CESR as a Vehicle for ILC Damping Rings R&D Mark Palmer Cornell Laboratory for Accelerator-Based Sciences and Education.
Download ReportTranscript CESR as a Vehicle for ILC Damping Rings R&D Mark Palmer Cornell Laboratory for Accelerator-Based Sciences and Education.
CESR as a Vehicle for ILC Damping Rings R&D Mark Palmer Cornell Laboratory for Accelerator-Based Sciences and Education Outline • International Linear Collider Overview – Preparing for the Engineering Design Report (EDR) – ILC R&D at Cornell • CesrTA Proposal – ILC Damping Rings Overview – Damping Rings R&D Using CESR • • • • • • Concept and Goals Ring Modifications Parameters and Experimental Reach Collaborators Damping Rings Projects Schedule • Synergies with Other Parts of the CLASSE Program • Acknowledgments and Conclusion November 7, 2015 CesrTA Seminar 2 The ILC • Basic Numbers – – – – – • Machine Configuration 500 GeV – upgradeable to 1 TeV 14 kHz Collision Rate Luminosity: 2x1034 cm-2s-1 31 km end-to-end length 31.5 MV/m SRF cavities – Helical Undulator polarized e+ source – Two 6.7 km damping rings in central complex – RTML running length of linac – 11.2 km Main Linac – Single Beam Delivery System – 2 Detectors in Push-Pull Configuration • 16K Cavities • 2K Cryostats November 7, 2015 CesrTA Seminar 3 ILC Program • ICFA Release of Reference Design Report (RDR) – – – – Release Date: February 8, 2007 Draft available at: http://www.linearcollider.org Press Release: http://www.interactions.org/cms/?pid=1024912 RDR Cost Estimate (accelerator complex): • $1.8bn site costs (eg, tunneling) • $4.9bn technology and component costs • 13K person-years of effort (personnel costs not in above numbers) • Start of the Engineering Design Phase – Engineering Design Report (EDR) in early 2010 – Complete critical R&D (eg, SRF cavity gradient yield for ML, electron cloud and fast kicker technology for DR) – Basic engineering design November 7, 2015 CesrTA Seminar 4 ILC R&D at Cornell – Damping Rings – SRF – Detector (TPC) • R&D Efforts – Helical Undulator Polarized Positron Source – Ring-to-Main Linac – Low Emittance Transport (RTML and Main Linac) November 7, 2015 • Also management contributions CesrTA Seminar 5 ILC Damping Rings R&D Overview • Damping Rings – – – – – • Simulation Electron Cloud and Ion Effects Technical Systems (wigglers, kickers, instrumentation…) CesrTA Development BCD and RDR Support J. Urban J. Alexander, M. Billing, G. Codner, J. Crittenden, G. Dugan, M. Ehrlichman, D. Hartill, R. Helms, R. Holtzapple, J. Kern, Y. Li, R. Meller, M. Palmer, D. Rice, D. Rubin, D. Sagan, L. Schachter, J. Shanks, E. Tanke, M. Tigner, J. Urban (note: 5 students) November 7, 2015 CesrTA Seminar 6 Outline • International Linear Collider Overview – Preparing for the Engineering Design Report (EDR) – ILC R&D at Cornell • CesrTA Proposal – ILC Damping Rings Overview – Damping Rings R&D Using CESR • • • • • • Concept and Goals Ring Modifications Parameters and Experimental Reach Collaborators Damping Rings Projects Schedule • Synergies with Other Parts of the CLASSE Program • Acknowledgments and Conclusion November 7, 2015 CesrTA Seminar 7 The ILC Damping Rings Beam energy 5 GeV Circumference 6695 m RF frequency 650 MHz Harmonic number 14516 Injected (normalised) positron emittance 0.01 m OCS v6 TME Lattice Extracted (normalised) emittance 8 μm × 20 nm Extracted energy spread <0.15% Average current 400 mA Maximum particles per bunch 2×1010 Bunch length (rms) 6 mm 9mm Minimum bunch