K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Injector Linac
Kazuro Furukawafor Injector Linac
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K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Thanks to the reviewers
Dr. Tsumoru Shintake, OIST, chairDr. Matt Poelker, JLAB
Dr. Sasha Gilevich, SLACDr. Yosuke Honda, cERL/KEK
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K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
40-times higher LuminosityTwice larger storage beam Higher beam
current at Linac20-times higher collision rate with nano-beam scheme
Low-emittance even at first turn Low-emittance beam from
Linac Shorter storage lifetime Higher Linac beam current
Linac challengesLow emittance e-with high-charge RF-gun
Low emittance e+with damping ring
Higher e+ beam currentwith new capture section
Emittance preservationwith precise beam control
4+1 ring simultaneous injection
Mission of electron/positron Injector in SuperKEKB
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Linac Overview
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Linac Upgrade for SuperKEKB
Low emittance RF-gun developmentPhoto-cathode: stability, long-lifetime, quantum efficiency
LaB6, Ir5Ce and other possibilities, 5nC/bunch achievedLaser : high-power, stability, bunch profile management
Nd:YAG media, LD excitation, 1.5mJ / 30ps achieved Fiber laser development for profile control
Cavity : field optimization Disk and washer (DAW) cavity Quasi traveling-wave (QTWSC) cavity
Operation : higher stability and reliability PF injection was tested, longer-term tests, backups, are planned
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BunchCompression
AB
C 1 2 3 4 5HER7.0 GeV 5nC x 220 um
LER4.0 GeV e+4nC x 2
Primary e– for e+3.2 GeV, 10nC x 2
1.1 GeV e+ damping ring
Energy Compression
Bunch Compression
PF2.5 GeV0.1nC x 1New RF-gun
5 nC for e–, 10nC for e+IrCe cathode, Fiber laser, DAW cavity
New e+ Capture with FC
PF-AR6.5 GeV5nC
J-arc1.5 GeV
EnergyCompression
SY2
SY3
Ir5Ce
DAW
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Linac Upgrade Progress towards SuperKEKB
High-charge low-emittance RF gun developmentQTWSC cavity and Ir5Ce
photo cathode works well
Positron generation confirmation for the first timeGood agreement with
the simulation results
Precise alignment for emittance preservationRecovering after earthquakeReaching specification of 0.2mm
Utility upgrade during summer 2014 for electricity (+1.5MW) and cooling water (+1400L/min)
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Signal from primary electron
Signal from positron with opposite polarity
Ir5CeCathode
Quasi traveling wave side couple cavity
Positron generator
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Linac Schedule Overview
6
RF-Gun e- beamcommissioningat A,B-sector
e- commiss.at A,B,J,C,1
e+ commiss.at 1,2 sector (FC, DCS, Qe- 50%)e- commiss.at 1,2,3,4,5 sector
non damped e+ commiss.at 1,2, 3,4,5 sectorse- commiss. at A→5 sectors
damped e+ commiss.at 1→5 Qe+ = 1~4nCe- commiss.at A→5 Qe- = 1~5nC
: Electron
: Positron
: Low current electron
2 nCPhase2
1 nCPhase1
Location↓
Time →
Phase1: high emittance beam for vacuum scrubPhase2,3: low emittance beam for collision
Schedule
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Alignment High-precision alignment was not necessary in PF and
KEKB injections, and it was much damaged by earthquake in 2011.
Instead of flexible-structure girder before earthquake, rigid-structure was adopted with jack-volts and fixed supports.
Reflector pedestals are developed and mounted onto quad magnets and accelerating cavities for laser-tracker measurement.
Iterative measurement and adjustment with 500-m straight laser and position sensors should enable 0.3-mm global alignment.
Laser tracker should enable 0.1-mm measurement within 10-m girder unit.
Displacement gauges, hydrostatic leveling, inclinometer are also employed.
Remote measurement system and girder mover system will be necessary for longer term, and are under development.
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Alignment
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Alignment progress in 2014 For the first time at 3-5 sectors Horizontal axis: sensor number from sector C, 1-4, to
sector 5 (~80 m/sector)
Vertical axis: voltage (~displacement at 0.25~0.5mm/mV)
Some girders were not yet upgraded Moved up to 3 mm not to break vaccuum
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Alignment
Displacement / mV
Sector C Sector 5
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Alignment progress in 2014 For the first time after earthquake at downstream
sectors Several measurements during summer Measurement reproducibility was confirmed up to ~0.2
mm While there existed
several conflicting measurements, consistent scheme has been established
Movement of tunnel by several 10’s of micrometer was observed (→ mover)
Further work necessary in 2015, for alignment and girder replacement 9
Higo et al.
