KEKB/SuperKEKB Linac(and S-, C-, L-, X-bands developments)
Kazuro Furukawa
for Injector Linac, KEK<kazuro.furukawa@kek.jp>

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

1

KEK Electron Accelerator Complex
u Present situation for SuperKEKB and light sources
40x
Luminosity
Belle II

Beam from Injector and Storage Current
SuperKEKB:
7 GeV e2600 mA
4 GeV e+3600 mAPF:
2.5 GeV e450 mA
PF-AR:
6.5 / 5.0 GeV e- 60 mA

LER
4 GeV
SuperKEKB
3 km

HER
7 GeV

PF-AR
6.5 GeV

e– BT
e+ BT

e +, e –High efficiency
e+ generator

Injector Linac
2x beamcurrent

Injector Linac at KEK

PF
2.5 GeV

600 m

Damping
Ring

Low emittance
RF-gunK.Furukawa, KEK, FCC week, Jun.2019.

2

Advances in KEK Injector Linac
Machine Performance Improvement
Challenges towards SuperKEKB
Upgraded Injector for SuperKEKB

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

3

Photon Factory Configuration (1982 –)uElectron injector to dedicated light source
Linac delivered:for PF: 2.5 GeV e–
e- LinacPF

2.5 GeV/c

40 accelerator units were installed
Typical accelerator unit
Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

4

2.5 GeV S-band Linacu Injector for dedicated light source, Photon Factory
vWorld-second dedicated (2nd generation) source after Daresbury
vConstruction: 1978 - 1982, Operation: 1982 - Now

u Certain S-band experiences at universities in Japanvex. 300-MeV 300-Hz linac for nuclear physics

u Foreseen collider project TRISTAN
v2.5-GeV 400-m linac without booster
vQuasi-constant gradient 2-m S-band structuree- Linac

PF

Injector Linac at KEK

2.5 GeV/c

K.Furukawa, KEK, FCC week, Jun.2019.

5

2.5 GeV S-band Structureu Quasi-constant gradientv Disk 2a of 20 mm, 75 micron-step changing from entrance to exit
v5 sets of 2a to disperse transverse modes to avoid beam blow-up

u Electroplating technique to fabricate
vNo brazing, no need for tuning, and cost reduced
v160 structures 40 RF sources installedu Long-pulse injection
vup to 1 micro second, 8 MeV / mu Several different injection modes during 37 years
v Still serving 3000 users / year
v Positron injection to cure ion instability under certain vacuum conditionv Hybrid or shaft mode to serve single-bunch experiments as wellv Simultaneous top-up injection to share the beams
Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

6

TRISTAN Configuration (1986 – 1994)
uElectron positron collider for Top quark
TRISTAN32 GeV/cAR
8 GeV/ce- BT

Linac delivered:for PF: 2.5 GeV e–
for TRISTAN:
2.5 GeV e–
2.5 GeV e+
e+, e- Linac

PF
Shared single injector between
particle physics and photon experiments
Injector Linac at KEK

2.5 GeV/c
K.Furukawa, KEK, FCC week, Jun.2019.

7

500-MeV Positron for TRISTANu Injection partv High current thermionic gunv 119 MHz sub-harmonic buncher for single bunch operation

u The same electroplating structure
vBut combined 4-m structure for higher gradientu Certain end-point experiments in-between injections
vAxion search
vSlow positron experiments for material science and particle
physics
vDetector developments

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

8

KEKB Configuration (1999 – 2010)
uElectron Positron Accelerator Complex at KEK
Belle

KEKB

HER
8 GeV/cPF-AR
6.5 GeV/c

e- BT

Linac delivered:for PF: 2.5 GeV e–
for PF-AR: 3 GeV e–
for KEKB: 8 GeV e–
3.5 GeV e+
e+, e- Linac

e+ BT
LER
3.5 GeV/c
PF
Shared single injector between 4 storage rings
Shared beam transport line between HER & PF-AR
Injector Linac at KEK

