Compare options: Compare options: simulations recent historysimulations recent history

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.

Need for mitigation

Outstanding Questions about key remedies:

1) Are thin film coatings effective to stably decrease SEY < 1.2 ? Is “conditioning” effective to stably decrease SEY < 1.2 ?

2) Fins: are fin-chambers viable to suppressing electron cloud in magnets ?

(resolve simulation discrepancy)

3) Clearing electrodes: is RF power load tolerable ? are impedance and HOM tolerable ?

ILC DAMPING RING R&D OBJECTIVES2.2.3 Electron Cloud

2.2.3.1 Characterize electron-cloud build-upRequired for Baseline Priority: 22.2.3.2 Develop electron-cloud suppression techniquesRequired for Baseline Priority: 12.2.3.3 Develop modeling tools for e-cloud instabilitiesRequired for Baseline Priority: 1 2.2.3.4 Determine electron-cloud instability thresholdsRequired for Baseline Priority: 1

2.2.4 Ion Effects

2.2.4.1 Characterize ion effectsRequired for Baseline Priority: 1 2.2.4.2 Specify techniques for suppressing ion effectsRequired for Baseline Priority: 1

COLLECTIVE INSTABILITIES

4

Electron cloud issues: Milestones

1. Test clearing electrodes(a) characterize impedance, HOM, power load(b) machine studies

2. Test groove concepts(a) characterize impedance, HOM, power load(b) machine studies

3. Test coating techniques(a) Secondary electron yield measurements(b) machine studies

4. Investigate alternative remedies solutions5. Characterize the electron cloud build up6. Characterize the electron cloud instability7. Integrated modeling: cloud, impedance, space charge..

R&D MILENSTONES

TOWARDS A

TECHNICAL DESIGN REPORT TDR (2008)

6

Electron cloud issues: Milestones

1. Test clearing electrodes(a) characterize impedance, HOM, power load

analytical estimatessimulate MAFIA, A. Krasnyhk, Cho Ngsimulate with VORPAL, V. Ivanov (?)simulate, F. Caspers

(b) machine studiestest in HCX in a quadrupole or drift region, A. Molviktest in ESA preliminary to PEPII installation, M. Pivi, test in PEPII in bend chicane, M. Pivi

test in CESR in wiggler section, M. Palmertest in KEKB arc section bend or wiggler section, Y. Suetsugutest in LHC arc section bend section, F. Caspers

(c) develop diagnostic electron cloud diagnostic for test chambers, A. Molvik electron cloud diagnostic for test chambers, R. Macek

7

Electron cloud issues: Milestones

2. Test groove concepts(a) characterize impedance, HOMK. Bane numerical estimation, G. Stupakov analytical

(b) machine studiesrectangular grooves drift SLAC, M. Pivitriangular grooves in bend section SLAC, M.Pivitriangular grooves in wiggler section CESR, M. Palmer

(c) develop diagnostic electron cloud diagnostic for test chambers, A. Molvik electron cloud diagnostic for test chambers, R. Macek

8

Electron cloud issues: Milestones

3. Test coating techniques and determine conditioning effectiveness

(a) Secondary electron yield measurements

measuring SEY, Y. Suetsugu

measuring SEY, R. Kirby

measuring SEY, (N. Hilleret)

(b) machine studies

installation of test chambers in KEKB Cu, TiN, NEG, Y. Suetsugu

SEY conditioning test in PEP-II, M. Pivi

Installation of chambers in CESR, M. Palmer

(c) manufacturing and diagnostics

building chambers for installations, S. Marks

9

Electron cloud issues: Investigators

4. Characterize the electron cloud build upwiggler 3D simulations CLOUDLAND, L. Wangwiggler 3D simulations WARP/POSINST, C. Celatacharacterize ecloud in quadrupole, M. Pivicharacterize ecloud in quadrupole, C. Celatafill pattern as possible mitigation, M. Venturinicompile e-cloud density over the machine, M. Pivioptimize clearing electrode design, (Cornell)optimize clearing electrode design, L. Wangoptimize clearing grooves design, W. Braunsoptimize clearing grooves design, L. Wangoptimize clearing grooves design, M. Venturini

