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

2. 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

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

4. 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

5. 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

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

7. 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

8. 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

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

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

11. 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