LS1 Status
The 26th KEKB Accelerator Review Committee
14th Dec. 2022
Kyo Shibata

Inter-University Research Institute Corporation High Energy Accelerator Research Organization (KEK)
大学共同利用機関法人 高エネルギー加速器研究機構 (KEK)Contents• Introduction• Challenges and countermeasures• LS1 schedule• IR status (Tsukuba straight section)• NLC status (Oho straight section)• Others• Summary

14th Dec. 2022

The 26th KEKB Accelerator Review Committee

2Challenges as a luminosity frontier machine

Y. Suetsugu (2021.09.02)
The 25th KEKB Accelerator Review Committee+ 6) Low injection efficiency especially in HER.
14th Dec. 2022

The 26th KEKB Accelerator Review Committee

3

Countermeasures against challenges
Y. Suetsugu (2021.09.02)
The 25th KEKB Accelerator Review Committee

During LS1
Done before LS1
Under consideration(It was found that it is not easy.)

Under consideration
During LS1

Done before LS1
Under consideration
During LS1
During LS1 (Partially)
During LS1 (Partially)
During LS1 (Partially)

14th Dec. 2022

The 26th KEKB Accelerator Review Committee

4Schedule
Ceiling aseismic reinforcing work

• LS1 : 15 months from July 2022 to September 2023

• 2022b run stopped earlier than planned due to high electricity costs (22nd June), but LS1 majorworks began on 11th July as scheduled.
• Beam operation will restart from October 2023.

• Major works during LS1 other than accelerator upgrade:• Belle II maintenance and reinforcement••

Replacement of PXD and TOP MCP-PMTs, new IP beam pipes, and so on.
IR works are required, including QCS extraction & reinstallation, disassembly & reinstallation of magnets,
beam pipes, radiation shields, etc.

• Aseismic reinforcing work of the ceiling of the laboratory building (Oho Lab. & Fuji Lab.)••It takes about 5 months and it can be done only during long shutdown.
During this work, we can not use ceiling crane required for NLC construction at Oho Lab.!!

S. Nakamura

LS1 schedule

We are here now!!

2022

JFY202245

67820239102022b run
Ceiling aseismic reinforcing work

1112

1

4

14th Dec. 2022

56

78

3

Long Shutdown 1 (Accelerator upgrade)
Belle II maintenance & reinforcement2023

JFY202322024
910Long Shutdown 1 (Accelerator upgrade)
Belle IImaintenance & reinforcement
The 26th KEKB Accelerator Review Committee

112023c run

1212

32024a run

5IR (Tsukuba straight section) #1
QCS movable platform

Belle II• Major work items in accelerator tunnel:• Disassembly and reinstallation of concreteradiation shields• Belle II maintenance & reinforcement work
• Disassembly and reinstallation of magnets, beam
pipes for QCS work
• QCS extraction & reinstallation• QCSR cryostat leak test
• QCS cryostat modification

IRQCS cryostat

Concrete radiation shield

We are here now!!

2022
56JFY2022

7820239Concrete shield disassembly

2022b run

1011121

JFY2023

5Belle II work

678

QCS reinstallation
Magnet & beam pipe disassembly
Belle IImaintenance & reinforcement

14th Dec. 2022

23

QCS cryostat
modification

QCS extraction
QCSR cryostat leak test

Belle II maintenance & reinforcement

2023
4

PositronbeamElectronbeam

IR (Tsukuba straight section)
4

Tsukuba lab.

2024
91011

12

1

2

3

Concrete shield reinstallation

Belle II work

The 26th KEKB Accelerator Review Committee

2023c run

2024a run6IR (Tsukuba straight section) #2IR• Concrete radiation shields disassembly (already done)

Tsukuba lab.

• Concrete radiation shields were temporarily removed for IR works.
• They will be reinstalled in mid September 2023.
• To suppress background noise of Belle II, 2 concrete shields will be replaced with new ones.
• New shields will be delivered in February 2023.

Electronbeam

PositronbeamThis shield will be replaced with new one.
This space will befilled with concrete.

Concrete shield disassembly work
14th Dec. 2022

New concrete shield
The 26th KEKB Accelerator Review Committee

H. Yamaoka7

IR (Tsukuba straight section) #3• Disassembly of magnets & beam pipes for QCS extraction (already done)

IRTsukuba lab.

• To make space for QCS extraction, magnets and beam pipes were removed.
• For QCS cryostat work, some magnets and beam pipes on QCS movable platform
were also removed.
Magnets & beam pipes should be disassembled

QCS extraction

QCS movable platform

Electronbeam

Positronbeam

QCS extraction

QCS movable platform
14th Dec. 2022

Disassembly work
The 26th KEKB Accelerator Review Committee8

IR (Tsukuba straight section) #4IR• QCS extraction (already done)

Tsukuba lab.

