[Gabriele, Sheila]

We did a quick test to see how big an offset we can add to the SRCL loop in DRMI, before losing lock or seeing mode hopping. The test happened between 20:36 and 20:51 UTC, causing several lock losses.

We could go as far as -3000 and +1000 in SRCL input offset uncalibrated units.

The plot below shows how POP_90 and POP_18 change with the offset. As expected, POP_18 do not change much, while POP_90 shows a clear parabolic shape (fit included). The minimum is at an offset of -680 counts, very close to the offset that we are currently using (-800 counts). The SRCL offset in the plot is calibrated using the number from 14550.

Note: the last two attached plots differ only for the X axis: one is in SRCL error signal offset units, the other is in SRCL physical offset on nm