The work in alog 31308 (which involved an h1oaf restart) took the TCS chillers down, which subsequently took the lasers down. Richard/Gerardo restarted the chillers and the lasers (~9:30am PT). After a bad restart of h1oaf which caused some confusion, the 2nd or 3rd restart was finally successful and the FE servos took over to adjust the laser temps/powers to nominal. Here's the notes we gathered from today which we will write in an ops wiki:
If h1oaf gets booted and the chillers go down, you only need to restart the chillers at the front panel and the lasers at the racks on the floor. The TCS settings come back up properly with the safe.snap. If the front end is not up yet, the SDF may show some stale setting diffs. Ignore anything in SDF until the FE is back up - most of these diffs will take care of themself as many are servos that do automatic adjustments.
Doh - 10:52am PT - h1oaf "just died" - CDS working on it...
As of 10:40PT, 18:40UTC
Work going on
Still to come:
I have rebuilt daqd fw on h1fw2 using a new ldas-tools build (2.5.2). This is the version in use at LLO and contains updated leap second tables. The plan is to compare the output from h1fw2 to h1fw0 and h1fw1 for a week and then migrate h1fw0 and h1fw1 to use the newer framecpp releases next week. In the mean time the daq status page will show differences in the frames between h1fw2 and the other frame writers. This is due to framecpp encoding a different version string in the frame file. Dave will update the daq overview screen to help minimize the differences. This is under workpermit 6303.
Trended LVEA pressure gauge readings over 60 days. We have seen a trend upward in the two new hot cathode ion gauges PT 170 & PT 180 on BSC 7 & 8. Last Tuesday we degassed both to see if that helps stabilize the readings (cold cathode gauges, PT 120B, 114B, 134B, readings in corner are either flat or trend down!). PT 140 is the one and only gauge measuring diagonal volume, and is also a new hot cathode ion gauge. It was reading pretty flat, until Oct. 10th when the temperature in LVEA was increased at 2B area (west corner) by around 1/2 degF. PT110 is a new hot cathode gauge on HAM 6.
WP 6287 Installed additional ADC in h1oaf0 I/O chassis, bus slot 2-8. 8:05 PST powered down h1oaf0 computer, I/O chassis. Installed new ADC and interface card. Powered down TCS AI chassis, powered up I/O chassis. Remotely started h1oaf0 computer, verified card was detected, powered TCS AI chassis back on. Out of CER at 8:25.
I have switched chillers at the corner station from Chiller 1 to Chiller 2. This is simply to try and distribute the run time somewhat evenly between the three chillers. Temperatures should remain the same.
Nutsinee, Stefan
As suggested by alog 31304, we set up a 26:74 mixed input matrix element for PRCL in the next lock:
POP_A_RF9_I to PRCL = 0.0091
REFL_A_RF45_I to PRCL = -849 (yes, a minus sign)
This gave us the expected additionbal slight improvement in PRCL sensing, see the attached plot.
Indeed, this auxiliary noise reduction seems to have given us a range increase of about 5% to 75Mpc.
More importantly though, suddenly the range seemed to be rock-sold, without any up- and down drifts - see the last hour in the attached range plot.
Still to do: PRCL FF & possible modulation depth increase.
After this first step the return will not be as big in terms of range, but the improvement in range stability by itself makes it worth the effort.
We put all this into Guardian (NOISE_TUNINGS), but we didn't test the Guardian yet (the interferometer was too steady).
This is a follow up comparing the ADC noise, the dark noise and measured spectra. ADC noise is about 0.005 cts/√Hz at the input of the filter module. The following table gives the ratio of dark to ADC noise and the ratio of measured noise to dark noise above ~20 Hz.
|
Photodiode Channel |
Whitening Stages |
Ratio dark/ADC |
Ratio |
|---|---|---|---|
| REFL_A_RF9 | 2 | ~10 | ~4/3 |
| REFL_A_RF45 | 1 | ~4 | >3 |
| POP_A_RF9 | 1 | ~2 | >3 |
| POP_A_RF45 | 1 | ~30 | >2 |
The strange gain ratio for the POP9/REFL45 combination is partially explained by a cts2V filter bank that is enabled in REFL45.
