The aim of the shift to study the behaviour of the DRMI, with the arms controlled with the green laser in the CARM/DARM basis, close to the IR peak.
We first studied the DRMI locking sequence and see if there were any issues. So we first aligned it as described in : 51265.
We had to adjust the gains of the different DoF in order to achieve the DRMI lock today. So the current values are:
- MICH =4.0
- PRCL=0.18
- SRCL=0.55
Then using the automation we went through all the steps to control DRMI using 3f signals:
- Lock on 1f signals.
- Engage PR Tx and Ty drift controls.
- Engage PR in fullbandwidth.
- Hand off to 3f signals.
However in the last step we were unlocking the system every time we tried. See figure 1 for an example (~09:34 UTC). It seems to be related to an overwrite of input channels for the different DoF. Therefore we need to fix this soon. Diego and Alain are already informed about this cm_commands/automation issue.
Then after, we tried to align the Narm green beam, because it showed large misalignments. We acted on the galvos in order to reach enough power on the reflection signal and to optimize the 00/01 mode ratio. At the end we managed to obtain a quite enough good alignment (checking both the signals of reflection and transmission power, and the beam projections of the ALS_NE cam on Gxclient), but the north arm was keepin locking on HOM.
At the end we left SR and PR parked and the long cavities locked on IR.
