Beam Property Management at
SuperKEKB 7-GeV Injector Linac
Kazuro Furukawa, Naoko Iida, Takuya Kamitani,
Shingo Kazama, Takako Miura, Fusashi Miyahara,Yukiyoshi Ohnishi, Masanori Satoh, Tsuyoshi Suwada,
Kazue Yokoyama
KEK, Japan<kazuro.furukawa@kek.jp>
Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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uOverview
uLinacuChallengesuDevice property managementuBeam property managementuConclusion
Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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Linac Upgrade

Beam Property Management at SuperKEKB 7-GeV Injector LinacK.Furukawa, KEK, Oct.2015.

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SuperKEKB Schedule
1999..JFY2010

2011

2012

2013

2014

Initial KEKB was shut down in 2010. Dismantling

KEKB� and construction for upgrade was started.�
SuperKEKB construction�

2015

2016
2017
Now (Oct, 2015)�

…�

Phase 3：- Physics run withfull Belle II with VXDStartup,Phase 1 commissioning：
condition- Basic machine tuning-ing, etc.�
- Low emittance beam tuning
Phase 2, 3
Phase 1
- Vacuum scrubbing
SuperKEKB operation�
Phase 2 commissioning：- Squeezing beta at IP(About 10 years)- Beam collision tuning
DR- Start physics data taking
Installation ofDR commissioning starts
Belle-II and QCS�prior to Phase 2.
Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

4Particle Accelerators

Initial KEKB Operation Improvements, base of SuperKEKB
red: beam current (e-, e+)violet: 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 Injections
Beam Property Management at SuperKEKB 7-GeV Injector LinacStill world highest
Luminosity
K.Furukawa, KEK, Oct.2015.

5Linac Upgrade Overview

Mission of electron/positron Injector in SuperKEKBu 40-times higher Luminosity for insight on the flavor structure ofelementary particlesv 20-times higher collision rate with nano-beam scheme³ à Low-emittance even at first turn³ à Shorter storage lifetimev Twice larger storage beamà Low-emittance beam from Linac
à Higher Linac beam currentà Higher beam current at Linacu Linac challengesv Low emittance e³ with high-charge RF-gunv Low emittance e+³ with damping ringv Higher e+ beam current³ with new capture section designv Emittance preservation³ with precise beam controlsv 4+1 ring simultaneous injection
Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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Linac Upgrade Overview

Designed Beam Properties
SuperKEKB(initial) KEKBHER (e-) Energy (GeV)

7.0

8.0

LER (e+) Energy (GeV)

4.0

3.5

HER(e-) stored current (A)

2.6

1.1

LER(e-) stored current (A)

3.6

1.6

HER/LER beam lifetime (min.)6~200Pulse repetition(max) (Hz)5050

Bunch per pulse

22Emittance (mm⋅mrad)

20100~1000

Beam charge (nC)51

Energy spread (%)

0.1

0.125

Damping ringfor LER (e+)

n/aSimultaneous Top-up

4 rings (SuperKEKB e-/e+,PF, PF-AR)

3 rings (KEKB e-/e+, PF)

Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

Subjects to Consider
Phronesis

SafetyDR ECS/BCS

TimingmonitorPhase-II
Jun.2017

ScheduleDRu Too many subjects !
u Phronesis needed (Greek:
Practical wisdom, Ability tounderstand the Universal Truth)

LLRF monitor

Low emittanceBBA

RTL abort

Balance

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

Pulsed bend

Beam Property Management at SuperKEKB 7-GeV Injector Linac

Beamstability

DC FODO

4 nC e+Phase-III
Oct.2018

Availability

Conditioning

PF Top-up

4-ringinjection

Strategic

maintenanceGR̲A1 1nC e-

2nC e+

3-ringinjection

Orbit control

Compatible
OpticsGR̲A1 for PF

Pulsed PS
developmentPulsed quad

GU̲3T dual feed
modulator

Equipment
stability

KL/AC̲44
replacement

BudgetPF-AR 3GeV

K.Furukawa, KEK, Oct.2015.

