SuperKEKB Ring status
Mika Masuzawa, Makoto Tobiyama
KEK Accelerator Laboratory
BPAC Reivew 5/Feb/2024

1

Major Vacuum Works during LS1

2

LER vertical impedance（βy*=1 mm,Before LS1）

Vertical collimator

σz=6.0 mm

Tapered beam-pipe with BPM in final
focusing magnet (QC1)

Vertical dipolar kick factor: 𝑘 ,Vertical tune shift: Δ𝜈
TMCI threshold: 𝐼

𝑑𝑠𝑊 , 𝑠, σ 𝜆 𝑠∑ 𝛽,𝑘 , ,⁄/∑,Beam-pipe around interaction point(IP chamber), Transverse Mode Coupling Instability (TMCI) Major impedance sources: Vertical collimator, QCS beampipe, IP chamber

3

LER ‒ Veritcal（βy*=1 mm, Before LS1）
 Bunch current dependent vertical tune shift: agreed the simulation results using
impedance models (GdfidL, CST)
 Simulated threshold of TMCI ~1.75 mA/bunch Design bunch current：1.44 mA/bunch
vertical tune shift4

HER ‒ Vertical（βy*=1 mm）

Vertical collimator

σz=5.0 mm

Flange (104x50)

Tapered beam-pipe with BPM in final
focusing magnet (QC1) Major impedance sources: Vertical collimator,Vacuum flanges (helicoflex), Bellows, QCS beampipe
5

HER ‒ Vertical（βy*=1 mm）
 Bunch current dependent tune shift: agreed the simulation results
 TMCIの閾値： ~3.5 mA/bunch
 設計バンチ電流：1.04 mA/bunch
vertical tune shift

6

LER ‒ Nonlinear collimator[A. Natochii][example] collimator setting and βyky for βy*=1 mm optics.

Collimatorβy [m]

Half-aperture [mm] a)βyky [×1015, V/C]

D06V167.35

2.9

9.77

D06V2

20.57

2.6

3.64

D03V1

16.96

8.0

0.50

D02V1

11.89

1.1

7.72

D05V14.05 b)

50.28a)b)

Averaged value of top and bottom half-aperture at 2021-12-22
Optics file: sler_1800_80_1.sad
Bunch current threshold of TMCI𝐼4𝜋𝜈 𝐸/𝑒𝑇 ∑ 𝛽 ,𝑘 ,7

2021c physics run

D06V1

βy*=1 mm
βx*=80 mm

LS1後D06V1
D05V1
Photo of the non-linear collimator section (2023-05-26)

D05V1

SNAP.1(not installed yet)• Σβyky will reduce from 3.97e4 downto 3.18e4 V/pC
• Threshold of TMCI is estimated to increase more than
2.mA/bunch

8Collimators
D01

D01H4 D01H5 D02H4 D02H3 D02

IRe-

D12V4
D12D12H4
D12V3
D12H3
D12H2
D12V2
D12H1
D12V1

TSUKUBA

D03
D03H1

SuperKEKB Main Ring

D05V1

: Vertical Collimator, KEKB HER(50x104) typeD10D09V4
D09H4
D09V3
D09H3
D09H2
D09H1
D09V2
D09V1

WIGGLERWIGGLER

OHO

NIKKO

SCSC

WIGGLER: Horizontal Collimator, KEKB HER(50x104) type

ARES

D04

LER

HER

ARES

D11e+

D02H1
D02V1 D02H2

D01V1
D01H3

: Horizontal Collimator, SuperKEKB LER(f90x220) type

D05

: Vertical Collimator, SuperKEKB LER(f90x220) type
: Horizontal Collimator, SuperKEKB LER(f90) type
: Horizontal Collimator, SuperKEKB HER(f80x220) type
: Vertical Collimator, SuperKEKB HER(f80x220) type
D06V2

