1. J.W. Flanagan @ ASEPS 2010.3.24 KEKB Upgrade Plan: SuperKEKB J.W. Flanagan ASEPS 2010.3.24

2. J.W. Flanagan @ ASEPS 2010.3.24 Contents 1.Introduction – SuperKEKB Luminosity goal 2.Strategy: Nano-Beam Scheme – Much smaller  y * –Larger crossing angle at IP & low emittance – Same  y as KEKB –Higher beam currents than KEKB 3.What we need –Lattice design for the Nano-beam scheme –IR design –Hardware 4.Schedule 5.Summary

3. J.W. Flanagan @ ASEPS 2010.3.24 1.Introduction SuperKEKB Luminosity goal

4. J.W. Flanagan @ ASEPS 2010.3.24 Target: 8 × 10 35 cm -2 s -1 = 40 x World Record (KEKB) 4

5. J.W. Flanagan @ ASEPS 2010.3.24 2.Strategy Nano-beam scheme – Much smaller  y * –Larger crossing angle at IP & low emittance – Same  y as KEKB –Higher beam currents than KEKB

6. J.W. Flanagan @ ASEPS 2010.3.24 The scheme proposed by P. Raimondi and SuperB Group. Squeeze  y * as small as possible: 0.27/0.41 mm. Assume beam-beam parameter = 0.09 which has been already achieved at KEKB. Change beam energies 3.5 / 8 -> 4 /7 GeV to achieve longer Touschek lifetime and mitigate the effect of intra- beam scattering in LER. Nano-beam Scheme H. Koiso 6

7. J.W. Flanagan @ ASEPS 2010.3.24 Stored current: 1.7 / 1.4 A (e + / e - KEKB) 3.6 / 2.6 A (SuperKEKB) Beam-beam parameter: 0.09 (KEKB) 0.09 (SuperKEKB) Vertical β at the IP : 6.5/5.9 mm (KEKB) 0.27/0.41 mm (SuperKEKB) Lorentz factor Classical elec. radius Beam size ratio Geometrical correction factors due to crossing angle and hour-glass effect 1(  y ) x 20(1/  y * ) x 2(I) = 40 0.21 ×10 35 cm -2 s -1 (KEKB) 8×10 35 cm -2 s -1 (SuperKEKB) 1(  y ) x 20(1/  y * ) x 2(I) = 40 0.21 ×10 35 cm -2 s -1 (KEKB) 8×10 35 cm -2 s -1 (SuperKEKB) Three key factors for a factor of ~40 gain

8. J.W. Flanagan @ ASEPS 2010.3.24 e- 2.6 A e+ 3.6 A x 40 Gain in Luminosity SuperKEKB Colliding bunches Damping ring Low emittance gun Positron source New beam pipe & bellows Belle II New IR Replace long TRISTAN dipoles with shorter ones (HER) TiN-coated beam pipe with antechambers Redesign the HER arcs to squeeze the emittance Add / modify RF systems for higher beam current New positron target / capture section New superconducting /permanent final focusing quads near the IP Low emittance electrons to inject Low emittance positrons to inject 8

9. J.W. Flanagan @ ASEPS 2010.3.24 KEKB Design KEKB Achieved : with crab SuperKEKB Energy (GeV) (LER/HER)3.5/8.0 4.0/7.0 Crossing angle (mrad)220 (crab)83 β y * (mm)10/105.9/5.90.27/0.41 ε x (nm)18/1818/243.2/2.4 σ y (μm)1.90.940.059 ξyξy 0.0520.129/0.0900.09/0.09 σ z (mm)4~ 66/5 I beam (A)2.6/1.11.64/1.193.6/2.62 Number of bunches500015842503 Luminosity (10 34 cm -2 s -1 ) 12.1180 SuperKEKB Parameters as of Feb.15, 2010

