Electron Cloud Issues
-
Upload
reed-zamora -
Category
Documents
-
view
30 -
download
2
description
Transcript of Electron Cloud Issues
![Page 1: Electron Cloud Issues](https://reader036.fdocuments.us/reader036/viewer/2022062407/56812cdc550346895d919fcd/html5/thumbnails/1.jpg)
Electron Cloud Issues
A.Kulikov
SLAC
MAC review October 2003
![Page 2: Electron Cloud Issues](https://reader036.fdocuments.us/reader036/viewer/2022062407/56812cdc550346895d919fcd/html5/thumbnails/2.jpg)
Electron multipacting in the LER straight sections.
Current, mA Current, mA
Current, mA Current, mA
Feb. 2000 25 nTorr @ 1.1AFeb. 2000 50 nTorr @ 1 A
Oct. 2003 5.5 nTorr @ 1.5 A Oct. 2003 1.2nTorr @ 1.5 A
![Page 3: Electron Cloud Issues](https://reader036.fdocuments.us/reader036/viewer/2022062407/56812cdc550346895d919fcd/html5/thumbnails/3.jpg)
Electrons in the HER.
All HER holding vac. pumps HER distributed ion pumps
![Page 4: Electron Cloud Issues](https://reader036.fdocuments.us/reader036/viewer/2022062407/56812cdc550346895d919fcd/html5/thumbnails/4.jpg)
Electrons in the LER arcs
VP4031 09_29_03
VP4031 (6-8)-Jul-01Solenoid OFF
VP4031 15-Aug-01Solenoid ON 14-Aug-01
Elec4031 09-29-03
3.1E12
![Page 5: Electron Cloud Issues](https://reader036.fdocuments.us/reader036/viewer/2022062407/56812cdc550346895d919fcd/html5/thumbnails/5.jpg)
![Page 6: Electron Cloud Issues](https://reader036.fdocuments.us/reader036/viewer/2022062407/56812cdc550346895d919fcd/html5/thumbnails/6.jpg)
Electron multipacting and luminosity
2-May-2000Before 17:00: 10 sections of solenoids ON (Str. 12)After 18:15: 23 sections ON (Str. 12, Str. 4, Str. 8)
July 200029 sections ON
The last section in the straights was energized 16-Mar-01 (54 total)
Solenoids in the LER arcs: the first - 23-Apr-01, the last - 9-Feb-02
![Page 7: Electron Cloud Issues](https://reader036.fdocuments.us/reader036/viewer/2022062407/56812cdc550346895d919fcd/html5/thumbnails/7.jpg)
Positron beam sizes driven by the electron cloud effect
31-Jul-2000
![Page 8: Electron Cloud Issues](https://reader036.fdocuments.us/reader036/viewer/2022062407/56812cdc550346895d919fcd/html5/thumbnails/8.jpg)
Str.12 solenoids effect on the beam sizes.All other solenoids in the ring are ON, single ring.
28-Aug-01
Lifetime Horizontal beam size Vertical beam size
1.46 A
450 mA
ON
OFF
![Page 9: Electron Cloud Issues](https://reader036.fdocuments.us/reader036/viewer/2022062407/56812cdc550346895d919fcd/html5/thumbnails/9.jpg)
Solenoids Arc-3 effect on the beam sizes.All other solenoids are ON, single beam.
Lifetime Horizontal beam size Vertical beam size
ON
OFF
1.5 A
0.5 A
28-Aug-01
![Page 10: Electron Cloud Issues](https://reader036.fdocuments.us/reader036/viewer/2022062407/56812cdc550346895d919fcd/html5/thumbnails/10.jpg)
Solenoid field scan (Bmax = 30Gauss)4” round SS chamber, colliding beams
Bunch pattern - by 3 LER current - (1.45 - 1.25) A Number of bunches - 1078
![Page 11: Electron Cloud Issues](https://reader036.fdocuments.us/reader036/viewer/2022062407/56812cdc550346895d919fcd/html5/thumbnails/11.jpg)
Summer 2003 improvements:
Additional 50 Gauss solenoids for all straight sections drift chambers.
Double the field at pumping T-s, transitions and small drift chambers for all LER straight sections.
Additional solenoids for “no sexstupole” girders in all LER arcs.
![Page 12: Electron Cloud Issues](https://reader036.fdocuments.us/reader036/viewer/2022062407/56812cdc550346895d919fcd/html5/thumbnails/12.jpg)
50 Gauss solenoid section
![Page 13: Electron Cloud Issues](https://reader036.fdocuments.us/reader036/viewer/2022062407/56812cdc550346895d919fcd/html5/thumbnails/13.jpg)
Pumping T
![Page 14: Electron Cloud Issues](https://reader036.fdocuments.us/reader036/viewer/2022062407/56812cdc550346895d919fcd/html5/thumbnails/14.jpg)
Double the field at the pumping T-s
![Page 15: Electron Cloud Issues](https://reader036.fdocuments.us/reader036/viewer/2022062407/56812cdc550346895d919fcd/html5/thumbnails/15.jpg)
“No sextupole” chamber