(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.

Stefan, Evan

We made another attempt at using 90 MHz to center WFS AS B.

This time we turned up the whitening gain to 45 dB, which gave a healthy number of counts on each quadrant. We then redid our dark offsets, which were significant at this whitening gain. [We actually redid the dark offsets for all the REFL and AS WFS signals using the script in the userapps repo.]

Then in DRMI, we phased each quadrant to put most of the power in I. At this point we saw that the centering signals provided by these 90 MHz quadrants (pitch and yaw) were slightly different than the dc centering signals for AS B, so we switched the centering over to these signals (a relative gain of −0.003 is required between these 90 MHz signals and the dc signals). Things seemed fine in DRMI (the sideband buildups all changed slightly, but it was hard to say whether they were better or worse), but when we tried the CARM reduction sequence, the new centering ran away on the DARM WFS step.

So instead, we went to full lock at 2 W with the old centering scheme and switched over again to the new 90 MHz AS B centering. Things again seemed fine.

We weren't quite sure what to do about the BS/SRM matrix elements. In the end we tried using AS B 36 I&Q only to control these loops (i.e., no mixture with AS A 36), and this was fine at 2 W, but we lost lock immediately when trying to power up.

C. Cahillane, D, Tuyenbayev

In a previous alog alog 20946 I showed preliminary carpet plots of ER7 strain uncertainty based on changes in the calibration parameters |kappa_tst|, φ_kappa_tst, |kappa_pu|, φ_kappa_pu, kappa_C, f_c.
Here are some updated plots.  (Plots 1 - 6)

The data is now low-noise, and is dewhitened.  This gives much nicer, more accurate results.
I have been working to reproduce Darkhan's carpet plots from T1500422.  The method he uses to find error in Delta_L_ext is as follows:

delta Delta_L_ext =  C_true / (1 + G_true)     
                             ------------------------------
                                        C / (1+G)

where C_true and G_true are the quantities where kappa_tst, kappa_C, and f_c are varied.

The method I use to find error in strain is:

delta strain = (1 / C_true) * d_err + A_true * d_ctrl
                      ----------------------------------------------
                                  (1 / C) * d_err + A * d_ctrl

Plot 7 is Darkhan's method of computing error from changes in kappa_tst reproduced by me.
Plot 1 is my method of computing error from changes in |kappa_tst|.  They should be the same.  They aren't.

We are searching for potential reasons behind the structure found in Darkhan's plot.  Something odd may be going on at the UGF of the CLG, causing the low magnitude error near 65 Hz and low phase error near 35 Hz.
My plot, on the other hand, has no low error region in phase, in fact it has a maximum near 35 Hz, and has a tilted low magnitude error region between 30 and 40 Hz.

I am investigating this difference now.

23:00 (16:00) Darkhan and Travis at end Y running PCAL measurements. Leo running charging measurements for ETMX.
23:36 (16:36) Kiwamu to electronics room to measure transfer function of whitening filter
23:40 (16:40) Evan to CER to run measurement with network analyzer
23:41 (16:41) Darkhan and Travis done at end Y, moving to end X
00:09 (17:09) Nutsinee to TCS X to take picture of control box
00:15 (17:15) Nutsinee back
00:44 (17:44) Evan done, Leo done
01:18 (18:18) Travis and Darkhan done at end X
01:37 (18:37) Travis and Darkhan back

02:13 (19:13) Kiwamu and I start locking
Trouble locking on DRMI
Ran through initial alignment starting with CHECK_IR
Lost lock engaging ASC WFS in LOCK_DRMI, Kiwamu had to revert phase settings for AS 36
Lock loss on bounce mode
03:17 (20:17) h1fw2 crashed and restarted
04:48 (21:48) Locked on Low Noise, Darkhan running calibration measurements

05:22 (22:22) Darkhan done, Stefan and Evan starting wiggling cables test
05:26 (22:26) Kiwamu to CER to clean up previous work
Kiwamu is back
06:22 (23:22) h1fw2 crashed and restarted
07:00 (00:00) handing off to TJ, Evan and Stefan are investigating RF

Other
end Y dust alarms
smelled a lot of smoke in hallway, went up to roof, didn't spot any fires

