Optics Issues
Hiroshi Sugimoto
On Behalf of SuperKEKB Optics&Commissioning Group
SuperKEKB Optics Group
Hiroshi Sugimoto, Akio Morita, Yukiyoshi Ohnishi, Haruyo Koiso

The 26th KEKB Accelerator Review Committee

Introduction•

There was concern in the SuperKEKB lattice design that the machine
performance is easily deteriorated by a tiny perturbation.
Numerical calculation presented in MAC, 2011•

In the recent high-beam-current

Vertical emittance and sextupole offsets.

operation, we are struggling withkeeping machine performance.

•

Optics deterioration due toknown and unknown sources is
the main part of this talk.

12/13-14, 2022

The 26th KEKB Accelerator Review Committee<latexit sha1_base64="5t6SVPgApq5gM001yCf5mX1kWZk=">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</latexit>⇤y =0.3 mm2

Contents- Field drifting of the final focusing quadrupole magnets (QCS)- Beam current dependence of Betatron tunes and orbit at SLY magnets- Optics deterioration due to unknown error sources- 3 BPM analysis for QCS(by Y. Ohnishi)- Summary
12/13-14, 2022

The 26th KEKB Accelerator Review Committee

3

Contents- Field drifting of the final focusing quadrupole magnets (QCS)- Beam current dependence of Betatron tunes and orbit at SLY magnets- Optics deterioration due to unknown error sources- 3 BPM analysis for QCS(by Y. Ohnishi)- Summary
12/13-14, 2022

The 26th KEKB Accelerator Review Committee

4Vertical Tune Drifting in 2021
- It was pointed out in 2021 that the amount of a tune feedback gradually increased.
- The observed tune shift and beta-beating can be explained by QCS field error of ~10-2 %.
- It seems that the drifting starts after QCS startup.
- We suspected drifting of QCS magnetic field after its startup.
Expected beat-beating after correction with QC1s

DK1/K1(QC1RP) = -1.4x10-2 % DK1/K1(QC1LP) = -4.2x10-3 %12/13-14, 2022

The 26th KEKB Accelerator Review Committee5-4 of the quadrupole field of QCS in a few hours.
o theofvariation
of 10
ation
10-4 of thequadrupole
field of QCS in a few hours.
measurementswith theQC1P
R&Dandmagnetthat the quadrupoleents with the QC1P
R&D
magnetfoundand
thatfoundthe quadrupole
field is field is
4 in 7 hours.
s.

Field Drifting Measurement with QCS Prototype

Y. Arimoto- Measurement with different ramp cycles.

at
it is
by flux creep.
sed
bycausedflux creep.
- Field drifting was observed
depending on the ramp cycle.
今回の立ち上げy changing
thepattern
rampingof themagnet.
g
the ramping
ofpattern
the magnet.

- The ramp cycle in the operation was modified considering the results.
今回の励磁パターン
2月15日(2022) に実施
A
0→1640→1600
A
0→16000→1600
A
0→1640→1600A
QC1RP in 2022ab
Ramp cycle adopted
Up RampDown Ramp• プロトタイプの測定結果にもとづき• 励磁パターン
1. 設定電流の2.5 %増しで励磁

ofVariationVariationof-4 0.2x10
2
per 10-4 per 10
K1 /K1 = 0.2 ⇥ 10 0.2x10%
3. 再び設定電流の2.5%増しで励磁
hours hours
after ~10 hours
2. 0 Aに下げる<latexit sha1_base64="feBONTucaqoAA6hnpMvHNoEZrz8=">AAADgXichVJLaxRBEK7N+IjrIxu9CF5Gl/VxcK1ZQhRFCOpB8JKHmwSycZlpO5sm86KndzEO8QcInj14UvAgHr3qyYt/wEN+gniM4MWD3/QOiIaMPUz119XfV91dVUEaqsww79YmnEOHjxydPFY/fuLkqanG9OnlLBlqIbsiCRO9GviZDFUsu0aZUK6mWvpREMqVYOtusb8ykjpTSfzQbKdyPfIHsdpQwjdw9RuXevdkaHz3Qd9zrxXmtsvtTs+oSGaux4/yq50d91mv1W80uc12uPuBV4ImlWM+ma6dpx49poQEDSkiSTEZ4JB8yvCtkUdMKXzrlMOngZTdl7RDdWiHYEkwfHi3YAdYrZXeGOsiZmbVAqeE+DWULrX4K7/jPf7C7/kb/zowVm5jFHfZxhyMtTLtTz0/u/Tzv6oIs6HNP6oKRQD2wW/KYTVwimhFBp5UcjP4A9oAcwCkK7OV0whWg+/b7FbfoqiLsO8SlTxhmUXuq+tkcMsbtj4K9Uqtp6icGOds9PTl3tLNxVZ+kd/wd9TsNe/yZ1QtHv0Qbxfk4iuqo+u8f3tsP1jutL3Z9szCTHPuTtl/k3SOLtBl9Nh1mqP7NE9dnPuCPtBH+uQ4zhWHnc6YOlErNWfor+Hc+g36vcVY</latexit><latexit sha1_base64="wgr4WLnxMz9lpNDc82/hjlgZAm0=">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</latexit>

K1 /K1 = 3 ⇥ 10 2 %after ~7 hours

1640 A

4. 2.5%下げて電流設定

0A(各電流値で2分間保持)
12/13-14, 2022

1600 A

Current [A]以下のパターンで励磁

対象主四極磁石: QC1LP, QC1RP, QC1LE, QC1RE
The 26th KEKB Accelerator Review Committee

0A

Time [min]6Tune Drifting before&after the Change of Ramp Cycle- Tune drifting after QCS startup is much reduced in 2022 owing to the modified ramp cycle.

