TITLE: 02/19 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:

Shorter Maintenance Day to allow for more Commissioning time.  After Maintenance, performed an Initial Alignment + looked over Jenne/Nutsinee's shoulders as a Squeezer alignment was also performed.  Made it to NLN, with the help of Kara M., but it dropped out shortly after--Sheila noted a ~4Hz oscillation on an ETM---believe she mentioned this being related to dither align.  Regardless, she had me hover at LOWNOISE_ESD_ETMX on the order of 15min to let our locking signals stabilize before moving to NLN.
LOG:

• overnight:  Disk failure for fw0, related to LDAS (Richard notified CDS)
• Maintenance Vendors observed on site:  Carrier, Unifirst
• 15:58 - 18:20 TCSy CO2 mask install (Danny, TJ)
• 16:25 - 16:42 Checking picomotors inside h1psl (Peter K)
• 16:49 - 17:51 ITMx, ITMy Oplev centering (Ed)
• 16:50 MY annulus ion pump (Gerardo)
  • 22:52 Went back out to check up on it
• 17:05 18:20 ETMx+y charge measurements (Betsy)
• 17:08-17:31 Karen to MY
• 17:40 Searching for accelerometers (Kara)
• 18:25-18:38 Swapping OMC power supply (Fil)
• Officially ended Maintenance around 10:30amPDT (18:30UTC)
• 0:02  Got update on the failed FW0 from David.  Keeping work permit open for when this will get replaced.

TJ, Danny

Before installing the point absober mask:

• Final check on how the orientation of the installed mask gets projected on the compensation plate
  • To do this we inserted a shim to cover the diamond aperture (please see first attached figure)
  • It appears that the suggested HWS orientation in alog 46918 is correct. 
• We changed the angle of incidence into the poker mask so the reflected beam could be properly dumped (please see second attached figure). 
• Attempted to increase the signal to noise of the CO2 heating through the poker mask by increasing input power to 3 watts (see third figure). 

Installing the point absorber mask: 

• We installed the mask as shown on the left of the fourth attached figure.
• We didn't have much more time so we increased power only up to 1 watt for a few minutes with the point absorber mask in the path. (please see fifth attached image)

Next step:

• Analyze the optical path distortion with the compensation plate at a steady thermal state with 450 mW of CO2 power through the point absorber mask. 

Dan, Richard, Jonathan, Carlos, Dave:

FRS12353

h1fw0 is back online writing frames. Dan configured E18-0 POD-1 to rebuild its raid while it is being used by the frame writer.

Attached E18 log shows that the problem started at 21:16 PST Mon night, with a repeat at 21:29 and then a disk failure at 05:47 today, at which point I suspect the audible alarm sounded. Problem then became critical at 08:42 with a pod failure, and the frame writer stopped running at 08:44 (all times PST).

Attached E18 status screen shows POD-1 disk3 and disk2 are actively being rebuilt (green bar is animated growing left-to right), the other disks of POD1 are flashing green-yellow showing they belong to a degraded raid.

Frames gap on hfw0:

-rw-r--r-- 1 controls controls 1.6G Feb 19 08:46 /frames-0/frames/full/12346/H-H1_R-1234629632-64.gwf
-rw-r--r-- 1 controls controls 1.6G Feb 19 11:16 /frames-0/frames/full/12346/H-H1_R-1234629952-64.gwf
 

Betsy and Rahul

Betsy ran the charge measurements this morning for the ETMY and ETMX and later we performed the analysis on matlab. After finishing the measurements, we restored the alignment slider values (SDF) etc for lock acquisition. 
The plots of ETMY and ETMX are attached below. No considerable change is observed and it looks consistent with the previous measurements performed last week (or last few week). The long term trend also looks stable. 


P.S - Later we found that the bias voltage switch for the ETMX was switched OFF, not sure how this has happened. We checked the SDF while restoring the values, however it seems like we might have overlooked it. Jenne switched the bias voltage ON.
We will keep this in mind during the next charge measurement.

WP 8092

Unit was placed on a temporary HV power supply. This is part of the 180 Hz noise seen in DARM, alog 46839.

I re-centered ITMX and ITMY OpLevs not enough time for BS and end stations are currently unaccessible.

I restarted the primary and redundant calibration pipelines around GPS time 1234632718.  This restart picked up the new filters and configurations described in LHO aLOG 46984.  The pipelines are running normally, and so are the DMTDQ processes.  As expected, the latency decreased by a couple seconds.  The testing pipeline was restarted on h1dmt3 as well.

