IMC was relocking but not holding.  Talked to Sheila, and she showed us how to toggle the Noise Eater - picture attached showing the switch.

IMC relocked, PSL ISS came back bad, with the loop being toggled on/off due to power, so Jason adjusted the REFSIGNAL to bring the Reflected power back to about 10% where ISS is stable.

- Sheila, Jason, Patrick, Cheryl

On the ISC_GUARDIANS.xml, ISC_LOCK pull down menu has two states named "Down" - why?

Picture attached.

J. Oberling, P. King, E. Merilh

Summary

We realigned the beam into the PMC and adjusted the position of the mode matching lenses to improved the power transmitted by the PMC.  At the then end we had PMC TRANS = 23.3 W, PMC REFL = 1.9 W, and a visibility of 91.1%.

We then tested the TTFSS box that Peter had modified.  We were able to get the FSS to lock with the modded box, but when we looked at the TF we noticed some ugliness between 200 kHz and 300 kHz.  Peter has pictures of the TF and the data so he can post those.  The UGF of the modified box was around 220 kHz, this with the common gain maxed at 30 dB.  It was decided that to continue to work on the modded box, so we reinstalled the original TTFSS box and restored the common and fast gains to where they were before we swapped boxes.

Details

The PMC before we started working:

• TRANS: 22.2 W
• REFL: 2.5 W

The FSS and ISS were turned off, PMC TRANS changed to 23.0 W.  We first adjusted the beam alignment into the PMC using mirrors M06 and M07.

• Adjust yaw first, walk the beam south
  • TRANS: 23.5 W
  • REFL: 2.0 W
• Adjust pitch, walked the beam up
  • TRANS: 23.5 W
  • REFL: 1.9 W

As can be seen the majority of the gain was in yaw.  At this point we measured the RPD voltage in both the locked and unlocked state and calculated the visibility

• PMC unlocked: -1.51 V
• PMC locked: -0.142 V
• Visibility: 90.6%

Then the mode matching lenses L02 and L03 were tweaked in position to see if we could gain anything.  Once this was done we had to tweak the alignment again using mirrors M06 and M07 and calculated the visibility.

• Lens positions before move
  • L02: 13.68 mm
  • L03: 6.29 mm
• Lens positions after move
  • L02: 13.38 mm
  • L03: 6.42 mm
• PMC power after realignment
  • TRANS: 23.5 W
  • REFL: 1.9 W
• RPD voltage
  • PMC unlocked: -1.51 V
  • PMC locked: -0.134 V
  • Visibility: 91.1%

We then tested the modified TTFFSS box.  With the modified box the FSS was able to successfully lock.  We then measured the TF of the FSS servo and noticed that between 200 kHz and 300 kHz the TF was fairly noisy.  The UGF was at ~220 kHz with the FSS common gain slider maxed at 30 dB, but the noise caused the TF to cross unity a couple different times, with a final crossing around 280 kHz.  Peter has the full TF data with pictures that he will post.  We decided to pull the modified box out and reinstall the original.  The common and fast gains were returned to their original values (20.5 dB and 22.2 dB respectively).

Finally we relocked the FSS and ISS.  Upon ISS relock, the diffracted power went up to ~45%; the refsignal had to be changed to -2.56 to bring the diffracted power down to ~6%.  While this is unusually high, the ISS seemed happy so we left it as is and will monitor it.  The final PMC powers after FSS and ISS relock are:

• PMC TRANS: 23.3 W
• PMC REFL: 1.9 W

This time at 10 W.

The h1ldasgw0, h1ldasgw1, h1fw0, h1fw1, h1nds0, h1nds1, h1dc0 and h1broadcast0 computers were powered off and restarted this afternoon.  Updates were applied to the h1ldasgw0 and h1ldasgw1 computers to bring them to the same OS version.  An fsck was performed on h1fw0, which had gone 343 days without a check.  An fsck was also performed on h1nds0 which had gone 272 days without a check.

It is hoped that this maintenance will solve the instability which has caused the frame writers to restart many times per day over the last few days.

We continue the charge measurements on ETMs.
Some point's of today's data could be saturated due to the other activities at the end stations.
Plots are in attachment. Voltage is more or less the same, and it's early enough to consider the tendencies since changing the bias sign (See alog 19848, 19821).

Last night I measured the change in spherical power in ETMX during a 50 minute, 25.5W lock stretch (Started ~23 Jul, 00:05:00 UTC) using the same method last night's measurement,  see alog 19835.  The change in spherical power was 20 microdiopters, which means 21.2mW of power was absorbed.  According to the ASC_TR_X_A/B PDs the power in the arm was 132kW (+/- 15%), which puts the absorption in the ETMX at 160(24)ppb.  The absorption of this optic is 330ppb, according to the galaxy website, so our measurment does not agree with this previous value.

