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Summary of Accelerator Sessions

Summary of Accelerator Sessions. M. Biagini for the Accelerator Team SuperB XV Workshop Caltech, CA, Dec. 14-17 2010. Workshop Talks. IBS (Demma) E-cloud instability (Demma) Synchrotron light properties from SuperB (Wittmer) Feedbacks (Drago) Geological survey @ LNF (Tomassini)

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Summary of Accelerator Sessions

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  1. Summary of Accelerator Sessions M. Biagini for the Accelerator Team SuperB XV Workshop Caltech, CA, Dec. 14-172010

  2. Workshop Talks • IBS (Demma) • E-cloud instability (Demma) • Synchrotron light properties from SuperB (Wittmer) • Feedbacks (Drago) • Geological survey @ LNF (Tomassini) • Second order momentum compaction (Novokhatski) • Site committee document (Raimondi) • Spin tracking in LER (Monseu) • LET studies @ DIAMOND (Liuzzo) • Vibration studies (Bertsche) • Vibration measurements @ LNF (Brunetti) • Backgrounds studies (Sullivan, Perez) • IR coupling correction without solenoid (Nosochkov) • Wakefields in the IR (Weathersby) • QD0 design/prototype work (Paoloni) Mike’s summary

  3. CDR2 - Accelerator • Accelerator part of CDR2 updated with: • New beam-beam scan (Chap. 8) • Dynamic aperture (Chap. 6) • Possible synchrotron light beamlines (Chap. 18)

  4. e-cloud instability in HER(Simulation code: CMAD, M.Pivi, SLAC) Demma • Tracking the beam (x,x’,y,y’,z,d) in a MAD lattice by 1st and 2nd order transport maps • Apply beam-cloud interaction point (IP) at each ring element • Parallel bunch-slices based decomposition to achieve perfect load balance • Beam and cloud represented by macro-particles • Particle in cell (PIC) code • 3D electron cloud dynamics • The interaction between the beam and the cloud is evaluated at 40 Interaction Points around the SuperB HER for different values of the electron cloud density • The threshold density is determined by the density at which the growth starts

  5. e-cloud induced emittance growth in SuperB HER (V13) Demma vertical emittance horizontal emittance This work would have not been possible without the support of the INFN-NA group (in particular Dr. S. Pardi) that provided access (and assistance) to the SCOPE-GRID Cluster to perform all the parallel simulations presented here Taking into account the effect of solenoids in drift regions, beam cloud interaction evaluated at magnetic regions only. el= 8x1011 e-/m3 el= 9x1011 e-/m3 el= 10x1011 e-/m3 bunch population

  6. Intra Beam Scattering Status Effect of IBS on transverse emittances about 30% in LER and less than 5% in HER, still reasonable if applied to lattice natural emittances values Interesting aspects of the IBS such as its impact on damping process and on generation of non Gaussian tails may be investigated with a multi-particle code being developed: Benchmarking with conventional IBS theories gave good results Preliminary FORTRAN (faster!) version of the code produced: Remaining features are going to be included very soon Started collaboration with M. Pivi (SLAC) to include the IBS in CMAD (parallel, faster) Started studies on full lattice (including coupling and errors) Demma

  7. Multi-particle tracking of IBS in LER NTurn=10000 (≈10 damping times) MacroParticleNumber=10000 sz=5.0*10-3 m dp=6.3*10-4 tx = 100-1 * 0.040 sec ty = 100-1 * 0.040 sec ts = 100-1 * 0.020 sec ex=1.8*10-9 m ey=0.25/100*ex Mathematica vs Fortran implementation of the IBS multi-particle tracking code. The Fortran version is more then 1 order of magnitude faster!

  8. Second order momentum compaction • When a1 is very small the 2° order a2 may play a role in the longitudinal beam dynamics, good or bad, depending on its sign • There is no instability threshold for a positive value of a2 • It is necessary to check that a2 for Super-B has the right sign, or is < 0.05 at least, if positive a2< 0, beam stable a2> 0, beam unstable Novokhatski

  9. Strong Head –Tail Instability Novokhatski Example for PEP-II, high current, LER

  10. Bunch-by-bunch feedback upgrade During last month all the 6 DAFNE feedback have been upgraded VFB – new 12 bit iGp systems with larger dynamic range and software compatibility with the previous version LFB - completelynew systems in place of the old systems designed in 1992-1996 in collaboration with SLAC/LBNL: fe/be analog unit connected to iGp-8 as processing unit HFB: upgrade hw/sw of the iGp-8bit system already used Epics server upgraded to the last version of LINUX New front-end/back-end analog unit used in the longitudinal feedbacks Drago

