Injector Linac upgrade status
towards SuperKEKB
Kazuro Furukawa
Injector Linac, KEK

Injector Linac Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

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Linac Upgrade Overview

Mission of electron/positron Injector in SuperKEKB
u 40-times higher Luminosity
v20-times higher collision rate with nano-beam scheme³ à Low-emittance even at first turn³ à Shorter storage lifetime

à Low-emittance beam from Linac

vTwice larger storage beamà Higher beam current from Linac

uLinac challenges
vLow emittance e³ with high-charge RF-gun

vLow emittance e+³ with damping ringvHigher e+ beam current³ with new capture section

vEmittance preservation³ with precise alignment & beam control

v4+1 ring simultaneous injection
Injector Linac Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

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Required injector beam parametersStage

KEKB (final)

Beame+e–e+e–e+e–Energy

3.5 GeV

8.0 GeV

4.0 GeV

7.0 GeV

4.0 GeV

7.0 GeVStored current

1.6 A

1.1 A

1A1A

3.6 A

2.6 A

Life time

150 min.

200 min.

100 min.

100 min.

6 min.

6 min.

Primary e-10nC

Present Phase-I

Primary e- 8nCBunch charge→ 1 nC

1 nC→ 0.4 nC

Norm. Emittance(γβε) (µrad)

2100

200

2400

Energy spread

0.125%

0.125%

No. of Bunch / Pulse

22Repetition rate

50 Hz

Simultaneous top-up
injection (PPM)

3 rings(KEKB e–/e+, PF)

Injector Linac Upgrade towards SuperKEKB

1 nC

SuperKEKB (final)

Primary e-10nC→ 4 nC

5 nC

150

100/20(Hor./Ver.)

50/20(Hor./Ver.)

0.5%

0.5%

0.1%

0.1%

2222

25 / 50 Hz

50 Hz

No top-up

4+1 rings(SuperKEKB e–/e+, DR,PF, PF-AR)
K.Furukawa, KEK, Jun.2016.

3Progressu2010: Beam design and hardware developments
u2011-2014: Recovery from earthquake, mainly
because of soft-structure girder designu2012-: Construction and commissioningu2012-: Step-by-step acquirement of beam licenses
u2016: Phase-1
uContinuous: Light source injectionsu…

Injector Linac Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

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Linac Upgrade Overview

Linac Upgrade Progress towards SuperKEKB (1)u High-charge low-emittance RF gun development
v QTWSC cavity and Ir5Ce photo cathodedevelopments
v Laser development is underway

Quasi traveling wave
side couple cavityIr5CeCathodeu Positron generator commissioningv Good agreement with the simulation resultsv Will solve discharge issues

Positron generatoru Precise alignment for emittance preservation
v Recovering after large earthquake in 2011v Reaching specification of 0.1~0.3mm
v Longer term stability should be solvedu Utility upgrade during FY2014
v for electricity (+1.5MW) and cooling water (+1400L/min)
Injector Linac Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

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Linac Upgrade Overview

Linac Upgrade Progress towards SuperKEKB (2)u High-power microwave modulator upgradesu Low-level RF controls/monitor upgrades
v Pulse-to-pulse modulation (PPM) between 4+1 rings
v More spaces for increased number of devices

u Beam instrumentationv Large/small aperture beam position monitors (BPM)v Precise/fast and synchronized BPM readout systemv Wire scanners and beam loss monitors
v Streak camerasv (Deflectors, etc.)

u Pulsed magnet developments
v ~3 bends, ~30 quads, ~40 steerings
v Even with energy recovery

u Event-based control and timing system upgrades
Pulse magnet tests
v Combination of MRF & SINAP modules
v Essential for PPM operationv Precise timing & synchronized controlsv Bucket selection at DR and MR

Injector Linac Upgrade towards SuperKEKB

SINAP event modules

Beam wire scanner

K.Furukawa, KEK, Jun.2016.