Attached is a plot of ETMX and ETMY spherical power change during this lock stretch.  There are some big glitches in the HWS spherical power, which correspond to where I briefly closed the green beam shutters. The ETMY spherical power looks dodgy.  I will adjust the misalignment of the green beam onto the ETMY and see if we can get a decent measurement.

Things that probably happened, but of no impact to the IFO:

- WP5377 - Bubba, fan, LSB

Things that happened:

- EY to check SUS ESD cables, Andres, started 8:34AM, done 10AM, no cables changed

- WP5379 - JeffK, SUS and SEI IPC - done 9:00AM

- HEPI EY transition, Jim, started 9AM, done 10:49AM

- HEPI, Hugh, to EY, started 10AM, done 10:49AM

- ETMX charge measurement, Leo, started 9:50AM, done 10:54

- HEPI blend filters, Jim, EX, done 10:55

- WP5381 - Richard, Vault Seismometer, started 9AM, done 10:43AM

- High Bay door opened, Andres, 11:10AM

- WP5378 - Daniel, Beckoff, started 9AM, done 11:25

- PEM, mid-Y and EY, Vinney, started 10:46AM - done 11:34AM

- WP5350, Jason, PSL PMC, PMC and FSS electronics, Done 12:30

- TCS, Nutsinee, TCSX HWS align, started 10:50AM, Done 12:30

- WP5376 - Jonathan, CDS EPICS Gateway, started 8:24AM - assumed done

- ETMY charge measurement, Leo, started 10:50AM - assumed done

- ETMX PCAL, Sudarchan, started 9:58, Done 12:57PM

- WP5380  - JeffK, CAL-CS, started 12:54PM, done 12:57PM

- DAQ NDS0 full reboot, Dave - currently in process

Things that are waiting for a window of opportunity:

- WP5349, Filiberto, LVEA Cosmic Ray Detector, started 8:37AM, still work to do if there's a window, ~1 hour

- Low ESD at ETMX, Filiberto, still work to do if there's a window, ~30 minutes

Because of the clipping on both edges (left and right) on the first mirror, this is as pretty as it's gonna get. An in-air solution that could possibly be done is to replace the first few mirrors with larger ones. The Hartmann plate is put back on.

Richard M. Vinny Roma,

This morning we pulled our wagon of toys out to the vault to installed the STS-2 seismometer and return the Magnetometer coils to the vault.  After getting lost in the desert we were able to locate the Vault.  The seismometer was installed and cabled.  We know there are signal problems but that can be addressed later.  Getting all the material out to the vault before it got too hot was the goal for today.  After Gerardo powered up the battery charge we had power to the fiboxes and Vault so signals to the mid station.  I was able to confirm the cabling for y and z channels but not x as it is railed at the mid station.  I will continue to work on this system to get all of the signals working.  Probably will need another excursion to the vault to push the centering servo button.

Thank to Vinny for all his help.  I would still be out in the desert had he not helped.

On Tuesday the fluid level in the EndY HEPI Reservoir was found to be 1/2" lower in just one week.  As I suspected, a leaking schrader valve was the problem.  All seven accumulators on the EndY system are at the same pressure as last week except the one on PRESS2 at the pump station.  It was exactly zero.  After charging, the saliva test showed a very suttle leak and tightening the schrader valve was repeatedly not successful.  The valve was replaced and it seems to be holding now.

This accumulator is charged to 78 psi and losing this one unit is responsible for the entire 1/2" fluid drop.  I can imagine the relation between accumulator pressure and fluid level in the reservoir is maybe not linear.  But maybe close, so at the ends, to maintain the spec of 60-93% accumulator charge, a fluid drop of only ~3/16" could be too much.  But this would be the case if it is only one accumulator.  Many could be at 80% say and we might hit the 1/4" fluid drop threshold.

Let's make this easy: if there is no observed fluid drop, the accumulators are likely fine.  If the level drop is more than 1/8", that is likely outside the typical temperature fluctuations and the system should be checked for actual fluid leaks and accumulator charge loss.

Given that this accumulator is before the second laminar flow resistor and the 3rd accumulator on the pump station, and, remember there are two more accumulators at the chamber before the HEPI Actuators, I suspect this one accumulator loss will have had little affect on PS pressure fluctuations coupling into platform motion.  But, that will be determined by data rather than supposition--so data to come.

The serial port of the Trimble Thunderbolt E GPS has been connected to the second port of the serial concentrator. (The third port doesn't seem to work.) The default baud rate is 9600 8N1 which is what we are using in the EtherCAT terminal as well.

Attached are the new auto-generated screens. An error will be generated, if the GPS is not synchronized.

