-LHCb upgrade II and ALICE3 are not yet baseline. TDR to be written and funding to be finalized. Markus to ask Oliver, we could also ask via the groups and concerning timeline of the TDR. Waiting for the TDR can increase difficulty of studies. In particular ALICE3 has no clear design to reach target performance.
-Preliminary request of at least 2 non-colliding bunches from CMS. A more global answer in ~6months.
-Single beam crabbing option to be studied for November C&S review as a back-up option in case Crab cavities experience delays. Full system in ~1.5 years or in LS4. Baseline is kept with full CC system installed in LS3.
WP3/magnets/FRAS:
-Oscillations of 7 units in the MQXF during the ramp. WP3 will try to improve. To be studied.
-Dipole component from the flux jump in the quads (0.2-0.5 units, likely at 75mm, tbc) needs to be checked as it was not known in the past (quick estimate 1% emittance growth).
-RQX Fault “triggered” on SUB 02 generates 220 ppm field oscillation at (~5kHZ?), however actual field at beam might be only 10 ppm:
https://indico.cern.ch/event/1685331/contributions/7088065/attachments/3343607/5993191/Validation_of_the_HL-LHC_Powering_Performance_in_the_IT_String_Converters.pdf
(performance tbc)
->Ask Arjan for detailed simulations of circuits plus beam-screen? What resources he needs? Experimentally any options? (also with beam in 2030-31 to adapt optics). Guido will perform further mesaurements in the IT string aiming to detect currents to ground, also in the tunnel in LS3?. Role of interconnects Vs core of the magnet.
(more news possibly also in IT string phase II)
-MCBRD08 would need to be fixed only if MBRD6 has poor a2 (larger than 5 units). MBRD6 warm measurements in ~1.5 months.
-Limitations on FRAS (rotation) due to bellows, under discussion.
WP5/ABT/WP4/MP
-TCLIA (and B) are to be removed. ECR to be released.
-Good hierarchy at injection in simulations with phase-knob=1.5. Phase knob at 1 and other configurations will be studied too.
-MP suggests that CC differences of 500kV or 10deg should be interlocked, RF/WP4 must reply about feasibility.
-Halo measurement / simulations are affected by machine non-linearities (beam-beam not yet simulated).
-CLIQ failure: ok with round optics (even with relaxed coll. settings). Optimised phase advance for v1.9 is the key.
-TCLM (mask) temperature: maximum is 55° with the partial jacket coverage, even with flat optics -> it's ok
-lots of work ongoing on the RF side for the longitudinal stability aspects (impedance model improvements, full beam simulations, flat bunch mitigation MDs). They recommend a 800 MHz cavity (only available for Run 5, maybe partial preparations for Run 4, no resources yet).
-IR7 optics: fully validated in MD except for background. We will wait for this feedback to insert this in the baseline, balancing the risk of a new optics.
-removing one collimator because of EWB issues: except for a few specific IR7 collimators, this does not seem to be an issue.
-full detuning scheme -> RF power is not an issue anymore for HL beams
WP13/BI:
-Concerning Schottky issue with high intensity. Studies should follow to clarify the issue. Should we ask BI for an estimate of the time to remove?
-Flexibility in the allocation of the new BPMs DAQ, to be determined with WP13/BI
-Need to check new halo specs document in overleaf.
-New optics requests for IR4 are still possible by the end of the year.
Ions:
-Request of lower beta* in ion optics also for Run 4 ion runs. Stephane is working on a new ATS idea (that could also be useful for protons). This could require large amount of resources.
-Likely CC baseline in ions is for them to remain on. CC noise tolerance to be computed from a 1% luminosity loss.