separation 3.08 ns 2 pm-rad geometric emittance 250 km main linac bunch train is “folded” into the DRs Circled items play a key role in our local R&D plans… November 7, 2015 CesrTA Seminar 8 RDR Version of ILC DR Layout e- ring circulates in opposite direction in same central tunnel November 7, 2015 CesrTA Seminar 9 RDB S3 Very High Priorities • • • • • • • • • • • Lattice design for baseline positron ring Lattice design for baseline electron ring Demonstrate < 2 pm vertical emittance Characterize single bunch impedance-driven instabilities Characterize electron cloud build-up Develop electron cloud suppression techniques Develop modelling tools for electron cloud instabilities Determine electron cloud instability thresholds Characterize ion effects Specify techniques for suppressing ion effects Develop a fast high-power pulser November 7, 2015 CesrTA Seminar 10 Moving to a Single Positron DR M. Pivi ILCDR06 No additional suppression techniques assumed in dipoles and wigglers! Cloud density near (r=1mm) beam (m-3) before bunch passage, values are taken at a cloud equilibrium density. Solenoids decrease the cloud density in DRIFT regions, where they are only effective. Compare options LowQ and LowQ+train gaps. All cases wiggler aperture 46mm. November 7, 2015 CesrTA Seminar 11 Suppressing Electron Cloud in Wigglers Submitted to PRSTAB Design & test of impedance is under the way, test in PEPII Dipole & CESR Wiggler Strip-line type 10 Wire type 10 average density, long train central density, long train average density, bunch train, -100V central density, bunch train, -100V average density, bunch train, 200V central density, bunch train, 200V 13 12 -3 e (m ) 10 14 10 10 10 stripline position 11 10 9 0 20 40 60 80 100 120 Bunch ID Suetsugu’s talk Calculation of the impedance ( Cho, Lanfa) Strip-line type November 7, 2015 Wire type CesrTA Seminar L. Wang ILCDR06 12 ILCDR R&D Issues and CesrTA • Some High and Very High Priority R&D Items that Can Be Addressed at CesrTA… – Electron Cloud • • • • Growth in quadrupoles, dipoles, and wigglers Suppression in quadrupoles, dipoles, and wigglers Instability thresholds and emittance growth in the positron damping ring This issue has become more significant due to the decision to employ a single positron damping ring – Ion Effects • Instability thresholds and emittance growth in the electron damping ring – Ultra-low Emittance Operation • • • • Alignment and Survey Beam-based Alignment Optics Correction Measurement and Tuning – Fast (single bunch) high voltage kickers for injection/extraction • >100 kV-m of stripline kick required • <6 ns wide pulse into a 0.3 m long stripline so as not to perturb neighboring bunches in the damping ring – Development of 650 MHz SRF System November 7, 2015 CesrTA Seminar 13 CesrTA Concept • Reconfigure CESR as a damping ring test facility – Move wigglers to zero dispersion regions for low emittance operation – Open up space for insertion devices and instrumentation • Provide an R&D program that is complementary to work going on elsewhere (eg, KEK-ATF) • Provide a vehicle for: – R&D needed for EDR decisions (EDR R&D completion by end of 2009 is ILC target) – Operating and tuning experience with ultra-low emittance beams – DR technical systems development • Provide significant amounts of dedicated running time for damping ring experiments November 7, 2015 CesrTA Seminar 14 CesrTA Operating Model • Experimental Model – Collaboration among international researchers (similar