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

Workshop Talks IBS (Demma) E-cloud instability (Demma) Synchrotron light properties from SuperB (Wittmer) Feedbacks (Drago) Geological LNF (Tomassini) Second order momentum compaction (Novokhatski) Site committee document (Raimondi) Spin tracking in LER (Monseu) LET DIAMOND (Liuzzo) Vibration studies (Bertsche) Vibration 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

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

Tracking the beam (x,x’,y,y’,z,d) in a MAD lattice by 1 st and 2 nd 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 e-cloud instability in HER (Simulation code: CMAD, M.Pivi, SLAC) Demma

e-cloud induced emittance growth in SuperB HER (V13) Taking into account the effect of solenoids in drift regions, beam cloud interaction evaluated at magnetic regions only.  el = 8x10 11 e-/m 3  el = 9x10 11 e-/m 3  el = 10x10 11 e-/m 3 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 vertical emittancehorizontal emittance bunch population Demma

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

Multi-particle tracking of IBS in LER  z =5.0*10 -3 m  p=6.3*10 -4 e x =1.8*10 -9 m e y =0.25/100*e x t x = * sec t y = * sec t s = * sec MacroParticleNumber=10000 NTurn=10000 (≈10 damping times) Mathematica vs Fortran implementation of the IBS multi-particle tracking code. The Fortran version is more then 1 order of magnitude faster!

Second order momentum compaction When  1 is very small the 2° order  2 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  2 It is necessary to check that  2 for Super-B has the right sign, or is < 0.05 at least, if positive  2 < 0, beam stable  2 > 0, beam unstable Novokhatski

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

Bunch-by-bunch feedback upgrade During last month all the 6 DA  NE feedback have been upgraded VFB – new 12 bit iGp systems with larger dynamic range and software compatibility with the previous version LFB - completely new systems in place of the old systems designed in 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

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 Bunch-by-bunch feedback improvements Drago

Synchrotron light SuperB 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 Wittmer Brightness from Bends Flux from Bends

Synchrotron light from undulators Wittmer Brightness from UndulatorsFlux from Undulators 4.5 GeV may improve if  x /2

Possible beam lines layout Wittmer

Zgoubi tracking studies for Invariant Spin Field A method to study high order spin dynamics is being implemented with Zgoubi tracking code Based on «stroboscopic averaging» Studies to prove convergence in a reasonable time Probably will need parallelization for computer speed PRELIMINARY RESULTS ON CONVERGENCE STUDY 100 Turn1000 Turn 2500 Turn5000 Turn Monseu

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) Site & layout Tomassini

Damping ring Collider hall

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. 50m 40m 30m 50m 40m 1 st campaign 2 nd campaign

Site Committee (Di Fabrizio, Esposito, Popolizio, Raimondi, Seeman, Tomassini) 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 Raimondi

Low Emittance Diamond LET procedure studied for SuperB applied to the DIAMOND SL source (Rutherford) Modified to include BPM tilt errors in DIAMOND Two MD shifts (Nov. 23 th, Dec. 7 th ) 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  ) but need more work on code and MD shifts Need to implement correctors tilts Liuzzo

D Y ≈ 600 μm Coupling 0.23% CFS Correction with Skew Quadrupoles

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

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?

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

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

Merry Christmas !!!!!