1. Report from the GDE Barry Barish ACFA Workshop EXCO, Daegu, Korea 11-July-05

2. ACFA Workshop - Barish 2 The Energy Frontier

3. 11-July-05 ACFA Workshop - Barish 3 The Third ACFA Statement on International Linear Collider issued on Nov. 3, 2004 at the 9th Plenary ACFA In August 2004, ICFA has decided on superconducting technology for the future linear collider (LC), by endorsing the resolution of the international technology recommendation panel (ITRP) created by ILCSC under ICFA. The ITRP report emphasizes the importance of world-wide unified approach as a single team to design the international linear collider (ILC). ACFA has discussed various issues relating to ILC in the plenary meeting of ACFA at VECC, Kolkata in India on 2-3 Nov. 2004, and ACFA came to the following conclusions  ACFA welcomes the truly international nature of the decision on technology for the ILC. This sets the stage for international collaboration in the design efforts for the ILC.  ACFA reaffirms that the ILC, the next major high-energy physics project, should be realized by world-wide efforts. In such International collaboration ACFA and scientists in ACFA countries should play crucial and leading roles.  ACFA reconfirms the importance of hosting ILC in Asia, which will make high energy physics and accelerator science truly global.

4. 11-July-05 ACFA Workshop - Barish 4 The Third ACFA Statement on International Linear Collider  ACFA urges the Japanese Government to fully support the efforts of KEK and Japanese scientists to host the ILC in Japan.  ACFA reconfirms that KEK is the best suited institute in Asia for hosting the Central Team of GDI.  ACFA urges KEK to establish the Asian Regional Center for R&D in GDI and encourages other Asian countries to actively participate in GDI.  With ILC entering this important phase, ACFA urges Governments of Asian countries to support participation of their scientists in GDI. ACFA feels that Asia has wide expertise in accelerator technology which can be directed to develop SCRF technology required for the ILC, and large trained manpower which can make major contributions to the ILC. Because ILC will pose major scientific and technical challenges, there will be several technological fallouts. ACFA therefore feels that by participating in the ILC not only the scientific community of the participating country but also its industry will benefit.

5. 11-July-05 ACFA Workshop - Barish 5 The Community then Self-Organized Nov 13-15, 2004

6. 11-July-05 ACFA Workshop - Barish 6 The First ILC Meeting at KEK There were 220 participants divided among 6 working groups Working Group 1: Overall Design Working Group 2: Main Linac Working Group 3: Injector, including damping rings Working Group 4: Beam Delivery Systems, including collimator, final focus, etc. Working Group 5: Cavity design: higher gradients,.. Working Group 6: Strategic communication Each working group had three convenors, one from each region

7. The Global Design Effort Formal organization begun at LCWS 05 at Stanford in March 2005 when I became director of the GDE Technically Driven Schedule

8. 11-July-05 ACFA Workshop - Barish 8 GDE – Near Term Plan Staff the GDE –Administrative, Communications, Web staff –Regional Directors (one per region) –Engineering/Costing Engineer (one per region) –Civil Engineer (one per region) –Key Experts for the GDE design staff from the world community –Fill in missing skills (later) Total staff size about 20 FTE (2005-2006)

9. 11-July-05 ACFA Workshop - Barish 9 GDE – Near Term Plan Organize the ILC effort globally –First Step --- Appoint Regional Directors within the GDE who will serve as single points of contact for each region to coordinate the program in that region. (Gerry Dugan (North America), Fumihiko Takasaki (Asia), offered to Brian Foster (Europe)) –Make Website, coordinate meetings, coordinate R&D programs, etc R&D Program –Coordinate worldwide R & D efforts, in order to demonstrate and improve the performance, reduce the costs, attain the required reliability, etc. (Proposal Driven to GDE)

10. 11-July-05 ACFA Workshop - Barish 10 GDE – Near Term Plan Schedule Begin to define Configuration (Aug 05) Baseline Configuration Document by end of 2005 ----------------------------------------------------------------------- Put Baseline under Configuration Control (Jan 06) Develop Reference Design Report by end of 2006 Three volumes -- 1) Reference Design Report; 2) Shorter glossy version for non-experts and policy makers ; 3) Detector Concept Report

11. 11-July-05 ACFA Workshop - Barish 11 Starting Point for the GDE Superconducting RF Main Linac

12. 11-July-05 ACFA Workshop - Barish 12 Some Key Near-Term Design Choices Accelerating Gradient Positron Production mechanism Design of Damping ring Site-specific considerations: One or two tunnels? Shallow or deep?, etc Total cost will be a key determining factor in our ability to get the ILC built. Therefore cost optimization of all systems is of primary importance

