Minutes of 54th FFIR/BDSIM meeting on 6/11/2003

The meeting was held in a room of 425 at KEK, 13:30-15:00, 6/11/2003. We discussed on Ground motion model, FEATHER, beam scattering at LINAC and others.

(1) Ground Motion Measurement at KEK (H.Yamaoka, KEK)

(transparencies, 15 pages, pdf ,15.9MB ) Yamaoka reported preliminary results on the ground motion measurements which have been done in December,2002 through January ,2003, by collaboration of KEK, university of Tokyo and Electric Power Development Co., Ltd. . Major measurement points are four places on ground surface and -10m underground along the TRISTAN ring, which are D3, Oho, D9 and D12. So, the longest distance is about 1km between D3 and D9. D3 is nearest to route 408 (Higashi-Odori). There are 4 sensors (P1,P2,P3 and P4) of VSE-355 G2 (velocity, Tokyo Sokushin Co.) whose frequency range and resolution are 0.012-70Hz and 10-6gal, respectively. These sensors have been calibrated to check their performances before the measurements.

At this time, he reported a measurement at D3 and a coherency measurement between the four points. Data sampling frequency and duration are 100Hz and 600sec, respectively. At the D3, P4 and P3 were set on ground surface at distances of 4m and 15m from route 408, respectively. P2 and P1 were set on the floor and -10m underground floor, respectively, in a building of "D3" power station. Ground motions were measured every hour in a day. As expected, the P1 was the most quiet, where the GM tolerances (250nm at 0.1Hz, 10nm at 10Hz) were only satisfied during a day. The P4 was the noisiest, which was actually noisier three times than the P3 at f>10Hz. Good correlation in the daily variations was observed between measurements and total weight rather than total number of cars passing through on the route 408 , assuming weights of car, truck and big truck are 1.5, 10 and 30 tons, respectively. The vehicle traffic has been recorded on a video tape. Horizontal attenuation was observed to be 3/5~2/3 for 11m from P4 to P3 at f=0.1~10Hz. As a resonance frequency of soil corresponding to GM amplification in earth quake, H/V PSD ratios were also calculated to be about 6 at a peak at f=0.5Hz. Finally, good coherency in large distances, e.g. 1km of D9-D3, were observed at f<0.3Hz.

(2) FEATHER: Status Report (N.Delerue, KEK)

(transparencies, 13 pages, pdf ,815KB ) Nicolas reported on the progresses of kicker design, estimation of model delays, MATLAB simulation and beam tests. He summarized and will publish the kicker design in a KEK report. The technical drawings have been reviewed and validated, while the impedance at bolting points will be very low. Delay times in the FEATHER have been estimated as in a following table.
------- Delay time in nsec  --------------------
Model:      Simple                 Delay
cable      5cablesx1.4= 7   7cablesx1.4= 9.8
HH107      2 HH107    = 0.5 4 HH107    = 1.0
Att.                  < 1.0            < 1.0
Amplifier  estimated   20               20
Total                  28.5             31.8
So, the amplifier dominates in above list and next major component is the cable delay to be improved with shorter cables. The fast amplifier is primary requirement for the purchase. He simulated the feedback models by using MATLAB including the beam signals with position offsets. In the beam test, he has investigated communication problems with the GPIB devices and the ATF_CONTROL. The GPIB problem were fixed and the software has been tested. The ATF_CONTROL problem has been understood and seems to be fixed but more tests are needed. Next beam test will be in October.

The next meeting will be on 2 July (Wed.), 2003,10:00 - noon at 3 gokan, 425 .