CesrTA Status Report

1. CesrTA Status Report Linear Collider Workshop of the Americas 2009 Mark Palmer for the CesrTA Collaboration October 1, 2009

2. Outline • CesrTA Program Overview • Updates Since TILC09 • Run #3 • Upgrade Down #4 • CTA09 Workshop • Run #4 • Experimental Program Planning • Status • CTA09 Task Lists • Implementation of Results into DR Design • Strategy for Upcoming Run • 2010 Schedule • Conclusion CesrTA Status Report - LCWA09

3. CesrTA Program • 4 Major Thrusts: • Ring Reconfiguration: Vacuum/Magnets/Controls Modifications • Low Emittance R&D Support • Instrumentation: BPM system and high resolution x-ray Beam Size Monitors • Survey and Alignment Upgrade • Electron Cloud R&D Support • Local EC Measurement Capability: RFAs, TE Wave Measurements, Shielded Pickups • Feedback System upgrade for 4ns bunch trains • Photon stop for wiggler tests over a range of energies • Local SEY measurement capability • Experimental Program • Targeting ~240 running days over course of program • Early results will feed into final stages of program Bulk of upgrades completed by mid-2009 a enables an experimental focus thru mid-2010 • Schedule coordinated with Cornell High Energy Synchrotron Source (CHESS) operations • Overall schedule somewhat “stretched” from original plan • Down time requirements (including extensions for special maintenance) • CHESS running request slightly larger than originally anticipated CesrTA Status Report - LCWA09

4. Run #3 • Run #3: May 12-June 16, 2009 • Major Activities: • Instrumentation Commissioning • BPM system • xBSM - including first single-pass measurements • 4ns Feedback (DIMTEL) • L3 EC Hardware • SLAC Chicane and EC chambers commissioned • Mitigation Studies • CesrTA 5 GeV Optics Chicane Single-Pass xBSM – Fresnel zone plate CesrTA Status Report - LCWA09

5. Upgrade Down #4 • Upgrade Down #4: June 16-July 23, 2009 • Major Activities: • xBSM upgrade - Electron line deployment • New EC vacuum chambers • Wiggler chamber with groove mitigation (CU-KEK-LBNL-SLAC) • Upgraded RFA detectors (in wiggler, Q15E/W chambers and quadrupole chamber) • Diagnostic quadrupole chamber for L3 experimental region • Amorphous Carbon chamber (CERN) in Q15W experimental section • Control Al chamber in Q15E experimental section • Grooved chamber with TiN coating in L3 Chicane (SLAC) • EC solenoid windings on ~80% of CESR drift region CesrTA Status Report - LCWA09

6. CTA09 • CTA09 (June 25-26) https://wiki.lepp.cornell.edu/ilc/bin/view/Public/DampingRings/CTA09/WebHome • Detailed evaluation of experimental program • 40 participants • Planning input for Aug-Sept 2009, Nov-Dec 2009, spring 2010 and summer 2010 runs • Organize shift from commissioning focus a experimental focus • Detailed task lists generated • See detail later this talk CesrTA Status Report - LCWA09

7. Run #4 • Run #4: August 31-September 8, 2009 • Major Activities • Electron Cloud Build-up & Mitigation • Tests of new EC-mitigating vacuum chambers • Wiggler chamber with grooves (CU-KEK-LBNL-SLAC) • Amorphous carbon coated chamber (CERN) • Grooved dipole chamber (SLAC) • Diagnostic quadrupole chamber • Upgraded RFA detectors installed and tested • Chicane Studies • Beam Size Monitors • High energy x-ray coded aperture optics (4-5 GeV) tested for x-ray beam size monitor • Commissioning of electron beam x-ray line underway • Upgraded vertical polarizer and interferometer setups for visible light beam size monitors • Bunch-by-bunch single-pass beam size measurements for EC instability studies • Ring Optics Commissioning (see summary following page) • Provide a range of conditions for EC studies (radiation distribution and stability criteria) • Characterization of IBS effects • Range of emittances for hardware characterization • Low Emittance Tuning • Digital BPM System commissioning (4ns bunch spacing) • Integration of data from new instrumentation CesrTA Status Report - LCWA09

