Minutes of the ICE section
86th meeting on Wednesday 03/07/2013 (08:40-10:30, 6/2-004)
ICE members: Adrian Oeftiger (AO), Benoit Salvant (BS), Carlo Zannini (CZ), Danilo Banfi (DB), Daria Astapovych (DA), Elias Metral (EM), Elena Wildner (EW), Frank Schmidt (FS), Giovanni Iadarola (GI), Giovanni Rumolo (GR), Javier Barranco (JB), Kevin Shing Bruce Li (KL), Nicolo Biancacci (NB), Nicolas Mounet (NM), Olav Ejner Berrig (OB), Serena Persichelli (SP), Sergio Rioja Fuentelsaz (SRF), Tatiana Pieloni (TP), Werner Herr (WH), Xavier Buffat (XB).
Present/Excused: AO, BS, CZ, DB, DA, EM, EW, FS, GI, GR, JB, KL, NB, NM, OB, SP, SRF, TP, WH, XB, Berengere Luthi, Guido Sterbini, Andrea Mostacci, Mauro Migliorati, Hannes Bartosik, Simon White, Fritz Caspers.
1) Newcomers / visitors
- Andrea Passarelli (technical student on UA9 simulations and measurements) => With CZ.
- Berengere Luthi (Summer student on ALFA simulations) => With BS (and CZ).
2) Comments on the minutes of the previous 85th meeting + Actions
- No comment.
3) General infos
- No particular comment from anyone.
- SL meeting:
- CERN psychologist => ~ 100 people / year and the majority is between 25 and 35 years old.
- Council approved the MTP.
- Feedback to SL (also discussed during BE workshops): how to get / give feedback between section members and SL.
- Staff promotion => Letter from Paul Collier to each staff member given by the SL (for any step => Was only for the additional steps in the past).
- HD defended his PHD thesis last Thursday => Went very well => Congratulations Hugo!
- BS participated to the BE training for management of projects on 25/06/13 at Java Hill.
- Impedance measurements these days: MKI, TCTP, new RF fingers design, PS septum, etc.
- Talk from NM at 11th WP2 Task Leaders meeting on MO 01/07/013 => Action done.
- Next action for Impedance Team (Action 1 below) => Check the power loss computation in the triplets (with the 2 counter-rotating beams) to be sure that our approach is ~ OK.
- SC meeting last TH and FS is now at GSI.
- BB meeting on FR => Talk by JB Jeanneret.
- Discussion with DanielS and GA about his possible contribution to beam-beam studies => BBLR.
- RLIUP => Will be 29/10/13 to 31/10/13.
- A student from Michael Benedikt could come and help us for the impedance measurements for ~ 10 weeks.
- LBOC restarted yesterday => https://indico.cern.ch/categoryDisplay.py?categId=4991. Several actions for our team => Will come after our internal review in September. Some items:
- 25 ns beam.
- ~ 10% longer luminous region (request form experiments) => However, as mentioned by RogelioT during the meeting, the luminous region will be smaller at 6.5 TeV (with Gianluigi's parameters) compared to 2012 => See for instance the comparision between the 2 cases (blue: 2012 and red: 2015, with the presently assumed parameters).
- Discussion to do some longitudinal bunch flatenning with noise (ElenaS) => Already followed up by WH and beam-beam team as this could be a potential worry.
- Soccer game on Friday (OP vs MD, the revenge...) => Good luck as I will unfortunately not be around!
4) Brief reports of the 4 WGs (by the WG leader or replacement) => Plan, activities, deadlines, issues, etc.:
a) BB (WH):
- BB meetings:
- Dynamic aperture studies with 6D beam-beam lens and small beta* for HL-LHC optics ongoing, try to interprete the findings.
- Presentation at ICE will follow.
- Crab cavities are being implemented into sixtrack.
- Lumi scan for ATLAS:
- Computations (TP) and tools handed over to the experiments.
- Work will be written up in a report.
- Work on COMBI:
- Implementation of effects other than beam-beam is ongoing (XB), benchmarking with other code.
-Improved performance with new strategy for parallelization.
Talk by Jean-Bernard Jeanneret:
- Studied effect of large divergence (small beta*) on beam-beam effects.
- Was found to be small and in the shadow of other effects.
- Not needed to include in the simulations.
b) SC (FS => Given by EM as FS is at GSI):
1) FS has reported on his trip to BNL (talk on the SC web page)
- Newest MAD-X has SC included (collaboration Laurent & Frank). Has been tested.
- MAD-X extreme cleaning demonstrated.
- RHIC was successful run with MAD-X including SC which also includes "real" BB.
- MPI for MAD-X analyzed and promised to be implemented by BNL code experts.
2) Computing power will be investigated with Bernd Panzer (action FS).
3) Crash of PTC-ORBIT verified by Harry Renshall after several days of computing! Debugging started. (action: Raymond, Harry, Frank).
4) Severe PTC-ORBIT physics problems reported by both PSB and SPS team Elena/Vincenzo and Hannes. Needs clarification to proceed any further (action both teams).
5) FS has implemented PTC-ORBIT with MPICH2 on lxplus (including recipe) should be used by all PTC-ORBIT users from now on. Unfortunately does not solve the crash issue.
6) Program of work for all 3 teams expected for next SC meeting by the end of the month July.
c) EC (GR):
- Nothing reported.
d) IMP (BS):
- See slide.
- BS added during the meeting that SP is currently publishing a report about her work on the PSB finemet cavities.
5) Effect of transverse impedance on luminosity measurements (EM): pdf
- Computations to be checked.
- (Very) negligible effect (if no mistake), assuming that the beam is moving essentially at the TCT and that this represents the main impedance contribution (Witold Kozanecki already informed) => Assumption to be checked (Action 2: NM).
6) Actions to be taken for the next meeting
- Old actions.
- New actions:
- Action 1 (Impedance team): Check the power loss computation in the triplets (with the 2 counter-rotating beams) to be sure that our approach is ~ OK.
- Action 2 (NM): Check / follow-up of the impedance contribution to the luminosity measurememts.
7) Miscellaneous
- Deadlines and important dates for ICE.
- The next (87th) meeting will take place on 07/08/2013 => Agenda:
1) Brief reports of the 4 WGs (by the WG leader or replacement) => Plan, activities, deadlines, issues, etc.: BB, SC, EC, IMP.
2) Status of the work for the internal review on the LHC performance limitations during run I (on 25-26/09/2013) => All the speakers.
- See preliminary agendas for the next meetings.
- See List of Actions.
Minutes by E. Metral, 03/07/2013.