2021

12/13-14, 2022

2022

The 26th KEKB Accelerator Review Committee

7

Contents- Field drifting of the final focusing quadrupole magents (QCS)- Beam current dependence of Betatron tunes and orbit at SLY magnets- Optics deterioration due to unknown error sources- 3 BPM analysis for QCS(by Y. Ohnishi)- Summary
12/13-14, 2022

The 26th KEKB Accelerator Review Committee

8

Pilot Bunch Tune and Total Beam Current

HER- According to beam study in KEKB era,
It was considered that resistive wall tune shift is dominant in HER.
- In 2022ab, beam current dependence of tune shift is estimated by the amountof a tune feedback system.
KEKB
Y. Ohnishi,
Review 2007
Dependenceof Total
BeamKEKB
Current
Y. Ohnishi / KEKSuperKEKB
04/26 2022

Tune shift due to a quadupole field induced by resistivewall of a chamber in HER. The cross section of thechamber is non-axisymmetric.
<latexit sha1_base64="fg8loFh1WrnfkszJn/UU/VFZsNY=">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</latexit>d⌫y /dIb = 0.025

Cross section of HER chamber
50 mm
104 mm<latexit sha1_base64="xG/MivVOkIjm6hmLeym3cACGFIs=">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</latexit>d⌫y /dIb =0.029

T. Ieiri et al., Proc. APAC2001

horizontal tune shift: Δνx = +0.026/ A
 vertical tune shift:Δνy = -0.037/ A


12/13-14, 2022

6
The 26th KEKB Accelerator Review Committee

9Day to Day Variation

HER- Horizontal tune shift does not depend on days, while vertical tune shift depends on days.

0.035Horizontal

Vertical
03/28 2022

0.030

03/29 2022
04/04 2022
04/05 2022

0.025

04/10 2022
04/11 2022
04/26 2022

∆νx

0.020

04/27 2022
04/30 2022
05/06 2022
05/07 2022

0.015

05/08 2022

0.010
- Other sources of vertical tune shift was suspected.

0.005

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

10

Sextupole Magnets for LCC (SLY)- Sextupoles pair connected by a – I ’ transform are installed in both side of IR.
- Horizontal orbit change at SLYs could cause large vertical tune shift.
p

x [

p

y [

p

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LER

m]

HER

m]

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I0<latexit sha1_base64="ubybMh6HhunBiYHq2NGsw6IsnVc=">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</latexit>

I0<latexit sha1_base64="ubybMh6HhunBiYHq2NGsw6IsnVc=">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</latexit>

I0<latexit sha1_base64="ubybMh6HhunBiYHq2NGsw6IsnVc=">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</latexit>

I0

SLY pair in Right-side

SLY pair in Left-side

SLY pair in Right-side

SLY pair in Left-side

SLYTRP1 and 2

SLYTLP1 and 2

SLYTRE1 and 2

SLYTLE1 and 2

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

11Tune Shift due to Horizontal Beam Orbit at SLY Pair
- Horizontal orbit Dx at SLY pair and tune shift
Sine-like orbit

Cosine-like orbit<latexit sha1_base64="3WuJA0dakcpLf6I9QXY6O7mWGbI=">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</latexit><latexit sha1_base64="3WuJA0dakcpLf6I9QXY6O7mWGbI=">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</latexit><latexit sha1_base64="p4LMZi12QrkGMy37JJaXWI6aQlQ=">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</latexit>=⇡⌫x,y = ± x,y (K21 + K22 ) x/4⇡

