Minutes and Summary

Main purpose of the meeting: First discussion on options for the schedule in 2024/2025

Filip (Introduction)

Start of the discussion for the 2024/2025 schedule

• Rende commented that the LS3 would start on the 17th of November. The date is a placeholder but the very final date depends on many inputs still. 

• Jorg commented that regarding the TDIS one has to be a bit careful, as in principle this is not limiting. However, the temperature limitations may still be there. 

  • When injecting high intensity (1.6-1.65) the temperature was rising as high as the dump threshold. This should only limit bunch intensity and not the length of trains. Matteo commented that the probability of a limitation is however low. 

  • To clarify: both sides of both TDIS are being replaced as the lifetime was found to be one year. Rende commented that in point 2, after 67 cycles of the TDI, the bellow gave up.

  • Matteo added that there are studies ongoing to try and limit the operations of the TDIS to try and increase the lifetime of the TDIS. 

 

Jamie commented that there are more than 13 weeks between TSs. Jamie asked if this is expected. 

• Rende commented that this is indeed expected.

 

Silvia commented that the hardware recommissioning seems longer than the initial version.

• Matteo commented that this is what is required at the moment

• However in the 2025 schedule, this is just one week. Rende will take care of uniformizing the schedules.

 

Catrin commented that even 23 days of Ions at good machine availability may not be enough to fulfill the PbPb requirement

• However, there would be a total of 5.5 weeks in PbPb, so in principle this should be taken care of

 

VdM calibration transfer fill during the VdM scan?

• Also there is VdM in PbPb and the pp reference scan

 

Jamie commented that the saving of having a long PbPb period at the end of 2025, would save up ~1 week of set up + TS and the ion ramp-up. 

 

Rende commented that the EYETS was requested by the experiments, mostly for cooling. 

 

MD days are calculated based on the pp days. Since 2025 is longer, then there is also a pro-rata increase in the MDs. 

• Silvia asked if they were needed really? Rende commented that generally MDs are very useful, even at the end of the run.

• Catrin asked why they are so spread out throughout the run. Rende and Michi commented that MDs need to be spread out anyway, but in the schedule they are currently just placeholders. 

 

Georges, Rende and Filip commented on the opportunity of putting the ions at the beginning of the year.

• The cooldown argument stays, there is a huge factor gain (two order of magnitude) especially in the LSS

• One would need to set up all the injectors at the beginning for the year.

• The option 2 also means that there would be no Pb in the North Area 

 

Rende commented that the actual first activity in the tunnel during the LS3 will only happen in March 2026, therefore the need for actual cooldown in 2025 is reduced.

 

Gianni commented that the schedule of 2024 and 2025 may depend on the end date of 2025. Rende commented that the baseline is currently the 17th of November. A small shift could be discussed already now. 

• A possibility of running most in 2026 is not considered and therefore cannot be taken into consideration right now.

• In Q3 of 2024, there will be a complete review of the LS activities and at that moment we will have a much clearer picture. 

 

Stephane Fartouk commented:

• Intensity increase per bunch could profit from a spread of two years rather than one year, to reach a reasonable value by end of 2024

• OO and PbPb have the same cycle, so in principle it would be better to have it in the same year

 

Stephane Willocq asked for the estimated integrated luminosity for the entire Run 3 between the two options. 

• Jorg commented a first simple approximation is simply to scale up the number of protons

• LPC will also fold in the proton per bunch and intensity ramp-ups

 

Gianni (CMS)

• Pp reference run early next year. Around TS1 should be ok

 

Sarah (ALICE)

• The filling scheme for pO and OO is composed of all INDIVs, likely 20 bunches per beam and 12 colliding in all experiments

• Gianni asked what pileup they would use for the pp reference. 3pb-1 is estimated to be 5 days of pp reference after ramp-up 

 

Silvia (ATLAS)

• The HI performance is still a big open question. 

  • Filip commented they are studying and it will be discussed in various performance workshops. All the points are being addressed and looked at.

 

Niels (LHCb)

• ALICE was asked to provide input on the species direction of p, Pb, O.