KAGRA vibration isolation meeting (1st of August 2012)

Attendees: DeSalvo, Hennes, Majorana, Takahashi, Uchiyama, Yamamoto

Riccardo: With Takanori, he measured the size of parts of the pre isolator
to look for the reason of the friction in the LVDT ([kagra-vi 00151]).
They found the extra filter base plate deformation (about 2mm), but nobody knows the
reason. Maybe, the material does not relax perfectly. When we buy them,
we must be careful (and re-relax ourselves at high temperature before).
Riccarod reported the result after this meeting [kagra-vi 00158].

Tomorrow, Riccardo et al proceed with the size measurement (for example,
the length of the legs)

Eric: Takanori reported the frequency of the bouncing mode. Although he
found the
peak at 97 Hz, but he was not so sure that it is the bouncing mode.
Eric measured his similar system. The load is about 150kg.
His measured result is 47Hz.

Ryutaro explained the progress after the previous vi meeting. The 97 Hz
mode is the
the bouncing mode (they used two sensors to invetigate the shape of the
mode).
But, according to the calculation, the fundamental bouncing mode is about
50 Hz.
They found some peaks around 50Hz. But unfortunately, the resonant modes
of the frame
are also around 50Hz. Eric wil send his result later [kagra-vi 00157].

Eric tried to measure IP transfer function using PZT, but it is not so
easy mission.

Riccardo proposed the actuator for the cryogenic mirror [kagra-vi 00154].
We will discuss later.