1. SuperKEKB Project Status Mika Masuzawa (KEK)

2. Contents 1.Introduction – SuperKEKB Luminosity goal – What was presented at XI SuperB WS @LNF Dec.2009 by Ohmi 2.Strategy for 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.Summary (& budget) –Where we are –The comments from 15 th KEKB review last month –Budgets

3. 1.Introduction SuperKEKB Luminosity goal What was presented at XI SuperB WS at LNF Dec.2009 by Ohmi

4. Luminosity goal 8 x 10 35 cm -2 s -1

5. Slides @XI SuperB General Meeting LNF, December 2009 by K.Ohmi (KEK) We worked hard and hard KEKB exceeded 21/nb/s with crab crossing but the beam-beam parameter is still 0.09 We worked hard and hard KEKB exceeded 21/nb/s with crab crossing but the beam-beam parameter is still 0.09 High current & high beam-beam scheme High current & high beam-beam scheme Low emmittance “Nano-beam” scheme was announced. Low emmittance “Nano-beam” scheme was announced.

6. 2.Strategy Nano-beam scheme – Much smaller  y * –Larger crossing angle at IP & low emittance – Same  y as KEKB –Higher beam currents than KEKB

7. The scheme proposed by P. Raimondi and SuperB Group.  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 KEKB Review Feb.2010

8. 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

9. Low emittance positrons to inject e- 2.6 A e+ 3.6 A Low emittance gun Nano-Beam SuperKEKB Redesign the HER arcs to reduce the emittance. New Superconducting / permanent final focusing quads near the IP Colliding bunches Low emittance electrons to inject New positron target / capture section Replace long dipoles with shorter ones (HER). TiN coated beam pipe with antechambers Add / modify rf systems for higher currents. ~40 times gain in luminosity

10. 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 Parameters presented at KEKB MAC Review Feb.15-17, 2010 SuperKEKB Parameters as of Feb.15, 2010

11. 3.What we need Lattice design for the Nano-Beam Scheme IR design Hardware

12. Lattice design for the Nano-Neam Scheme Low β y * IR optics design, Local Chromaticity Corrector (LCC) Low emittance HER - Increase number of arc cells LER - Longer bending magnets & change the wiggler layout Wide dynamic aperture IR optics design QC1,2 magnets closer to IP Separated final quadrupole magnets Beam energy was changed due to short 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)

13. A. Morita KEKB Review Feb.2010 Lattice design for the Nano-Neam Scheme

14. A. Morita KEKB Review Feb.2010 Lattice design for the Nano-Neam Scheme

15. A. Morita KEKB Review Feb.2010 Lattice design for the Nano-Neam Scheme

16. A. Morita KEKB Review Feb.2010

20. LER HER SuperKEKB arc section Longer dipole Cells change in HER Grey: SuperKEKB Black : present KEKB Low emittance HER - Increase number of arc cells LER - Longer bending magnets & change the wiggler layout

21. SuperKEKB IR Left Grey: SuperKEKB Black : present KEKB LER HER Low β y *, smal beam size IR optics design Local chromaticity corrector in both LER & HER

22. LER HER Grey: SuperKEKB Black : present KEKB SuperKEKB IR Right Low β y *, smal beam size IR optics design Local chromaticity corrector in both LER & HER

23. Low emittance HER - Increase number of arc cells LER - Longer bending magnets & change the wiggler layout SuperKEKB wiggler section

24. 3.What we need Lattice design for the nano-beam scheme IR design Hardware

25. 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

26. IR design Superconducting magnets Leakage fields of SC magnets canceled by correction windings on the other beam pipe Warm bore Permanent magnets (pros) Cryostats can be made small Assembly of vacuum chamber can be simple Vacuum pump can be located near IP Permanent magnets (cons) R&D work Temperature dependence Tunability (an additional magnet is needed when changing the energy) M. Tawada KEKB Review Feb.2010

27. Belle rotation Pros. – We don’t need to rotate HER orbit – Extra space for PXD/SVD cables and tubes will be available – EM force will be reduced if the radius of anti-solenoid would be smaller Cons. – Expensive (3 oku yen for belle rotation) – Need to modify the concrete bases and shields – Belle people worry about the damaging CsI calorimeter No conclusion yet M. Tawada KEKB Review Feb.2010

28. 3.What we need Lattice design for the Nano-Beam Scheme IR design Hardware

29. Injectors & Damping ring The injected beam should have very low emittance because of poor dynamic aperture of the main rings. We have decided to construct a damping ring for the LER and a low emittance RF-gun for the HER.