2.5 GeV/c
K.Furukawa, KEK, FCC week, Jun.2019.

9KEKB DesignuMaximum re-use of TRISTAN inheritanceuHowever, still many improvements applied, ex.
vMany bunch collisions with dual ring collider³Energy asymmetry for the boost of center of mass of Bs

vFull energy injection³Energy upgrade with SLED RF pulse compressor
w from 2.5 GeV (400 m) → 8 GeV (600 m)

vInjection aperture of 30 ps³Slight RF frequency modification to have an integer relation
w Linac 2856 MHz
w Ring (508.5 MHz →) 508.9 MHz: 10.386 MHz x 275: 10.386 MHz x 49

vAnd so on
Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

10

Advances in KEK Injector Linac
Machine Performance Improvement
Challenges towards SuperKEKB
Upgraded Injector for SuperKEKB

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

11

PEP-II/SLAC and KEKBuWe shared ideas/experiences between
PEP-II and KEKB control rooms³Friendly competition (above plots were on the same day in Oct.2005)
Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

12

Performance improvements at KEKB
uCompetition with SLAC PEP-IIvOne of worries was the injector capability³Injection beam quality³Beam stability³Beam current, especially positron³Injection time to fill the both storage rings³And, integrated luminosity

uMany improvements required, however
vTwo serious damages in accelerator structure in 2001
³after the performance was pushed too hard
³We found our way with optimized performance
Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

13

Operational Optimizations
uFor example, run-length optimization
vOne of 100
automations

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

14

Energy Stabilization Loops
u BPMs - Energy knob
v Energy knob without
energy spreadv Simple
P.I.
Loop

6 feedback loops along the linac depending on the modes

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

15

Feedback Stabilizer monitor
u Robust operation isessential
v Remote monitoring insummary panelv Several conditions,limits in loop variables
v Beam-mode
dependent operationv Status and variable
logging, and theirviewers

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

16

Operation statistics and improvements
Injector operation hours and failure rates

8,000

Operation hours (hour)
Failure rate (%)

Hours

7,000

Beam loss rate (%)

8
7

6,000

6

5,000

5

4,000

4

3,000

3

2,000

2

1,000

1

0

0

Rates (%)

uStatistics

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017

Fiscal year

u Failure: device failures that prevent optimum performanceu Beam loss: time when beam injection was really impossible
Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

17

Two bunches in a pulsevAs the stored beam current in MR increases, much
more injection beam current was required
vEspecially for the positron injection rateuTwo bunches in a pulse acceleration in orderto to double the positron beam current planned
vMinimum bunch separation of 96 ns (10.386 MHz)vParallel dual grid pulsers for a single cathodevBeam instrumentation with 96 ns separationvTiming manipulation and bucket selection
vEnergy equalization

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

18

Energy Equalization
uBeam loading compensation
vFor bunch separation of 96 ns³Or we sometimes utilize
energy difference
in order to equalize
the beam orbits

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

19

Dual-bunch Energy Equalization, and Feedback
u Energy equalization is important for stable operation
Measurement at bunching section
after energy equalization
with RF pulse timing

Stabilization at bending section
with SLED timing

First Bunch

SLEDSecond Bunch

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

20

Continuous Injection
vDetector data acquisition stopped during the injection
and the detector high voltage (HV) preparationvEspecially for the positron injection rateuContinuous Injection with detector HV applied
was another major step forward
vFor higher integrated luminosity
vby detector improvements, esp. CDC, TOF, DAQ
vwith certain benefit from collision with crossing angle³without bending magnet at IP, for lower backgroundvThen, approximately 26% gain achieved

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

21

Continuous injectionua
2004, after continuous injection was applied
Data acquisition continued during injection(8-hour history of beam current, luminosity, etc.)

2003, before continuous injection was applied
Data acquisition stopped during injection(8-hour history of beam current, luminosity, etc.)

