We got some AS72 results today with the IFO at Nominal Low Noise (NLN). 

First, as a sanity check we dithered the OM1 in pitch and then looked at the AS72 MHz response. If the PLL is perfect, all the spot position signal should be in the I phase, while the PLL residual will rotate the I phase signal into the Q phase. We varied the overall loop gain by factor of 10 and the largest I/Q ratio was 2.5 (~40% spot centering leaking into Q phase). Adjusting the phase of each quadrant did not noticeably improve nor degrade the PLL performance so we just put them back to zero. 

Then we measured a sensing matrix at NLN

It seemed possible to form a non-degenerate 2x2 matrix for SRM/BS alignment using RF72_A_Q/RF72_B_Q according to the measurement. This means that if in the future we can sync the phases of 118.3MHz and 45.5MHz without needing a secondary demod loop, we can then decouple the wavefront distortion from DC spot centering: even the OMs locked with offset, the BS/SRM alignment signal should not be contaminated by the mis-centering. Alternatively, we can also use the AS72_A/B_I signals for RF centering (AS_A_RF72_I -> OM2, AS_B_RF72_I -> OM1) to avoid carrier junk lights. 

An earthquake came in shortly after we finished the measurements so more measurements under different TCS settings will be preformed tomorrow. 

Sheila, TVo

We measured the ITMY ISI RX motion to DARM using different Bias Voltages and found that there was no change in the coupling when going from +380 Volts to -380 Volts with a few increments in between.

Then we tried to move the vertical position of the optic by changing the offset in M0_DAMP in increments up to 73.36 micrometers and there was no appreciable change in DARM as well.  It is possible that we didn't move far enough to induce a change, but we also didn't want to break lock.

These null measurements could indicate that the ISI-to-Darm coupling is caused by image charges, which do not depend on the bias voltage.  This particular type of noise cannot be fixed by unplugging the ESD since the interaction is between the test mass charge and the suspension cage image charge, however, the TMDS would be able to make a difference.

The DTT template is in /ligo/home/thomas.vo/LIGO/ISC

Here is a measurement of the DARM OLGTF for tonight, with the blue being a recent reference and the red tonight's measurement.  This is after discharging ETMY.  With the discharging kappa tst dropped from about 1.09 to 1.05. 

Starting Aug29, took elevation readings of the short HEPI Piers at HAMs 2 & 3; just the far outer corner of the pier as best I could put a ruler rod.  Also shot a few spots on the slab at the PSL Enclosure.

* The difference in the HAM2 and HAM3 average elevations is within 0.2mm of the design heights based on the LIGO Global Frame wrt local gravity.  The grout plates on which these piers reside would have been positioned in 1998 or '99!

* The HAM3 elevations have a runout of just 0.15mm; that is, deviation from the average.

* The HAM2 runout is 0.9mm.

* These runouts are seen as a potato chip or pringle as opposed to a simple tilt; see page 2 of attached notes.

* The PSL readings are a starting baseline, there is nothing previous to compare.

After we vent the vertex, I'll repeat these measurements to look for floor tilt in response.

Attached are my surveying notes.

TITLE: 09/08 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: Peter realigned the reference cavity. Dave restarted daqd to address an nds issue. TVo took charge measurements. Cheryl, Ed and Gerardo completed WP 7144. Cheryl helped me diagnose the alignment of the ALS Y arm (kept losing lock after engaging the WFS). Sheila and TVo have just brought the IFO to NLN.
LOG:

Peter realigned the reference cavity before the start of my shift.

Came in to aftershock of 8.1 mag. earthquake in Mexico.

15:07 UTC Peter out of optics lab (in before start of shift).
15:11 UTC Jeff B. to LVEA to take particle count measurements.

All of the DTT FOMS have stopped. Seems there is a nds1 issue.

15:21 UTC Changed MC2 from misaligned to aligned and then something set it back to misaligned. Turns out it was because the HAMs were in the DAMPED state instead of the ISOLATED state.

15:25 UTC Jeff B. back.

Hit Init for ISC_LOCK guardian.

15:27 UTC Set ISI config to WINDY, then back to LARGE_EQ_NOBRSXY.
15:35 UTC Jim bringing chambers from DAMPED to ISOLATED.

Jim changed ISI config to WINDY.

TVo working on charge measurements. Cheryl trending channels for WP 7124.

Dave restarted daqd to address nds issue.

16:37 UTC Cheryl to optics lab to get IR viewer.
16:43 UTC Hugh to LVEA to look for equipment.

Cheryl created new work permit 7144 to replace 7124 (may need to remove lexan cover). Approved remotely by John.

17:04 UTC Cheryl transitioning LVEA to laser hazard.
17:15 UTC Hugh back.
17:16 UTC Filiberto taking equipment into squeezer bay.
17:17 UTC LVEA is laser hazard. Cheryl, Ed and Gerardo starting WP 7144 (viewport on HAM2).
17:32 UTC Richard testing access cards at entrance to LVEA.
17:48 UTC Richard done.
17:58 UTC TVo done charge measurement.
17:59 UTC TVo to LVEA to look for viewport covers.
18:19 UTC Filiberto back.
18:21 UTC Cheryl, Ed and Gerardo done. Transitioning LVEA to laser SAFE.
18:24 UTC Ed back.
18:30 UTC LVEA is laser safe.
18:39 UTC Starting initial alignment.
18:46 UTC Betsy, Bubba, Gerardo to LVEA.
19:14 UTC Betsy, Bubba and Gerardo back.
19:43 UTC Set ISI config to SC_OFF_NOBRSXY. Jim to biergarten to lock compact BRS in prep for move.
20:38 UTC Jim done. Setting ISI config back to WINDY.
22:43 UTC Dick to CER to retrieve equipment.