~5mm
~10mm
Alignment
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Positron Generation4-times more positron is required at
SuperKEKB than KEKBSafety measure was taken after cable fire
during the test of Flux Concentrator (FC)New components in
100-m capture section were tested in steps
High voltage tests in tunnel in April
Beam tests with electronin May
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Positron Enhancement
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Positron generation for SuperKEKB
New positron capture section after target with Flux concentrator (FC) and large-aperture S-band structure (LAS)Satellite bunch (beam loss) elimination with velocity bunchingPinhole (2mm) for electrons beside target (3.5mm)Beam spoiler for target protection
Flux Concentrator
e+
5 nC injection e-
10 nCprimary e-
bridge coils
target
beamhole
pulsed ST
DC QM
pulsed QM
side view
spoiler
solenoid
LAS Accel. structure
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positronproductionTarget
Flux Concentrator
BridgeCoils
primary e- beam
e+ beam
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Positron Enhancement
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Positron Generation1) Installation of positron generator for SuperKEKB in
April 2014(Beamline construction since summer 2013)
(positron target, spoiler, Flux Concentrator, bridge coils, LAS structures [x6], DC solenoids [16+13],
e+/e- separator, quads [>90])
2) Commissioning of positron beam, observation of the first positron after reconstruction for SuperKEKB, further improvements expected
3) Oct.~Dec.2014 : Linac commissioningJan.~May.2015 : Construction Jun. : Linac commissioningJul.~Sep.2015 : Construction Oct.~Jan.2016 : Linac commissioning
T.Kamitani
Primary e- [nC]
Positron [nC] Efficiency Parameters
June 2014 0.6 0.12 20% FC 6.4kA, Solenoids 370A, LAS capture field 10 MV/m
Specification(at SY2) 10.0 5.0 50% FC 12kA, Solenoids 650A,
LAS capture field 14 MV/m
DR injection(2017?) 4.0 40% Energy spread acceptance
0.5%
x17 x42 x2.5
Positron Enhancement
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
RF-Gun development strategy for SuperKEKB
Cavity : Strong electric field focusing structureDisk And Washer (DAW) => 3-2, A-1(test)Quasi Traveling Wave Side Couple => A-1 => Reduce beam divergence and projected emittance
dilution Cathode : Long term stable cathode
Middle QE (QE=10-4~ 10-3 @266nm) Solid material (no thin film) => Metal composite
cathode => Started from LaB6 (short life time)
=> Ir5Ce has very long life time and QE>10-4 @266nmLaser : Stable laser with temporal manipulation
LD pumped laser medium => Nd / Yb dopedTemporal manipulation => Yb doped
=> Minimum energy spread
RF gun for low-emittance electron
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
time=2.48098e-009
728 729 730 731 732 733
GPT z
11.3
11.4
11.5
11.6
11.7
Ene
rgy
[MeV
]
Emittance 5.5 mm-mrad
Size 0.4 mm
Energy spread 0.6%
Bunch shape
Gun Exit
5 nC 10 nC
Beam tracking simulation resultRF gun for low-emittance electron
M. Yoshida
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Energy spread reduction using temporal manipulation
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0
0.5
1
1.5
2
2.5
3
0 5 10 15 20 25 30
FWHM (ps)
σE/
E (%
)
Gaussian
Square
5nC10nC
15nC
20nC
20nC15nC10nC5nC
5nC electron 15nCPrimary beam for positron production
t
t
Energy spread of 0.1% is required for SuperKEKB synchrotron injection.
RF gun for low-emittance electron
M. Yoshida
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
5.6 nC / bunch was confirmed Next step: 50-Hz beam generation
&Radiation control 16
Quasi traveling wave side couple cavity
Cascaded frequency doublers
Yb fiber and Yb:YAG think disk laser
Ir5Ce photo cathode
Photo cathode RF gun developmentRF gun for low-emittance electron
Part of multi-pass Amplifier
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
GU_A1 Laser Configuration as of Dec.2014
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RF gun for low-emittance electron
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Photo cathode RF gun improvementCrucial for high-current low-emmittance
beamNew Ir5Ce cathode and new cavity QTWSC
were successfulBasic features were confirmed at 2 ~ 5 HzExpect beam parameter and stability
performance at 50 Hz, with multi-pass amplifiers and cooling system
Resolved the issue of oscillator synchronization
Staged laser system improvements with beam measurement system
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RF gun for low-emittance electron
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
R0 ARC Dispersion: need for investigation
Measurement (dot) compared with expected value (line)
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R36
R16
Commissioning
Preliminary
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Towards the injectionWe didn’t completed the preparation
of routine injection beam for Phase-1We prepare for routine operation while
continueing the development ex. Thermionic gun
Also considering the schedule for radiation control licensesMar.-Jun.2015, Jun.-Oct.2015
Need balance between development, operation, schedule, and budget
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Electron gun rearrangement
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Staged Radiation Control License towards SuperKEKB
Two licenses were approved in June 2014[1] Beam diagnostic station at #A2 just after
gunfor 1250nC/s at 50Hz 2bunches
[2] Beam dump at #28 just before damping ringfor 10nC/s with positrons
Radiation measurements especially at positron generatorIndispensable to estimate radiation at >100 times
higher beamBoth approvedSoon apply for the next license at ~Jun.201521
Electron gun rearrangement
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
RF-gunCavities
KL-A1-B
KL-A1-A Phase shifters
Electron gun rearrangement
Up to Dec.2014.
