Dr. Junhang Dong (PI) Dr. Robert Lee (Manager) Mr. Liangxiong Li (Ph.D. student)
ILC DR RF Cavity – D. Li DR Workshop, KEK, Japan 1 Design for the DR RF cavities and impedance...
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ILC DR RF Cavity – D. Li ILC DR RF Cavity – D. Li DR Workshop, KEK, Japan DR Workshop, KEK, Japan 1 Design for the DR RF Design for the DR RF cavities and impedance cavities and impedance issues issues Derun Li Derun Li Center for Beam Physics Center for Beam Physics Lawrence Berkeley National Lawrence Berkeley National Laboratory Laboratory February 19, 2007 February 19, 2007 KEK, Japan KEK, Japan
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Transcript of ILC DR RF Cavity – D. Li DR Workshop, KEK, Japan 1 Design for the DR RF cavities and impedance...
ILC DR RF Cavity – D. LiILC DR RF Cavity – D. Li DR Workshop, KEK, Japan DR Workshop, KEK, Japan 11
Design for the DR RF cavities Design for the DR RF cavities
and impedance issuesand impedance issues
Derun LiDerun Li
Center for Beam PhysicsCenter for Beam Physics
Lawrence Berkeley National LaboratoryLawrence Berkeley National Laboratory
February 19, 2007February 19, 2007
KEK, Japan KEK, Japan
ILC DR RF Cavity – D. LiILC DR RF Cavity – D. Li DR Workshop, KEK, Japan DR Workshop, KEK, Japan 22
OutlineOutline
• ILC Damping Ring RF RequirementsILC Damping Ring RF Requirements• RF Cavity ChoicesRF Cavity Choices
─ Superconducting cavitySuperconducting cavity─ Existing successful SC RF cavities that could be usedExisting successful SC RF cavities that could be used
• Cornell 500-MHz single cell cavityCornell 500-MHz single cell cavity
• KEK 500-MHz single cell cavityKEK 500-MHz single cell cavity
• What has been done so farWhat has been done so far─ Scaled Cornell 500-MHz cavity design to 650-MHzScaled Cornell 500-MHz cavity design to 650-MHz
• Short range wakefield simulations (SLAC)Short range wakefield simulations (SLAC)
• Future plansFuture plans• SummarySummary
ILC DR RF Cavity – D. LiILC DR RF Cavity – D. Li DR Workshop, KEK, Japan DR Workshop, KEK, Japan 33
ILC Damping Ring RF RequirementsILC Damping Ring RF Requirements
ILC DRs Main Parameters*ILC DRs Main Parameters*
* M. Venturini, et al, PAC-2007 Proceedings
ILC DR RF Cavity – D. LiILC DR RF Cavity – D. Li DR Workshop, KEK, Japan DR Workshop, KEK, Japan 44
RF Cavity ChoicesRF Cavity Choices
Existing (successful) SC RF cavity designsExisting (successful) SC RF cavity designs• Cornell 500-MHz cavity: WG coupler and HOM dampedCornell 500-MHz cavity: WG coupler and HOM damped
─ Installed and demonstrated successfullyInstalled and demonstrated successfully in CESR-B, 2in CESR-B, 2ndnd generation generation light source (greater than 500-mA)light source (greater than 500-mA)
─ Very heavy HOM dampingVery heavy HOM damping─ Used by other light sourcesUsed by other light sources
Diamond LS (500-mA), CL (300-mA), SSRC (500-mA) and SSRF (300-mA)Diamond LS (500-mA), CL (300-mA), SSRC (500-mA) and SSRF (300-mA)
HOM DampingHOM Damping
ILC DR RF Cavity – D. LiILC DR RF Cavity – D. Li DR Workshop, KEK, Japan DR Workshop, KEK, Japan 55
RF Cavity Choices (cont’d)RF Cavity Choices (cont’d)
Coax coupler and HOM DampingCoax coupler and HOM Damping
ILC DR RF Cavity – D. LiILC DR RF Cavity – D. Li DR Workshop, KEK, Japan DR Workshop, KEK, Japan 66
RF Cavity Choices (cont’d)RF Cavity Choices (cont’d)
• KEK 500-MHz (scaled from 509-MHz) SC Cavity DesignKEK 500-MHz (scaled from 509-MHz) SC Cavity Design─ Successfully used at KEK-B and BEPC-II at IHEP, ChinaSuccessfully used at KEK-B and BEPC-II at IHEP, China
ILC DR RF Cavity – D. LiILC DR RF Cavity – D. Li DR Workshop, KEK, Japan DR Workshop, KEK, Japan 77
KEK-B SC CavityKEK-B SC CavityAchievements at KEK-B (RF frequency = 509-MHz)Achievements at KEK-B (RF frequency = 509-MHz)
ILC DR RF Cavity – D. LiILC DR RF Cavity – D. Li DR Workshop, KEK, Japan DR Workshop, KEK, Japan 88
Niobium on Copper CavityNiobium on Copper Cavity
One cryomodule:One cryomodule: - Two single-cell Nb-on- Two single-cell Nb-on copper cavitiescopper cavities - Frequency: - Frequency: 352 MHz352 MHz - Beam Energy: - Beam Energy: 2.5 GeV2.5 GeV - Beam current: - Beam current: 500 mA500 mA
352-MHz Nb-on-Copper RF System352-MHz Nb-on-Copper RF System
Soleil Light Source:Soleil Light Source:
Possible candidate, but no plan yet to explore further at the momentPossible candidate, but no plan yet to explore further at the moment
ILC DR RF Cavity – D. LiILC DR RF Cavity – D. Li DR Workshop, KEK, Japan DR Workshop, KEK, Japan 99
Turn-Key System from IndustryTurn-Key System from Industry
• Available as a turn-key RF system (based on Cornell Available as a turn-key RF system (based on Cornell design) for light sources (ACCEL)design) for light sources (ACCEL)─ Cryomodule + LLRF controlsCryomodule + LLRF controls