FUJI

D09e-D08

D06V1
D06H4
D06H3e+

D06

D079

Status of LER collimator
Name

Type

D06H3
D06H4
D03H1
D02H1
D02H2
D02H3
D02H4

SuperKEKBSuperKEKBSuperKEKBSuperKEKBSuperKEKBSuperKEKBSuperKEKB

Tip Material(): longitudinal length in mm
Cu coated C (160)
Ta (10)W (10)W (10)W (10)W (10)W (10)

D06V1
D06V2
D05V1
D02V1SuperKEKB
SuperKEKBSuperKEKBSuperKEKB

Cu coated Ti (10)hybrid (3)Cu coated Ta (4)Cu coated Ta (10)Tip Condition

Remarks

healthyhealthyhealthyhealthyhealthyhealthyhealthyspoiler against inj. kickers’ accidental firings
absorber against inj. kickers’ accidental firings

healthyhealthyhealthyhealthy10Status of HER collimator
Name

Type

Tip Material(): longitudinal length in mm

Tip Condition

Drive Mechanism

D09H1
D09H2
D09H3
D09H4
D12H1
D12H2
D12H3
D12H4
D01H3
D01H4
D01H5

KEKB
KEKB
KEKB
KEKB
KEKBKEKBKEKBKEKBSuperKEKBSuperKEKBSuperKEKB

Cu coated Ti (40)
Cu coated Ti (40)
Cu coated Ti (40)
Cu coated Ti (40)Ti (40)Cu coated Ti (40)Ti (40)Cu coated Ti (40)W (10)W (10)W (10)

damageddamageddamageddamagedhealthydamagedhealthyhealthyhealthyhealthyhealthy

-

D09V1
D09V2
D09V3
D09V4
D12V1
D12V2
D12V3
D12V4
D01V1

KEKB
KEKB
KEKB
KEKB
KEKB
KEKB
KEKB
KEKB
SuperKEKB

Cu coated Ti (40)
Cu coated Ti (40)
Cu coated Ti (40)
Cu coated Ti (40)
Cu coated Ti (40)
Cu coated Ti (40)
Cu coated Ti (40)
Cu coated Ti (40)
Cu coated Ta (10)healthyhealthyhealthyhealthydamageddamagedhealthyhealthyhealthy

Remarks

upgraded

upgraded
upgraded
upgraded11

Spare jaws
Tip Material(): longitudinal length in mm
HER vertical: Cu coated Ta (10)HER vertical: Cu coated Ta (10)HER vertical: Cu coated Ti (40)
HER vertical: Cu coated Ti (40)LER vertical: Cu coated Ta (10）LER vertical: Cu coated Ta (10）LER vertical: hybrid (3）LER vertical: hybrid (3）LER vertical: Cu coated Ta (10)LER vertical: Cu coated Ta (10)LER horizontal: Ta (10）Collimator to be installed(assumed)
D01V1
D01V1
D09V1-V4, D12V1-V4
D09V1-V4, D12V1-V4
D02V1
D02V1
D05V1, D06V1-V2
D05V1, D06V1-V2
D02V1, D05V1, D06V1-V2
D02V1, D05V1, D06V1-V2
D06H4

Remarks
Plan to deliver in this fiscal year.
Plan to deliver in this fiscal year.

Plan to deliver in this fiscal year.
Plan to deliver in this fiscal year.

12Sudden beam loss Replaces the damaged collimator heads
 Cu coated heads in vertical plane (Large vertical gap to D6V1 due to NLC) Bunch by bunch beam position monitor using• Existing BOR• iGp12 Block RAM: phase space monitoring• Simple BOR using oscilloscope (D7 and D5)

 More loss monitors around collimators
 Acoustic monitors at collimators and QCS beam pipe13Non-Linear Collimator

14Non Linear Collimator

15

Power supplies

16Temporally using old power supplies

17

2024

January27(Sat)28(Sun)29(Mon)February30(Tue)31(Wed)1(Thu)