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Linac Upgrade Overview

Linac Upgrade Progress towards SuperKEKB (1)u High-charge low-emittance RF gun development
Quasi traveling wave
side couple cavityv QTWSC cavity and Ir5Cephoto cathode works wellu Positron generation confirmation for the first timev Good agreement withthe simulation results

Ir5Ce
CathodePositron generator

Signal fromprimary electron

Signal from positronwith opposite polarityu Precise alignment for emittance preservationv Recovering after earthquakev Reaching specification of 0.3mm
u Utility upgrade during summer 2014v for electricity (+1.5MW) and cooling water (+1400L/min)Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

9Linac Upgrade Overview

Linac Upgrade Progress towards SuperKEKB (2)u High power modulator upgradesu Low-level RF controls/monitorv Pulse-to-pulse modulation (PPM) between 4+1 ringsv More spaces for increased number of devicesu Beam instrumentationv Large/small aperture beam position monitors (BPM)v Precise/fast and synchronized BPM readout systemv Wire scanners and beam loss monitorsv Streak camerasv (Deflectors, etc.)u Event timing control systemv Combination of MRF and SINAP modulesv Essential for PPM operationv Precise timing & synchronized controlsv Bucket selection at DR and MR
Beam Property Management at SuperKEKB 7-GeV Injector Linac

SINAP event modules

Beam wire scanner

K.Furukawa, KEK, Oct.2015.

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Recent works

Recent Works in Progress#15 region

Iron shield

More shields for Phase-III#A1 region

Thermionic gunRF gun

Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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Alignment

Device/Beam Property ManagementChallenges

Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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Alignment

Emittance Preservation and Alignmentu If Device is off center of the beamv Focusing magnet (quad) kicks the beam bunchv Accelerating structure (cavity) excites wakefield, to bend the beam tailu Distorted bunch in banana shapev Projected emittance dilution or blow-up, even 100 times larger³ Depending on the beam optics and the beam chargeu Alignment and orbit correction is crucial to preserve theemittance
Sugimoto et al.

BeamFocusing
MagnetAcceleratingStructure
Transverse beam distribution in time direction

Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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Alignment

Emittance Preservationu Initial offset controls should 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.
Beam Property Management at SuperKEKB 7-GeV Injector LinacK.Furukawa, KEK, Oct.2015.

14SuperKEKB

SuperKEKB Controlsu Inherit Good part of KEKB Controlsv EPICS³ Robust basis, Software design effortsv Scripting languages³ SADscripts, Python, … à Bright new idea to be realized in a dayu EPICS Channel Access (CA) Everywherev Embed EPICS control software (IOC) everywhere possiblev Reduce efforts on protocol design, testing, etc.

u Dual Tier: Another layer in addition to EPICS/CAv Event control system helps EPICS with another channelv Additional functionality, synchronization and speed
Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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

Event-based
Control SystemEvery
20 msF.B
F.B

e− Gunbased onDual-tier controls withEPICS and event-system

ARC

PF Injection

F.B
e− GunARC

Independent parameter setsfor each VA (20ms separate)>200 parameters
for equipment controls
many more
for beam controlse– (2.5GeV, 0.2nC)
Damping ring

SuperKEKB-LER Injection

F.B

e– (3.5GeV, 10nC)

F.B

e+ Targete+ (4GeV, 4nC)

e− GunARC

SuperKEKB-HER Injection

F.Be− Gun
ARC

PF-AR Injection

F.B

e– (7GeV, 5nC)
F.B
e– (6.5GeV, 5nC)

Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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Controls for Beam Propertyu Beam property management
Equipment property management
Calibration, Conversion, Local-closed-loop

Beam controls
Position/Orbit, Charge, Energy, Emittance

Beam/Equip. instrumentation statistics
Online simulation
Collection of qualified databases
Tight group collaborations

