The CDS web service (cdswiki) has been down since at least 11:50 PST, Evan H has kindly agreed to  restart it to see if we can clear the error.

The ITMX ISI tripped after the most recent earthquake, but the corresponding box on the ops overview screen remained green.

The trip did show up as a diag main guardian notification, however.

Edit: nevermind, it seems that the ops overview screen on video2 is frozen.

Related to: 25468, 25485

Last night, we seemed to have less number of the ETMY DAC saturation events presumably due to a combination of the new modification on the ESD driver electronics (25468, 25485) and moderate seismic and wind conditions. The DACs for driving the ESD now have more range above 152 Hz and therefore can tolerate some of the fast transients without hitting the DAC output range. As shown above, the BNS range plot from last night is cleaner than the typical O1 range plots. Looking at the undisturbed data from yesterday, we had only two saturation events (both of which occurred at the ESD stage of ETMY) out of the 9 hours lock stretch; one at the beginning and the other at roughly 10 minutes before the lockloss. See the attached trend.

The new ISS digital AC coupling caused the diffracted power to oscillate by ~1% with a period much less than 1Hz.  I tried turning the gain down on the servo, but we lost lock (we were in NomLowNoise).

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.

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.