13. 11-July-05 ACFA Workshop - Barish 13 Towards the ILC Baseline Design

14. 11-July-05 ACFA Workshop - Barish 14 Parameters for the ILC E cm adjustable from 200 – 500 GeV Luminosity  ∫ Ldt = 500 fb -1 in 4 years Ability to scan between 200 and 500 GeV Energy stability and precision below 0.1% Electron polarization of at least 80% The machine must be upgradeable to 1 TeV

15. 11-July-05 ACFA Workshop - Barish 15 rf bands: L-band (TESLA)1.3 GHz  = 3.7 cm S-band (SLAC linac) 2.856 GHz1.7 cm C-band (JLC-C)5.7 GHz0.95 cm X-band (NLC/GLC)11.4 GHz0.42 cm (CLIC)25-30 GHz0.2 cm Accelerating structure size is dictated by wavelength of the rf accelerating wave. Wakefields related to structure size; thus so is the difficulty in controlling emittance growth and final luminosity.  Bunch spacing, train length related to rf frequency  Damping ring design depends on bunch length, hence frequency Specific Machine Realizations Frequency dictates many of the design issues for LC

16. 11-July-05 ACFA Workshop - Barish 16 Cost Breakdown by Subsystem Civil SCRF Linac

17. 11-July-05 ACFA Workshop - Barish 17 What Gradient to Choose?

18. 11-July-05 ACFA Workshop - Barish 18 TESLA Cavity 9-cell 1.3GHz Niobium Cavity Reference design: has not been modified in 10 years ~1m

19. 11-July-05 ACFA Workshop - Barish 19 (Improve surface quality -- pioneering work done at KEK) BCPEP Several single cell cavities at g > 40 MV/m 4 nine-cell cavities at ~35 MV/m, one at 40 MV/m Theoretical Limit 50 MV/m Electro-polishing

20. 11-July-05 ACFA Workshop - Barish 20 Gradient Results from KEK-DESY collaboration must reduce spread (need more statistics) single-cell measurements (in nine-cell cavities)

21. 11-July-05 ACFA Workshop - Barish 21 How Costs Scale with Gradient? Relative Cost Gradient MV/m 35MV/m is close to optimum Japanese are still pushing for 40- 45MV/m 30 MV/m would give safety margin C. Adolphsen (SLAC)

22. 11-July-05 ACFA Workshop - Barish 22 Evolve the Cavities Minor Enhancement Low Loss Design Modification to cavity shape reduces peak B field. (A small Hp/Eacc ratio around 35Oe/(MV/m) must be designed). This generally means a smaller bore radius Trade-offs (Electropolishing, weak cell-to-cell coupling, etc) KEK currently producing prototypes

23. 11-July-05 ACFA Workshop - Barish 23 New Cavity Design More radical concepts potentially offer greater benefits. But require time and major new infrastructure to develop. 28 cell Super-structure Re-entrant single-cell achieved 45.7 MV/m Q 0 ~10 10 (Cornell)

24. 11-July-05 ACFA Workshop - Barish 24 Fermilab ILC SCRF Program

25. 11-July-05 ACFA Workshop - Barish 25 Experimental Test Facility - KEK Prototype Damping Ring for X-band Linear Collider Development of Beam Instrumentation and Control

26. 11-July-05 ACFA Workshop - Barish 26 Final Focus Test Faclity - SLAC

27. 11-July-05 ACFA Workshop - Barish 27 TESLA Test Facility Linac - DESY laser driven electron gun photon beam diagnostics undulator bunch compressor superconducting accelerator modules pre- accelerator e - beam diagnostics 240 MeV120 MeV16 MeV4 MeV

28. 11-July-05 ACFA Workshop - Barish 28 ILC Siting and Civil Construction The design is intimately tied to the features of the site –1 tunnels or 2 tunnels? –Deep or shallow? –Laser straight linac or follow earth’s curvature in segments? GDE ILC Design will be done to samples sites in the three regions –North American sample site will be near Fermilab –Japan and Europe are to determine sample sites by the end of 2005

29. 11-July-05 ACFA Workshop - Barish 29 Fermilab ILC Civil Program A Fermilab Civil Group is collaborating with SLAC Engineers and soon with Japanese and European engineers to develop methods of analyzing the siting issues and comparing sites. The current effort is not intended to select a potential site, but rather to understand from the beginning how the features of sites will effect the design, performance and cost

