M.Yamamoto,Sato,K.Yamamoto,and Tanaka

Date of measurement : 2023/3/3

In Yarm locked only,We excited elastic vibration resonances in ITMY and measured their peaks and Q-values.

In this measurement, resonance of two elastic vibration modes was confirmed.

Past Results

 ITMX measurement data log: https://klog.icrr.u-tokyo.ac.jp/osl/?r=23870

 ETMX measurement data log: https://klog.icrr.u-tokyo.ac.jp/osl/?r=23677

Procedure

To excite the elastic vibration of the ITMY, An excitation signal was input to the drive port of the high power coil driver of Test Mass stage of the ITMY.

The excitation signal was injected from moku.lab as an analog signal.

The elastic vibration signal was measured from test ports in the Common path of CARM Common Mode Servo  with FFT analizer and lock in amplifer.

Result

A resonance signal was confirmed at 23.6476 kHz and 34.3465 kHz.

Also, the decay time of the excitation signal indicated that

 at 23.6476 kHz

 the time constant is 0.24 seconds and Q-value is 1.8×10^4.

at 34.3465 kHz

 the time constant is 1.8 seconds and Q-value is 2.0×10^5.

(Each measurement was taken twice, and the time constant is shown as the average of the two measurements.)

Attachment

1. semilog graph with fitting of 23.6476 kHz.

2. semilog graph with fitting of 34.3465 kHz.

3.Damping graph at resonance frequency of 23.6476 kHz.

4.Damping graph at resonance frequency of 34.3465 kHz.