10

Electron cloud issues: Milestones

5. Characterize the electron cloud instabilityCharacterize single-bunch instability PEHTS, K. OhmiCharacterize single-bunch instability HEAD-TAIL, F. ZimmermannCharacterize single-bunch instability quasi-static QUICKPIC, P. SpentzourisCharacterize single-bunch instability in wiggler 3D WARP, C. CelataCharacterize single-bunch instability in lattice CMAD, M. Pivi

11

Electron cloud issues: Milestones

6. Integrated modelingCharacterize instability FRAMEWORK, P. Spentzouris

12

Electron cloud issues: Timescale

1. Test clearing electrodes1. In PEP-II by 20072. In CESR by 2008

2. Test groove concepts1. In PEP-II by 20072. In CESR by 2008

3. Test coating techniques1. In KEKB, by 20072. In PEPII, by 20073. In CESR, by 2008

4. Characterize the electron cloud build upCompile list of electron cloud density in ring by 2007

5. Characterize the electron cloud instabilityby TDR

6. Integrated modelingby TDR

2.2.3.A Model electron cloud instabilityStatus as at 10/08/2006: ProposedUse WARP/POSINST to compare 2D and 3D electron cloud instability code validity,with focus on the wiggler region. Begin studies of fast head-tail instability threshold.Required for BaselineAddresses Objectives:Investigators:Description:Characterize electron-cloud build-up 2.2.3.1Develop modeling tools for electron-cloud instabilities 2.2.3.3John Byrd, LBNLChristine Celata, LBNL *Gregg Penn, LBNLMarco Venturini, LBNL

MILENSTONES

“Milestones” DateMilenstone 1 XX 200XMilenstone 2 XX 200XMilenstone 3 XX 200X

2.2.3.B Model electron-cloud build-up and instabilities

Status as at 10/08/2006: In progressDevelop a self-consistent simulation code for generating electron cloud and studying theinstability. Benchmark the results of the simulation against control experiments in apositron ring. Required for BaselineAddresses Objectives:Investigators:Description:Develop modeling tools for electron-cloud instabilities 2.2.3.3Determine electron-cloud instability thresholds 2.2.3.4Mauro Pivi, SLAC *Lanfa Wang, SLAC, Eun-Kin San + 1 student

1st EXAMPLE

“Milestones” Date InvestigatorsSelf-consistent simulation code: run for ILC and LHC Mar 2007 MP, ESSelf-consistent simulation code: benchmarking with other single-bunch codes (WARP/D-TAIL/PEHTS,ORBIT) Apr 2007 MP, LWSelf-consistent code: Complete set of simulations for ILC DR Sep 2007 MPSelf-consistent code: benchmarking with LHC measurements Nov 2007 ES

2.2.3.C Model electron-cloud build-up and instabilities

Status as at 28/04/2006: ProposedAssess thresholds of instability in more realistic simulations applied to various dampingring configurations.Required for BaselineAddresses Objectives:Investigators:Description:Characterize electron-cloud build-up 2.2.3.1Develop modeling tools for electron-cloud instabilities 2.2.3.3Determine electron-cloud instability thresholds 2.2.3.4Aleksandar Markovik, RostockGisela Poplau, RostockUrsula van Rienen, RostockRainer Wanzenberg, DESY *

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.3.D Model electron-cloud build-up and instabilities

Status as at 28/04/2006: ProposedModel electron-cloud build-up and instabilities.Required for BaselineAddresses Objectives:Investigators:Description:Characterize electron-cloud build-up 2.2.3.1Develop modeling tools for electron-cloud instabilities 2.2.3.3Determine electron-cloud instability thresholds 2.2.3.4Jim Crittenden, Cornell *

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.3.E Model electron cloud build-up and instabilities

Status as at 28/04/2006: In progressModel electron cloud build-up and instabilities.Required for BaselineAddresses Objectives:Investigators:Description:Develop modeling tools for electron-cloud instabilities 2.2.3.3Kazuhito Ohmi, KEK *

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.3.F Electron cloud lab measurements and PEP-II studies

