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Mini-workshop on beam-line field-emitter particulates in CEBAF SRF linacs

US/Eastern
TL1227 (Test Lab)

TL1227

Test Lab

Rong-Li Geng (Thomas Jefferson National Accelerator Facility)
Description
Goal: Evaluate field-emission impact to operation of CEBAF SRF linacs. Identify the root cause(s) of particulate field-emitters in operational SRF cavities, with a focus on the particulates originating from the UHV beam-line components. Develop solutions for “particulate-free” beam-line components for future SRF linacs as well as mitigations against accumulated field emitter particulates for operational SRF linacs. Topics: • Observations and experiences with beam-line particulates and correlation with field-emission. • Sources of particulates in UHV beam-line components. • Roles of condensed residual gases. • Mechanisms of particulate transportation in UHV beam-lines. • UHV beam-line component design for lowest particulate generation. • UHV beam-line component cleaning, handling, assembly and operation procedure for lowest particulate generation. • Mitigation against field-emitter particulate in operational SRF linacs. • Techniques for removal of accumulated field emission particulates. • UHV beam line-particulate detection technique. • Fast detectors for in operando monitoring of field-emission turn on. Program committee: Rongli Geng (Chair), SRF R&D, AD Arne Freyberger, CEBAF Operation, AD Geoff Krafft, CASA/AD office, AD Tim Michalski, Mechanical Engineering, ED Tony Reilly, SRF Operation, AD
    • 09:00 09:15
      Aim of the workshop 15m TL1227

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      Speaker: Dr Rong-Li Geng (Thomas Jefferson National Accelerator Facility)
      Slides
    • 09:15 09:30
      Technical and economical motivation 15m TL1227

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      Speaker: Arne Freyberger (JLAB-Accelerator Division-Operations Department)
      Slides
    • 09:30 10:00
      FE experiences with C100 module operation 30m TL1227

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      Speakers: Clyde Mounts (EESRFS), Mr Rama Bachimanchi (Jefferson Lab)
      Slides
    • 10:00 10:30
      Evolution of FE characteristics of selected modules 30m TL1227

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      Speaker: Mr Michael Drury (Jefferson :Lab)
      Slides
    • 10:30 12:00
      Review of current practices TL1227

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      Review of current practices in cavity string assembly, cryomodule installation, warm girder UHV components installation/maitenance. Give special attention to designs/procedures aimed for minimizing particulate generation/transportation.

      • 10:30
        C100 cavity string assembly 15m
        Speaker: Kurt Macha (Jefferson Lab)
        Slides
      • 10:45
        Cryomodule installation in CEBAF tunnel 15m
        Speaker: John Fischer (Jefferson Lab)
        Slides
      • 11:00
        Warm girder UHV components 1h
        Speakers: Anthony DiPette (Jefferson Lab), John Hechman (Jefferson Lab)
        Slides
    • 12:00 13:00
      Lunch (on your own) 1h
    • 13:00 14:45
      Panel discussion TL1227

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      Panelist: Anthony Dipette, John Fischer, John Heckman, Kurt Macha

      Convener: Dr Rong-Li Geng (Thomas Jefferson National Accelerator Facility)
    • 14:45 15:00
      LCLS-II cryomodule installation planning 15m TL1227

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      Speaker: Dr Chris Adolphsen (SLAC)
      Slides
    • 15:00 15:30
      Brainstorm action list TL1227

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      • Near term actionable items to slow down FE particulate generation
      • Particulate-free UHV component design for SRF linacs

      Conveners: Anthony Reilly (JLAB), Tim Michalski (Jefferson Lab)
      • 15:00
        NEG pumps 5m
        Speaker: Marcy Stutzman (Jefferson Lab)
        Slides
    • 15:30 15:55
      Brainstorm action list TL1227

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      • Future on-line and off-line testing
      • Future studies on particulate transportation e-beams
      • Long term implementable mitigations

      Convener: Geoff Krafft (JLab)
      slides
    • 15:55 16:00
      Closeout 5m TL1227

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      Speaker: Dr Rong-Li Geng (Thomas Jefferson National Accelerator Facility)
    • 16:00 16:01
      Adjourn TL1227

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