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

22

Beam mode switching improvements
uContinuous injection was applied in 2004
Beam mode switching
80000
70000
60000

Count

50000
40000
30000
20000
10000
0
1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

Year

uSwitched 360 times / day in 2008
uSimultaneous top-up injection was applied in 2009
Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

23

Simultaneous Top-up InjectionsvEven faster beam mode switches

uPulse-to-pulse modulation (PPM) at 50 Hz³PPM was first applied at PS/CERN (1977) at 1.2 second

v~150 parameters were switched every 20 ms for 3
beams

uMany Hardware improvements as well as
controls
vPF top-up injection for higher quality experiments
vSensitive luminosity tuning with Crab cavities³Many more parameters in SuperKEKB for 4 beams
Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

24

Dual-layer Controls

Fast Global Synchronous ControlsuEvent-based controls (MRF)
u114.24MHz event rate, 50Hz fiducials
uTiming precision < 10ps

Dual layer control concept
Dual Layer Controls

Event Generator

CentralOPI

EPICS
Channel Access

IOC

IOC

IOC

IOC

EVG

EVR

EVR

EVR

MRF
Event Link

SH_A1
KL_B5/B6

SB_B

Injection

SB_Ae­ GunARC

e– BT (PF: 2.5GeV, 0.1nC)

Cont-ABC
KL_51/52
SB_C

SB_1

SB_2

SB_3

SB_4

SB_5

e+ BT (KEKB: 3.5GeV, 2nC)

e+ Target
Cont-1

Cont-2

Cont-3Cont-4Cont-5

Event Receivers
Injector Linac at KEK

e– BT (KEKB: 8GeV, 2nC,
PFAR: 3.0GeV, 0.1nC)

K.Furukawa, KEK, FCC week, Jun.2019.

25

Dual-layer Controls

One Machine, Multiple Virtual Accelerators (VAs)u Control/Monitor are carried dependent on a VA
v Mostly independent between VAs

u Independent parameter set for each VA, one of the VAs is controlled at atimev VAs for Injections (HER (e-), LER (e+), PF, PF-AR) and Linac-only in SuperKEKB projecte− Gune– BT (PF: 2.5GeV, 0.1nC)

PF Injection

ARC

e+ Target

Event-based
Control Systeme− GunARC

KEKB-LER Injection

Primary e– (4GeV, 10nC)

e+ BT (KEKB: 3.5GeV, 0.6nC)

e+ Targete− GunARC

KEKB-HER Injection
e+ Targete– BT (KEKB: 8GeV, 1.2nC)

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

26

Dual-layer Controls

Multiple Closed Loop Controls Overlappedu Closed loops were installed on each VA independently

e− Gune– BT (PF: 2.5GeV, 0.1nC)

PF Injection

ARC

e+ Targete− GunEvent-based
Control System

ARC

KEKB-LER Injection

Primary e– (4GeV, 10nC)

e+ BT (KEKB: 3.5GeV, 0.6nC)

e+ Targete− GunARC

KEKB-HER Injection
e+ Targete– BT (KEKB: 8GeV, 1.2nC)

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

27

KEKB Operation Improvement (base of SuperKEKB)
red: beam current (e-, e+)purple: vacuum (e-, e+)yellow: luminosity
green: integrated luminosity

Belle/KEK

May.2000
Apr.2003
Dual Bunch e+
Feb.2005
Continuous
Injections
Dec.2008
Crab Cavities andSimultaneous Injection
Injector Linac at KEK

Keeps world
luminosity record
K.Furukawa, KEK, FCC week, Jun.2019.

