Beam diagnostics, Feedback systems
Makoto Tobiyama
KEK Accelerator Laboratory

SuperKEKB BxB FBKEKB COD measurement system

SuperKEKB BxB FBSuperKEKB COD measurement
GatedTbT

Separate HER and LER
BPM systems– Cutoff freq. of LER
chamber lower than
1GHz.

GatedTbT

Continue to use VXI
system with MXI (1/2)
connection.
Selected BPMs havegated turn-by-turn
monitor function.

SuperKEKB BxB FBDigitex 17K94A 509MHz detector
18bit ADC (AD7690)
4:1MUXCPLD(VXI control)• Final tuning to get better S/N,linearity, etc, is in progress.
• Mass production is scheduled inthe next FY.

Direct downconverter with image rejection

SHARC(21369)DSP

SuperKEKB BxB FB

Gated turn-by-turn monitor
509MHz/1GHz narrow band detector, or
medium-band detector (Libera?)

TBT
Data

FPGA(Spartan6)
BPM
Fast gate
switch508.886MHz & FID

BPF&AmpLog
Amp

14bit
ADC

SuperKEKB BxB FB

Switching noiseSuperKEKB BxB FB

Better isolation and switching noise cancellation

Proposed and tested by Dr. T. Naito

SuperKEKB BxB FB

Switching noise

About 1/20 of single SW for CH2

SuperKEKB BxB FB

SwitchingSuperKEKB BxB FBBoard view
Fast Gate SW
Spartan6LX
100T FPGAGbE port

Log amp and14bit ADC

1U size

SuperKEKB BxB FB

IR feedback detector

SuperKEKB BxB FBμTCA size board

SuperKEKB BxB FB

IR orbit feedback
Down
converter

μTCA
Detector

Down
converter

μTCA
Detector

Down
converter

μTCA
Detector

Down
converter

μTCA
Detector

From other feedback
processor (GbE/PCIe)μTCA
backplane(GbE or PCIe)
MCH
GbE
EPICS Channel Access

μTCA Orbit feedback
processor at 2nd MCH
Str. Corr. value(GbE/PCIe)

Fast Steering
Magnet controller(VME?)

SuperKEKB BxB FBFeedback processor board
Virtex5-XC5FX200T(FF1738) FPGAMag PS(SFP)

Matlab/Simulink
with systemgenerator (HDLcoder)

GTX
GTX

GbE Phy
CA

GTX

FIFO

PPC440

DRAM

EPICS
Linux

FMC HPCGTX
GTX

FabricA RX1
FabricA RX2
FabricA RX3

GTXFabricA RX4GTXSuperKEKB BxB FBMight we need medium band detector?
We have bought a Libera Brilliance+with orbit feedback unit to evaluate
the performance.

SuperKEKB BxB FBSuperKEKB Transverse FB planSuperKEKB BxB FBSuperKEKB Longitudinal FB plan

Install L-FB in LER only. HER is optional.
Considering to use 4 DAFNE type kicker, with 2-input, 2-output ports forlarger capture range.

SuperKEKB BxB FB

Bunch position detector prototype

SuperKEKB BxB FBDAFNE FB experiment
Collaboration withSLAC (US-Japn) and
INFN-LNF.

SuperKEKB BxB FBFeedback digital filter(iGp12)•••

Resolution of 8 bits is enough in most case. More bits
should help to enlarge dynamic range to capture large offset
from beam-beam kick.
8 Tap FIR should be enough for the transverse plane.
More taps (32 Tap?) is desirable for longitudinal plane
without (or reduced) downsampling.

SuperKEKB BxB FB

BxB feedback system location (Fuji)

SuperKEKB BxB FB

LER(1604) opticsTune (*.53, *.57)
Phase advance between FB monitor, Kicker– PPU1(U) to PPU2(D): H:62deg, V:53 deg– PPU1(U) to Kicker (include one turn): H 170 deg, V: 177 deg– PPU2(D) to Kicker (include one turn):H 62 deg, V:53 deg

Phase advance from collision point to FB detector– PPU1(U): H: 346deg, V:153deg– PPU2(D):H 48deg, V:205deg

Phase advance from injection point– PPU1(U): H 346 deg, V:43 deg– PPU2(D): H 48 deg, V:95 deg

SuperKEKB BxB FBHER(5605)
Tune (*.53, *.57)
Phase advance between FB monitor, Kicker– PPU1(U) to PPU2(D): H:200deg, V:42 deg– PPU1(U) to Kicker (include one turn): H 145 deg, V: 201 deg– PPU2(D) to Kicker (include one turn):H 307 deg, V:159 deg