8. CesrTA Optics All at Qh = 14.57, Qv = 9.62 • Orbit/phase/coupling correction and injection but no ramp and recovery • In all other optics there has been at least one ramp and iteration on injection tuning and phase/coupling correction CesrTA Status Report - LCWA09

9. A Few “Log Book” Snapshots Amorphous C-Coated VC (CERN) vs Al VC Amorphous Carbon Resonant Excitation of Cloud via TE Wave Carrier Signal Cyclotron Resonances Stored Beam During Wiggler Ramp xBSM Single-Bunch Measurement RFA @ center of pole central collector RFA @ center of pole, outer collector 2500 G FS 2500 G FS CesrTA Status Report - LCWA09

10. Experimental Program: Current Status • Ring Reconfiguration • Damping ring layout • 4 dedicated EC experimental regions • Upgraded vacuum/EC instrumentation • Beam Instrumentation • xBSM positron and electron lines operational • Continued optics and detector development • BPM system • ~80% of ring now has multi-bunch turn-by-turn digitizers (gen 3), 10% has single bunch t-by-t digitizers (gen 1), 10% remains on old system. • Plan to complete upgrade in November • Continued effort on data acquisition and experimental data modes • vBSM • Significant progress has been made on vertical polarization measurements which can provide a useful cross-check with the xBSM in the ultra low emittance regime • Will add new optics line for transverse and longitudinal measurements in L3 before the end of the year • Feedback system upgrade for 4ns bunch spacing is operational • Continuing to interface system more closely to the CESR control system • EC Diagnostics and Mitigation • ~30 RFAs deployed • TE wave measurement capability in each experimental region • Mitigation tests are ongoing • Low Emittance Tuning and Beam Dynamics Studies • We are within a factor of 2 of our emittance targets (presently ≤40 pm and aiming for 20pm before next September) • Continuing effort to take advantage of new instrumentation • Continuing to work towards providing low emittance conditions for beam dynamics studies Complete All systems on track to becoming fully operational CesrTA Status Report - LCWA09

11. CTA09 Task Lists • 3 Working Groups • EC Build-Up and Mitigation • Conveners: K. Harkay, Y. Suetsugu, R. Zwaska • 27 Deliverables with 21+ contributors identified • 3 Broad Catgories • EC Build-Up • Instrumentation • Mitigation • EC Simulation and Beam Dynamics • Conveners: G. Dugan, J. Flanagan • 32 Deliverables with 16 contributors identified • Divided into beam measurement and simulation categories • LET • Conveners: M. Billing, S. Guiducci, J. Shanks • 16 Deliverables with 19 contributors identified • Divided into LET and instrumentation categories • Full lists are available on CTA09 web-site (will briefly review topics here) • Participants • Priority • Target Date • Significant progress has been achieved on many of these items CesrTA Status Report - LCWA09

12. EC Build-Up Characterization of SE - Define beam measurements that provide input for SE parameters Define and carry out experiments to determine PE properties, analyze data Guidebook for understanding and using SEY and parameterizations Measurement and analysis of EC in quadrupole In-situ SEY characterization with ECLOUD1 (Al, Cu, SS, coatings) Surface conditioning - Beam studies and analysis of surface conditioning (SS, Cu, Al, coatings) (time evolution) EC lifetime measurement with witness bunches; find SEY @ E=0; time evolution Multipacting threshold bunch current (PE vs SE dominated) (vs. vacuum pressure rise?) Carry out machine studies to compare component surfaces (SS, copper, Al, etc.) Instrumentation Modeling of RFA as part of the EC system (resonance due to SE from grid) Estimation of electron density from RFA data Correlate RFA with TE wave measurement in drifts and bends TE wave vs. resonant BPM; time resolved Devise a plan for correlating RFA with TE wave measurements in a wiggler; time structure (EC at BY=0 has longer lifetime) Investigate shielded electrode for wiggler measurements or other Mitigation Determine best techniques for general mitigation strategy Mitigation in wiggler: Cu Groove (TiN coated) Mitigation in wiggler: Clearing electrode Mitigation in straight: Enamel electrode Long term reliability of electrodes and coatings Amorphous carbon NEG coating Mitigation in wiggler: Enamel electrode Solenoid field Beam pipe with photon absorption (roughness), PE trapping Beam pipe with antechamber CTA09 Task List – EC Build-Up and Mitigation CesrTA Status Report - LCWA09

