I noticed that the displayed value in the TC1 field was "#..." or absent a numeric value this morning at 0110 hrs. during a random check.  I monitored for 10 minutes and noted displayed values as 

TC1="#..." TC2=85.5 TC4=83.0 %(can't determine due to pixel resolution) 

TC1="#..." TC2=85.8 TC4=83.2 %(can't determine due to pixel resolution) 

TC1="#..." TC2=85.7 TC4=83.1 %(can't determine due to pixel resolution) 

TC1="#..." TC2=85.6 TC4=85.2 %(can't determine due to pixel resolution) 

TC1=99.9 TC2=85.5 TC4=85.5 %71 

TC1="#..." TC2=85.9 TC4=83.3 %76  

Thus, displayed value of TC1 is alternating between gibberish and valid values. 

This is a late report about the work done in HAM6 on Thursday.  Basically we have aligned things in HAM6, so that we should be able to work on locking the OPO for now. 

In the morning Nico, TJ and Terry pulled off the viewport simulator, and Gerardo and TJ removed the septum window protector so that we could attempt to inject a beam into HAM5. 

TJ and Terry recentered the osems on ZM1, which seems to have improved the performance of the damping loops (TJ is planning to remeasure the damping loops, but our experience in chamber was that it was not swinging around as badly once this was done). 

We reentered the green rejected beam on the DCPD and its reflection onto the black glass dump, which was lost when TJ and Daniel fixed the short in the diode. 

We also added the black glass clip to the last steering mirror before ZM1.  This means that we should be finished making adjustments that might change the balancing of the OPO suspension. 

Nutsinee and I borrowed the Thorlabs PZT driver from the optics lab so that we can scan the OPO PZTs more quickly which makes alignment into the OPO much easier. Nutsinee had installed a thorlabs PDA100A into the homodyne path so that we could look at the OPO transmitted power.  We found that we were not well enough aligned through the apertures on HAM6 so that the flashes we saw on SQZT6 would sometimes be clipped on one of the apperature as the OPO suspension and ZM1 were swinging.   Once we had the beam better aligned through the apertures, we can see the cavity scan for 1064 fairly well.

We decided that it wasn't worth trying to inject this beam into HAM5 and look for it returning to HAM6, since the power was so low it is hard to see the beam while scanning.

We had a hard time finding the green transmitted beam from the OPO, but with help we were able to turn off the cleanroom +LVEA lights.  This allowed us to find the beam and align onto the green TRANS PD. With the OPO suspension locked we were able to align the green into the OPO decently.  We then unlocked the OPO suspension.

Three purge air systems operating normal.

Corner pressures trended over six days.

Nutsinee Terry Daniel

Today we tried to lock the OPO in green. First, we swapped the busted 1801 with a BBPD and realigned it. The RF signal is quite large and we ended up installing a 20dB attenuator in the green EOM modulation path. As expected the green transmitted power is tiny, about 70nA when locked with ~1.3mW. We suffered from red contamination until we turned the seed off. We probably need a second dichroic beamsplitter in this path.

We first tried to lock the laser to the OPO, but soon realized that this won't work with 1MHz of VCO range. We switched to the OPO PZT and were able to keep it "locked" near resonance within about the full width. What remains looks like a ~1kHz feature that we can't suppress, since at higher gain setting we see an instability around 5kHz. The dip in reflection seems to be about ~0.7.

• five day trend of both end stations
• EX and CS

J. Oberling, E. Merilh, P. King, R. Savage

Today we confirmed our initial measurements of the FE beam propagation.  Ed and I took a couple of extra data points closer to the FE (attached as LHO_FE_Caustic_no_lens.txt, the setup can be seen in the 1st attached picture; WP02 and PBS02 had to be removed to accommodate the beam profiler) in order to more tightly constrain the divergence angle.  This was done because fits done yesterday by myself and Peter were producing different results, and indication of a possible problem with the measurement.  I used a Matlab script provided by Rick to fit this data to a Gaussian beam; Peter did the same using a gnuplot script he developed.  The 2 separate methods produced the same result: beam waist radius of 202 µm, positioned 162mm inside of the FE box.  Using JamMT to model mode matching solutions, one stood out as giving good overlap and also not giving us an intermediate focus between the lenses (which can cause problems).  This is attached in the 2nd picture as 70W_MM_Solution1-FE_caustic_no_lens.png; included is the setup for the mode matching model, with the chosen solution #9 highlighted, and the list of lenses used (all LINOS lenses we have readily on hand).  The focal lengths given are the lens focal lengths at 1064nm, taken directly from the LINOS product page.

