Timing and Event Controls at SuperKEKB Injector and Damping Ring

SuperKEKB damping ring timing systemand event controls for simultaneous
top-up injections for 4 storage rings
Kazuro Furukawa, Hitomi Ikeda, Hiroshi Kaji,
Fusashi Miyahara, Tatsuro Nakamura, Itsuka Satake,
Masanori Satoh, Hitoshi Sugimura, Makoto Tobiyama
KEK, JapanEPICS Collaboration Meeting / KURRI

K.Furukawa, KEK, May.2017.

Timing and Event Controls at SuperKEKB Injector and Damping Ring

Contents
uInjector linac and damping ringuEvent based controls
uSynchronization between linac and rings
uDamping ring timinguConclusions

EPICS Collaboration Meeting / KURRI

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

Particle accelerators at KEK
Mt. Tsukuba

J-PARC(at Tokai Site)(Super)KEKB
PF-AR

ATF

STF
cERL

PF
Linac

EPICS Collaboration Meeting / KURRI

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Injector
Linac
MissionTiming and Event Controls at SuperKEKB Injector andDamping
Ring

Mission of Electron/positron Injector in SuperKEKB
v For 40-times higher luminosity in SuperKEKB collider
v Low emittance & low energy spread injection beam with 4-5 times more beam current³ New high-current photo-cathode RF gun³ New positron capture section³ Damping ring construction³ 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

The single injector would behave as
multiple injectors to multiple storagerings by the concept of virtual
accelerator
EPICS Collaboration Meeting / KURRI

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RF GunTiming and Event Controls at SuperKEKB InjectorPhoto-cathodeand Damping Ring

Development of Photo-cathode RF Gun
u Succeeded in injection during SuperKEKB Phase 1 commissioning for 11 daysu Employs Yb-doped-fiber and Nd/Yb:YAG
laser, Ir5Ce/Ir2Ce cathode, QTWSC or
cutdisk structuresu Stability improving
u Beam instrumentation
improvements andcomparison withsimulation codes underway Bunch width
Beam orbit measurementu Secondary RF gun is being constructed
as a backup
u Incorporate suggestions by review committee
for availability and so on

Thermionic gun
Primary RF gun

New secondary RF gun
Cutdisk cavity

Ir5Ce
CathodeEPICS Collaboration Meeting / KURRI

Electron Guns

K.Furukawa, KEK, May.2017.

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Timing and Event Controls at SuperKEKB Injector Positronand Damping
Ring
Enhancement

6

Positron generation for SuperKEKB
bridge coilsside view
10 nC
primary e-

DC QM

spoiler

Kamitani, Enomoto et alsolenoid
LAS Accel.
structuretargetprimary
e- beame+positronproduction
5 nC injection e-Target

beam
hole

Flux
Concentrator

pulsed ST
pulsed QM

Flux
Concentrator
BridgeCoils

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)
Replacement mechanism even under higher radiation
Resolving recent discharge difficulties at maximum field
EPICS Collaboration Meeting / KURRI

e+ beamK.Furukawa, KEK, May.2017.

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PulsedMagnetDevelopment
Timing and Event Controls at SuperKEKB
Injectorand Damping
Ring

Development and installation of pulsed magnets
v Pulsed magnets and power supplies will be installed in 2017 for resource optimizationv 30 quads, 36 steerings, 2 bends, 13 girders are being fabricated and installedv 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 eachv Steering power supplies were also developed in-house

Enomoto, Natsui et alv Essential for SuperKEKB low emittance injection and simultaneous top-up injections
v 4+1 ring injections with virtual accelerator concept³ Long term tests at a stand³ Satisfies specifications³ Control synchronization³ Beam test with two quads³ Successful fast beam switches³ Switching features are comfirmed

EPICS Collaboration Meeting / KURRI³ Girders are tested as well
³ In-house drawings to save rsc.
³ 0.1mm alignment precision³ Ready for Phase-3 upgrade
K.Furukawa, KEK, May.2017.