30. 11-July-05 ACFA Workshop - Barish 30 Draft27-May-05 Conventional Facilities Site Considerations 1 Site impacts on critical science parameters 5 Construction Cost Impacts (cont.) 1A1A Configuration (Physical Dimensions and Layout) 5C5CClimate.1Usable Length and Width.1.1Snowfall.2Flexibility for Adjustment of Alignment.2.2Average Ambient temperature.a Adaptable to Laser Straight.3.3Average underground temperature.bAdaptable to Earth Curvature.4.4No of days rainfall.3Depth of Tunnel 5D5DEnvironmental Restrictions.4Depth of Interaction Halls 5E5EAccessibility.5Accessibility to Tunnels 5F5FSite Utility Support & Installation 1B1BPerformance (Vibration and Stability 5G5GProximity of Soil Borrow and Disposal Areas.1Natural Vibration/Noise Sources 5H5HLocal Labor.aGeologic Dynamic Properties.1.1Construction Rate Index

31. 11-July-05 ACFA Workshop - Barish 31 Parameters of Positron Sources rep rate # of bunches per pulse # of positrons per bunch # of positrons per pulse TESLA TDR5 Hz28202 · 10 10 5.6 · 10 13 NLC120 Hz1920.75 · 10 10 1.4 · 10 12 SLC120 Hz15 · 10 10 DESY positron source 50 Hz11.5 · 10 9

32. 11-July-05 ACFA Workshop - Barish 32 B=0.75 T 5 mm gap Conventional source Undulator-based source Positron source

33. 11-July-05 ACFA Workshop - Barish 33 Laser Compton Source

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37. 11-July-05 ACFA Workshop - Barish 37 Beam Delivery Systems -- Challenges Transport the high-energy beam from the end of the main linac to the interaction point Transport the post-collision spent beam and beamstralung to the dumps Provide collimation for control of backgrounds Provide machine protection systems for errant beams Provide collision point maintenance through the use of fast feedback systems (inter-train and intra-train)

38. 11-July-05 ACFA Workshop - Barish 38 20 mrad ILC FF9 (x 4) tuneup dump lines ILC Strawman Layout Mark Woodley

39. 11-July-05 ACFA Workshop - Barish 39 Accelerator Physics Challenges Develop High Gradient Superconducting RF systems –Requires efficient RF systems, capable of accelerating high power beams (~MW) with small beam spots(~nm). Achieving nm scale beam spots –Requires generating high intensity beams of electrons and positrons –Damping the beams to ultra-low emittance in damping rings –Transporting the beams to the collision point without significant emittance growth or uncontrolled beam jitter –Cleanly dumping the used beams. Reaching Luminosity Requirements –Designs satisfy the luminosity goals in simulations –A number of challenging problems in accelerator physics and technology must be solved, however.

40. 11-July-05 ACFA Workshop - Barish 40 Test Facility at KEK

41. 11-July-05 ACFA Workshop - Barish 41 Test Facility at SLAC

42. 11-July-05 ACFA Workshop - Barish 42 TESLA Test Facility Linac - DESY laser driven electron gun photon beam diagnostics undulator bunch compressor superconducting accelerator modules pre- accelerator e - beam diagnostics 240 MeV120 MeV16 MeV4 MeV

43. 11-July-05 ACFA Workshop - Barish 43 Fermilab ILC SCRF Program

44. 11-July-05 ACFA Workshop - Barish 44 “Our task is to continue studies on physics at the linear collider more precisely and more profoundly, taking into account progresses in our field, as well as on developments of detector technologies best suited for the linear collider experiment. As we know from past experiences, this will be enormously important to realize the linear collider.” Akiya Miyamoto ACFA Joint Linear Collider Physics and Detector Working Group

45. 11-July-05 ACFA Workshop - Barish 45 Higgs Coupling and Extra Dimensions ILC precisely measures Higgs interaction strength with standard model particles. Straight blue line gives the standard model predictions. Range of predictions in models with extra dimensions -- yellow band, (at most 30% below the Standard Model The models predict that the effect on each particle would be exactly the same size. The red error bars indicate the level of precision attainable at the ILC for each particle Sufficient to discover extra dimensional physics.

46. 11-July-05 ACFA Workshop - Barish 46 Beam Detector Interface Tauchi LCWS05

47. 11-July-05 ACFA Workshop - Barish 47 The Machine Accelerator baseline configuration will be determined and documented (BCD) by the end of 2005 R&D program and priorities determined (proposal driven) Baseline configuration will be the basis of a reference design done in 2006 The Detector(s) Determine features, scope: one vs two, etc (same time scale) Measure performance of the baseline design Beam delivery system and machine detector interfaces Define and motivate the future detector R&D program The GDE Plan