to HEP collaborations) – Cornell provides machine infrastructure and support – Cornell provides operations staff • Scheduling Model – Provide multiple dedicated experimental periods each year – Provide sufficient scheduled down time to flexibly upgrade machine and install experimental apparatus – Alternate running periods with CHESS November 7, 2015 CesrTA Seminar 15 CesrTA Ring Modifications • Place all wigglers in zero dispersion regions – Wigglers in L1 and L5 straights can remain in place – Emittance scaling for wiggler dominated ring: 8 x x Cq J x 15k p2 w3 2 • Vacuum system modifications – Electron cloud and ion diagnostics – Synchrotron x-ray dump for high energy operation of part of the wiggler complement • Remove 4 of 6 electrostatic separators • Upgrade instrumentation and diagnostics for planned experiments • Feedback system modifications for 4 ns bunch spacing November 7, 2015 CesrTA Seminar 16 CESR Modifications • Move 6 wigglers from the CESR arcs to the South IR (zero dispersion region around CLEO) – NOTE: this is a recent change in plans • Instrumentation and feedback upgrades November 7, 2015 CesrTA Seminar 17 The South IR South IR Modifications: • Remove CLEO drift chambers • Instrumented vacuum chambers for local electron cloud diagnostics • Eventual test location for prototype ILC damping wiggler and vacuum chambers November 7, 2015 CesrTA Seminar 18 Instrumentation for Ultra-Low Emittance Measurement • Typical Beam Sizes – Vertical: sy~10-12 mm – Horizontal: sx ~ 80 mm (at a zero dispersion point) • Have considered laserwire and X-ray profile monitors – Fast X-ray imaging system (Alexander) • Core diagnostic for CesrTA – high resolution and bunch-by-bunch capability • Plan for integrating systems into CHESS lines • First pinhole camera tests were successful! (see next slide) – Laserwire • CESR-c fast luminosity monitor offers window suitable for laserwire use • Detector potentially could be used for fast segmented readout of Compton photon distribution November 7, 2015 CesrTA Seminar 19 First bunch-by-bunch beam size data in CHESS conditions a Significant CHESS support Signal (ADC Counts) GaAs Detector for X-ray Imaging s= 142 +/- 7 mm Different symbols represent different bunches Fast enough for single bunch resolution November 7, 2015 CesrTA Seminar Pinhole camera setup at B1 hutch Position (mm) NEW: GaAs arrays from Hamamatsu • 1x512 linear array • 25 mm pitch • 1st sample has recently arrived 20 CesrTA Beamsize Monitor Concept • Simple optics – High transmission – 2 keV operation (works for both 2 GeV and 5 GeV) – Hundreds (2 GeV) to thousands (5 GeV) of photons per bunch passage • Explore other detector possibilities (eg, InSb arrays) • Collaboration with CHESS colleagues for optics and device development as well as integration with existing Xray lines zone plate detector 25um Be Multilayer W/C mirrors; q p November 7, 2015 CesrTA Seminar 21 CESR Modifications Summary • How extensive are the modifications? – Significant changes to the South IR (however, certainly no more difficult than a detector and IR magnet upgrade) • Conversion is relatively modest – Core ring modifications will take place in a single down period • Mid-2008 • <3 months duration – Carry out key preparation work between now and April 2008 November 7, 2015 CesrTA Seminar 22 Experimental Reach Baseline Lattice Parameter E Value 2.0 GeV Nwiggler 12 Bmax 2.1 T x 2.25 nm Qx 14.59 Qy 9.63 Qz 0.075 sE/E 8.6 x 10-4 tx,y 47 ms sz (with VRF=8.5MV) 