distance from the PSL table to the acoustic enclosure wall = 4' 10-11/16" distance from acoustic enclosure wall to periscope face plate = 2' 9" The face plate is labelled as IO ALS M5.
Sudarshan, Thomas, Darkhan, Travis, Rick
At 104.7. Hz the displacement DARM ASD was 1.26e-16 m/rtHz , the ASD according to the Pcal line was 2.07e-16 m/rtHz. The ratio is 1.64, with Pcal reporting a higher ASD.
We were running the Pcal calibration line at 104.7 Hz at LHO ENDY (25000 cts. excitation amplitude) during the lock stretch
After calibration of the power going to the test mass using the Working Standard at Yend and using the radiation pressure induced displacement equation
x= 2*P*Cos(theata)/M*c*(2*pi*f)^2
we have calculated (preliminary) the calibration value for the Transmission Monitor photodetector to be
x= 1.68e-12 (1/f^2)*(m/V)
Attached is the calibrated plot of Pcal ASD together with the DARM ASD in the region near the calibration line.
Found one of the channels for PEM AA chassis at EX (CH24) has an offset of about ~1500cts. Will pull unit on Tuesday to troubleshoot.
The attached plot shows coherence between a microphone in the electronics bay and DARM. It may be worth investigating acoustic coupling to the electronics.
Posted below are the OpLev 12 hour trends.
At GPS time 1107854779 [2015-02-13 09:26:03 UTC], H1 appeared to unlock but the ISC_LOCK guardian state didn't change. The attached plot shows the X-arm power and the guardian state to confirm (hopefully).
At the time of writing the guardian is still reporting 'DC_READOUT' as the current state, while there is no circulating power in the arms. The other guardian nodes (e.g. ISC_DRMI) did respond to the lockloss, however, so I presume it's just an oversight in the ISC_LOCK DC_READOUT state definition to check that the other guardians are still nominal, or that the arms are actually locked.
This should be fixed now.
I'm always a step behing the on-site commissioners (good job!), but here is the list of coherence for the 2+ hours lock:
https://ldas-jobs.ligo.caltech.edu/~gabriele.vajente/bruco_1107760396/
Here are my main comments on it:
Just realized that I ran the code on Livingston data instead of Hanford data! So these results are not meaningful... Sorry for the mistake!
All day next Tuesday will be scheduled for maintenance Model changes planned for next Tuesday Sheila and Richard will install a low pass filter box between the IO piezo controller and periscope PCAL was calibrated at end X yesterday PCAL may have a bad AOM at end X There is a request to label the analog camera images
model restarts logged for Thu 12/Feb/2015
2015_02_12 00:56 h1fw0
2015_02_12 15:33 h1fw1
2015_02_12 17:14 h1broadcast0
two unexpected restarts (first h1fw0 unexpected restart since 11 days ago). Broadcaster reconfigure for DMT channel addition. Conlog frequently changing channels report attached.
Dan, Jeff, Sheila
Tonight we had some more fun noise hunting. Turning the power up to 8 Watts was easy, but didn't improve the noise so much since we are mostly not shot noise limited.
This gave us a lower noise floor, we sat here from 5:28:10 UTC Feb 13th to 5:41:29 UTC, with the intent bit undisturbed.
We then made a single destructive attempt to reduce the ESD bias voltage, we'll have to come back to this. :)
On the next lock we decided to try increasing the input power. This was suprisingly easy, we have now been sitting at 8 Watts input power since 7:03:43 UTC. We have been adjusting the BS alignment by hand every 10-15 minutes or at 10 Watts. We have watched the AS36Q WFS signals while we do this, and can see that they are not always correct (zero does not always give us the best AS90). BS yaw dramatically improves the intensity noise coupling. It seems as though the IFO would stay locked like this all night if we sat here and adjusted the BS once in a while. We are leaving it locked and undisturbed.
In the attached plot, the green trace is earlier today, The blue trace is with 1 stage of DCPD whitening on and the ISS second loop on, which is injecting noise at around 700 Hz. The red trace is now, with 8 Watts input power, BS YAW oplev damping gain reduced, and the ISS second loop off. You can see that we are not really shot noise limited, as increasin the power by a factor of 2.8 only gives us a small improvement at high frequencies. Something is clearly wrong with the calibration.
The attached plot illustrates eight hours of progress today. (Times are approximate.)
At 3:30pm we were using the in-vacuum POP photodiode for MICH, PRCL, and SRCL.
At 9:30pm the violin damping ninjas had allowed us to enable one stage of whitening on the DCPDs. The ISS second loop was on for this lock stretch. During this lock the intent bit was set to OBSERVATION for about ten minutes (see times above), and ISC_LOCK Guardian was in the 'DC READOUT' state.
At 11:30pm we had increased the power from 2.8W --> 7.8W. But, we forgot to turn on the ISS second loop. Tweaking the BS alignment reduced the beam jitter coupling at 100-300Hz and around 700Hz. There is a lot of coherence above 1kHz with the LSC DOFs, we believe that we are not dark noise or shot noise limited in this region.
As we increased the power we changed the DARM offset, gain, and OMC scale factor & gain to maintain good phase margin. At 7.8W we could not incerase the DARM offset to provide ~16mA in the carrier mode at the OMC, the DCPDs would saturate from the violin mode. The last lock stretch had a DARM offset of 2e-5 and a DCPD sum of ~12mA.
