6th Evian Workshop

Hotel Hilton

Hotel Hilton


The 6th Evian Workshop will be held on 15-17 December 2015 in the Hotel Hilton in EVIAN (74), France.

Attendance is by invitation only.

The principal aims of the workshop are to:

  • review 2015 performance, availability, and operational efficiency. Identify possible areas for improvement;
  • examine beam related limitations and establish a strategy for Run 2;
  • a critical review of system performance;
  • develop an outline of the operational scenario for 2016/Run 2 for input to Chamonix 2016.

Chair Mike LAMONT
Deputy Chairs Malika MEDDAHI
Editors of the Proceedings Brennan GODDARD
Informatics & infrastructure support Hervé MARTINET
Workshop Secretary Sylvia DUBOURG
    • 10:15 AM
      Welcome Coffee
    • Kick-off
      Convener: Mike Lamont (CERN)
    • Availability
      Conveners: Laurette Ponce, Matteo Solfaroli Camillocci
      • 2
        2015 availability analysis
        • Introduction to fault review in 2015 o Weekly fault review, corroboration of data o Reminder on dependencies attributes • Availability charts: o Number of faults/downtime per week (periods of the year, scrubbing, TS,...) o Availability by week • 25 ns run o Downtime chart per system (including faults in the shadow) o Downtime chart with children faults assigned to parents o Downtime chart including turnaround penalty and precycles -> indentification of top 3 contributors to downtime • Availability matrices (frequency+impact by failure mode) for top 3 contributors • Ion run, injection problems • Main problems of the year and worries for 2016; recurring faults in 2015 • Comparison with 2012 • Conclusions
        Speaker: Andrea Apollonio
      • 3
        QPS - operational aspects
        The status of the quench protection system after LS1 is reviewed, between challenges and major faults. The energy extraction issues are also analysed. Attention will then focus on the operational software tools and interfaces. The foreseen major modifications and improvements during YETS will be discussed.
        Speaker: Mirko Pojer
      • 4
        Introduction - cryogenic hardware configuration for Run2 (benefits and limitations of chosen operation scenario, failures and impact on operation) Cryo Maintain availability indicator - statistics (feedback from LS1 maintenance and consolidations, cryogenics vs e-cloud thermal load - retrospect and perspectives) Helium consumption and losses – statistics YETS main activities and 2016 run - proposal of operational scenario
        Speaker: Krzysztof Brodzinski
      • 5
        R2E - is it still an issue?
        R2E and the Mitigation Strategy Radiation levels and comparison with previous run Failure analysis and strategy (Information collection, QPS, EPC, RF, Others, Summary and prevision, TID: long term problem) On-going and future developments (radiation tolerant requirements)
        Speaker: Salvatore Danzeca
      • 6
        RF (hardware)
        The LHC beam intensity increase not only required the system to routinely run close to its maximum performances, but also demanded a very high operational reliability from the entire system. This talk will describe the operation of the LHC RF system during 2015, including new features, operational procedures and the lessons learned.
        Speaker: Olivier Brunner (CERN)
    • 1:00 PM
    • Operations
      Conveners: Giulia Papotti, Jorg Wenninger
    • 4:10 PM
    • Performance and limitations - part I
      Conveners: Belen Maria Salvachua Ferrando, Rogelio Tomas Garcia
      • 12
        LHC Emittance Growth until Stable Beams
        In 2012 emittance calculations from luminosity indicated that about 30 % potential peak performance was lost due to transverse emittance blow-up through the LHC cycle. The origin of the blow-up was only partially understood. The available emittance measurement systems gave inconsistent results. During Long Shutdown 1 the LHC transverse profile monitors underwent important upgrades to improve availability and measurement accuracy. Emittance measurements through the 2015 LHC cycle will be presented. Significant emittance blow-up is still apparent. The majority of the blow-up occurs during the injection plateau and beginning of the energy ramp. IBS is one of the main sources. IBS simulation results will be shown and compared to measurements. In addition strong vertical emittance growth was observed at 450 GeV. The status of the investigations to identify the source of the vertical growth will be given. A first estimate of transverse emittance blow-up of BCMS beams will also be presented.
        Speaker: Maria Kuhn
      • 13
        Luminosity, Emittance Evolution & OP Scans
        During 2015 proton physics operation, beam size estimates were derived from the luminosities acquired during small VdM-like beam separation scans (the so called "OP scans"). This talk recalls the main results from such scans, e.g. fill-by-fill differences and emittance evolution in stable beams. In particular, it is shown that emittance shrinking due to synchrotron light damping was observed for the first time with proton beams. Furthermore, the luminosity evolution is analysed and the optimal fill length is derived based on average and expected turn-around times. A few comments on the luminosity imbalance between ATLAS and CMS and BCMS bunch-by-bunch emittances are also given.
        Speaker: Michi Hostettler
      • 14
        Luminosity modeling for the LHC
        In this talk, a luminosity model based on the three main components of the LHC luminosity degradation (intrabeam scattering, synchrotron radiation and luminosity burn-off), is compared with data from runII. Based on a Fill-by-Fill and a bunch by bunch analysis and observations, other sources of luminosity degradation will be discussed. Finally missing pieces and next steps will be briefly discussed.
        Speaker: Fanouria Antoniou
      • 15
        How to survive a UFO attack
        UFOs in the LHC have proven to be a potential threat to machine availability. While the correlation of peak losses with beam intensity had initially indicated a potential limitation, the fast advance of the conditioning effect appears to have saved the day. In this presentation we will present our current understanding of the UFO threat, the BLM strategy to optimize machine availability and machine protection, and the various lines of attack for UFO-related R&D.
        Speaker: Bernhard Auchmann
      • 16
        LHC aperture and ULO restrictions: are they a possible limitation in 2016?
        Frequent multiple-UFOs events in C15R8 that trigger a beam dump were often observed during the LHC commissioning in April 2015. Detailed local aperture measurements revealed the presence of an unidentified lying object that induces such losses. A quantitative and systematic overview of all the observations and measurements performed in 2015 it is shown. In conclusion the present situation and a possible strategy to deal with this object during 2016 it is discussed. An overview of beam loss behaviour along an LHC cycle it is also given.
        Speaker: Daniele Mirarchi
    • 8:00 PM