9 mm ac 6.4 x 10-3 tTouschek(Nb=2x1010) >10 minutes November 7, 2015 CesrTA Seminar 23 Tune scans • Tune scans used to identify suitable working points Qx~14.59 November 7, 2015 Qy~9.63 CesrTA Seminar 24 Alternate Optics • Have explored a range of optics for machine transition and physics studies Layout Energy (GeV) Bpeak (T) No. Wigglers Zero current x (nm-rad) CesrTA 2.0 2.1 12 1.8 CESR-c 2.0 2.1 6 6.5 CesrTA 2.0 1.9 12 1.9 CesrTA 2.5 2.1 12 3.2 CesrTA 1.5 1.4 12 1.3 CesrTA 5.0 2.1 6 26 November 7, 2015 CesrTA Seminar 25 Lattice Evaluation • Dynamic aperture – 1 damping time – Injected beam fully coupled • x = 1 mm • y = 500 nm • Alignment sensitivity and low emittance correction algorithms – Simulations based on achieving nominal CESR alignment resolutions Misalignment Nominal Value Quadrupole, Bend and Wiggler Offsets 150 mm Sextupole Offsets 300 mm Quadrupole, Bend, Wiggler and Sextupole Rotations 100 mrad November 7, 2015 CesrTA Seminar 26 Vertical Emittance Sensitivities (Selected Examples) November 7, 2015 CesrTA Seminar 27 Low Emittance Operations • Have evaluated our ability to correct for ring errors with the above lattice Nominal Values – Goal: y~5-10 pm at zero current – Simulation results indicate that we can reasonably expect to meet our targets Correction Type Average Value 95% Limit Orbit Only 10.2 pm 21.4 pm Orbit+Dispersion 3.9 pm 8.2 pm November 7, 2015 CesrTA Seminar 28 IBS Evaluation (2 GeV Baseline Lattice) • Transverse emittance growth for different contributions of coupling and dispersion to the vertical emittance – Baseline lattice – Compare different corrected optics assumptions – 9 mm bunch length • Energy flexibility of CESR and -4 IBS dependence offers a flexible way to study, control and understand IBS contributions to emittance relative to other physics under consideration November 7, 2015 CesrTA Seminar 29 CesrTA Research Directions • Core Efforts – Electron Cloud Growth Studies – particularly in the CESR-c wigglers • Bunch trains similar to those in the ILC DR • Vacuum chambers with mitigation techniques and diagnostics – Ultra low Emittance Operation • • • • Alignment and Survey Beam-based Alignment Optics Correction Measurement and Tuning – Beam Dynamics Studies • Detailed inter-species comparisons (use to distinguish electron cloud, ion and wake field effects) • Characterize emittance growth in ultra-low emittance beams (electron cloud, ion effects, IBS, …) – Test and Demonstrate Key Damping Ring Technologies • Wiggler vacuum chambers, optimized wigglers, diagnostics, … November 7, 2015 CesrTA Seminar 30 Proposal Collaborators Collaborators Institution Topic M. Pivi and L. Wang SLAC Electron cloud studies, wiggler chambers for electron cloud suppression Y. Cai and PEP-II Beam Physics Group SLAC Machine correction and ultra-low emittance tuning A. Reichold and D. Urner Oxford Alignment and survey requirements and upgrades S. Marks and R. Schlueter and M. Zisman LBNL Wiggler chambers for electron cloud suppression C. Celata, M. Furman and M. Venturini LBNL Simulation of electron cloud in wigglers A. Molvik LLNL Electron cloud measurements J. Byrd, S. de Santis, M. Venturini, and M. Zisman LBNL Wiggler and electron cloud and FII studies K. Harkay ANL Electron cloud measurements J. Flannagan, K. Ohmi, N. Ohuchi, K. Shibata, Y. Suetsugu, and M. Tobiyama KEK Electron cloud measurements and simulation P. Spentzouris, J. Amundsen and L. Michelotti FNAL Beam dynamics simulations and measurements A. Wolski