Sheila, Jenne, Gabriele, Craig, Hang

We moved the input beam to the POP_A QPD (the ASC one, PRM->PR2->POP_A) by moving the IM4, while compensating the alignment to XARM by moving PR2. The motivation is that we have not changed the alignment to POP_A since O2 and it may thus serve as a reference point for our alignment.

After the input beam centered onto the POP_A QPD, we then moved the ITMY with a combination of green WFS & human servo actuating on the ETMY and TMSY to move the YARM axis overlapping with the input. We also moved the on table alignment to keep the ALS COMM beatnote ~ -2 dBm, and ALS DIFF ~ -14 dBm.

In the Guardian, we modified the ALS green alignment setup so that both ETM and TMS are actively controlled during lock acquisition  ('NO_SLOW_W_GR_WFS').

We now have ALS + PRMI locked with the input beam also on the POP_A.

HAM4 actuators are tripping pretty about every 10 minutes for the last hour or so. While there are people in the LVEA it seems unlikely to be related.   Attached is a plot of one of the trips. 

In the second attachment you can see that something seems to have broken around 6 am this morning (around 13 UTC July 27th).  There is a narrow line at 54.0 Hz  (3rd attachment).  

The last attachment shows that the 54Hz line doesn't show up now that the platform is damping. 

TITLE: 07/27 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: None
SHIFT SUMMARY:
LOG:

14:50 Jeff B out to LVEA to take pictures

15:43 Vanessa out to LVEA

15:46 attempting initial alignment

16:00 TJ shuttering ALS-X and turning off ITMX oplev to get a look at CO2-X situation

16:20 Shutters back open and oplev back on - Green alignment is good

16:28 TJ going back out to LVEA to close shutter again - ALS-Y at TJ's request

16:45 Tour group in CR

17:03 ALS-Y shutter back to OPEN

17:06 Jeff B back

17:51 Marc out to MY

18:27 Evan taking a couple out to LVEA for a tour

18:58 Evan and co back

19:33 Patrick and Fil out to CER to troubleshoot OPO Beckhoff

19:34 Sheila out to LVEA - ISCT1

19:49 Patrick and Fil back

20:07 Haocun out to LVEA-SQZ table

20:57 Sheila and Craig back

21:02 Georgia and TJ out to HWS table

21:02 Dave out to ISCT1 workstation

22:00 TJ and Georgia back

22:06 Craig out to LVEA

22:14 TJ and Georgia out to LVEA

22:25 Dave and Jonathan taking workstation back out to ISCT1

22:32 TJ and Georgia back

22:37 Jonathan and Dave back

Yesterday, Sheila and I gathered the information on the measurements of seed mode (see 43084), and got the conclusion that the seed waist is 556um at 3m before the upper periscope mirror.

Then I measured the beam mode profile coming out from the LO fiber coupler, which is divergent with waist 188um at 1.12m before the fiber coupler (Beam fitting as attached.)

If the estimation from the measurements is good enough, a potential mode matching solution is shown as below (I hereby copied the layout and labels from LLO):

• UPM/LPM = Upper/Lower Periscope Mirror
• L0: FL = 0.667m
• L12: FL = 0.445m; L13: FL = -0.334m
• L14/15: ROC = +50; FL = 0.1112m (already installed before, info from label)
• Positions of M13,14,15,16 and BS are only illustration, not precise positions yet. These can be adjusted according to the space on table, and will be updated later.
• The x-axis is in meter. 

For future use, I attached the alm matlab code of the mode matching solutions that can reproduce the graphs. 

• The UPM is at 3m, and the fiber coupler is at 1.2m, these are fixed points to start. (The 0 is tricky due to some restrictions of the code.) 
• Please follow the relative positions after the UPM and fiber coupler.

I will begin to install lenses and place them to rough positions without the seed beam.

I found that the Homodyne filters have already been added, including anti-whitening and calibration ones.

TITLE: 07/27 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    Wind: 4mph Gusts, 3mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.07 μm/s
QUICK SUMMARY:

Danny has a script running on ZOTWS9 that will run the ITM ring heaters with 3W of power for 30 minutes starting at 07:00 UTC.

Script is found at userapps/tcs/common/scripts/ring_heater_schedule_TJ.py

Note: the duration argument is in hours!

