[Shimoda, Kokeyama, Nakano]

IMC came back!!

Today we succeeded to lock the IMC with the laser PZT. The polarization of laser was horizontal, so IMC was locked with low finesse mode.

First of today, the IMC was aligned with pico motors (pitch) and coils(yaw). Yesterday the resonance appeared already and a trans PD showed resonant peaks. The pico motors did not workd so well. Some of them stacked (I remember those are MCI yaw, MCO yaw, but not sure). Fortunately MC suspensions are soft to yaw and hard to pitch, so coils have enough range to align mirrors. Also the alignment didn't change so much from last locking.

Then IMC was locked for 30 minutes after we started to try.

We don't have enough time to investigate because of the preparation for power cuts on Monday. Next week we would have the super stable mode cleaner

Concerns
・As klog2917, the beam hits close the edge of viewport. 
・Today the cavity was locked with 500mW laser, but error signal was not really large. From next week, for cleaning and light construction of MCF area, only 2mW is allowed to come out from PSL room, we should increase the error signal by 250. We are planing to use the RF amplifier to emphasize the modulation sidebands and the RF PD signal. Actually the modulation depth is not large enough with a current modulation signal.