I've captured dmesg and dolphin logs for later analysis, I'm now restarting all the models in the order SUS, SEI, ISC.

All models restarted with no issues. 

The CW psinject had stopped because h1calinj was restarted, and it sucessfully restarted itself now that it is under systemd control.

I cleared all the IPC errors and DAQ-CRC counters. Attached CDS Overview shows that the only red is due to the suspension models still have watchdogs enabled.

I'm handing the system over to Corey for IFO recovery.

Comparing the 0417 PCAL sweep to the latest uncertainty estimate. They match each other very well. (see details in T1900169)

I've removed the hdf5 files from the 1235600000 - 1236500000 directories in  ITMX & ITMY to bring the disk usage down to 96%. These files were backed up to LDAS so they are not lost. We should think about a long term solution to automatically remove files.

I started all four cameras back up and they appear to be taking data again.

Another way to phase the RF36 is to put the entire sum signal into the in-phase. This way the quad-phase, which is used for MICH angular control, is insensitive to centering.

After the GRB stand down was over I did this; I moved the AS_A_RF36 phases by another -28 degrees to zero the Q SUM.  This made the yaw ASC oscillations significantly smaller, although I'm not sure that they're completely gone. 

This is now 60 degrees different from the 2W value that we'd been using, and 101 degrees different from the NomLowNoise value that we'd been using.  Gah, so confusing how the ASC was even working. 

If the IFO is fussy on relock, you can still run the 'revert' command from alog 48948:

z write H1:ASC-AS_A_RF36_SEG1_PHASE_R -175 H1:ASC-AS_A_RF36_SEG2_PHASE_R -190 H1:ASC-AS_A_RF36_SEG3_PHASE_R -170 H1:ASC-AS_A_RF36_SEG4_PHASE_R -175

But, I'm hopeful that we'll be able to relock with this new phasing.  We'll see....

   The ASC Yaw signal is oscillating after the IFO has been up for the last few hours. Spoke with Jenne, and said to run the following command:

  z step H1:ASC-AS_A_RF36_SEG1_PHASE_R -1,28 H1:ASC-AS_A_RF36_SEG2_PHASE_R -1,28 H1:ASC-AS_A_RF36_SEG3_PHASE_R -1,28 H1:ASC-AS_A_RF36_SEG4_PHASE_R -1,28 -s 1 

These squeezer SDFs were fixed and reverted.  The squeezer guardian (SQZ_MANAGER) was stuck, and so we weren't injecting squeezing.  Even with the SDFs accidentally accepted, the guardian properly prevented us from going to Observing, since the SQZ_MANAGER was not in its nominal state.  It turns out that even though JeffB had toggled the squeezer's noise eater on, then off, that wasn't enough to convince the squeezer to lock all the way to injecting squeezing (we tried turning it back off only a few seconds, so that we didn't forget later). 

So, I have added to the SQZ_MANAGER guardian to turn ON the squeezer noise eater in the DOWN state, and to turn back OFF the noise eater in the SQZ_ASC state (just before it's nominal state). 

I have not yet loaded the SQZ_MANAGER guardian - this should be done next time we are out of Observing for a moment, so that operators no longer should have to deal with this.  I am leaving a sticky note with JeffB and his backup Cheryl as a reminder.

I moved the sqz noise eater ON to the Locking_TTFSS state, since it seems like we jump from Squeezing straight to Locking_TTFSS, and don't go through DOWN, so it hasn't been getting turned on.

The -20dB was put in the IMC_LOCK DOWN state (for IMC acquisition) as well as lscparams.IMC_IN1_gain.  This should be all of the places that the gain is hard-coded.  Everywhere else is relative (eg. CARM_TO_ANALOG has a +=3 to add 3dB to whatever is the current value).

I forgot to save a screenshot of the IMC OLG measurement when we had IMC-only (no IFO lock), but that had a UGF of about 41 kHz.  (I have the data, but will have to remind myself how to call the plotting scripts...)