Cockcroft Inst. Machine correction and ultra-low emittance tuning R. Holtzapple Alfred Univ. Instrumentation and beam measurements J. Urakawa KEK R&D program coordination L. Schächter Technion-Haifa Electron cloud measurements and analysis Letters of intent from ~30 collaborators for direct work on CesrTA November 7, 2015 CesrTA Seminar 31 CESR-c Wiggler Modifications • Initial vacuum tests in CesrTA • Remove Cu beam-pipe • Replace with beam-pipe having ECE suppression and diagnostics hardware • CU/SLAC/LBNL Collaboration • Prototype Optimized ILC Wiggler and Vacuum Chamber • Cornell/LBNL Collaboration November 7, 2015 CesrTA Seminar 32 Wiggler Design • Basic Requirements – Large Aperture • Physical Acceptance for injected e+ beam • Improved thresholds for collective effects – Electron cloud – Resistive wall coupled bunch instability – Dynamic Aperture • Field quality • Wiggler nonlinearities • Have carried out a series of physics studies with an eye towards the engineering develop an optimized wiggler design which we hope will lead to an ILC prototype – Dynamic aperture studies using OCS2 November 7, 2015 CesrTA Seminar 33 Optimized Wiggler • Superferric ILC-Optimized CESR-c Wiggler – 12 poles (vs 14) – Period = 32 cm (vs 40) – Length = 1.68 m (vs 2.5) – By,peak = 1.95 T (vs 1.67) – Gap = 86 mm (vs 76) – Width = 238 mm – I = 141 A tdamp = 26.4 ms Misses nominal target (25 ms) x,rad = 0.56 nm·rad sd = 0.13 % November 7, 2015 CesrTA Seminar 34 Engineering Issues • Cryogenics Modifications – Indirect cooling for cold mass – Switch to cold He gas for cooling thermal shields – 42% of manpower for inner cryostat and stack assembly a significant cost reduction expected • Shorter Unit – Simplified and more robust yoke assembly – Significant cost reduction • 14 % fewer poles • 30% reduction in length • Larger aperture – Relaxed constraints on warm vacuum chamber interface with cryostat • Estimated cost savings relative to RDR value: ~25% • Wiggler Information: https://wiki.lepp.cornell.edu/ilc/bin/view/Public/CesrTA/WigglerInfo November 7, 2015 CesrTA Seminar 35 EC in Wiggler Vacuum Chamber The multipacting strips of electron cloud in the wigglers is more close to the beam 3 x 10 13 6 x 10 13 5 2.5 4 -3 (m ) 2 1.5 2 1 1 0.5 0 -10 L. Wang, ILCDR06 November 7, 2015 3 -5 0 5 X (mm) Wiggler CesrTA Seminar 10 0 -30 -20 -10 0 10 20 30 X (mm) Dipole, B=0.194T 36 Wiggler Trajectory • Note that CESR beam trajectory significant relative to stripe spacing at 2GeV • Diagnostics – Ideally should be capable of roughly millimeter transverse resolution – Longitudinal segmentation to cleanly sample stripe November 7, 2015 4mm CesrTA Seminar 37 • Expect to make several variants to explore Diagnostic Wiggler Chamber Concept Integral RFA – Electrodes – Grooves – Coatings • Modify existing extrusions Clearing Electrode Clearing Electrode 1.5mm slot spacing RFA sections 31mmx38mm sampling central fields of wiggler November 7, 2015 CesrTA Seminar 38 Survey and Alignment Rapid Tunnel Reference Surveyor (RTRS) Concept Proposal submitted for ILC DR alignment and survey studies using CesrTA wall markers internal FSI SM beam external FSI Tunnel Wall A. Reichold D. Urner LiCAS technology for automated stake-out process Reconstructed tunnel shapes (relative coordinates) collider component November 7, 2015 CesrTA Seminar 39 Electron Cloud (and Ion) Studies • Electron Cloud and Ion Studies Underway • Utilize multi-bunch turn-by-turn instrumentation – Beam profile