(All time in UTC)

15:28 Kiwamu asked the intent bit to be set to comissioning. Calibration works begin.

15:30 Fil to both end stations EER (end station electronics room).

15:31 IFO lock broke. ETMX switched to high voltage

15:52 Locked at NOMINAL_LOW_NOISE. Kiwamu driving ETMX.

16:09 Fil back. Going to CER.

16:12 Fil done

16:51 EX Dust alarm went off. I checked EX dust monitor but not sure what happened to its medm screen.

17:00 Rich Abbot to LVEA. Field RF measurement.

17:13 Daniel to joined Rich.

17:40 Small re-locking issue. I didn't aware of the new method of locking PRMI so I didn't . The SRM offset was high and eventually ISI tripped. Jeff Kissel took care of the ISI.

17:51 Lockloss at SWITCH_TO_QPD see alog 20988

18:05 Locked again at NOMINAL_LOW_NOISE

18:11 Rich back for now

18:15 Rich back out

18:42 Richard to MidY

19:00 Richard back

19:07 Greg updating DMT code. This requires DMT computer restart but shouldn't affect anything in the control room.

19:15 Rich out

19:20 Nutsinee begins testing ITMX L2 DAMP MODE9 and 10 violin mode damping filters

20:00 Violin mode filtes testing stopped

20:23 Richard's intern to the roof to checck on camera

20:51 Rich back to the CER

21:00 Calibration crews took down the ifo.

23:00 Handling the ifo to Travis.

While I was out on vacation, Chris and Joe cut 3 of the 25# rolls of aluminum into 10' lengths and completed installation of those to the Mid station on the upper section of the enclosure. Additionally they have cleaned and installed strips on 240 meters of enclosure north of the Mid station to date.   

Today I replaced one of the condenser fan motors on the staging building chiller. As I was removing the motor and support/guard, the last of the spot welds broke. Had this happened during operation the fan would likely have fallen into the chiller causing a considerable amount of damage.

I took the support to the weld shop, cleaned and re-welded it.

While I had the unit disassembled, I also cleaned the coils which I would estimate were 40% blocked with debris.

 

WP 5466

Jonathan, Jim

A script has been added to gather up medm screens and put them in a tar file for exporting.  This is to support offsite viewing of medm screens for the detector.

The script runs as the controls user on script0 at 1:00 AM local time each day.  The frequency of this may be reduced to once per week when we enter O1.

Attached are ASD and Coherence betwix the three corner station STS2s taken at 3am local Wednesday Thursday and Friday.  These three days look very similar.  I installed STS2-A aka HAM2 on Tuesday.  Recap:

STS2-C (HAM5) has been in place for long time.  STS2-B (ITMY) is the unit returned from Stanford replacing PEM STS2 which we were using to replace our original STS2-B which is still at Quanterra for repairs.  STS2-A returned from Quanterra after a couple months in their vault where they say there was no problem.  The A unit spent time in the BeirGarten near the ITMy unit undergoing cable and chassis swaps, see 18354 for recap but nothing was consistent.

To me, STS2-A still looks like this unit has a problem.  When I look at plots from back in May, 18354, it looks even worse now.  There was better coherence in Z and X with the other units and Y was equally poor.

RobertS--do you have an opinion?

Travis S, Darkhan

Yesterday, Aug 27, 2015, we took Pcal end-station calibration measurements at both end-stations. The measurement procedure is described in T1500063 (-v5).

The following steps from the procedure have been completed at both end-stations:

• 3.1  DAC calibration
• 3.2  Setting up the current amplifier
• 3.3  Additional checks
• Appendix A.  Taking the measurements.

Rough numbers from MEDM screen logged into the record sheet (provided in appendix A of T1500063) suggest that RxPD and TxPD calibrations as well as optical efficiencies of Pcal beams at LHO EY did not change significantly compared to numbers from calibration on 2015-05-22, however we saw ~1 - 2 % drop in the optical efficiency of Pcal beams at LHO EX compared to measurement taken on 2015-05-20.

Calibration results will be reported after completing the last part of the calibration procedure, running Matlab scripts that acquire data and calculate responses of TxPD and RxPD:

• 4.1  Data acquisition and plots
• 4.2  Committing results into SVN

Record sheet papershots are attached to this alog.