We did a final CO2 exploration at an input laser power of 25 W today. This was to fine-tune the CO2 settings that the operators have explored in the past weeks (31048, 30974).
In the end I set the CO2X power back to 0.3 W (which was recently set 31246) which gave us the highest BNS range. Not sure if the addition of the IMC WFS offset (31246) changes the story here.
[The test]
The TCS test started at around 19:14 UTC today. The interferometer has been locked for more than 10 hours at that point with an input laser power of 25 W. The CO2 settings before the test was [CO2X, CO2Y] = [300 mW, 0 W]. This is something Sheila set during the weekend (31246). Here is an imcomplete list of time lines.
In the above list, the letters in the square brackets correspond to the labels in the dtt spectra shown below. A trend of this test are shown in the first attachment. LOCKINs 1 and 2 were monitoring the coupling transfer coefficients from the PSL periscope PZT to DARM for pitch and yaw, respectively. The pitch excitation was at 441.3 Hz and the yaw was at 421.1 Hz.
[The results]
The DARM spectra from different times are shown below.
As the CO2X increased, noise around 350 Hz and 620 Hz decreased. This behavior is qualitatively consistent with what I have seen in the LOCKIN demodulators, especially the yaw coupling or LOCKIN2. However, obviously, this improvement came with higher noise elsewhere. In particular, the 260 Hz peak became quite noticeably worse by a factor of 3 at most. Also, the side lobe of the 1 kHz violin modes became significantly worse too by a factor of roughly 2. This time, I did not check laser noise couplings (intensity or frequency) simultaneously. According to the sensmon shown in the first attachment, increasing CO2X decreased the BNS range by 5 Mpc or so. The DARM spectrum below 100 Hz seems to have stayed the same throughout the test.
J. Kissel
I've taken the first round of all swept sine measurements typically done before an observing run:
(1) Sensing function, C
(a) DARMOLGTF and Loop Suppression (IN1/IN2 and IN2/EXC); G and 1/(1+G)
(b) PCAL2DARM (and PCAL2DELTAL); (C/1+G) and [m/m]
(2) Actuation Function, A
(a) L1 to DARM & associated PCAL2DARM; (C A_uim)/(1+G) and (C/1+G)
(b) L2 to DARM & associated PCAL2DARM; (C A_pum)/(1+G) and (C/1+G)
(c) L3 to DARM & associated PCAL2DARM; (C A_tst)/(1+G) and (C/1+G)
where I've taken a separate PCAL2DARM or C/1+G transfer function with every corresponding excitation to destroy any covariance that had plagued us during O1. Also, I've worked to
(i) reduce the template's measurement time by maximizing drive,
(ii) reducing the number of points over all, and
(iii) keeping integration time in check,
such that each template only takes about 15 minutes. I've also modified the frequency vectors of the actuation functions to go out to 1 kHz, as LLO did for their O1 data sets. In doing so, I made sure to use frequency points that avoided any known high-frequency resonances from wire violin modes (characterized in LHO aLOG 24917).
There's still some improvements to make, which I'll shoot for in the next round (so don't use/take these templates as cannon yet), but thanks to the high-duty cycle of the IFO, I had the opportunity to make really well-balanced templates tonight.
