Screenshot attached shows the camera images with the IMC input beam at 2W, and the gain of 4000 on both GigE1 and GigE2.
Change in SR3 M2 OSEM values: LL change is 3x larger than any other OSEM
| UL = -1.5 | UR = -4.1 |
| LL = -112.7 | LR = 35.5 |
OSEM vales: the difference in yaw may be effecting the OSEM changes
| UL = 11503 | UR = 8203 |
| LL = 10913 | LR = 6597 |
Plot of the OSEMs attached.
After the lockloss, PRMI didn't look good at all, so ran an Initial Alignment.
Locking hasn't been fruitful so far, and the violin modes continue to be a culprit as was experience after Maintenance Day yesterday. Have had a few chances to work on them, and so far have been focusing on ETMx AND ETMy.
First attempts were at DC Readout, but at this point they are rung up pretty bad.
Now looking at violin modes at the SHUTTER_ALS state. Fundamentals have been up around e-13.
Have had locklosses while trying to damp. Not sure whether it's because I'm missing other violin resonances while damping others.
Oh, and have also had the ETMx UL (i.e. ETMX_BIO_L2_MON) come up in an OFF state after last few locklosses (to clear/reset, one enters a 1.0 for the UL RMS RESET field & then take it back to 0.0).
This seems like a new feature since I was last on shift.
Currently riding through either a Chile or Japan earthquake....whoops!
As I was typing H1 went down at 11:06utc. (but I don't think it was an EQ since I don't see anything in tidal signals or on the ISI_CONFIG medm---will thus remain in the WINDY state.)
TITLE: 07/26 Owl Shift: 07:00-15:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Observing at 53Mpc
OUTGOING OPERATOR: Ed
CURRENT ENVIRONMENT:
Wind: 12mph Gusts, 11mph 5min avg
Primary useism: 0.01 μm/s
Secondary useism: 0.07 μm/s
useism has drifted down over the last 24hrs to the nice doldrums.
QUICK SUMMARY:
Ed gave me the run down of where we are at. Will keep an eye out for violins. And will address A2L if L1 drops out of OBSERVING.
DARM spectra continues to look noisy post MT-quake (i.e. big table from 10-16Hz & then slightly elevated from 25-1kHz) & have had a few glitches in the opening minutes of this shift.
While performing round of walking the building (mainly turning off lights), a few notables:
TITLE: 07/26 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 54Mpc
INCOMING OPERATOR: Corey
SHIFT SUMMARY:
LOG:
05:59UTC Livingston was contaced and confirmed alert. INJ_TRANS is doing it's thing. 1Hr to go
After a rather lengthy violin mode damping period, H1 is back in Observing @ 55 Mpc. ETMY mode 5 was succesfully brought below the e-15 goal that was to be the threshold for continuing to power up. There were no issues. I returned the gains on the violin modes that I had worked so hard to damp back to the settings that I had used to do so. I accepted these changes in the SDF and took screenshots of everything that I "accepted" to clear for Observing. Please see attached images.
It looks like the matrix for ETMY violin mode5 (508.22 Hz)had its matrix changed on July 17th to actuate on length instead of pitch. Ed tells me operators have had difficulty damping this mode recently. I tried switching the matrix back to pitch and have been able to slowly damp the mode using a positive gain and no phase shift.
Keita and I have again changed the matrix back to actuating length, we are now using a gain of positive 20 and +60 degrees for damping, but progress is very slow
Beverly, Josh
The pitch drift value of several quad and triple optics (especially ETMX, ETMY, ITMX, ITMY) changed substantially (e.g., 200urad for ETMX) during the 6 July 2017 Montana EQ and the change persisted for most of them. A list of Summary Page links to the pitch drift for most of the optics on 6 July is given below. The attached table of images includes the actual graphs (middle column) along with the same quantity on 4 July (first column) and 25 July (3rd column) to check for persistence. Note that the actual transition is visible on 6 July, the day of the EQ. On days before and after the EQ, there is not much change within a given day but the numbers on the vertical axis indicates the qualitative value of the pitch drift.