J. Kissel, K. Kawabe

Similar to what is shown and briefly mentioned in LLO aLOG 18406, I've done a comprehensive transfer function study between the DAC and ADC Duotone timing signals from the following IO chassis:
h1lsc0 (which houses the ADC for the OMC DCPDs),
h1susex & h1susey (which house the DACs for the ETM QUADs)
h1iscex & h1iscey (which house the ADC for the PCAL RXPDs)
h1oaf0 (which receives the DARM_ERR and DARM_CTRL channels from the OMC model over IPC)
Recall that these Duotone signals are merely *checks* on the system that is actually providing the time signals for the DAC / ADC cards, which is the 1 PPS signal from the local timing fanout in the building (which in in turn receives its 1 PPS from the timing master in the corner station which is GPS synchronized). The results indicate that -- although there is a few tens of micro-second offset between all of these front-ends, they appear to not *differ* by more than a few hundred nano-seconds, and typical in the tens of nano seconds. This is consistent with what Shivaraj found when making the comparison between his l1iscex and l1iscex against l1oaf0. Recall that our requirement is that the timing uncertainty is no greater than 25 [us], so at least the DuoTone signals between each IO chassis fall in well-below this. What we would need to do to confirm that the actual front end timing is to then compare this DuoTone against the "digital world" 1 PPS, as Keita has done for the ADC and DAC DuoTone signals for all of the above mentioned chassis in LHO aLOG 20962. His aLOG also indicates a ~100 [ns] difference between chassis, on top of the ~7 [us] offset.

So far, so good in timing land.

Details:
---------
For all measurements, I used h1lsc0 ADC and DAC duotone singals as the reference (TF denominator), and the others as the response (TF numerator). Below are the results for the phase relationship between each at 960 [Hz] (the results are the same within the precision stated for the 961 [Hz] line):
          xxxx ADC      xxxx DAC      xxxx ADC     xxxx DAC
          --------      --------      --------     --------
          LSC0 ADC      LSC0 ADC      LSC0 DAC     LSC0 DAC

h1lsc0       n/a         -26.42        +26.42         n/a
h1susex    +5.14         -21.27        +26.45       +5.14
h1susey    +5.13         -21.28        +26.44       +5.13
h1iscex   +0.008         -21.29        +26.45       +5.13
h1iscey   +0.028         -21.27        +26.47       +5.14
h1oaf0    -0.013         -21.34        +26.43       +5.07

which we can turn in to an equivalent delay (or advance) between the two front end timing signals, with 1e6 * (pi/180) * phase_deg * / (2*pi*961 [Hz])
          xxxx ADC      xxxx DAC      xxxx ADC     xxxx DAC
          --------      --------      --------     --------
          LSC0 ADC      LSC0 ADC      LSC0 DAC     LSC0 DAC
            [us]          [us]         [us]          [us]
h1lsc0       n/a         -76.4         76.4          n/a
h1susex     14.9         -61.5         76.5          14.9
h1susey     14.8         -61.6         76.5          14.8
h1iscex     0.023        -61.6         76.5          14.8
h1iscey     0.081        -61.5         76.6          14.9
h1oaf0     -0.038        -61.7         76.5          14.7

Templates live in 
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/ER8/H1/Measurements/Timing/
2015-08-27_H1LSC0_to_CALCS_DuoTone_TFs.xml
2015-08-27_H1LSC0_to_ISCEND_DuoTone_TFs.xml
2015-08-27_H1LSC0_to_SUSEND_DuoTone_TFs.xml
of which I attach an example.

Sudarshan, Darkhan

Overview

Today we took PCALX to DARM and PCALY to DARM TF measurements.

These measurements will be used to assess time delays/advances between Pcal excitation/readout channels vs. DARM_IN1.

Details

Earlier today we took PCAL(X|Y) to DARM TF measurements for estimating timing of Pcal channels vs. DARM_IN1. We noticed that in today's earlier measurements "2015-08-27_PCALX2DARMTF_TIMING.xml" and "2015-08-27_PCALY2DARMTF_TIMING.xml" used log.spaced frequency vectors. Since later in the day we got another opportunity to measure these transfer functions, we repeated earlier measurements but this time taking a linearly spaced frequency vector.