28

Advances in KEK Injector Linac
Machine Performance Improvement
Challenges towards SuperKEKB
Upgraded Injector for SuperKEKB

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

29

SuperKEKB at 2002
uSome consideration on upgrade forSuperKEKB was presented already in 2002
uMuch different from present form, but thisshows a project needs a long lead timevLater,vEnergy exchange
was rejected
vNano-beam scheme
was employed

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

30

C-band Developments for Energy Exchangeu Electron cloud instability in the positron ring could bepartially cured with higher energy in SuperKEKB

u The same electroplating technique was applied for the
1-m structures, and succeeded doubling the gradient
Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

31

Converting S-band unit into C-band unitsu 2 units were actually installed and operated for injections
during the KEKB project
Existent S-band accelerator module�
Wave guide

Wave guideS-bandSLEDC-bandcompressor

41 MW
4 µs S-band

Pulse
Modulator

New C-band accelerator module�

KlystronS-band accelerating sections

Accel. field gradient = 21 MV/m

40 MW
2 µs Pulse

C-bandModul- Klystron
ator

Wave guideC-bandcompressor

40 MW

Pulse C-band
Modul- Kly- 2 µs
stron
ator

C-band accelerating sections

Accel. field gradient = 42 MV/m

u However, later scheme did not allow small apertures toavoid emittance growth, and removed for SuperKEKB
Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

32

X-band Developmentsu X-band deflector was developed
vFor single-shot emittance measurementvIn collaboration with SLAC
vMedium power klystron and power modulators were developed
vInstallation delayed for beamline designu General purpose high-gradient acceleration studyvIn collaboration with CERN, SLAC, Beijing, Shanghai, …
vEspecially CLIC collaboration and CLIC prototype structure tests

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

33

L-band Developments for Positron Yieldu L-band structure was developed to enhance the positron
yield
vAfter the positron target for large-aperture capturingvAfter the damping ring for bunchingu Kantal coaxial RF load to fit inside of solenoidsu Synergy expected with 1.3 GHz RF ILC developmentv2856 x 5 ÷ 11³"11" is needed anyway for the ring
synchronizationvS-band satellite bunches canbe filtered with this frequency

u Klystron was developed as wellv High power test succeededu Now this is a backup plan
Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

34

Large Aperture S-band Developmentu L-band system may consume large resources
u Beam simulation suggests S-band may sufficevWith velocity bunchingvFor capturing, bunching, and satellite eliminationu Larger aperture S-band structure was designed
v20 mm à 30 mm aperture, double feed, fitting into solenoids
vElectroplating à brazing because of small productions

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

35

Advances in KEK Injector Linac
Machine Performance Improvement
Challenges towards SuperKEKB
Upgraded Injector for SuperKEKB

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

36

Injector Linac Mission

Mission of Electron/positron Injector in SuperKEKB
v For 40-times higher luminosity in SuperKEKB collider
v Low emittance & low energy spread injection beams with 4 times higher beam current³ New high-current photo-cathode RF gun³ New positron capture section³ Positron damping ring injection/extraction³ Optimized beam optics and correction³ Precise beam orbit control with long-baseline alignment³ Simultaneous top-up injection to DR/HER/LER/PF/PFARv Balanced injection for the both photon science andelementary particle physics experiments
Low emittance
RF-gunDamping
Ringe–

Injector Linac

e+

600 m

High efficiency
e+ generator

2x beamcurrent

PF
2.5 GeV

e–

e+ BT

PF-AR
6.5 GeVe – BT

Beam from Injector and Storage Current
SuperKEKB:
7 GeV e2600 mA
4 GeV e+3600 mAPF:
2.5 GeV e450 mA
PF-AR:
6.5 GeV e60 mA

HER
7 GeV

SuperKEKB
3 km

LER
4 GeV

Belle II
40x
Luminosity

Injector Linac at KEK

The single injector would behave as
multiple injectors to multiple storagerings by the concept of virtual
accelerator
K.Furukawa, KEK, FCC week, Jun.2019.

