Beam instrumentation
at SuperKEKB
Gaku Mitsuka (KEK)for the KEKB beam monitor group
The 23rd KEKB Accelerator Review
8-10 July 2019

Outline• Overview of the beam instrumentation at SuperKEKB• Recent updates & future prospects in the SuperKEKB beam monitors- Optics measurements by gated turn-by-turn monitors- Beam size measurements by synchrotron radiation monitors- Bunch-by-bunch feedback system- Fast IP-orbit feedback system
Beam abort system wasreported by H. Ikeda.

• Summary2The SuperKEKB beam instrumentation
IP-FB
LABM

LiberaInj. BPM
SRM/XRM

Inj. BPM

DCCT

LiberaSRM/XRM

BxB FBBCM DCCTDCCT
BxB FBSRM
902 BPMs for quadrupoles (137 GTBTs)
218 displacement gauge for sextupoles

Beam instrumentation work well over Phase 2&3!!
3

269

ケーブルの取り付け状態

タが壊れたであろうと推測される QC1LP_D（C）（左）、QC1LE_D（C）：下から撮った図（20181120）

Connection failure in MQC1LE/LP

Adjustment data QC1LE TDR 測定 Tektronix DSA8300

voltage(mV)test cable(s04272B 1m) + S04272B 5m + PE 1.5D semirigid + FeedthroughConnection failure since Jan. 2019

QC1LE-A
QC1LE-D

QC1LE-B
ref. cable without FT

QC1LE-CTDR measurements

249
269

voltage(mV)

w/o FT
MQC1LE-D
229
102.080249

102.280

102.480

102.680102.880103.080103.280time(nSec) 200pSec/div

Adjustment
QC1LP
TDR 測定 at
Tektronix
DSA8300 level.)(“w/oFT”datawastestedgroundtest cable(s04272B 1m) + S04272B 5m + PE 1.5D semirigid + Feedthrough229
102.080102.280

QC1LP-A
102.480
QC1LP-D

QC1LP-B
102.680
ref. cable without FT

QC1LP-C
102.880103.080103.280time(nSec) 200pSec/div

MQC1LP-D

269

MQC1LE-D

w/o FT
MQC1LP-D

Adjustment data QC1LP TDR 測定 Tektronix DSA8300• Most likely the outer conductor was damaged
by strong crimping.

voltage(mV)test cable(s04272B 1m) + S04272B 5m + PE 1.5D semirigid + Feedthrough
QC1LP-A
QC1LP-D

QC1LP-B
ref. cable without FT

QC1LP-C

249
269• Smooth operation with healthy three
voltage(mV)electrodes• Plan to replace with new cables having a

modiﬁed SMA connector in middle August
4229
102.080249

102.280

102.480

102.680102.880103.080103.280102.880103.080103.280time(nSec) 200pSec/div

12mm
229
102.080102.280

102.480

102.680

SuperKEKB Beam Instrmentation
MOPF32

Proceedings of IBIC2013, Oxford, UK

1421B Gated turn-by-turn monitor

Gated turn-by-turn monitors (GTBT)

detectors and will be placed in the same local control rooms
around the rings. Therefore the required characteristics ofthe system will be as follows:! It should not disturb the measurements of normal
narrowband detectors too much. Noise from themonitor, especially switching noise from the fast gate
should be suppressed as much as possible.
! The rise and fall time of the gate need to be shortenough to distinguish the bunch signal to cope withthe minimum bunch separation of 4 ns. Also theisolation to the turn-by-turn line should be large
enough to reject the large power (70dB larger) comingfrom colliding bunches.
! The system should be compact, all-in-one package toSAWspace
filters
save the mounting
and theandfabrication cost.
The block diagram of the gated turn-by-turn monitor
system is shownLog
in Fig. Amplifiers,
1. It has four independent channels
corresponding toADCs
four BPM electrodes. Each channel has afast gate switch, 508 MHz band-pass filters (BPF), low
noise amplifiers (LNA, HMC616) with total gain of 40 dB,
a logarithmic amplifier (ADL5513), a peak-holding circuitwith reset timing input, and a 14 bit ADC (ADS850). All
the timing generation and the data process is done by the
Spartan-6 FPGA (XC6SLX100T-3FGG484) with 128 MB
DDR3 SDRAM. The data and the command is transferredthrough Gigabit Ethernet interface. All the system isinstalled in a 1U size box as shown in Fig. 2.