monitors – Beam position monitor • Collaborator Participation – Sept. 2006: M. Pivi – Jan. 2007: K. Harkay (ANL), J. Flanagan (KEKB), A. Molvik (LLNL) November 7, 2015 CesrTA Seminar 40 e+ Beam Size vs Bunch Current • 2 GeV vertical bunch-by-bunch beam size for 1x45 pattern, positrons November 7, 2015 CesrTA Seminar 41 Theory and measurement of instability onset Qualitative comparison: if the transverse eigen-frequency of the electron cloud becomes comparable with the corresponding betatron frequency (xc), then the transverse motion becomes unstable. Need to take into account the horizontal motion as well. f p MHz 0.5 0.4 b 10 a m m 60 3 0.35 b 0.3 0.11 b0.4 [mm] 0.25 0.35 mA b 1/ 4 2 2 1 2 y c 0.2 0.15 0.1 0 10 20 30 40 50 See ILCDR06 Talk by L. Schachter – https://wiki.lepp.cornell.edu/ilc/pub/Public/DampingRings/CornellWorkshopTalks/Schachter.Wake-Field_in_eCloud.ppt November 7, 2015 CesrTA Seminar 42 Witness Bunch Studies – e+ Vertical Tune Shift • Initial train of 10 bunches a generate EC • Measure tune shift and beamsize for witness bunches at various spacings Positron Beam (0.75 mA/bunch, 1.9 GeV) 1.9 GeV) Positron Beam, 0.75 mA/bunch, 14 nsPositron spacing,Beam 1.9 (0.75 GeVmA/bunch, Operation 0.25 1.00 0.90 0.20 Train Witness 0.80 0.15 0.60 DQx (kHz) D Qy (kHz) 0.70 0.50 0.40 0.30 0.10 0.05 0.00 -0.05 0.20 -0.10 0.10 0.00 -0.15 -0.10 -0.20 0 100 200 300 400 500 600 Train Witness 0 100 Time (ns) Error bars represent scatter observed during a sequence of measurements November 7, 2015 200 300 400 500 600 Time (ns) 1 kHz a D0.0026 e ~ 1.5 x 1011 m-3 Ohmi, etal, APAC01, p.445 CesrTA Seminar Preliminary Results 43 Witness Bunch Studies – e- Vertical Tune Shift • Same setup as for positrons • Negative vertical tune shift and long decay consistent with EC Electron Beam, 0.75 mA/bunch, 14 ns spacing, 1.9 GeV Operation Electron Beam (0.75 mA/bunch, 1.9 GeV) Electron Beam (0.75 mA/bunch, 1.9 GeV) 0.10 0.05 -0.05 D Qx (kHz) D Qy (kHz) 0.00 -0.10 -0.15 -0.20 -0.25 Train Witness -0.30 -0.35 0 100 200 300 400 500 0.05 0.04 0.03 0.02 0.01 0.00 -0.01 -0.02 -0.03 -0.04 -0.05 600 Train Witness 0 100 Time (ns) 300 400 500 600 Time (ns) Negative vertical tune shift along train a consistent with EC Magnitude of shift along train is ~1/4th of shift for positron beam NOTE: Shift continues to grow for 1st 4 witness bunches! November 7, 2015 200 CesrTA Seminar Preliminary Results 44 Witness Bunch Studies – Comparison of e-/e+ Tunes • Magnitude of tune shift for electron beam is ~1/4th of shift observed for positron beam Positron-Electron Comparison 1.20 D Qy e+ (kHz) 0.80 0.29 0.24 0.19 0.60 0.14 0.40 0.09 0.20 D Qy e- (kHz) e+ Train e+ Witness e- Train e- Witness 1.00 0.04 0.00 -0.01 -0.20 -0.06 0 100 200 300 400 500 600 Time (ns) November 7, 2015 CesrTA Seminar 45 Fast Ion Instability? - 45 bunch train - Electrons - 14ns spacing - 1.2e10/bunch Qh 0.6 kHz full scale Instability? Linear theory predicts 100 turn growth rate for 45th bunch Vertical beam size Qv 0.5 kHz full scale Measurements underway to characterize mode spectra November 7, 2015 CesrTA Seminar 46 CesrTA Schedule • Initial Focus – Electron cloud growth and suppression in wigglers – Improvements for low emittance operations through 2009 • ILC EDR needs drive research program until early 2010 – Expect re-evaluation of program at that point – Potential for prototype testing after the EDR period • At NSF request, we have resubmitted (3 weeks ago) the CesrTA proposal jointly to DOE and NSF