  11. Bunch-by-bunch feedback improvements Drago • Larger dynamic range  system more flexible • Fast and easy back-end timing in the trasverse or longitudinal systems • “Bunch cleaning” function can be used to “kick out” a specific bunch or bunch pattern • Better performances, more sophisticate software, simpler hardware

  12. Synchrotron light properties @ SuperB Wittmer • Comparison of brightness and flux from bending magnets and undulators for different energies dedicated SL sources & SuperB HER and LER • Assumed undulators characteristics as NSLS-II • Synchrotron radiation generated with both HER and LER compete very well with state of the are dedicated lighsources in operation, construction and design • The lattices are already well optimized with respect to source point parameters. Only small gains still possible Brightness from Bends Flux from Bends

  13. Synchrotron light from undulators HER @ 4.5 GeV may improve if ex/2 Wittmer Brightness from Undulators Flux from Undulators

  14. Possible beam lines layout Wittmer

  15. Zgoubi tracking studies for Invariant Spin Field Monseu 100 Turn 1000 Turn A method to study high order spin dynamics is being implemented with Zgoubi tracking code PRELIMINARY RESULTS ON CONVERGENCE STUDY • Based on «stroboscopic averaging» • Studies to prove convergence in a reasonable time • Probably will need parallelization for computer speed 2500 Turn 5000 Turn

  16. Site & layout Tomassini • Second campaign of geological survey was completed last July • Second campaign of ground motion measurements was completed last October (see L. Brunetti talk) • Definition of parameters site choice (see Raimondi talk)

  17. Collider hall Damping ring

  18. Second campaign of Geological survey On last July the second campaign of geological prospection was completed at LNF. 4 additional holes of different dept have been bored in the points reported below and marked by a blue arrow. Each hole was lined with a plastic pipe with an inner bore of about 70mm. 40m 50m 40m 50m 40m 50m 30m 1st campaign 40m 2nd campaign

  19. Site Committee (Di Fabrizio, Esposito, Popolizio, Raimondi, Seeman, Tomassini) Raimondi • Document on requirements for site choice • Site layout and geology: • Dimensions • Flatness and slope • Geology • Ground stability • Site conventional facilities: • Buildings • Electric power • Civil construction • Cooling water • Existing conventional facilities • Logistic • Site general requirements

  20. Low Emittance Tuning @ Diamond Liuzzo • LET procedure studied for SuperB applied to the DIAMOND SL source (Rutherford) • Modified to include BPM tilt errors in DIAMOND • Two MD shifts (Nov. 23th, Dec. 7th) • Procedure very fast compared with present DIAMOND LET procedure (LOCO code) • Very good results up to now (emittance coupling measured after correction 0.23%, rms Y-dispersion about 600 m) but need more work on code and MD shifts • Need to implement correctors tilts

  21. CFS Correction with Skew Quadrupoles DY≈ 600 μm Coupling 0.23%

  22. Accelerator Board Comments • Site: • Make a technical determination of shielding requirements • Investigate a larger foot print with more x-ray lines • Discuss “medium constraint” on nearby park-historical situations • Near term technical work (site independent issues): • Vacuum design • Magnet designs • RF configuration • Support designs • Control system

  23. Accelerator Board issues for the next 6 months • Assemble a design/construction team • What is the project management structure? • Determine how to hire people • Determine how SLAC and US will contribute to the accelerator • What is needed for the TDR? Still the same? • What is the design of a full SR facility? Plan now? • How does the accelerator fit into the “ERIC” process? • How does the accelerator team participate in the site selection process?

  24. Near term TDR Activities MDI activites (DCH inner radius, W shield) QD0 design and tests IR QDF design Vibration sensors Cryostat design Spin rotator design Vacuum systems(bellows, extruded chambers, pumps, flanges) Instrumentation (BPMs, emittance measurements, polarization) Polarimetry Tunnel layout Injection system Low level RF Cavity coupler box upgrade New PEP-II element list RF power supplies Magnet supports Review cost estimates

  25. Thank you • I wish to thank all the contributors that in the past 5 years have kept SuperB alive... The SuperB Accelerator Team... Many are missing in the following... Sorry!

  26. Italian Team @ Caltech

  27. Merry Christmas !!!!!

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