During the reboots I took the opportunity to have another look into the OAT RefCav in the optics lab.
I removed the 50/50 beam pslitter infront of the RF LSC diode, so now ~30 mW of power is incident. In addition in optimised the HWP infront of the PM to reduce the AM, 2f_sb = < -80dB.
The few irises in the beam path are closed down, I looked with the viewer and reduced the iris so it was just not clipping.
I didn't find a low enough ND filter to o the paracitic interfernce hunt.
The cavity locks stable with a UGF ~300kHz, the settings are
Coarse | Fine | Common | Fast | Offset |
351 | 420 | 350 | 540 | 293 |
The Laser temperature on the controller displays: T+40.991, the slow output (T-ed to the laser slow input and the oscilloscope) is at -620 mV.
Once we get the cavity locked again we can see if we gained anything.