This log summarizes the Guardian modifications related to the commissioning work reported in klog37802 and klog37803.

[DOWN state]

Added the following command to reset the MICH1 filter gain: self.FILT_MICH1.ramp_gain(1, 1, False)

### MICH 1f/3f locking

[PREP_FM_FOR_MICH]

• Set the HWP angle (IFO_REFL) to 140 deg.

• Set the following demodulation phases:

  • REFL_PDA2_RF51: 85.1 deg

  • POP_PDA1_RF17: -141.00 deg

[ENGAGE_MICH_3F]

The Guardian sequence branches into MICH 1f and MICH 3f locking after this state.

• Set the MICH1 filter gain depending on the requested state:

  • MICH 1f: 1.8

  • MICH 3f: 5.2

• Explicitly set the MICH input matrix (INMTRX) according to the requested locking configuration:

  • MICH 1f: POPA17Q

  • MICH 3f: REFL51Q

  Although REFL51Q was already selected in the DOWN state, the input matrix selection is explicitly performed here.

• In klog37802, we reported that the FB8 (z1p0.1) filter had been disabled to stabilize the MICH lock. However, after adjusting the HWP angle, the lock became stable with this filter enabled. Therefore, FB8 remains enabled in this state.

[MICH_1F_LOCKED, MICH_3F_LOCKED]

• Commented out the @check_mich decorator.

### PRX 1f/3f locking

[PREP_FM_FOR_PRC]

• Set the HWP angle (IFO_REFL) to 140 deg.

• Set the following demodulation phases:

  • REFL_PDA2_RF135: 31.200 deg

  • POP_PDA1_RF45: 57.870 deg

[LOCKING_PRC_3F]

The Guardian sequence branches into PRX 1f and PRX 3f locking after this state.

• Set the PRCL1 filter gain to 1.4 when PRX_3F_LOCKED is requested.

[PRX_3F_LOCKED]

Modified the threshold monitoring channel used by the @check_prc3f decorator:

• Previous channel: POP_PDA2 (DC)-->>New channel: POP_PDA2_RF90

When PRC is locked with the 3f signal, the POP_PDA2 DC power decreases. Since the previous threshold was set to detect values above a certain level, it was not suitable for monitoring the PRC 3f lock.

Therefore, we decided to use POP_PDA2_RF90 instead.

### PRMI locking

[PREP_FM_FOR_PRMI]

Added the demodulation phase settings optimized during the MICH and PRX commissioning:

• ezca['LSC-REFL_PDA2_RF51_PHASE_R'] = 85.1    # MICH 3f
• ezca['LSC-POP_PDA1_RF17_PHASE_R'] = -141.00   # MICH 1f
• ezca['LSC-REFL_PDA2_RF135_PHASE_R'] = 31.200  # PRCL 3f
• ezca['LSC-POP_PDA1_RF45_PHASE_R'] = 57.870    # PRCL 1f

These settings have not yet been tested for PRMI locking. If they are found to be inappropriate, please comment out these lines.