Development of Timing and Control Systems
for Fast Beam Switch at KEK 8GeV LinacKazuro Furukawa, Tsuyoshi Suwada, Masanori Satoh - High Energy Accelerator Research Organization (KEK)
Artem Kazakov - Graduate University for Advanced Studies (SOKENDAI)
Takuya Kudou, Shiro Kusano - Mitsubishi Electric System and Service
Ge Lei, Guanglei Xu - Institute of High Energy Physics (IHEP Beijing)
The 8 GeV Linac at KEK provides electrons and positrons toPhoton Factory (PF) and B-Factory (KEKB). Simultaneous top-up
injections have been considered for both PF and KEKB rings inorder to improve the injection efficiency and the stability. Fast
beam-switching mechanisms are being implemented, upgrading
the timing and control systems. While the present systemprovides precise timing signals for 150 devices, many of thesignals will be dynamically switched using an event system. A new
scheme has been developed and tested to enable double-foldsynchronization between rf signals. Fast controls of low-level rf,
beam instrumentation, kickers, a gun, and beam operation
parameters will also be upgraded for fast and precise tuning of
those parameters. The system has been developed since 2006,
and is being deployed for the autumn run in 2008.

rf Synchronization Systemx 11

Beam Mode Pattern Buffer

SHB 1

SHB 2

LinacPulse 1

Pulse 2

Pulse 3114.24 MHz

571.2 MHz2856 MHz

Beam Mode 1

Beam Mode 2

Beam Mode 3x5

Pulse n………

Beam Mode nx510.385 MHzx 49

KEKB Ring

Revolution

508.89 MHz

99.39 kHz◆ Every pulse (every 20ms) corresponds to a beam mode.
◆ 10 different beam modes are defined (for KEKB e+, etc).

Delay◆ One beam mode may contain many event codes.

÷ 5120KEKB
CircumferenceCorrection◆ About 50 event codes are defined.

KEKB Bucket
Selection◆ Some events correspond to many functions, and others to specific devices.
◆ Beam pattern buffer length (n) can be 2 to 500 (20ms x 500 = 10 seconds).

Flip-flop
PFCircumference
Correction◆ A new pattern can be loaded at the end of the previous pattern.

Flip-flop◆ Otherwise, the pattern repeats forever.

Selector◆ Pattern generator software arbitrates requests from downstream rings.

PF Revolution
Flip-flop

1.6 MHz◆ There are many pattern rules due to pulse device features and limitations.

BucketSelection
AC Line Sync.

50Hz
114.24 MHz
Event Clock

Event System

Event Generator◆ MRF!s series-230 Event Generator and Event Receivers.
◆ Multi-mode (62 µm) and single-mode (10 µm) fibers.
◆ VME64x standard and VxWorks v5.5.1 (or RTEMS v4.7).
◆ 114.24MHz event rate.
◆ 11 event receivers for now.

KL_B5/B6

KEK
e–/e+Linac(8GeV,600m)

SB_B◆ Timing precision is less than 10ps jitter.

SH_A1

e– BT (PF: 2.5GeV, 0.1nC)

e! GunARC
SB_2

SB_3

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

SB_5e+ Target

Event Receivers

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

Beam Instrumentation

Other sub-systems

CentralCont-3

Rf Controls
Fiber

Event

SB_4

Event
Receiver

VME
VxWorks
EPICS

DAC

Event

ADC
AnalogTimingllrf

Cont-4

Ethernet/CA

Oscilloscopewith Windowsand EPICS

Cont-5

Position&Charge
Beam mode

BPM x 4~6
◆ Slow rf controls are replaced with fast event systems.

◆ DPO7104 can acquire data in 50Hz .

◆ Timing and analog signals are essential for absolute energy,◆ Beam modes are recognized by events through network.

energy spread, and dual-bunch energy equalization.

◆ Clients can monitor data of an interested beam mode.

◆ Signals can be switched pulse-by-pulse.

◆ 100 BPMs are synchronized.

◆ Driver klystrons (SB), energy tuner klystron (KL), and◆ Streak cameras and wire scanners will be synchronized

sub-harmonic bunchers (SH) are managed
by the event system.
◆ rf measurement system will be synchronized to events.

to events as well.

◆ Pulsed bending magnet and pulsed steering coils.
◆ Gun pulser selection, voltage, and precise delay.
◆ Injection septa, and kickers.
◆ Beam orbit and energy feedback systems.
◆ Parameter manipulation, and archiving.
◆ Event system integrity monitor (continuous TDC).
◆ Safety interlocks.