1 1 H. Hayano and ATF group ATF Status August/2004 H. Hayano and ATF group Multibunch emittance Instrumentation developments Plans for run Multibunch emittance Instrumentation developments Plans for run 第１回加速器学会年会 8/04/2004

2 ATF Introduction Multibunch Photo-cathode RF gun,  f-ECS S-band Linac GLCTA beam line expansion E=1.28GeV Ne=1x10 10 e-/bunch 1 ~ 20 bunches Rep=1.5Hz X emit=2.5E-6( at 0 int.) Y emit=2.5E-8( at 0 int.) E=1.28GeV Ne=1x10 10 e-/bunch 1 ~ 20 bunches Rep=1.5Hz X emit=2.5E-6( at 0 int.) Y emit=2.5E-8( at 0 int.) ATF Damping Ring

3 Single bunch Transverse Emittance by Laser wire X emittance determined by Ring Design. Measured data points are fit to simulation. Y emittance =6.5pm at GLC intensity, is below GLC design.

4 Multibunch photo-cathode RF gun Gun cavity High quality Multibunch beam is generated.

5 Multibunch emittance Beam intensity in DRBeam intensity in DR ~ 0.7 x10 10 e -, 20 bunch, 2.8ns spacing with 0.78Hz repetition Monitors of MB emittanceMonitors of MB emittance MB (or projected) Laser-wire Projected SR interference monitor, X-ray SR monitor Fast Ion effect on MB emittanceFast Ion effect on MB emittance big energy fluctuation at tail bunch big projected emittance at tail bunch Beam intensity in DRBeam intensity in DR ~ 0.7 x10 10 e -, 20 bunch, 2.8ns spacing with 0.78Hz repetition Monitors of MB emittanceMonitors of MB emittance MB (or projected) Laser-wire Projected SR interference monitor, X-ray SR monitor Fast Ion effect on MB emittanceFast Ion effect on MB emittance big energy fluctuation at tail bunch big projected emittance at tail bunch

6 Major emittance monitors Tungsten Wire Scanner Laser Wire Scanner SR Interference Monitor X-ray SR Monitor

7 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

8 Multibunch Vertical Emittance by Laser wire Blowup at tail bunch is seen.

9 Preliminary result of Fast Ion Instability simulation Behavior of Y emittance is very similar. Schematic of the Fast-Beam Ion Instability simulation

10 DR vacuum pressure Low emittance was observed at DR pressure < 4 x10 -7 Pa Emittance growth observed with vacuum pressure > 4 x10 -7 Pa, even small bunch charge. Low emittance was observed at DR pressure < 4 x10 -7 Pa Emittance growth observed with vacuum pressure > 4 x10 -7 Pa, even small bunch charge. 20 bunch, 1 train = 52mA ~15 A.hour (ex. 150mA.100hours)

11 DR scrubbing status GLC intensity: 20 bunch, 1 train = 52mA: 3 train = 156mA ~5.5 A.hour 45 hours 150mA EXT kicker pressure dominant 6/12/2004 ~ 6/14/2004

12 Multibunch Vertical Emittance after 9.3 A.hours scrubbing Projected Y emittance is around 1% from X, However, insufficient tuning of Y emittance.

13 Emittance of each bunch after 9.3 A.hours scrubbing No big tail rise was seen, However, insufficient tuning of Y emittance. Scrubbing seems to be effective

14 Instrumentation developments ODR beam size monitorODR beam size monitor beam size measurement was performed. FEATHER / FONT studyFEATHER / FONT study basic data taking of collision feedback nm resolution cavity-BPMnm resolution cavity-BPM 3 cavity BPM setup (SLAC, KEK) under commissioning, under installation ODR beam size monitorODR beam size monitor beam size measurement was performed. FEATHER / FONT studyFEATHER / FONT study basic data taking of collision feedback nm resolution cavity-BPMnm resolution cavity-BPM 3 cavity BPM setup (SLAC, KEK) under commissioning, under installation

15 ODR(Optical Diffraction Radiation) beam size monitor beam size monitor Achieved resolution ~10µm

16 FEATHER stripline Kicker FEATHER BPM Fast feedback control study for collision feedback for collision feedback FEATHER(KEK), FONT(UK) Collision feedback

