1. Status of ATF Collaboration The unique test facility for ILC with a low emittance beam. Junji Urakawa, KEK LCPAC at KEK 2006.3.25

2. 1 ATF Collaboration History ATF Construction and R&D’s have been started with SLAC from 1993. From 1997 International collaboration started for the R&D’s with Damping Ring. ATF MoU was established on 1 st Aug. 2005. New organized ATF international collaboration has been started. (20 Institutes or more were signed.) 1 st ICB meeting in Snowmass, 1 st TB meeting at KEK on Dec.. 2 nd TB meeting will be scheduled in May after ILC school. From 2008, ATF2 : the final focus test beam line, will be operated.

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5. 4 Assignment of the ATF Beam Time TB: Approved Studies ~2/3 SP: Approved Studies Beam Tuning Maintenance Typical ~22 weeks/year About 20 % of total will be used for the maintenance and the beam tuning. It is estimated by current results. Guideline for approved studied by SP. 1.Short term study 2.No conflict with approved studies by TB and ICB. 3.Test study for new proposal 4.SP can accept until two shifts/week but it depends on the situation of studies.

6. 5 Schedule of ATF operation, TB meeting and Long shutdown

7. 6 Mission of ATF 1.Establish the technologies associated with producing the electron beams of the quality required for ILC. 2.Provide such beams to ATF2 in a stable and reliable manner. 3.Serve the mission of providing the young scientists and engineers with training opportunities of participating in R&D programs for advanced accelerator technologies.

8. 7 ATF Accelerator Test Facility

9. 8 R&D items in ATF 1. kicker study for extraction of ILC-like bunch spacing.1. kicker study for extraction of ILC-like bunch spacing. Multi-pole component of kicker and septum is under study. kicker study for ILC Damping Ring.2. Fast rise/fall strip-line kicker study for ILC Damping Ring. <3ns rise/fall is under study. 3. High resolution Ring-BPM for more small vertical emittance.3. High resolution Ring-BPM for more small vertical emittance. application of digital signal process is under study. 4. Coherent Synchrotron Radiation(CSR) study. development of CSR detection is underway. 5. Cavity BPMs.5. Cavity BPMs. nm resolution BPMs, PAL-BPM at ATF2, IP-BPM at ATF2. 6. Laser Wire beam size monitor.6. Laser Wire beam size monitor. Fast sweep LW at EXT-line, Shintake-monitor at ATF2. 7. Fast orbit feedback for ILC collision point.7. Fast orbit feedback for ILC collision point. digital feedback method is under development. 8. Many other instrumentation(ODR, XSR, LW@DR)8. Many other instrumentation(ODR, XSR, LW@DR) 9. S-band RF-gun study for stable injection into ATF-DR.9. S-band RF-gun study for stable injection into ATF-DR. 10. Pol. positron generation R&D based on Compton scattering.10. Pol. positron generation R&D based on Compton scattering. 11. Fast Ion Instability Measurement 12. Multi-bunch Instability Study

10. 9 Highlight Studies in Extraction Line Stable beam extraction from DR –Kick angle compensation for multi-bunch, Double kicker system –Multi bunch extraction with ILC like beam spacing (2005~) –3 bunch extraction with 150ns spacing by 300ns flat-top double kicker. Instrumentation developments –Beam size monitors Optical Diffraction Monitor, Wire scanners (Tungsten, Carbon), Laser wire (UK, 2005~) –Nano meter resolution Beam position monitors : Cavity BPM Intra-train beam feedback –FONT (UK) / FEATHER (KEK) –Feed-forward to Extraction line from DR (UK, 2006~) Other R&D –Polarized positron generation Compton scattering with electron beam and polarized laser –Stabilization of components, Straightness monitor, StaFF (UK, 2006~) More new R&D in ATF will be proposed.

11. 10 Prospect of ATF ATF International R&D will generate necessary results for ILC, especially how to control high quality beam, develop many kinds of advanced instrumentation, educate young accelerator physicists and engineers. ILC like beam which means 20 bunches with bunch spacing about 300nsec, in the future. Realization of about 35nm beam for long period.