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Bucket selection in Phase-2 with DRu Without DR, simply wait up to 5120 x 96 ns ~ 490 μs
v 96 ns : highest common frequency between linac – ringe− GunKEKB

ARCe+ BT (3.5GeV, 0.6nC)

Primary e– (3.5GeV, 10nC)
e+ Targetu With DR, in order to select arbitrary bucket in MR, have to wait up
to ~4.5 ms, even if a bucket in DR was carefully selectedv Power supply can wait only 2 ms, one of only 2798 buckets in 5120 buckets can beselected, may have to change LLRF condition at latter half of linac every pulse
96ns +e DR (1.1 GeV, 4nC)
>100nse− GunARC
Primary e– (3.5GeV, 10nC)>100ns
96ns

SuperKEKB
e+ BT (KEKB: 4GeV, 4nC)

e+ Targetv Can be a big challenge in LLRF precision
Injector Linac Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

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Schedule

Beam Upgrade and Radiation Controlsu Step-by-step upgrade of beam limits
v Towards 5 nC per bunch in Phase-3

u Beam license applications
vFall 2013, 10 nA at #28 dump, 1250 nA at #A2 dump
vSpring 2014, New utility rooms, 50 nA at #61 linac-end dump
vSummer 2015, 200 nA at #15 positron target
vSpring 2016, 800 nA at #15 target
vBefore Phase-3, 1250 nA at #15 target, 625 nA at #61 dumpu Radiation shield additions …
v For Gun, 180deg-arc, Target, Electron stopper, Collimator, Dampingring dump, Linac-end dump, 5 utility rooms, etc

u Even balancing with PF and PF-AR beam operations
Injector Linac Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

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SuperKEKB master schedule�
・・・�

JFY2010�

JFY2011�

JFY2012�

JFY2013�

JFY2015�

JFY2014�

JFY2016�

JFY2017�

・・・�

Now (Jun, 2016)�

KEKB
operation�
Dismantle KEKB�

Phase 2 commissioning：�
l Low beta* tuning at IP�
l Collision tuning�l Start physics data taking�SuperKEKB upgradeconstruction�
LargeEarthquake�Mar.2011�

Akai, Mar.2016.�
Injector Linac Upgrade towards SuperKEKB

Phase 3：�l Physics run with fullBelle II with VXD�Startup, goes �Phase 1 commissioning
conditioning,as expected even with RF-gun�
etc.�

Phase 1�Phase 1 commissioning：�
l Basic machine tuning�l Low emittance beam tuning�l Vacuum scrubbing�l Started on Feb.1.2016.�
DR commissioning
starts prior to Phase 2�

Phase 2、3�SuperKEKB
operation�DR�

For ~10 years�
Belle II install,�
QCS install�

K.Furukawa, KEK, Jun.2016.

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Schedule

RF-Gun e- beamcommissioning
at A,B-sector

Linac Schedule Overview

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

Phase1: high emittance beam for vacuum scrub
Phase2,3: low emittance beam for collision

Time →Location↓BeamLicenses
in steps

LowEmittanceBeams

4+1 Ring
Injections

DRCommiss.
1 nC
Phase1

Without Top-up: Electron: Positron: Low current electron

Injector Linac Upgrade towards SuperKEKB

non damped e+ commiss.
at 1,2, 3,4,5 sectors
e- commiss. at A→5 sectors

2 nC
Phase24 nC
Phase3

Direct PF-AR BT
damped e+ commiss. Improved
at 1→5 Qe+ = 1~4nC RF gun
e- commiss.
at A→5 Qe- = 1~5nC

K.Furukawa, KEK, Jun.2016.

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Subjects to Consider
Phronesis

SafetyDR ECS/BCS

Timingmonitor

Phase-IISchedule

u Phronesis needed(Greek: Practical wisdom,Ability to understand theUniversal Truth)

BBA

RTL abort

Balance

LLRF monitor

Low emittanceJun.2017
Nov.

DR

u Have to consider
too many subjects !

BPM

Alignment

Temporalmanipulation

1 nC e+Phase-I
Feb.2016

GR̲A1 5nC

Bunch
compression

GR̲A1 8 nC

Resources

GR̲A1 10nC
Laser
development

Energy spread

FC / LAS

PF-AR 6.5GeV

Injector Linac Upgrade towards SuperKEKBPulsed bend

Beamstability

DC FODO

4 nC e+Phase-III
Oct.2018

Availability

Conditioning

PF Top-up

4-ringinjection

StrategicmaintenanceGR̲A1 1nC e-2nC e+

3-ringinjection

Orbit control

Compatible
OpticsGR̲A1 for PF

Pulsed PSdevelopment

Pulsed quad

GU̲3T dual feed
modulator

Equipment
stability

KL/AC̲44
replacement

BudgetPF-AR 3GeV

K.Furukawa, KEK, Jun.2016.