The data lives here:
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/ER10/H1/Measurements/
(1a) DARMOLGTFs/2016-11-07_H1_DARM_OLGTF_4to1200Hz_fasttemplate.xml
(1b) PCAL/2016-11-07_H1_PCAL2DARMTF_4to1200Hz_fasttemplate.xml
(2)
FullIFOActuatorTFs/2016-11-07/2016-11-07_H1SUSETMY_L1_iEXC2DARM.xml
FullIFOActuatorTFs/2016-11-07/2016-11-07_H1SUSETMY_L1_PCAL2DARM.xml
FullIFOActuatorTFs/2016-11-07/2016-11-07_H1SUSETMY_L2_iEXC2DARM.xml
FullIFOActuatorTFs/2016-11-07/2016-11-07_H1SUSETMY_L2_PCAL2DARM.xml
FullIFOActuatorTFs/2016-11-07/2016-11-07_H1SUSETMY_L3_iEXC2DARM.xml
FullIFOActuatorTFs/2016-11-07/2016-11-07_H1SUSETMY_L3_PCAL2DARM.xml
While it'll be days before we have a model and a complete, traceable uncertainty budget, preliminary results show the *mean* of *one measurement* of PCAL's estimated displacement agrees with the front-end calibrated sensitivity to roughly 5% and 5 [deg]. This confirms that the > 50 Hz discrepancies between PCAL and DELTA L EXTERNAL seen while we were at 50 [W] (e.g. LHO aLOGs 30391 and 30431) were likely a function of the poorly controlled signal recycling cavity, and therefore time-dependent RSE cavity pole that was quite low.
Recall that the uncertainty of the PCAL estimation is around 1%.
We're right on schedule, and things are looking up. We'll see how the modeling goes...
DARM actuation spectra are attached.
We could do a bit better in offloading the microseism control from the PUM to the UIM.
SRC1 loops (P&Y) are ON Input Power Mean: 23.5 [W]
I succeeded in switching PRCL over to REFL_A_RF45_I.
This improved the sensing noise between 30Hz and 100Hz by about a factor of 2.
We did this in the middle of an earthquake, and eventually lost lock, so I didn't put it in Guardian yet. We also had more than usual scattering due to the earthquake, so it is too early to tell whether it made a DARM noise difference.
Also:
- We should investigate increassing (or better: not reducing) the RF45 modulation index.
- By mixing POP_A_RF9_I and REFL_A_RF45_I to PRCL by about 0.26:0.74 we should get another ~25% shot noise reduction.
- The first lock looked promising, but if for some reason we still have a DC drift problem on REFL, we could blend it to POP_A_RF9_I at DC
Matrix elements:
replaced the old
POP_A_RF9_I to PRCL = 0.035
with the new
REFL_A_RF45_I to PRCL = -1147.5 (yes, a minus sign)
J. Kissel The duty-cycle has been delightfully high, so we've been able to get the two hours needed for 1001.3 Hz data point of the roaming high-frequency calibration line quickly despite this mornings issues (see LHO aLOG 31288). Thus, I'm changing it to the much more time intensive 4 kHz line. Here's the latest status: Frequency Planned Amplitude Planned Duration Actual Amplitude Start Time Stop Time Achieved Duration (Hz) (ct) (hh:mm) (ct) (UTC) (UTC) (hh:mm) --------------------------------------------------------------------------------------------------------------------------------------------------------- 1001.3 35k 02:00 39322.0 Nov 11 2016 21:37:50 UTC Nov 12 2016 03:28:21 UTC ~several hours @ 25 W 1501.3 35k 02:00 39322.0 Oct 24 2016 15:26:57 UTC Oct 31 2016 15:44:29 UTC ~week @ 25 W 2001.3 35k 02:00 39322.0 Oct 17 2016 21:22:03 UTC Oct 24 2016 15:26:57 UTC several days (at both 50W and 25 W) 2501.3 35k 05:00 39322.0 Oct 12 2016 03:20:41 UTC Oct 17 2016 21:22:03 UTC days @ 50 W 3001.3 35k 05:00 39322.0 Oct 06 2016 18:39:26 UTC Oct 12 2016 03:20:41 UTC days @ 50 W 3501.3 35k 05:00 39322.0 Jul 06 2016 18:56:13 UTC Oct 06 2016 18:39:26 UTC months @ 50 W 4001.3 40k 10:00 39322.0 Nov 12 2016 03:28:21 UTC 4301.3 40k 10:00 4501.3 40k 10:00 4801.3 40k 10:00 5001.3 40k 10:00
Plot 1 shows the ASC coherence during an imperfect A2L strech this morning. this resulted in a power-law increase in DARM below 60Hz.