30. (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

31. 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.

32. Beam ducts with ante-chambers – Low beam impedance Pump ports and SR masks locate in an antechamber. – Fit to the existing (reused) magnets. Material – LER: Aluminum alloy is now available. – LER wiggler sections: Copper is required. – HER: Copper is required. NEG strip Pump (NEG) is installed into one of the ante-chamber (inside of the ring) –Distributed pump system for effective pumping. S ~ 80 l/s/m. –Inserted from end flanges. Y. Suetsugu KEKB Review Feb.2010 Vacuum: Electron cloud suppression

33. Clearing electrode has been said to be very effective to reduce EC in magnetic field. – Impedance and heating of electrode have been serious problems for intense e + beam. ⇒ Very thin electrode structure was developed. – 0.2 mm Al 2 O 3 and 0.1 mm tungsten (W) electrode formed by a thermal spray method.  1 kV is OK. – Good heat transfer and low beam impedance – Flat connection between feed-through and electrode Y. Suetsugu, H. Fukuma, M. Pivi and L. Wang, NIM-PR-A, 598 (2008) 372 Stainless steel Tungsten ( t 0.1) Al 2 O 3 ( t 0.2) To feed-through An insertion for test with a thin electrode Feed-through 400 mm x 40 mm Connection to feed through Vacuum: Electron cloud suppression Y. Suetsugu KEKB Review Feb.2010

34. Grooved surfaces: geometrically reduce SEY. – The properties were studied in a wiggler magnet using the same experimental setup to that of the clearing electrode. – B = 0.78 T Parameters of grooves – Material: Cu, Al-alloy, SS –  : 20~30 , R t :0.1~0.2 mm – d: 2.5~5 mm B by L. Wang et al. RtRt d (Roundness) (Depth) Monitor R47 Y. Suetsugu, H. Fukuma, M. Pivi and L. Wang, NIM-PR-A, 604 (2009) 449 Groove Y. Suetsugu KEKB Review Feb.2010 Vacuum: Electron cloud suppression For countermeasures against electron cloud in a dipole field, clearing electrodes and grooved surface are found to be very effective.

35. 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

36. 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 Review committee Report The tightest part of the schedule is the removal and reinstallation of the tunnel components including the magnets, supports, and vacuum beam ducts. The planning for the schedule for these activities should be taken to the next level of sophistication to resolve potential conflicts with resources. Interferences with other laboratory resource needs should be determined and taken into account.

37. Photos are from the KEKB construction days, shown reversely. Magnet removal Magnet lifted up Magnet on the air pallet Magnet taken away from the beam line to an access shaft. (There are 4 access shafts in the tunnel) Move it up to 1 st floor of the access shaft by crane (one by one) to a storage area (where?)

38. Removing the old (orange) base plates, repairing the floor,surveying, marking the new beam line & installation of the new base plates. Arc section

39. Summary Where we are

40. 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. 40 H. Koiso KEKB Review Feb.2010

41. Summary Some from the Review Committee (Feb.15~17, 2010) Reports

42. More work needed in: *Further optimization of chromaticity correction, optimization of the local chromatic sections, and ways to control chromatic coupling effects. *Tolerances on field errors and alignments particular to the small x-y coupling. *IR optics (small beta*, large beta_max, correction scheme, solenoid orientation angle, tapered solenoids). IR design in still in flux. Crab waist implementation (although not necessarily on day 1; the option must be kept in lattice design). *Momentum aperture (optimize for Touschek lifetime). *Dynamic aperture (required for injection). *Energy variation (how do solenoids and permanent magnets vary when beam energy is varied?). *Polarized beams? (Make sure this is NOT needed. Otherwise, this will drive the design in a strong way, so it has to be determined early – cannot retrofit.)

43. Review Committee Reports The overall R&D and construction schedules for SuperKEKB were shown, and the details discussed. The plan is for a 3.5 year construction time starting mid-year in JFY2010. The overall schedule looks well thought out and complete. It appears to have a good chance of being able to be carried out if the funding is provided as proposed. There is some uncertainty, however, because the funding profile for each year is not really known. KEK management should ensure that the resources needed for the Nano-Beam studies are made available (staffing, computing). The most important issue is the established shortfall in staff during the construction period (~30 people) and in the operating era. In this context, the Committee recommends exploring collaborations with universities, industry and other laboratories world-wide.