The trends for ETMX pitch, yaw, and vertical are shown in Figs. 1-3. Pitch changes significantly but the yaw and vertical do not.. Note that the quake time is 2017-07-06 06:30:16.5 UTC, or 2 days 6:30 on the plots in Figs. 1-3, which is quite consistent with the pitch jump.
Links to Summary Page of pitch drift on 6 July 2017 for the indicated optics:
BS: https://ldas-jobs.ligo-wa.caltech.edu/~detchar/summary/day/20170706/plots/H1-ALIGNED_3A59D6_TIMESERIES-1183334418-86400.png (small change)
ETMX: https://ldas-jobs.ligo-wa.caltech.edu/~detchar/summary/day/20170706/plots/H1-ALIGNED_57EB46_TIMESERIES-1183334418-86400.png (big change)
ETMY: https://ldas-jobs.ligo-wa.caltech.edu/~detchar/summary/day/20170706/plots/H1-ALIGNED_EB31EB_TIMESERIES-1183334418-86400.png (big change)
ITMX: https://ldas-jobs.ligo-wa.caltech.edu/~detchar/summary/day/20170706/plots/H1-ALIGNED_12F173_TIMESERIES-1183334418-86400.png (big change)
ITMY: https://ldas-jobs.ligo-wa.caltech.edu/~detchar/summary/day/20170706/plots/H1-ALIGNED_ABFA9C_TIMESERIES-1183334418-86400.png (big change)
MC1: https://ldas-jobs.ligo-wa.caltech.edu/~detchar/summary/day/20170706/plots/H1-ALIGNED_ABFA9C_TIMESERIES-1183334418-86400.png (small change)
MC2: https://ldas-jobs.ligo-wa.caltech.edu/~detchar/summary/day/20170706/plots/H1-ALIGNED_94968B_TIMESERIES-1183334418-86400.png (large change)
MC3: https://ldas-jobs.ligo-wa.caltech.edu/~detchar/summary/day/20170706/plots/H1-ALIGNED_41B596_TIMESERIES-1183334418-86400.png (large change during EQ but seems to have reverted to pre-EQ value)
PRM: https://ldas-jobs.ligo-wa.caltech.edu/~detchar/summary/day/20170706/plots/H1-ALIGNED_F79514_TIMESERIES-1183334418-86400.png (small change)
SRM: https://ldas-jobs.ligo-wa.caltech.edu/~detchar/summary/day/20170706/plots/H1-ALIGNED_9E8930_TIMESERIES-1183334418-86400.png (moderate change)
TITLE: 07/25 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Aligning
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
Wind: 10mph Gusts, 8mph 5min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.08 μm/s
QUICK SUMMARY:
TITLE: 07/25 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Aligning
INCOMING OPERATOR: Ed
SHIFT SUMMARY:
LOG: Usually busy Maintenance Day, started initial alignment around 1:30 local and then the struggle began. While lock green arms, it would seem to be locked nicely for a handful of minutes, then Y arm would just unlock. I would redo the process and get the power up near .7, turn on the WFS, and then the power would drop down to near nothing a bit later. I got Jeff and Sheila involved at this point we would watch error signals and would close the WFS one by one to see what what happening, but have not come to a good conclusion yet. Handing off to Ed.
J. Kissel, S. Dwyer, T. Shaffer
We'll debugging the Y-ARM alignment during initial alignment, we went back to the camera archive,
/ligo/data/camera/archive/${YYYY}/${MM}/${DD}
and found -- comparing against the live camera -- that the mask that is used to calculate the centroid for the ITM green camera is poorly aligned with the green spot on the camera.
This is just a note that we should fix this once we're happy with an alignment that gets the IFO back up.
SudarshanK, PaulM
Summary:
We moved the Pcal beam spot on EndX by about 8 mm in y direction such that the beams are close towards the center of the optic from their optimal position of +/- 111.6 mm.
Details:
We moved the inner (top beam) using the last steering mirror on the Tx module and moving the mirror mount screw clockwise in pitch. We were able to get the Pcal beam close to our desire location with about a quarter turn of the screw. The beam came out on the receiver side without clipping in vacuum but the receiver side optics had to be adjusted to get the beam into the RxPD.