11Alignment

Emittance Preservation
u Offset injection may solve the issueu Orbit have to be maintained preciselyu Mis-alignment should be <0.1mm locally, <0.3mm globally
Mis-alignment leads to Emittance blow-up

Orbit manipulation compensates it

100 samples
Sugimoto et al.
Injector Linac Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

12Injector Linac Energy Management
1.1 GeV
Damping Ringcirc. 136 m

Low emittanceRF gun1.5 GeV

e-/e+ beam with different
bunch charge and energy
are accelerated by 50 Hz
repetition rate.

BCS

3.5 GeV
10nC x 2 (prim. e-)
5nC x 2 (inj. e-)

ECS
3T
RF gune+ target &LAS capture section

chicanePFECSPF-ARHER LER

5 nC x2

4.219 GeVe-HER: 7GeV ePF-AR: 6.5GeV e5nCx1

LER: 4GeV e+4 nCx2

e+ target
1.5 GeVe+1.1 GeV

e-/e+ compatible optics

Injector Linac Upgrade towards SuperKEKB

PF: 2.5 GeV e0.1nCx1

Optics is changed for each pulse by using
pulsed quads (Doublet) & steering magnets
K.Furukawa, KEK, Jun.2016.

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Pulse-to-pulse modulationu Four PPM virtual accelerators
for SuperKEKB project

Event-based
Control System

Every
20 ms

F.B

Based onDual-tier controls withEPICS and event-systeme− 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

F.B

SuperKEKB-LER Injectione– (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 Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

14Injector Beam Commissioning for Phase-1
u Electron beamv Thermionic gun
at the beginningv 1 nC per bunchv 2 bunches per pulse
v 50 pulse per secondu Positron beamv Primary electronwith 7-8 nC per bunchv Positron of 0.7 nC
at linac end
without damping ring

Injector Linac Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

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Progress: RF gun
u MR injection from RF gun during Phase-1 was recommended in thelast gun review, and was planned for May 2016 since the last yearu On May 31, even an unusual centipede (~15cm!!) managed to visit
the operation room to celebrate the first injection into HER

Ibaraki Nature Musium

Injector Linac Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

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Beam from RF gun
u Successful Injection into MR for the first time, on May.31
u And continuing the RF gun operation since Jun.8

Injector Linac Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

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Wire Scanner Measurementu Present beam: 1nC/bunch, 25Hz, 20mm.mrad at the gun,30~200 mm.mrad at the linac end, ? Energy spreadu Phase-2: 2nC/bunch, 50Hz, 20 mm.mrad at the linac end, 0.1% energy spreadu Phase-3: 4-5nC/bunchu Much room to enjoy the improvements
Injector Linac Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

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Injector TalksuRFgun Report, Y. HondauRFgun and Electron Beam, M. YoshidauLaser and RFgun, X. Zhou
uPositron Generation and Beam, T. KamitaniuInjector Alignment, T. HigouInjector Commissioning, M. Satohu(Positron damping ring, M. Kikuchi)

Injector Linac Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

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Summary

Summaryu We learned a lot during KEKB operationu Injection into SuperKEKB is another challenge with higher beam
charge and lower transverse and longitudinal emittanceu Steady progress towards designed injection beam in steps
v Alignment: almost confident on the required precision (0.1-mm local, 0.3-mm
global), need to maintain for longer termv Positron generator: another license test, need discharge analysis
v Thermionic gun: re-commissioned for primary electron for positron generationv RF gun: following recommendations at review meetingsv Need much more radiation shieldu Will balance between final beam quality and progressive operationu Will select optimized route depending on available resourcesv Negotiation with light sources
v Commissioing and development in parallel (no other choices)
Injector Linac Upgrade towards SuperKEKB

K.Furukawa, KEK, Jun.2016.

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Mt. Tsukuba

Thank you
SuperKEKB
dual rings
PF-AR
PF

Injector Linac Upgrade towards SuperKEKB

600m Injector
LinacK.Furukawa, KEK, Jun.2016.

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