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

KEKB Operation Improvement (base of SuperKEKB)SuperKEKB may alsoneed much modification
during operation period

Belle/KEK

May.2000
Apr.2003
Dual Bunch e+
Feb.2005
Continuous
Injections
Dec.2008
Crab Cavities andSimultaneous Top-up Injection
EPICS Collaboration Meeting / KURRI

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

Emittance Preservation
u If Device is off center of the beam
v Focusing magnet (quad) kicks the beam bunchv Accelerating structure (cavity) excites wakefield, to bend the tailu Distorted bunch in banana shapev Emittance dilution or blow-up
v Depending on the beam optics and the beam chargeu Orbit correction and alignment management are crucial
to preserve the emittance along linac
Sugimoto et al.

Beam
Focusing
MagnetAccelerating
Structure
Transverse distribution in time direction

EPICS Collaboration Meeting / KURRI

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KEKB

Timing and Event Controls at SuperKEKB Injector and Damping Ring

Main features of controls at KEKBuEPICS as Main control Software Toolkit
vProvided a robust basis of equipment controls
vReduced software design efforts muchuScripting Languages for Operational SoftwarevSADscript/Tk, Python/Tk, Tcl/Tk used much
³Especially, SADscript as a bridge btw. Accelerator simulation,
Numeric manipulation, Graphic interface and EPICS controls

vBright new idea in the morning meeting could make theoperation much advanced in the evening³Great tool to optimize the operation

EPICS Collaboration Meeting / KURRI

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SuperKEKB

Timing and Event Controls at SuperKEKB Injector and Damping Ring

SuperKEKB ControlsuInherit Good part of KEKB Controls
vEPICS
vScripting languages

uEPICS Channel Access (CA) EverywherevEmbed EPICS control software (IOC) everywhere
possiblevReduce efforts on protocol design, testing, etc

uDual Tier: Another layer in addition to EPICS/CA
vEvent system helps EPICS with another channel/layervAdditional functionality, synchronization and speed
EPICS Collaboration Meeting / KURRI

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Dual-layer Controls

Timing and Event Controls at SuperKEKB Injector and Damping Ring

Dual-tier Controls
uIOC controls via Conventional EPICS CA³Above 1ms, ordered controls

uFast FPGA controls via SFP/Fiber (MRF)³10ps ~ 100ms, 114MHz synchronous controls
OPI
Channel Access
IOC

IOC

IOC

IOC

EVG

EVR

EVR

EVR

FPGA/SFP
EPICS Collaboration Meeting / KURRI

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

Event System for Simultaneous Top-up Injection
uFast, global and synchronous controls
uMRF’s series-230 Event Generator / Receivers
uVME64x and VxWorks v6.8
u114.24MHz event rate,uEPICS R3.14.12 with mrfioc2 devsup 50Hz fiducials
u~50 event timing receivers
uMore than 200 dynamic
50Hz Analog/Timing param.
u~30 FPGA-based event receivers
CentralEvent Generator uMulti/single-mode fiberuTiming precision is < 10ps.
SH_A1
KL_B5/B6

SB_B

Injection

96ns

SB_A

e­ GunARCv < 1ps with external
module.

e– BT (PF: 2.5GeV, 0.1nC)>100nsCont-ABC
KL_51/52
SB_C

SB_1

SB_2

SB_3

SB_4

SB_5

96ns

e+ Target
Cont-1>100nse+ BT (KEKB: 3.5GeV, 2nC)

Cont-2

Cont-3Cont-4Cont-5

Event Receivers
EPICS Collaboration Meeting / KURRI

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

K.Furukawa, KEK, May.2017.

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

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)

EPICS Collaboration Meeting / KURRI

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

Possible Configuration for SuperKEKB
Main Timing Station (MTS)
TTL

KEK
B

Main Rings

EVG

Damping Ring

Event

New design at MTS- # of EVGs: 1→3- Two-layers configuration- Two EVGs in lower-layer

PF-AR
PF

Kaji et al

Three EVGs are operated in
independent sequenceswith different periods.

EVR

EVG

Realize complicated timing
control for SuperKEKB.

EVG

SH_A1
KL_B5/B6

SB_B

Injection

SB_Ae­ GunARC

Cont-ABC
SB_C

KL_51/52
SB_1

SB_2

SB_3

SB_4

SB_5

e+
TargetCont-1

Cont-2

Cont-3Cont-4

EVRs
EPICS Collaboration Meeting / KURRI

Cont-5e– BT (PF: 2.5GeV, 0.2nC)
e– BT (PF-AR: 6.5GeV, 0.2nC)
e+ BT (SuperKEKB: 4GeV,
4nC)
e– BT (SuperKEKB: 7GeV,
5nC)

H. Kaji

K.Furukawa, KEK, May.2017.