Fast Gate Switch

Hittite HMC232LP4 has been selected as a SPDT IC. As
the measured switching noise was large, typically 70 mV
peak to peak, and the isolation was not so fantastic, lessthan 67 dB, we have employed a switching-noise
cancelling method [4] which combines 4 SPDT ICs andthree 180-deg hybrids as shown in Fig. 3.

FPGA, DDR3
FPGA,
DDR3
0 deg

180 deg

180 deg

Figure 3: Block diagram of a fast noise-cancelling switch.
The switching noise is subtracted using two pairs of 180deg hybrid, while BPM signal is summed with the samepolarity to reduce the insertion loss. For the turn-by-turnmeasurement, two stages of the SPDT switch are used toFast Gate
SwitchFastgate
switch68 and 69 GTBTs in HER and LER
22 GTBTs added since Phase 2(A)

Log Amp

BPM(A)

2013 by JACoW — cc Creative Commons Attribution 3.0 (CC-BY-3.0)To
0 deg LogRatio
Detector

Hittite HMC232LP4 x 4

To narrowband detector

8 4

14bit
ADC

Fast Gate Switch

RF,
Fiducial
Trigger

180 deg

1GHz LPF
BPM

Log-amps, ADCs

508MHz BPF + LNA• Fast RF switch : Hittite HMC232LP4• Log ampliﬁer : AD ADL5513• ADC : BurrBrown 14-bit ADS850• FPGA : Spartan6 XC6SLX100TTo
0 deg Narrowband
Detector

ADC
TimingGate

Spartan6 XC6SLX00T FPGAGbE Ethernet

DDR3 SDRAM

508MHz narrow band detector (COD)
BPM electrode
Figure 1: Block diagram of the gated turn-by-turn detector.

• Switching noise 2 mVpp
• Fast rise/fall time ~0.6 ns• Good isolation > 80 dB
Figure 2: Photo of the Type-1421 gated turn-by-turn
monitor (prototype).

2(B)

Figure 4: (A) Switching noise; upper trace: to narrowband

5

1

7

via EPICS

DisplayNAFF(phase & amplitude)

Write to output⌫ true |/⌫ true

Amplitude

ICA(spectrum decomp.)⌫true |/⌫true

via EPICS
0.001
0.00090.00080.00070.00060.00050.00040.00030.00020.0001
0

0.018
0.016
0.014
0.012
0.01
0.008
0.006
0.004
0.002
0

10

Amplitude

Amplitude

Data into 6 comp. by ICA (blue = accepted)noiseνyAmplitude

0.04
0.035
0.03
0.025
0.02
0.015
0.01
0.005
0

Amplitude

Amplitude

Analysis server|⌫ meas…

<latexit sha1_base64="551HgMDPKNm8mMEJQANHDD2rYhQ=">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</latexit>

GTBT GTBTIOC
IOC|⌫meas

GTBTs’ data pipeline
0.6

0.5

0
0.1

0
0.1

0
0.1

6
0

250

0.2

0.2

500

0.3

0.2

100

10 2

750

0.4

0.3

0.3

1000
Turns

0.5

0.4
0.5

0.4
0.5

1250
1500

0.4

0.3

0.2

0.1
0

Frequency

0

0

0.1

0.035
0.03
0.025
0.02
0.015
0.01
0.005
0
0

0

Frequency

10 8

10 10

1750
2000

0.2
Frequency

Frequency

0.1

0.1

0.2
Frequency

0.25
0.2

0.15
0.1

0.05
0.2

0.3
0.4
0.5

0.3
0.4
0.5

0.4
0.5

0.3

Frequency

Simulation(50% BG included)

4

FFTW (~1/N)

10 6

NAFF (~1/N2)

Phase advance and β function measurements
HER (Injection kicker in x-plane)

0.4

0.4
0.2

Δφ

Δφ

0.2
0
− 0.2
<latexit sha1_base64="0pAccxqehyXsWV/e7pgpI9kFlYM=">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</latexit>0= 0.07500

1000<latexit sha1_base64="WghHbENPMrA6dMXaDKMDI/sKc+Y=">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</latexit>

0

− 0.4
1500

2000

2500

3000

= 0.17
500

1000

0
− 0.2

Δβ/ β

Δβ/ β

− 0.4
0.8
0.6
0.4
0.2
0
− 0.2
− 0.4
− 0.6
− 0.8

HER (Phase locked loop in y-plane)