Jenne, Nutsinee

There was a suspecious lockloss at SWITCH_TO_QPD at 17:50 UTC. We went through lockloss plots and found ASC-MICH was unstable right before the lockloss.

J. Kissel, D. Barker

Dave found that H1SUSETMY L3 LOCK L FM 2 (which has and remains OFF all throughout lock acquisition and lownoise) had been changed by Evan from compensating for the ESD driver's low pass filter (which is now done in the H1 SUS ETMY L3 ESDOUT $(QUADRANT) FM2/FM7 banks) to some other filter, and sadly did not name it so it shows up (appropriately) as "Unknown." I;m not sure what his intent was with this filter, but because is OFF all the time, I loaded the coefficients so that the model doesn't have a "modified filter coefficients" message which sets off all sorts of SysAdmin alarms.

I'll find out from Evan what his intent, and probably clean it up later.

the attached files show the current status of the front end code.

ER8 Day 11. No restarts reported

(All times UTC)

Summery:

Evan and Stefan were working on recentering the AS WFS when I arrived. When they were done, Evan cleared out his changes in the SDF aside from some ASC diff that occurred from dark offset scripts. I accepted the ODC Master changes from alog 20915.

Guardian brought the IFO into a full lock really quick, Evan added some DCPD Whitening, and it has stayed in lock since.

Locking:

• 10:28 Locked NOMINAL_LOW_NOISE
• 10:48 Intent bit set (though the HWS SLED IX was ON)

Itbit set at 10:48 UTC with long lock hopes.

New EXCITATION_OVERVIEW screen has been created:

$USERAPPS/sys/common/medm/EXCITATION_OVERVIEW.adl

Hopefully this can help in tracking down excitations that could be preventing the system from entering READY:

The two columns show the front-end excitation monitors (FEC, left) and the ODC monitors (ODC, right).

NOTE: ONLY ODC monitors count towards OBSERVATION READY at the moment.

The FEC monitors are there for reference, and for completeness.

The EXCITATIONS box in the OBSERVATION_OVERVIEW screen now contains a link to this screen.

Evan, Sheila

While the IFO was down for some calibration measurements, we made another attempt at phasing AS36. 

We first redid the dark offsets, this was an important step.  Then we locked the bright michelson with 22 Watts of input power. 

We steered the beam onto each quadrant of AS_A by maximizing the DC counts, then phased 36 to minimize Q.  There were several things that made this seem much more promising than any of our previous attempts to phase these WFS:

• The amplitudes of the signals in all quadrants were similar to within 5%
• The phases are all within 20 degrees of each other, as you would expect since the cable lengths are supposed to be matched.
• The phase that minimized Q also maximized I.
• The phasing was not very sensitive to the pointing onto the diode, as it is with DRMI locked.  
• When we turned on the centering, the phase required to minimize Q changed by 40 degrees, but the change was the same for all quadrants, and the signal levels were still similar on all 4 quadrants.  

Both of these things are firsts for these WFS as far as I'm aware, so this seemed like real progress.  

We started to do the same procedure for AS_B 36, but after we phased the first quadrant the phase jumped.  Kiwamu was in the rack working on the calibration measurements of the DC PDs at this time and reported that he had plugged a signal into the patch panel.  After this I looked at the A signals again, and they did not make sense any more. I tried repeating the procedure above for A, and found that the phases needed to minimize Q with the light maximized on each quadrant had changed by -15, -10, 0, and -20 degrees for quadrants 1,2,3,4.  

It seems like we need to make a thorough check of the HAM6 racks before we continue trying to make sense of AS WFS.  

Just for the record the momentarily sane phasings were:

Evan Stefan Daniel

The second EOM driver was installed in the CER using the 9MHz control and readback channels. The first attached plot shows the DAQ readback signals. Both drivers show the similar noise levels for the in-loop and out-of-loop sensors. They are also coherent with each other as well as ASC-AS_C! The in-loop noise is clearly below which would indicate that the signal is suppressed to the sensor noise. The measured out-of-loop noise level is also a factor of 4 higher than the setup in the shop.

The second plot shows the same traces but this time the ifr is feeding the EOM driver in the CER. As expected its out-of-loop noise level is now consistent with measurements in the shop and no longer coherent with the unit in the PSL.