If you log into a workstation using the controls account, you may notice that the ESC key on your keyboard is mapped to be a second CAPS LOCK key. We don't know why this was done.

For 'vi' users this poses a problem, as ESC is the way to get out of INSERT mode.

I have implemented a solution, which is more fully explained in my VimEditor wiki page . It maps the key sequence 'j' + 'k' (typed rapidly) to exit out of INSERT mode. For 'power vi' users this is a good habit to get into, allowing you to edit more quickly without having to move all the way over to the ESC key.

Of course ideally users of the controls account (or any shared account) should refrain from remapping keys :)

while testing a workstation I happened to plot a minute trend of H1:PEM-EX_ACC_EBAY_FLOOR_Z_DQ. It shows a loss of signal around noon local time today. Fil says he'll take a look at this.

This afternoon I went to try to lock up the cBRS in the LVEA, and it didn't go well. When I went to pull the bell jar off, I bumped the upper arm, which immediately broke the copper flexures. I've let UW know, and have otherwise finished disconnecting and, with TVo's help, moved the BRS next to the east side of the H2 HAM3 chamber, behind a sus storage box. Hopefully it will be safe there, if I stay away from it.

1. Matching the gain of each quadrant:

When we reached DRMI locked last night, we adjusted the gain of each AS72 WFS quadrant s.t. the 205 Hz line after the first demod all having roughly the same amplitude. 

2. Adjusting the phase:

We drove SRM in length at 4Hz last night from 04:40:00 to 04:47:00, Sep 08, 2017 (UTC). Then offline we computed the transfer function from AS_AorB_RF72_I1_DEMOD_I to AS_AorB_RF72_Ij_DEMOD_I at 4Hz. Each quadrant's phase is then adjusted to compensate for the tf phase. For future reference, the tf phase were:

3. 118MHz mod depth measurement:

We also use the driven line to measure 118MHz SB's mod depth relative to 9MHz. 

where in the opt. gain, the 0.5 accounts for that the AS72 has one more demod (half of the signal lost at 2xf_dmd), 10 for 118MHz DRMI transmission relative to 9MH (assuming dithering SRM in length only changes 45MHz and 9/118 serves as a static reference field); the PD resp was from T1300488; the final cnts had a bw of 1/256 sec. 

We thus have gamma_9/gamma_118 ~ 1, 600, consistent with what Kiwamu measured in 37061.

Attached are the long-term trends of Bias Voltage and Actuation Strength for ETMY taken today.

It looks like there was a big shift compared to August 31st, this  could be due to a combination of the TMDS work and the 8.0 magnitude earthquake. 

This morning I adjusted the alignment into the reference cavity.  Mostly vertical adjustments on
the periscope were done.  When I started the reference cavity transmission was ~0.6V, afterwards
~3.56V.

    Measured the open loop transfer function.  Originally with the common gain slider at 16 dB.
After the measurement I changed this to 18 dB to sit at the peak of phase bump.  As I was measuring
the transfer function at 18 dB, a glitch of some sort occurred which resulted in a loss of 2 dB
in the unity gain frequency and not sitting on the peak of the phase bubble.  Coincident with the
glitch I noticed that the Pockels cell monitor saturated, perhaps caused by the input modecleaner
trying to acquire?

    The difference in the common gain is not much.  It might be better to return to 16 dB if 18 dB
is problematic for some reason.

Attached are some images of the old and new scheme for holding the calcite polarisers
in the output Faraday isolator.  A fit check was executed - with the old scratched up
polarisers.  Everything fits just fine.

Sheila, Thomas Vo, Hang Yu,

There was a magnitude 8 EQ off the coast of Mexico tonight.  We went into LARGE_EQ_NOBRSXY on the seismic configuration node after the first waves hit, but all the ISIs tripped anyway.  We were able to keep most of the quads damped most of the time, although ITMY was tripped for a little bit.  LLO called and we set the WD thresholds up to allow us to bring the ISIs to damped after talking with them. This helped to stop the optics from swinging so much.  A few minutes after we got everything damped, a few more ISIs tripped.  

The attached screenshot shows a comparison of the ETMX  STS during this EQ to the Montana one July 5th.  The STS was saturated tonight. 

We quickly checked that all four quads moved when we applied offsets to the top mass. Although ITMY only moved 2 urad for a 10 urad offset, I think this could be a calibration issue with the alignment slider. We left all ISIs‌ and suspensions damped for the night, with all HPIs isolated.  

Attached is a  trend of the PSL status in the past 60 days, it seems like the FSS_TPD is slowly diminishing over time and needs to be looked at.  We think this is the reason why we had trouble locking in aLOG-38568 and the reason why we had to increase the FSS gain by +6dB.

Sheila, Hang, Patrick, TVo

The ALS was particularly noisy tonight so the ISC_LOCK guardian had trouble finding IR on the Y-ARM.  To get around this, we had to manually shift the ALS-DIFF OFFSET to get some resonant flashing.

We saw that the Diffracted Power % in the ISS was too low and adjusted the ISS Second Loop following the instructions of aLOG-31245 and saw that the IMC would not stay locked when turning on the second loop.  After this procedure, the IMC wouldn't stay locked for more than 5 minutes at a time until Sheila added 6dB to the PSL-FSS_COMMON_GAIN and now it seems to be more stable. 

Hang was able to lock DRMI_1f for his 72 MHz measurements after the change in the common gain but an 8.0 Earthquake off the coast of Meixco broke the lock.

Sheila and I had similar problems, we weren't able to get the realtime graph to come up while connnected to h1nds1 server.  Not sure if this is a temporary problem...

The DAQ uptime on the CDS overview screen for h1nds1 is not going up, h1nds0 still works.