ILC DR RF Cavity – D. LiILC DR RF Cavity – D. Li DR Workshop, KEK, Japan DR Workshop, KEK, Japan 1010
What Have We Done So FarWhat Have We Done So Far
• SLAC has scaled Cornell 500-SLAC has scaled Cornell 500-MHz design to 650-MHz MHz design to 650-MHz ─ Short range wakefield Short range wakefield
simulations using ABCI (Z. Li)simulations using ABCI (Z. Li)
─ No long range (narrow band) No long range (narrow band) wakefield simulations yetwakefield simulations yet
• I found: ILC-INF-003 Notes I found: ILC-INF-003 Notes
greenl_rf_p5mm
-25.0
-20.0
-15.0
-10.0
-5.0
0.0
5.0
10.0
15.0
20.0
25.0
-2.5E-03 -5.0E-04 1.5E-03 3.5E-03 5.5E-03 7.5E-03 9.5E-03
s (m)
W_
L (
V/p
C)
Charge
W_L (V/pC)
Mesh size comparison
-2.5000E+01
-2.0000E+01
-1.5000E+01
-1.0000E+01
-5.0000E+00
0.0000E+00
5.0000E+00
1.0000E+01
-2.5E-03 -5.0E-04 1.5E-03 3.5E-03 5.5E-03 7.5E-03 9.5E-03
S
W_L
coarse mesh
dense mesh
ILC DR RF Cavity – D. LiILC DR RF Cavity – D. Li DR Workshop, KEK, Japan DR Workshop, KEK, Japan 1111
What Have We Done So Far (cont’d)What Have We Done So Far (cont’d)
From the ILC-INF-003 NotesFrom the ILC-INF-003 Notes
ILC DR RF Cavity – D. LiILC DR RF Cavity – D. Li DR Workshop, KEK, Japan DR Workshop, KEK, Japan 1212
Future PlansFuture Plans
• Regardless of recent budget newsRegardless of recent budget news• For the scaled 650-MHz SC cavity design from Cornell For the scaled 650-MHz SC cavity design from Cornell
500-MHz cavity:500-MHz cavity:─ Continue the scaled 650-MHz RF cavity design in collaboration Continue the scaled 650-MHz RF cavity design in collaboration
with SLAC with SLAC ─ Re-visit the scaled 650-MHz design, check if there is a need for Re-visit the scaled 650-MHz design, check if there is a need for
geometry modifications:geometry modifications:• Beam pipeBeam pipe
• RF power couplerRF power coupler
• HOM dampingHOM damping
─ Complete long range wakefield simulations Complete long range wakefield simulations Impedance Impedance spectra with HOM dampingspectra with HOM damping
─ Confirm the impedance meets ILS DR requirements (needs to Confirm the impedance meets ILS DR requirements (needs to impedance threshold for the DRs)impedance threshold for the DRs)
─ Define RF system requirements: RF power + cryogenics + …Define RF system requirements: RF power + cryogenics + …
ILC DR RF Cavity – D. LiILC DR RF Cavity – D. Li DR Workshop, KEK, Japan DR Workshop, KEK, Japan 1313
Future PlansFuture Plans
• In parallel with the work for the scaled Cornell cavityIn parallel with the work for the scaled Cornell cavity─ Lunch collaboration with BEPC-II team at IHEP, Beijing to scale Lunch collaboration with BEPC-II team at IHEP, Beijing to scale
the KEK cavity to 650-MHzthe KEK cavity to 650-MHz• IHEP plans to build a spare 500-MHz SC cavity (based on KEK IHEP plans to build a spare 500-MHz SC cavity (based on KEK
cavity) for BEPC-II from funding from Chinese Academy of cavity) for BEPC-II from funding from Chinese Academy of ScienceScience
• Available resources: man power + SRF research facility at IHEPAvailable resources: man power + SRF research facility at IHEP
• Already received very positive response from IHEP (Drs. J. Wang, Already received very positive response from IHEP (Drs. J. Wang, J. Gao, W. Pan and G. Wang) J. Gao, W. Pan and G. Wang)
─ In addition to repeat the proposed work in the previous slide, In addition to repeat the proposed work in the previous slide, IHEP could be a potential institute of the cavity prototype for IHEP could be a potential institute of the cavity prototype for ILC DRsILC DRs
• Exploring engineering challenges for the cavity and cryomoduleExploring engineering challenges for the cavity and cryomodule
• Significant savings (potentially) Significant savings (potentially)
ILC DR RF Cavity – D. LiILC DR RF Cavity – D. Li DR Workshop, KEK, Japan DR Workshop, KEK, Japan 1414
SummarySummary
• Possible SC RF cavity choices for ILC DRsPossible SC RF cavity choices for ILC DRs• Plans for futurePlans for future
─ Collaboration with SLAC and other institutesCollaboration with SLAC and other institutes─ Collaboration with IHEP, ChinaCollaboration with IHEP, China
• We look forward to working with ILC DR collaborators We look forward to working with ILC DR collaborators and making more contributions, but (honestly) nothing and making more contributions, but (honestly) nothing has been done yet at this moment, the recent ILC has been done yet at this moment, the recent ILC budget news does not look like for us to make a rapid budget news does not look like for us to make a rapid progress in near futureprogress in near future
