CESR as a Vehicle for ILC Damping Rings R&D
Mark Palmer
Cornell Laboratory for
Accelerator-Based Sciences and Education
April 24, 2007 LBNL Center for Beam Physics Seminar 2
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
April 24, 2007 LBNL Center for Beam Physics Seminar 3
The ILC
• Basic Numbers– 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
• 16K Cavities• 2K Cryostats
• Machine Configuration– 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
April 24, 2007 LBNL Center for Beam Physics Seminar 4
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
April 24, 2007 LBNL Center for Beam Physics Seminar 5
ILC R&D at Cornell
• R&D Efforts– Helical Undulator Polarized
Positron Source
– Ring-to-Main Linac
– Low Emittance Transport (RTML and Main Linac)
– Damping Rings
– SRF
– Detector (TPC)
• Also management contributions
April 24, 2007 LBNL Center for Beam Physics Seminar 6
ILC Damping Rings R&D Overview
J. Urban
• Damping Rings– Simulation– Electron Cloud and Ion Effects– Technical Systems (wigglers, kickers, instrumentation…)– CesrTA Development– BCD and RDR Support
• 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)
April 24, 2007 LBNL Center for Beam Physics Seminar 7
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
April 24, 2007 LBNL Center for Beam Physics Seminar 8
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
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
OCS v6TME Lattice
Circled items play a key role in our local R&D plans…
250 km main linac bunch trainis “folded” into the DRs
April 24, 2007 LBNL Center for Beam Physics Seminar 9
RDR Version of ILC DR Layout
e- ring circulates in opposite direction in same central tunnel
April 24, 2007 LBNL Center for Beam Physics Seminar 10
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
April 24, 2007 LBNL Center for Beam Physics Seminar 11
Moving to a Single Positron DR
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.
M. PiviILCDR06
No additionalsuppression techniques assumed in dipoles andwigglers!
April 24, 2007 LBNL Center for Beam Physics Seminar 12
Suppressing Electron Cloud in Wigglers
0 20 40 60 80 100 12010
9
1010
1011
1012
1013
1014
Bunch ID
e (
m-3
)
average density, long traincentral density, long trainaverage density, bunch train, -100Vcentral density, bunch train, -100Vaverage density, bunch train, 200Vcentral density, bunch train, 200V
stripline position
Strip-line typeWire type
Strip-line type Wire type
Calculation of the impedance ( Cho, Lanfa)
Design & test of impedance is under the way, test in PEPII Dipole & CESR Wiggler
Submitted to PRSTAB
Suetsugu’s talk
L. WangILCDR06
April 24, 2007 LBNL Center for Beam Physics Seminar 13
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
April 24, 2007 LBNL Center for Beam Physics Seminar 14
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
April 24, 2007 LBNL Center for Beam Physics Seminar 15
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
April 24, 2007 LBNL Center for Beam Physics Seminar 16
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:
• 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
32
2
15
8
wp
x
xqx kJ
C
April 24, 2007 LBNL Center for Beam Physics Seminar 17
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
April 24, 2007 LBNL Center for Beam Physics Seminar 18
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
April 24, 2007 LBNL Center for Beam Physics Seminar 19
Instrumentation for Ultra-Low Emittance Measurement
• Typical Beam Sizes– Vertical: y~10-12 m
– Horizontal: x ~ 80 m (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
April 24, 2007 LBNL Center for Beam Physics Seminar 20
GaAs Detector for X-ray Imaging
Sig
nal
(A
DC
Cou
nts
)
Position (m)Fast enough for single bunch resolution
First bunch-by-bunch beam size data in CHESS conditions Significant CHESS support
= 142 +/- 7 mDifferent symbolsrepresent differentbunches
Pinhole camerasetup at B1 hutch
NEW: GaAs arrays from Hamamatsu• 1x512 linear array• 25 m pitch• 1st sample has recently arrived
April 24, 2007 LBNL Center for Beam Physics Seminar 21
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
p q
25um Be
detectorzone plate
Multilayer W/C mirrors;
April 24, 2007 LBNL Center for Beam Physics Seminar 22
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
April 24, 2007 LBNL Center for Beam Physics Seminar 23
Experimental Reach
Parameter Value
E 2.0 GeV
Nwiggler 12
Bmax 2.1 T
x 2.25 nm
Qx 14.59
Qy 9.63
Qz 0.075
E/E 8.6 x 10-4
x,y 47 ms
z (with VRF=8.5MV) 9 mm
c 6.4 x 10-3
Touschek(Nb=2x1010) >10 minutes
Baseline Lattice
April 24, 2007 LBNL Center for Beam Physics Seminar 24
Tune scans• Tune scans used to identify suitable working points
Qx~14.59 Qy~9.63
April 24, 2007 LBNL Center for Beam Physics Seminar 25
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
April 24, 2007 LBNL Center for Beam Physics Seminar 26
Lattice Evaluation
Misalignment Nominal Value
Quadrupole, Bend and Wiggler Offsets
150 m
Sextupole Offsets 300 m
Quadrupole, Bend, Wiggler and Sextupole Rotations
100 rad
• 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
April 24, 2007 LBNL Center for Beam Physics Seminar 27
Vertical Emittance Sensitivities(Selected Examples)
