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Workshop on Linac Operation with Long Bunch Trains

→ Europe/Berlin
Sem. R. 1, Bldg. 1 (DESY)

Sem. R. 1, Bldg. 1

DESY

Notkestr. 85 22607 Hamburg
John Carwardine (Argonne), Nicholas Walker (DESY), Siegfried Schreiber (DESY)
Description
Large Superconducting linacs such as the European XFEL and the International Linear Collider will operate with long bunch trains and heavily beam-loaded accelerating cavities. This workshop will address the special challenges of operating such machines. A central feature of the program will be results and lessons learnt from the '9mA studies' at FLASH during September 2009, with one goal of the workshop being to develop plans for future studies at FLASH. The 9mA program was initiated jointly by DESY and ILC-GDE in order to achieve the following objectives:
  • Demonstrate bunch-to-bunch beam energy uniformity and pulse to pulse beam energy stability with long pulses at full beam loading
  • Characterise performance limitations at gradients approaching quench, including Control requirements for gradient overhead and RF power overhead
  • Measure cryogenic loads (HOM absorber studies)

WORKSHOP OBJECTIVES

The workshop will address special issues associated with running long bunch trains in the FLASH linac at DESY. Central to the workshop will be the joint DESY-ILC '9mA studies program' and long bunch-train operation for the FLASH photon users. XFEL-related studies at FLASH will also be considered. Goals for the workshop can be broadly summarized as follows:
  1. Review results and lessons learnt from the most recent 9mA studies period in Sept 09.
  2. Explore strategies for efficiently re-establishing stable long bunch-train operation with currents from 1mA to 9mA
  3. Explore strategies for characterizing LLRF stabilization of beam energy at the limits of RF power and cavity gradient
  4. Develop proposals for future studies at FLASH and identify associated preparatory work
The program will include a review of FLASH operation with long bunch-trains for ILC- and XFEL-related accelerator studies and for photon science experiments. A major part of the workshop will be dedicated to working sessions developed around four thematic Working Groups, described below.

Working Groups

A full day of the workshop will be dedicated to working sessions developed around four thematic Working Groups. The working group themes are briefly described below. There will be joint working sessions of the various groups to cover overlapping topics.

Working Group #1: FLASH setup, tuning, and operation (Leaders: B. Faatz, J. Carwardine)

During the September 2009 studies, it took more than 10 shifts of expert tuning to achieve low-loss transmission of several hundred 3nC bunches. To make efficient use of future studies periods, it will be necessary to tune the machine reliably and consistently much more rapidly. This group will consider what is necessary to accomplish that, such as: identifying ‘golden’ working points using detailed information archived in the FLASH DAQ; tuning strategies; procedures and automation; parameter reproducibility and stability; diagnostics; accelerator modeling; extrapolation to XFEL. Differences between 1nC and 3nC bunch charges should be considered.

Working Group #2: FLASH feedback and control (Leaders: H. Schlarb, V. Ayvazyan)

Robust feedback systems are crucial achieving stable and repeatable performance. The LLRF systems regulate the cavity vector sums using feedback within the bunch train and by adjusting the RF drive waveforms pulse-to-pulse (‘adaptive feed forward’). Beam-based feedbacks are used to stabilize the bunch arrival times and compression factors at the end of the bunch compressor chicanes and the beam orbits from injector to beam dump. Topics for this group include: examining the performance and robustness of these feedback systems and considering possible improvements to algorithms and implementation; exception and error handling.

Working Group #3: ILC studies at FLASH (Leaders: N. Solyak, S. Michizono)

The FLASH 9mA study program was jointly initiated by DESY and the ILC Global Design Effort in order to demonstrate and study operation of the Tesla/ILC superconducting accelerating cavities with full beam loading and long bunch trains. The study program is focused on characterizing operations limitations to achieving ILC energy stability requirements for the main linac and bunch compressors: LLRF performance; accelerating cavity gradient operating margins; RF power operating margins. The group will evaluate data from the September studies and develop proposals for future future studies.