TITLE: 02/19 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: 3mph Gusts, 2mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.24 μm/s
QUICK SUMMARY:

Maintenance Day from 8-10am!

• Plowing around LVEA.
• FrameWriter0 (fw0) has a disk failure (i.e. this will be beeping heard around MSR).  Richard's notified CDS.
• Mask for TCSy CO2 has commenced with Danny & TJ.

Power line noise in DARM:

• We tried adding the ferrite toroid to the cable from the fast shutter controller to the OMC PZT driver as pictured here LLO 41394.  As Rich suggested I also unplugged the squeezer test equipment that was plugged into the AS racks, and powered down the picomotor controller on ISCT6 using the rocker switch in the back of the chassis.  None of this made a difference to the broad power line noise we have at around 60Hz, 120 Hz, and 180 Hz.  It also made no difference in the spectrum of OMC LSC I or the PZT HV AC monitor channels.  
• During an earthquake Craig and I went back to the rack and tried several configurations watching the PZT AC monitors as we moved the toroid around.  THE PZT2 monitor didn't change much for any of the configurations, the PZT3 monitor which has the most lines also had the most dramatic changes for different configurations.  In the end we left the toroid right on the shutter trigger input to the PZT driver, this reduced the 180 Hz line in the AC monitor (see second attached screenshot for the variety of noises in the PZT3 monitor)
• It seems like our problem is different from the one diagnosed at LLO in 41394 since we don't see any of these lines in the OMC LSC error signal. 

Offset on PZT3 (PZT1):

• Jenne and I locked the OMC with 50V applied to PZT3 (which is really PZT1) and 80V applied to PZT2, which should reduce the transmission of the 9MHz higher order mode through the OMC according to Koji's second attachment in: 46667 
• We injected 9MHz RFAM using RF AM stabilization box excitation.  Comparing the same transfer function with and without an offset on PZT3 there is a 20% improvement in the coupling of the 9MHz driver noise to DARM with the PZT offset on.  There is about a 20% reduction in the measured coupling from the RF AM driver AM monitor to the noise in DARM with the PZT offset.  Some of the reduction seems to be due to to a drift in the amount of 9MHz arriving at the AS port, if we measure the transfer function from the OMC QPD RIN to meters the PZT offset has reduced that coupling by about 15%.   In the lock with no offset on PZT3, I tried to move PZT3 around a bit but the coupling doesn't depend very sensitively on the position of the PZT.  It might be worth trying this with the 50V offset on PZT3 as well.  
• The time of the injection with no offset on PZT3 was 5:42:16 UTC Feb 19th, with 60V on PZT3 the time was 23:57:38 UTC Feb 18th. 
• Georgia also repeated the tests from 46831 with the PZT3 offset on, and off.

OMC ASC on dithers:

• While Georgia was changing the DARM offset, we noticed that the 100-400Hz BLRMS was responding to her change.  It turns out this was because this monitor was dominated by lines in DARM.
• We trned off the LSC dither lines which have been used as monitors since December, and removed them from the guardian.   We also widened nothces and adjusted the frequencies of some of them so that the 100-400 Hz blms is now measuring the level of broadband noise.
• The reason that the BLMS channel was responding to the DARM offset change was that the optical gain change is not completely compensated by the quadratic scaling done in the OMC model.  The optical gain was changing by 5% more than that scaling was compensating for. 
• We wondered if the change in the DARM offset (or the 9MHz modulation depth) was changing the lock point of the OMC ASC, which is still using QPDs.  Georgia tried adjusting the QPD offsets a little bit.
• The kappa c monitor seems not to be working, so we made two of our blms channels into narrow bandpasses for the pcal lines, and tried to use those as montiors for the optical gain, but they are rather noisy.
• I tried setting the OMC back on the dither alignment, which is working fine so far and not close to saturating the suspension.  I only moved to the dithers about 2 hours into the lock, so there may be a time earlier in the lock when we can't use them.  
• While the dithers moved the OMC alignment, they didn't improve the optical gain.  