13. EC Simulations Estimate of the scattered radiation around the CESR ring. This will need X-ray scattering and absorption data for guidance Include the details of the RFA structure itself into the cloud simulation programs. Run simulations for the existing RFA drift and dipole data sets for a range of cloud physics parameters, to establish the best fit ranges of these parameters for different surfaces and mitigation techniques. Correlate with in-situ SEY measurements and parameters found from ringwide coherent tune shift fits. Run simulations for the existing RFA wiggler data sets for a range of cloud physics parameters, to establish the best fit ranges of these parameters for different surfaces and mitigation techniques in the wigglers. Identify experimentally accessible signatures of the structure of the cloud in the By=0 wiggler regions. Run simulations for the existing data sets for a range of cloud physics parameters describing the ringwide drifts and dipoles, to establish the best fit ranges of these parameters. Develop a procedure for automating the (2D) simulation of a given RFA data set. Automate the calculation of tune shifts from drifts and dipoles performed with and without coherent motion of the whole train. Develop an improved photoelectron model (quantum efficiency, photoelectron energy, angular spectra, effect of fluorescence) based on existing data, with measurements if needed Using simulations, define set of experiments (RFA, TE wave, tune shift) which can be done at CesrTA that can independently determine the key electron cloud physics paramters. Simulate cloud densities sampled by TE wave measurements Compute effect of nonuniform cloud distrbution on TE wave phase shifts in the presence of magnetic field "Estimate the threshold, growth time and mode spectrum for multibunch instabilities at CesrTA. Consider witness bunch configurations as well as train measurements. " Estimate the threshold for the head-tail instability at CesrTA. Consider witness bunch configurations as well as train measurements. Estimate the expected level of incoherent emittance growth at CesrTA for positrons and electrons. Consider witness bunch configurations as well as train measurements to control better the cloud density. Develop capability to simulate cloud and RFA in quadrupole Run simulations for the RFA quadrupole data sets for a range of cloud physics parameters, to establish the best fit ranges of these parameters for different surfaces and mitigation techniques. Resolve discrepancies between simulation codes regarding the structure of the cloud in the By=0 regions Estimate contributions to tune shifts from wigglers and quadrupoles. Develop estimates of cloud-induced betatron phase advances over sections of the ring. Beam Studies Complete reprocessing of older tune shift data from Nov 08 and Jan 09 runs. Develop techniques and software to process tune shift data from Dimtel feedback system Process Dimtel data from June 09 run. Develop software to process tune shift data and multibunch mode spectra from new BPM system. Make witness bunch and train current dependence measurements with 4, 8, 12, 16 ns using Dimtel system. Make measurements with pinger on, all bunches damped except one. Make witness bunch and train current dependence measurements, with 4, 8, 12, 16 ns using the new BPM system, with existing (full train) pingers. Cross check with Dimtel system measurements. Use X-ray beam size monitor to measure growth of vertical emittance vs. bunch number in trains of positrons and electrons at 2 and 5 GeV, at various bunch spacings and currents. (Check that there is no coherent signal.) Repeat this at different working points. Develop method to use Dimtel system to damp all bunches but one, excite this bunch with shaker and measure tune. Automate. Make witness bunch and train current dependence measurements, using the new BPM system to make betatron phase advance meaurements as a function of bunch number. Use new BPM system to observe threshold and modes of coherent multi-bunch instabilities at 4, 8, 12, 16 ns as a function of cloud configuration and feedback settings Establish appropriate cloud conditions for head-tail instability and measure threshold (via synchro-betatron sideband enhancement using BPM system and feedback system) and measure centroid and size variations with XBSM monitor. Vary chromaticity , beam current, working point. Scan working point and measure distance in tune space from center of tune distribution to resonance lines? Use incoherent Schottky spectrum? (F. Caspers) CTA09 Task List – EC Simulation & Beam Studies CesrTA Status Report - LCWA09

