LPC meeting summary 29-11-2021 - final

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Minutes and Summary

Main purpose of the meeting: Follow up from Evian & input for Chamonix.

Introduction (Brian):

Jorg: start of Run 3: not clear yet. Be ready to close on March 24th.
Jorg: 900 GeV beams 4-5 weeks into commissioning (rather than 2 in Brian's slide). That would be easier because the nominal setup will be ready by then.

Gianni: how long does it take to set up 900 GeV collisions?
A: if based on nominal setup: little overhead (<1 shift).

Q (AFP): can roman pots be inserted during 900 GeV collisions
A (Jorg) : prefer not to do this

Action item: are non-colliding bunches still needed?

Gianni: we assumed beta* changes will be in SB. Why Adjust?
Jorg: will be in SB. But if we want to do many steps fast after each other, maybe this is problematic for some experiments. Can this happen in SB? To be discussed.

Round table:

ATLAS (Trevor):

Comment from Jorg: for pp reference run: in 2018 we used a simple setup: combined ramp + squeeze to 3 metres. Then collide. 25ns trains, 1.1 10^11 ppb.
If you want to go lower in beta*, will have to add a squeeze. That would add commissioning time. 
For 2022: probably fine to go down to 2m without extra hassle. Might be able to 1.1 10^11 ppb. So factor 2 higher PU than in 2018 might be possible.

ALICE (Federico):

pref. of having pp ref. run together with HI run after the TS.

CMS (Gianni)

we see that pp ref run before TS is not feasible.
Still considering swapping pp ref run and HI run after the TS.

LHCb (Federico)

LHCb still requests extension of TS1

Need to coordinate a few commissioning session with the LHC
(BCM interlock, VELO closure, PLUME calibration, SMOG2 commissioning)
COVID related travel restrictions are problematic for VELO, RICH and SciFi.

FASER & SND (Jamie)

Request 1 day shift sometime mid-July to install the emulsions. Needs to be a scheduled access.