November 7, 2015 CesrTA Seminar 47 Now Until April 1, 2008 • Implement 4ns transverse feedback (transverse now operating) – R. Meller, M. Billing, G. Codner, J. Sikora • Install North IR Retarding Field Analyzers (RFA) for electron cloud measurements during May down • Preparatory machine studies program – Continue electron cloud and ion studies – Start exploration of low emittance operations RFA Assembly • CESR-c (existing machine layout) optics have been designed: x ~ 6.5 nm • Early work on beam-based alignment • Prepare for wiggler vacuum chamber studies – Collaboration: SLAC, LBNL – Design and construction of new vacuum chambers is a critical path item – Segmented RFA for high field operation • General infrastructure preparation – – – – Feedback Cryogenics Vacuum Other… November 7, 2015 CesrTA Seminar 48 • International Linear Collider Overview – Preparing for the Engineering Design Report (EDR) – ILC R&D at Cornell – ILC Damping Rings R&D in Detail • CesrTA Proposal – Overall Scope – Damping Rings R&D Using CESR • • • • • Concept and Goals Ring Modifications Parameters and Experimental Reach Schedule Collaborators and Projects • Synergies with Other Parts of the CLASSE Program • Conclusion and Acknowledgments November 7, 2015 CesrTA Seminar 49 Synergies • Modifications that will benefit ERL@CESR – BPM system upgrade provides electronics that will be reused for the ERL – Improvements in low emittance diagnostics – Improvements in survey and alignment capabilities – Development of machine correction methods at ultra low emittance • Potential new regimes for CHESS operations – 5 GeV low emittance lattice • 6 wiggler operation with x ~ 26 nm • Requires a ~100kW x-ray dump • Goal is 100 mA single beam operations November 7, 2015 CesrTA Seminar 50 Unique Features of R&D at CESR CESR offers: – The only operating wiggler-dominated storage ring in the world – The CESR-c damping wigglers • Technology choice for the ILC DR baseline design – Physical aperture: Acceptance for the injected positron beam – Field quality: Critical for providing sufficient dynamic aperture in the damping rings – Flexible operation with positrons and electrons – Flexible bunch spacings suitable for damping ring tests • Presently operate with 14 ns spacing • Can operate down to 4ns (or 2ns) spacings with suitable feedback system upgrades – Flexible energy range from 1.5 to 5.5 GeV • CESR-c wigglers and vacuum chamber specified for 1.5-2.5 GeV operation • An ILC DR prototype wiggler and vacuum chamber could be run at 5 GeV – Dedicated focus on damping ring R&D for significant running periods after the end of CLEO-c data-taking – A useful set of damping ring research opportunities… • The ability to operate with positrons and with the CESR-c damping wigglers offers a unique experimental reach November 7, 2015 CesrTA Seminar 51 Conclusion • CesrTA conceptual design work is ongoing – Program offers unique features for critical ILC damping ring R&D – Simulations indicate that the emittance reach is suitable for a range of damping ring beam dynamics studies – The experimental schedule will allow timely results for ILC damping ring R&D! November 7, 2015 CesrTA Seminar 52 Acknowledgments • CesrTA Studies and CESR Machine Studies – – – – – – – – – – – – – – – – J. Alexander M. Billing G. Codner J. Crittenden M. Ehrlichman (Minn) M. Forster D. Hartill R. Helms November 7, 2015 CesrTA Seminar D. Rice D. Rubin D. Sagan L. Schachter J. Shanks (REU) E. Tanke M. Tigner J. Urban 53