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

KEKB (old) Synchronization SchemeuSynchronization Req.

for PF

vKEKB : < 30ps
vPF : < 300~700ps

Linac SHB
114.24MHzPF
Circumference
Correction

Flip-flop
Flipflop

PF Revolution
1.6 MHz

Flip-flop

50Hz

Event
SystemuLinac rf isSynchronized to KEKB
rfuEvent Clock is114.24MHzuWe have to manage

AC Line Sync.

BucketSelection

Event
Systemfor KEKB

Clock
Fiducial
114.24 MHz

SHB1 Phase
Controlx5
RubidiumSG

HER/LER
Injection
Phase Control

571.2 MHz
10 MHzSGx52856 MHzX 49 ÷ 275

KEKB HER/LER
Circumference
Correction

508.89 MHz

HER/LER
BucketSelection

EPICS Collaboration Meeting / KURRI

SHB2 Phase
Control

508.89 MHz

Acc. Phase,
Timing Control

vCircumferencecompensation
vBucket selection
vInjection phase
controls

÷ 512099.39 kHzKEKB Revolution

K.Furukawa, KEK, May.2017.

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

RF Clock Relation

u 2856MHz: Injector linac main RF - following SLAC convention
u 571.2, 114.24MHz: Subharmonic bunchersv Bunching high-charge primary electron beam for positron generation

u 508.9MHz: SuperKEKB ring RF (deep tunnel)
v Integer relations³ common freq. 10.385 == 114.24 / 11 == 571.2 / (11x5) == 2856 / (11x5x5)³ common freq. 10.385 == 508.9 / 49v Continuous circumference compensation (CCC) changes RF clock³ based on closed orbit measurement³ CCC ~ 10-6 / year, ~ 10-7 / dayv Injection timing jitter is only allowed up to 30 ps

u 508.5MHz: PF-AR RF (shallower tunnel)³ CCC ~ 4 x 10-6 / year, ~ 10-7 / day

u 500MHz: PF ring RF (even shallower)³ CCC ~ 2 x 10-5 / year, ~ 4 x 10-6 / dayv Injection timing jitter is allowed up to ~ 700 ps

u Clock synchronizationv Linac and SuperKEKB share the common rubidium clock source
v PF ring or PF-AR is injected based on accidental RF phase coincidence within 700 ps
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Timing and Event Controls at SuperKEKB Injector and Damping Ring

Large delay for asynchronous rings
u Pulsed magnets need ~3 ms pre-trigger
u If EVG programmed carefully, SuperKEKB injections
should be OK as linac and rings are synchronizedu For PF and PF-AR injections, realization of bothaccidental coincidence and large delay may introduce
timing jitter, as the clocks has ~10-6 drifts because ofcontinuous circumference compensationu Needs careful prediction of timings (and RF phase)
vSucceeded in the beam tests

EPICS Collaboration Meeting / KURRI

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

Electron Injection into SuperKEKB
uHow much time we wait for injection
vNeed to fill a bucket which has smaller bunch charge
vThere are 5120 buckets (508.9 MHz) in SuperKEKB HER
vLinac can inject a beam bunch every 49 bucket (10.385
MHz)
v5120 and 49 are coprime / disjoint
vAn arbitrary bucket can be filled within³96.3 ns (10.385 MHz) x 5120 = 493 µs

vHigh-power 50Hz modulator can wait up to 2ms

EPICS Collaboration Meeting / KURRI

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

Positron Injection into SuperKEKB
u Damping ring in the middle
v40 ms damping while linac operate at 50 Hz
vCan accommodate 2 bunches x 2 pulses
v2 bunches in a pulse are separated by 96.3 ns (10.385 MHz)vInjection/extraction kickers rise/fall times are ~100 ns
vHarmonic number of 230 was chosen³ to maximize the freedom, to make the size of the ring smallervAn arbitrary bucket in MR can be filled within³ 96.3 ns (10.385 MHz) x 5120 x 23 = 11.3 ms

vEven though the bucket in DR carefully chosen,>100ns4-bunch arrangement in DR limit the possibilities
vHigh-power 50Hz modulator can wait only up to 2ms

