Six-Month Follow-Up on Action Items of Feb 2016 CEBAF Field Emitter Workshop

TL1227 (Test Lab)


Test Lab

Arne Freyberger (JLAB-Accelerator Division-Operations Department), Geoff Krafft (JLab), Rong-Li Geng (Thomas Jefferson National Accelerator Facility)
It has been about six months since the February 29 mini-workshop on field emitter particulates in CEBAF beamlines. Progresses have been made or are being made in several fronts related to the action items, all aligned with the goal of understanding and reduce field emission in CEBAF. A six-month follow-up is deemed conducive to the final goal of reversing the "lost gradient" in CEBAF. Toward that end, a special PIT meting is to be conducted on September 12, 2016 to allow capturing and measuring the initial results of all efforts related to the action items. Please keep your presentation succinct. If you have any questions regarding your presentation, please ask Rongli. You can find references to the February 29, 2016 Mini-Workshop on Beam Line Field Emitter Particulate in CEBAF SRF Linacs at this web link:
    • 13:25 13:30
      Introduction 5m
      Speaker: Dr Rong-Li Geng (Thomas Jefferson National Accelerator Facility)
    • 13:30 13:35
      Field emission onset data from present C50 module C50-12 CMTF testing and comparison against prior C50 modules (1-11) 5m
      Speaker: Mr Michael Drury (Jefferson :Lab)
    • 13:35 13:40
      Field Emission onset data from VTA testing of C50-12 cavity pairs as compared to prior C50 cavities pairs 5m
      Speaker: Liang Zhao (JLab/W&M)
    • 13:40 13:50
      Improved procedure and practice in C50-12 cavity string assembly as compared to prior C50 strings 10m
      Speaker: Danny Forehand (JLAB)
    • 13:50 14:00
      Improved procedure and practice in C50-12 cryomodule assembly as compared to prior C50 cryomodules with a special attention to the step of supply-end-can side UHV manifold attachment 10m
      Speakers: Frank Humphries (JLAB), Gianluigi Ciovati (JLab), John Fischer (JLAB)
    • 14:00 14:05
      Gas load desorbed from room temperature warming up of cryomodules and rationale for next generation beamline vacuum system 5m
      Speaker: Dr Rong-Li Geng (Thomas Jefferson National Accelerator Facility)
    • 14:05 14:15
      NEG pump for C50-12 and initial experience 10m
      Speakers: Kurt Macha (JLAB), Dr Marcy Stutzman (Jefferson Lab)
    • 14:15 14:25
      Off-line evaluation of NEG pump by integrated vertical testing a single-cell cavity 10m
      Speaker: Gianluigi Ciovati (JLab)
    • 14:25 14:30
      Hi-potting halted or not? Evidence of benefit? 5m
      Speaker: Arne Freyberger (JLAB-Accelerator Division-Operations Department)
    • 14:30 14:50
      Design and implementation of a new clean room environment for tunnel work and first use for NL12 warm girders and next steps for improvements 20m
      Speaker: Mr John Heckman (JSA)
    • 14:50 15:00
      First experience of “particulate free” warm girder NL12 & NL13 assembly with real-time particulate monitoring and identified improvements for next round of practice 10m
      Speakers: Chris Dreyfuss (JLAB), Danny Forehand (JLAB), Greg Marble (JLAB)
    • 15:00 15:05
      Design and first use of the slow venting apparatus for NL12 warm girders and future improvements 5m
      Speakers: Dr Ari Palczewski (Jefferson Lab), Danny Forehand (JLAB)
    • 15:05 15:25
      Particulates collected and analyzed from UHV surfaces of NL12 and NL13 warm girder components 20m
      Speakers: Dr Anne-Marie Valente-Feliciano (Jefferson Lab), Charles Reece (JLab), Mr Joshua Spradlin (Jefferson Lab)
    • 15:25 15:30
      Post-mortem investigation of leaky gate valves (warm gate valves and cold valves): condition of Viton O-ring in terms of particulate shedding and nature of failure 5m
      Speakers: Greg Marble (JLAB), Dr Rong-Li Geng (Thomas Jefferson National Accelerator Facility)