<latexit sha1_base64="wqn6AaxXmczHkvc4ihCh4YcYth4=">AAADlXichVLNThRBEK5lFGFVWPSAiZfBDQYSXXo2GzUaEqLEkHCQHxdIGJj0NM3aYX46Pb2bXSe8gC/gwRMmHgiP4UGPcuDAIxiPmHjxYE3vJEYJQ0+muvrr76vuripfBiLRhJyWBqwrVwevDQ2Xr9+4OTJaGbu1lsRtxXiTxUGsNnya8EBEvKmFDviGVJyGfsDX/b0X2f56h6tExNFr3ZN8K6StSOwKRjVCXuWZO88DTW03antp90Fv3561XRm6Pte0D0wtbjte/eHidt2rT+fs7kzDlcKrVEmNmGGfd5zcqUI+luKx0gS4sAMxMGhDCBwi0OgHQCHBbxMcICAR24IUMYWeMPsc9qGM2jayODIoontoW7jazNEI11nMxKgZnhLgr1BpwyQ5IYfkjHwlR+Q7+X1hrNTEyO7Sw9nva7n0Rt/dWf11qSrEWcObv6oChY/si9+UolXoS4yWZaBbyE0Q92EXmS30VGG2UuigVcinJrvFt8jqwsy7WCGPGWaW++I6abzlE1MfgfWSBskqx/o567x9f7b6dGUyvU8+kh9YswNySj5j1aLOT/Zpma98gDJ2nfN/j5131uo151Gtsdyozj3P+28I7sI9mMIeewxzsABL0MRzD+ALfINja9yateatl33qQCnX3IZ/hvXqD1cWzts=</latexit>=⇡⌫x,y = ± x,y (K21

K22 ) x/4⇡

- Only cosine-like orbit causes tune shift in non-CW case because of K21 = K22<latexit sha1_base64="FwX8co1lCis0w87wWknqEtkD2yQ=">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</latexit>- Assuming cosine-like orbit of 10µm in HER, for example,
x = 10 µm* Only 10 µm orbit can cause⌫y ⇠ 0.009
y ⇠ 700 m<latexit sha1_base64="DnEONxCD6kWrFU9JupbvzxQsukc=">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</latexit><latexit sha1_base64="/dudu5a+57WHzsxSPlShUSXokwQ=">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</latexit><latexit sha1_base64="3mSCo5O7vFqbdENgft+cbSx522c=">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</latexit>

K21 + K22 ⇠ 16 m 2<latexit sha1_base64="slGCk1YYuwOaj9rITo9Mfd1Zg3c=">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</latexit>

12/13-14, 2022

sizable tune shift.

The 26th KEKB Accelerator Review Committee

12Tune Shift Estimation using Model Lattice- Beam orbits at SLYs are imported to the model lattice as misalignments of the SLYs
- Betatron tunes are evaluated by the model lattice with the misaligned SLYs.

Gray: Horizontal

Black: Vertical

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

13Comparison with Measured Tune Shift
Blue: Measured horizontal tune shift
Red: Measured vertical tune shift
Gray: Estimated horizontal tune shift
Black: Estimated vertical tune shift- Beam current dependence of horizontal orbit at SLYs reproduces
the measured vertical tune slope.
- Where is resistive wall tune shift in vertical direction? -> No clear explanation so far.
12/13-14, 2022

The 26th KEKB Accelerator Review Committee

14Day to Day Variation

HER- The variation of vertical measured tune shift is consistent with that of orbit at SLYs.
High Bunch Current Study

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

15

Estimated Optics Distortion due to Orbit at SLY Magnets
HER
LER- Orbit at SLYs causes not only tune shift but also beta-beating.
- Vertical beta function at the waist becomes smaller as beam current becomes higher.
-> It indicates that we operated SuperKEKB with y⇤ < 1 mm without knowing.
<latexit sha1_base64="iYwv/tPwF+sm/1Oa9zpXlMeaG3w=">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</latexit>

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

16

SLY Orbit Tuning with Orbit Bump
- Bump orbit at SLY is applied tocompensate current dependence of

Initial orbit tuning on 05/15 2022, Ib=800 mA~20 µmhorizontal beam position.
SLYTLE1- The orbit tuning improves injection
efficiency and reduces beam background.

SLYTLE2

Horizontal orbit

Injection Efficiency- We now watch the beam position at SLYs
carefully in the operation.

Beam background- The orbit adjustment in advance to optics
correction reduces # of iterations of theBeam backgroundcorrection.
12/13-14, 2022

The 26th KEKB Accelerator Review Committee

17

Contents- Field drifting of the final focusing quadrupole magnets (QCS)- Beam current dependence of Betatron tunes and orbit at SLY magnets- Optics deterioration due to unknown error sources- 3 BPM analysis for QCS(by Y. Ohnishi)- Summary
12/13-14, 2022

The 26th KEKB Accelerator Review Committee

18

Earthquake (EQ)
- Japan is a country of many EQs.
- EQ causes beam abort in most cases.
- HER beam becomes unstable after EQ in some cases.
- Global optics correction is necessary to recover the stable operation.
- Skew quadrupoles at sextupole magnets and/or QCS can
explain the observed XY-coupling distortion, but there is no direct evidence.
Beam current

KEK campus

Expected XY-coupling after correction withskew quadrupoles at QCS

Earthquake

Luminosity
Verticalemittance
Injection
efficiency

Optics correction
IP parameter tuning

Beambackground
12/13-14, 2022

The 26th KEKB Accelerator Review Committee

19

Optics Degradation with Time- Originally, optics correction is performed every other week (maintenance day)- Recently, we observe the optics degradation when we try high-beam-current operation.
- It seems that beam abort andrecovery from the abort somehowchange machine conditions, andwe can not recover the beam optics.
- Reason of the degradation is notunderstood yet and we need toperform optics correction every
2 or 3 days.

