I measured the transfer functions of the GAS filters in PRs and compared each other. There is not much difference between the three suspensions except the DC magnitude in SF. 

I measured the transfer functions of the IMs in PRM and PR3 and compared each other. There is not much difference between the two suspensions except the vertical TF (V-V). The vertical TF should be the same as the BF GAS TF (klog). The V-V TF in PRM has no recoil mode from the SF stage. It should be checked more.

I measured the transfer functions of the TMs in PRs during 5/18-19 and compared each other. Since the calibration factors of PR2 OpLev have not been input into MDEM yet, the DC gains were corrected by the measured factor. There were no large differences in the TF shape. Alignment to the OpLev was not good enough to obtain good SNR. The DC gains also have a variation of +/- 10dB.

I compared the spectra of the sensors in ALIGNED mode.

• The noise floors of LVDTs and OSEMs at the higher frequencies are almost consistent.
• The SF and BF GAS filters are well damped in PR2.
• The magnitude of the BF GAS LVDT and the IM vertical OSEMs are large at 1-3Hz in PR2.
• The IM vertical OSEMs and the TM pitch OpLev have a broad peak at 4Hz in PR3.

I compared the spectra in SAFE mode additionally in PR2 and PR3.

• The magnitude of the BF GAS LVDT and the IM vertical OSEMs are decreased at 1-3Hz in PR2. It may be due to the control.
• The broad peaks at 4Hz disappear except for sharp ones in PR3. It may be due to the control (e.g. servo bump).

I measured the transfer functions of the BF GAS and the IM vertical in PRM. In the last measurement, the IM vertical TF (V-V) was different from the BF GAS TF. At this time, both TFs became consistent; they have the recoil mode from the SF stage.