1500

2000

2500

3000

0.8
0.6
0.4
0.2
0
− 0.2
− 0.4
− 0.6
− 0.8

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0

Distance from IP (m)500<latexit sha1_base64="UCg3IKL94AKDDjbYneHAo6voDaI=">AAACcHichVG7SgNBFD1Z3/EVtQlYGA2KWISbKPgAQbSxTNSooEF210kc3Je7m4AGf8AfsLAxgoj4GTb+gIWfIHYq2Fh4s1kQFfUOM3PmzD13zsxojiE9n+ghojQ1t7S2tXdEO7u6e3pjff3rnl12dZHXbcN2NzXVE4a0RN6XviE2HVeopmaIDW1/qb6/URGuJ21rzT90RMFUS5YsSl31mSpse7Jkqon5BKUyszuxJKUoiMRPkA5BEmFk7dgVtrELGzrKMCFgwWdsQIXHbQtpEBzmCqgy5zKSwb7AMaKsLXOW4AyV2X0eS7zaClmL1/WaXqDW+RSDu8vKBEbpnq7phe7ohh7p/dda1aBG3cshz1pDK5yd3pP46tu/KpNnH3ufqj89+yhiJvAq2bsTMPVb6A195ej0ZXVuZbQ6Rhf0xP5r9EC3fAOr8qpf5sTKGaL8Aenvz/0TrGdS6clUJjeVXFgMv6IdgxjBOL/3NBawjCzyfO4BTnGOWuRZiStDynAjVYmEmgF8CWXiA0m9ja8=</latexit>0= 0.10
1000

1500

2000

2500

3000

1500

2000

2500

3000

= 0.29500

1000

Distance from IP (m)• β measurements are sensitive to GTBT gain calibration.
• Excitation by injection kicker gives better results than that by PLL,
since PLL limits kick amplitude lower to avoid quick beam loss.

• Extended to investigations on chromatic coupling, K-modulation, etc.
7Synchrotron radiation beam size monitors“Visible” SR monitor
mirror box

Beam pipe

Optical hut

Interferometers for H/V

Gated/Streak
cameraX-ray monitor

Measuring transverse sizes throughthe projected image on sci. screen8

(Horizontal beam size)2 [mm2]Beam size measurements in DR• Horizontal beam size measurements by gated camera•- The Bestﬁt damping time 11.5 ms is consistent with the design value (11 ms).
- Refraction optics in Phase 1-2 was replaced with reﬂection optics in Phase 3.
- Increased light intensity enabled a single-shot measurement.
Bunch length measurements by streak camera- Well damped before the extraction ~40 ms
9Bunch length measurements in HER & LER

MWI sim.
MWI sim.

• HER- Bunch length in Phase 3 increases faster than in Phase 2.

•- Bunch length in Phase 2 is similar with MWI sim. in Phase 3 (thanks to D. Zhou).
LER- Similar results are obtained in the Phase 2 and 3 measurements.
- Sizable discrepancy between measurements and simulation remains.
10Synchrotron radiation beam size monitors“Visible” SR monitor
mirror box

Beam pipe

Optical hut

Interferometers for H/VStreak camera

X-ray monitor

Measuring transverse sizes throughthe projected image on sci. screen
11electrons in the bunch.

Relation between lifetime and measured beam size with bunch
m scrubbing, the lifetime was
Touschek factor
numberofparticles
single scattering between twolength correction for each bump height

Calibration of the X-ray monitors
Touschek factor<latexit sha1_base64="aUUEVCk7jtOkvKe8kBw2Z6a+ewI=">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</latexit>

momentum
acceptance

Relative
momentumspreaddispersion

For a flat beamwith a vs.
veryσsmall
vertical oscillation
Toucheck
lifetimeymPiwinski, 1998
Khan, 2006

ion

2
y,meas =dispersion

2
s

700

1998
HER Piwinski,2019 May
20

Khan, 2006

600
500

𝜎𝑥 , ∆𝑝Τ𝑝 , 𝐹(𝜉)400
Are constants

40

300
Fitting the lifetime with k⌧and 𝜎𝑠 as free parameters,
200<latexit sha1_base64="VHJjroU5biBvsceCg6O4JJnmP/A=">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</latexit>∆𝑝Τ𝑝 , 𝐹(𝜉)nstants
40
Streak camera measurements
or MWI simulation (Zhou)