Polishing algorithms, databases
Daily operational meetings

Supervisory operational software
Protection systems
Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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Databaseu Collection of databases defines the accelerator machineu Each equipment groupis responsible forits databaseu Controls groupis responsiblefor database
to be appliedin operation

Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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Database (example)uMagnets and power suppliesvbeamline geometry (eqtbl)³including mechanical and effective lengthvhardware static information (mgtbl)vmagnetic field excitation characteristics (mgbtbl)³polynomial function of degree up to nine at linacw Newton's method for inverse functionw many other definitions are used in the ring for precisionw current starts from zero, or starts from maximumvcorrection factors by beam operation (mgbftbl)³data analysis using online simulation code
Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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Beam Feedback Loopsu Equipment has inherent instabilities caused by manysourcesv At the beginning of the KEKB project, we had to install many feedback
loops for beam energy, orbit, charge, etc.
v Simple PID (mostly Proportional and Integral), with limitsv Scripts for prototypes, then ePID on IOCsu SuperKEKB with demanding beam specification may require
further considerationsv Emittance preservationv PPM virtual accelerator (VA) handlinguSimulation VA should help organizing the loops
Beam Property Management at SuperKEKB 7-GeV Injector LinacK.Furukawa, KEK, Oct.2015.

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Energy Stabilizationu Energy instability was sometimes foundv Closed feedback loops wereformedv Beam positions were measured
where dispersion function is largev RF phases at adjacent stations
were changedv Loop parameters were beammode dependentv Energy spread feedback using
multi-electrode monitor was also
implemented
Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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Energy managementuBeam at the end of linac is dependent on …
vmaximum possible energy by accelerating structurevLLRF/beam crest trackingvenergy spread minimization condition by LLRF
vvacuum, discharge, power-supply statistical conditions³reviewed daily to protect equipmentuEnergy profile along linac affects …
voverall beam optics conditionsvemittance, stability, …
Beam Property Management at SuperKEKB 7-GeV Injector LinacK.Furukawa, KEK, Oct.2015.

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Emittance managementuBeam emittance is dependent on …
vequipment alignment, 0.3mm for 500m, 0.1mm for 10m³ alignment drift should be monitoredvinitial orbit to cancel beam profile distortionvbeam energy profile along linac should be keptvbeam position monitors for orbit-drift feedback loopsvPPM operation between very different energies and chargesvbalance between fast/pulsed magnets and static magnetsvcontinuous database improvementvalgorithm should be polishedBeam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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u Database

Implementationsv Initial: Text-based database is read by memory-resident dynamic hashdatabase used by middle-layer controls, with peripheral managementv PPM virtual machines are separated using P.V. naming conventionsv Proper separation of database and algorithms is important for improvementv Goal: Reasonable database management with more compornents intolower-layer controls (in EPICS IOC)u Operational softwarev SADscript environment will handle most of beam optimizationsv Well-designed interface would be provided through channel accessu Needs balance between stability/performance and rapid-prototyping
as the machine usage would change dailyv should be investigated in the commissioning phases I, II and III
Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

24Summary

Beam Property Management at SuperKEKB 7-GeV Injector LinacK.Furukawa, KEK, Oct.2015.

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Summary

Summaryu Beam property management will face another level of challengesu Will start with qualified schemes that was confirmed in initial KEKBu Will make progressive improvements up to Phase-III and so onu Database content quality and separation from algorithm is importantu Well-designed interface is providedu Algorithms for now are in scripts for present performance requirementu Will balance between final beam quality and progressive operationu Will select optimized route depending on available resourcesu With some Phronesis we may enjoy coming beam commissiong

Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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Mt. Tsukuba

Thank you
SuperKEKB
dual rings
PF-AR
PF

600m Injector
Linac

Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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Beam Property Management at SuperKEKB 7-GeV Injector Linac

K.Furukawa, KEK, Oct.2015.

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