Attached is a screenshot of the IMC OLG while the full IFO was locked at Engage_ASC_for_full_IFO, so 2W lock, CARM on its final sensor, DARM still on RF.  Looks like ~58kHz after the +3dB from CARM_to_analog.

Attached are the IMC and CM transfer functions when fully locked at 35W. The IMC ugf is around 72kHz (excellent phase margin!), whereas the CM ugf is around 20kHz.

This seems to confirm that the optical gain has changed by a factor of 10, whereas the power increase when locked is only around 7. One way to resolve this is with a small amount of light in the wrong polarization incident to the IMC. Due to the halfwave plate most of it would be directed onto the photodetectors, whereas the correct polarization would be attenuated. This would mean the shot noise limited sensitivity has gotten better by approximately 3.8, rather than 2.6 which we would have expected form a factor of 7 increase in power.   

Here is a snap shot of the updated medm screens.

Remeasured the error and control spectra of the IMC REFL servo and the LSC REFL servo signals. The IMC signals are mostly the same. The CM servo shows significant improvements at frequencies above ~30Hz. The improvement at 1kHz is a factor of ~5.7, when compare with a lock just 13 hours ago. Since we were only detecting 1.4mW of light previously, the dark noise was probably at a similar level as the shot noise.

Koji and I measured the shot and dark noise levels for the REFL and IMC PDs alog 46552.  
According to the IMC REFL plot, we were previously limited by dark noise with 1.4 mW on the PD.  Now we are squarely in the shot noise limited regime.

Continuing the Balun exchange program:

We installed new v3 Baluns on the following signals in the CER:

ISC-C4(39-1) 79.4MHz "ALS DIFF VCO Return" exchanged v1-102 with v3-S006

ISC-C4(39-2) 79.4MHz "ALS COMM VCO Return" exchanged v1-094 with v3-S068

ISC-C4(26-2) 45.5MHz "PEM Readback for Antenna Demod"  exchanged v1-055 with v3-S009

ISC-C4(19-8) 9.1MHz "PEM Readback for Antenna Demod" exchanged v1-147 with v3-S116

Work was completed per WP8190.  WP was modified to reduce impact to the IFO during this weeks maintenance, we did not touch squeezer.

Balun status can be seen here E1900100.

Continuing the Balun exchange Program:

We installed new V3 baluns on the following 45MHz signals in the LVEA:

ISC-R1 (41-6) 45MHz Auxiliary Modulation (EOM Driver) exchanged v2-DG146 with v3-S152

ISC-R2 (41-2) 45MHz Distribution exchanged v2-DG083 with v3-S094

ISC-R3 (41-3) 45MHz Distribution exchanged v1-145 with v3-S117

Work was completed per WP8200, balun status can be seen here E1900100.

I have attached Insertion Loss and Leakage scans from the old baluns as well as the new ones.

M. Pirello, D. Gustafson

Continuing the Balun exchange Program:

We installed new v3 baluns on the following signals at the PSL racks and at HAM6:

PSL-R2 (18-2) ISS AOM 80MHz exchanged DG-104 with v3-S069

ISC-R3 (41-2) Distribution 4th Harmonic exchanged v1-053 with v3-S160

ISC-R3 (41-4) Distribution 8th Harmonic exchanged v1-091 with v3-S040

ISC-R3 (39-4) Distribution 42.2MHz exchanged v1-125 with v3-S060

Work was completed per WP8215, balun status is in the same place it was last week, E1900100.

Attached is a comparision between the balun modified by hand (DG-104), and the new v3 balun which replaced it.