For outer beam (bottom beam) we moved the beam by moving the mirror mount clockwise in yaw. We were not able to get the entire beam out of the vacuum when Pcal beam was moved to the desired position. We have no way of knowing if the clipping is happening on the way to the ETM or the way out from the ETM. We didn't feel comfortable (on Rick's advice) to translate the beam to relieve the clipping. We are hoping the beam is clipped on the way out and we can use the TxPD signal to calibrate the displacement. We will be able to figure this out once we have a locked interferometer by comparing the displacement measured by the interferometer and predicted by the Pcal photodetectors (TxPD in this case).
This new Pcal beam position will introduce a calibration error on hardware injection at a level of 2% at 2 kHz and much smaller at lower frequencies. However, if the clipping is happening on the way to the ETM this will introduce significant error not only on hardware injection but the study that I am trying to do so we will have to come up with a plan to relieve the clipping.
The position of the Pcal beam spot before and after are as follows:
| Before | After | |
| Upper Beam | [1.9, 0.3] | [2.5, -8.4] |
| Lower Beam | [-1.0, 0.3] | [-1.3, 8.6] |
Also, the injection of high frequency lines are scheduled using the Guardian as described in alog 37765. The frequencies we will be running are: [5001.3, 4751.3, 4501.3, 4251.3, 4001.3, 3501.3, 3001.3, 2001.3]
TITLE: 07/25 Owl Shift: 07:00-15:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Preventive Maintenance
INCOMING OPERATOR: TJ
SHIFT SUMMARY: After the initial lockloss of the shift, I have been unable to get past REDUCE_RF45_MODULATION_DEPTH without OMC DCPD saturations. After the first couple of locklosses at this point, I went stepwise through each guardian state from DC_READOUT_TRANSITION. While watching the ISC_LOCK log at REDUCE_RF45_MODULATION_DEPTH, it seems that the CHARD P loop never really converges. It vacillates between converged and waiting for convergence. If you select any higher guardian state, it will immediately move on when it registers converged and OMC DCPD saturation alarms start. SRC1_Y error signal on the StripTool starts running away from zero once the DCPD saturations start. Performed IA after 3rd lockloss during relocking; did not help. ETMy violin mode 5 has been an unresponsive nuisance during this saga, but I can't say for sure that it is entirely responsible.
On the bright side, PCAL X RX PD seems to have fixed itself at the lockloss from the step at another lockloss reported in alog 37726. See attached screenshot.
LOG:
Prior to 13:20, see Shift Summary above.
13:20 Called Keita for help
14:25 Lockloss while Keita was working to remove OMC whitening. We decide to forego trying to relock since maintenance day is starting in 35 minutes.
14:51 JeffB to diode room, then to cleaning area
14:59 JeffK starting TFs on BS and PR3
To operators:
The reason why I wanted to remove whitening was because OMC DCPDs were railing for whatever reason (violin?). As soon as DCPD starts constantly railing it becomes hard to damp violins and PI (Travis had a hard time taking care of PI).
I tried to manually punch in 0 to PDB gain and 2000 to PDA gain quickly enough but it took me longer than I wanted, IFO didn't like it.
I could have written a script to do it quicker, but JeffK later showed me that you can do it in the guardian.
Open OMC_LOCK, then ALL, then MANUAL, then REMOVE_WHITENING (or ADD_WHITENING), and get back to MANAGED.
Another note (July14th) for REMOVE_WHITENING steps when violins rung up (with note about Manager of OMC_LOCK node): here.
J. Kissel
Still hunting for what's limiting our range, we took Valera's suggestion to drive stage 2 (ST2) the test masses' BSC-ISIs to check for, among other mechanisms,
(a) scattered light problems,
(b) charge coupling issues, or
(c) mechanical shorting / rubbing
The measurements indicate that ETMX and ITMY are the worst offenders, in that their ambient noise falls as ~1/f^{1/2} between 10 and 100 Hz, with some resonant features at 70 and 92 Hz. The features are presumably the first few cage bending modes, for which we have Vibration Absorbers that have already knocked down the Q of the ~70 Hz modes, thankfully.
