SuperB mini-Workshop Oxford 18-19th May 2011 Summary of the parallel session on Accelerators R. Bartolini Diamond Light Source Ltd and John Adams Institute, University of Oxford XVII SuperB and kick-off Meeting, Elba 29 th May 2011

Oxford SuperB mini-workshop Organising committee A. Seryi JAI Oxford R. Bartolini JAI Oxford A. Bevan QMUL

Goal of the workshop Inform UK accelerator and detector community about the latest development on superB Explore the area of interest of the accelerator and detector community where possible contributions can be made to the SuperB Bring community together assess and possibly foster interest in SuperB Get some indications from STFC about possible involvment in super B (£) Discuss the way forward

Areas of interest emerged from the parallel session on accelerators Low emittance tuning Linear optics correction Nonlinear optics correction 3 talks Impedance computation Single bunch effects Multi bunch effect Codes development 2 talks Diagnostics and feedback systems 2 talks + A. Drago’s talk Hardware Magnets and wigglers 1 talk

Low emittance tuning Linear optics correction LOCO (ORM-based tools) very succesfull at light sources (beta-beat < 1%, V emittance 2 pm or less) BPM calibration with normal modes and mode-II disperison correction 14 pm at CesrTA Genetic algorithms to reduce knobs in ORM base methods Spectral lines and coupling resonances ESRF 4.4 nm Dispersion and coupling free steering (Dafne-Diamond-SLS) comparison with LOCO ongoing at Diamond Possibility to extend comparison to all these techniques at Diamond (within limits RPW)

Linear optics correction with LOCO (R. Bartolini) Hor.  - beating < 1% ptp Ver.  - beating < 1 % ptp Very good control of the linear optics with LOCO Emittance [ ] (2.75) nm Energy spread [1.1e e3] (1.0e-3) Coupling correction to below 0.1% V beam size at source point 6 μm V emittance 2.2 pm

Calibration of BPMs from normal modes (A. Wolski) b1b1 b2b2 b3b3 b4b4 u v The impact of systematic BPM errors is one of the major issues with ultra-low emittance tuning. I shall describe a technique for calibrating the BPMs from normal mode beam motion,  procedure for ultra-low emittance tuning. calibrate the BPMs from observation of normal mode oscillations, to read the beam coordinates on the normal mode axes; use corrector elements skew quadrupoles to minimise the mode II dispersion in the dipoles.

Correction of mode-II dispersion (A. Wolski) The calibrated BPMs can be used to measure directly the mode II dispersion: this is model independent. The skew quad strengths needed to correct the mode II dispersion are calculated using a response matrix computed using a machine model. Experimental tests at CesrTA

LET minimising the knobs (J. Jones) As a first pass to investigate the minimum number of required skew quads we use a global non-linear optimiser Vary the number of skew quads, then use a Nelder-Mead Simplex to optimise on the extracted vertical emittance to less than 20nm Solutions for LET –All methods rely on the creation of Response Matrices. Closed Orbit Correction – Uses up to 690 BPMs and up to 690 correctors to minimise orbit in the ring. Vertical Dispersion Correction – Correct using skew quads. Can use up to 240 skew quads and up to 690 BPMs Coupling Correction –Uses up to 240 skew quads and up to 690 BPMs. –Vert. Dispersion and Coupling correction are performed together, with an optimised weighting between the two corrections! –For cost reasons, it is desired to minimise the number of BPMs and correctors.

Low emittance tuning at Diamond for SuperB Last year results on low emittance tuning and the achievement of a vertical emittance of 2.2 pm have sparked quite some interest from the Damping ring community (CLIC and ILC) and from the Super B In collaboration with the SuperB team (P. Raimondi,. M. Biagini, S: Liuzzo) Diamond has been used as a test-bed for new techniques for low emittance tuning based on dispersion free steering and coupling free steering. 4 MD shifts at DLS November - February New JAI PhD student to start in October

Combining the complementary information from FM and spectral line should allow the calibration of the nonlinear model and a full control of the nonlinear resonances FLS2010, SLAC, 02 March 2010 Nonlinear dynamics correction (R. Bartolini) Closed Orbit Response Matrix from model Closed Orbit Response Matrix measured fitting quadrupoles, etc Linear lattice correction/calibration LOCO Spectral lines + FMA from model Spectral Lines + FMA measured fitting sextupoles and higher order multipoles Nonlinear lattice correction/calibration Nonlinear calibration and correction Frequency Maps and amplitudes and phases of the spectral line of the betatron motion can be used to compare and correct the real accelerator with the model

Vacuum chamber design and single bunch instability modelling (M. Korostelev) Detailed design and wakefield computation for various structures Parallel Tracking code for single bunch longitudinal instabilities

Long range wakefields and multibunch instabilities modelling (K. Hock) Resistive Wall computation with NEG coating Multibunch macroparticle tracking code for the simulation of transverse multibunch instabiltiies Multibunch, multiturn wakes + full description of lattice Highlighted effect of injected beam into the stored beam

Feedback systems (G. Christian) Feedback at the IP (FONT) and multibunch feedback system Tests of FONT5 on a 3 bunch train at ATF2

Diagnostics (S. Boogert)

Magnets, Wigglers and Undulators (J. Clarke) Conventional magnets Dipoles, Quadrupoles, Sextupoles,... Kickers & Septums DC, AC, & Pulsed Recent projects Diamond, ALICE, EMMA Wigglers and undulators In-vacuum, Apple-II Permanent magnets Superconducting, SC helical Recent projects include SRS, Diamond, ALPHA-X, ALICE, ILC Codes for magnet modelling Opera 2D, Opera 3D, Tosca,Elektra CST EM Studio (3D) RADIA (3D) - very good for PM undulators

Code developments (many speakers) Large body of experience in ASTeC using GAs for Non-linear optimisation of Storage Rings (DIAMOND) Injector Optimisation for 4 th generation light sources (NLS) Working point optimisation for next generation light sources (NLS) Similar expertise at JAI Oxford and Diamond Simulations at JAI RHUL

Summary What could the UK bring to Super-B? (1) Broad variety of relevant expertise in accelerator science and technology: –Large scale electron storage rings Diamond –Test facilities ALICE –In the universities and accelerator Institutes MDI, FF, optics … Need to increase the level of interest on SuperB both on accelerator and Detectors

Summary (II) Discussion of way forward Formalise collaboration(s) short term long term (when superB is established as an ERIC) Possibility for SuperB to pay for contracts, PDRA *based in Italy* and for short-to-mid visits in Italy MOU similar to those in place with Orsay Areas of interest (mostly identified at this workshop) Breakdown of tasks (SuperB to tell priorities) Assign tasks (UK, Frascati, SLAC, other labs) Coordinate the work within the area of interest Establish a UK SuperB Accelerator Physics Working Group Thank you for your attention