TITLE: 01/23 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: None
SHIFT SUMMARY: Commissioning continues. Currently locked for almost 4 hours.
LOG:

1530 Chris S to and from EY supply fan room
1625 Karen to Opt. Lab
1650 Karen out
1653 Peter to Opt. Lab
1658 Nutsinee to ISCT6
1919 Nutsinee out
1944 Nutsinee to ISCT6
2001 Karen Rolling up the OSB receiving door
2006 Nutsinee out
2200 Nutsinee to ISCT6
2303 Chris done for the day
2321 Kyle to MY
2333 Kara to EY VEA
2335 Nutsinee out

2357 Kyle back

FAMIS10493

No water was added to either chiller, both were full and checked yesterday. Filter looked to be free of debris.

FAMIS8088

ITMY ST2 V3 is reported as high. Seems that it is elevated above the others.

I spent more time looking at the HAM3 ISI yesterday, trying to figure out the source of the 1.1 hz peak. I don't have a fix, or even an improvement, but I think the V2 GS13 is probably bad.

The top plots on my first two attached images compare the HAM3 & 4 HEPI L4C Z to local ISI GS13 asd ratios and transfer functions, HAM3 in the first image, HAM4 for the second. For all of these plots, both ISI's were damped only, so only the GS13s were in loop at the time. For both chambers, it's hard to see, but the HEPI Z to ISI V1/V2/V3 GS13 asd ratios lie right on top of the equivalent transfer functions. If I remember what Jeff said right, this means there are no significant non-linear cross-couplings in the GS13s. Note, also that the HAM4 tfs all look about the same, but V2 for HAM3 has a lower Q and generally doesn't look quite as similar to the other two HAM3 sensors, just like Keita found a couple months ago.

The bottom plot for the first two images are asds for the HAM3 and HAM4 local GS13s.  The gold line on each lower plot is actually 3 lines, the asds for each of the individual GS13s on the table are very similar over this frequency range. The light blue, dark blue and green (?) traces are are the residual asds after using MCCS2 in Matlab to  subtract all the coherent HEPI Z noise from each GS13. For HAM4, the residuals for all 3 GS13s look pretty similar, but for HAM3 there is quite a bit of extra noise in the residual for the V2 sensor below 1 hz. I'm not sure where it's coming from, but I could believe that it's something like the mass in the seismometer is a little sticky, or there's something wrong with the flexures. 

The third and fourth images are similar to the first two, but use the local CPS on HAM3 & 4 instead of the GS13s. The top plots on these images are similar to the first two, the asd ratios mostly lie right on top of the transfer, though match up is not quite as good at 1hz. I think this is probably because the ISIs, GS13s and L4Cs all have modes around 1 hz, there's a lot of stuff happening there.

The bottom plots on the third and fourth images are again the MCCS2 coherent subtraction of the HEPI L4Cs from the ISI local V1/V2/V3 CPS. Again, HAM4 all of the sensors asds and residuals all look pretty similar and the asds for the HAM3 sensors all look the same, but the residuals for the V2 sensor show more noise below 1 hz. I think this is because the damping loops are impressing the extra noise from the V2 GS13 on the V2 CPS. I plan on repeating this measurement for a period when the all of the controls are off, to see if the V2 CPS residual changes.

Some other tests I tried, but generally didn't keep good spectra of:

Moving sensor correction to HAM3 HEPI - no change to the 1.1hz peak, but good isolation at the microseism. Adding an IPS & L4C blend to the HEPI Z loop also didn't improve the peak, but the HEPI Z loop is, I think, only 2 hz ugf, maybe the gain of the Z loop can be pushed up.

Pushing RX/RY/Z blends around, this affects the frequency of the peak some, but doesn't improve the height much.

Turning off the ISI Z loop makes the peak go away. If the 1-10hz Z motion isn't that important, maybe we could run this way. Worth looking at more.

Running the Z isolation loop with just the V1 & V3 GS13s. Again, no improvement, but 4 out of the 5 remaining loops still use the V2 sensor. The contribution is small for the X/Y loops, but RX and RY need the V2 GS13. This is worth looking at a bit more, Brian Lantz has a DCC document about why we shouldn't remove the sensor completely.

