Minutes of the ICE section
74th meeting on Wednesday 23/01/2013 (08:40-10:30, 6/2-004)
ICE members: Benoit Salvant (BS), Carlo Zannini (CZ), Danilo Banfi (DB), Hugo Alistair Day (HD), Elias Metral (EM), Elena Wildner (EW), Frank Schmidt (FS), Giovanni Iadarola (GI), Giovanni Rumolo (GR), Jean-Luc Nougaret (JLN), 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: BS, CZ, DB, HD, EM, EW, FS, GI, GR, JLN, KL, NB, NM, OB, SP, SRF, TP, WH, XB, Alessandro Vivoli, Alexander Molodozhentsev (from KEK), Alexej Grudiev, Alexey Burov (from FNAL), Andy Butterworth, Bettina Mikulec, Cedric Hernalsteens, Chandrashekhara Bhat (from FNAL), Christian Carli, Christine Vollinger, Daniel Valuch, Daniel Wollmann, Eirini Koukovini Platia, Elena Shaposhnikova, Fanouria Antoniou, Frank Zimmermann, Fritz Caspers, Gabriel Mueller, Gerad Tranquille, Gersende Prior, Giulia Papotti, Giuliano Franchetti (from GSI), Georges Trad, Hannes Bartosik, Harry Renshall, Haryo Sumowidagdo, Helmut Burkhardt, Humberto Maury Cuna, Javier Fernando Cardona, Ji Qiang (from LBNL), John Jowett, Kazuhito Ohmi (from KEK), Lajos Bojtar, Massimo Giovannozzi, Mathilde Favier, Michel Martini, Miriam Fiterrer, Octavio Dominguez Sanchez de la Blanca, Rama Calaga, Raymond Veness, Raymond Wasef, Riccardo de Maria, Roderik Bruce, Rogelio Tomas, Sandra Aumon, Simon White, Tatiana Libera Rijoff, Theodoros Argyropoulos, Tom Mertens, Uli Wienands (from SLAC), Valeri Lebedev (from FNAL), Vittorio Vaccaro (from Naples), Wolfgang Hofle, William Andreazza, Yannis Papaphilippou, Yuri Alexahin (from FNAL).
1) Newcomers / visitors
- CZ started as Fellow on 01/01/2013.
- KL will start as LD on 01/02/2013 and Daria Astapovych as oPAC fellow for HL-LHC on 01/02/2013.
2) Comments on theprevious meetings + Actions
3) General infos
- Brief discussion about starting time for ICE meeting => Do we start at 09:00 (instead of 08:40)?
- SL meeting:
- Summer student project proposals for 2013 => Email sent: Submit your request electronically and send the proposals to Delphine before Monday 04/02.
- Participants to the Advanced CAS in Norway in August: WH, GR and TP (as teachers) + 2 possible participants: Giovanni Iadarola and Adrian Oeftiger (as discussed last year). Any other request?
- List of travel plans for 2013?
- Several MDs taking place these days with several people from the section.
- Ecloud studies for 5 ns suggested recently by SF => 2 scenarios to be compared:
1) 25 ns, trains of 72, nominal spacing between trains, 2.2E11, 2.5 microns,
2) 5 ns, trains of 72*5, nominal spacing between trains, 0.45E11, 2.5 microns.
=> Follow-up by GR and ecloud team to see if this is worth continuing in this direction. The idea from SF is to minimise the volumic pile up density, in particular in the transverse plane at low beta*. Many unknowns in this scenario => As mentioned by SF, the first obvious show-stopper to look at is e-cloud and then (possibly) image current, then LR beam-beam, etc with then obvious strong benefits on single bunch collective effects (IBS, heating due to broad band impedance, head-on bb tune spread, landau damping ...) since the plan is to work at constant current (and constant or slightly lower emittance), which means reduced brillance by big factor.
- LIU SPS Orbit Correction Review (16/01/13).
- LIU-SPS Beam Scraping System Review (22/01/13).
- Possible workshop on impedance in 2014 (Spring => Should be a good time because we need a first estimate of the HL-LHC impedance by November this year) => I propose that Benoit and Nicolas (and those who wants to join) start to think about it.
