Mini-workshop on beam-line field-emitter particulates in CEBAF SRF linacs
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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
9:00 AM
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9:15 AM
Aim of the workshop15mTL1227
TL1227
Test Lab
Speaker:
DrRong-Li Geng(Thomas Jefferson National Accelerator Facility)
Slides
9:15 AM
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9:30 AM
Technical and economical motivation15mTL1227
TL1227
Test Lab
Speaker:
Arne Freyberger(JLAB-Accelerator Division-Operations Department)
Slides
9:30 AM
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10:00 AM
FE experiences with C100 module operation30mTL1227
Evolution of FE characteristics of selected modules30mTL1227
TL1227
Test Lab
Speaker:
MrMichael Drury(Jefferson :Lab)
Slides
10:30 AM
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12:00 PM
Review of current practicesTL1227
TL1227
Test Lab
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 AM
C100 cavity string assembly15m
Speaker:
Kurt Macha(Jefferson Lab)
Slides
10:45 AM
Cryomodule installation in CEBAF tunnel15m
Speaker:
John Fischer(Jefferson Lab)
Slides
11:00 AM
Warm girder UHV components1h
Speakers:
Anthony DiPette(Jefferson Lab), John Hechman(Jefferson Lab)
Slides
12:00 PM
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1:00 PM
Lunch (on your own)
1h
1:00 PM
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2:45 PM
Panel discussionTL1227
TL1227
Test Lab
Panelist: Anthony Dipette, John Fischer, John Heckman, Kurt Macha
Convener:
DrRong-Li Geng(Thomas Jefferson National Accelerator Facility)
2:45 PM
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3:00 PM
LCLS-II cryomodule installation planning15mTL1227
TL1227
Test Lab
Speaker:
DrChris Adolphsen(SLAC)
Slides
3:00 PM
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3:30 PM
Brainstorm action listTL1227
TL1227
Test Lab
• 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)
3:00 PM
NEG pumps5m
Speaker:
Marcy Stutzman(Jefferson Lab)
Slides
3:30 PM
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3:55 PM
Brainstorm action listTL1227
TL1227
Test Lab
• Future on-line and off-line testing
• Future studies on particulate transportation e-beams
• Long term implementable mitigations
Convener:
Geoff Krafft(JLab)
slides
3:55 PM
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4:00 PM
Closeout5mTL1227
TL1227
Test Lab
Speaker:
DrRong-Li Geng(Thomas Jefferson National Accelerator Facility)