17 Cavity BPM nm resolution study (SLAC) LLNL Design mover, Improved electronics, installed Mar Still under commissioning

18 KEK nm-BPM study 3 cavity BPM system 1 cavity BPM under checking. 1 mover stage done. 2 more under fabrication. Active mover & nm sensor are preparing. Reference monitor & optical anchor is under study. KEK cavity BPM Active Mover & nm sensor & nm sensor

19 Other Developments in ATF Wiggler studyWiggler study Additional correction PS for residual kick is preparing. Damping time and emittance will be tested in fall-run. X-Y coupling at extractionX-Y coupling at extraction Multi-pole component of kicker and septum is under study. S-band detuned structure studyS-band detuned structure study Basic study of new detuned method is now under way. Fast sweep LW at EXT plan (UK)Fast sweep LW at EXT plan (UK) Fast sweep over multibunch scan is now under planning. Laser pulse stacking method for LWLaser pulse stacking method for LW Pulse stacking chamber is now under installation. Wiggler studyWiggler study Additional correction PS for residual kick is preparing. Damping time and emittance will be tested in fall-run. X-Y coupling at extractionX-Y coupling at extraction Multi-pole component of kicker and septum is under study. S-band detuned structure studyS-band detuned structure study Basic study of new detuned method is now under way. Fast sweep LW at EXT plan (UK)Fast sweep LW at EXT plan (UK) Fast sweep over multibunch scan is now under planning. Laser pulse stacking method for LWLaser pulse stacking method for LW Pulse stacking chamber is now under installation.

20 ATF Plans for MB emittance studyMB emittance study More small Y emittance will be confirmed soon. More small Y emittance will be confirmed soon. Wiggler studyWiggler study Damping time and emittance will be confirmed with wiggler ON. Damping time and emittance will be confirmed with wiggler ON. Extraction of low emittance beamExtraction of low emittance beam multi-pole component of kicker and septum are under study. multi-pole component of kicker and septum are under study. nm resolution BPM test & demonstrationnm resolution BPM test & demonstration Development of new precise mover & new cavity-BPM electronics(SLAC). Development of new precise mover & new cavity-BPM electronics(SLAC). KEK version of cavity BPM and active mover development are under way. KEK version of cavity BPM and active mover development are under way. combination of two system for study of active stabilization. combination of two system for study of active stabilization. Fast feedback test & demonstrationFast feedback test & demonstration Basic test of feedforward and feedback are under way. (FEATHER/FONT) Basic test of feedforward and feedback are under way. (FEATHER/FONT) Fast feedback test by 3 train extraction will be done. Fast feedback test by 3 train extraction will be done. Instrumentation developmentsInstrumentation developments LW(Kyoto, UK), XSR monitor, ODR monitor, MB-BPM, etc. LW(Kyoto, UK), XSR monitor, ODR monitor, MB-BPM, etc. MB emittance studyMB emittance study More small Y emittance will be confirmed soon. More small Y emittance will be confirmed soon. Wiggler studyWiggler study Damping time and emittance will be confirmed with wiggler ON. Damping time and emittance will be confirmed with wiggler ON. Extraction of low emittance beamExtraction of low emittance beam multi-pole component of kicker and septum are under study. multi-pole component of kicker and septum are under study. nm resolution BPM test & demonstrationnm resolution BPM test & demonstration Development of new precise mover & new cavity-BPM electronics(SLAC). Development of new precise mover & new cavity-BPM electronics(SLAC). KEK version of cavity BPM and active mover development are under way. KEK version of cavity BPM and active mover development are under way. combination of two system for study of active stabilization. combination of two system for study of active stabilization. Fast feedback test & demonstrationFast feedback test & demonstration Basic test of feedforward and feedback are under way. (FEATHER/FONT) Basic test of feedforward and feedback are under way. (FEATHER/FONT) Fast feedback test by 3 train extraction will be done. Fast feedback test by 3 train extraction will be done. Instrumentation developmentsInstrumentation developments LW(Kyoto, UK), XSR monitor, ODR monitor, MB-BPM, etc. LW(Kyoto, UK), XSR monitor, ODR monitor, MB-BPM, etc.

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