• IFO has been at 30W for ~2 hours, so I'm immediately starting LOWNOISE_ASC, stepping through.
  • Waiting a few minutes between each step, so far it seems okay.
  • I'm using DHARD_P FM4, the less aggressive cutoff.  However, I skipped a line earlier where DHARD_P FM1, the more aggressive LP, would have been engaged.  I'm not sure if this line was commented out when they were trying things in alog 46556.  If not, then perhaps the 1Hz ring-up was again just due to FM1.
    • After a few minutes, I noticed a 0.011 Hz ring-up starting, so I have turned off the DHARD_P cutoff.  That seems to have stopped the oscillation. (Yes, a period of just under 100 sec).
  • Trying CHARD_Y FM3 (less aggressive 10Hz lowpass) rather than the FM2 (sharper 10Hz cutoff) that is in the guardian.  There is a note commenting out FM3 in favor of FM2, saying that FM3 killed the lock, but FM3 should be gentler around the UGF of CHARD_Y, and the same amount of isolation above 20Hz (less isolation in the 10-20Hz band is the price we pay.)
    • Seems fine.  May not have needed to do this, but it shouldn't hurt.
  • Engaging DHARD_Y lowpass (FM2) seems to have given the arm soft Yaw dither loops a kick, which is then also seen by SRC1_Y and PRC2_Y.  (Immediately before engaging DHARD_Y FM2, I had also engaged lowpasses on the SOFT_P loops, but this kick was really only in yaw, not at all in pitch, so I think it must be the DHARD_Y lowpass, not the CSOFT_P and DSOFT_P lowpasses.)
  • Lowering dither line amplitudes, and ADS_DOF gains seems fine.  The DEMOD_I gains (so, the amplitude of the error signals) for 2 of the yaw loops are increased to compensate for the lowering of the dither amplitudes, although the equivalent increase in all the other ADS error points is commented out.  These 2 loops that still do have a gain increase on the error signal got a pretty good sized kick, but again seem to have come back fine.
  • LOWNOISE_ASC state is now complete, done by hand, everything seems stable.  Only differences: No DHARD_P cutoff at all right now, and CHARD_Y using a less agressive lowpass. Both of these changes are in the LOWNOISE_ASC guardian state.
• Started measuring DHARD after LOWNOISE_ASC, but lost lock during my excitation around 1Hz. (Was zeroing the ADS DOF loop gains during my noise injections).
• While reacquiring, engaging ASC for full IFO, big osc at 1.1Hz.  SRC2 was hitting input limiter, which might have made situation worse?
  • Not the limiter's fault.  Next lock, watching state carefully, SRC2 (or MICH?) started to ring up slowly.
  • Next lock, doing ENGAGE_ASC_FOR_FULL_IFO by hand, and waiting for a long time for convergence, and it seemed okay.  Sheila notes that we should double check that everything is set properly in PREP_ASC, since we are now using DRMI ASC, and it has some different settings from full IFO ASC.
• Also, PR gain was reporting too small of a number when we were at full resonance.
  • Looks like the value that is being used is IM4_NSUM, which is now calibrated into Watts injected into vacuum, not mW on the PD. The model is somewhat confusing though.  Need to re-check what's going on in the model (which doesn't match what the screens are displaying, I think).  Then need to change the calib in PR_GAIN.
• Later lock, changes to LownoiseASC seemed good, although very slowly over time (maybe 20+ minutes later) 1.1 Hz is starting to ring up.  I increased the DHARD_P gain from -50 to -60, and that seems to be allowing the resonance to die down.  Why are we not able to suppress this HAM2 motion before it starts to bother the ASC???

I have been looking at the in-vacum violin modes at LHO for the first 8 harmonics and thought it could be useful to upload the frequencies here for current works on setting up the active dampers. 

The data used to identify these frequencies is the recent 15 hours long stretch of low noise detector state on the 3rd January at 04:00:00

Each harmonic has the 32 violin modes identified (with a couple of missing ones at the higher order harmonics). 8 split modes per suspension and 4 QUAD suspensions.

These frequencies will be added to the LHO violin mode table which also include the 'Historical data' of the violin mode harmonics before the May 2018 swap of the ETMX, ETMY and ITMX. Comparing new and old values shows that the non replaced ITMY has also changed its violin mode frequencies.

The next step will be to measure the new Q's of these violin modes and grouping violin modes of all harmonics per test mass without exciting the suspension, as done during O2. 

NOTE: On the LHO violin mode table above there is a comment on the MODE 6 filter for ETMY: ' this doesn't seem to damp well, is it really an ETMY mode?'