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Installation of Thermionic GunUnder constructionJan.2015 – May.2015.
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Thermionic gun
RF gun
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Injector Division Group StructureMicrowave (RF): klystron, pulse-modulator, llrf,
(at linac, cERL, STF)Accelerator: structure/cavity, vacuum, magnet,
alignment, cooling water, (devices in tunnel), etc
Controls: computer controls, beam monitors, timing, alignment, etc
Injector: RF-gun, beam monitor, pulsed devices, etcM.Yoshida, X.Zhou, T.Natsui, R.Zhang, (D.Satoh), …
Operation: operation management, safety, etcRoutine/basic operation: out-sourced
Commissioning: traversal group between groups
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KEKB
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Linac Schedule Overview
25
RF-Gun e- beamcommissioningat A,B-sector
e- commiss.at A,B,J,C,1
e+ commiss.at 1,2 sector (FC, DCS, Qe- 50%)e- commiss.at 1,2,3,4,5 sector
non damped e+ commiss.at 1,2, 3,4,5 sectorse- commiss. at A→5 sectors
damped e+ commiss.at 1→5 Qe+ = 1~4nCe- commiss.at A→5 Qe- = 1~5nC
: Electron
: Positron
: Low current electron
2 nCPhase2
1 nCPhase1
Location↓
Time →
Phase1: high emittance beam for vacuum scrubPhase2,3: low emittance beam for collision
Schedule
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
Injector linac schedule and RF-gun
Feb(?).2015 – Jun(?).2015: Phase-1 commissioning Non-low-emittance, 1nC electron/positron beams, without damping ring
(DR) With combination of RF-gun and thermionic gun ex. Electron with 1nC RF-gun, Positron with 6nC (?) thermionic gun
(depends on downstream configuration after DR delay affecting PF/PF-AR injections)
Dec(?).2016 – May(?).2017, Damping ring commissioning 1nC – 2nC positron beam, to/from DR
Jun(?).2017 – Feb(?).2018, Phase-2 commissioning Low-emittance (20mm.mrad, 0.1%), 2nC electron/positron beams, with DR
Low-emittance electron beam with RF-gun, 2nC Primary beam for positron with RF-gun or thermionic gun, 5nC
Oct(?).2018 – …, Phase-3 commissioning Low-emittance (20mm.mrad, 0.1%), 4nC electron/positron beams, with DR
Low-emittance electron beam with RF-gun, 4nC Primary beam for positron with RF-gun or thermionic gun, 10nC
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Alignment
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
SummarySteady progress towards first MR injection
Finishing earthquake disaster recovery in FY2014
Will make staged improvements before 2018
Will balance between final beam quality and staged operation
Will select optimized route depending on available resourcesIncorporate thermionic gun as well as RF gun
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K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
SuperKEKB dual rings
Mt. Tsukuba
InjectorLinac
PF-AR
PF
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Thank you
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB 29
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB 30
K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB
ARC
e– (2.5GeV, 0.2nC)
e− Gun
ARC
e+ Target e+ (4GeV, 4nC)
e− Gun
PF Injection
SuperKEKB-LER Injection e– (3.5GeV, 10nC)
ARC
e– (7GeV, 5nC)
e− Gun
SuperKEKB-HER Injection
ARC
e– (6.5GeV, 5nC)
e− Gun
PF-AR Injection
Damping ring
Event-based Control System
Every20 ms
F.B
F.B
F.B
F.B
F.B
F.B
F.B
F.B
Four PPM virtual acceleratorsfor SuperKEKB project
maybe with additional PPM VAsfor stealth beammeasurements
based on Dual-tier controls withEPICS and event-system
Pulse-to-pulse modulation
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K.Furukawa, KEK, RF-gun review, Feb.2015.Linac Upgrade towards SuperKEKB 34