While working all this out, we noticed something in the layout that we didn't like.  As currently laid out, any change in the beam alignment to the 70W amplifier also causes a change in alignment through the Faraday isolator (AMP_FI).  This can have an effect on the isolation provided by AMP_FI, which can in turn present a danger to the FE should a beam get back-reflected and not be properly isolated by AMP_FI (can cause crystal damage to the FE MOPA, or if we're really unlucky could amplify that back-reflection and damage down-stream components in the FE); there are also personnel safety issues to consider should a slightly off-axis beam make it back through the FE MOPA while someone is working inside the FE box.  To fix this, we removed the little zig-zag made by mirrors M33, M08, and M34.  M33 was moved 6 hole patterns further down the table (thereby giving more room for mode matching solutions as well), while mirrors M08 and M34 will serve to direct the beam onto AMP_M01 and then into the 70W amp.  AMP_FI will now reside between mirrors M33 and M08, while mirrors M34 and AMP_M01 will be the alignment mirrors for the 70W amplifier; now aligning the beam through the amplifier will not change the beam alignment through AMP_FI (before and after pictures are attached).  Ed and I placed the 70W amp in its location on the table (per the layout) and finished the change with mirrors M33, M08, and M34; there is still some alignment work to do with these mirrors.

On Monday we will install and align the mode matching lenses from the attached solution and align the beam through its new path to M34.  We will then set up the beam profiler at the waist location given to us by NeoLASE and optimize the mode matching lens alignment to get the proper beam size for the 70W amplifier.

Edit to add:  As a precaution, we installed the 80W air cooled beam dump after mirror M33.  The FE laser is ON, with watchdogs active.

State of H1:

• EY: vented, first contact applied
• MY: bake continues
• CS:
  • HAM6/SQZ:
    • in-chamber work at HAM6 is complete, or close to complete
    • ISCT6 is sitting on the North side of the chamber and is wired up
    • the SQZ table is on the South side of the chamber and is being commissioned
  • TCSX: the laser was turned on today
• MX: card access work continued today
• EX: Pcal baffle work
• all optics aligned, except ETMX and TMSX which are damped
• all SEI platforms that aren't locked are in damped or states above damped (robust_isolated)
• SEI config is in Large EQ NOBRSXY

Activity Detail:

• 09-03-18 15:12 Marm and Mark craning the lift over the beam tube in LVEA, under 500lbs
• 09-03-18 16:31 Fil to EY to work on access system
• 09-03-18 16:35 Mark to EY to get the snorkle lift and bring back to the CS
• 09-03-18 17:07 Mark to CER and LVEA to trace a cable
• 09-03-18 17:16 Mark is done moving the snorklelift
• 09-03-18 17:30 APS is at MX
• 09-03-18 17:37 Jim, Marer, Niko, Corey, to EX for Pcal baffle install
• 09-03-18 17:58 Ken to EY to remove equipment from the outside of the building
• 09-03-18 18:10 Ken back from EY
• 09-03-18 18:21 Matt to LVEA to look for iLigo TCS lasers
• 09-03-18 18:22 Travis and Betsy to EY for first contact
• 09-03-18 18:26 Terry to HAM6 SQZ table
• 09-03-18 18:29 Peter to TCS chillers to check hi and low setpoints
• 09-03-18 18:32 Fil is done ay EY and is now at MX
• 09-03-18 18:43 Chandra to MY
• 09-03-18 18:44 Karen to MY
• 09-03-18 18:44 Matt is back from the LVEA
• 09-03-18 18:50 Karen leaving MY
• 09-03-18 19:14 Fil done at MX now at MY
• 09-03-18 19:32 Mark done installing table over HEPI peer on North side of HAM6
• 09-03-18 19:32 Chandra to LVEA to spin up the Y beam manifold pump
• 09-03-18 19:46 Richard back from outbuildings
• 09-03-18 20:04 Ed and Jason out of PSL for lunch
• 09-03-18 20:16 Liz going to outbuildings for access control work
• 09-03-18 20:25 Pcal crew back from EX
• 09-03-18 20:37 Betsy and Travis to EY
• 09-03-18 20:38 Nutsinee to HAM6
• 09-03-18 20:48 Fil and Liz to MY
• 09-03-18 20:58 TVo and Olivia to LVEA to turn on a CO2 laser
• 09-03-18 21:14 TVo and Olivia back from LVEA, TCSY laser was turned on
• 09-03-18 21:18 JeffB to LVEA to reset Dust5
• 09-03-18 22:10 JeffB to EX to reset dust monitor
• 09-03-18 22:19 Nutsinee to HAM6
• 09-03-18 22:26 EY temperature has been giving alarms since 22:00 for high temperature
• 09-03-18 22:27 Bubba took a look and the temperature has leveled out at about 66F
• 09-03-18 22:27 EY setpoint is 65F so temperatures there should be coming down
• 09-03-18 22:56 Travis and Betsy back from EY
• 09-03-18 22:56 Fil and Liz at EY
• 09-03-18 23:03 Ed and Jason to PSL enclosure
• 09-03-18 23:07 Mark to Cosmic Ray detector in LVEA and CER
• 09-03-18 23:22 Mark done in LVEA
• 09-03-18 23:35 FIl and Liz back from EY and all other outbuildings

Today, Betsy and I embarked on the final First Contact cleaning of the new ETMy.  We started by taking a charge measurement with a handheld electrometer (although we didn't hold it in our hand, we used a mount specifically made for it mounted to the AERM side of the Quad lower structure).  Since the new AERM has a hole in the middle, we had questions about where to mount the electrometer.  We attempted to contact Calum from the end station, but ran into the usual working-at-the-end-station issues i.e. no GC WiFi to use WiFi calling from cell phones, no cell signal, and we were unable to locate TeamSpeak on the workstation.  Using the landline phone in these situations is often impractical since we are usually fully garbed in which case you are supposed to stay in cleanrooms and the phone is located on the other side of the beamtube.  After driving back to the corner station, we learned that the workstation does have TeamSpeak installed, but needed to be accessed via command line and there was no microphone/speaker anyways.  

We then measured the charge in 5 locations (center, upper right, upper left, lower right, lower left) and found that all 5 locations were ~10 volts.  We'll remeasure these after First Contact removal/TopGun blowoff.  We then sprayed/painted on the First Contact layer onto the HR surface of the ETM.  We'll let the paint dry and continue with chamber closeout activities on Monday.

I set the TCSX QPD dark offsets earlier today, but not TCSY QPDs offsets, and on both TCSX and TCSY QPD A and B sums I put an offset of 3 to keep the sum above zero, normal sums are around 10K counts.

In support of the CP4 bake-out, I've created a temporary Rate-Of-Change (ROC) medm and linked it as the last item on the VE pull-down on the SITEMAP. It is calculating the ROC for a CP3 thermocouple, which is actually located at CP4. When the 1-HOUR measurement exceeds 1.0degC/hour in either direction, the gray rectangle turns RED, indicating a cell phone alarm has been issued.

Note, ROC also calculates the LN2 consumption rate of EY-CP7-Dewar as a test channel (consumption is about 1% dewar capacity per day).

I have a script check_guardian_nodes_against_medm_screen which reports: nodes which exist but are not on MEDM screen, nodes which are on MEDM screen which do not exist. It produced one report: CS_BRS on the overview but does not exist. I have removed this node from the MEDM file.

Note: INJ_TRANS is white on the overview, Jamie is working on restarting this node.

WP7399

The process of offloading raw minute trend files from h1tw0 to the DAQ SATABOYS has been started. The first part of the procedure was to switch writing the current data to a new directory on h1tw1 and adding the directory which contains the last 6 months of data to the NDS archive_raw_minute_dirs list. This was done and both NDS were restarted at noon.