The reason for the apparent inefficiency of this filter is that there are at least 2 modes in that region, potentially 3 modes as shown next on a high resolution spectrum during the time when the filter was active (I think):

TITLE: 01/23 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    Wind: 10mph Gusts, 8mph 5min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.31 μm/s
QUICK SUMMARY: Jenne already working a locking interferometer. A few FOMs needed restarting, as usual. Microseism is staying down and wind is below 20mph.

Sheila Georgia Craig Koji

IMC board saturation:

We had trouble staying locked for more than 10-20 minutes after powering up today, which turned out to be because of saturations in the IMC common mode board.  The attached screenshot shows IMC-REFL_SERVO_SPLITMON (which is a beckhoff channel calibrated into volts right after the IMC boosts) hitting 10Vs, IMC-L hitting it's ADC limit fractions of a second later (which doesn't matter since it's not in loop).  Georgia and Craig are working on redistributing the analog gains to avoid this. 

BS ST2 isolation glitches causing DRMI locklosses:

We had some difficulty keeping DRMI locked after it acquired tonight.  We went through the next several guardian steps, and found that the big transient glitches that have been causing us a lot of grief are from engaging the beamsplitter ISI ST2 isolation.  Georgia saw a transient on the optical lever when the only thing that was happening was that the BS ISI was isolating.  It should be possible to recreate this without locking anything.  For now we have removed the BS ST2 isolation from the main guardian path.

DRMI ASC:

Georgia also found that we had DRMI locklosses when the SRCL mode hopping avoidance offset gets turned off in ZERO_3F offsets.  We decided to try engaging the DRMI ASC to avoid this, which was fairly easy.  We changed some of the filter states (PRC1 and PRC2) to match what we are using in full lock, changed the SRM sensor to AS A 72Q (it was a combination of A+B), and increased the gains in several of the loops.  Once we had all the loops engaged Georgia tuned the POP A offset to increase the POP18 build up to ~63 counts.  We have tested the engagement with the gaurdian twice, it seems fine.

Lownoise ASC:

We tried to go through lownoise ASC once, but lost lock due to the IMC saturation, not related to the ASC changes we were making.  I've edited the gaurdian to not reduced the DHARD P gain anymore, and to engage the less aggresive DHARD low pass based on the measurement that Craig and Koji made last night (46559), this hasn't been tested yet.

After discovering that CW injections died on January 18 at 22:31:22 UTC (14:31 PST), for unknown reasons, I have manually restarted the injections at 04:18:50 UTC on January 23 on h1hwinj1. The injections are visible again (see screenshot).

Keita, Dave:

A reminder that the Dolphin cable was disconnected from h1psl0 in Oct 2018, back when the Dolphin network was not stable. The PSL-ISS model uses Dolphin IPC to receive the 3rd loop photo-diode signals from both ends, and the PSL-DBB model sends its jitter signal to the LSC. I had notched out these continuous Dolphin receive errors from CDS-Overview and the IPC-Overview, it is still visible on the GDS-TP screens. It is good practice after maintenance to check only the expected channels are in error (see attached).

WP8051 PEMCS, remove HAM6_SEPTUM ADC chan from generic list

Dave:

To fix the ADC-MEDM label for adc5_20 to show it is HAM6VAC_SEPTUM, h1pemcs was restarted. DAQ restart was required.

h1seiproc, latest model

Jim W

ODC removal

Keita, Jeff, Jenne:

ODC changes were made to: h1tcscs, h1lsc, h1omc, h1ascimc, h1asc, h1alsex, h1pemex, h1iscex, h1alsey, h1pemey, h1iscey. DAQ restart was required.

WP 8059 LSC Add POP_A_LF_IN1

Jenne:

new h1lsc model started, DAQ restart needed.

WP8054 Cal bug fixes

Jeff K

New h1calcs model was started, DAQ restart needed.

Slow Controls Beckhoff

Daniel, Dave:

PLC changes made to h1ecatc1plc[2,4]. New DAQ INI file generated. DAQ restart required.

DAQ GDS Broadcaster

Dave:

H1BROADCAST.ini was changed and loaded twice today. First change was to remove channels which had been removed from models beforehand. Second change was to remove the ODC channels which had been removed this morning, and add the timing FPGA and IRIGB channels back with their new names.