Status as at 10/08/2006: In progressTo demonstrate the reduction and stabilization of the surface secondary electron yieldbelow the threshold for the onset of the electron cloud in the damping ring. Ongoingprojects for installation of dedicated chambers in the PEP-II LER beamline include:chambers with rectangular grooves; and secondary electron yield (SEY) tests, includingtests of the combined electron and photon conditioning in an accelerator environment,electron flux, beam spectra along trains and growth times.Required for BaselineDescription:Develop electron-cloud suppression techniques 2.2.3.2Experimental studies at PEP-II 4.1.1.6Gerard Collet, SLAC,Bob Kirby, SLAC, Nadine Kurita, SLAC, Bob Macek, LANL,Mauro Pivi, SLAC *,Tor Raubenheimer, SLAC, John Seeman, B. McKee, Don Arnett SLAC, Cristina Vaccarezza, INFN-LNF, Lanfa Wang, SLAC, Andy Wolski, Liverpool/CI

2nd EXAMPLE

Milestones Date InvestigatorsProject 1. Fabrication of the prototype rectangular chambers Done

Installation in PEP-II LER Nov 2006 MP,NK,GC, BM, JS, DA

Results of measurements May 2007 MP, RK

Project 2. Fabrication of SEY test chamber DoneInstallation in PEP-II LER Nov 2006 MP, BM, GCResults of measurements May 2007 MP,

RK

2.2.3.G Studies of clearing electrodes for suppressingelectron cloud build-up

Status as at 10/08/2006: ProposedPerform feasibility studies for the use of clearing electrodes for suppressing the build-upof electron cloud. Design of vacuum chambers with clearing electrodes. Calculation ofimpedance.Required for BaselineAddresses Objectives:Investigators:Description:Develop electron-cloud suppression techniques 2.2.3.2Karl Bane, SLAC, Stefano de Santis, LBNLBrett Kuekan, SLAC, Alexander Novokhatski, SLACMauro Pivi, SLAC *, Pantaleo Raimondi, INFN-LNF,Lanfa Wang, SLAC

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.3.H Electron cloud studies in DAFNE

Status as at 10/08/2006: ProposedInstallation of a TiN coated chamber in the DAFNE positron ring. Installation of threeelectron detectors in DAFNE: one in the electron ring; one in a TiN coated section ofthe positron ring; one in an uncoated section of the positron ring. Compare the electroncloud density measured in DAFNE with the predictions of various codes. Studyelectron cloud in wigglers.Required for BaselineAddresses Objectives:Investigators:Description:Characterize electron-cloud build-up 2.2.3.1Develop modeling tools for electron-cloud instabilities 2.2.3.3Experimental studies at DAFNE 4.1.1.4Roberto Cimino, INFN-LNF, Alberto Clozza, INFN-LNF *Cristina Vaccarezza, INFN-LNF

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.3.I CESR-TF wiggler and electron cloud studies

Status as at 10/08/2006: ProposedStudy wiggler vacuum performance and electron cloud effects.Required for BaselineAddresses Objectives:Investigators:Description:Characterize electron-cloud build-up 2.2.3.1Develop modeling tools for electron-cloud instabilities 2.2.3.3Specify vacuum chamber material and geometry 3.1.1.1Develop engineering design of principal vacuum chamber components 3.1.1.2John Byrd, LBNL *Stefano de Santis, LBNLMauro Pivi, SLACMarco Venturini, LBNLLanfa Wang, SLACMichael Zisman, LBNLMilestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.3.K Studies of grooved vacuum chamber surfaces for electron cloud suppression

Status as at 18/08/2006: In progressDetermine the optimum size and shape (including rectangular and triangular) grooves inthe vacuum chamber surface for suppressing the development of electron cloud indifferent regions (e.g. field-free region, dipole, and wiggler). Demonstrate suppressioncapabilities of grooved chamber surfaces. Understand the technical and physicalimplications of grooved chamber surfaces.Required for BaselineAddresses Objectives:Investigators:Description:Develop electron-cloud suppression techniques 2.2.3.2Bob Kirby, SLACMauro Pivi, SLAC *Tor Raubenheimer, SLACLanfa Wang, SLACMilestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.3.L Experiments on suppression of electron cloud effect