4.5 Hz instability in DARM loop:

• We had one lockloss where the DARM loop seemed to go unstable at 4.5 Hz.  The pum cross over has a 0 phase margin around that frequency according to the model here, but we think that we should not have any cross overs there according to the model. 
• We made a quick measurement by injecting into ETMX L2 (attached screenshot), which agrees well with the model from 25-10 Hz. 
• We also looked at the drive spectrum of all three stages, and tried a small increase in the L2 LOCK gain, which did slightly reduce the RMS drive and reduced the small peak in the drive amplitudes around 4.5 Hz.  We have added this small gain change (15 to 17 Hz) in the guardian. 
• We lost lock once more with a similar 4.6 Hz instability in DARM, (with the gain of 17 in place) about 10 minutes into a lock.  I wonder if there is something about the ADS loops slowly converging that is having an impact on the DARM loop.  We may need to spend some more time on the stability of this crossover, next lock I just waited for the ADS to converge before transitioning the DARM actuator. 
• The guardian is now doing the switch from ETMY+ITMX to ETMX in one step, rather than two.  

I went through some of the ADS things in LOWNOISE ASC to try to make the ADS a little less confusing to me. 

• I set all the amplitudes to be the same (they were all within a factor of 2 or so of each other anyway). 
• For PIT3 and YAW3 we had a signal gain of 0.1 canceled by a demod I gain of 10, got rid of these two gains and added a filter module which will be engaged earlier engage soft loops to compensate for the higher signal gain and keep the loop gain the same as it has been. 
• For the other loops I also have found it confusing that the I gain was not the same as the Q gain, so I moved the compensation for the dither amplitude reduction into filters as well.  
• For PIT4+5, I also added additional gain, because these loops were taking a very long time to converge.  (Now PIT4+PIT5 have the same gains).
• For YAW4+5, I moved the gain into filter banks, decreasing the gain of YAW5 and increasing the gain of YAW4 so that they now match each other.  

We aso reduced the CSOFT P gain in lownoise ASC from 30 to 20 as Danny was doing yesterday, this is in the guardian now. 

We also set the DCPD NULL matrix elements to be the same as the sum matrix elements but with a sign flip.  Stefan had set them according to this procedure: 45734 but that isn't compatible with the online DCPD cross corelation calculation, so for the moment we are setting them back to see if we can get some good data for the cross corelation measurement.  We also found that there was a gain of 1.2 in the inverse sensing function, which we needed to copy for the null stream filter.  Now we are getting more sensible results from the cross correlation. 

All EX I/O chassis fans appear in DARM, and I have been using them as injections, along with other injections to investigate the voltage noise coupling to DARM. I have left for a couple of weeks so I wanted to enumerate changes that have not yet been undone (or made permanent).

1) Temporary ESD power supplies, HV, 48 and 18, have been set up just beside the field rack and grounded to both the rack and the beam tube.

2) The temporary power supply ground connection was moved from the field rack ground at the rear bottom of the field rack to the field rack chassis ground that is attached to the ground bar on the cable tray. This reduced the resistance between the ESD chassis and the power supply ground.

3) All IO chassis were grounded to the racks. This reduced the resistance between the IO chassis and the rack from very high values to less than 1 ohm.

Moving the ESD power supplies out to the field rack and grounding them in various ways did not change the coupling to DARM of the SEI, ISC, and SUS fans as well as temporary injections that affect the grounds. Also, I have not yet been able to find voltage differences, such as between the beam tube and the ESD shield ground, that have consistent coupling ratios to DARM for each of the different peaks (see figure) and so I cant yet predict the contribution of the broad band V noise to DARM.

[M. Wade, A. Viets]

I made a new GDS filters file to be installed tomorrow during maintenance.  The main change is an improvement in the high-pass filters and a reduction in latency.  The actuation filters were reduced in length from 6.0s (between 2 separate filters) to 3.5s (all one filter), which in theory should reduce the latency by 2.0s.  The following changes were made to the design of the high-pass filters:

• In the frequency domain, the filters roll off to zero faster.  They previously rolled off to zero from 8 Hz to DC, and now they roll off to zero from 9 Hz to 4.5 Hz, as they did in O2.  Unlike in O2, the filters are windowed in the time domain with a Kaiser window, rather than a Tukey window.  The choice of window makes all the (many orders of magnitude of) difference.
• The inverse sensing path is filtered with an additional high-pass filter at 2048 Hz.  This allows us to apply a longer high-pass filter without unmanageable computational cost.  The model filter is now 1.0s long, and the additional high-pass filter is 2.5s long, making the total filtering length equal in temporal duration to that of the actuation path.  How can this be done without losing information above 1kHz? 
  1. Spectrally invert the high-pass filter to make a low-pass filter with a gain of -1.
  2. Tee the inverse sensing path and downsample one copy.
  3. Apply the low-pass filter to the downsampled data.
  4. Upsample the low-passed data to 16384 Hz.
  5. Add the result, which only contains the content of h(t) below 9 Hz (times -1), to the original h(t).
  Then the model filter is applied at the full sample rate of 16384 Hz.  The model still includes a high-pass filter, in order to attenuate low-frequency noise as much as possible.

