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CESR-c Status

CESR-c Status. -Operations/Luminosity December/January vs September/October Machine studies and instrumentation Simulation and modeling. Peak Luminosity. Specific Luminosity. Integrated Luminosity. Machine Studies/Instrumentation. Horizontal separator tilt

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CESR-c Status

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  1. CESR-c Status • -Operations/Luminosity • December/January vs September/October • Machine studies and instrumentation • Simulation and modeling D. Rubin - Cornell

  2. Peak Luminosity D. Rubin - Cornell

  3. Specific Luminosity D. Rubin - Cornell

  4. Integrated Luminosity D. Rubin - Cornell

  5. D. Rubin - Cornell

  6. D. Rubin - Cornell

  7. Machine Studies/Instrumentation • Horizontal separator tilt Level measurements, tilt < 0.3 mrad, negligible effect on orbit But what about plate/vacuum can alignment ? Beam based measurement, tilt ~ 4 mrad • Tune spread - Safe operating space in tune plane narrows with increasing current - Tune spread reduces current limit - Instability in magnet power supply? - Modify feedback circuit for all quad choppers, no effect on tune spread D. Rubin - Cornell

  8. D. Rubin - Cornell

  9. Machine Studies/Instrumentation • Orbit stability Evidence of vertical orbit motion in - synchrotron radiation light monitor - orbit measurement with beam position monitors - turn by turn data at IR beam detectors - fast luminosity monitor Sources of vertical motion might include - Instability in quadrupole power supplies (Q48,49) - of vertical separator plate voltages - of skew quadrupole currents, SCIR skew quads D. Rubin - Cornell

  10. Machine Studies/Instrumentation • Continuously monitor electron positron orbit difference - BPM electronics and software under development “true” differences with arbitrary time scales - Better monitoring of suspect elements D. Rubin - Cornell

  11. Machine Studies/Instrumentation • Luminosity monitor - Luminosity signal is compromised by lost particles when electron lifetime is poor - Detector segmentation provides means for correction DSP software begin developed - Plan to implement “true” calibration - Software also in the works to enable bunch by bunch luminosity measurement D. Rubin - Cornell

  12. Machine Studies/Instrumentation • Knobs to control differential coupling using skew sextupoles 3 new sextupoles installed • Demonstrated capability to measure with turn by turn BPM data, coupling at IP - And “good” luminosity corresponds to measured flat beam at IP • Developing IR BPM calibration and software to implement as part of coupling correction procedure D. Rubin - Cornell

  13. SCMATING 2 = -160 D. Rubin - Cornell

  14. SCMATING 2 = -120 D. Rubin - Cornell

  15. SCMATING 2 = -70 D. Rubin - Cornell

  16. SCMATING 2 = -40 D. Rubin - Cornell

  17. SCMATING 2 = -120 D. Rubin - Cornell

  18. SCMATING 2 = -70 D. Rubin - Cornell

  19. SCMATING 2 = -40 D. Rubin - Cornell

  20. SCMATING 2 = 70 D. Rubin - Cornell

  21. SCMATING 2 = 40 D. Rubin - Cornell

  22. D. Rubin - Cornell

  23. Beam beam simulation • Semi strong-strong simulation • Machine model includes all individual guide field elements • (RF, wigglers, separators,…) and nonlinearities • radiation, damping, crossing angle, pretzel, parasitic • interactions, … • Weak beam ~ 200 macroparticles • Track for 200,000 turns • Use weak beam size to update strong beam -> Beams have equal charge and size Strong beam is fixed in space D. Rubin - Cornell

  24. Beam beam simulation 1.89 GeV/beam D. Rubin - Cornell

  25. D. Rubin - Cornell

  26. Simulation -Real wigglers, -Linearized wigglers, -Pretzel off/real wigglers No significant difference In low current behavior D. Rubin - Cornell

  27. D. Rubin - Cornell

  28. Machine Studies/Instrumentation (cont) • More bunches -10 bunches/train, 2 sets of 5 displaced by 2ns -Calculation of optical distortion due to parasitic additional interactions indicates small effect -Established injection of single 10 bunch train -Collisions of 2,3 electron bunches with 10 bunch positron train • Alternatively 9 bunches/train 1 set 5 and 1 set 4 displaced 6ns under study D. Rubin - Cornell

  29. Simulation plan • Lattice with distributed radiation excitation • Dependence • differential offset/angle at IP • coupling/ differential coupling • sextupoles/chromaticity • tune spread Thanks to CLEO collaborators Minnesota and Illinois and CHESS for making computers available and for help getting started D. Rubin - Cornell

  30. D. Rubin - Cornell

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