp up:
start with ~ 1.15 10^11 ppb, then fill up ring, then ramp up bunch intensity further
beta* leveling to be deployed from start for validation
not clear if early beta* changes should happen in ADJUST or SB
Action item: Any constraints from experiments for this leveling ??
Q (Trevor): are these still 5% steps?
A (Brian/Michi): yes, every individual step will be ~5%. But they could come fast after each other (e.g. every minute).
So this makes the scenario in the middle of slide 13.
Comment (Trevor): we do have some loss of physics data taking in ADJUST.
Comment (Mario): RPs need to be move out in ADJUST mode
Comment (Federico Ronchetti): ADJUST in middle of fill is problematic. Also safety issue.
Comment (Federico Alessio): same comment: problems for VELO
Q (Filip): any good reason from machine side not to do it in SB? A (Matteo): probably not, but we will have to see.
Comment (Federico Ronchetti): in SB, might be a problem for physics data integrity. Fine if not happens for too long.
Q (Brian): Which lumi jumps are acceptable from ALICE (safety, DAQ, ...)?
non-colliding bunches in IP1/5
single bunches trains at beginning of
at high intensity, these bunches might becone unstable if colliding only in LHCb.
Not possible to lower intensity because they have to match the normal train for validation checks
if needed, can we put these bunches in collision?
- might be possible to have a few non-colliding (but not isolated)
- most likely only an issue for 2023 and onwards
Input from experiments?
Comment from Roderik on HI scheduling:
will be more efficient to have 8 weeks ion run, even if it’s split between 4w pPb and 4wPbPb,
since the lead injection is already set up
Q (Federico R.): need some time to switch proton beam direction.
A (Roderik): yes, about 1 shift or so. Need it in all option.
Round table of experiments
ALICE (Federico R.)
detector closure mid-February.
Global operation starting on Feb 21.
Magnet operation on March 7th.
one module of PHOS calorimeter has leak and needs to be repaired.
tail of cooling works ongoing.
ALICE preference for 4+4+4+4 ion scheme during Run 3, see slide 3.
Prefer to have PbPb data both in 2022 and 2023. pPb in 2024 and again PbPb in 2025.
If 8 weeks of cooldown needed in 2025, still prefer to have PbPb data both in 2022 and 2023.
Then pPb and PbPb in 2025.
8 weeks of HU running will exceed disk buffer capacity foreseen by computing model
ALICE prefers pp ref run after the TS (possibly at beginning)
ALICE pp readout rate: 1 MHz (optimum to be decided)
Q (Brian) in case of your scenario on slide 4: could the pp ref run be moved to 2024?
A (Andrea): would be suboptimal. Ideally have ref. run close to ion run. to cancel some syst. uncert.
So would like similar detector conditions.
LHCb (Federico A.)
RICH2, ECAL, Muon, Plume are installed, commissioning ongoing.
RICH1: installation to be finalized in next weeks
VELO: first half arrival at CERN this month
SciFi: frames 9 & 10
UT:
need 19 days to install and test C-side of UT. Would like to do it in extended TS 2022.
Not having any half installed in 2022 will be detrimental for physics taking in 2023.
So request for a 19 day TS in September.
In 2022, LHCb will not level at more than 1 10^33 .
HI: mild preference for long HI in 2025 due to extra week of pp data.
Particular interest in pPb collisions.
p-He special run: not before 2023 because detector needs to be commissioned
Significant interest in p-O collisions. Later in Run 3 is fine.
VELO recommissioning with 450 GeV beams with few bunches during commissioning period will be very important.
(VELO can only closed after automatic calibration/alignment procedure is completed)
ATLAS (Trevor)
on schedule for closing on March 24th.
extended TS not useful for ATLAS
pp ref run for ATLAS ZDC needs to come before
if pp ref running is at the end, the ZDC migth lose some early beram time due to ZDC commissioning
will be discussed with CMS
HI running in Run 3:
long 8 w PbPb preferred; more efficient, single run benefits data combination, better for cooldown.
oxygen run expected in 2024
Special runs:
- very low mu run (mu ~ 0.005) with 40-50 bunches, 1 fill, during machine intensity ramp-up
Can this be explicitly listed in calendar?
- very high beta* with ALFA for total cross section. As early as possible in 2023 (to minimize rad dam).
- possibly other low/moderate mu runs, likely without impact on others.
CMS (Gianni)
HI preference:
First preference for 8w PbPb run during 2025. Second preference for 4w ions/year.
10 weeks of HL pp running needed before HI run. If shorter, overall schedule needs to be rediscussed.
pp ref run should be close to ion run.
CMS considers very useful to put pp ref run at the end to allow for possibility to use T2 as trigger detector during PbPb collisions
(using T2 as trigger will add redundancy in trigger strategy, also extend physics sensitivity)
LHCf run: CMS lumi group interested to parasitically use the LHCf 2022 test for a VdM length scan.
Which crossing angle will be used?
still under discussion: 2 week period at PU 2-3 in beginning of 2023
remember request of ATLAS for very low PU at beginning of Run 3. Will join this run.
beta* leveling:
prefer ADJUST during beginning.
Prefer 3rd scheme on slide 6.
Comment (Filip): crossing angle for IP1 will be 145 microrad. Not sure what can be done in IP5.
Comment (Michi) : problem with zero angle in CMS and 145 crossing angle in ATLAS is
1) imbalance maybe problem; 2) limited in what you put as filling scheme. Careful with Long Range interactions.
Comment (Brian): keep in mind IP1 will also using offset leveling.
Q (Witold): why does crossing anlge talk to length scale?
TBA
Q (Jamie, FASER): what is the integrated lumi expected between TS1 and TS2 (if extended)
TBA