Summary of Accelerator

1. Summary of Accelerator M. Biagini for the SuperB Accelerator Team SuperB II Collaboration Meeting LNF, December 13-16, 2011

2. Accelerator sessions • Welistened to 29 talks (excluding 2 MDI sessions), no time to report all, I apologize… • Asreported by Levichev in the opening talk westillhave some open questions in beamdynamics, hopefully to be solved in the next 3 months • A pre-workshop on the Control System !CHAOS washeld on Monday, talks on http://agenda.infn.it/conferenceDisplay.py?confId=4322

3. Parameters Evolution • Parameters substantially unchanged since 1 year • Minor changes from ARC Cells modifications: • lower emittance and shorter ARCs from improved 3pi Cell Design • 6 SL lines insertions added: • drift space increased for ID • emittance increased • Overall emittance decreased by about 10% • Ring length decreased from 1250m to 1200m • Machine and beam parameters are quite close to self consistency • Design could be frozen soon and TDR phase could begin correspondly Raimondi

4. SuperB @ Tor Vergata (S. Tomassini) Beamlines Injection complex

5. LER & HER rings IP • Circumference 1195 m • Horizontal separation of arc ~2 m • Vertical separation of RF section 0.9 m • Dimension sizes of rings 416 m x 342 m FF Spin Rotator 3 ID cells 3 ID cells Injection section RF section

6. Scheme of ring separation αtilt=2.6 mrad Vertical separation 0.9 m

7. Some magnets design

8. Conclusions on Lattice • The geometry of rings is closed. The circumferences are equal • Radial distance between rings is ~2 meters • Vertical separation is 90 cm • Injection cells are inserted • Cells for IDs are inserted • Radiation parameters of arc cells are tuned • Matching of optics is made • Correction of chromatic functions is made • Preliminary design of some magnetic elements was done by P. Vobly

9. Crab Sexts Influence on DA Switching on crab sextupoles drastically reduces the dynamic aperture (still is about ±20 sx, 200 sy, injection requirement 12 sx) All nonlinearities All w/o Crab Sexts All w/o Kinematics and Fringes More work needed for optimization of nonlinearities Piminov

10. Low Emittance Tuning, applications Liuzzo Comparison between LET and LOCO Measurements at Diamond Decay mode 900 bounches 150 mA H emittance [nm] Lifetime [h] Current[mA] Coupling [%] Initial conditions 21.1 h Couplingestimated from lifetime: εy =1.6 10-12 m rad (LET) After 2 LOCO iterations with skewquad and quad 5.9 h 5.5 h After 4 LET iterations with skewquad FinalLifetimemeasurementspreformedafterinjection LOCO LOCO LET BPM Tilt estimate by LOCO S.M.Liuzzo PhD at LNF-INFN

11. Measurements at SLS Beam size measurement for 3 subsequent correction performed using only VERTICAL STEERERS Top-up mode 400 mA Normal user operations Best observed σy=6.8 μm SLS best σy= 4.9 μm isobtianedusingskewquadrupoles 400 μm residual vertical orbit. Testedalso Horizontalcorrection and Skewquadrupolescorrection, butstill work is in progress.y S.M.Liuzzo PhD at LNF-INFN

12. First tolerance tests for HER V16 50 random sets, correcting with LET for 2 iterations after 3 orbit pre-correction iterations 4.4 pmrad before S.M.Liuzzo PhD at LNF-INFN

13. LET with Normal Modes BPM Calibration Normal mode BPM calibration provides a fast and (at least in simulation) very effective technique for ultra-low emittance tuning in storage rings Initial results at CesrTA look encouraging, but there is still some work needed to understand the full practical potential b3 v b4 u b1 b2 We can obtain the components of the calibration matrix from correlation plots of the button signals during normal mode beam excitation… Wolski

14. e-cloud buildup in HER Dipoles Demma By=0.3 T; =95%SEY=1.1 e- density averaged over the beam chamber e- density at center of the beam pipe 10 X beam sizes th= 1012 [e-/m3] Snapshot of the electron (x,y) distribution “just before” the passage of the last bunch

15. e-cloud clearing electrodes in DAFNE Drago Very positive results: vertical beam dimension, tune shift and growth rates clearly indicate the good behaviour of these devices, which are complementary to solenoidal windings in field free regions Beam loss above this current if no feedbacks

16. IBS in SuperB Damping Ring Demma Radiation Damping + Quantum Excitation Radiation Damping + Quantum Excitation + IBS Effect of IBS on the damping process is very small

17. CSR in Damping Ring Zhou For both SuperB and SuperKEKB Coherent Synchrotron radiation instability is not a problem in topping up mode, threshold being about 3 times the bunch population