Status as at 19/09/2006: ProposedDevelopment of a beam duct with ante-chambers. Survey of surfaces with a lowsecondary electron yield, and development of a clearing electrode. Measurement ofelectron density in a vacuum pipe.Required for BaselineAddresses Objectives:Investigators:Description:Develop electron-cloud suppression techniques 2.2.3.2Hitoshi Fukuma, KEKKen-ichi Kanazawa, KEKKyo Shibata, KEKYusuke Suetsugu, KEK *

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.3.M Measurement of electron cloud instabilities

Status as at 19/09/2006: ProposedMeasurement of beam spectrum, beam size and so on.Required for BaselineAddresses Objectives:Investigators:Description:Characterize electron-cloud build-up 2.2.3.1Develop modeling tools for electron-cloud instabilities 2.2.3.3Determine electron-cloud instability thresholds 2.2.3.4John Flanagan, KEK *Kazuhito Ohmi, KEK

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.3.N Benchmarking of electron-cloud build-up simulations

Status as at 20/09/2006: In progressPerform electron-cloud build-up simulations for the DAFNE wiggler and performqualitative comparison with measurements (pressure rise, beam instability, possiblydesignated electron detectors). (Run simulations at CERN using field maps from LNF.)Study efficiency of various proposed electron-cloud countermeasures in simulations.Required for BaselineInvestigators:Description:Characterize electron-cloud build-up 2.2.3.1Develop electron-cloud suppression techniques 2.2.3.2Roberto Cimino, INFN-LNFOleg Malyshev, ASTeCRon Reid, ASTeCCristina Vaccarezza, INFN-LNFRainer Wanzenberg, DESYFrank Zimmermann, CERN *Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.3.O Improvement of electron-cloud simulation codes

Status as at 20/09/2006: In progressImplement an antechamber geometry and, if foreseen by ILC design, also synchrotronradiation stops and/or clearing electrodes in ECLOUD code. Update ECLOUD modelparameters based on the results of code benchmarking.Required for BaselineAddresses Objectives:Investigators:Description:Characterize electron-cloud build-up 2.2.3.1Roberto Cimino, INFN-LNFOleg Malyshev, ASTeCRon Reid, ASTeCCristina Vaccarezza, INFN-LNFRainer Wanzenberg, DESYFrank Zimmermann, CERN *

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.3.P Predict electron-cloud effect in the damping rings

Status as at 20/09/2006: In progressSimulate instability thresholds with HEADTAIL for a 3 km, 6 km and 17 km dampingring and compare them with predicted electron densities. Estimate the importance ofincoherent emittance growth due to electron cloud for the different damping ringdesigns. Repeat electron-cloud build-up and instability simulations using updatedchamber material properties and vacuum chamber layout.Required for BaselineAddresses Objectives:Description:Determine electron-cloud instability thresholds 2.2.3.4Roberto Cimino, INFN-LNFOleg Malyshev, ASTeCRon Reid, ASTeCCristina Vaccarezza, INFN-LNFRainer Wanzenberg, DESYFrank Zimmermann, CERN *

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.3.Q Experimental determination of surface parameters for electron-cloud buildup

Status as at 20/09/2006: In progressStudy the dependence on electron and photon doses of the experimentally determinedvalues of SEY and their relevance for simulations of electron-cloud build-up. CompareDAFNE Al surface properties with other possible materials.Required for BaselineAddresses Objectives:Investigators:Description:Characterize electron-cloud build-up 2.2.3.1Roberto Cimino, INFN-LNFOleg Malyshev, ASTeCRon Reid, ASTeCCristina Vaccarezza, INFN-LNFRainer Wanzenberg, DESYFrank Zimmermann, CERN *

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.3.R Develop a PIC code for computing electron cloud and ion effects