37

SuperKEKB Schedule
SuperKEKB/Belle II schedule
Calendar year

2010

2011

2012

2013

2014

2015

2016

2017

2018

2019

Japan FY

JFY2010

JFY2011

JFY2012

JFY2013

JFY2014

JFY2015

JFY2016

JFY2017

JFY2018

JFY2019KEKB operation




SuperKEKB LER & HER upgrade construction
Start-up

Phase 1w/o QCS
w/o Belle II

Belle II upgrade construction

IR renovation(install QCS, etc.)

Phase 2

Belle II roll-in

w/ QCS
w/ Belle II (no VXD)VXD installation

Positron damping ring (DR) construction

w/ full Belle II

Phase 3
DR commissioning

Injector Linac upgrade construction & operation

Injector Linac at KEK

operation
for years

K.Furukawa, KEK, FCC week, Jun.2019.

38

Linac Beam Property Requirements

Required injector beam parameters
Injector Linac Parameters

Stage

KEKB
Achievements

Phase-I
Achievements

Phase-II
Requirements

Pre- Phase-II
Achievements

Phase-III
1st Year Plan

Phase-III Final
Requirements

Beam
e+
e–
e+
e–
e+
e–
e+
e–
e+
e–
e+
e–
Energy3.5 GeV 8.0 GeV 4.0 GeV 7.0 GeV 4.0 GeV 7.0 GeV 4.0 GeV 7.0 GeV 4.0 GeV 7.0 GeV 4.0 GeV+ 7.0 GeV+Stored current 1.6 A
1.1 A
1A
1A
1.8 A
1.3 A
–
–
3.6 A
2.6 A
3.6 A
2.6 A
Life time
150
200
100
100
–
–
–
–
–
–
6
6
(min.)
primary e- 10

Bunch charge
→1
1
(nC)
Norm.
Emittance
1400
310(γβε) (µrad)
Energy spread 0.13%
0.13%
Bunch / Pulse
22
Repetition rate
50 Hz
Simultaneous
top-upinjection(PPM)

3 rings

primary e- 8
→ 0.4

1000

primary e- 10

1
130

0.50%
0.50%
2
2
25 Hz
No top-up

0.5
200/40

1
150

1.4

2.5

200/5

20 @
SectorB

1-3

100/15

primary e- 10

1-3

40/20

→4

100/154

40/20(Hor/Ver)
0.16%
0.10%
2
2
25 Hz

(Hor/Ver)
?
?
2
2
25 Hz

(Hor/Ver) (Hor/Ver) (Hor/Ver) (Hor/Ver)
0.16%
0.07%
0.16%
0.07%
2
2
2
2
50 Hz
50 Hz

Eventually

Only for LER, PF,
PF-AR

4+1 rings (LER,
HER, DR, PF, PFAR)

4+1 rings (LER,
HER, DR, PF, PFAR)(LER, HER, PF)

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

39

Positron Enhancement

40

Positron generation for SuperKEKB
side view
10 nC
primary e-bridge coils

DC QM spoiler

Y.Enomoto et al.

solenoid
LAS Accel.
structuretargetprimary
e- beam

e+

beam
hole

positronproduction
5 nC injection e-Target
Flux
Concentrator

pulsed ST
pulsed QM

Flux
Concentrator
BridgeCoils
e+ beam

New positron capture section after target with
Flux concentrator (FC) and large-aperture S-band structure (LAS)
Satellite bunch (beam loss) elimination with velocity bunching
Pinhole (2mm) for passing electrons beside target (3.5mm)
Recently, facing discharge difficulties at maximum field
Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

40

One of Key Component: Photo Cathode RF Gun

Development of Photo-cathode RF Gun
M.Yoshida et al.

u Succeeded in injection during SuperKEKB Phase 1 and 2 commissioningu Employs Yb-doped-fiber and Nd/Yb:YAG
laser, Ir5Ce cathode, QTWSC or cut disk
cavitiesu Stability improving
u Beam instrumentation
improvements andcomparison withsimulation codes underway Bunch width
Beam orbit measurementu Secondary RF gun was constructed
as a backup
u Incorporate suggestions by review committee
for availability and so on

Thermionic gun
Primary RF gun

Quasi traveling wave
side couple cavity

Secondary RF gun
Cut disk cavity

Injector Linac at KEK

Ir5Ce
CathodeElectron Guns

K.Furukawa, KEK, FCC week, Jun.2019.

