LS2

Mika Masuzawa
26th ARC, Dec.14, 2022

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What we accomplished

26th ARC, Dec.14, 2022

2

What we accomplished

Peak luminosity and Beam currents(up to June 22, 2022)

KEKB

SuperKEKB
26th ARC, Dec.14, 2022

By Y. Suetsugu

3What we accomplished

Integrated luminosity and Power consumption(up to Mar. 2022)

26th ARC, Dec.14, 2022

By Y. Suetsugu

4SuperKEKB (”nano-beam” scheme) is “eco”
economical and ecological
But our goal is luminosity

26th ARC, Dec.14, 2022

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“Next Generation B-factories” @IPAC10LS1LS2~3 ab-1

If we had kept running KEKB we would have accumulated ~3 ab-1 over 10 years
26th ARC, Dec.14, 2022

6

Y. Suetsugu (Feb. 2022)

We are closer to the base plan

We need toincrease Ib
squeeze by*
26th ARC, Dec.14, 2022

achieve higher Lsp at higher I7b

Y. Ohnishi (yesterdayʼs talk)H. Sugimoto (This morningʼs talk)
There seems to be something more to be understood about our IR.

We should understandour IR first → Modification
26th ARC, Dec.14, 2022

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We should understand our IR first
but a flow chart on IR modification
Issues such as
QCS Dynamic aperture
Lifetime
QCS Physical aperture
Backgroundetc
Why Lsp drops at higher Ib?

Optics

Ideas
Hardware requirements
Specifications
Boundary between QCS and Belle II

Belle II
modification may
becomenecessary

Estimate of construction time and $/€/¥
Hardware design
Hardware manufacture
R&D
Installation
Commissioning

Hardware test

26th ARC, Dec.14, 2022

9Presented by Y. Suetsugu at the ITF kickoff meeting in July 2021
Among options “option3” seems to be doable.

We decided to revisit IR upgrade plan(s).
26th ARC, Dec.14, 2022

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IR/QCS upgrade
Progress“ Option 3ʼ ”

2022/12/14

11Revisit QC1P modification
1. Increase QC1P aperture (vertical) from 13mm to (18mm) 20.7 mm→ Larger physical aperture
2. Fabricate new anti-solenoid coil and move it closer to the IP→ less x-y coupling might be achieved
3. Cover QC1P by magnetic material→ magnetic coupling reduction may be achieved

Working with the Optics G

2022/12/14

121. Increase QC1P aperture (vertical) from 13mm to (18mm) 20.7 mm

2022/12/14

UWG meeting Oct. 13, 202213

2. Fabricate new anti-solenoid coil and move it closer to the IP
Design concept (A. Morita)• Beam entering QC1P parallel to QC1P axis
• Zero coupling/zero chromaticity between IP andQC1P←Cancellation between IP and QC1P
• Minimum vertical emittancePresent magnet position wrt to orbit

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QCS upgrade
Adding special superconducting solenoid here:• Very thin SC solenoid (thickness=2mm)• Cryostat thickness=20mm

Seek a solution
to lower the field

Possibility: RVC locates at the IP chamber side,
BPM is in the side of 、BPM locates at the
QCS side.
L=553 mm:Solenoid field=-1.5 T

2022/12/6

L=187 mm:Solenoid field=4.4
T

Solenoid field=0 T

From N. Ohuchi

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QCS upgrade

From N. Ohuchi

Bmin & Bmax reasonable→Optics G will do some quantitative evaluation with a simple model.
If does not work with a simple model, no point spending more time on hardware design.
2022/12/6

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Something needs to be done
IR modification, for example..
Issues such as
QCS Dynamic aperture
Lifetime
QCS Physical aperture
Backgroundetc
Why Lsp drops at higher Ib?

OpticsIdeasHardware requirements
Specifications
Boundary between QCS and Belle II

Belle II
modification maybecome
necessary

Estimate of construction time and $/€/¥
Hardware design
Hardware manufacture
R&D
Installation
Commissioning

Hardware test

26th ARC, Dec.14, 2022

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There are other ideas for upgrades other than IR(New electron BT line, e- ECS, modification of vacuum chamber, and so on)
And some can be done during the summer/winter shutdown periods.
We do not know if/when LS2 takes place.
But we should keep working on the ideas.

And before anything else, we must achieve 1x1035cm-2s-1
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26th ARC, Dec.14, 2022

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