Floor Movement Measurement at ATF Ring ATF2 meeting at KEK December 19, 2006 Floor Movement Measurement at ATF Ring R. Sugahara, M. Masuzawa, H. Yamaoka Measured on October 31, 2006 P1

Floor movement was measured at the ATF ring on October 31, 2006 using two STS-2 seismometers of Streckeisen. - Spec. of STS-2 Range in frequency 0.008 – 50 Hz Sensitivity 15 V/kine (* kine = cm/sec) P2

Measurement Area (Max. L w/o exp. joint ~ 27m) X Y P3

at ATF Ring October 31, 2006 X Y P4

Power Spectral Density for L=0

Integrated Spectrum for L=0

<Coherency in X> (a) Huddling test <Coherency in X> (e) L = 12m 0.1 1 10 0.1 1 10 (b) L = 2m (f) L = 17m (c) L = 4m (g) L = 22m (h) L = 27m (d) L = 7m P7

<Coherency in V> (a) Huddling test (e) L = 12m 0.1 1 10 0.1 1 10 (b) L = 2m (f) L = 17m (c) L = 4m (g) L = 22m (h) L = 27m (d) L = 7m P8

<X-direction> <V-direction> Coherency when stamping (c) L=27m, quite (a) L=27m, quite 0.1 1 10 0.1 1 10 (b) L=27m, stamping at L=22m (d) L=27m, stamping at L=22m P9

=== Expansion joint === Coherency with Exp. Joint (a) Huddling test (e) Huddling test <X-direction> <V-direction> 0.1 1 10 0.1 1 10 (b) L = 1m (f) L = 1m === Expansion joint === (c) L = 3m (g) L = 3m (h) L = 5m (d) L = 5m P10

Estimated Frequency Area of Good Coherency versus Distance, L P11

Estimated Wave Velocity of Floor Motion Assuming: wave length ~ 2*L Velocity = 2*L*f P12

Summary - Floor movement was measured at ATF ring with two STS-2 seismometers. - Measurement was made at two points with various distances and coherency between two points was analyzed. - Coherent area in frequency was roughly estimated and plotted as a function of distance. - Assuming a distance (L) is a half of wave length, the velocity of the propagating wave was estimated. The velocity looks independent of L in X and vertical direction, and looks proportional to L in Y direction. What does this mean? - Coherency was also measured crossing an expansion joint of the floor. Plot of coherent area in frequency versus distance looks almost the same to that for measurement without crossing expansion joint. So the main source of the floor movement is speculated to be a motion of the earth, not the surface wave propagating the floor. P13

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L=3m across an expansion joint

L=3m across an expansion joint

<Y-direction> (a) Huddling test (e) L = 12m (b) L = 2m 0.1 1 10 0.1 1 10 (b) L = 2m (f) L = 17m (c) L = 4m (g) L = 22m (h) L = 27m (d) L = 7m