April 24, 2007 LBNL Center for Beam Physics Seminar 28
Low Emittance Operations
• Have evaluated our ability to correct for ring errors with the above lattice– 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
Nominal Values
April 24, 2007 LBNL Center for Beam Physics Seminar 29
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
April 24, 2007 LBNL Center for Beam Physics Seminar 30
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, …
April 24, 2007 LBNL Center for Beam Physics Seminar 31
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
April 24, 2007 LBNL Center for Beam Physics Seminar 32
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
April 24, 2007 LBNL Center for Beam Physics Seminar 33
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
April 24, 2007 LBNL Center for Beam Physics Seminar 34
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 damp = 26.4 ms
x,rad = 0.56 nm·rad
= 0.13 %
Misses nominal target (25 ms)
April 24, 2007 LBNL Center for Beam Physics Seminar 35
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 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
April 24, 2007 LBNL Center for Beam Physics Seminar 36
EC in Wiggler Vacuum Chamber
-30 -20 -10 0 10 20 300
1
2
3
4
5
6x 10
13
X (mm)
(m-3
)-10 -5 0 5 100
0.5
1
1.5
2
2.5
3x 10
13
X (mm)
Wiggler Dipole, B=0.194T
The multipacting strips of electron cloud in the wigglers is more close to the beam
L. Wang, ILCDR06
April 24, 2007 LBNL Center for Beam Physics Seminar 37
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 4mm
April 24, 2007 LBNL Center for Beam Physics Seminar 38
Diagnostic Wiggler Chamber Concept
• Expect to make several variants to explore– Electrodes– Grooves– Coatings
• Modify existing extrusions
RFA sections 31mmx38mm sampling central fields of wiggler
Clearing Electrode
1.5mm slot spacing
Clearing Electrode
Integral RFA
April 24, 2007 LBNL Center for Beam Physics Seminar 39
Survey and Alignment
collider component
Rapid Tunnel Reference Surveyor (RTRS) ConceptProposal submitted for ILC DR alignment and survey studies using CesrTA
Tunnel Wall
Reconstructed tunnel shapes(relative co-ordinates)
wall markers internal FSI external FSISM beam
LiCAS technologyfor automated stake-out process
A. Reichold
D. Urner
April 24, 2007 LBNL Center for Beam Physics Seminar 40
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)
April 24, 2007 LBNL Center for Beam Physics Seminar 41
e+ Beam Size vs Bunch Current
• 2 GeV vertical bunch-by-bunch beam size for 1x45 pattern, positrons
April 24, 2007 LBNL Center for Beam Physics Seminar 42
Theory and measurement of instability onset
0.35 mA
0 10 20 30 40 500.1
0.15
0.2
0.25
0.3
0.35
0.4
b
103
0.11
0.4
[ ]b mm
0.5
60
pf MHz
a m
1/2 4
221 y
bb
c
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.
See ILCDR06 Talk by L. Schachter – https://wiki.lepp.cornell.edu/ilc/pub/Public/DampingRings/CornellWorkshopTalks/Schachter.Wake-Field_in_eCloud.ppt
April 24, 2007 LBNL Center for Beam Physics Seminar 43
Witness Bunch Studies –e+ Vertical Tune Shift
• Initial train of 10 bunches generate EC• Measure tune shift and beamsize for witness bunches at various spacings
1 kHz e ~ 1.5 x 1011 m-3
Ohmi, etal, APAC01, p.445
Positron Beam, 0.75 mA/bunch, 14 ns spacing, 1.9 GeV Operation
Preliminary ResultsError bars represent scatter observed during a sequenceof measurements
April 24, 2007 LBNL Center for Beam Physics Seminar 44
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
Preliminary ResultsNegative vertical tune shift along train consistent with ECMagnitude of shift along train is ~1/4th of shift for positron beamNOTE: Shift continues to grow for 1st 4 witness bunches!
April 24, 2007 LBNL Center for Beam Physics Seminar 45
Witness Bunch Studies –Comparison of e-/e+ Tunes
• Magnitude of tune shift for electron beam is ~1/4th of shift observed for positron beam
April 24, 2007 LBNL Center for Beam Physics Seminar 46
Fast Ion Instability?
- 45 bunch train- Electrons- 14ns spacing- 1.2e10/bunch
Qh
0.6 kHz full scale
Instability?Linear theory predicts100 turn growth rate for45th bunch
Qv
0.5 kHz full scale
Vertical beam size
Measurements underway to characterize mode spectra
April 24, 2007 LBNL Center for Beam Physics Seminar 47
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
April 24, 2007 LBNL Center for Beam Physics Seminar 48
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
• 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…
RFA Assembly
April 24, 2007 LBNL Center for Beam Physics Seminar 49
• 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
April 24, 2007 LBNL Center for Beam Physics Seminar 50
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
April 24, 2007 LBNL Center for Beam Physics Seminar 51
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
April 24, 2007 LBNL Center for Beam Physics Seminar 52
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!
April 24, 2007 LBNL Center for Beam Physics Seminar 53
Acknowledgments
• CesrTA Studies and CESR Machine Studies– J. Alexander
– M. Billing
– G. Codner
– J. Crittenden
– M. Ehrlichman (Minn)
– M. Forster
– D. Hartill
– R. Helms
– D. Rice
– D. Rubin
– D. Sagan
– L. Schachter
– J. Shanks (REU)
– E. Tanke
– M. Tigner
– J. Urban