18. Polarization Koop

19. Injection Complex Guiducci • Present status • Parameters and site layout selected • Layout and parameters of the system components defined • Beam dynamics evaluation started • Remaining work: • Baseline decision on electron source: direct injection or damping ring • Baseline decision on positron source: conversion at low energy (.6 GeV), L-band linac for capture and acceleration up to 1 GeV (or a combination of S and L band) • Transfer lines layout and composition follows • Systems ready for TDR • Damping ring • Main linac

20. RF layout Boni

21. Injection tracking with bb Average over (1 ÷ 100) turns Average over (30001 ÷ 30100) turns Average over (4001 ÷ 4100) turns No beam-beam Crab = 1 Crab = 0.5 Crab = 0 No beam-beam Crab = 1 Crab = 0.5 Crab = 0 No beam-beam Crab = 1 Crab = 0.5 Crab = 0

22. SuperKEKB

23. Polarized electron source • A design choice is needed: electrons injection with/without passing through the DR • Is it possible to produce and accelerate to 4.18 GeV polarized electrons with ~ 1 nC charge, low emittance and small energy spread? • Very preliminary beam dynamics study • Further checks are needed: • Very important to define the charge and bunch length needed/feasible at gun exit

24. Positron Source Variola What we are doing: 1) Study of the extension of the drive beam to 1 and 1.5 GeV (to study a full 3 GHz solution). Optimization of the production target and of the capture system 2) Study of the TM 020 L band cavity 3) Costing of the L Band solution What is planned: 1) Hybrid solution (L and S band) 2) Coupling correction 3) Matching to the TL 4) Injection simulations Manpower needed to deliver the system estimated in 38 FTE

25. Started WBS for IS

26. Feedbacks Drago

27. Timing and synchronization Drago Bellato

28. R&D on Controls (!CHAOS) Bisegni • Thisactivityattractedinterest from severalother INFN structuresand Universities

29. SuperB not «just a collider»

30. Brilliance SuperB vs ESRF (and ESRF upgrade) Bartolini Used U23 of ESRF ID27 ESRF parameters (4nm) 200 mA 0.7% coupling 2 m undulator ESRF upgrade (4nm) 300 mA 0.3% coupling 4 m undulator SuperB (2nm) 500 mA 0.7% coupling 2m undulator SuperB ESRF upgrade ESRF 2nd superB meeting, Frascati 13th December 2011

31. Clearunderstandingof the heatload managemente.g. optics design, distances, material, coolingsystems, etc Orbit and optics control: the orbit and optics must be controlled at all the source points not just at the interaction point Stability: Orbit variation up to 100 Hz or more must be compensated. This requires a FOFB. Additional variation when moving the IDs gap Thermal load variation generate BPM block movement of the order of 10-15 um in decay mode at 150 mA at Diamond. The variation heat load of a 6 GeV 0.7 A beam will be huge. Top uprequired for stability Lifetime – Touschek lifetime requires large momentum aperture. (3-4%). True even in Top-Up. Watch alpha_2. However when parasitic to the collider the lifetime is dominated by collisions (beam beam bremsstrahlung). High current operation: Collective effects stronger in B factories, but will be made more acute if in-vacuum ID and narrow gap vessels are to be introduced. IBS not a problem Comments on the compatibility of light source / collider

32. First considerations from SLS community Giannessi • Questions: • Can the synchrotron radiation facility be fully compatible with the normal operation of the collider ? • High average current –reduce current through bunch # reduction? • Optimization of the ring lattice for SR – trade between current and stability • Relatively modest number and length of straight sections • Time sharing ? • At the end of its life as a collider the ring could be modified optimized to accommodate a higher number of beamlines and the lattice could be improved in terms of average current / brightness. • Time span: a decade ? A ring with the specs of SUPERB, will be still state of the art at that time ? • Should we look for a specialization in the field of applications of SuperB as LS, e.g. Time resolved applications ? • Free electron lasers ? • Suggestion: Next workshop, have a session devoted to SL.

33. Quintieri MC simulations of different targets for different particles production

34. Summary of the summary… • Lattice «close» to be frozen, some more work needed on beam dynamics issues (see Levichev opening talk) • We have some system «close» to TDR phase • Some strategical design choices still to be taken (ex. in injection system) • Most important issues to solve in the next months have been identified • R&D on control system started • Beam dynamics studies in the injection system started, collective effects in the DR are Ok • R&D on new bunch-by-bunch feedback very positive (test at DAFNE) • Tests on e-cloud suppression electrodes at DAFNE successfull

35. …summary of the summary • Organization of the accelerator structure was discussed, more to do • Synchrotron Light Italian community started to consider SuperB properties for SL users  needs more thoughts on maximum current, operation mode, experiments. Proposal to have a dedicated session at next Collaboration Meeting • MC simulations on the possibility to have a «SuperBTF» started  interest from users • Collaboration with other INFN structures (besides international partners) may help us, needs coordination • We hope Cabibbo Lab will solve management, manpower and money issues soon • Many thanks to all speakears and participants, we are closer than ever to «start» !!