Working Group #4: DAQ and data analysis (Leaders: T. Wilksen, N. Arnold)

This working group will focus on tools and techniques for analyzing accelerator data from the FLASH DAQ. The emphasis will be on usage of the DAQ data rather than on detailed DAQ system implementation. Specific analysis use-cases will be developed ahead of time and then refined in collaboration with the other working groups. The group will explore implementation of these use-cases. Requirements for online and operations tools and offline analysis toolkits will be explored.
Working Group 2 Summary
Working Group 3 Summary
Working Group 4 Summary
Support
  • Monday 22 February
    • Plenary I: Welcome and FLASH status Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
      • 1
        Welcome remarks
        Speaker: Reinhard Brinkmann (DESY)
      • 2
        Status of long-bunch trains in FLASH
        Speaker: Dr Nicholas Walker (DESY)
        Slides
      • 3
        Outlook for FLASH and FLASH 2
        Speaker: Dr Siegfried Schreiber (DESY)
        Slides
    • 10:30
      Coffee Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
    • Plenary II: FLASH as a test facility Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
      • 4
        ILC goals for FLASH
        Speaker: Marc Ross (Fermilab)
        Slides
      • 5
        XFEL goals for FLASH
        Speaker: Dr Torsten Limberg (DESY)
        Slides
      • 6
        FLASH photon users opportunities for long bunch trains
        Speaker: Dr Josef Feldhaus (DESY)
        Slides
    • 12:00
      Lunch Canteen

      Canteen

      DESY

      Notkestr. 85 22607 Hamburg
    • Plenary III: September 9mA run Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
      • 7
        Data available from 9mA run (DAQ and analysis tools)
        Speaker: Tim Wilksen (DESY)
        Slides
      • 8
        Beam stability and beam loss issues
        Speaker: John Carwardine (Argonne)
        Slides
      • 9
        LLRF 9mA operations and data analysis - I
        Speaker: Dr Valeri Ayvazyan (DESY)
        Slides
      • 10
        LLRF 9mA operations and data analysis - II
        Speaker: Gustavo Cancelo (FNAL)
        Slides
      • 11
        Dumpline instrumentation
        Speaker: Dr Nicoleta Baboi (DESY)
        Slides
      • 12
        Discussion
    • 15:50
      Coffee Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
    • Plenary IV: Working Group introductions Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
      • 13
        WG 1: FLASH setup, tuning & operations
        Speakers: Dr Bart Faatz (HASYLAB), John Carwardine (Argonne)
      • 14
        WG 2: FLASH Feedback & Control
        Speakers: Dr Holger Schlarb (DESY), Dr Valeri Ayvazyan (DESY)
        Slides
      • 15
        WG 3: ILC (9mA) Studies at FLASH
        Speakers: Nikolay Solyak (Fermilab), Shinichiro Michizono (KEK)
        Slides
      • 16
        WG 4: DAQ & Controls
        Speakers: Ned Arnold (Argonne), Tim Wilksen (DESY)
        Slides
      • 17
        Discussion
  • Tuesday 23 February
    • Working Group 1: Low-loss tuning experiences Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
      slides
      • 18
        Session introduction, WG goals
        Speaker: Bart Faatz (DESY)
      • 19
        An operation model for rapid tuning and recovery
        Speaker: John Carwardine (Argonne)
      • 20
        Low-loss tuning issues from 9mA studies
        Speaker: Dr Nicholas Walker (DESY)
        Slides
      • 21
        Injector setup, tuning, matching experience with long bunch trains
        Speaker: Siegfried Schreiber (DESY)
        Slides
      • 22
        Discussion
    • Working Group 2: LLRF firmware/DOOCS servers Sem.R. 3, Bldg. 1b

      Sem.R. 3, Bldg. 1b

      DESY

      Notkestr. 85 22607 Hamburg
      • 23
        Summary of structure and functionality of SIMCON firmware and DOOCS
        Speaker: Wojciech Jalmuzna (DESY)
        Slides
      • 24
        LLRF firmware upgrade for FLASH
        Speaker: Waldemar Koprek (DESY)
        Slides
      • 25
        LLRF front-end server, FSM and beam pattern implementation
        Speaker: Olaf Hensler (DESY)
        Slides
      • 26
        Discussion
    • Working Group 3: HOM absorbers/rf input limitations Sem.R. 3a, Bldg. 1b