We designed slightly more agressive cut-off filters for DHARD_P, CHARD_P and CHAD_Y. They , take the ASC signal below other noise above ~35Hz, even if the A2L tuning runs away a bit.
Plot 2 shows the the new (sold) and old (dashed) drive levels of the ASC.
The new filters were integrated with the ELP10 filters for DHARD_P and CHARD_P (FM4 and FM2 respectively). For CHARD_Y I copied the cut-off filter from FM9 to FM3 before modifying it in FM3. This preserves the old 40W cut-off filter. I switched Guardian over to use FM3. The new filter uses less than 7deg extra phase at the UGF. The last 50W transfer function measurment suggest that we have about 60deg at the UGF, so the filter should also work at 50W.
The ISC guardian was again checked into SVN after the modification.
Coherence tool results from Oct.31 to Nov.7
The 11Hz comb is very pervasive. It is found in 255 channels in the second week Oct.31 - Nov.7. In some of the channels, the comb only has the lower 3 or 4 harmonics. The results are posted here:
https://ldas-jobs.ligo-wa.caltech.edu/~duo.tao/O2_lines/index.html
Rick S, Sudarshan K, Travis S, Jeff K, Darkhan T,
We uploaded the updated force coefficients (N/V) into the PcalY filter file. This has effect on following calibrated outputs:
H1:CAL-PCALY_TX_PD_OUT*
H1:CAL-PCALY_RX_PD_OUT*
Calculation of the factors is described in T1600520-v1. Relevant sources (other T documents containing WS, GS and end-station calibrations) were referenced in that document. The Matlab script that produced the factors is attached to the document above and also can be found in CalSVN (or a newer version of the script in the same directory):
https://svn.ligo.caltech.edu/svn/aligocalibration/trunk/Projects/PhotonCalibrator/scripts/pcalEndstation/pcalForcecoefficient.m
The old and new values are listed below:
One can notice that these values are nearly identical, which is a mere coincidence. We consider PCALY is now in a new epoch w.r.t. O1 time because we adjusted beam positions on the ETM (also addressed clipping at RxPD integrating sphere) and we adjusted the angle of the transmitter module beamsplitter which adjusts the power balance between the two beams (see LHO alog 30877).
The PMC length noise no longer shows up in DARM. Even for the 1 kHz and 4 kHz peaks there is a factor of a few safety margin. Increasing the PMC gain slider from 0 dB to 16 dB (actually from 0 dB to 12 dB), we see no significant change in DARM. The 4 kHz peak starts touching the noise floor with a 0.3 coherence.
This means that the increased coherence between DARM and jittery peaks after the increase in the modulation depth and associated PMC changes (alogs 31095 and 31203) is a mystery.
We are running about 8dB higher PMC length gain than before as that's the lowest we can go with the current electronics with higher modulation depth. It would be interesting to see if modifying the electronics will do anything.
(In the attached, IMC_F and IMC-WFS traces are scaled arbitrarily such that it's easier to make an eyball comparison.)
J. Kissel, D. Tuyenbayev We're still not getting the IFO duty cycle to get the desired uncertainty on the single-frequency actuation strength scale factor measurement of the UIM and PUM stage and we're running out of time, so I've increased the SNR of these temporary lines by another factor of ~3 over yesterday's increase (see LHO aLOG 31108). Oscillator Freq (Hz) Old Amp (ct) New Amp (ct) ETMY UIM 33.7 180 500 ETMY PUM 34.7 81 300 Hopefully Robert's activities tonight won't impact the ~30 Hz region of the sensitivity, and we can turn things off soon.
Jeff K, Darkahn T,
We calculated actuation strengths of L1 (UIM), L2 (PUM) and L3 (TST) actuation stages using calibration lines from 6 lock stretches in the last two days.
Preliminary results are given in the attached plots. Standard deviation on estimations of AU and AP are ~1.2% and for AT is ~0.4%.