We noticed the 1/f^3 noise between 30 and 70Hz was breathing on a several-second timescale. The noise here is somewhat coherent with MICH, we wonder if it is also due to ESD DAC noise or DAC zero crossing glitches. We have left the IFO locked in 'DC READOUT' with the intent bit set to observe. DetChar, please examine the data for glitches associated with major-carry transitions.
Glitch investigation: Keep in mind that there are about a dozen IPC erros per second on the controls signal sent to the ETMs.
The interferometer unlocked around 9:25UTC, so it stayed locked for more than 2 hours at 8 W. The plot shows a 14 hour trend from yesterday, with several hours of lock overall. Most of the unlocks were commissioning-related. (P.S.: still very quiet seismic environment).
Shot noise dominates the noise floor in kHz range, there was something wrong about the power scaling and/or scaling with DARM offset.
The first attachment shows that, in calibrated spectrum, the Pcal line in 7.8W (red) was a factor of 1.6 larger than in 2.8W (blue).
There should have been something wrong about power scaling somewhere, and if you want to make a fair comparison between 7.8W and 2.8W, 7.8W should be brought down by a factor of 1.6.
If you take this into account, 7.8W noise floor would be about a factor of 1.7 smaller than 2.8W for, say, f>7000Hz. (The top panel in the second attachment shows that 7.8W data is 5% or so smaller than 2.8W, and 1.6/0.95 = 1.7.)
sqrt(7.8W/2.8W)=1.7.
Further, in the same plot, the bottom and the middle panel shows that both in 7.8W (red, blue) and 2.8W (green, brown) the noise floor of DCPD SUM is very close to the NULL stream except for many structures, and PDB/PDA coherence is very low except these structures. (Also, in the middle pane of the second attachment, the black trace is the dark noise with high Z and 1 stage whitening, which is a factor of 5 smaller than 7.8W noise.)
Therefore we're confident that the noise floor for kHz range is already dominated by the shot noise.
Overall scaling is another problem which should be fixed separately.
I examined the sidebands of the OMC ASC dither lines today. The excess noise around these lines is disappointingly broad, roughly +/-2Hz. There are sidebands around the dithers at +/-0.18, 0.45, 0.49, and 1.5Hz.
The attached figure compares the sidebands of the first dither line (middle plot) to the low-frequency DARM noise (top plot). The bottom plot is the noise around the violin mode.
Sheila, Dan, Elli, Kiwamu, Lisa, Peter, Robert
Here is a calibrated DARM spectrum from today's DC-readout lock, using the new CAL-CS channel described in LHO#16698.
According to GWINC, the BNS inspiral range of this spectrum is 8 Mpc.
The calibration must be wrong, ignore this for now.
H1BROADCAST.ini was modifed to add the signal H1:DAQ-BCST0_CHANS_SAVED to the DMT. The DAQ broadcaster was restarted.
07:00 Karen and Cris in LVEA 08:06 Jeff B. turning off dust monitor 16 08:16 Bubba to LVEA to work on LN2 piping for LTS 08:17 Jeff B. done 08:29 Corey to squeezer bay for 3IFO work 08:35 Rick to end Y to check on Thomas and Sudarshan 08:39 Bubba done 09:12 Jim W. working on SEI BSCs 09:17 Alastair putting 3IFO equipment in cabinets in LVEA 09:47 Corey out of squeezer bay 09:48 Jim W. done 09:54 Robert to IOT2 and PSL enclosure 10:02 Travis back from end Y 10:05 Corey and Andres to LVEA 10:09 Corey back 10:13 Andres back 13:39 Filiberto to end X, not VEA, to read serial numbers and pick up tools 14:18 Filiberto done
Several people reported that the DARM calibrated signals from the OAF model did not look healthy in the past two or three days. Looking at the data in frequency domain, I confirmed that they have behaved funny. Cosulting with Jeff K, we decided to gradually migrate the functionality from OAF to CAL-CS model (alog 16669) because CAL-CS is going to be the official calibration place in future anyways. We are still in the process of moving from OAF to CAL-CS, but a calibrated DARM signal is now available in CAL-CS. The funny behavior seen in OAF is not seen in CAL-CS so far. The calibration accuracy is not yet examined.
(Bad OAF data)
Looking at the data in frequency domain, indeed they looked funny -- the spectral shape of, for example, OAF-CAL_DARM_DQ was suspiciousely featureless with the noise floor around 100 Hz much higher than it should be by a couple of orders of magnitude. Also it did not show a roll-off shape at 5-ish kHz for some reason. A confusing fact is that it sometimes looks behaving correctly and sometimes doesn't. I did not make a further investigation because we decided to move to CAL-CS.
(CAL-CS)
I copied the DARM-related filters that I had in OAF over to CAL-CS. So it is right now completely a duplication of what we had in OAF. I did not move the DRMI, CARM, or IMC filters yet.
Here is a brief summary of how the current calibration was done.
The current one relies on the reponse of the ALS DIFF VCO. Since we knew the VCO response in Hz/V, we were able to calibrate the ALS DIFF sensor into meters using the dx/ L = d(nu)/nu relatation. Then, by knowing the UGF of ALS DIFF, we calibrated the ESD coefficient in meters/counts. The last step is to calibrate the DARM optical gain by measuring the UGF in the final DARM loop.
I checked in the matlab code, which I used for the calibration, into svn. It is Runs/S7/Common/MatlabTools/LSC_DARM_calibration.m in the calibration SVN. For more details, please refere to the code.
H1:CAL-DELTAL_EXTERNAL_DQ is the new calibrated DARM signal. The signal is digitally whitened by five zeros at 1 Hz and five poles at 100 Hz.