      Sem.R. 3a, Bldg. 1b

      DESY

      Notkestr. 85 22607 Hamburg
      • 27
        HOM absorber studies
        Speaker: Jacek Sekutowicz (DESY)
        Slides
      • 28
        Study of absorber effectiveness in ILC cavities
        Speakers: Dr Chris Adolphsen (SLAC), Karl Bane (SLAC)
        Slides
      • 29
        Discussion
    • Working Group 4 Room 362, Bldg. 30b

      Room 362, Bldg. 30b

      DESY

      Notkestr. 85 22607 Hamburg
      • 30
        Introduction to WG4 sessions: scope and goals
        Speaker: Ned Arnold (Argonne)
      • 31
        Review DAQ Survey results: Presentation of results and brief discussion
        Speakers: Ned Arnold (Argonne), Tim Wilksen (DESY)
        Slides
      • 32
        Experience with use cases using MATLAB
        Speaker: Ned Arnold (Argonne)
      • 33
        Experience with use cases using SDDS
        Speaker: Robert Soliday (ANL)
        Slides
      • 34
        Experience with use cases and FLASH DAQ tools
        Speaker: Vladimir Rybnikov (DESY)
        Slides
      • 35
        Discussion
    • 10:40
      Coffee Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
    • Working Group 1: Diagnostics, LLRF tuning Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
      • 36
        Session introduction
        Speaker: Bart Faatz (DESY)
      • 37
        Single bunch diagnostics
        Speaker: Christopher Gerth (DESY)
        Slides
      • 38
        Transverse diagnostics
        Speaker: Dr Nicoleta Baboi (DESY)
        Slides
      • 39
        Energy measurements in the bypass line
        Speaker: Raimund Kammering (DESY)
        Slides
      • 40
        LLRF setup and tuning for long bunch trains
        Speaker: Dr Valeri Ayvazyan (DESY)
        Slides
      • 41
        Discussion
    • Working Group 3 Sem.R. 3, Bldg. 1b

      Sem.R. 3, Bldg. 1b

      DESY

      Notkestr. 85 22607 Hamburg
      • 42
        Latest results on beam loaded experiments at FLASH
        Speakers: Chris Adolphsen (SLAC), Shilun Pei
        Slides
      • 43
        Results of high-gradient study
        Speaker: Shinichiro Michizono (KEK)
        Slides
      • 44
        High gradients with 9mA beam
        Speaker: Julien Branlard (FNAL)
        Slides
      • 45
        Discussion
    • Working Group 4 Sem.R. 3a, Bldg. 1b

      Sem.R. 3a, Bldg. 1b

      DESY

      Notkestr. 85 22607 Hamburg
      • 46
        Continue talks on use case experience (if necessary)
      • 47
        Discussion and brainstorming usign survey and use case experiences focusing on a) Acquisition of data, b) Auto- or preprocessing of data and c) Tools or accessing and analyzing data
      • 48
        Option: Join LLRF setup and tuning talk of WG1
        Speaker: Dr Valeri Ayvazyan (DESY)
        Slides
      • 49
        Discussion and brainstorming using survey and use case experiences focusing on a) Acquisition of Data, b) Auto- or preprocessing of data and c) Tools or accessing and analyzing data
    • Working group 2 Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
      • 50
        LLRF high-level applications
        Speaker: Zheqiao Geng (DESY)
        Slides
      • 51
        Stability of Master oscillator + frequency distribution systems
        Speaker: Henning-Christof Weddig (DESY)
      • 52
        Discussion
    • 12:40
      Lunch Canteen

      Canteen

      DESY

      Notkestr. 85 22607 Hamburg
    • Working Group 1: Rapid machine setup and recovery Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
      • 53
        Session introduction
        Speaker: John Carwardine (Argonne)
      • 54
        Optics, orbit, dispersion
        Speaker: Eduard Prat (DESY)
        Slides
      • 55
        FLASH Save/Restore
        Speaker: Pedro Castro (DESY)
        Slides
      • 56
        Role of beam-based feedback in machine setup and recovery, eg ACC1 phase/amplitude
        Speaker: Dr Christopher Gerth (DESY Hamburg, MPY)
        Slides
      • 57
        Discussion
    • Working Group 2+3: LLRF experience from 9mA studies Sem.R. 3, Bldg. 1b