• RVC disassembly was performed by Belle II and SuperKEKB for the first time.
• RVC : Remote Vacuum Connection between IP bellows chambers and QCS beam pipes• DESY, who is RVC developer and has been in charge of RVC disassembly so far, also joined thework online. Thank you very much for the kind work manual and cooperation!!
• Although camera for monitoring the RVC movement did not work, disassembly work went well.

Electronbeam

Positronbeam• QCS extraction of both sides was completed successfully in one day!!
RVC lock flange of IP bellows chamber
K. Gadow (DESY)

RVC mechanism
14th Dec. 2022

Remotemanipulation
wheel
The 26th KEKB Accelerator Review Committee

QCS extraction
9IR (Tsukuba straight section) #5
IR• QCSR cryostat leak test (already done)

Tsukuba lab.

• Pressure in QCSR cryostat has been higher than that in QCSL cryostat.

• Residual gas analysis showed that vacuum leak has occurred in QCSR cryostat.
• However, vacuum leak test before LS1 did not detect any vacuum leak.

• Thorough vacuum leak test was performed after QCS extraction.

Electronbeam• At last, the location of the vacuum leak was identified!!
• Vacuum leak will be stopped during LS1.

Positronbeam• Inside observation of beam pipes• Inside of IP bellows, QCS beam pipes were observed by fiberscope.

• Fiberscope observations showed that RF fingers of IP bellows and QCS beam
pipes are discolored but healthy.

QC1RP

Vacuum leak test of QCSR cryostat
14th Dec. 2022

QC1LE
The 26th KEKB Accelerator Review Committee

IP bellows chamber with BPM
10IR (Tsukuba straight section) #4IR• Future works

Tsukuba lab.

• QCS cryostat modification• To reduce Belle II background noise, the material at the tip of QCS cryostat will be changed fromW to SUS.
• QCSR front cap replacement• QCSL front plate replacement• To make more space for Belle II cables, the tip of QCSR cryostat will be thinner.

Electronbeam

Positronbeam• QCSR cryostat modification including front cap replacement• QCS cryostats will be disassembled for these works.
BPM feedthroughBPM feedthrough• It is necessary to shift QCS beam pipes in longitudinal direction.
QCS beam pipe

QCS beam pipe

Y. ArimotoTo access QCS pipes & BPMs,
this part should be disassembled.

To access QCS pipes & BPMs,
these windows should be open.

T. OkiY. Arimoto
QCSR front plate
replacement

QCSL
14th Dec. 2022

QCSR front cap
replacement

QCSR

The 26th KEKB Accelerator Review Committee11IR (Tsukuba straight section) #5
IR• Remaining works in accelerator tunnel:••••

Belle II maintenance & reinforcement (∼ June 2023)
QCS cryostat modification (March 2023)
QCS reinstallation (July ∼ August 2023)
Concrete shield reinstallation (Sep. 2023)• It is required to coordinate schedule with Belle II work and NLC construction.

IR (Tsukuba straight section)

We are here now!!

2022
56JFY2022

7820239Concrete shield disassembly

2022b run

1011

12

1

JFY2023

5

Belle II work

67

8

QCS reinstallation
Magnet & beam pipe disassembly
Belle IImaintenance & reinforcement

14th Dec. 2022

2

3

QCS cryostat
modification

QCS extraction
QCSR cryostat leak test

Belle II maintenance & reinforcement

2023
4

PositronbeamElectronbeam• All works can be completed by the end of September 2023.

4Tsukuba lab.

2024
91011121

2

3

Concrete shield reinstallation

Belle II work

The 26th KEKB Accelerator Review Committee

2023c run

2024a run12

Oho straight section #1
Concrete radiation shield• Major work items in accelerator tunnel:

D05 wiggler section

Tsukuba (Belle II)
Oho lab.

D04
D05

Positronbeam

S. Nakamura

Oho straight section (D05)

We are here now!!

2022
456

JFY202278202391011

RF cavity
inspection
Crane not available
Ceiling aseismic reinforcing work

Concreteshield removal

2022b run121JFY2023

5678

3

RF cavity replacement2024
9101112123

NLC construction
New radiation shield
Concrete shieldinstallation
reinstallation

14th Dec. 2022

2NLC construction

2023
4

Ohostraight section• Disassembly and reinstallation ofconcrete radiation shields• NLC construction (LER)• RF cavity replacement (LER)• Ceiling aseismic reinforcing work
• Installation of new radiation shields

The 26th KEKB Accelerator Review Committee

2023c run

2024a run13

Oho straight section #2• Concrete radiation shields disassembly (already done)

Tsukuba (Belle II)• Concrete shields were placed outside Oho laboratory building.

• They will be reinstalled in late August 2023.

Ohostraight section• Concrete radiation shields (6/12) were temporarily removed for NLC construction.
D04
D05

Positronbeam

Oho Lab.

