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

chaired by Rong-Li Geng (Thomas Jefferson National Accelerator Facility)
Monday, 29 February 2016 from to (US/Eastern)
at Test Lab ( TL1227 )
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.   

•	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
Go to day
  • Monday, 29 February 2016
    • 09:00 - 09:15 Aim of the workshop 15'
      Speaker: Dr. Rong-Li Geng (Thomas Jefferson National Accelerator Facility)
      Material: Slides powerpoint file
    • 09:15 - 09:30 Technical and economical motivation 15'
      Speaker: Arne Freyberger (JLAB-Accelerator Division-Operations Department)
      Material: Slides pdf file
    • 09:30 - 10:00 FE experiences with C100 module operation 30'
      Speakers: Mr. Rama Bachimanchi (Jefferson Lab), Clyde Mounts (EESRFS)
      Material: Slides powerpoint file
    • 10:00 - 10:30 Evolution of FE characteristics of selected modules 30'
      Speaker: Mr. Michael Drury (Jefferson :Lab)
      Material: Slides powerpoint file
    • 10:30 - 12:00 Review of current practices
      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 15'
        Speaker: Kurt Macha (Jefferson Lab)
        Material: Slides powerpoint file
      • 10:45 Cryomodule installation in CEBAF tunnel 15'
        Speaker: John Fischer (Jefferson Lab)
        Material: Slides powerpoint file
      • 11:00 Warm girder UHV components 1h0'
        Speakers: Anthony DiPette (Jefferson Lab), John Hechman (Jefferson Lab)
        Material: Slides powerpoint file
    • 12:00 - 13:00 Lunch (on your own) ( )
    • 13:00 - 14:45 Panel discussion
      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 15'
      Speaker: Dr. Chris Adolphsen (SLAC)
      Material: Slides powerpoint file pdf file
    • 15:00 - 15:30 Brainstorm action list
      •	Near term actionable items to slow down FE particulate generation
      •	Particulate-free UHV component design for SRF linacs 
      Conveners: Tim Michalski (Jefferson Lab), Anthony Reilly (JLAB)
      • 15:00 NEG pumps 5'
        Speaker: Marcy Stutzman (Jefferson Lab)
        Material: Slides powerpoint file
    • 15:30 - 15:55 Brainstorm action list
      •	Future on-line and off-line testing
      •	Future studies on particulate transportation e-beams
      •	Long term implementable mitigations
      Convener: Geoff Krafft (JLab)
      Material: slides powerpoint file
    • 15:55 - 16:00 Closeout 5'
      Speaker: Dr. Rong-Li Geng (Thomas Jefferson National Accelerator Facility)
    • 16:00 - 16:01 Adjourn