      Sem.R. 3, Bldg. 1b

      DESY

      Notkestr. 85 22607 Hamburg
      • 58
        Piezo tuner experiences from the 9mA studies
        Speaker: Mariusz Grecki (DESY)
        Slides
      • 59
        Cavity resonance frequency measurement
        Speaker: Waldemar Koprek (DESY)
        Slides
      • 60
        High beam loading operation of 3rd harmonic module
        Speaker: Dr Elmar Vogel (DESY)
        Slides
      • 61
        Consideration on ILC cavity field gradient and the operational margin
        Speaker: Akira Yamamoto (KEK)
        Slides
      • 62
        Discussion
    • Working Group 4 Sem.R. 3a, Bldg. 1b

      Sem.R. 3a, Bldg. 1b

      DESY

      Notkestr. 85 22607 Hamburg
      • 63
        Join WG1 (Save/Restore talk and Behrens talk)
      • 64
        Brainstorming on online DAQ/data use cases - prepare joint WG1 + WG4 session
    • 15:40
      Coffee Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
    • Working Group 1+4: Rapid setup, online/offline data analysis Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
      • 65
        Session introduction
        Speaker: Tim Wilksen (DESY)
        Slides
      • 66
        TINE archiver tool for online operations
        Speaker: Mark Lomperski (DESY)
      • 67
        Online operations use-cases of DAQ
        Speakers: Ned Arnold (Argonne), Tim Wilksen (DESY)
      • 68
        Offline data analysis use-cases of DAQ
        Speakers: Ned Arnold (Argonnne National Laboratory), Tim Wilksen (DESY)
        Paper
      • 69
        Discussion
    • Working Group 2+3 (WG3 agenda) Sem.R. 3, Bldg. 1b

      Sem.R. 3, Bldg. 1b

      DESY

      Notkestr. 85 22607 Hamburg
      • 70
        Study of stability requirements for ILC bunch compressor (best off-crest)
        Speaker: Nikolay Solyak (Fermilab)
        Slides
      • 71
        Comparison between ILC spec. and FLASH 9mA study
        Speaker: Brian Chase (FNAL)
        Slides
      • 72
        Future works for long-pulse high beam loading demonstration
        Speaker: Gustavo Cancelo (FNAL)
        Slides
      • 73
        Discussion
    • 19:00
      Dinner in the DESY Bistro Bistro, Bldg. 9

      Bistro, Bldg. 9

      DESY

      Notkestr. 85 22607 Hamburg
  • Wednesday 24 February
    • WG 1: summary preparation Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
    • WG 2: summary preparation Sem.R. 3, Bldg. 1b

      Sem.R. 3, Bldg. 1b

      DESY

      Notkestr. 85 22607 Hamburg
    • WG 3: summary preparation Sem.R. 3a, Bldg. 1b

      Sem.R. 3a, Bldg. 1b

      DESY

      Notkestr. 85 22607 Hamburg
    • WG 4: summary preparation Room 362, Bldg. 30b

      Room 362, Bldg. 30b

      DESY

      Notkestr. 85 22607 Hamburg
    • 10:30
      Coffee Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
    • WG summaries Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
      • 74
        WG-1 summary
        Speakers: Bart Faatz (DESY), John Carwardine (Argonne)
        Slides
      • 75
        WG-2 summary
        Speakers: Dr Holger Schlarb (DESY), Dr Valeri Ayvazyan (DESY)
        Slides
      • 76
        WG-3 summary
        Speakers: Nikolay Solyak (Fermilab), Shinichiro Michizono (KEK)
        Slides
      • 77
        WG-4 summary
        Speakers: Ned Arnold (Argonne), Tim Wilksen (DESY)
        Slides
      • 78
        Wrap-up (future plans)
        Speaker: Dr Siegfried Schreiber (DESY)
        Slides
      • 79
        Closing remarks
    • End of Workshop Sem. R. 1, Bldg. 1

      Sem. R. 1, Bldg. 1

      DESY

      Notkestr. 85 22607 Hamburg
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