So the most recent measurements taken at a lin.spaced frequency vectors are (notice that they also include earlier log.spaced measurement TFs and coherences as ref0 and ref1):

• 2015-08-27_PCALX2DARMTF_linspace.xml
• 2015-08-27_PCALY2DARMTF_linspace.xml

All 4 measurements have been uploaded to calibration SVN (r1161):

CalSVN/aligocalibration/trunk/Runs/ER8/H1/Measurements/PCAL/2015-08-27_PCALX2DARMTF_linspace.xml
CalSVN/aligocalibration/trunk/Runs/ER8/H1/Measurements/PCAL/2015-08-27_PCALX2DARMTF_TIMING.xml
CalSVN/aligocalibration/trunk/Runs/ER8/H1/Measurements/PCAL/2015-08-27_PCALY2DARMTF_linspace.xml
CalSVN/aligocalibration/trunk/Runs/ER8/H1/Measurements/PCAL/2015-08-27_PCALY2DARMTF_TIMING.xml

Charge measurements was done on both ETMs.
It seems like ETMY change the sign of charging after changing the bias sign on ETMY (see 20387) while ETMX charging is the same (as well as the bias sign).
Now (since Aug,10) both ETMX and ETMY Biases are -9.5V, 
Plots are in attachment.

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.

(All time in UTC)

15:15 Christina opening the roll-up door, OSB receiving area

15:30 Christina done

16:36 Kiwamu to electronics area by PSL and HAM6

16:59 Sudarshan has been doing Pcal swept sine. Now done.

           Kiwamu done

17:00 Observing intent bit set. SDF hasn't been cleared at this point. See attachment.

17:34 Bubba to Mid station

18:03 Intent bit switched to Commissioning. Flipped DHARD 20-30 Hz BP filters.

18:05 Intent but switched back on

18:33 Kyle to beam tube near EY to make measurement. 300 m away from EY.

18:36 Wind picking up. Reaching 30 mph.

           Intent bit swited to Commissioning. Daneil to CER.

18:53 Daniel back. Intent bit Observing.

19:00 Calibration group taking over. Bring interferometer to down. Intent bit set to Commissioning

19:11 Kiwamu to LVEA doing OMCDCPD measurement

19:23 Fire protection Specialists back on site. Fire suppression in Network Room.

19:30 Sheila to LVEA looking for Kiwamu.

19:38 Kyle back

20:47 Sheila locking MICH

           Something water on site. Couldn't hear the guy. Let a white pick-up truck in.

21:09 Bubba done

21:42 Travis, Sudarshan, Darkhan to EY (Pcal calibration)

19:02 Hand the ifo over to Patrick

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:

J. Kissel, K. Kawabe, S. Karki

We've broken observation mode such that we can enable the DAC DuoTone timing readbacks on the front ends that are responsible for DARM control, i.e. h1lsc0, h1susex, and h1susey. We needed to take the IFO down for this because the last channel on the first DAC cards for the end station SUS are used for top-mass OSEMs for damping the suspensions. If the damping loops get a two sign waves at 960 and 961 [Hz] instead of the requested control signal for one of the OSEMs, then we get bad news.

Here are the times when the DAC DuoTone switches were ON for the following front ends:

h1susex and h1susey --- 19:04 to 20:04 UTC (12:04 to 13:04 PDT)
h1lsc0 --- 19:16 to 20:06 UTC (12:16 to 13:04 PDT)

Though all relevant channels (ADC_0_30,  ADC_0_31, DAC_0_15) are free on the h1lsc0 front end, we elected to turn the DAC DuoTone off, so that we aren't in danger of an oscillitory analog voltage being sent around the IO chassis that's used to measure the OMC DCPDs.

Data and analysis to come. 

The IFO will be staying down for a few hours, while we finish up some electronics chain characterization of the OMC DCPD analog electronics (along with some other parasitic commissioning measurements).

C. Cahillane

I have managed to use ER7 data produce preliminary carpet plots of frequency vs. strain magnitude and phase based on the Uncertainty Estimation paper T1400586.
The code that generates these plots may be found here: /ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/S7/Common/MatlabTools/strainUncertainty.m

Darkhan recently did a similar study to this looking at error in magnitude and phase of Delta_L_ext when kappa_C, kappa_A, and f_c changed.  
My study currently looks at the error in magnitude and phase of strain when the magnitude and phase of kappa_tst and kappa_pu vary, as well as kappa_C and f_c.  (Recall that in general kappa_tst and kappa_pu can be complex.)

