new results on field emission suppression in ep multi-cell cavities at jlab rong-li geng jefferson...
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![Page 1: New Results on Field Emission Suppression in EP Multi-Cell Cavities at JLab Rong-Li Geng Jefferson Lab ILC10, March 26-30, 2010, Beijing, China](https://reader036.vdocuments.net/reader036/viewer/2022062423/56649e1f5503460f94b0ac77/html5/thumbnails/1.jpg)
New Results on Field Emission Suppression
in EP Multi-Cell Cavities at JLab
Rong-Li GengJefferson Lab
ILC10, March 26-30, 2010, Beijing, China
![Page 2: New Results on Field Emission Suppression in EP Multi-Cell Cavities at JLab Rong-Li Geng Jefferson Lab ILC10, March 26-30, 2010, Beijing, China](https://reader036.vdocuments.net/reader036/viewer/2022062423/56649e1f5503460f94b0ac77/html5/thumbnails/2.jpg)
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Field Emission On-set Analysis of EP Multi-Cell Cavities at JLab
Rongli Geng ILC10, 3/26-30, 2010, Beijing, Chnia
Gradient at which first X-ray detected above background
![Page 3: New Results on Field Emission Suppression in EP Multi-Cell Cavities at JLab Rong-Li Geng Jefferson Lab ILC10, March 26-30, 2010, Beijing, China](https://reader036.vdocuments.net/reader036/viewer/2022062423/56649e1f5503460f94b0ac77/html5/thumbnails/3.jpg)
ILC10, 3/26-30, 2010, Beijing, Chnia 3
First EP 7-Cell Cavity w/o FE at 35 MV/mthis results directed us to EP 9-cell at lower temperature
Rongli Geng
R.L. Geng et al., LINAC08
![Page 4: New Results on Field Emission Suppression in EP Multi-Cell Cavities at JLab Rong-Li Geng Jefferson Lab ILC10, March 26-30, 2010, Beijing, China](https://reader036.vdocuments.net/reader036/viewer/2022062423/56649e1f5503460f94b0ac77/html5/thumbnails/4.jpg)
ILC10, 3/26-30, 2010, Beijing, Chnia 4
Maximum Gradient in EP Multi-Cell Cavities
Rongli Geng
![Page 5: New Results on Field Emission Suppression in EP Multi-Cell Cavities at JLab Rong-Li Geng Jefferson Lab ILC10, March 26-30, 2010, Beijing, China](https://reader036.vdocuments.net/reader036/viewer/2022062423/56649e1f5503460f94b0ac77/html5/thumbnails/5.jpg)
ILC10, 3/26-30, 2010, Beijing, Chnia 5
Example of EP 9-Cell Cavity w/o FE
Rongli Geng
![Page 6: New Results on Field Emission Suppression in EP Multi-Cell Cavities at JLab Rong-Li Geng Jefferson Lab ILC10, March 26-30, 2010, Beijing, China](https://reader036.vdocuments.net/reader036/viewer/2022062423/56649e1f5503460f94b0ac77/html5/thumbnails/6.jpg)
ILC10, 3/26-30, 2010, Beijing, Chnia 6
Latest EP 9-Cell Result w/o FE at 40 MV/m
Rongli Geng
41 MV/m reached during initial power rise, at which gradient precursor FE startedLater power rise limited to 40 MV/m to prevent explosive emitter activation
![Page 7: New Results on Field Emission Suppression in EP Multi-Cell Cavities at JLab Rong-Li Geng Jefferson Lab ILC10, March 26-30, 2010, Beijing, China](https://reader036.vdocuments.net/reader036/viewer/2022062423/56649e1f5503460f94b0ac77/html5/thumbnails/7.jpg)
ILC10, 3/26-30, 2010, Beijing, Chnia 7
Summary
Rongli Geng
• In more than a dozen of 35-40 MV/m EP multi-cell cavity tests, more than 80% demonstrated FE-free performance.
• Improvements in several aspects of cavity processing, handling and assembly are found beneficial.
• Gradient push beyond 40 MV/m are sometimes stopped in view of pre-cursor FE turn on.
• Further studies needed to fully understand the phenomenon.