We had another incident of ALS glitches today, this time in the X arm. We sat for a while just with the green arms locked, and the glitches became more frequent and worse and then things got better.  The glitches were bad for about an hour and a half, but you can see that something is still noisier than it was this morning. 

We have had this problem several times before: 22184

[Jenne, Kiwamu, Sheila, Nutsinee]

We were trying to lock the IFO at lower power, so that we can see how / if that changes the DARM spectrum at low frequencies, but we have (re-)discovered the fact that the ISS loop is unstable at powers other than 20W.  So, shortly after engaging the ISS second loop we lost lock twice (once at 2W and once at 10W). 

For now, we're going to skip over the engage ISS second loop state, since we need to think more before we decide to make a change. 

[Jenne, Sheila, Nutsinee, TJ]

We struggled for much of the afternoon trying to get the DRMI ASC to behave.  In the end, it seems that the SR3 OSEM values have changed now that we have a new satellite amplifier installed (see alog 25516 by Fil).  Sheila pointed out that we should trend both the WIT channels and the oplev channels for SR3, and then trust the oplev since nothing about it was changed today. 

In the attached plot, you can see that since we didn't move SR3 in yaw, the oplev value is constant but the WIT value is different.  Since the cage servo forces the WIT_P value to go to a constant pre-set value, it is the oplev that appears to move in pitch.  I have reset the SR3 cage servo setpoint to be 927, which is where it needs to be if we move SR3 so that we're back to the old oplev value.  This seems to have fixed things, and we were able to move on.

The OSEM inputs changed by about 20 counts each.

Kyle, Gerardo 

We want to know if we can use the measured exhaust flow of CP3 to distinguish between relatively low LN2 pump levels versus relatively high LN2 levels and then exploit this as part of a makeshift control loop and/or justify increasing the time interval between manual over-fills.  CP3 was last manually over-filled this past Wednesday afternoon.  So this morning, at the ~42 hour mark, we used a plastic garbage bag to capture the exhaust until the bag was taught full (see image).  We did this twice and got the following results: 

220L/90sec = 145L/min, 220L/100sec = 130L/min.  

6 hours later we manually over-filled CP3 at its normal 48 hour scheduled interval and then let the system settle down for 10 minutes or so before repeating the "bag" experiment.  This time we got the following results:  

220L/115 sec = 115 L/min.  

CONCLUSION:  

This result is surprising and not as expected.  We may instead need to have Dave B. setup the exhaust PRESSURE signal (the not-blocked sensing line) so that we can trend it (I don't think we can currently for some reason).  We already know that the exhaust pressure does vary >50% with slow over-filling so we might make a course control loop that fills CP3 based upon a preset time interval and then shuts off based upon when an exhaust pressure threshold is exceeded. 

• Title: 2/12 OWL Shift: 16:00-00:00UTC (08:00-16:00PDT), all times posted in UTC
  

• State of H1: Commissioning
  

• Shift Summary: Started out the day with Richard and Fil trying to solve a noise problem in SR3. A few other various measurements took place during that time. Then Jenne, Sheila, and I struggled with getting the ASC to engange properly during DRMI.

• Incoming Operator: Nutsinee

• Activity Log:

• 15:15 Chris S to Xarm near Xend for beam tube sealing.
• 16:19 Jim W taking HAM3 ISI down for SEI work
• 16:57 Fil to the lVEA to check SR3 sat amp
• 17:27 Hugh to LVEA to move STS to bier garten
• 17:49 Fil out and back in
• 18:06 Hugh out
• 18:28 Kyle, Gerardo to MY
• 18:35 Evan H to LVEA for some 9MHz testing
• Hugh to EY to rezero a seismometer
• 19:29 Richard to LVEA to transition to laser safe
• 19:41 LVEA Laser SAFE
• 19:56 Kiwamu done with ISS 2nd Loop work
• 20:11 Small group on roof
• 20:11 Fil out
• 20:38 Aiden Brooks changing TCS model
• 22:48 Hugh to EY again
• 23:51 Kyle, Gerardo back

Two of the three channels still seem to be stuck on the rail.  I did two centering pushes today.  I'll continue next week, hopefully it will stabilize by then.

While investigating the high frequency oscillations seen on SR3, we decided to modified the satellite amp units for OMC and SR3 (Bottom). Two decoupling capacitors were placed on the input of the negative regulator (U503), as implemented at LLO. 

C602 0.1uf
C601 10uf

The OMC units modified are S1100129 and S1100127. For the SR3 unit, we removed unit S1000287 and replaced with a modified unit S1100074. High frequency oscillations 1.7KHz and 1.9KHz seem to have cleared. Work to continue next week, as some channels still show some noise on the spectrum.

The automation of the 2nd loop engagement has been updated to use the front end funcionts (alog 25473) and confirmed to be functional.

We do not have to do the manual engagement any more. Yay.

[some more words]

I have tested the automation once as part of the full locking sequence in this Wednesday. The test in full lock exposed some minor issues with my implementation (e.g. some settings were not properly initialized and etc). Today I fixed the IMC_LOCK code so that the automation startd from the proper initial settings. I tested the new implementation with the input mode cleaner multiple times and confirmed that it was functional as intended. The automation is fully implemented.

WP--5683; ECR-- E1500455

I've center the masses now and they seem pretty good after 4 or 5 attempts.  We'll see how things have thermally stabilized after the weekend.