Data points were taken at GPS times with HOFT_OK_BIT = 1 (segments are listed below).
# seg start stop duration
0 1162123790.0 1162124750.0 960.000
1 1162124840.0 1162125190.0 350.000
2 1162125280.0 1162125480.0 200.000
3 1162127120.0 1162129210.0 2090.000
4 1162134280.0 1162137150.0 2870.000
5 1162162170.0 1162163370.0 1200.000
Increased line amplitudes will hopefully allow us to get AU and AP actuation strengths with subpercent 1-sigma error bounds.
Jeff K, Greg M, Darkhan T,
After the L1 and L2 line amplitude increase it seems that we got better uncertainties in the esitamtions of the sus. stage actuation strengths.
This time we filtered the data using the IFO range channel, we used 50 MPC as a threshold. And from the remaining data we made historams of three different time intervals. We did not yet investiage why the noise levels of the lines are different at each of these intervals. The uncertainties for A{U,P,T} are given for the least noisy interval (blue data points).
Jeff K, Greg M, Darkhan T,
We calculated [N/ct] actuation force factors calculated from the ~35 Hz independent L1, L2 and L3 lines:
KU = 8.012-8 +/- 3.873-10 N/ct ( std(KU) / |KU| = 0.0048 )
KP = 6.482-10 +/- 2.748-12 N/ct ( std(KP) / |KP| = 0.0042 )
KT = 4.253-12 +/- 1.679-14 N/ct ( std(KT) / |KT| = 0.0039 )
During a Nov. 4 lock stretch we got a factor of 3 improvement of the standard deviations compared to the previous day (blue data points vs. green).
In most recent 2 days we got more data with longer lock stretches, which can help us to better bound the uncertainties. Analysis of this data would require including an updated DARM digital filters, the IFO response changed on Nov. 5 (see LHO alog 31201) which can bias on our calculations if not taken into account.
The outliers were removed in a following way:
- Took >= 50 MPC data and removed data points that fall outside of 2-sigma std. deviation (some large outliers were not filtered by this step);
- one more time calculated std. and mean in the remaining data points and removed 2-sigma outliers (this step helped to remove large outliers).
- The mean and 2std. of these data points were shown with black solid line and dashed lines.
The final reported mean values and standard deviations were taken from the blue data points ( GPS [1162252470, 1162271230] ), L1 and L2 data was least noisy during this period. This mean value and its std. were shown with blue solid and dashed lines.
A while ago we saw that negative 400 volts reduced the 60 Hz line in DARM by a factor of 2. (30778)
We just checked again and this is still true and now the guardian will set in the guardian state low noise etmy esd. We are doing this using the gain in the bias filter bank so that the bias choosen to mitigate charge will still be use whenever we aren't locked.
Tagging a few extra groups to make this entry more visible. The 60 Hz harmonics are still a factor of ~2 lower. Nice discovery!
Started yesterday evening. Doesn't seems to be equally spaced.
It could be pickup through the unshielded part of the RTD cable (where it comes out of the laser), but it's strange that it started in X and Y at the same time. Can you check the FLIR cameras are turned off on the MEDM screen.
Apparently there is a "glitch" in the laser power of both X and Y TCS systems every time the Laser power meter sees a request for a power change. (see 1 day trend with additional channels to correlate with). However, this did not just start yesterday, it has been going for at least a month (see second plot of the last 3 days). I spot checked back a month and the behavior is the same. Note, there are a few extra spikes on these channels but this doesn't seem to be new behavior.
Update: I looked closer at these glitches.
Characteristic:
A single glitch spans across multiple sample points, lasted a little less than half a second. Almost everyone of these glitches lead by one smaller glitch that's roughly 1.5 second apart, followed by an even smaller glitch and immediately followed by a larger glitch.


Timeline:
I looked back several months and it seems like these glitches started to show up much more frequently on May 13th this year (started at 16:28 UTC to be precise). I looked back on the alog and didn't find any invasive work with the TCS on May12th or 13th.