2(Fri)HER vacuum scrubbing HER vacuum scrubbing HER vacuum scrubbing
HER vacuum scrubbing 200 mA
250 mA
250 mA
100 mALER vacuum scrubbing LER vacuum scrubbing LER vacuum scrubbing
100 mA
200 mA
250 mA

C: OwlHER βy* = 81.0 mm
Find COD
HER BCMLER βy* = 48.6 mm(without D05V1)
Find COD
HER BCM

LER/HER TBT BPM
study

LER βy* = 48.6 mm(with D05V1)
LER optics correction
D05V1 study

DA measurement

A: DayHER BxB FB tuning

LER BxB FB tuning

HER injection tuning
HER kicker jump
HER septum tuning

D05V1 study
LER impedance meas.

DA measurement

HER BxB FB tuning

LER BxB FB tuning

LER injection tuning
LER kicker jump
LER septum tuning

LER/HER QuadBPM

acoustic sensor (SBL)

HER BPM gain mapping LER BPM gain mapping
HER optics correction LER optics correction
LER/HER QuadBPM
HER injection tuning
LER injection tuning

LER/HER QuadBPM

acoustic sensor (SBL)

B: Evening18

2024February3(Sat)

C: Owl4(Sun)

5(Mon)

6(Tue)

7(Wed)

8(Thu)

9(Fri)HER vacuum scrubbing HER vacuum scrubbing HER vacuum scrubbing HER vacuum scrubbing HER vacuum scrubbing HER vacuum scrubbing HER vacuum scrubbing
300 mA
300 mA
350 mA
350 mA
400 mA
400 mA450 mALER vacuum scrubbing LER vacuum scrubbing LER vacuum scrubbing LER vacuum scrubbing LER vacuum scrubbing LER vacuum scrubbing LER vacuum scrubbing
300 mA
300 mA
350 mA
350 mA
400 mA
400 mA450 mALER NEG activation

LER βy* = 48.6 → 8mm
LER βy* = 8 → 3 mm
LER βy* = 3 → 2 mm
LER βy* = 2 → 1 mm

HER βy* = 81 → 8 mm
HER βy* = 8 → 3 mm collision tuning
HER βy* = 3 → 2 mm find collision backet
HER βy* = 2 → 1 mm

LER NEG activation

LER optics correction

HER optics correction

collision tuning

HER optics correction
LER optics correction

LER BxB FB tuning

HER BxB FB tuning

LER TBT BPM study

collimator tuning

LER injection tuning
LER collimator tuning
LER impedance meas.

HER injection tuning
HER collimator tuning HER TBT BPM study
HER impedance meas.

collimator tuning

LER D05V1 study

A: DayLER D05V1 study

B: Evening

192024February
10(Sat)

C: Owl11(Sun)12(Mon)13(Tue)14(Wed)15(Thu)16(Fri)

HER vacuum scrubbing HER vacuum scrubbing HER vacuum scrubbing HER vacuum scrubbing HER vacuum scrubbing HER vacuum scrubbing HER vacuum scrubbing
500 mA
500 mA
500 mA
550 mA
600 mA
600 mA
600 mALER vacuum scrubbing LER vacuum scrubbing LER vacuum scrubbing LER vacuum scrubbing LER vacuum scrubbing LER vacuum scrubbing LER vacuum scrubbing
500 mA
500 mA
500 mA
550 mA
600 mA
600 mA
600 mAHER sextupole study

LER sextupole study

LER rotating sextupole

HER sextupole study

LER sextupole study

LER rotating sextupole

HER TBT BPM study

LER TBT BPM study

HER TBT BPM study

LER TBT BPM study

A: DayB: Evening

20

2024

February
17(Sat)

C: Owl18(Sun)19(Mon)20(Tue)21(Wed)22(Thu)23(Fri)

HER vacuum scrubbing HER vacuum scrubbing HER vacuum scrubbing HER vacuum scrubbing
600 mA
600 mA
600 mA496 mALER vacuum scrubbing LER vacuum scrubbing LER vacuum scrubbing LER vacuum scrubbing
600 mA
600 mA
600 mA
620 mAtuning for physics run

maintenance (regular)