12/13-14, 2022

Luminosity
Vertical emittance in HER
Injection efficiency in HER
Beam backgroundThe 26th KEKB Accelerator Review Committee

20Orbit Fluctuation and Drifting- A possible reason for the optics degradation is orbit fluctuation and/or drifting.
- Numerical estimation indicates that orbit at strong sextupole of a few ten µm
is not negligible.

Example of orbit drifting at sextupole in arc section

cf. Residual of closed orbit correction is20~30µm in RMS.

Horizontal orbit at a sextupole magnet
Blue: Cosine-like component
Green : Sine-like component
Vertical orbit at a sextupole magnet
Red: Cosine-like component
Orange : Sine-like component

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

50 µm

21

More Examples

HER- BPM reading depends on not only real beam orbit but also various effects such as, gain drifting,beamline deformation, air temperature, beam current dependence of the BPM system, etc.
- We need to deal with these effects to discuss real beam position change.
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The 26th KEKB Accelerator Review Committee

22

Contents- Field drifting of the final focusing quadrupole magnets (QCS)- Beam current dependence of Betatron tunes and orbit at SLY magnets- Optics deterioration due to unknown error sources- 3 BPM analysis for QCS(by Y. Ohnishi)- Summary
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The 26th KEKB Accelerator Review Committee

23

ML

M
MR

BPM1

BPM2
BPM3

Estimated BPM3-readingof BPM Reading
3 BPM Analysis Estimationfor QCS

Y. Ohnishi

Slope is not 1.
-> Something wrong.

Slope~1 -> OKActual BPM3-reading- Comparison of BPM3’s readings and that estimated by BPM1 and BPM2.
- The correlation between them reflects difference between the model and real lattices.
- We tried to inspect QCS only using existing orbit data.
No dedicated measurement was performed.
12/13-14, 2022

The 26th KEKB Accelerator Review Committee

24Analysis Example #1

HER

Y. Ohnishi

BPM1: MQLC2RE (out of IR )BPM2: MQLC2LE (out of IR )Estimated reading[mm]

BPM3: MQC1RE (in IR)

BPM1

Horizontal direction

Vertical direction

Slope ~ 1

Slope ~ 1

Actual reading [mm]12/13-14, 2022

BPM3

BPM2

- The slope is roughly 1, and it looks fine.

The 26th KEKB Accelerator Review Committee

25

Analysis Example #2
BPM1: MQC2RE (in IR)
BPM2: MQC2LE (in IR)

HER
BPM1

BPM2

[mm]

BPM3: MQC1RE (in IR)
Estimated reading

Y. Ohnishi

BPM3

Horizontal direction

Vertical direction

Slope is not 1

Slope is not 1

Actual reading [mm]
QC1LE K1: +3.15 %- Numerical simulation indicates that the field error of QC1RE K1: -3.15 % can reproduce
the measured slope. Error in the IR modeling? It is still under investigation.
12/13-14, 2022

The 26th KEKB Accelerator Review Committee

26Summary- Recent high-beam-current operation highlights difficulties in keeping machine condition.
-> Obstacle to both efficient physics experiments and systematic beam study.
- Tune drifting after QCS startup was pointed out in 2021.
-> The drifting is much reduced in 2022 by modifying the ramp cycle.
- Optics deterioration due to the beam orbit fluctuation at SLYs was recognized.
-> The mechanism of the beam current dependence of the orbit is not understood yet.
Beamline deformation due to SR and/or HOM heating?
Some experiments is ongoing to clarify the actual movement of magnets, chamber and BPM.
- Optics deterioration in a few days is one of the largest concerns in daily operation.
-> It seems that a few ten microns orbit change at strong sextupole is not negligible.
Investigation on source of orbit fluctuation including BPM system itself is ongoing.
- 3-BPM analysis implies large error sources in HER IR.
-> Correction to the IR modeling and/or real machine is probably necessary.
12/13-14, 2022

The 26th KEKB Accelerator Review Committee

27

Spare Slides

Beam Orbit at SLYs and Optics Distortion - Model Calculation 0.3

Cosine-like

1.4
1.2

βy @ waist [mm]SLYTLE++SLYTRE++SLYTLE+SLYTRE+-(∆βy /βy )rms [%]

40

30

20

10

0

Vertical waist position ∆s [mm]

HER

50

10

20

30

40

0.8
0.6
0.4

Sine-like
0

1.0

0.2
0

50

50

40

50

30

20

1.00

0.95

10
0.90
0

0

10

20

30

40

Horizontal orbit at sextupoles [µm]12/13-14, 2022

50

0

10

20

30

40

Horizontal orbit at sextupoles [µm]The 26th KEKB Accelerator Review Committee

0.1
0.0
−0.1
−0.2
−0.3
0

10

20

30

40

50

Horizontal orbit at sextupoles [µm]1.05

βy @ waist [mm](∆βy /βy )rms [%]

30

1.10

40

SLYTLP++SLYTRP++SLYTLP+SLYTRP+-

20

Vertical waist position ∆s [mm]