The filters file is in calibration SVN revision 6577 at this location:
trunk/Runs/ER14/GDSFilters/H1GDS_1234630818.npz

It was made using the script
trunk/Runs/ER14/H1/Scripts/TDfilters/H1_run_td_filters_1234630818.sh

The parameters file used was from the 2019-01-18 model:
trunk/Runs/O3/H1/params/modelparams_H1_20190118.py

The suggested configuration files for running this on the production and testing DMTs are:
trunk/Runs/ER14/GDSFilters/H1GDS_1234630818.ini
trunk/Runs/ER14/GDSFilters/H1GDS_1234630818_TEST.ini

The attached plots are:
1-2) Bode plots of the filters
3) ASD spectrum comparisons showing GDS-CALIB_STRAIN and GDS-CALIB_STRAIN_CLEAN.  Data was from 2019-01-30.
4-5) Comparisons of the frequency-domain model for the control corrections to the actual effect of the filters on the data.  Data was from 2019-01-30.
6-7) Comparisons of the frequency-domain model for the residual corrections to the actual effect of the filters on the data.  Data was from 2019-01-30.
8-9) Comparisons of the frequency-domain model for the response function and GDS-CALIB_STRAIN / DARM_ERR.  Data was from 2019-01-30.  Note the significant discrepancies.  One possible contributor is the fact that the front-end may not have been using this reference model during the time this data was taken from.  It is likely there are problems with the GDS correction filters as well.
10) A plot of the latency of the pipeline when reading from shared memory on ldas-pcdev1.ligo-wa.caltech.edu for ~4 minutes of data taken earlier today.  This does not include the 1.0s length of the frames.

[Sheila, Jenne]

Xarm's green transmission was looking glitchy, similar to how it looked last week.  So, I toggled its noise eater, and it seems to be okay for now. 

• First lock:
  • made it up to nominal low noise but lost lock due to what appears to be CSOFT pitch (please see first attached figure).
  • right before the lockloss it looks like the ETMX L2 stage was periodically saturating every 5 seconds or so
• Second lock:
  • Decided to settle at LOWNOISE_ESD_ETMX to see if this might be because of our DARM actuator changes made yesterday
  • Lost lock at LOWNOISE_ESD_ETMX. ETMX L2 stage was saturating again before the lockloss.
• Third lock:
  • Commented out the final bit of code in LOWNOISE_ESD_ETMX that transitions the L2 stage actuator from ETMY to ETMX (alog 46969 and 46973). So the DARM actuator will be ETMX L1, ETMY L2, ETMX L3.
  • Stable at LOWNOISE_ESD_ETMX for about 6 minutes.
  • Transitioned to LOWNOISE_LENGTH_CONTROL. ETMX L2 started to saturate from CSOFT pitch ringing up so I reduced the CSOFT pitch gain from 30 to 20. (maybe the increase in gain from 15 to 30 at LOWNOISE_ASC might be too aggressive?)
  • Changed DARM actuator to ETMX L1, ETMX L2, ETMX L3 by hand.
  • After, I was able to make it to nominal low noise just fine.
  • Restored actuator changes in guardian.
  • Low frequency noise (10-50 Hz) doesn't look as good as yesterday (please see second attached figure).
    • Thought this might be increased ASC noise from me reducing the CSOFT pitch gain but after looking at the CSOFT filter at NLN it looks like it's the opposite (please see third figure) so I'm leaving the CSOFT pitch gain at 20.

The following is a short summary of an approach to commissioning the H1 ITMY CO2 mask, D1900030. The purpose of the mask is to reduce the scattering of sidebands into higher order spatial modes. However, when the mask is simply applied by itself, it creates a strong positive quadratic lens. A combination of the ITMY RH, ITMX CO2 central heating and ITMX RH must be used to minimize the overall effect of the COMMON & DIFFERENTIAL MICH lenses and the COMMON and DIFFERENTIAL ITM curvatures.

