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Electron Cloud Issues

Electron Cloud Issues. A.Kulikov SLAC MAC review October 2003. Electron multipacting in the LER straight sections. Feb. 2000 50 nTorr @ 1 A. Feb. 2000 25 nTorr @ 1.1A. Current, mA. Current, mA. Oct. 2003 5.5 nTorr @ 1.5 A. Oct. 2003 1.2nTorr @ 1.5 A. Current, mA.

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Electron Cloud Issues

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  1. Electron Cloud Issues A.Kulikov SLAC MAC review October 2003

  2. Electron multipacting in the LER straight sections. Feb. 2000 50 nTorr @ 1 A Feb. 2000 25 nTorr @ 1.1A Current, mA Current, mA Oct. 2003 5.5 nTorr @ 1.5 A Oct. 2003 1.2nTorr @ 1.5 A Current, mA Current, mA

  3. Electrons in the HER. All HER holding vac. pumps HER distributed ion pumps

  4. Electrons in the LER arcs 3.1E12 VP4031 09_29_03 Elec4031 09-29-03 VP4031 (6-8)-Jul-01 Solenoid OFF VP4031 15-Aug-01 Solenoid ON 14-Aug-01

  5. Electron multipacting and luminosity July 2000 29 sections ON 2-May-2000 Before 17:00: 10 sections of solenoids ON (Str. 12) After 18:15: 23 sections ON (Str. 12, Str. 4, Str. 8) 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

  6. Positron beam sizes driven by the electron cloud effect 31-Jul-2000

  7. Str.12 solenoids effect on the beam sizes.All other solenoids in the ring are ON, single ring. Lifetime Horizontal beam size Vertical beam size ON OFF 1.46 A 450 mA 28-Aug-01

  8. Solenoids Arc-3 effect on the beam sizes.All other solenoids are ON, single beam. Lifetime Horizontal beam size Vertical beam size 1.5 A ON OFF 0.5 A 28-Aug-01

  9. 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

  10. 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.

  11. 50 Gauss solenoid section

  12. Pumping T

  13. Double the field at the pumping T-s

  14. “No sextupole” chamber

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