LER

10

Horizontal orbit at sextupoles [µm]

Horizontal orbit at sextupoles [µm]

0.2

50

0.06
0.04
0.02
0.00
−0.02
−0.04
−0.06
0

10

20

30

40

50

Horizontal orbit at sextupoles [µm]29Beam Orbit at SLYs and Optics Distortion - Model Calculation HER

50

30
20

0.4

1

0.2

∆r2 @ IP [mm]∆εy [pm]

SLYTLE++SLYTRE++SLYTLE+SLYTRE+-∆r1 @ IP [ × 10−3]

Cosine-like

40

2

0

−1

Sine-like

10

−2

0.0
−0.2
−0.4

0
0

10

20

30

40

0

50

10

20

30

40

50

10

20

30

40

50

Vertical orbit at sextupoles [µm]
0.08

LER

0.6
0.06

2.5

∆εy [pm]

2.0

1.5

0.04

∆r2 @ IP [mm]∆r1 @ IP [ × 10−3]

0.4

SLYTLP++SLYTRP++SLYTLP+SLYTRP+-

0.2
0.0

−0.2

1.0

−0.4
−0.6

0

10

20

30

40

Vertical orbit at sextupoles [µm]

50

0.02
0.00
−0.02
−0.04
−0.06

0.5

12/13-14, 2022

0

Vertical orbit at sextupoles [µm]Vertical orbit at sextupoles [µm]

0

10

20

30

40

Vertical orbit at sextupoles [µm]The 26th KEKB Accelerator Review Committee

50

0

10

20

30

40

50

Vertical orbit at sextupoles [µm]30Optics Distortion in IR - Model Calculation - The sign of orbit change is somehow always positive.
- Beam is always squeezed too much and vertical beta function in IR becomes larger.
- It makes stable operation more difficult at high beam current.
<latexit sha1_base64="ukzp1iW21Q7gaEQY2YvcccAPS8k=">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</latexit>

1.4<latexit sha1_base64="4DsrZhEHKW2urBTdwS1cZlTNzXQ=">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</latexit>

βy @ waist [mm]<latexit sha1_base64="2x+4krDpA4Zpp4qOiiJtTMazjGg=">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</latexit>

1.2

Much squeezedy (s) [m]<latexit sha1_base64="3UjYODIk7FQHKERzpvJUWEB8hGM=">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</latexit>

x = +20 µm
x = 0 µm

x=

20 µm

1.0
0.8

Less squeezed

0.6−20 −100
1020
Cosine-like orbit at SLYTLE ∆x [µm]12/13-14, 2022

The 26th KEKB Accelerator Review Committee

31

BPM, Sextupole, Quadrupole and Displacement Sensor- BPM is attached to quadruple magnet by supporting stand.
- Displacement sensor is attached to sextupole magnet.
- The movement of a BPM chamber is measured by the displacement sensor.
- Measured displacement is incorporated in the BPM system for COD measurement.
Displacement sensor
Displacement sensor

Quadrupole magnet

BPM
BPM support
Sextupole magnet

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

Supporting arm

32

Analysis with Orbit at All Sextupole Magnets
06/09/2022

06/19/2022

0.04

SF
SD
SLX
SLY
ALL
TF
Meas.

0.03
0.02
0.01

∆νy

HER

SF
SD
SLX
SLY
ALL
TF

0.00
−0.01
−0.02
−0.03
−0.04
200

400

600

800

1000

Beam current Ib [mA]
12/13-14, 2022

The 26th KEKB Accelerator Review Committee

33

Analysis with Orbit at All Sextupole Magnets
4/26

HER

4/30
SF
SD
SLX
SLY
ALL
Measured
TF

12/13-14, 2022

The 26th KEKB Accelerator Review Committee34

Day to Day Variation

LER- Some amount of vertical tune shift seems to be caused by orbit at SLY.

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

35

Tune Shift Measurement with a Pilot bunch in HERβ*x /β*y = 200 mm/8 mm (no crab waist)

Y. Ohnishi

HER

The bunch current is fixed to be 0.2 mA with changing no. bunches.
10 μm

nb: 783

10 μm

nb: 1565

nb: 978

nb: 393reference
2 μm
2 μm
nb: 393

nb: 783

nb: 978

nb: 1565

reference

10 μm

10 μm

tune shift due to Δνx /I = + 2.2 × 10−5 (1/mA)
resistive wallΔνy /I = − 2.0 × 10−5 (1/mA)
impedance:→ − 1.64 × 10−5 (1/mA)
corrected by orbit deviation

18:50 - 23:10, October 26, 2021

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

364極成分によるチューンシフトの大きさ
Estimation ofで与えられ、Resistive
Wall Tune Shift5250を低減するためのを表す量である。なお、今回検討したダクト断面形
状では、gはhと比較して無視できるほど小さくなる。
面形状の検討- Design study for chamber shapeusing field calculation and a parallel plate model.
平行平板間距離bを変化させながら、MAFIAによりAEqx,yを、式(3)-(5)により単位電流あたりのチュー- To check the 0validityof their
evaluation
method, they calculated
the resistive wall tune shift and compare it toとEqはそれぞれビームqのみからなるとし、E∆νx,y/∆Iをそれぞれ計算することで、A
ンシフト
Eqx,y