GPS user's guide: E1500318

To fix the problem of accidental PUM/ESD crossovers near the violin mode resonances, the PUM is now rolled off more aggressively above the crossover (see attachment of EY L2 LOCK FM6 vs FM7, where grey is old and purple new).

Previously, the PUM had an f² plant inversion out to about 600 Hz. It is now more like 300 Hz. There is also a broad notch around the first violin mode just to make sure that we do not have an accidental crossover there.

DARM OLTF attached (blue and red are essentially part of the same measurement). The high end of the phase bubble has flattened out a bit.

The PUM/ESD crossover was remeasured and was found to be satisfactory (attachment). Additionally, the rms drives to the three stages seem to be acceptable as well (attachment), although these were taken during low seismic activity.

The guardian request and state was DOWN when I arrived.

I had some trouble with tuning the VCO to manually find the IR resonance in the CHECK_IR state. The wiki instructions said to use the LSC overview screen but should have said the ALS overview screen. Ed has updated them. I think I was also using the wrong slider. I was using the 'Tune Ofs (V)' slider and it was fighting me. I think I was supposed to use the 'Set Off (Hz)' slider. I will confirm this with commissioners and add this to the wiki.

It eventually reached DRMI_LOCKED twice. In both instances it lost lock on its way to ENGAGE_ASC. The first time was from PREP_TR_CARM. The second time was from CARM_ON_TR.

Dave, Daniel

(I meant to post this a couple of weeks ago but hadn't gotten around to it.) I compared ~2 hours of the 1PPS signal from the old GPS clock installed in EY to the aLIGO Timing Distribution System's 1PPS signal and found, as expected, a near-constant time difference of order 100 ns (likely attributable to antenna and 1PPS cable length). The jitter, which is the more important feature, was nicely contained to 3 clock cycles, with a standard deviation of no more than two clock cycles (the narrow bands in the histogram are due to the comparator's measuring time difference based on clock cycles).

The 1PPS signal was present from precisely 6-23 19:52:34 UTC (12:52:34 local) to 6-23 21:52:29 UTC (2:52:29 local), a total of just under 2 hours. I'll follow this up with a long-term timeseries and histogram showing the time differences between aLIGO Timing Distribution and the new GPS clocks installed at both end stations.

We observed broadband coherence of OMC_DC_SUM with ASC_AS_C_LF_SUM and ASC_A_RF36_PIT. We made some numbers and plots, using the 64kHz version of the channels.

First the measurements we made on OCXO oscillator:
- ASC_AS_C sees a RIN of about 5e-7/rtHz above 100Hz (either from H1:ASC-AS_C_SUM_OUT_DQ or from H1:IOP-ASC0_MADC6_TP_CH11). The same is true for its segment 1.
- The calculated shot noise RIN at 20mA (quantum efficiency 0.87) detected is 4.0e-9/rtHz.
- The 4.0e-9/rtHz agrees with DCPD_NULL_OUT_DQ's prediction (8.0e-8 mA/rtHz/20mA).
- DCPD_SUM_OUT_DQ sees a slightly elevated RIN of 4.6e-9/rtHz (9.2e-8 mA/rtHz/20mA).

- The RIN in DCPDA (H1:IOP-LSC0_MADC0_TP_CH12, corrected for the whitening) is about 5.9e-8 mA/rtHz, or RIN = 5.9e-9/rtHz at 20mA/2diodes (~15pm DARM offset)...
- ...or about 3.3e-8 mA/rtHz or 1.2e-8/rtHz at 5.7mA/2diodes (~8pm DARM offset).

- ASC-AS_C_SEG1 (H1:IOP-ASC0_MADC6_TP_CH11) and OMC-DCPD_A (H1:IOP-LSC0_MADC0_TP_CH12) shows a coherence of 0.053 at 20mA, suggesting a white noise floor a factor of 0.23 below shot noise.
- At 5.7mA the same coherence is about 0.13, i.e. the white noise floor is a factor of 0.39 below shot noise.
- These two measurements are in plot 1.

- Taking the last two statements together, we predict a coherent noise of
  - 5.9e-8 mA/rtHz *0.23 = 1.4e-8 mA/rtHz at 20mA/2diodes (~15pm DARM offset)  (RIN of coherent noise = 1.4e-9/rtHz) - The pure shot noise part is thus 5.7e-8 mA/rtHz
  - 3.3e-8 mA/rtHz *0.39 = 1.3e-8 mA/rtHz at 5.7mA/2diodes (~8pm DARM offset)  (RIN of coherent noise = 4.5e-9/rtHz) - The pure shot noise part is thus 3.0e-8 mA/rtHz.

