March 26, 2024

SuperKEKB ITF
Y. Ohnishi
The 27th KEKB Accelerator Review Committee

International Task Force (ITF) for SuperKEKB
Find Realistic Path to 1035 cm-2s-1 after LS1
Find Ideas to 6x1035 cm-2s-1 after LS2 with Major Modifications
ITF 2023 Activities from January 2023 for 1 year
Chairperson: Y. Ohnishi

B-Factory
Promotion OfficeAccelerator
Review Committee

N. SaitoA
T. KosekiA

75 Researchers joined(39 Researchers from Foreign Institutes about 52 %)F. ZimmermannB

Collective Effects

FCC-ee, CEPC, EIC, Super-Tau-Charm(Beam-Beam, Impedance)

Beam Tuning

IR UpgradeSudden Beam Loss

Beam Injection

G. MitsukaA
M. MiglioratiC, N. WangD,
D. ZhouA, T. IshibashiA

Y. OhnishiA
H. SugimotoA, R. ThomasB

D. ZhouA
X. WangA

H. IkedaA
H. NakayamaA

N. IidaA
T. YoshimotoA

Organized under the B-Factory Promotion Office at KEK.

A) KEK, B) CERN, C) UNIROME1, D) IHEPKey Points to Be Discussed
Investigation of Factors Inhibiting Accelerator Performance Improvement
Understanding of SBL, Fireball Hypothesis, Collimators, Impedance Budget
Maintaining Beam Orbit and Beam Optics Corrected at Low Current (Resolving Time Fluctuation
and Beam Current Dependence)Beam-Beam Issues (Beam Blowup)
Understanding and Addressing Injection Issues

Analysis of Data from Operation up to Summer 2022
Strategies for Post-LS1 Operation
Shortest Path to 1035 cm-2s-1, Formulation of Machine Parameters, Safe Ways to Increase Beam
Current, Squeezing β*yPlanning and Execution of Machine Studies

Planning of Modifications for Post-LS2
Large Modification of IR3

Activities of International Task Force
Beam Injection:
Mitigation of CSR: "Canceling Optics" at Beam Transport Line Is One of the Candidates (FERMI, Italy).
Machine Learning Is Essential to Improve Injection Performance. APS Upgrade Is Presented.
Sudden Beam Loss: Understanding of Physical Mechanism Is On-going. Plan of Simulating Beam-CollimatorInteraction Is under Consideration (CERN)
Beam Tuning:
New Method to Correct Local Coupling at IP Used at LHC, Feasibility of TBT BPMs, Stability of Cooling Water System.
Collective Effects (Beam-Beam):Strong-Strong Beam-Beam Simulations with Full Lattice: Ongoing Efforts of KEK, IHEP, and CERN
Collective Effects (Impedance):"PyHEADTAIL" Estimates Transverse-Mode-Coupling Instability (TMCI) Threshold Is ~1.8 mA/bunch. Introducing a
Non-Linear Collimator System Will Raise the Threshold to ~2.1 mA/bunch.
IR Upgrade:
Understanding Challenges in IR Optics for Upgrade among International Teams
Synergy with European Teams under the Support of EAJADE (F. Zimmermann)

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ITF Future5Future Prospects
Developmental Reorganization. “ITF” to “International Working Group” (Tentative)
Chairpersons of the Activity: 3rd, 4th, and 5th Division Head
Compiles the Activities of International Cooperation Related to SuperKEKB.
Beam Tuning and Operation
Sudden Beam Loss (SBL)
Beam-Beam Interaction and Collective Effects
Beam Instrumentation
Future Upgrade
Each Working Group Is the Main Activity.
On-Site Workshop (In Person and Remote)Activities and Results will Be Reported in the ARC.
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Meeting Slides and Materials

INDICO: https://kds.kek.jp/category/2242/"Mattermost": Information Sharing Business Chat Tool (https://skb-itf-chat.kek.jp)

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Appendix

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Beam Tuning Subgroup9

Beam Tuning Meeting
February 14 2023: Beam Tuning (1)Issues to Be Discussed (Y. Ohnishi)
Brief Introduction of SuperKEKB Lattice (Y. Ohnishi)

March 14 2023: Beam Tuning (2)SuperKEKB Optics Measurements and Corrections (H. Sugimoto)
IR Coupling Correction in the LHC with Waist Shift (F. Soubelet)
Status of Turn-By-Turn Measurements in SuperKEKB (J. Keintzel)