らの距離に反比例、比例すると仮定する。このと∆νx,y/∆Iの関係が得られる。任意の断面形状のダク
the measured
tune shift in
KEKB.
軸上とy軸上の電場E
x、Eyはそれぞれ、トにおけるチューンシフトは、MAFIAにより評価し(1) を、この平行平板で得られたAEqx,yと ∆νx,y/∆I
1⁄
φq
E
E
たAEqx,yEq
Theyconcludethat
theirmethodcanreproduce
measuredtune shift
Proceedings of the 5th Annual Meeting of Particle Accelerator Society of Japan
⁄
(2)
1
y
and
the
33rd
Linear
Accelerator
MeetinginJapan(August6-8,
2008,
Higashihiroshima,
Japan)の関係にあてはめることで求める。
E
Eすことができる。ここで、AE0x,y、AEqx,yはそれぞ
observed in KEKB.
-0.206-0.182-0.157-0.133-0.108
３．結果と考察、y軸上における0極成分と4極成分の大きさを
図
2.
KEKB
HER
ダクトの
resistive-wall
ウェイクフィSTUDY ON CROSS-SECTION OF NONCIRCULAR BEAM DUCT TO- The most of beam-pipes in SuperKEKB HER are reused from KEKB.
定数である。各軸上のx、y= 1、5BYmmにおけるREDUCE TUNE SHIFT INDUCEDRESISTIVE-WALL WAKE FIELD
ールドの 4 極成分を表す電場（左）と電位（右）3.1 平行平板
Proceedings of the 5th Annual Meeting of Particle Accelerator Society of Japan
の値と上式を用いてAE0x,y、
AEqx,yKyo
Shibataを算出し、, Yusuke Suetsugu AEqx,y- Therefore,
resistive wall tune shift in SuperKEKB is expected to be similar?
and the 33rd Linear Accelerator Meeting in Japan (August
6-8, 2008, Higashihiroshima, Japan)
High Energy Accelerator Research Organization (KEK)
成分の強さの指標として使用する。
平行平板で求めたAEqx,yと∆νx,y/∆Iの関係を図1に、1-1 Oho, Tsukuba, Ibaraki, 305-0801
3.2 KEKB HER 用レーストラック型ダクト
チューンシフトの計算に用いたパラメーターを表1
Abstract
sistive-wall
チューンシフトの評価法
表 1. チューンシフトの計算パラメーター
図2に、MAFIAで計算したKEKBHER用レースト
Estimatedvalues∑∑にそれぞれ示す。計算に用いた平行平板間距離dは、
The strength of the resistive-wall wake fields of noncircular beam
ducts(parallel plates, racetrack, beam duct with
LER/HER
antechambers) were estimated numerically with MAFIA electrostatic solver (2D). To investigate the relationshipBeam Energy
3.5/8.0 GeV
ラック型ダクト内のEq、及び4極成分による電位 φqbetween the tune shift and the wakefield,the )に対応するチュー
tune shifts in the parallel plates with several vertical separations were記の方法で得られたE
q(A
Eqx,y
40-90
mmである。平行平板間距離が小さくなるほど、Beam Current
1A(6)
calculated analytically. On the basis of the results of the parallel plates,
the tune shifts
in the racetrack duct and thex:45.506/44.515, y:43.545/41.580
ν
フトを求めるために、まず平行平板におけるEを示す。x、y軸上の4極成分の大きさはそれぞれ、
beam ducts with antechambers were estimated from the wake の実部であり、resistive-wallウェイクフィールドの2
fields. The tune shift inqthe racetrack duct was consistentC
3016 mwith the measured value of KEKB electron ring. In the case of極成分によるチューンシフトの大きさを表す量であ
the beamresistive-wallウェイクフィールドの4極成分は大きくduct with antechambers, it was found that theProceedings ofbeam
the 5thchannel
Annual Meetingューンシフトの関係を調べる。平行平板におけ
resistive-wall wake field and tune shift could be reduced by る。一方、hはadopting the elliptically-shaped
insteadofofParticle Accelerator
L Society of Japan
2200 mAEqx = -104.5, AEqy = 109.4であった。これらの値を、
and the 33rd Linear Accelerator Meeting in Japan (August 6-8, 2008, Higashihiroshima, Japan)
circular beam channel.
4)
なり、チューンシフトも大きくなる。また、同じ平n
1584(KEKB), 5018(SuperKEKB)ューンシフトの評価には、次の式を用いる 。∑ ∑(7)
σ
5.4×10 /s (copper)
図1のHERのグラフにあてはめて得られたチューン
Resistive-wallチューンシフトを低減するための
行平板間距離で比較するとHERよりもLER（Low
∆ν
(3)
√2
52
シフトは、∆νx/∆I = 0.028、∆νy/∆I = -0.030となる。
で与えられ、4極成分によるチューンシフトの大きさ
非円形ビームダクト断面形状の検討√
Energy Ring、陽電子蓄積リング）の方がチューンシを表す量である。なお、今回検討したダクト断面形
表 1. チューンシフトの計算パラメーター
gはhと比較して無視できるほど小さくなる。
∑∑状では、
KEKB HERのチューンシフトの実測値は0.03程度な
成分E のみからなるとし、E とE はそれぞれビーム
LER/HER
１．はじめに
平行平板間距離bを変化させながら、MAFIAによ
フトが大きくなるが、これはLERの方がエネルギー
2
(4)
∆ν
√2りA
軸からの距離に反比例、比例すると仮定する。このProceedings of theウェイク
5th Annual Meetingof Particle
Accelerator Society of Japan
Beam Energy
3.5/8.0 GeV
を、式(3)-(5)により単位電流あたりのチュー
非円形ビームダクトでは、resistive-wall√ and the 33rd
、E はそれぞれ、ので、この方法で評価したチューンシフトが妥当でLinear Accelerator Meeting in時、x軸上とy軸上の電場E
Japan (August 6-8, 2008, Higashihiroshima,
Japan)
1A(6) (1) Beam Current
フィールドに4極成分が含まれるため、ビームのベー∆ν /∆Iをそれぞれ計算することで、Aンシフトが小さく、Γが小さくなるためである。
1⁄
タトロン振動数にずれ（チューンシフト）が生じる。
と∆ν /∆Iの関係が得られる。任意の断面形状のダク
x:45.506/44.515, y:43.545/41.580
ν
⁄y
(2)
1
の実部であり、resistive-wallウェイクフィールドの2あることが分かる。
例えばKEK B-factory（KEKB）の場合、電子蓄積リトにおけるチューンシフトは、MAFIAにより評価しC
3016 m(5)
以後、図1のグラフを用いて各断面形状のビーム
極成分によるチューンシフトの大きさを表す量であと表すことができる。ここで、A
、A
はそれぞ
φ
ング（High Energy Ring, HER）ではレーストラック
を、この平行平板で得られたAと ∆ν /∆I
たA
E
L
2200
m
る。一方、hはれ、x、y軸上における0極成分と4極成分の大きさを型の非円形ビームダクトを使用しているが 、蓄積の関係にあてはめることで求める。
n1584(KEKB), 5018(SuperKEKB)
ダクトにおけるチューンシフトの評価を行った。
電流1 Aあたり水平・垂直方向共に0.03程度のチュー
3.3 SuperKEKB 用アンテチェンバー付きビームダク表す定数である。各軸上のx、y= 1、5 mmにおける表 1. チューンシフトの計算パラメーター∑∑(7)はベータトロン振動数、
ω0 =３．結果と考察
で、νx,y。
ンシフトが観測されている∑∑
σ
5.4×10 /s (copper)
Eβ、Ec/Rはビーの値と上式を用いてA
、A
を算出し、
A
LER/HER
図 2. KEKB HER ダクトの resistive-wall ウェイクフィ
次世代の高ルミノシティコライダーであるト
Measured value
を4極成分の強さの指標として使用する。
Beam Energy 0.15
3.5/8.0 GeV
回転周波数、C = 2πRは加速器の周長、Lは非円
ールドの 4 極成分を表す電場（左）と電位（右）
1