44. Budgets

45. Budget allocated so far – Besides the annual operation budget, new budget has been allocated: FY2009 Supplementary Budget of 25.5 Oku-Yen (1 Oku-Yen = ~1.1 M$) was allocated to KEKB for development of low-emittance beam device. – This budget is being used for fabricating a part of ante-chambers for the LER wiggler section, reinforcement of RF system, and R&D for key components such as IR magnets, positron source, etc. FY2010 a budget of 5.83 Oku-Yen was allocated for KEKB reinforcement. This single year budget is the first year of three-year plan for the Damping Ring construction in total of 25 Oku-Yen. – An announce was made abroad by the DG of KEK as "The Japanese Government has announced KEK's budget for JFY2010, in which preliminary approval was given to the KEKB upgrade program, and a budget was allocated to partially start construction. This does not yet constitute full approval of the overall project, but can be interpreted as a provisional decision by the Government in these difficult times of drastic change in the Japanese Government." K. Akai KEKB Review Feb.2010

46. Committee for large-scale projects A committee that discusses large-scale academic projects was established last year under Science and Technology, Academic Council in MEXT. – The committee discusses ways to promote large-scale academic projects in Japan. – Roadmap in each research field is being discussed in the Science Council of Japan, which will be submitted to the committee. The committee will discuss and settle on the roadmap. The committee is to decide which projects to be pushed forward in coming years. – The decision will be made by this summer, hopefully. K. Akai KEKB Review Feb.2010

47. 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 “ (Ministry of Education, Culture, Sports, Science and Technology,) 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 KEKB Review Feb.2010

48. 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 KEKB Review Feb.2010

49. Cost estimation ComponentsCost (Oku-Yen) Remarks Linac upgrade and Damping Ring31e+ matching and L-band acc., RF-gun and laser system, Damping Ring components Vacuum System135beam pipes (ante-chambers, electrodes, etc), pumps and other vacuum components for 3km x 2 rings Magnet System93magnets,power supplies, cables IR upgrade20QCS and other hardware RF System25add 9 RF stations, improve cavities (coupler, HOM damper) Beam monitor and control32BPM, SRM, feedback, control system, etc. Belle upgrade14.7 Total350.7 1 (Oku-Yen) = 1.1 M USD = 0.8 M EUR (as of 12 Feb, 2010) Cost for DR tunnel construction is not included in the list. Also cost for buildings and facilities for Linac, DR and MR is not included. These costs are about 30 Oku-Yen in total. This list is what went to MEXT last year. According to recent estimation, cost for some components increases, but some others decrease. 49 K. Akai KEKB Review Feb.2010

50. Shutdown for Upgrade 1.2 /ab/month (8 x10 35 /cm^2/s) 0.9 /ab/month (6 x10 35 /cm^2/s) 0.6 /ab/month (4 x10 35 /cm^2/s) Learning Curve Physics Program Evaluation 50 /ab J. Flanagan Shifted by 0.5 year Target schedule: SuperKEKB commissioning starts at the beginning of JFY2014.

52. 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

53. Design strategy a) Development of a new button electrode for higher currents e) Use of displacement sensors to measure the movement of BPM due to thermal deformation of a chamber. b) Development of a new narrow-band detection module for 509 MHz detection for precise measurements. Lower detection frequency to get below cut-off frequency due to antechambers (900-990 MHz) c) Development of a medium-band detection module for orbit stabilizing feedback and gated turn by turn orbit measurement for optics measurement. d) Development of a special detection module for collision feedback. Button with small (6 mm) diameter, pin type inner conductor Beam Instrumentation: BPMs LER chamber Electrode H. Fukuma ◊Feedback needs to have a gain in the region < 100Hz. Required rep. rate of the measurement of ~ several kHz (e.g. 5 kHz).

54. Bunch by bunch feedback system Longitudinal feedback system will be required in LER. Noise in transverse feedback system should be minimized to reduce the blowup of the beam size during collision. Vacuum components such as kickers, power cables, feedthroughs and BPM electrodes should withstand large beam current. H. Fukuma Beam Instrumentation: Feedback iGp digital signal processing system ◊Tested successfully for the transverse and longitudinal system at KEKB. ◊Developed under US-Japan collaboration (KEK-SLAC). Firmware is supplied by DimTel. ◊Adaptable to almost any harmonic number. ◊Operation at 509MHz is possible for KEKB. ◊8tap FIR(KEKB) to 32 Tap FIR (DAFNE) are available. ◊Down sampling function for Longitudinal feedback. ◊Bunch-selected FB ON/OFF and excitation. ◊Transient-domain analysis for study of instability. ◊Capable to monitor a feedback signal without disturbing feedback. Next generation system with a digital filter working at ~1.3 GHz using new FPGA, and ADC and DAC with higher resolution is under development.