Phase advance from collision point to FB detector– PPU1(U): H: 245deg, V:173deg– PPU2(D):H 85deg, V:215deg

Phase advance from injection point– PPU1(U): H 270 deg, V:335 deg– PPU2(D): H 108 deg, V:17 deg

SuperKEKB BxB FBHorizontal tune is near 0.5


Need several turns ofrevolution to observe real kickif the phase relation between
the source and the monitor isnot so good.
Using two feedback loop withbetatron phase advancearound 90 deg might solve thisdifficulty.
PPU２
Horizontal

Simulated horizontal beam oscillation
starting beam-beam kick measured at
PPU1 (Upstream).

SuperKEKB BxB FB

Phase shift by digital filter
PPU2PPU1Creating near 90deg phaseshift in the digital filter makes
the stability limit worse.
LER (PPU1 and PPU2) might
be acceptable.

SuperKEKB BxB FBHER PPU1 (U) situationHER PPU1 (H,V) is not
acceptable.
Considering to move the PPU1to downstream location.

SuperKEKB BxB FB

Bunch current monitor

MAX108 8bit ADC
Spartan6 FGPA
VME 2W size

Bunch current information will besend through reflective memory(real time) to the bucket selection
system during injection period.

SuperKEKB BxB FBSchedule

BPM heads for LER antechamber– 1/2 of needed BPM will be delivered soon. The rest will befabricated in the next fiscal year.

509MHz narrow band detector– Final tuning to improve the performance (S/N, linearity) inprogress.
– Mass production will be starting on next fiscal year.

Gated turn-by-turn monitor– Prototype test is in progress (with many difficulty).
– 2nd trial production might be needed.
– Waiting for the decision by the optics group for the place (andthe total number) of the monitor.

SuperKEKB BxB FB

Schedule (cont.)
Fast orbit feedback– 2nd trial production of the detector (uTCA) is planned in thenext FY.
– Feedback processor unit will also be ready.
– Simulation work using Simulink/Matlab is in progress.

Bunch by bunch feedback system– Feedthroughs (button, high power) will be delivered by E/Mar.
– High power amplifiers (10k-255MHz 500W x 8, 0.8-1.8GHz 500W×8) will be delivered by E/Mar..
– Waiting for the decision of the chamber structure around thefeedback systems to design the vacuum components such asmonitor, feedback kicker.
– iGp12 will be used for the digital filter.
– Continue the collaboration with SLAC and INFN-LNF.

SuperKEKB BxB FBbackup

SuperKEKB BxB FBSuperKEKB BxB FBSuperKEKB BxB FBSuperKEKB BxB FB

SO-DIMM type FPGA(SP6-LX45)

http://www.enclustra.com/en/products/fpga-modules/mars-mx1/

SuperKEKB BxB FBSuperKEKB BxB FBSuperKEKB BxB FBSuperKEKB BxB FB

周波数応答(-10dBm)

SuperKEKB BxB FB群遅延特性SuperKEKB BxB FB

420mVpp(500W)

SuperKEKB BxB FB立ち上がり(240MHz FG)

SuperKEKB BxB FB

SR830の場合SRS
ＳＲ８３０
Lock-inアンプ

sin output
デジタルBPF
099.9kHz

Detection in

AIOで制御GP-IB(LAN-GPIB/ASYN)で制御
位相を読んで、0にするよう周波数をずらすEPICSシーケンサ

SuperKEKB BxB FB

Lock-inアンプ

SuperKEKB BxB FB

gain 0.8、44k-45kステップ

SuperKEKB BxB FB

gain0.8 45k-44kステップ

SuperKEKB BxB FB

Vacuum chamber
Aluminum alloy antechamber cutoff frequency <1 GHz110
Aluminum-alloy duct

2010/8/6

Aluminum-alloy duct46

KEK - BINP MeetingSuperKEKB BxB FBBPM headSuperKEKB BxB FB

Impedance/button output simulation

SuperKEKB BxB FB

RF to No.1 (SW off)

IL~-2.7dB

SuperKEKB BxB FB

RF to No.1 (SW ON)

Isolation~-63dB

SuperKEKB BxB FB

RF to No.2 (SW ON)

IL~-3.96dB

SuperKEKB BxB FB

RF to No.2(SW OFF)

Isolation~-78dB