The next step is to use h1fw1 to copy of files from h1tw1's SSD RAID over to the SATABOY RAID (a fully compressed ZFS specifically built to hold archived raw minute). I started this process at 12:52 PST. Note that this transfer uses ionice to reduce this transfer's impact on the frame writing.

The CP4 enclosure temperature ramp is slowing down and the heater has been running at 100% for the last day. I've been increasing the temp of the GN2 flowing into CP4 so it's not a heat sink. I'm also trying to increase flow by increasing head pressure of Dewar (valve is wide open).

Kyle and I replaced a bad solenoid valve on the compressed air drying tower skid outside after getting alarms 'after hours'. Loss of compressed air caused the safety valves on the three turbo stations to close and thus spin down turbos. It also caused GV 6,8 to sag. After we regained compressed air we spun turbos back up, but YBM turbo is being difficult and keeps shutting itself down due to vibration (a known issue). We tried all the tricks with bypass valve and air admittance to load rotors. We'll let it spin 100% down tonight and try again tomorrow. I closed all three turbo isolation gate valves in a timely manner so the corner should not have been affected from back streaming. Pressure rose for a period while turbos were valved out. I didn't have time to check on in-vacuum high voltage equipment - don't think anything was turned on.

FYI: we did not replace the solenoid portion of the valve at the drying tower.

After ~3 days of ground loop hunting, fixing, breaking, fixing as well as a relocking of the ISI, we finally are getting good results on the 18 DOF transfer functions for all 3 suspended chains in BSC10 (ETMY main, ETMY reaction, and TMS).

Attached are results of the TMS.  Peaks from today overlap peaks from previous closeout sessions.

Kissel has cast an eye on these and calls them good.

Will post the ETM set shortly.

Next up:  First contact and electrometer optic readings, chamber clean-out, then closeup!

After a lot of experimentation, I have found a way to improve the attenuation of frequencies below 9 Hz in the calibration by 1-2 orders of magnitude, without significantly increasing the computational cost or latency of the pipeline. Here is a list of what I've changed and what I've kept the same:

• In the actuation path, before the actuation filter, I have added a separate high-pass filter using Matlab's firls() function (documentation). firls() designs a linear-phase FIR filter that minimizes the weighted integrated squared error between the desired frequency response in specified intervals and the approximated response of the filter. The filter I've found most effective is designed to have a frequency response of 1 from 9 Hz to the Nyquist rate, and 0 from DC to 8 Hz.  I found improvement when I weighted the stop band more heavily by a factor of 100.  This filter was 2 seconds in length for the tests that I ran.
• I shortened the actuation filter itself from 6 seconds to 4 seconds. (The main reason we needed such a long filter before was to prevent spectral leakage, which is now taken care of by the previous high-pass filter.) It still contains half of a Hann window to the fourth power to roll off low frequencies, in order to further attenuate those frequencies. I found that this roll-off actually worked better than any version of least squares filter I tried in its place.
• In the inverse sensing filter, I replaced the half Hann window to the fourth power with Matlab's least squares filter using firls(). For some reason, this worked better in the inverse sensing filter than the Hann window stuff, even though it did not work better for the actuation. I designed this filter to have a frequency response of 0 from DC to 5 Hz (weighted by a factor of 100) and a frequency response of 1 from 9 Hz to the Nyquist rate. This is what seemed to produce the best results. I did not add a separate high-pass filter in the inverse sensing path, as it seemed unnecessary, and filtering at 16384 Hz gets expensive.

Of all the things I tried, this is what worked the best. Reasons I did not make this even better include:

• I haven't figured out a better way yet
• It is possible to do better with longer or more filters, but since we are doing this in the time domain with FIR filters, adding more filtering gets computationally expensive and adds latency. It is necessary to balance computational cost with quality, as we do not want the pipeline falling behind in low-latency or taking forever to produce offline data on the clusters.

Several plots are attached to show the new features. The first 5 plots are the frequency responses and comparisons to the ideal models for each of the filters used. The last 3 plots are comparisons of C01 data with data produced using the new filters. The attenuation is better by about 1-2 orders of magnitude, and there is just a very small amount of ripple added below 20 Hz.