The task of this morning shift was to find two independent signals to control the shift and the tilt of the PR during the lock acquisition. The idea was to control the shift of the PR mirror with the B2 QPD2 quadrant signals and the tilt by using dithering lines to maximize the arm cavity power.

Unfortunately it was not possible to find both signals.

We have then decided to implement the fixed shift on the PR mirror at step 0.1. The amount of the shift has been evaluated by closing the tilt of the PR on the 0 of the B2 QPD2 signal and maximizing the power.

This procedure works fine and it will be implemented in Metatron, see Figure 1.