Michael and Yuhang

We recovered filter cavity alignment. While doing the recoverment, we found some issues of picomotors. Especially, the BS yaw had problem. The problem is when we move yaw, the actual motion was pitch. The solution is to disconnect the pitch control wire. Then when we move yaw, we can really move it.

After recovering mirrors positions, we got cavity flash as attached figure 1. Then we centered all oplev signals on each PSD. After that, the medm interface is shown in the attached figure 2. In the end, we also measured the spectrum of each oplev signal. FIgure 3 shows the comparison with old measurement. No issues were found.