First Step: Mask application to reduce HOM and maintain current quadratic lens in ITMY 

The application of the mask is illustrated in the attached PDFs. An example of the application is shown here:

• Upper left: The single-pass (SP) optical path distortion from self-heating (point absorbers) scaled to 30W of input power and assuming PRG of 40. The Gaussian weighted RMS OPD of this distortion is 25nm (where the Gaussian beam radius = 54mm). Contour spacing is 5nm.
• Upper middle: "OPD Now": The SP OPD plus 0.75W of RH power. RMS OPD = 22nm. This is what we currently have on ITMY - hence the name "OPD Now". The scatter from this OPD to LG10 is calculated (i.e. the effective lens of this OPD) as that's a number that we're going to come back to.
• Upper right: The steady-state SP OPD from the CO2 mask when a total of 450mW is applied to the ITM. The RMS distortion from this is 25nm. Note that this is the power applied to the test mass (not the power transmitted through the mask. i.e. be sure to account for the efficiency of transmission from the mask to the ITM).
• Lower left: The "OPD Now" distortion plus the CO2 mask OPD. This removes a lot of the intermediate HOM but leaves some of the very high spatial frequencies. As can be seen, there is a strong positive lens in the OPD now. 
• Lower middle: The amount of additional RH OPD required to be added to the previous plot so that the scatter into LG10 (or the effective lens of the new OPD) is the same as what we currently have in "OPD Now".
• Lower right: the sum of "OPD Now", the CO2 mask OPD and the additional RH power. This has the same effective lens as "OPD Now" but has a much lower overall RMS wavefront error of approximately 8nm.

Note that (a) the color scales have been set to the same level [-70, 70]nm for comparison between different plots [so there is some saturation in some of the plots], (b) contours are set to 5nm spacing in all plots, (c) DC levels have been subtracted from each image so that the Gaussian weighted mean value is 0nm.

Once this step has been applied, the ITMY substrate lens should be same as it currently is. This will maintain the COMMON and DIFFERENTIAL MICH lenses. However, the application of ITMY RH will change the ITMY ROC and, hence, the COMMON and DIFF ITM ROC will need to be corrected. Which will be dealt with in step 2.

The attached PDFs show the effect for differing CO2 powers ranging from 50mW to 750mW. The minimum RMS OPD is achieved around 450mW. 

TJ, TVo, Danny

• Before today, we placed the translation stage with the poker mask approximately where the annular mask was once placed. 
• Before proceeding with fine adjustments to the orientation mask we went through some initial checks as suggested in DCC T1900047.
  • Using a 3mm diameter aperture placed behind the central mask, we established how the center of the CO2Y beam on the FLIR camera correlates to the location and size of the optical path distortion on the ITMY HWS (please see first attached image). It suggests that the measured CO2 optical path distortion (OPD) we are seeing is  ~25 mm off center in the vertical direction and <10mm off center in the horizontal direction. The 3mm diameter aperture correlates to a related OPD 100 mm in diameter (it's elliptical because the beam was entering the aperture at an angle).
  • The second attached image shows the FLIR camera image with only the central mask in the beam path
• Poker mask alignment:
  • The poker mask has 4 unique geometrical shapes intended to act as a guide when attempting to understand how the HWS probe beam will measure the correlated OPD from the CO2 passing through the mask onto the compensation plage.
  • The goal was to get this poker mask centered on the HWS and get a better understanding of how the shapes are seen by the HWS so we can install the point absorber mask as intended.
  • The third attached image shows the best centering achieved today.
    • It was not obvious to TJ and myself which shapes were which from the gradient plot.
    • We may not be seeing the entirety of the shapes on the HWS which may require us to do some translating of the mask along the beam path. This is to make sure these shapes are inscribed within the projected HWS beam on the compensation plate which will be required before installing the point absorber mask.
  • While aligning the mask we developed a table describing how the movements of the mask correlated to the movement on the FLIR camera and movement of the measured OPD on the HWS:

    • Poker mask	FLIR	HWS
      Up	Down	Right
      Left	Left	Down
      Down	Up	Left
      Right	Right	Up

  • The fourth attached image shows our best estimate of how the HWS may be seeing the distortion from the poker mask-filtered CO2 on the compensation plate given the information in the table as well as the orientation of the installed mask.
  • If this HWS orientation is correct, we would want to install the mask as shown on the left in the fifth attached image.