Disassembled concrete shieldConcrete shield disassembly work
14th Dec. 2022

The 26th KEKB Accelerator Review Committee

14

Oho straight section #3
Tsukuba (Belle II)• Wiggler magnets and beam pipe removal (already done)••••

Double pole magnet (3 ton) : 20
Single pole magnet (2 ton) : 10Half pole magnet (1.5 ton) : 20Cables : 3 ton

D04
D05

• Removed beam pipe for wiggler magnet : 10 beam pipes• Disassembly procedure
•
••
•
•

Removal of wiggler magnet cables
Upper parts of wiggler magnets disassembly
Beam pipes removal
Upper parts of wiggler magnets reassembly
Wiggler magnets removal

Positronbeam

10 times

S. Nakamura

Wiggler beam pipe removal work
14th Dec. 2022

The 26th KEKB Accelerator Review Committee

Ohostraight section• Removed wiggler magnet and cable : 50 magnets and their cables

15

Oho straight section #4
Magnet power supply room (ground level)• Future works for NLC construction

D04
D05

• Future works for radiation shielding enhancement

Cable pit 1• Production & installation of new Pb radiation shields• Production & installation of additional concrete shields• Reinstallation of concrete shields

Positronbeam

Cable pit 2
S. Nakamura

Additional concrete shields

collimator∼50 mmNew Pb radiation shield
Y. Sakaki
14th Dec. 2022

concrete shields

The 26th KEKB Accelerator Review Committee

Ohostraight section• Collimator relocation from D03V1• Q magnet relocation• Skew sextuple magnets installation• Beam pipe installation• Installation of new power supplies• Magnet cabling works

Tsukuba (Belle II)

Cable pit (KEKB tunnel)
16Oho straight section #5
Tsukuba (Belle 2)• Remaining works in accelerator tunnel:

Oho lab.

D04
D05• All works can be completed by the end of September 2023.

Positronbeam• Schedule is very tight.

Oho straight section (D05)

We are here now!!

2022
45

62022b run

JFY2022782023910

11

RF cavity
inspection
Crane not available
Ceiling aseismic reinforcing work

Concreteshield removal

121JFY2023

56783

RF cavity replacement2024
910111212

3

NLC construction
New radiation shield
Concrete shieldinstallation
reinstallation

14th Dec. 2022

2NLC construction

2023
4

Oho
straight section• NLC construction (∼ Sept. 2023)• RF cavity replacement (Jan. ∼ Feb. 2023)• New radiation shield installation (June ∼ Sept. 2023)• Concrete shield reinstallation (August 2023)

The 26th KEKB Accelerator Review Committee

2023c run

2024a run17

Others major works (excluding Linac)
T. Ishibashi• Robust collimator head (LER)• As countermeasure against kicker-pulser misfiring and resulting
destruction of collimator•MRCarbon collimator head•••

Replacement with carbon head of horizontal collimator D06H3 and relocationfrom D06H1 to D06H4
Carbon head production : ∼ March 2023
Head replacement : Spring ∼ Summer 2023
Collimator relocation : Spring ∼ Summer 2023

• New beam pipes with wider aperture at HER injection point• For injection efficiency improvement••••

Y. Suetsugu

Beam pipe atHER injection point

New beam pipes with wider aperture & New BPM for precise measurement ofinjected beam
Beam pipe production : ∼ March 2023
Beam pipe replacement : Spring ∼ Summer 2023
Septum baking : ∼ Summer 2023?

• RF cavity modification and replacement (LER)• For stable operation with larger beam current

DR••

Modification : Input coupler replacement, cooling power enhancement, coaxial
line modification, etc. (done)
Cavity replacement (D05A) : January ∼ February 2023

• Vacuum seal replacement at RF section (DR)• For pressure reduction•Replacement from elastomer gasket to metal gasket for dummy pipes (done)• DR Extraction kicker power supply modification and repair (DR)• For stable operation

DR Ext. kicker
14th Dec. 2022•

DR RF section

Modification : December 2022 ∼ August 2023

• And so on…

The 26th KEKB Accelerator Review Committee

18

Summary• Many upgrade works are done during Long Shutdown 1 (LS1).

• LS1 started in July 2022 and will end in September 2023. (15 months)• “Belle II maintenance & reinforcement” and “Aseismic reinforcing works of theceiling of the laboratory building” are also done during LS1.

• Status of “IR works” & “NLC construction” were reported in detail.

• Both works are progressing as planned so far.
• It is possible to complete all works by the end of September and resume beam
operation from October 2023.
• It takes much longer time for some materials and devices to be delivered, so
more careful coordination of LS1 schedule until the end of LS1 is required.

14th Dec. 2022

The 26th KEKB Accelerator Review Committee

19Fin.

Thank you for your attention.

Inter-University Research Institute Corporation High Energy Accelerator Research Organization (KEK)
大学共同利用機関法人 高エネルギー加速器研究機構 (KEK)