A: Daytuning for physics run

B: Evening

21

Current, Luminosity

22

23

Base and Target Plan
2024-ab-lumiplan

400Integrated Luminosity(1 mm)

350

Total(1mm Target)
Total(1mm Base)

Base plan:
1mm 40% eff : 150fb-1300

Target plan:
1mm 60% eff : 360 fb-1250
200
1501005002024/1/29

2024/3/25

2024/5/20
Day
24

Ring status 29/Jan• Start injection to HER, struggled to find the BT-end orbit and final septumsettings.
• Confirmed 6-7 turns of revolution without RF, starting RF on operation.

 30/Jan• 0:01 confirmed storing beam after many trial (tune, injection phase, injection
kicker settings)• HER FB timing adjustments, HER optics tuning.
• Start LER injection tuning 31/Jan• LER beam storage• LER FB timing adjustments, LER optics tuning.

 5/Feb• NEG activation (day shift)25Beam Dose (1/29 ∼ 2/5 8:00)
HER beam dose (21 Ah)

HER current (∼400 mA)
LER current (∼330 mA)

Date & Time

Beam Dose [Ah]Beam Current [A]LER beam dose (18 Ah)

Beam Dose (1/29 ∼ 2/5 8:00)
2/13?

LER current(∼330 mA)

Beam Dose [Ah]Beam Current [A]HER current(∼400 mA)

HER beam dose (21 Ah)
LER beam dose (18 Ah)

Date & Time

Vacuum Scrubbing (1/29 ∼ 2/5 8:00)

LER

Whole ring

Arc sections

Beam Dose [Ah]p/I [Pa/mA]

p/I [Pa/mA]

HER

Whole ring
Arc sections

Beam Dose [Ah]29

QCS-R re-install Re-tried on 23/Oct/2023 with• Modified RVC gear
• Modified VXD cable support• The QCS supports was carefully advanced by Tanaka-san.

 RVC worked very smoothly‒ no vacuum leak found.

30

Recovery of IR concrete shields• IR concreate shield recovery works（2024/1/9-1/12）• 門型シールド前進• 足場設置• 取り外したシールドを設置、固定（１）• Installment of new shields• 取り外したシールドを設置、固定（２）• 門型シールドを最終位置まで前進• 門型シールド固定• 足場撤去SKEKBルミノシティ問題対策会
議2023/11/**31

IR shield works• IR concreate shield recovery works（2024/1/9-1/12）• 門型シールド前進• 足場設置• 取り外したシールドを設置、固定（１）• Installment of new sheilds• 取り外したシールドを設置、固定（２）• 門型シールドを最終位置まで前進• 門型シールド固定• 足場撤去SKEKBルミノシティ問題対策会
議2023/11/**32

IR shield works• IR concreate shields recovery works（2024/1/9-1/12）• 門型シールド前進• 足場設置• 取り外したシールドを設置、固定（１）• 新シールドを設置• 取り外したシールドを設置、固定（２）• 門型シールドを最終位置まで前進• 門型シールド固定• 足場撤去SKEKBルミノシティ問題対策会
議2023/11/**33

Oho Radiation shield
廃棄されたIR旧コンクリートシールド• Re-use of concreate shield used at IR• NLC下流側の大穂実験棟の門型シールド上に設置（2023年11月）• もう1台は廃棄• New radiation controlled-area: Oho experimental hall, D5,
Pump/PS building after 1/15
この空間を埋める必要あり

D05V1(NLC)SKEKBルミノシティ問題対策会
議2023/11/**34

Oho radiation shield• Re-use of the concreate shields used at IR• NLC下流側の大穂実験棟の門型シールド上に設置（2023年11月）• もう1台は廃棄

IR旧コンクリートシールドを再利用

SKEKBルミノシティ問題対策会
議2023/11/**35