Restart Log:

• 2019_01_22 11:35 h1pemcs
• 2019_01_22 11:35 h1seiproc
• 2019_01_22 11:35 h1tcscs
• 2019_01_22 11:36 h1lsc
• 2019_01_22 11:36 h1omc
• 2019_01_22 11:38 h1ascimc
• 2019_01_22 11:38 h1asc
• 2019_01_22 11:40 h1alsex
• 2019_01_22 11:40 h1iscex
• 2019_01_22 11:40 h1pemex
• 2019_01_22 11:42 h1alsey
• 2019_01_22 11:42 h1iscey
• 2019_01_22 11:42 h1pemey
• 2019_01_22 11:43 DAQ RESTART
• 2019_01_22 12:46 h1calcs
• 2019_01_22 14:11 DAQ RESTART

From alog46181 and alog46446 it almost seems like this Mephisto mode hop region was slowly creeping upon us since holiday (probably has been since the beginning since we ran away from 27.6 degC alog45519 which is now no longer a good region to operate). Today I finally found a setting where we can go from mode hop to mode hop and operate in the middle. We are how sitting ~0.1A away from mode hoping region. Using 2.4MHz/mA (I re-calibrated the current -> Hz with more data point) we now have +/- 240 MHz of wiggle room. Temperature doesn't appear to be affecting mode hoping as strongly as current does so I'm going to neglect that for now.

For a future reference, here's what I did:

I scanned the SHG to look at the multi mode peak (looking at transmission) and look at RF spectral analyzer to ensure that I had the beat note. I tried to go down in temperature but to compensate and keep the beat note at the same place I had to crank up the current, which I quickly ran into clamp current value (2.25A). Terry suggested I go up in temperature instead and hopefully the current wouldn't have to go so low to compensate while having a nice mode-hop free region to operate. I turned up the temperature by a degree, and sweep current left and right to see if there's any beat note. At 31.5 deg C region I was still limited by the clamp current and soon ran into another mode-hop region. I somehow skipped 32.5 deg C (or maybe I just couldn't find the beat note) and found the beat note at 33.6 deg C region (as plotted). I alternate between temperature and current to keep the beat note roughly at the same place (158 MHz +/-). I weren't patient enough to wait until the temperature really settle down before I write these frequencies down (so an uncertainty of +/- 1-2 MHz is possible).

Both of these QPDs acquired an NSUM channel. The medm screens reached from the IMC overview have been updated to also include the whitening.

The calibration is now according to alog 46482. The segments are in mW, whereas the new NSUM channels is in W incident to the mirror.

The IMC trigger had to be adjusted to account for the change in the MC2 TRANS SUM.

Koji, Craig

Tonight we investigated intensity noise further.  We locked the OMC on just the 45 MHz at 30 watts with 18 dB whitening gain, and then locked it on carrier at 20 W with 0 dB whitening gain.  This is a repeat of here.

We found that carrier and 45 MHz noise levels are similar.  (See attachment one, carrier RIN is Blue, 45 MHz RIN is Brown)

We were confused about why 100 and 1000 Hz the carrier noise is lower.  We believe that this is mostly a shot noise effect.  
For 45 MHz we have 0.5 mA on the OMC DCPDs, while for carrier we had 34.3 mA.  This corresponds to RIN shot noise levels of 2.5 × 10-8 1/rtHz and 3.1 × 10-9 1/rtHz.
- The carrier is mostly limited by the ISS second loop sensing noise, as seen from the green curve in attachment one.  
- The 45 MHz flattens out right around our shot noise limit around 100 Hz.
- Both carrier and 45 MHz have similar RIN spectra below 100 Hz.

Recap:
We know that the 9 MHz modulation depth has a real effect on the DARM noise, seen here as well.  During the holiday party we were able to improve DARM noise by increasing the DARM offset, which could be due to increased carrier drowning out the 9 MHz noise.
We also know that our OMC measured RIN in the sidebands cannot be explained from the noise in our RF AM stabilization scheme, or the ISS.
We are pretty sure that the IMC FSR is reasonably close to our 1f modulation frequency.

Conclusions:
We here note that our shot noise from the OMC sideband measurements is not good enough from 80 Hz onwards to be able to tell what our actual 45 MHz sideband RIN noise level is.  
Below 100 Hz, carrier and 45 MHz RIN seem to be limited by the same mechanism, we don't know what it is.  
9 MHz is not ever limited by shot noise in the OMC RIN measurement, and is overall worse than both carrier and 45 MHz RIN after 20 Hz, where it starts falling much more slowly. (Attachment three)

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Past OMC carrier RIN measurement