bmad_4260_092605_v1.lat

September 26, 2005 Lattice: /nfs/cesr/user/dlr/lat/bmad_4260_092605_v1.lat

Design plan

• Turn off all sextupoles
• set pretzel to ~10% nominal so no significant electron positron difference
• SCIR quads, and arc quads north of 13 are overlayed (east west symmetric)
• Noteworthy linear optics constraints
  • alpha=0 at L0 and L3.
  • beta_v*=12mm
  • eta*=0. Note that etap* is NOT constrained. This is important because the pretzel introduces nonzero etap* even with no sextupoles. It will be taken out later when sextupoles are turned back on. We cannot zero it for both beams with quadrupoles.
  • emittance < 130nm
  • Pretzel efficiency
  • Arc eta < 3.5m. This seems to simplify design of sextupole distribution
• Restore pretzel to nominal value.
• Add B_param to constraint list
• H_sep 45E/W are overlayed. Vary only one of seps 8E or 8W. Then scale entire pretzel to 18.5mm displacement
• Restore sextupoles in 2 family distribution
• Sextupoles are overlayed E/W
• Noteworthy nonlinear optics constraints
  • etap*=0 both beams (Minimize difference of electron and positron dispersion in Q2 east and west)
  • Constrain electron positron dispersion difference at arc peak (Q24)
  • 2Qx-Qs driving term
  • det_4by4

• linear lattice constraints
• non linear lattice constraints

• lattice file
• Optical parameters and orbits
  • table
  • Lattice gif

  • Parasitic crossing parameters
    • Luminosity pretzel - pc parameters , b_param

  • Dynamic aperture
    092805 and initialization energies 0.0 0.003 0.006, Qx=0.518,Qy=0.584, Qz=-0.089

  • Parameters for beam-beam simulation including radiation integrals, damping decrement, etc.
  • Closed orbit output
  • c12_c22 in IR
  • Single beam size (tracking 500k Turns last 50k turns)

  Single particle scans

  • 092805 and initialization , fs=-0.089, positrons, nolrbbi, no beambeam_ip, lat_and_layout (including apertures)

  Luminosity vs current

  • 092805 and initialization qz=-0.089 and compared to 1.885 GeV optics, hibetainj_20040628_v01 gif
  • 100605-1 and initialization qx=0.519, Qy=0.588, qz=-0.089. These tunes gave best performance in 093005 scan. and compared to 1.885 GeV optics, hibetainj_20040628_v01 and bb_092805 gif

  Beambeam scan

  • lumscan_093005 and initialization 2mA, qz=-0.089, sizescan_093005 , lossscan_093005

  Energy dependence of beta

  • dbeta/d delta E positrons , electrons

  Energy dependence of coupling