TITLE: 07/26 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: None
SHIFT SUMMARY:
LOG:

15:30 Started working on Green arm alignment

17:00 Patrick to EX  to take measurements

17:09 Daniel ad TJ out to HWS table

17:28 Kyle out to LVEA

17:46 TJ and Daniel back

17:46 Sheila and Haocun out to LVEA to take measurements

18:00 Sheila and Haocun back

18:01 Mark and Tyler out to EX to retrieve a valve on the floor under the BSC

18:03 Patrick back

18:08 Marc and Fil out to MY

18:09 Dave out to CER

18:25 Marc and Fil back

18:29 Jenne ad Hang out to ISC rack in LVEA

18:30 Sheila out to LVEA w/Jenne and Hang

18:51 Dave back

19:54 Lockloss at ALS Diff - it had been there for about an hour

20:08 Haocun out to LVEA

21:03 Sheila Craig and DS out to LVEA-ISC racks

21:23 Cheryl out to PSL ante room to retrieve EOM

21:30 Kyls out to LVEA to close a few NEG isolation valves WP #7734

21:40 Jenne, Craig and DS back.

22:28 Kyle back

Kyle, Gerardo

We don't like how flat the pressure has been at the corner station since being combined with the arms following the post O2 in-chamber de-install/install activities.  As such, I confirmed that the Vent/Purge valves were fully closed.  Today, the NEG1, NEG2 and NEG3 pumps were individually valved-out for 25 minutes or so each.  The responses are attached.  Next, we would like to verify that the 1 1/2" AMV pump port valves located atop the 2500 L/s ion pumps are fully closed and maybe repeat today's exercise with the 2500 L/s ion pump isolation valves.

[Commissioners]

Work still in progress, but we just locked ALS COMM and DIFF, moved them off resonance, and were able to acquire DRMI lock.  This is the first time for us since late 2017, so we're pretty happy!

Jim and I noticed this happening again...

Sheila, Hang, Jenne, Craig

We are still baffled by our low PRMI gains according to POPAIR_B.  We decided to do two OMC scans, one single bounce and one with PRMI locked, to get a second opinion of our PRMI alignment.

Results

Measured 45 MHz Power Recycling Gain ~ 30

Modeled 45 MHz Power Recycling Gain = 48

This seems to indicate something is weird with POPAIR_B and not our alignment.  Big if true.

Details
OMC facts can be found from Koji.  The most important fact for us is OMC FSR = 264.8 MHz.
Plot 1 shows our single bounce OMC scan, while plot 2 shows the PRMI locked scan.  We scanned the OMC by moving the PZT rail-to-rail at a constant rate over 200 seconds and read out OMC DCPD SUM milliamps.  Both plots are calibrated from time to frequency using the OMC FSR between the two largest peaks.  

The tall clean peaks in the first plot are carrier, with visible 9 and 45 MHz sidebands.  The sideband frequencies don't quite match up with peaks but our PZT isn't exactly linear so close enough.
The 45 MHz sideband appeared in the OMC DCPD with 0.03 mA.

The peaks in the PRMI locked scan are the 45 MHz sidebands.  
They are not balanced: 54% of the 45 MHz power is in the lower sideband:

PRMI Max OMC DCPD
-45 MHz = 0.79 mA
+45 MHz = 0.67 mA


Here we calculated the PRMI recycling gain from first principles.


where 
 

Then we estimated our current recycling gain from the measurement ratio of PRMI 45 MHz/singleBounce 45 MHz: 
For single bounce:  

Some cavity math: 

Yields:


Transmission Ratios:
PRMI -45 MHz/Single Bounce 45 MHz: 25.8351036066
PRMI +45 MHz/Single Bounce 45 MHz: 22.1094695082

PRMI Power Recycling Gains:
-45MHz = 33.36
+45MHz = 28.55

Craig, Sheila, Matt, Lisa

We went through an inital alignment and locked PRMI.  The build ups are about a factor of 3 lower than what we had in May, so we tried walking the alignment around a lot.  

For the initial alignment we had to do a few things:

• Removed decorator from ISC_library.OFFLOAD_ALIGNMENT_MANY.  This was not allowing the green WFS to be offloaded.  Since this is a state we don't want to redirect out of, I don't think we need the decorator there. 
• Flipped sign on PRC alignment loops (REFL 9 to PRM with PRX locked)
• Using the SR2 alignment that was found for centering on the OFI last night, I pico'd AS_C
• lowered the trigger threshold for SRY (which is triggered on LSC_POP)
• reduced SRY gain from 10,000 to 3,600 to avoid gain peaking
• flipped sign of SRC1 WFS (REFL 9 to SRM)

Once we saw that our build up was not good, we decided to try to bring the beam back onto the POP QPDs (We think that this path was not modified during the vent, we used to be on the QPDs and now we are too high).  We moved IM4 to center in pitch on POPA, and then moved the X arm to get the green and red co-aligned.  This resulted in worse build ups in PRMI. 

We can see something on the PR2 camera, which could be scatter but we can't be sure what it is.  We attempted to minimize the camera sum after Matt adjusted the mask to zoom in on these spots, but this also resulted in lower build ups.