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Accelerator R&D on LC- Activities of ATF & STF -

1. Introduction2. ATF3. STF4. Summary

Seiya Yamaguchi, KEK

The US/Japan Collaboration in High Energy Physics

The 30th Anniversary Symposium, Oct. 20-21, 2010

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1. Introduction

for precise beam generation, control

STFATFfor superconducting

acceleration

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2. ATF1995 Linac completed 1997 Ring completed 2002 RF Gun installed 2008 ATF2 completed

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IP-BSM (KEK, U. Tokyo, SLAC, UK)

FFTB Shintake BSM (1994)Significantly improved 1,064 nm → 532 nm sy=70 nm → 35 nm

sy=310±30(stat.)+0-40(sys) nm (July, 2010)

signal pattern of Compton g

pattern depends on beam size

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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 2009. Extracted 30 bunches from DR. Jun.10

Tr~2.2 ns

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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.

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Fast Feedback (KEK, SLAC)(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

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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.

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High Gradient SC Cavity Development 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

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Camera for observation of inner surface(KEK, Kyoto U, FNAL, JLAB)

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

FNAL JLAB

defect

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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. 2010. Delivered to KEK Sep. 2010.

training at FNAL (Feb 2010) Delivered to at KEK (Sep.2010)

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Production of ultra-low emittance beamDevelopment 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).

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• Established many advanced accelerator

technologies for high quality beam and

superconducting acceleration.

4. Summary