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Plan for L/I Improvement

Plan for L/I Improvement. D. Rubin. Energy dependence of solenoid compensation. Solenoid on equilibrium beam size is ~ twice solenoid off size. Compensation scheme . PM, Q1, Q2 are rotated 4.5 degrees about axis, designed to compensate 1.5T solenoid at 5.3 GeV

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Plan for L/I Improvement

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  1. Plan for L/I Improvement D. Rubin Luminosity improvement plan

  2. Energy dependence of solenoid compensation Solenoid on equilibrium beam size is ~ twice solenoid off size Luminosity improvement plan

  3. Compensation scheme • PM, Q1, Q2 are rotated 4.5 degrees about axis, designed to compensate 1.5T solenoid at 5.3 GeV • Skew quad coils are superimposed on Q1 and Q2 for fine tuneing and energy reach • Skew quad 3, is third component in “3-pair” compensation scheme • The first bending magnet is immediately beyond skew quad 3 PM Q2 Q1 sk_q03e Skew quad 3 sk_q03w CLEO solenoid Luminosity improvement plan

  4. Compensation scheme Constraints: • 4X4 matrix from sk_q03w through sk_q03e (T3-3) is block diagonal • Matrix from sk_q03w to IP has the form and • Requires 3 antisymmetrically placed pairs of skew elements • namely sk_q03, q1, and q2 • Equivalently T3-3 is block diagonal and • c11=c12=c22= 0 at the IP for the full turn matrix • 3-pair compensation scheme There are no bending magnets within the compensation region Luminosity improvement plan

  5. =0.0 =0.00084 CESR-c 3 pair compensaton Qx=0.52 Qy=0.58 Qz=0.089 Separators off Begin tracking outside Of compensation region Xinit =2mm Luminosity improvement plan

  6. =0.0 =0.00084 No solenoid Qx=0.52 Qy=0.58 Qz=0.089 Separators off Begin tracking outside Of compensation region Xinit =2mm Luminosity improvement plan

  7. Solenoid Compensation • 3-pair compensation • Energy dependence of coupling parameters Luminosity improvement plan

  8. Compensating solenoid PM Q2 Q1 Skew quad CLEO solenoid Luminosity improvement plan

  9. Compensation with anti-solenoid Strategies • Set ∫Bantidl= -∫Bcleodl ~ 2(1.85T)(0.95m) = 2(1.76T-m) • Use 3-pair constraints (PM angle fixed at 4.5 degrees) • 4-pair constraints where PM angle is fourth degree of freedom [4-pair => transport to IP is block diagonal] • Minimize energy dependence of C3-3 and impose • 3 pair constraints T3-3 maps through insert from 3w to 3E and • What is the global coupling, insertion coupling, • and luminosity for each configuration Luminosity improvement plan

  10. Compensation with anti-solenoid 3 pair, no antisol 4 pair, antisol and pm tilt 3 pair, antisol 3 pair, antisol. Minimize dC/dE with antisol and PM tilt Luminosity improvement plan

  11. Luminosity improvement plan

  12. Luminosity vs energy derivatives of C3-3 for different compensation configurations Luminosity improvement plan

  13. Compensation with anti-solenoid 1.No solenoid 2.Minimize dC3-3 & anti-sol 3.4-pair & anti-sol 4. 3-pair & anti-sol 5. CESR-c, 3-pair & no anti-sol Luminosity improvement plan

  14. Compensation with anti-solenoid • Effectiveness of anti-solenoid depends on • details of compensation scheme • Consider • Energy dependence of full turn coupling parameters at IP • Energy dependence of insertion coupling parameters • Have yet to define configuration that reproduces • solenoid off performance Luminosity improvement plan

  15. Compensation with anti-solenoid Simulation indicates ~50% increase in specific luminosity with anti-solenoid To achieve that gain implies  0.2% coupling (sigma_y = 1 micron) What are the appropriate design criteria? Optics with minimum dC3-3/dE is no different from 4-pair compensation with 1.9deg PM tilt Optics with minimum dC3-3/dE => field of anti-solenoid X ~ 2 Is it possible to achieve equivalent of no solenoid? Installation January 2006 Luminosity improvement plan

  16. Luminosity improvement plan

  17. Anti-solenoid in IR Luminosity improvement plan

  18. Reduced momentum compaction p =0.049, Qz = 0.042 => l = 12mm Luminosity improvement plan

  19. Longitudinal emittance • Element M inserted in ring opposite IP • Then l = 12mm => Qs= 0.049 or Qs =0.089 => l = 7.3mm Luminosity improvement plan

  20. Reduced momentum compaction optics Luminosity improvement plan

  21. Reduced momentum compaction optics Injection Pretzel must be constrained so that electrons closed orbit is near injection point Luminosity improvement plan

  22. Summary • Reduction in energy dependence with anti-solenoid  25 - 40% increase in luminosity at low current Installation January 2006 • Optics with reduced momentum compaction promises payoff at higher current and subject of ongoing investigation Caution: If we are successful reducing 0 current beam size and increasing limiting tune shift then we become more sensitive to RF phase noise Residual coupling Vertical dispersion power supply ripple, etc. Luminosity improvement plan

  23. Wiggler Beam Measurements • Injection 1 sc wiggler (and 2 pm CHESS wigglers) -> 8mA/min 1/ = 4.5 s-1 6 sc wiggler -> 50mA/min 1/ = 10.9s-1 Luminosity improvement plan

  24. Wiggler Beam Measurements6 wiggler lattice • Injection 30 Hz 68mA/80sec 60 Hz 67ma/50sec Luminosity improvement plan

  25. Wiggler Beam Measurements • Single beam stability 6 sc wigglers 2pm + 1 sc wigglers 1/ = 10.9s-1 1/ = 4.5 s-1 Luminosity improvement plan

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