Status as at 20/09/2006: In progressDevelop FAKTOR2, a PIC code for computing multiple effects of nonrelativisticcharges.Required for BaselineAddresses Objectives:Investigators:Description:Develop modeling tools for electron-cloud instabilities 2.2.3.3Characterize ion effects 2.2.4.1Warner Bruns, CERN *Daniel Schulte, CERNFrank Zimmermann, CERN

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.4.A Experimental studies of fast ion instability at the LBNL-ALS

Status as at 10/08/2006: In progressMeasure fast beam-ion instability growth rate as a function of emittance. Study effectsof mini-gaps in bunch train.Required for BaselineAddresses Objectives:Investigators:Description:Characterize ion effects 2.2.4.1John Byrd, LBNL *Stefano de Santis, LBNLMarco Venturini, LBNLMichael Zisman, LBNL

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.4.B Numerical and analytical studies of two-stream (beam- ion) instabilities

Status as at 10/08/2006: In progressPerform numerical and analytical studies of two-stream (beam-ion) instabilities,including: realistic model of gas species; realistic lattice model; effects of radiationdamping; effects of fast feedback systems; resistive-wall wake fields. The aim is tospecify the vacuum pressure necessary to avoid instability, and to understand effectssuch as the nonlinearities in the lattice. The simulation studies will be benchmarkedwith the analytical approach.Required for BaselineAddresses Objectives:Investigators:Description:Characterize ion effects 2.2.4.1Specify techniques for suppressing ion effects 2.2.4.2Lanfa Wang, SLAC *

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.4.C Studies of fast ion instability

Status as at 28/04/2006: In progressCharacterize ion effects in the damping rings.Required for BaselineAddresses Objectives:Investigators:Description:Characterize ion effects 2.2.4.1Eun-San Kim, KNUKazuhito Ohmi, KEK *

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.4.D Studies of fast ion instability

Status as at 11/08/2006: In progressPerform analytical study of the fast ion instability.Required for BaselineAddresses Objectives:Investigators:Description:Characterize ion effects 2.2.4.1Eckhard Elsen, DESYGuoxing Xia, DESY *

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.4.E Studies of fast ion instability

Status as at 28/04/2006: ProposedCharacterize ion effects in the damping rings.Required for BaselineAddresses Objectives:Investigators:Description:Characterize ion effects 2.2.4.1Specify techniques for suppressing ion effects 2.2.4.2Jim Crittenden, Cornell *

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.4.F Studies of suppression techniques for fast ion instability

Status as at 10/08/2006: ProposedStudy techniques for suppressing the fast ion instability, and specify an appropriateremedy for the damping rings. Techniques to be studied include: variation of bunchtrain pattern; clearing electrodes; beam shaking; fast feedback systems.Required for BaselineAddresses Objectives:Investigators:Description:Specify techniques for suppressing ion effects 2.2.4.2Lanfa Wang, SLAC *

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.4.G Experimental studies of fast ion instability

Status as at 10/08/2006: ProposedExperimental studies of fast ion instability, if opportunities arise.Required for BaselineAddresses Objectives:Investigators:Description:Characterize ion effects 2.2.4.1Lanfa Wang, SLAC *

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.4.H Measure fast ion instability in KEK-ATF

Status as at 11/08/2006: ProposedMake quantitative measurements of fast ion effects in KEK-ATF.Required for BaselineAddresses Objectives:Investigators:Description:Characterize ion effects 2.2.4.1Experimental studies at KEK-ATF 4.1.1.2Takashi Naito, KEKNobuhiro Terenuma, KEKJunji Urakawa, KEK *

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

2.2.4.I Characterize ion effects in the damping rings

Status as at 20/09/2006: CompletedEstimate ion trapping, rise time of fast beam-ion instability, and ion-induced incoherenttune shifts, taking into account the different regions in each ring. Compare analyticalcalculations with simulation results.Required for BaselineAddresses Objectives:Investigators:Description:Characterize ion effects 2.2.4.1Warner Bruns, CERNDaniel Schulte, CERNFrank Zimmermann, CERN *

Milestones Date InvestigatorsMilestone 1 XXX 200X XX, XX,XX

XX, XX,XX

Milestone 2 XXX 200X XX,XXMilestone 3 XXX 200X XX

COMMENTS