Accelerator R&D on LC - Activities of ATF & STF - 1. Introduction 2. ATF 3. STF 4. Summary Seiya Yamaguchi, KEK The US/Japan Collaboration in High Energy Physics The 30th Anniversary Symposium, Oct ,

1. Introduction for precise beam generation, control STF ATF for superconducting acceleration 2

2. ATF 1995 Linac completed 1997 Ring completed 2002 RF Gun installed 2008 ATF2 completed 3

IP-BSM (KEK, U. Tokyo, SLAC, UK) FFTB Shintake BSM (1994) Significantly improved 1,064 nm → 532 nm  y =70 nm → 35 nm  y =310±30(stat.)+0-40(sys) nm (July, 2010) signal pattern of Compton  pattern depends on beam size 4

Fast Kicker (KEK, SLAC) rise/fall time less than 3 ns. US team (SLAC) to develop high-speed pulsed power supplies. (10 kV) KEK to develop strip-line electrode. Tested at ATF DR since Extracted 30 bunches from DR. Jun.10 T r ~2.2 ns 5

6 Cavity BPM for use at IP (KEK) Create a reference at IP instead of colliding beam Need 2 nm resolution Rectangular cavity → X-Y separation Achieved resolution 8.7 nm ±0.28(sta.)±0.35(sys), dynamic range ~ 5 μm Temperature stabilization, high bunch intensity and beam orbit stabilization are necessary to improve the resolution.

Fast Feedback (KEK, SLAC) 7 (FONT : Feedback On Nanosecond Time scale) Feedback and Feed forward will be used to straighten the train. FONT : latency estimate - irreducible latency=14 ns - electronics latency=118 ns - total latency of FB loop =132 ns < 154 ns FB OFF FB ON Bunch spacing=154 ns

8 3. STF Improve performance of superconducting cavity Demonstrate superconducting Accelerator System - high gradient - high Q-value - SC cavity - RF source - Cryo system - e - gun - Monitor - etc.

High Gradient SC Cavity Development 9 VT at JLAB S1-Global at KEK - demonstrate plug compatibility - operate at 31.5 MV/m - two cavities from FNAL, two from DESY KEK supplies 4 cavities - KEK cavity tested at JLAB - assembly completed, RF test in CM on going. 12 MV/m at KEK 27 MV/m at JLAB

Camera for observation of inner surface (KEK, Kyoto U, FNAL, JLAB) 10 To find defect, contamination in cavity FNAL introduced the inspection camera. KEK loaned the camera to JLAB for 1 year. Improvement of the camera for more bright image and high resolution FNALJLAB defect

11 Pre-tuning machine for 9-cell cavity SC : deep drawing → deform cavity shape FNAL-DESY-KEK collaboration Hardware and Software fabrication are complete. Training course at FNAL on Feb Delivered to KEK Sep training at FNAL (Feb 2010) Delivered to at KEK (Sep.2010)

12 Production of ultra-low emittance beam Development of RF gun Fabrication of 1.3 GHz photocathode RF gun by FNAL-KEK, based on DESY design. RF cavity, Input coupler (FNAL). Photocathode and solenoid fabricated (KEK). Beam test in 2011 at STF (KEK).

Established many advanced accelerator technologies for high quality beam and superconducting acceleration Summary