10. J.W. Flanagan @ ASEPS 2010.3.24 3.What we need Lattice design for the Nano-Beam Scheme IR design Hardware

11. J.W. Flanagan @ ASEPS 2010.3.24 Lattice design for the Nano-Neam Scheme Low β y * IR optics design, Local Chromaticity Corrector (LCC) Low emittance LER: Longer bending magnets to lower average energy of SR emitted in high dispersion regions (bends), and shorten wiggler period by factor of 2. HER: Increase number of arc cells to lower dispersion in bends Arc bends shortened and increased in number. Wide dynamic aperture IR optics design QC1,2 magnets closer to IP Separated final quadrupole magnets Beam energy was changed reduce intra-beam scattering and increase Touschek lifetime for LER LER: 3.5 to 4.0 GeV, HER: 8.0 to 7.0 GeV Design target (Touschek) lifetime is > 600 sec (min. 400 sec)

12. J.W. Flanagan @ ASEPS 2010.3.24 A. Morita KEKB Review Feb.2010 Lattice design for the Nano-Neam Scheme Angle of 41.5 mrad between HER orbit and Belle To save vertical emittance increase by anti-solenoid fringe fields

13. J.W. Flanagan @ ASEPS 2010.3.24 Lattice 13 A. Morita KEKB Review Feb.2010

14. J.W. Flanagan @ ASEPS 2010.3.24 3.What we need Lattice design for the nano-beam scheme IR design Hardware

15. J.W. Flanagan @ ASEPS 2010.3.24 IR design M. Tawada KEKB Review Feb.2010 QC1 magnets closer to IP Superconducting & permanent magnets Boundary between accelerator & detector is same as at present 83 mrad Full crossing Permanent magnets: Cryostats can be made smaller Vacuum pump can be located near IP Superconducting magnets: Leakage fields of SC magnets canceled by correction windings on the other beam pipe Warm bore

16. J.W. Flanagan @ ASEPS 2010.3.24 3.What we need Lattice design for the Nano-Beam Scheme IR design Hardware

17. J.W. Flanagan @ ASEPS 2010.3.24 Injectors & Damping ring The injected beam should have very low emittance because of poor dynamic aperture of the main rings.

18. J.W. Flanagan @ ASEPS 2010.3.24 (1)Damping Ring for LER Lattice Design almost completed. M. Kikuchi KEKB Review Feb.2010 Injection (2)Low emittance RF gun for HER S. Ohsawa, T. Sugimura KEKB Review Feb.2010

19. J.W. Flanagan @ ASEPS 2010.3.24 Vacuum Straight ductBPMFeed through for NEG Bellows chamber RF-shield (gate valve) Gate valve Y. Suetsugu Basic R&D on components has almost finished. Optimization of design should be required considering the cost. Aluminum beam ducts can be used for LER.

20. J.W. Flanagan @ ASEPS 2010.3.24 Beam ducts with ante-chambers – Low beam impedance Pump ports and SR masks locate in an antechamber. – Fit to the existing (reused) magnets. – TiN coating to reduce secondary electron yield Effectiveness demonstrated at PEP-II NEG strip Y. Suetsugu KEKB Review Feb.2010 Vacuum: Electron cloud suppression Clearing electrodes and grooved structures developed for electron cloud suppression  Collaboration with Cornell, SLAC, LBL Stainless steel Tungsten ( t 0.1) Al 2 O 3 ( t 0.2) An insertion for test with a thin electrode 400 mm x 40 mm B by L. Wang et al. RtRt d (Roundness) (Depth) Monitor R47 Groove Y. Suetsugu, H. Fukuma, M. Pivi and L. Wang, NIM-PR-A, 598 (2008) 372 Y. Suetsugu, H. Fukuma, M. Pivi and L. Wang, NIM-PR-A, 604 (2009) 449

21. J.W. Flanagan @ ASEPS 2010.3.24 RF system 2 ARES cavties/klystron to 1/klystron for more power Low total RF voltage is obtained while each cavity is operated at a high voltage. Higher-Order Mode dampers

22. J.W. Flanagan @ ASEPS 2010.3.24 Main dipole magnets need to be replaced for both HER and LER rings. – LER dipoles become longer (Leff 0.89 m ⇒ 3.99 m) : 104 needed – HER dipoles become shorter (Leff 5.91 m ⇒ 3.8 m) : 144 needed 112 wiggler magnets with shorter pole length (half pole)& 56 single pole wiggler needed. More dipole, quadrupole and sextupole magnets are needed in HER since number of cells increased (~30 % more magnets). ⇒ Magnet & power supply design & production & field measurements (from 500 to 1000 magnets need to be measured) Most of the magnets will be relocated to new positions. ⇒ Realignment is necessary. Magnet and power supplies