x,y

b

17

c

q

0

x

x,y

x,y

q

y

E

E

E

E

Eqx,y

x,y

E0x,y

Eqx,y

1)

50

Eqx,y

Eqx,y
Eqx,y

x,y

q

q

b

-0.206

2)

x

y

E0x,y

Eqx,y

Eqx,y

SuperKEKBでは、その強烈な放射光の対策としてア
3.1 平行平板で与えられ、4極成分によるチューンシフトの大きさ
Beam Current
1A
ンテチェンバー付きビームダクトの採用を予定して

c-0.182-0.157 17-0.133-0.10852(6)2.2 Resistive-wall チューンシフトの評価法
クト部の長さ、Nはビームに含まれる全粒子数、を表す量である。なお、今回検討したダクト断面形
平行平板で求めたAとx:45.506/44.515,∆ν /∆Iの関係を図1に、いるが 、ダクトの断面形状が非円形となるため、
LER
x 3.2 KEKB HER 用レーストラック型ダクト
y:43.545/41.580
ν
今回計算に用いたアンテチェンバー付きビームダの実部であり、resistive-wallウェイクフィールドの2
上記の方法で得られたE (A)に対応するチュー状では、チューンシフトが大きくなり、その対策が必要とな gはhと比較して無視できるほど小さくなる。
チューンシフトの計算に用いたパラメーターを表1
C3016 m古典電子半径、γ
はローレンツ因子、cは光速、極成分によるチューンシフトの大きさを表す量であ0.1
ンシフトを求めるために、まず平行平板におけるE
図2に、MAFIAで計算したKEKB HER用レースト
3)
る可能性がある。そこで我々は、SuperKEKB用のア
平行平板間距離bを変化させながら、MAFIAによにそれぞれ示す。計算に用いた平行平板間距離dは、
The
26th
KEKB
Accelerator
ReviewCommittee
12/13-14,
2022
d=40
L
2200
m
クト
の断面形状の一例を図3に示す。ビームチャンとチューンシフトの関係を調べる。平行平板における。一方、hはンテチェンバー付きビームダクトにおける
3)

x,y

Eqx,y

q

x,y
Eqx,y

q

37

Day to Day Variation

LER- Some amount of vertical tune shift seems to be caused by orbit at SLY.