We were starting to suspect that we are looking at down-converted out-of-band noise...

This entry is meant to survey the sensing noises of the OMC DCPDs before the EOM driver swap. However, other than the 45 MHz RFAM coupling, we have no reason to expect the couplings to change dramatically after the swap.

The DCPD sum and null data (and ISS intensity noise data) were collected from an undisturbed lock stretch on 2015-07-31.

Noise terms as follows:

• Shot noise
  • For 20.0 mA dc on the DCPD sum, we expect a shot noise of 8.0×10⁻⁸ mA/Hz^1/2.
• Dark noise
  • Dan and I measured this a few months ago. In full lock we use one stage of whitening, which amounts to a dark noise of 1.5×10⁻⁸ mA/Hz^1/2 or so above 100 Hz. We have at times experimented with two stages of whitening, but it requires some vigilance regarding the violin modes.
• Intensity noise
  • Coupling was measured à la Kiwamu by leaving the outer loop off and driving the inner-loop excitation point. For the noise estimation, I used the outer loop out-of-loop sensor. Since Sudarshan et al. previously found that this is artificially high, this estimation is an upper limit (though probably no more than a factor of 3, given Sudarshan's plot).
• Frequency noise [CARM sensing noise only]
  • Previously (i.e., when we locked CARM using the in-air REFL sensor), I estimated the coupling by looking at the TF in-vac REFL to DARM, and for the frequency noise estimation I used the noise of in-vac REFL as an upper limit for the frequency noise. Since we now lock with in-vac REFL, which has more light on it than in-air REFL does, I do not expect that the noise of in-air REFL is a particularly useful upper limit for the frequency noise.
  • Therefore, I have tried to instead estimate the sensing noise in CARM (from in-vac REFL, the summing-node board, the common-mode board, and PDH shot noise) in V/Hz^1/2 and propagate it (using the Izumi/Sigg expression) into a frequency noise in Hz/Hz^1/2. For the CARM optical TF I use 12.7 W/Hz at dc, with a pole at 0.48 Hz.
  • Then I have injected noise into CARM and looked at the TF from the residual of the excitation into DARM. This is the coupling TF needed to propagate the estimated sensing noise to DARM, assuming the CARM gain is high (this isn't quite true at high frequencies; the ugf is 17 kHz or so, and the gain does not exceed 20 dB until 3 kHz).
  • Since this includes sensing noise only (and not, for example, FSS noise), I have labeled it as a lower limit. In fact, the coherence between REFL 9Q and the DCPD sum is about 0.04 around 7 kHz, perhaps suggesting a frequency noise contribution of 2×10⁻⁸ mA/Hz^1/2 or so. More investigation required.
• Oscillator phase noise [not included here]
  • Stefan and I measured the coupling of the 9 MHz RF source into DARM, and using the expected performance of the OCXO estimated the noise in DARM should be 2.8×10⁻¹⁰ mA/Hz^1/2 at 1 kHz. This is quite low (and not shown on the plot).
  • This number should be replaced with Alexa's and Daniel's measurements of the phase noise. An even more satisfying number could be made by trying to measure the 9 MHz and 45 MHz phase noises in situ, closer to the EOM (e.g., at the output of the distribution system on the ISC rack).
• Oscillator amplitude noise [45 MHz only]
  • In this case we know that the 45 MHz RFAM is the dominant contributor (other than shot noise) to the DARM noise above a few hundred hertz. Here I use Stefan's estimate of the RFAM-induced photocurrent (1.8×10⁻⁸ mA/Hz^1/2), which (as he notes) is not enough to explain the excess between sum and null.
  • However, based on tonight's measurements using the new EOM driver readback, it seems that 45 MHz RFAM is enough to explain the excess. Perhaps Stefan's measurement is an underestimate, since it was done at the output of the distribution system and did not include the final rf amplifier before the EOM.
  • As for 9 MHz RFAM, Stefan and I made an estimate of the coupling from the 9 MHz source into DARM. Based on the specified performance of the OCXO, the expected noise in DARM is quite small. However, it would be better to look somewhere further downstream, as Stefan did (although I think he said the measurement was not that clean). This noise is not estimated in the plot.

The downward slope in the null at high frequencies is almost certainly some imperfect inversion of the AA filter, the uncompensated premap poles, or the downsampling filter.