April 19 2023: Beam Tuning (3)Vertical Fast Collision Feedback at SuperKEKB (H. Fukuma)
IP Orbit Control System and Operation (R. Ueki)
Continuous Closed Orbit Correction (CCC) and Orbit Stability (Y. Ohnishi)

September 19 2023: Beam Tuning (4)Beam Orbit Issues (H. Sugimoto)
Synchrotron Radiation at IR (M. Kikuchi)
IR Orbit (Y. Ohnishi)
Plan of Commissioning in 2023c and 2024a (Y. Ohnishi)
10Beam Injection Subgroup

11Beam Injection Meeting
March 2 2023: Beam Injection (1)Injection Status and Issues (N. Iida)
Injection and Lifetime (Y. Funakoshi)
Injector Linac (M. Satoh)

April 4 2023: Beam Injection (2)Incoherent and Coherent Synchrotron Radiation in the SuperKEKB Electron Beam Transport (Y. Yoshimoto)Measurement of Possible Long-Range Wake Field Effects of Primary E-Beam with 10nC/Bunch (T. Natsui)
Jitter Emittance in the Linac (N. Iida)

June 14 2023: Beam Injection (3)Lessons Learned From the FERMI DEL Zone (S. D. Mitri)
Theoretical Explanation of CSREffect on Emittance Growth Suppression with Vertical Bump Orbit (T. Mori)

September 27 2023: Beam Injection (4)ML-Based Optimization at APS and Plans for APS-Upgrade (N. Kuklev)
Machine Learning-Assisted Beam Tuning at Linac and SuperKEKB (G. Mitsuka)
2023-2024 Linac, BT, SuperKEKB Operation Plan (N. Iida)
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Sudden Beam Loss Subgroup13

Sudden Beam Loss Meeting

April 7 2023: SBL (1)Electron Cloud at Collimator (Y. Suetsugu)
Simulation of Electron Cloud Buildup at Collimators by the Modified CLOUDLAND (H. Fukuma)
Acoustic Wave Observation for Collimators (T. Abe)

June 30 2023: SBL (2)BOR Timing Analysis for Sudden Beam Loss Aborts (M. Aversano)
Simulation of Electron Cloud Buildup at Collimators by the Modified CLOUDLAND --Ofset Beam-- (H. Fukuma)
The 1st Result of Beam Simulation for the Fireball SBL Hypothesis (T. Abe)

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Collective Effects Subgroup15

Collective Effects Meeting
Feb. 6 2023: Collective Effects (1)Opening Remarks and Issues to Be Discussed (Y. Ohnishi)
Scope of Work in 2023 (G. Mitsuka)

Feb. 7 2023: Collective Effects: Beam-Beam (2)SCTR-CUDA (K. Ohmi)
Computation of Complex Error Function, Comparison of Accuracy and Speed (D. Shatilov)

March 24 2023: Collective Effects (3)FCC-ee Collective Effects (M. Migliorati)
Impedance Modeling and Single-Bunch Collective Instability Simulation for the SuperKEKB Main Ring (T. Ishibashi)

June 1 2023: Collective Effects: Beam-Beam (4)Beam-Beam Mode Coupling (K. Ohmi)
Beam-Beam Simulation for Post-LS1 Target Luminosity 1035 (D. Zhou)

July 7 2023: Collective Effects (5)IHEP and CEPC Activities on Collective Effects (N. Wang)
Summary of Bunch Length Measurements at KEK (G. Mitsuka)
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IR Upgrade Subgroup17

IR Upgrade Meeting
Feb. 17 2023: IR Upgrade (1)Opening Remarks (Y. Ohnishi)
Overview of SuperKEKB IR (K. Shibata)
Discussion on Tasks/Goal of ITF-IR Subgroup (D. Zhou)

March 7 2023: IR Upgrade (2)A Proposal for the Upgrade of the Final Focus System of SuperKEKB (M. Koratzinos)
Final Focus Beam Dynamics Studies (P. Raimondi)

March 28 2023: IR Upgrade (3)Current QCS Magnet System (Y. Arimoto)Constraints on Investigations of SuperKEKB IR-Upgrade Under the ITF-IR Framework (D. Zhou)

April 18 2023: IR Upgrade (4)Beam-Induced Background Status and Expectation in Belle II (A. Natochii)
Dynamic Aperture for Crab Waist in LER (Y. Ohnishi)

May 23 2023: IR Upgrade (5)Comments on Detector Constraints on IR Design (F. Forti)
Tentative Parameter Table for Post-LS2 SuperKEKB and Strategy for ITF-IR Workgroup (D. Zhou)
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