Stefan, Kiwamu, Sheila

We have locked ALS DIFF with a bandwidth around 10Hz. The first 3 attachments are some screen shots of the configuration we had tonight when locking ALS COMM and DIFF.  The ALS DIFF guardian enforces some of these settings, it doesn't control the drivealign matrices or the ESD offsets.

To get this we moved the UIM/test mass blend down to take care of the 10Hz UIM saturations, added an additional high pass to the UIM to reduce the low frequency drive, then pushed our UGF to around 10Hz.  We added three low frequency boosts to DARM, after that we were approaching the VCO noise that Stefan measured earlier using a IFR in place of the DIFF PD.  We added the FDD back in, which improved the noise at high frequencies. Spectra of the suspension drives are attached. 

We then locked ALS COMM on the side of the fringe, and adjusted the DARM offset to bring the IR roughly half way down the fringe on the Yarm.  The attached screen shot has both the ALS DIFF PLL control signal calibrated in Hz and the TRY PD roughly calibrated in Hz, with no frequency dependence (so this is not to be trusted above a few 10s of Hz). The strip tool shows the time series of this. 

Then we locked both arms on IR using just ALS.  The attached screenshot shows them locked and both roughly on resonance, we moved the COMM VCO set frequency by 500Hz to bring both arms off resonance, brought it back on resonance and off again.

Next we locked PRMI on the 1f signals, and adjusted the BS alignment which resulted in better IR alignment in the Y arm.  PRMI power build up was 80uW in POP18 at the highest, which is pretty good.

After this we went to ISCT1 and realigned the diff beat note, we see 18.5mV rms our of the BBPD now.  The attached screenshot shows the GigE cameras and the IFO align screen with this alignment. 

We then locked PRMI on 3f.  To do this we disconnected the power from the BBPD for Alexa's POP beat note measurement, and took the RF cable from the table to the rack back for 3f.  At the rack side Kiwamu took the cable routed to POP9 back to the 3f diplexer. 

We succeeded several times in locking both arms using ALS, moving them off resonance, locking PRMI on 1f.  We could transition to 3f signals, but PRMI was not very stable. 

The BS ISI has been tripped most of the night.