2y,true +Understanding and reducing σs
is crucial to extract small σy,true.
Beam lifetime (min)Touschek
lifetime

Data
Simulation (best-ﬁt σmeas)

Finite resolution,
Be ﬁlters, etc.

s . 20 µm

with cal from ECK method.
<latexit sha1_base64="nbSgCEBBQwsYmpx6N7mUiSfhTZg=">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</latexit>

100

20 30 40 50 60 70 80 90
σy (µm)Found this parameter
12

Same level as Phase 2 (@βy = 28 m)

New X-ray monitor using Si-pixel sensor
US-Japan Collaboration (U. Hawaii, SLAC, Cornell U., and KEK)

• New system directly catching X rays•

High-speed readout electronics
developed at U. Hawaii

by a silicon sensor can take bunchby-bunch snapshots.
σy per bunch helps understanding of
beam instabilities.

Silicon-pixel detector and spectrometerchips developed at SLAC

Silicon sensor& Cu heatsink
13

Testing Si-pixel X-ray monitor in HER

2019-06-13• Temperature on the Cu heatsink has beenmeasured in the detector box in HER.

• No signiﬁcant temperature increase was foundafter beam on (~4℃ at 900 mA). Air cooling(instead of water cooling) would be good enough.

after 2 weeks• Dose inside the detector box ~15 Gy for 2 weeks• Plan to install Si-sensor and detector in summer

after 2 weeks

shutdown, which will be operated together withthe present camera-based system.

Beam on (300 mA)s
M. Andrew

2 days2019-06-18

2 weeks

2019-06-18

14

XRM meeting

XRM meetingBy 2 FBOFF

Bunch-by-bunch longitudinal feedback
LER by2 at 500 mA• Work with Prof. John Fox in May 2019
• No apparent instability ~1 sec after FB turningoﬀ for ﬁlling by 2 (500 mA) and by 3 (575 mA)
ms are observed in excite• Damping ~1.7-1.9Excite
damp
damp measurements.

LER by2 at 500 mA

6

•

Damp

ExciteDamping rate almost linearly increases as FB gain.
15

8

Fast IP-orbit feedback system
Analogue
down converter

Tsukuba B4

BPM digital LPF andfeedback processor

Steering controller

16Spectrum of canonical kick with FB oﬀ/on
FB on [Kp(proportional)=10, Ki(integral) =1000]

FB off

3rd and 5th harmonics of 230 Hz

0

2k (Hz)

20 dB
0• FB on•200 (Hz)- ~20 dB reduction of the osc. amp. found at 10Hz
- Luminosity drops down probably owing tolarge excitation at 230 Hz.
FB on with changing Kp from 10 to 7
- The peak 230 Hz peak gets tamed andluminosity keeps.
- Reduction power < 30 Hz goes smaller.
17

FB on [Kp=7, Ki=1000]

Comparisons with MATLAB simulations
MATLAB simulation (Kp=10, Ki =1000)

FB on [Kp(proportional)=10, Ki(integral) =1000]
3rd and 5th harmonics of 230 Hz

0

2k (Hz)

20 dB
0

20 dB
200 (Hz)• The MATLAB simulation shows a peak at 260 Hz (cf. at 230 Hz in data).
• Reduction powers are ~20 dB at 10 Hz in both sim. and the measurement.
• Future prospects- Need to understand the origin of the 230 Hz peak
- Trying a new FIR filter with small group delay; changing a delay 1.1 to 0.2 ms
improves a reduction power 11.6 to 20.4 dB at 20 Hz.
18

New ideas• New GTBT monitors- 1st round of prototype testing this year
- Embedded FFT in Zynq FPGA enables realtime phase and amplitudemonitoring etc.

• Injection synchrotron oscillation monitor- checking injection related BGs in both rings with 12-bit resolution or more

• Synchrotron radiation beam size monitors- Good and old interferometers (since KEKB-era) will be renewed.

• Radiation monitors- RADFET+Raspberry pi = realtime and EPICS controllable rad. monitor.
19

Summary• 1 out of 4 channels of each MQC1LE/LP seems damaged, although nosigniﬁcant eﬀect to operation. Replacement with new cables in August.