Also II 1203.  Otherwise:

It looks like the Block Properties specifying the parameters for HAMs4 & 5 are still just duplicates of HAM3.  See attached.  There may be more to it but at the moment I'll say, I need to correct these parameters and recompile the models to get the correct medm generated.  I'll file an integration issue as I see this as just an oversite correction.

Yesterday Jim and I resurrected the hardware watchdog (HWWD) system on the DTS. It did not take too much work as the system had been pretty much left intact. We hooked up the ADC and DAC lines to the x1susey chassis and reconfigured x1boot to PXE boot the new faster computer which is running as x1susey. This front end is running the x1iopsuseywdt  and the x1susetmywdt models. We did a quick test of setting the countdown timer to 2 minutes and then disabling the OSEM LEDS (via relay unit). After 2 minutes the HWWD zeroed the SEI enable signals. Restoring the LEDs and pressing the RESET button restored the SEI drives.

I went through the wiring and  have made a new as-built drawing as sheet 2 of https://dcc.ligo.org/D1300475

Dave, Elli

We are using two cameras on ISCT6, AS_AIR plus CAM_17, sert up at different gouy phases, which we are using to measure the SRC gouy phase.  Today we shifted the positions of these two cameras, and took some images with them as we moved PR2 and BS and tracked the spot locations across the cameras.  Attached is a photo with the changes to the table. Analysis to follow.

DIAG_MAIN - Temporarily removed the HW inj test until the CW inj are running again.

TCS_CO2 - Made the nominal state LASER_UP and added them to the GUARD_OVERVIEW medm.

(And as if on cue, H1 had a fabulous 14hr lock stretch last night with a range near 80Mpc and it was very clean/not many glitches.  See attached image.)

The local Press Conference event occuped much of the morning and went swimmingly.  After the hub bub, here are a few of the Day's Activities:

• 19:10-19:56:  Stopped the SR3 Cage Servo, & Power cycled SR3 (Keita, Kiwamu)
• 19:12:  Transitioning to Laser Hazard (Kiwamu)
• 19:35:  lveaws1 had to be rebooted (Dave)
• After the transition to Laser HAZARD, Elli & David O, went out to ISCT6 to do Guoy phase measurements with H1 in an SRY unlocked configuration.  They will be using the AS AIR camera for some of this work.

Nutsinee has kindly offered to cover the last couple hours of the DAY.

May The Gravitational Force Be With You.

Evan and I left the interferometer in the observing mode at around 20:00 pm local last night. The ISS 2nd loop now keeps correcting the diffraction power all the time via a feedack loop and maintains it at 8%.

This is yet another followup of Kiwamu's cage servo followup: https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=25416

In the attached left panel is a 12-days trend of SR3 signals. Left column is the EPICS version of M3 witness sensors, and PMON is used for the cage servo. Middle column is a DQ-version of the same signal.

At first YMON and PMON were going happy together with DQ version, but at around Feb 02/03 midnight UTC, PMON and YMON got huge at the same time the cage servo went crazy, but WIT_Y_DQ didn't feel it. Later when Kiwamu turned down the cage servo gain, WIT_P_DQ (middle bottom) went back to normal-ish but PMON and YMON didn't.

It turns out that when you look at non-DQ version of these signals (attached middle panel), there are huge lines in all four M3 OSEMs of SR3 at 1.7kHz and its harmonics, totally dominating the RMS (top). Bottom plot shows the comparison between SR3 (green) and PR3 (red), and PR3 doesn't show any of these huge lines.

DQ version is decimated by the frontend, but it seems like PMON (as well as YMON and LMON) are just sparsely sampled version of the fast signals, no filter modules therefore no decimation, thus the high frequency junk directly goes into low frequency (right panel).

In the past, the solution for oscillating satellite amps was to power-cycle them repeatedly until the oscillation stops.

Related: 20559, 19911

Summary

I remeasured the RFAM-to-DARM TFs for the 9 MHz and 45 MHz sidebands.

The 45 MHz measurement agrees with the previous result of ~0.1 mA/RAN. However, the 9 MHz measurement is also ~0.1 mA/RAN, which is a factor of 10 higher than what was measured previously. Note that the previous "9 MHz" RFAM measurement was really a simultaneous measurement of 9 MHz and 45 MHz RFAM, since we had no 45 MHz RFAM stabilization in place.

Details

For the 45 MHz measurement, I injected into the error point of the 45 MHz RFAM stabilization servo and measured the TF from the OOL RFAM stabilization detector (which is already calibrated into RAN) to the DCPD sum.

For the 9 MHz measurement, I temporarily replaced the OXCO with an IFR running at 9.1 MHz and +10 dBm. Then I used the spare DAC channel to inject into the IFR modulation port, which was set to 10 % deviation, dc-coupled (which means a RAN of 0.071 for 1 V of input, though I did not measure this directly). The signal from the spare DAC is buffered by an SR560 and sent back into one of the spare ADC channels. Then I measured the TF from the spare ADC channel to the DCPD sum. This measurement relies on the 45 MHz RFAM servo suppressing the resulting fluctuations in the 45 MHz sidebands before they are applied to the EOM; looking at the OOL readback, this seems to be satisfied below 1 kHz. Above 1 kHz, there is a RAN increase of <2 compared to no 9 MHz injection.

Templates live in my folder under Public/Templates/Osc/(45|9)_RFAM_2016-02-08.xml.