Instability measurement plans at ATF Junji Urakawa ( for collaborators ) at ILC Damping Rings Workshop – ILCDR07 2019/2/25 3rd ILCDR07

Experimental condition for single bunch instability study at ATF Damping Ring Bunch intensity : 0.3 to 3 x 1010 electrons/bunch Bunch length : 5mm to 10mm Energy spread : 0.06% to 0.1% Transverse emittance : ~1nm horizontally, ~10pm vertically Necessary effort to achieve above condition: 1. Upgrade of ATF Linac injector system : we will change modified photo-cathode RF gun in coming spring. 2. Damping Ring beam tuning to keep a good flat beam. 3. Control on-coupling and off-coupling to evaluate intra-beam effect. 2019/2/25 3rd ILCDR07

Photo-cathode RF Gun Manufacture for New injector of KEK-ATF 2001 2007 2019/2/25 3rd ILCDR07

ATF Beam Diagnostic System for single bunch instability study XSR monitor Bunch length monitor (Bunch profile) CSR monitor Precise energy spread monitor at Extraction line Current monitor,--- 2019/2/25 3rd ILCDR07

Measured beam profile by XSR monitor in normal vacuum condition Single bunch/single train , 2×1010 bunch/train Ave: 2×10-7 Pa X : 49.5±2.3 mm Y : 8.1±0.7 mm This profile was appeared on normal beam operation 2019/2/25 3rd ILCDR07

Bunch Length Measurement (Synchronized Streak Camera) 2019/2/25 3rd ILCDR07

CSR monitor location Remove all wigglers and replace the chambers to BH1R.10 Detector block Waveguide BH1R.11 SD1R.10 QM21R.1 SF1R.10 QM20R.1 Ceramic flange Waveguide corner block Remove all wigglers and replace the chambers to circular one. Wiggler Z H 1 8 R V L W . 2 3 4 M 9 T Q F 5 D o v a b l e B m - u p ( X ) Z H 9 R S F 1 . D 8 V 7 6 Q M 2 3 B P 4 Z W 2 R S F 1 . D 3 9 Q M 8 B P V H 4 5 B W 1 R . 2 3 Z Z V 1 9 R Q F 2 . 8 H 7 M ( 6 ) 5 4 3 6 B P M . 2 7 8 9 3 1 4 Z V R 5 Q F M S 4 T Z H 5 8 M B 1 T K I S 3 . 2 9 C H X ( Z 5 ) 4 B P M . 1 5 6 H R 9 8 2 3 4 Q F 1 X B S 2 ( Z ) 3 H . D V 6 C K I M T 1 X Z V 5 C 2 4 ( S ) L B H 7 o m p t n h a b e r 6 x , y Q K 3 W K Z H 2 X K I C E R Q F 3 4 D 5 6 V 7 8 1 9 B e a m u p M L M L 9 X 1 3 4 ( S 6 ) 5 H i g h R e s W 2 C E 1 R V Z 3 X Z Z Z H 9 V H 4 X X 5 X 2019/2/25 3rd ILCDR07 Q 5 F X

Spectrometer Stage SBD Set of 11 Mesh Filter Synchrotron radiation Set of 11 Mesh Filter Freq. range 90 to 140GHz with 5GHz step on center frequencies Specifications: 3dB attenuation at  5% From center frequency Center frequency transmission 100% Dimensions: 30mm X 30mm Stage SBD To the Amp 2019/2/25 3rd ILCDR07

Results measured at ATF DR so far 2019/2/25 3rd ILCDR07

Bunch length 5mm to ~10mm R~ 1kW L~20nH to 50nH By 1998 to 2001 measurements 2019/2/25 3rd ILCDR07

Requests for instability study from 2008 to 2009 Preparation for single bunch instability is ready. We need several shifts of machine time in 2008 and 2009. Welcome the evaluation of existing impedance before fast kicker system installation. (need a good coordination.) Most important issue is very good beam tuning for stable operation on coupling-resonance and off-resonance (flat-beam). 2019/2/25 3rd ILCDR07