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Working group: Collective effects

Working group: Collective effects. Manuela Boscolo Theo Demma INFN Sasha Novokhatski SLAC. 01/29/2009 discussion. Touschek background and lifetime e-cloud Impedance budget ions. M.Boscolo. SuperB Parameters (June 2008). nominal CDR lattice:.

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Working group: Collective effects

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  1. Working group:Collective effects Manuela Boscolo Theo Demma INFN Sasha Novokhatski SLAC

  2. 01/29/2009 discussion • Touschek background and lifetime • e-cloud • Impedance budget • ions

  3. M.Boscolo

  4. SuperBParameters (June 2008) nominal CDR lattice: now Nb slightly lower (LER/HER 6.16/3.52) now higher LER horiz. emitt. (LER/ HER 1.6/1.6) now higher Tou. lifetime (LER/ HER 3.6/5.1)

  5. generated Touschek particles per second all over the ring Dp/p Ploss 1 turn trackedparticles with Dp/p= 0.6%-0.8% are lost, with some efficiency. These have very large weight, this induces difference in lifetime estimation (Touschek function very non linear) SuperB: Comparison between lifetime estimate from formula and calculation from tracking (CDR lattice) Reference: t(CDR)=330 s (Wienands) assuming that particles with |Dp/p|>1% are lost (like CDR): t = 308 s good agreement with CDR efficiency calculated from tracking t = 200 s

  6. M.Boscolo

  7. MAD STAR MAD STAR Optical functions Jan09 lattice dx Jan09 linear lattice ready for the Touschek and beam-gas simulations

  8. New IR from Mike implemented in bkg codehorizontal physical aperture zoomed view x(m) x(m) beam beam QF QD0 PM PM QD0 QF s(m) s(m)

  9. M.Boscolo

  10. Beam-gas M. Boscolo Simulation studies on DAFNE to compare experimental data (but here Touschek is dominant) a simulation tool to handle this effect has been developed in progress for SuperB: in Orsay some simulation studies with Jan09 lattice and maybe first collimators set

  11. T.Demma

  12. T.Demma

  13. T.Demma

  14. T.Demma

  15. T.Demma

  16. Simulate PEP-II electron cloud in straights

  17. Bunch lengthening. S.Novokhatski 18 01/26/09

  18. Impedance budget S.Novokhatski In progress

  19. Ions S.Novokhatski • There will be a gap – Studies are planned to decide how large it should be at PEP-II gap was about 1% At the very end of PEP-II running (April 2008) number of bunches was 1726 (bunch pattern by 2), ion gap was 20 bunches that equals to 40 RF buckets or 84 nsec. HER beam current was close to 2 A equivalent bunch charge was 2A*7.336E-06sec/1726=8.5 nC.

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