12. 11 2005.3.9 From US, EU, Russia, China, Korea, India and Japanese Univ., Many young physicists and engineers are learning and developing advanced accelerator technologies for ILC project. ATF Control Room

13. 12 Multi-bunch electron beam generation Gun cavity High quality Multi-bunch beam is generated. 1 ~ 20 bunches / pulse, 2.8ns spacing ~ 2 x 10 10 electrons / bunch

14. 13 Possibility of 1pm-rad  y Kubo's simulation: BPM offset error should be < 0.1 mm. (“BBA”) Then, εy ~ 2 pm will be achieved. Magnet re-alignment, < 30 μm. Then, εy ~ 1 pm will be achieved. Optics model should be good. Quad strength error should be < 0.5(?) % Measured in DR Single bunch Beam dynamics study

15. 14 Laser wire scanner in DR for X & Y scan, for single/multi-bunch TEM00 wire TEM01 wire Two optical cavity chamber For X-wire and Y-wire

16. 15 7 ‘y’ BPMs: 3 upgraded & 4 original Stored Beam – 10 minute time scale; ATF lifetime ~ few minutes

17. 16 ODR(Optical Diffraction Radiation) beam size monitor beam size monitor Achieved resolution ~10µm

18. 17 Fast Kicker Study Key component to determine the DR layout in Snowmass 17km, 6km, 3km 1.Kick the beam with the fast HV pulses. 2.Measure the beam oscillation by turn-by-turn BPM. 3.Timing scan to measure the pulse's time profile.

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20. 19 Extract the beam with ILC like bunch spacing Performance of the double kicker system has been confirmed by KEK kickers. Install the SLAC kickers modified for the double kicker system with 300ns (flat top) pulse in September 2005. Store 3 bunches in DR by 3 injections Injection kicker 60ns(rise/fall/flat-top) Extract beams in a kicker pulse Extraction kicker 60ns(rise), 300ns (flat-top) 150ns ILC like beam bunches for EXT line and ATF2 Beam Extraction Study

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23. 22 Two sets of triplets (z ~ 6m): SLAC/US/UK triplet KEK triplet Plan to test each individually – then connect (2006) Present results from both!

24. 23 Generic Cavity BPM Design: TM 11 -mode Selective Coupler Dipole frequency: 11.424 GHz Dipole mode: TM 11 Coupling to waveguide: magnetic Beam x-offset couple to y port Sensitivity: 1.6mV/nC/  m (1.6  10 9 V/C/mm) Couple to dipole (TM 11 ) only Does not couple to TM 01 –Low Q with narrow cavity gap –May need to damp TM 01 –OR, use stainless steel to lower Q signal Z. Li

25. 24 FFTB IP C-band cavity BPM triplet – this is the way to test BPM performa nce… T. Shintake - 1998

26. 25 Move BPM in 1 um Steps SLAC – upstream triplet – 17 nm resolution residual

27. 26 Development of Cavity BPM - KEK System –Three Cavity BPMs developed in KEK –Mover system with an active stabilization using an optical interferometer –Analog down conversion and phase detection electronics Performance –Resolution of the BPM: 17nm –Active mover stabilizes the system better than the resolution Downstream triplet – KEK Recent results:

28. 27 ATF Laser-wire Vacuum chamber built in Oxford and Installed in ATF extraction Line in December 2006. Laser light transported to IP, but no collisions yet seen; probably a detector issue. New run planned For April 06. Designing diagnostics insertion at Oxford

29. 28 LW Practical Considerations f1 geometry is challenging Limitations from power Limitations from angle Surface optical quality Alignment tolerance f1 Lens design is challenging Limitations from power Limitations from ghost images Alignment tolerance Lens currently under construction

30. 29 Feedback On Nanosecond Timescales (3) Adjustable-gap kicker BPM ML11X Feedbac k Superfast BPM processor Superfast amplifier BPM ML12X BPM ML13X Aim: TOTAL latency < 20 ns Oxford, DESY, CCLRC, KEK, Tokyo Metropolitan, SLAC ATF extraction line beam direction

31. 30 FONT1,2,3: Summary 67 ns 54 ns 23 ns Even fast enough for CLIC intra-train FB! May also be used at ILC