[Takano, Ushiba, Tanaka, Washimi]

We performed shaker injection tests for the ground around the OMC chamber.

At first, I tuned the excitation amplitude (70 counts, finally) to make the geophone signal about the same as the duct-shaking (40 counts) last Friday at 82Hz. 
Fig.2 is the comparison between the ground shaking and the duct shaking tests, for the geophone, the OMC error, and the OMC trans. They look almost the same. It means the noise increase by PEM injections is caused by the vibration of the OMC in-vac table.

The injection amplitude dependence of the induced noise for the 82Hz and 92Hz line injections are also performed.