1. ALS sensing noise measurement with the best conditon so far.
Since we improved the damping of PR2, we now know ALS noise gets better if we turn off all the PACs for PSL room, and the seismic motion is relatively quiet today, I measured the spectra of open loop (out of loop) stability of ALS.
This is the result. Black trace shows the one we took the end of the last year, and red shows the one we took today, with better damping of PR2, and all the PACs off.
The RMS of the ALS sensing noise times cavity LPF is less than 8 Hz this time!

2. Demonstration of lock acquisition sequence of X arm using ALS
How the power in the arm builds up.