4) Review of the 2012 activities and current plan for the 2013 ones for BB (WH): pdf
- 2012 => Many activities and good results:
- Scaling laws for LR effects (intensity, number of encounters, separation) checked => Good confidence.
- Reached up to ~ 70 events per collision.
- 25 ns beam already tested.
- Proposed leveling with betastar (first promising tests).
- Instabilities studies / follow-ups, loss of Landau damping, etc.
- Tools developped.
- Studies of the effect of octupoles on chromaticities.
- Preparation of BB2013 workshop.
- Reminder from 2010 that few bunches were lost few minutes after VdM scans => Solved by getting rid of the tune split.
- 2013:
- BB2013 workshop, CERN, 18-22/03/13.
- Analyses of 2012 data + improve simulation tools.
- Prepare for LHC restart after LS1 => Flat-beam is a possible interesting scenario, study leveling scenarios with OP / experiments, etc.
- EM reminded that there are at the moment 2 big unknown mechanisms in the LHC: 1) transverse coherent instability at the end of the squeeze and 2) transverse emittance BU in both beams (mainly H) of ~ 50%. One mechanism which is proposed, which could be in agreement with and which could potentially explain all the observations, is the "3-beam instability" (i.e. the 2 counter-rotating proton beams + e-cloud) proposed by AlexeyB before Christmas => To be followed-up, continuing also to think to other possibilities with for instance the damper noise or other mechanisms (XB, NM...).
5) Review of the 2012 activities and current plan for the 2013 ones for BB studies for HL-LHC and LHeC (TP): pdf
- 2012:
- All the BB studies performed on LHC last year were of great important for HL-LHC.
- Task 2.5 organization with A. Valishev.
- HL-LHC workshop in Frascati => Possible leveling scenarios.
- Fellow D. Banfi, EPFL@CERN started on 01/11/12 to work on DA studies and Sixtrack BB lense studies.
- Another Fellow position was open to work on noise studies => Still to be filled.
- Some studies for LHeC.
- 2013:
- D. Banfi: DA studies, Sixtrack BB lense studies.
- T. Pieloni: DA studies HL-LHC parameter space, strong-strong effects, analysis of LHC data relevant for HL-LHC, modeling of luminosity.
- Fill the 2nd fellow position (EPFL@CERN) on noise studies => Work in collaboration with RHIC and LBNL.
- Collaboration with J. Qiang, S. Parret at LBNL (Noise studies: transverse damper and BB, crab cavities; B. Muratori at Daresbury (Sixtrack development BB 3D new algorithm studies), S. White at BNL (BB and impedance studies + e-lense compensation studies), S. Valishev at Tevatron (Luminosity modeling and benchmark of FMA to DA studies).
- Some studies for LHeC (tune spread and noise effect => Changes in the BB codes will be needed).
- Comment from AlexeyB: in every strong-strong simulations the transverse damper should be included. Discussion about the modelling of the transverse damper => K. Li will present in a future meeting his work and implementation of the transverse damper in HEADTAIL.
- EM's comment: with all the recently studies proposed (LEP3, TLEP...), we can imagine that there will be also some requests for beam-beam (and more generally collective effects) studies... To be followed-up.
6) Review of the 2012 activities and current plan for the 2013 ones for HD (GR): pptx
- HEADTAIL code used over the years on a broad variety of machines and problems, both from ecloud and impedance, both single-bunch first and then coupled-bunch, and both transverse and longitudinal plane.
- 2 versions at the moment:
- HEADTAIL_ecloud (K. Li).
- HEADTAIL_impedance (N. Mounet).
- Many subjects discussed in 2012 and good results:
- Effect of octupoles on ECI.
- Mode analysis for ECI.
- Longitudinal SBI.
- Tracking between impedance/observation points.
- Effect of Q" on SBI.
- ECI with inputs from PyEcloud.
- PWD studies in the PS.
-Longitudinal plane studies.
- Study of the possibility to include BB in HEADTAIL.
- Update on WBF system and HEADTAIL library.
- 2013:
- Several other subjects which are still ongoing: TMCI with 2 RF system, effect of WBF on TMCI, loss of LD, SR + SC to be included/studies for CLIC DR, SI excitation with the FB to reproduce / better understand the past SPS studies, understanding of the LHC instability at injection on 1st batch during scrubbing run which required to considerably increase the octupole's current (factor 4 from the knob), further understand the PSB instability.