M. Pirello, P. King, D. Gustafson

Continuing the Balun exchange Program:

We installed new v3 baluns on the following signals at the PSL racks:

PSL-R2(17-1) FSS Modulation exchanged v1-043 with v3-S157

PSL-R2(17-2) FSS exchanged v1-014 with v3-S093

PSL-R2(17-4) PMC Modulation exchanged v1-021 with v3-S115

PSL-R2(17-5) PMC exchanged v1-050 with v3-S156

PSL-R2(17-6) Injection Locking exchanged v1-084 with v3-S095

ISC-R1(41-2) Distribution JAC Future exchanged v1-159 with v3-S092

** On the last one, the labels on the feed through may be more correct than the DCC.  I followed the cable path to the ALS VCO for the PSL.

If it is the ALS VCO, Peter told me that it is possibly 80MHz and in this case the difference between V1 and V3 is about 0.75dB more power, and no measurable difference in phase.  The PSL signals being under 45Mhz should be less than 1 degree difference in phase, and less than 0.25dB difference in power.

Work was completed per WP8208, balun status is in the same place it was last week, E1900100.

I have attached insertion loss and leakage scans of v1 vs v3 baluns.

We checked the ISC-R1 (41-2) Balun and determined this signal is the REFL_B demod, 9MHz.  There should be very little phase & power difference between V1 and V3 baluns at this frequency.

M. Pirello, D. Gustafson

Continuing the Balun exchange Program:

We installed new v3 baluns on the following signals at the end stations.

EX-ISC-C1 (41-5) Return PLL Beat Note 39.5MHz exchanged v1-176 with v3-S050

EX-ISC-C1 (41-6) Return ALS Laser VCO 79.4Mhz exchanged v1-049 with v3-S042

EX-ISC-R1 (41-1) ALS Laser VCO 71MHz exchanged v1-189 with v3-S114

EX-ISC-C1 (41-5) Return PLL Beat Note 39.5MHz exchanged v1-137 with v3-S041

EX-ISC-C1 (41-6) Return ALS Laser VCO 79.4Mhz exchanged v1-199 with v3-S155

EX-ISC-R1 (41-1) ALS Laser VCO 71MHz exchanged v1-039 with v3-S059

Work was completed per WP8222, balun status is in the same place it was last week, E1900100.

M. Pirello, D. Gustafson

Continuing the Balun exchange Program:

We installed new v3 baluns on the following signals at the Squeezer

ISC-R3 (39-1) 80MHz SQZ EOM (OPO) exchanged v1-178 with v3-S082

ISC-R3 (39-2) 35.5MHz SQZ EOM (SHG) exchanged v1-060 with  v3-S089

ISC-R3 (39-3) 200MHz SQZ EOM (CLF) exchanged v1-166 with v3-S031

SQZ-R1 (41-1) 80MHz OPO Demodulation exchanged v-122 with v3-S084

SQZ-R1 (41-2) 35.5MHz SHG Demodulation exchanged v1-020 with v3-S033

SQZ-R1 (39-3) 71MHz SQZ VCO Laser Locking exchanged v1-190 with v3-S083

Work was completed per WP8230, balun status is in the same place it was last week, E1900100.

** The 200MHz SQZ EOM CLF signal may require a slight phase change, about 8 degrees difference and 2dB more power with the V3.

M. Pirello, D. Gustafson

Continuing the Balun exchange Program:

We installed new v3 baluns on the following signals at the Squeezer and the PSL racks:

SQZ-R1 (41-3) 3.125MHz SQZ Angle Demodulation exchanged v1-171 with v3-S108

SQZ-R1 (41-4) 3.125MHz SQZ Angle Demodulation exchanged v1-145 with v3-S109

SQZ-R1 (41-5) 6.25MHz CLF Demodulation exchanged v1-183 with v3-S085

ISC-R1 (41-1) 71MHz Distribution exchanged DG-02 with v3-S086

ISC-R1 (41-3) 15th Harmonic Modulation exchanged DG-01 with v3-S058

TCS-MEZ (41-1) TCS exchanged v1-153 with v3-S079

Work was completed per WP8240, balun status is in the same place it was last week, E1900100.

