Minutes and Summary

Main purpose of the meeting: 2024 Planning and Commissioning Plans

LPC minutes 18th March

Introduction (Federico Alessio)

(Catrin Bernius) It was asked how choosing the 3b or 4b affect the 15h required by MPP. We do the long run with one of these or the other, we don't need to do both.

(Catrin Bernius) ATLAS would prefer the 4b scheme.

(Catrin Bernius, Federico Alessio) When we have an INDIV request once a week do we have to lose 141 bunches to use the 1400 bunch scheme listed. The scheme listed was designed for the 2400 bunch step in the intensity ramp up. This will give us a measurement for the cryo. If we are able to remove the steering batches then it may be possible to get 48 more bunches. Even removing the steering trains it is unlikely we can fit another batch due to the non-colliding bunches but this will be checked. With the INDIVs we still have more bunches than the INDIVs scheme from last year, although the difference is slightly larger.

(Matteo Solfaroli Camillocci) There was no decision on Friday at the meeting of the directorate on the shifting of the YETS and it isn't known when the decision will be made.

(Gianni Masetti) CMS would also prefer the 4b scheme.

FASER (Jamie Boyd)

(Roderik Bruce) The limit is actually a little higher but for the study it was reduced to be conservative and for losses before collisions.

(Roderik Bruce, Michi Hostettler) It should be possible with 3 bunches to get 3_1_1 as a filling scheme such that all experiments get collisions.

(Matteo Solfaroli Camillocci) It was clarified that this 3h gives one point and not the full scan. If the rate is better than expected then it might be possible to relax the settings in which case the measurement would need to be done again. This is unclear.

(Catrin Bernius) How is AFP affected by this decision? If the background is low then it may be possible to loosen TCL6 which would help AFP. The simulations show that the impact of opening TCL6 is small but last year it was seen that this did have an effect.

(Federico Alessio) Would changing this mean that loss maps have to be repeated and therefore it should be decided before loss maps? It might be possible to qualify the machine with the tightest settings and loosening them would be allowed by MPP.

(Federico Alessio) The hope is then to do this one night over Easter.

CMS (Gianni Masetti)

(Matteo Solfaroli Camillocci, Jorg Wenninger) It would be better to do this 2h of low-mu after the leveling rather than during the leveling where we want to operate in the normal way.

(Witold Kozanecki) Does CMS still request a run with very high mu with very low numbers of bunches. Yes, but this is later in the year, not during the ramp up.

ATLAS (Catrin Bernius)

(Federico Alessio) Does it mean that if the fill is lost before 7 hours we need to start again. Not exactly, the scan which was going on would need to be repeated but these are all much shorter and only total 7 hours. There is also the possibility of moving some of the scans between the 3/4b and 12b fills.

(Witold Kozanecki) The number of colliding bunches is the same in both but is it the frequency that results in the different IBL rates. Yes, this is the case.

(Jorg Wenninger, Roderik Bruce) Are the settings ready for AFP for the loss maps. Some of this needs to be checked and the settings will need to be made during the day.

(Roderik Bruce) Where did the value of sigma come from? Are they from the latest optics? Yes, they are from the latest optics from Stefan.

(Roderik Bruce, Maciej Trzebinski) Is it the physical values or the sigmas that are the same as last year. It is the physical values but the number of sigmas is also similar.

(Federico Alessio) Would the two emmitance scans be in the same fills? No, there will be two pairs of scans within the same lumi step.

(Michi Hostettler) It would be useful to the machine if ATLAS and CMS can agree which fills they will do emmitance scans and do scans with the same number of steps. This can be arranged.

(Witold Kozanecki, Jorg Wenninger) After the VdM is a mini-intensity-ramp-up required. Not normally. ATLAS will have a special run request in that time then, and this was anticipated by the LHC team.

(Jorg Wenninger) Yes, the LHC probably will do a BSRT fill this year.

(Andrea Massironi) The preference is for one but we will discuss it with the experts.

ALICE (Andrea Ferrero)

(Federico Alessio, Michi Hostettler) When you refer to having no program with large losses do you mean loss maps. No, it is mainly TCTS and TDIS losses that we want to avoid. These will produce losses during loss maps. This will be followed up in morning meetings.

LHCb (Elena Dall'Occo)

No questions.

Re-cap (Federico Alessio)
The 4b no long range will be used in the intensity ramp up. In the intial setup fewer bunches will be used. Feedback on another 450 GeV colliding fill at night can be given at the next LPC.