96ns>100ns

96ns

EPICS Collaboration Meeting / KURRI

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

Bucket selection in Phase-2 with DRu Without DR, simply wait up to 5120 x 96 ns ~ 493 μs
v 96 ns : highest common frequency between linac – ringe− GunKEKB

ARCe+ BT (3.5GeV, 0.6nC)

Primary e– (3.5GeV, 10nC)
e+ Target

Kaji et alu 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 pulseFore+ 25Hze‒ 25Hz

Inj.

D.R.

e+ 1

e+ 1

e‒ 2
e+ 3

e+ 1
e+ 3,1Ext.

96ns +e DR (1.1 GeV, 4nC)
>100nse− Gun

e‒ 2
e+ 1

ARC
Primary e– (3.5GeV, 10nC)

e‒ 4

e+ 3

e‒ 4

e+ 5

e+ 5,3

e+ 3

e‒ 6
e+ 5
e‒ 6
EPICS Collaboration Meeting / KURRI>100ns
96ns

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

e+ Target

Can be a big challenge in LLRF precision
K.Furukawa, KEK, May.2017.

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

Damping Ring Timing Requirement
uNeed to change main 508.9 MHz clock ± 50 kHz
vfor beam dispersion function analysis
vshould be disconnected from other clocks

uInjection / extraction kicker need charging trigger~15 ms before firing
vfor extraction beam stability not to blow up in linac

uPulse trains should be provided for BPM
vat revolution frequency (508.9MHz / 230)
vsynchronized to one of the beam bunches in DR

uSeveral other timing signals forvBT BPM, SOR light monitor, Bunch feedback, etc.
EPICS Collaboration Meeting / KURRI

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

Initial DR Event System Planu A bit complicatedand dicussion with equipment group

EPICS Collaboration Meeting / KURRI

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

DR Event Timing Systemu Simplified timing configuration with MRF and SINAP modules

EPICS Collaboration Meeting / KURRI

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

Pulse Train Generator for BPM
uSKI-16115 arbitrary delay repetition pulse
generator
Tobiyama, Ikeda et alvMeet the specifications from BPM hardware
vEVR/MRF or EVE/SINAP can generate those pulse trains
but this dedicatedmodule may play better
role

EPICS Collaboration Meeting / KURRI

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Timing and Event Controls at SuperKEKB Injector andDamping
Ring
New
Schedule

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

Linac Schedule Overview at May.2017
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↓
Beam
Licensesin steps

Low
Emittance
Beams

4+1 Ring
Injections

DR
Commiss.
1 nC
Phase1

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

EPICS Collaboration Meeting / KURRI

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, May.2017.

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

Labview and PXI (off topic)
uPulsed magnet controls, and several othersvLabview local controls³On PXI (cPCI) and Windows as well as cRIO, ~15 systems³Stable ! and runs at 50Hz more than several months³With remote EPICS/CA viewer, and local archiver³Managed by an equipment groupvThis system will be used at least for the initial stage³Whether the control group take care as is … ?

vHope to exchange experiences between users
vAnother discussion is PXI or µTCA to solve
performance issues ?
EPICS Collaboration Meeting / KURRI

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

Conclusion
uInjector linac, damping ring, EPICS control
system, event-based synchronous system arebeing constructed
uPartially confirmed in phase-I commissioning in2016
uPhase-II commissioning is just around the corner

EPICS Collaboration Meeting / KURRI

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

EPICS Collaboration Meeting / KURRI

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Timing and Event Controls at SuperKEKB Injector and Damping Ring

Compatible MRF-Event Hardwareu RF monitor systemv Embedded EVR for event sync. with Vertex-6 and SFP

u LLRF system for damping ringv MicroTCA LLRF module with Vertex-5 and SFP

u Detector interface
v Possible embedded EVR in fast detector-veto system

u SINAP VME and PLC modules for damping ring

VME EVO (EVG)
EPICS Collaboration Meeting / KURRIVME EVE (EVR)

PLC EVR
K.Furukawa, KEK, May.2017.

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