Right now I believe there is a serious error in the code, because the plot of the optical gain (plot 5) and the plot of the cavity pole (plot 6) show there is absolutely no error in strain even if these values differ greatly from the expected value.  The cavity pole varies by up to +- 100 Hz and does not vary by more than 1%.  The result is robust: I have calculated the strain using two independent methods and still I get these odd results.  These are my results right now, and this is why I call these plots preliminary.

I do believe the magnitude kappa_tst (plot 1), phase kappa_tst (plot 2), magnitude kappa_pu (plot 3), and phase kappa_pu (plot 4) plots look sensible.  Any phase in kappa_tst is generally intolerable for high frequency phase information, while phase in kappa_pu yields high error in low frequency phase information.  Since we do not expect any phase component at all in kappa_tst and kappa_pu, this makes sense.
Also, the magnitude of kappa_tst and kappa_pu must be tracked carefully at high and low frequency respectively.  10% errors in these magnitudes are enough to give more than 9% errors in strain magnitude.

Note that these results use ER7 data (GPS_start = 1116990382).  I'll soon be able to get ER8 data when it is all available (go calibration week!)

I have created a DTT template that makes it easier to decide when it's okay to turn on more OMC DCPD whitening.

Evan wrote an alog some time ago about the new OMC DCPD whitening on/off guardian states (alog 20578), and Cheryl and Evan made some notes on when it's okay to go to these new states (alog 20787).

As of right now, the guardian will automatically turn on one stage of whitening, but we get better high frequency noise performance if we add a second stage.  However, if some mode (eg. a violin mode) is rung up, then we can't add the second stage of whitening without being in danger of saturating the ADC.  So.  The new DTT template should help decide when it's okay to add the second stage.

The template is /ligo/home/ops/Templates/dtt/DCPD_saturation_check.xml (screenshot below). The template should be run after we have arrived at NOMINAL_LOW_NOISE for the main lock sequence.  If the dashed RMS lines are below the green horizontal line, it's okay to add the second stage of whitening.  

To engage the second stage of DCPD whitening:

Open the full list of guardian states for the OMC_LOCK guardian, and select "ADD_WHITENING". It will take a minute or two, and automatically return to the nominal "READY_FOR_HANDOFF" state.

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...

Patrick, Sheila, Jenne, Eric

For the first part of the test, we injected our fiducial CBC waveform (same one used in ER7) and tried raising the LIMIT value on the hardware injection block in order to address saturation problems observed in ER7. During ER7, the LIMIT was 200. We raised it to 400. The first injection did not go through:

1124601535 1 1.000000 cbctest_1117582888_		intent bit off, injection canceled

Patrick, Sheila, and Jenne tried to turn on the intent bit, but there was some sort of problem, which will be alog'ged separately. As a temporary work-around, we turned off the tinj intent-bit check and injected again:

1124602724 1 1.000000 cbctest_1117582888_		successful

Patrick determined that the injection produced a maximum |amplitude| of 15 counts coming out of the injection block, which seemed to indicate that the original LIMIT value of 200 was sufficient. However, an alarm went off to indicate that there was saturation at ETMY. Thus, the saturation problem cannot be solved by tinkering with the INJ block in MEDM. Rather, the problem is occurring downstream on the ETM actuators. We request that Jeff K, Adam M, et al. look into options for avoiding saturation at the ETMs.

Next we tried a blind injection using the new blind injection code. The blind injection code does not log injections in EPICS so they are not automatically picked up in the segment database.

1124603111 1 1.000000 cbctest_1117582888_		successful

The blind injection was clearly visible. The ETM saturation warning went off again. The injection was logged correctly in the blind injection blindinj_H1.log:

current time = 1124603049...
Attempting: awgstream H1:CAL-INJ_BLIND_EXC 16384 /ligo/home/eric.thrane/O1/Hardw
areInjection/Details/Inspiral/H1/cbctest_1117582888_H1.out 1 1124603111
Injection successful.

All of these injections were carried out with scale factor = 1; (that's the 1.000000). The injection file, described in a comment below, is a 1.4 on 1.4 BNS, optimal orientation, at D=45 Mpc. It is the same waveform used in previous ER tests.