ATF2 weekly meeting

Wednesday 3 Sept 2008, 14:30 → 16:30 Asia/Tokyo

Minutes (7 Oct.08) d080903.html

14:30 → 15:30 International phone/webex meeting

14:30 First Alignment of Downstream ATF2 magnets

Speaker: Mr Ryuhei Sugahara (KEK)

Slides ATF2_align_080819-27.pdf ATF2_align_080819-27.ppt

14:50 Progress of Shintake monitor

Speaker: Mr Takashi Yamanaka (The University of Tokyo)

Slides Progress_of_Shintake_Monitor.pdf Progress_of_Shintake_Monitor.ppt

Conclusion of slides * Performance tests regarding optics were done and dominant error soruces of beam size measuremen are evaluated. 1. Laser interference visibility is 100 % 2. Position jitters at the IP are 3.2 um in vertical and 1.9 um in beam axis. They cause the power jitter at the IP but it is small enough. 3. Phase jitter at the IP is expected to about 300 mrad even if we perform the phase stabilization, which is a little bit large for our goal of the phase stability (200 mrad). Q: The electron beam comes in 1.5 Hz but you use the 10 Hz pulsed laser. How do you adjust the timing of them? A: We shot laser pulses when the beam doesn't comes and also perform the phase stabilization. Only when the beam comes we adjust the laser shot timing to the beam. Q: How do you adjust the laser timing to the beam? A: We need to construct the laser trigger system from now, so we can't answer now.

15:10 Discussion : Plan for a special ATF2 project meeting, 1 Oct., KNU

Also, discuss on dates of ATF2 project meeting in this December

Special ATF2 project meeting http://ilcagenda.linearcollider.org/conferenceDisplay.py?confId=2877

15:30 → 16:30 KEK site meeting (Japanese)

15:30 Progress of Shintake monitor work

Speakers: Mr Masahiro OROKU (Tokyo Univ.), Mr Takashi Yamanaka (The University of Tokyo)

Slides Progress_of_Shintake_Monitor.pdf Progress_of_Shintake_Monitor.ppt

Slides by Takashi Yamanaka Participants: Tauchi, Terunuma, Kuroda, Okugi, Yamanaka, Kamiya(WebEx) Topic: Phase Stability Measurement using Phase Monitor * Phase measurement has done by using the CW laser to remove the effect of laser angular jitter. * Phase monitor ch2 seems to have less phase search resolution. * As a result, phase jitter pulse by pulse disappeard but the seconds order vibration remained althogh the phase stability in 1 min is improve to 170 mrad. * Phase drift in long time has no correlation to the air temperature. * If I hammer the optical table lightly, phase jump was observed. And also the vibration source was put near the optical table on purpose, the phase stability was degenerated to 260 mrad in this case. * From the frequency analysis phases of two monitors has a clear inverse correlation below 0.01 Hz and above this frequency the correlation getting worse. Suggestion: To clear the cause of phase drift, longer measurement (longer than 1 day) is needed. Suggestion: To make the measurement reliable, you need to do performance test of phase monitor.