- Several identified studies for HEADTAIL-ecloud.
- Several identified studies for HEADTAIL-impedance.
- Work on HEADTAIL-library => Python interfaced library to study collective effects in circular accelerators, with goal st some point to do the great unification between the 2 HEADTAIL (ecloud and impedance) and PyEcloud, and to allow a high level of modularity to be able to add/remove easily any collective effect.
- In summary:
- Plenty of work done/ongoing.
- Issue: lack of manpower to pursue the code development => large scale testing, systematic checks, complete scans etc.
7) Review of the 2012 activities and current plan for the 2013 ones for Imped (BS): pptx
- 2012:
- Many studies and good results for LHC (collimators, Forward detectors, MKI, LHCb VELO, BSRT, VMTSA, LRFF Task Force, e- lens, crab cavities), SPS (HBW kicker, RF cavities, new WS design, pumping ports, UA9, MKE serigraphy), PS (stripline, dummy septum, Finemet cavity, transitions, RF cavities), PSB (injection region, kicker) with many equipments simulated (or started to be simulated) + new theories (finite length, step transition) + new models (longitudinal impedance of the PS, LHC and HL-LHC started) + bench measurements (materials measurement) + beam measurements (with HDWG) in PSB, PS, SPS and LHC.
- Many things went well => Successful application of MM method, material measurement coaxial setup, efficient support to OP, cesuccessful replacement of MKI8D, started to use a procedure for decision to install a new device based on impedance, useful beam measurements taken before LS1, started to study in more depth the PS and PSB impedance, the team took up the responsibility for the heating issues in LHC and SPS, good support from management (new PCs, budget for drills, more CST licenses).
- Issues => Not enough manpower for OP short term issues (essentially only BS and OB from our team, with HD following the MKI, Andriy Nosych from BI and Oleksiy Kononenko at 25%), not enough time for thorough checks before important decisions, still many questions on what happened to the BSRT, not enough effort in PSB and HL-LHC impedance model.
- 2013:
- High priority for HL-LHC with the goal to have an initial estimate of the HL-LHC machine impedance for 01/11/2013 => The plan and repartition of activities has been already discusseed and some new collaborators will even come for 1 month in Spring (U. Niedermayer, GSI, and A. Mostacci, Rome).
- Continue to improve the impedance model in SPS, PS and PSB with several equipments already identified.
- Theory => Elliptical-to-elliptical and elliptical-to-round step transitions.
- Bench and beam-measurements.
- Main deadlines:
- February 2013:
- SPS ZS review,
- studies for LHC forward detectors.
- March 2013:
- PSB injection region,
- new SPS kickers for neutrinos.
- November 2013:
- Report for HL-LHC.
- Anticipate that some deadlines will come soon for MKI, TDI, BSRT, new SPS wirescanner...
- 2 web links:
- cern.ch/imp => http://impedance.web.cern.ch/impedance/.
- cern.ch/wake (NEW!) => https://espace.cern.ch/be-ice-impedance/SitePages/Home.aspx.
8) Actions to be taken for the next meeting
- Old actions.
- New actions:
- Action 1 (everybody): List of (professional) travel plans for 2013 sent to EM before 04/02.
- Action 2 (everybody): Summer student project proposals for 2013 => Submit your request electronically and send the proposals to Delphine before 04/02.
- Action 3 (NM and BS): Start to think / prepare a possible workshop on impedance in 2014 (Spring => Should be a good time because we need a first estimate of the HL-LHC impedance by November this year).
- Action 4 (everybody): Send info to EM about computing resources used (which ones? names? for which code(s)? additional info etc.) and needed in the future.
9) Miscellaneous
- Deadlines and important dates for ICE.
- The next (75th) meeting will take place on 13/02/2013 => Agenda (still tbc):
1) Review of the 2012 activities and current plan for the 2013 ones for SC (FS),
2) Review of the 2012 activities and current plan for the 2013 ones for EC (FZ).
3) Impedance localization update for PS, SPS and LHC (NB).
- See preliminary agendas for the next meetings.
- See List of Actions.
Minutes by E. Metral, 23/01/2013.