14. Instrumentation Complete CESR BPM upgrade BPM tilts – disentangle using either C11 & C22 vs C12 via phase measurement, MIA and/or ORM Measure BPM Alignments Phase and/or Trajectory measurements for different bunches within the trains (Model Independent Analysis?) xBSMs: Coded Aperture and Zone Plate measurements for intercalibration using vertical bumps, or coupling variation to change beam size vBSMs: Vertical polarization and interferometric measurements for calibration using vertical bumps, or coupling variation to change beam size Horizontal BSM: study of different options: slow horizontal scan of vertical monitors, the depth of field issue, or possibly using set of vertical bends (V dispersion issue) or interferometer Horizontal pulsed scraper measurements 4 ns Feedback -Establish convenient methods for changing conditions and reading out bunch-by-bunch tunes under various conditions LET Precision vertical dispersion & coupling measurements Low emittance tuning controls: Coupling.- both global and local Low emittance tuning controls: Vertical Dispersion - both global and local Low emittance tuning controls: Horizontal Dispersion - both global and local Quasi-uniform sextupole distributions Skew sextupole tuning controls – global Touschek lifetime measurements vs beam energy CTA09 Critical Tasks - LET CesrTA Status Report - LCWA09

15. DR Design Work • A major component of the CesrTA program is incorporation of our results into the DR technical design • We have already gathered a great deal of data on the EC growth in the wiggler region and elsewhere • A number of mitigation comparisons are now available • Integrate simulation inputs based on CesrTA measurements into ILC DR projections • Milestones • Preliminary evaluation of mitigation choices in early 2010 • Major update for ILC-CLIC meeting in September 2010 CesrTA Status Report - LCWA09

16. Run #5 Planning • CesrTA Run #5: November 17th – December 23rd • There will be a short down preceding the run • Install new diagnostic chambers • Q15 TiN on Al chamber for tests in CESR Arcs • Quadrupole chamber with mitigation • Install supporting hardware • Additional TE Wave pickups to allow horizontal and vertical polarization measurements in L3. Also, dedicate pickups in chicane for local (resonance) measurements • Through the end of November we will focus on establishing machine conditions and continuing to commission new instrumentation • Our goal is to enable a focused experimental period for all of December • Particular focus on low emittance tuning and beam dynamics studies • We hope that many of you will join us during this period CesrTA Status Report - LCWA09

17. 2010 Schedule • 2 large machine downs – March and July-August • Run #6 in early spring 2010 • We are finalizing the exact dates but will likely start in mid-April (tentatively the 13th) • Run #7 • Final run in present program • Tentatively planned for September 2010 • Some risk given that it’s at the extreme end of our funding cycle • But… • We are submitting a proposal to the NSF for continued accelerator R&D funding to 2013 • NSF Site-Visit to Cornell scheduled for December 2-3, 2009 • 2 major mitigation tests which are part of the original scope are planned for 2010 • Wiggler with clearing electrode • NEG test in L3 experimental region • These runs will give us the best opportunity to operate at ultra low emittance and study emittance dilution issues • We will also direct significant effort towards incorporating our EC results into the ILC DR Technical Design CesrTA Status Report - LCWA09

18. Conclusion • CesrTA Program Today and Tomorrow • Today: • Contributions from several labs • TE Wave Experiments from Stefano De Santis • Simulation and Beam Dynamics update from Gerry Dugan • Mitigation update from Joe Calvey • Discussion of EC planning for CesrTA later this afternoon in conjunction with overall EC planning for ILC DR • Tomorrow: • LET/Instrumentation update from Mike Billing • xBSM update from Dan Peterson CesrTA Status Report - LCWA09