LPC meeting summary 11-10-2021 - final

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Minutes and Summary

Main purpose of the meeting: 2021 beam test preparation

Status and plans for beam test (Jorg Wenninger)

- caverns closed already on Friday evening 15.10.

- first collissions likely earlier than Thu. probable Tue or Wed (to be confirmed)

Q (Gianni): what will be the machine mode and beam mode
A (Jorg Wenninger): not much constrains. Over the weekend “shutdown, no beam”. From Monday onwards “machine checkout” and at some point switching beam modes. 

Comment (Joerg Stelzer): starting time of meeting on Friday is 9:30.

Beam test requests (Brian):

two topics: 
1) beam test 

A) Splashes
Comment from Jorg: we can deliver splashes @ 1 per minute. We can wait for green light from expts if useful. Bucket 1 is default but can be changed

Q from Federico: how will it happen for LHCb?
Stefano: close the TCTs and steer full pilot beam on TCT’s.
Jorg: there is no dump action. We request that beam ends on collimator. Max 1 shot/minute.
Federico: triggering will be impossible. Maybe remove LHCb from the plan. To be followed up.

Joerg S: how reliable is bunch in bucket 1? Can it be different?
Jorg W: should be reliable. Bucket will be well defined.

Q (Mario — offline): 
Do I understand right that from tomorrow on we have to keep the injection and user permits on TRUE?
We are still chasing an instability in our RP movement/interlock system, but we are able to provide stable permits by going to "holiday mode" (via LVDT bypass like in the past, as discussed with MPP) and switching off the override key. These functionalities have been tested and documented in the collimation elog.
Should we do these key operations tomorrow?
A (Jorg — offline): The user permits should be true from Friday evening onwards. For the injection permit we can agree on the same deadline. So it is fine if you switch the key Friday during the day...

B) collisions

Trevor: is the (0,894, 1785) scheme the same as on the LPC page for 2018
A: yes, should be.

2) detailed schedule for 2022

Q(Trevor): With this draft schedule, how does the integrated lumi look for 2022?
A: Not calculated.

Q(Rende): Should we tentatively schedule VdM in week 27 and the LHCf run in week 40?
A(Brian): To be confirmed.

Q(Brian): Would VdM setup be ready by week 27?
A (Jorg): yes, everything would be commissioned during first 10 weeks.

Q (Witold): in 2018, CMS wanted high L running before VdM. Still true now? 
Any requirements on minimum radiation dose?
A (Gaelle): to be followed up

Comment (Witold): there are benefits to keep VdM and LHCf run close together.

Feedback from experiments:

ATLAS slides (Trevor):

(slide 1-6 skipped)
slide 7:

Q(Brian): for step 3: is 1200 bunches enough?
A(Witold): yes, fine. Better to have it earlier with 1200 bunches than later with 2500.

CMS slides (Gianni)

Gianni: Massi files needed during beam test?
Brian: probably nice to exercise it … but not urgent.
Jorg: not needed from machine side

Request for parasitically running during LHCf run seems possible.