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

38

Local Orbit Correction at SLYTLE1 and SLYTLE2 Y. Ohnishi
Left side of IP

BPM 1 SD 1-I'

SLYTLE2SLYTLE1SLYTLE2

The local bumps correct the orbit
at SLYTLE1 and SLYTLE2(local chromaticity region;CW sextupoles).

I (mA) in HERSLYTLE1

Δx = 10 μm

temperature (C°)Δx = 10 μm

The horizontal orbit is distorted in the local
chromaticity correction region (SLYTLE1 - SLYTLE2).

SD 2 BPM 2This region can not fit to the gold orbit
when we correct the orbit at SLYs locally.
SLYTLE1SLYTLE2

11

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

39Gap Sensors for the QCS Cryostat
L側

R側

12
30

55

55

30
12

670

580

R2 6

5

43 8
45 5

4.5±4

13

5
R2 6

2 62

3 7 2 .5 9 1 4

1 2 2. 5

R173

R160

R133 .2

443

38
R202 .5

21 3

3

2 9 0. 5

R3
03

R21

R側

2 65

693
Inne r cove r

265

70

92 9 . 5
L側R39 0

77 . 570
3090
6 3 3 .570 0
1 3 3 3. 5

全体GAPセンサー検討
センサーは㈱デジテックスの30mm角形で検討する。

Earthquake

12/13-14, 2022

2017/02/03

Earthquake

The 26th KEKB Accelerator Review Committee

40Gap Sensors for the QCS Cryostat- Is this movement consistent with the HER optics degradation?
- How to utilize the cap sensor in beam orbit and optics tuning?

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

41

Continuous Closed Orbit Correction (CCC)- A closed orbit feedback system named CCC.
- It repeats COD correction with DC steering magnets by ~0.1 Hz.
- It applies COD correction so that difference between measured orbit and areference (golden) orbit is minimized in the root-mean-square (RMS) sense- Residual of the orbit correction isabout 20~30 microns in RMS.
- Optics correction is performed on areference orbit.
- A reference orbit is updated just after
The optics correction.

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

42

Degradation of Closed Orbit
History of residual of closed orbit

Orbit deviation during ~1 week

- Residual of the closed orbit is 20-30 micron.
- Unexpected large orbit changes (Spikes shwon in the right figure)should be investigated.
12/13-14, 2022

The 26th KEKB Accelerator Review Committee

43Some Examples of BPM
Beam position jump by attenuator switching

12/13-14, 2022

Orbit fluctuation at high beam current

The 26th KEKB Accelerator Review Committee

44Some Examples of BPM
Day night effects

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The 26th KEKB Accelerator Review Committee

45

QCS BPMs

Y. Ohnishi

K. Kanazawa, FCC-ee MDI WS, 2018

BPM-bellows tube between IP chamber and QCS

QC1 BPMQC2 BPMBeam pipe with 4 mm thick wall,
and with water cooling channels

QC1 BPM is not fixed at QC1.
There is a bellows between QCS and QC1 BPMs.

2

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

46

BPMs at QCS

Y. Ohnishi

Horizontal crossing angle: 83 mrad

x

x

y

Left Side

BPM
coordinate

SAD
coordinate

Right Side3

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

47

12/13-14, 2022

The 26th KEKB Accelerator Review Committee

48

Design Machine Parameters
Machine Parameters
2017/September/1

LER

HER

unit

E

4.000

7.007

GeV

I

3.6

2.6

A

1.04

mA

2,500

Number of bunches
Bunch Current

1.44
3,016.315

Circumferenceεx/εy3.2(1.9)/8.64(2.8)

4.6(4.4)/12.9(1.5)

Coupling

0.27

0.28

βx*/βy*32/0.27

25/0.30
83

Crossing angle

nm/pm():zero current
includes beam-beam

mm
mrad

αp

3.20x10-4

4.55x10-4σδ

7.92(7.53)x10-4

6.37(6.30)x10-4

Vc

9.4

15.0

MV

σz

6(4.7)

5(4.9)

mm():zero current

νs-0.0245-0.0280

νx/νy44.53/46.57

45.53/43.57

U0

1.76

2.43

MeV

τx,y/τs45.7/22.8

58.0/29.0

msec

ξx/ξy

0.0028/0.0881

0.0012/0.0807

Luminosity

12/13-14, 2022m

8x1035The 26th KEKB Accelerator Review Committee():zero current

cm-2s-1

49