23. J.W. Flanagan @ ASEPS 2010.3.24 Beam Instrumentation Beam Position Monitors – For high currents, and fast (~kHz) orbit vibration feedback Bunch-by-bunch Feedback – Next generation system being developed in collaboration with SLAC, INFN, others Beam size monitors for low-emittance beams – Synchrotron Light Monitors – X-ray Monitors (collaboration including Cornell) Collision monitor – Beamstrahlung Monitor Gated measurements 23

24. J.W. Flanagan @ ASEPS 2010.3.24 Schedule

25. J.W. Flanagan @ ASEPS 2010.3.24 Presuppositions We present fastest possible schedule with following presuppositions: – Not a small part of budget allocated to KEK in JFY2010 be assigned to KEKB upgrade by the KEK Executive Board. – Positive decision be made by the committee for large- scale projects in MEXT by this summer. – Budget for the Damping Ring tunnel and buildings be allocated in JFY2011 by the Japanese Government. – Full approval of the overall project, SuperKEKB, be made in JFY2011 by the Japanese Government. K. Akai 25

26. J.W. Flanagan @ ASEPS 2010.3.24 FY2009FY2010FY2011FY2012FY2013FY2014 Beam pipes (LER_arc) Beam pipes (HER_arc) Beam pipes (LER_wiggler) Magnets & Power supplies Tunnel clear Beam monitors and Control IR hardware RF reinforcement Fabrication TiN coating Install Fabrication TiN coating Install Remove magnets and beam pipes Base plates Fabrication Install Design / Fabrication Field measurement Install Cabling / Check Alignment 2nd? R&D / Fabrication QCS R&D Layout change / Add stations / Cavity improvements QCS fabrication MR commissioning Beam operation Design Test Condit ioning Install & test Install & test SuperKEKB Main Ring schedule K. Akai Feb.2010

27. J.W. Flanagan @ ASEPS 2010.3.24 Install Beam pipes B&Q mag. design/fabricate Install Magnets & Power supplies FY2009FY2010FY2011FY2012FY2013FY2014 align. Tunnel construction RF System MR construction Beam operation Injector upgrade and DR construction schedule Other magnets Tunnel & building Design Building construction Base plan cavity design cavity fabrication cavity install HP&LLRF install Install Monitors, Control Fabrication MR commissioning RF-gun & laser system e+ new matching & L-band acc. R&D Construction Design study Commisioning at test stand e- beam commisioning move to A1 e+ beam commissioning Damping Ring Linac Main Ring HP test Power supplies Field measurement DR commissioning A1 gallery extension A1 gallery extension 27 K. Akai Feb.2010

28. J.W. Flanagan @ ASEPS 2010.3.24 Summary

29. J.W. Flanagan @ ASEPS 2010.3.24 Summary Nano-Beam Design: – Lattice: solutions exist, preserving the present tunnel. Optimization of dynamic aperture is ongoing. – IR: large crossing angle, independent quadrupoles for both beams. – Electron cloud mitigation has been studied at KEKB. – RF system will be added and modified to store beam currents twice those of present KEKB. – Design of e+ damping ring has been done. – Low-emittance electron gun will be installed in linac. Construction Schedule: – Target schedule: SuperKEKB commissioning starts at the beginning of JFY2014. 29 H. Koiso KEKB Review Feb.2010

30. J.W. Flanagan @ ASEPS 2010.3.24 Spares

31. J.W. Flanagan @ ASEPS 2010.3.24 Facilities Storage and staging areas needed for magnet and vacuum components. Need increased cooling water for klystrons and magnets: – 24 klystrons for ARES cavities, 8 klystrons for SCC – Magnet cooling water needs double (4 plants -> 8) Electricity: KEKB/KEK total Electricity Consumption: June-09 (Design option)KEKB:MWΔMWKEK:MWΔMW Present(Average) 4564 Nano Beam: June-09 70.724.39632 Upgrade: Feb.-09 94.849.812056 Super: ‘07-July 102.657.612864 Recent Design(Feb.-10): Add 2 ARES units--> +(3~4)MW M. Ono KEKB Review Feb.2010