M. Pirello, D. Gustafson

Continuing the Balun exchange Program:

We installed new v3 baluns on the following signals at the field racks near the PSL:

ISC-R2 (41-1) 9MHz Distribution exchanged v1-047 with v3 S019

ISC-R2 (41-3) 2nd Harmnonic Distribution exchanged v1-098 with v3-S019

ISC-R2 (41-4) 3rd Harmonic Distribution exchanged v1-157 with v3-S015

ISC-R2 (41-5) 10th Harmonic Distribution exchanged v1-179 with v3-S016

ISC-R2 (41-6) 15th Harmonic Distribution exchanged v1-074 with v3-S132

ISC-R1 (41-4) 24MHz MC Distribution exchanged v1-040 with v3-S017

ISC-R1 (41-5) 9MHz Main Modulation exchanged v1-033 with v3-S018

Work was completed per WP8244, balun status located at this link: E1900100.  This concludes all "known" balun work at the corner station.  We are sprinting to next week where we intend to replace the remaining twelve v1 baluns at the end stations.

M. Pirello, D. Gustafson

Continuing the Balun exchange Program, we installed new v3 baluns on the following signals at both end stations:

EX

ISC-R1 (41-2) 24.4MHz Modulation exchanged v1-022 with v3-S074

ISC-R1 (41-3) 24.4MHz Demodulation exchanged v1-184 with v3-S131

ISC-R1 (41-4) Not Connected exchanged v1-064 with v3-S078

ISC-R1 (39-1) 24.4 WFS A Demod exchanged v1-077 with v3-119

ISC-R1 (39-2) 24.4 WFS B Demode exchanged v1-026 with v3-S076

ISC-R1 (39-3) 71 CPS Timing Fanout exchanged v1-059 with v3-S020

EY

ISC-R1 (41-2) 24.4MHz Modulation exchanged v1-127 with v3-S073

ISC-R1 (41-3) 24.4MHz Demodulation exchanged v1-118 with v3-S011

ISC-R1 (41-4) Not Connected exchanged v1-013 with v3-S012

ISC-R1 (39-1) 24.4 WFS A Demod exchanged v1-126 with v3-S075

ISC-R1 (39-2) 24.4 WFS B Demod exchanged v1-161 with v3-S013

ISC-R1 (39-3) 71 CPS Timing Fanout exchanged v1-191 with v3-S135

Work was completed per WP8255, balun status located at this link: E1900100.  

** In the process of walking through the LVEA we found 4 more Baluns hidden among the TCS and SUS racks which need upgrading.  We were able to upgarde one of these with this Tuesday, and will finish the remainder next maintenance day.

SUS-R3 (40-1) CPS HAM 71MHz exchanged v1-011 with v3-S113

This additional work was started per WP8261

M. Pirello, H. Radkins

The final three baluns were exchanged at the corner this morning for a total of 64 baluns replaced over 14 weeks.

TCS-R2 (41-1) 71Mhz CPS Timing exchanged v1-088 with v3-S144

TCS-R2 (41-2) N/A Empty signal with Balun exchanged v1-081 with v3-S001

TCS-R1 (41-6) TCS Signal from Mechanical Room exhcnaged v1-143 with v3-S045

All work finished per WP8261.  This completes work done per FRS9794 and ECR-E1700404 at LHO.

Today I found the pressure relief line of the EndY HEPI full of fluid (a couple feet of 1/2" or something hose.)  This is usually an indication to me that the pump station experienced a high pressure event on the output.  Attached is a snap of the output pressure and the control signal around 8 March--if this is the time this over pressure occurred  it is a pretty good indication of how observant I really am given that I've been there 6 or 8 times since then!

Anyway, the plot shows that several attempts were made at restarting/repowering things after the fuse blow in the above entry.  The data shows the output of the controller at max, 2048 while things were reengaged and spiking the pressure and opening the pressure valve letting fluid escape.  The last one, I'm not sure why it was different but was at max reading, ~104 psi for 10 to 20 seconds.  This is likely the event that filled the relief line with fluid.  Looks like time for training!