Minutes and Summary

Main purpose of the meeting: Schedule

LPC minutes 31st March 2025

Present (P = in person): Chris Young (P), Chiara Zampolli (P), Robert Muenzer, Andrej Gorisek (P), Filip Moortgat (P), Giulia Negro (P), Paula Collins (P), Eric Torrence (P), Andrea Massironi, Andres Dellanoy, Dragoslav Lazic, Klaus Monig, Riccardo Longo, Silvia Pisano Stephane Willocq, Witold Kozanecki, Benoit Salvant, Joanna Wanczyk (P), David Stickland, Jorg Wenninger (P), Michi Hostettler, Gerardo Vasquez, Reyes Allemany, Delphine Jacquet, Flavio Pisani, Rosen Matev, Juan Esteban, Matteo Solfaroli Camillocci

Introduction (Chris Young)

Andrej Gorisek: at what time are the first collisions on Wed morning expected?

Chris Young Young/Jorg Wenninger: the time estimate is around 8, surely before the morning meeting.

Jorg Wenninger: for the high intensity test discussion: tomorrow LBOC is more of a kick off discussion, not everybody is at speed. 

Jorg Wenninger: the LMC asked to have a presentation after Easter, but this is not the best option, then it might be shifted to early June due to my availability. This is anyway ok since it is a discussion for what will happen in 12 months from now.

LHCb (Paula Collins)

Paula Collins: access that is on the schedule planned for May 7: will it be maintained so that LHCb can use it to switch to the diesel backup for SciFi.

Jorg: this is the one with cryo configuration, so it depends on the machine progress, and on how long you need the access to be. Is the usual 1 shift (4-5-6 hours) sufficient? 

Paula Collins: it depends on what happens after the shift. If you have scrubbing, it would not be good.

Jorg Wenninger: it is in between the first stable beam fills. The problem is that it is difficult to nail down the cryo configuration now. For sure there will be an access between Tue and Thu that week. 

Paula Collins: the ideal for LHCb would be to have more access and scrubbing after it to reduce completely the risk of not having enough time.

Jorg Wenninger: it is possible. 

Chris Young: how long would the intervention be?

Paula Collins: we’d like to reserve a full day for it for backup, so that if anything goes wrong, we switch back to the previous configuration.

Chris Young: let’s try to make it match the cryo reconfiguration.

Paula Collins: the changes in the DIP configuration made it quite a lot of work on the LHCb side. And we’d like to know whether the list of changes in the DIP publication is exhaustive.

Jorg Wenninger: there is nothing else than that, there is no list. Normally when there is a change is because you requested something new. This came in from the side. Nobody knew about it. We made it clear that this is not acceptable and if they have a request from their side, they should  come to us, and we then come to you, so that we can all agree also on when it can be done. To be fair, this was not even needed, nobody needed it. 

Paula Collins: the way the b* was done was adding something in addition so that people can prepare and roll forward to it in the future. This was instead a surprise for us.

Michi Hostettler: I would like to transmit the apologies of the controls colleagues: they got a requirement from the timing team, and they misunderstood that the publication format would be the same, which was in fact not the case since it was changing from lower to upper case. They agree that any change should be made in agreement with us.

Paula Collins: thanks for the support, we try to make this complaint helpful. For the list of changes is maybe my lack of experience, but clicking on the link that was provided brings me to something that I cannot fully understand. I see the names of the datapoints, but I don’t know what they refer to. It would be useful if someone can make the list of changes in an easily understandable way.

Chris Young: surely nobody wanted this to happen. It would be useful if the change is just in the case in “payload” or also the content is different.  

Michi Hostettler: if you look at the cmw gateway change list (see link on s5), you see the datapoints that changed. The best I can give is that the list that is here is really everything, how you use them is another story: this I cannot tell.

Jorg Wenninger: [concerning the BCid in B2 that they see, by -21] depends on how you count it. Where is your absolute reference? You can rotate everything around the beam. How do you define the origin?

Chris Young: but you publish a list of colliding BCids…

Rosen Matev: the reference did not change since the last couple of years, when there was not such an offset.

Jorg Wenninger: we had a 1 bucket offset which we corrected, but this is expected. You now see 21 bunch slots (not buckets), which is huge. We don’t know.

Paula Collins: for now we have a global manual offset.

David Stickland: [via chat] CMS sees correctly bunch one colliding with bunch one, not with -21. So they don’t see the offset.

Jorg Wenninger: for the desqueezed beams during ATLAS/CMS VdMs: we still need the optics. For this week, we start with the standard optics. 

Chris Young: it is being followed up.

Chris Young: can you clarify if you request 2 or 4 hours for the first fill?

Paula Collins: we’d like 4 hours but we can try to fit everything in 2. 

 

ATLAS (Andrej Gorisek)

 

Andrej Gorisek: is TS1 fixed on the schedule.

Chris Young: unless of severe issues, it is.

Jorg Wenninger: the horizontal muons are planned for Tue. I have to check how many bunches we had last time. 

Chris Young: we’ll try to work that out today or tomorrow, so that you can have it before the break. 

Chris Young: could we have it for Easter, if we ran out of things to do?

Jorg Wenninger: technically not complicated, but it is a lot of fine tuning between LHC and ATLAS, so you need someone in the control room of ATLAS, some experts. 

Chiara Zampolli: since splashes were not seen in B2, do you need them?

Andrej Gorisek: yes, we’d like to repeat it as soon as possible.

Jorg Wenninger: can we do it around the stable beam time at injection? then it is easy, since you take the same configuration, and you put the collimations in, so it would be on Wed.

Andrej Gorisek: we need some time to switch between the settings. We’d need 30 minutes between the two activities. 

Jorg Wenninger: maybe we could do it tomorrow after the access, even if the end of the access is unclear, so you need a bit of flexibility.

Chris Young: you don’t need people, right? Just some to be set up for it.

Jorg Wenninger: then I put it in the late afternoon.

Andrej Gorisek: can you inject in other buckets to be sure it is not this the issue?

Jorg Wenninger: agreed.

ALICE (Robert Muenzer)

Chris Young: do you have another (in addition to the one of last week for the muon spectrometer) access planned for tomorrow?

Robert Münzer: yes, some measurements could be down downstairs, but nothing urgent. Tomorrow we’ll focus on the dipole. We might request for the delegation to the RP. 

Robert: the access will start at 8h, right?

Chris Young: the access should start around 8, yes.

Jorg Wenninger: in the cavern, you also are more independent, since you saw no radiation, you can probably be relaxed. We need to synchronize with EPC, in case they switch on the dipole. 

Robert Münzer: we’ll stay in contact tomorrow, but there is no access planned close to the dipole. 

CMS (Filip Moortgat)

Jorg Wenninger: which loss maps for PPS [who claims to be interested in being in for them]?

Filip: those at top energy. They only want to know about the schedule, without bothering. 

Jorg Wenninger: this will happen anyway after the alignment fills, so there is time.

Swapping of the low mu, to put it in one of the 75b step: accepted.