- AS_C calibration:
 - 200V/W (see alog 15431)
 - quantum efficiency 0.8 (see alog 15431)
 - 0.25% of the HAM 6 light (see alog 15431)
 - We have 39200cts in the AS_C_SUM. Thus we have
   - 39200cts / (1638.4cts/V) * 10^(-36/40) (whitening) / (200V/W) = 1.89mW and AS_C. (shot noi
   - 1.89mW/0.025 = 76mW entering HAM6. I.e. we have slightly more sideband power than carrier power (Carrier: 27mW in OMC transmission).
   - Shot noise level on AS_C_SUM is at 2.0e-8 mA/rtHz, corresponding to a RIN of 1.6e-8/rtHz. I.e. the coherent noise seen at 5e-7/rtHz is high above the shot noise. Dark noise TBD.
   - The light entering HAM 6 has a white noise of 5e-7/rtHz*76mW = 3.8e-5 mW/rtHz 
    

Bottom line:
 -We have ~1.4e-8mA/rtHz, or 1.9e-8mW/rtHz of coherent white noise on each DCPD.
 -It corresponds to 3.8e-5mW/rtHz before the OMC, i.e. the the OMC seems to attenuate this component by 2000.
 -This noise stays at the same level (in mW/rtHz) for different DCPD offsets.


Next, we switched back to the IFR for testing. plot 2 shows the same coherences (all at 5.7mA / 8pm DARM offset), but on the IFR. Interestingly now AS_C and AS_A_RF36 start seeing different noise below 2kHz. We convinced our selfs that the higher excess noise seen in AS_A_RF36 is indeed oscillator phase noise from the IFR - so that is clearly out of the picture once of the OCXO. (Evan will shortly log the oscillator phase noise predictions.)


64k Channel list:
H1:IOP-LSC0_MADC0_TP_CH12:     OMC-DCPD_A  (used in plot)
H1:IOP-LSC0_MADC0_TP_CH13:     OMC-DCPD_B
H1:IOP-LSC0_MADC1_TP_CH20:     REFLAIR_A_RF9_Q
H1:IOP-LSC0_MADC1_TP_CH21:     REFLAIR_A_RF9_I
H1:IOP-LSC0_MADC1_TP_CH22:     REFLAIR_A_RF45_Q
H1:IOP-LSC0_MADC1_TP_CH23:     REFLAIR_A_RF45_I
H1:IOP-LSC0_MADC1_TP_CH28:     REFL_A_RF9_Q
H1:IOP-LSC0_MADC1_TP_CH29:     REFL_A_RF9_I
H1:IOP-LSC0_MADC1_TP_CH30:     REFL_A_RF45_Q
H1:IOP-LSC0_MADC1_TP_CH31:     REFL_A_RF45_I


H1:IOP-ASC0_MADC4_TP_CH8:      ASC-AS_A_RF36_I1
H1:IOP-ASC0_MADC4_TP_CH9:      ASC-AS_A_RF36_Q1
H1:IOP-ASC0_MADC4_TP_CH10:     ASC-AS_A_RF36_I2
H1:IOP-ASC0_MADC4_TP_CH11:     ASC-AS_A_RF36_Q2
H1:IOP-ASC0_MADC4_TP_CH12:     ASC-AS_A_RF36_I3
H1:IOP-ASC0_MADC4_TP_CH13:     ASC-AS_A_RF36_Q3   (used in plot)
H1:IOP-ASC0_MADC4_TP_CH14:     ASC-AS_A_RF36_I4
H1:IOP-ASC0_MADC4_TP_CH15:     ASC-AS_A_RF36_Q4

H1:IOP-ASC0_MADC6_TP_CH11:     ASC-AS_C_SEG1  (used in plot)
H1:IOP-ASC0_MADC6_TP_CH10:     ASC-AS_C_SEG2
H1:IOP-ASC0_MADC6_TP_CH9:      ASC-AS_C_SEG3
H1:IOP-ASC0_MADC6_TP_CH8:      ASC-AS_C_SEG4

I was running an ASC OLTF swept-sine template with a request for a 10 s rampdown time.

From the EXCMON of the drive channel, it seems that this rampdown did not happen. Rather, the excitatation continued at full strength for about 10 s and then cut off abruptly.

Tonight we have a nice example of one of the particularly troubling lockloss types that we have.  

Jenne, Sheila, Evan

We locked at 10Watts with low noise, and redid the OMC excitations that Koji and I did in alog 17919.  We plotted the OMC L excitation against a model with a peak to peak motion of 36 um, and the result seems consistent with a reflectivity of 160e-7 that we measured on Friday by exciting the ISI.  This is slightly worse than what we measured in April.  

We made these excitations with the same amplitudes and frequencies that we used in April, but some of the velocities seem to be smaller.  Jenne is working on doing a more thourough comparision, but it seems that the scatter is better when we are exciting Yaw and Transverse, if a little worse for longitudnal.  

We used a frequency of 0.2 Hz for all excitations.