This afternoon, Valerio injected a line at 0.1 Hz on SDB1 along the longitudinal axis, by acting at the top of the suspension.

The following data have been taken:

• Motion on SDB1 = +/-10 um, Start time = 15:40:00 UTC,  duration = 120 s
• Motion on SDB1 = +/-15 um, Start time = 15:43:00 UTC,  duration = 180 s
• Motion on SDB1 = +/-20 um, Start time = 15:47:30 UTC,  duration = 210 s

Figure 1 shows a time series of the bench Z motion during the injections. Channel TX has been plotted to check that the cross coupling between Z and TX is negligible.

Figure 2 shows a comparison of the DARM spectrum before the injections and at the time of the loudest injection.

We will use this data to extract the coupling factor of scattered light.