• No other major problem in the beam monitors, work well over Phase 2&3- Promising capability of GTBTs for optics measurements- Well calibrated beam size monitors provide fundamental information to
the beam commissioning, and may contribute to beam dynamics study.
- Bunch-by-bunch FB system stably operated- Tuning of the fast IP-orbit FB underway, will be involved into daily
operation if necessary• R&D of new detectors are running in parallel.
20

Backup21

Variation among 5 data sets"her" using 1:2"her" using 1:4"her" using 1:6"her" using 1:8"her" using 1:10

Injection kicker (x)5000 turns

0.4

0.2

Δφ

Δφ

PLL (y)2048 turns

0.4

0.2

"her" using 1:2"her" using 1:4"her" using 1:6"her" using 1:8"her" using 1:10

0

0

-0.2

-0.2

-0.4

-0.4

0

500

1000

1500

2000

2500

3000

0

22

500

1000

1500

2000

2500

3000

3500

streak camera

1st turn

2nd turn
10th turngated camera

7ms後

23

10ms後

20ｍs後

50ｍs後

24

A comparison of Phase 1 and 2 XRM measurement
At HER using URA mask

Phase 1Min.

Parameters𝝈𝒚(𝒎𝒆𝒂𝒔)1

22 Jun 2016 I = 188~ 250mA, 𝛽𝑦 = 7.64 𝑚 and 1576 bunches

32 um

2

24 Jun 2016 I = ~20 mA, 𝛽𝑦 = 7.64 𝑚 and 1576 bunches

30 um

Phase 2

1
2
3

𝜎𝑠

16 Jun 2018

I = 20 ~ 16 mA, 𝛽𝑦 = 28 𝑚
250 ~ 230 bunches

26 um

04 Jul 2018

I = 40 ~ 30 mA, 𝛽𝑦 = 28 𝑚
64 ~ 42 bunches

21 um

10 Jul 2018

I = 100 ~ 63 mA, 𝛽𝑦 = 7.64 𝑚
788 bunches

14 um

Phase 1

Phase 2

unit

31.58 ± 0.72

6.6 ± 0.73

um

A good improvement, PSF factoris ~ 5 times smaller than phase 1.
49

• Gate camera data (first to 10th turn)Bunch length measurements in the MR(VC = 8.4 MV)

8

LER Bunch Length

8
7
6
5
4
3

7

Bunch Length [mm]Bunch length (mm)

9

0.5

1

HER Bunch Length

6
5
4
3

y = 4.7099 + 2.3196x R= 0.99469
0(VC = 12.8 MV)

2
1.5 0

Ibunch[mA](mA)
Bunch
currenty = 4.6414 + 1.5287x R= 0.95821

0.5

1

BunchIbunch[mA]current (mA)

• MWI simulation shows thresholds are ~1.9 mA (LER) and 2.7 mA (HER).
• Measured bunch lengthening might be due to potential well distortion.
• The HER result is comparable with the simulation (Zhou and Ohmi), buthuge discrepancy between measurements and simulation remains in the LER.
28

1.5

Blue line: Phase-2, 2018.07.04
Red line: Phase-3, 2019.05.20
8Phase-3, CSR+RW+GW
7.5

Phase-2, CSR+RW+GW

7

σz/σz0

6.5
6
5.5
5
4.5
4

0

0.2

0.4

0.6
0.8
1
Ibunch [mA]

1.2

1.4

1.6

14 modifications during Fall 2018
• Mostly aimed at making the alignment
system more robust• However the funds were released too late
to implement them all before installation• One that we could not do in time wasmaking the primary mirrors so they could
be opened and reset in situ

IP found in 3 of 4 telescopes at first scan• However in a single shift, and before telescope
4 could be examined, a shifter sent all 4
primaries out of tolerance. They could not be
reset because they could not be opened (wetried)• We are modifying the primaries this summer andwe have changed software to set hard limits toprimary movement• Nevertheless the new alignment system much
improved and installation time is halved.

Beam size measurements in DR• Horizontal beam size measurements by gated camera•- The Bestﬁt damping time 8 ms is slightly faster than the design value (11 ms).
- Refraction optics in Phase 1-2 was replaced with reﬂection optics in Phase 3.
- Increased light intensity enabled a single-shot measurement.
Bunch length measurements by streak camera- Well damped before the extraction ~40 ms
33