41

Pulsed Magnet Development

Development and installation of pulsed magnets
v Pulsed magnets and power supplies were installed in 2017v >30 quads, >40 steerings, 2 bends, 14 girders are operationalv Quads with advanced design at 1 mH, 330 A, 340 V, 1 ms with energy recovery up to 75%
v Small form-factor of 19 inch width and 3U height each
Enomoto, Natsui et alv Steering power supplies were also developed in-housev Essential for SuperKEKB low-emittance injection and for simultaneous injection
v 4+1 ring simultaneous injections with virtual accelerator concept
Pulsed Quads

Pulsed Correctors³ Successful fast beamswitches³ 0.01% reproducibility andstability³ Girders with In-housedrawings to save resources³ 0.1mm alignment precision³ Long term tests at a stand³ Satisfies specifications³ Control synchronization
Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019. 42

Pulse-to-pulse modulationu Four PPM virtual accelerators
for SuperKEKB project
Based onDual-tier controls withEPICS and event-system

Event-based
Control System

Every
20 ms

F.B
e− GunARC

Independent parameter setsfor each VA (20ms)>200 parameters
for equipment controls
many more
for beam controls
maybe with additional PPM VAof stealth beam
for measurement

F.B

PF Injectione– (2.5GeV, 0.2nC)

F.B
e− GunARC

Damping ring

SuperKEKB-LER Injection

F.B

e– (3.5GeV, 10nC)

F.B

e+ Targete+ (4GeV, 4nC)

e− GunARC

SuperKEKB-HER Injection

F.B

e– (7GeV, 5nC)
e− GunARC

F.B

PF-AR Injection

F.B
e– (6.5GeV, 5nC)

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

43

Residual Dispersion Function in Linac
DesignMeasured

BeforeY. Seimiya et al.
• Large residual dispersion was generated
from the J–ARC.
• With dispersion correction by tuning themagnetic field of quadrupole magnets,
residual dispersion became smallenough.
Measured

After

Dispersion correction

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

44

Simultaneous 4 + 1 Ring Top-up Injection
u Realized for the first time
³ SuperKEKB HER 7 GeV e–³ SuperKEKB LER 4 GeV e+³ Photon Factory 2.5 GeV e–³ PF-AR 5.0 / 6.5 GeV e–v4 beams are modulated at 20
ms PPM
vMore than 200 pulsed devices
were constructed forSuperKEKB, as well as beam
and RF monitors
vInjection noise (background)
were well studied and routinely
adopted from the 3rd week of
May (after a severe fire)
Injector Linac at KEK

337.5 ± 1.6 mA (0.48%)

348.2 ± 1.2 mA (0.34%)

449.9 ± 0.1 mA (0.02%)

55.1 ± 0.2 mA (0.38%)

K.Furukawa, KEK, FCC week, Jun.2019.

45

Summary

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

46

Summary

Summaryu We learned a lot during injector development and operation for 4
decadesu It contributed to achieve the world highest luminosity
u Injection into SuperKEKB is another challenge with higher beam
charge and lower transverse/longitudinal emittanceu Trial and error for a new accelerator may be necessary dependingon many parameters along the accelerator chainu With some Phronesis we can enjoy accelerators
v Phronesis [Greek]: Practical wisdom, Ability to understand the Universal Truth

Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

47

Mt. Tsukuba

Thank you
SuperKEKB
dual rings
PF-AR
PF

700m Injector
Linac

Conference papers at <http://www-linac.kek.jp/linac/>
Injector Linac at KEK

K.Furukawa, KEK, FCC week, Jun.2019.

48