I've used the measurements to "calibrate" the error point of the ISI's ST2 Isolation Loops, and project the ambient noise to equivalent DARM displacement noise (a.k.a. primitive noise budgeting), see first attachment.
Each come within a factor of 3-5 at their worst parts during ambient conditions; too close for comfort.
Also, of course, there should be no such coupling at all if the cage were properly isolated from the suspension, and this appears to be a straight-forward linear coupling.
Note that the precision of the projection is not great -- I did not try hard to get it right. There are addendum plots that show the residual between model and measurement.
I don't think this is a / the limiting source now, since there is little coherence during ambient conditions, but this will certainly be a problem in the future if the coupling remains this bad for ETMX and ITMY. It definitely deserves a more careful calibration, further study with other degrees of freedom, and mapping out a broader frequency band. Perhaps we should check the coherence with these ST2 ISI channels after Jenne's subtraction of jitter (see LHO aLOG 37590) -- though the slope doesn't quite match up (from eye-ball memory).
ITMX's coupling is about 1/2 as bad, and ETMY does not show any visible signs of bad coupling at this excitation level (which is damning evidence that it's related to charge, since ETMY has the largest effective bias voltage at the moment).
%%%%%%% Details %%%%%%%%
Measurement Technique (all while in nominal low noise):
- choose obvious, simply to imagine coupling degrees of freedom: the longitudinal axis for the optics in the arm cavity (X for ETMX and ITMX, Y for ETMY and ITMY)
- measure ambient error signals in those directions using DTT.
- In the same DTT template, create a band-passed excitation where you suspect you're having problems (10-100 Hz), shape it to look roughly like that ambient spectra you see. I used
ellip("BandPass",4,1,40,10,100)zpk([0.1],[1; 10],1,"n")gain(0.159461)gain(1e-4)
copied and pasted to the 4 excitation banks (thanks Daniel!) so that I can pick and chose what I'm driving, and with what amplitude.
- Grab a bunch of relevant response signals; the excitations, the error signals, the calibrated displacement (the pre-calibrated SUSPOINT signals are especially nice -- though the suffer from spectral leakage up to above 10 Hz).
- Slowly creep up the drive (I started with 0.001 [ct] to be extra careful) until you start to see hints of something / coherence.
- In case the coupling is non-linear, record the results at three different drive levels (I chose factors of three, 500 ct, 1500 ct, and 4500 ct, filtered by the above band-pass.)
Analysis Techniques
- Remember, to calibrate DELTA L EXTERNAL, one must apply the transfer function from
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O2/H1/Scripts/ControlRoomCalib/caldeltal_calib.txt
i.e. copy and paste that file into the "Trans. Func." tab of the calibration for the channel, after creating a new entry called (whatever) with units "m".
- For calibrated transfer functions of ISI displacement in local meters to DELTA L in global differential arm meters, just plot transfer functions between SUSPOINT motion (which comes pre-calibrated) and DELTA L EXT.
- Store the transfer function between the ISI ST2 ISO error point and DELTA L EXT for the loudest injection
- For "good enough" calibration of the error point, make a foton filter (in some junk file) that looks like the transfer function of error point to DELTA L EXT, and install into DTT calibration for that channel. Guess the gain that makes the driven error-point spectra line up well with the DELTA L spectra. For ETMX this was
foton design: resgain(70 Hz, Q=8, h=8) * resgain(92 Hz, Q=30, h=10) * zpk(100,1,1)
equiv zeros and poles: z=[10.6082+/-i*69.1915, 3.42911+/-i*91.9361, 100], p = [4.2232+/-i*69.8725, 1.08438+/-i*91.9936, 1], g = 1
dtt calibration:
Gain: 1e-14 [m/ct]
Poles: 4.2232 69.8725, 1.08438 91.9936, 1
Zeros: 10.6082 69.1915, 3.42911 91.9361, 100
For ITMY this was the same thing, but without the 92 Hz resonant feature:
foton design: resgain(70 Hz, Q=8, h=8) * zpk(100,1,1)
equiv zeros and poles: z=[10.6082+/-i*69.1915, 100], p = [4.2232+/-i*69.8725, 1], g = 1
dtt calibration:
Gain: 1e-14 [m/ct]
Poles: 4.2232 69.8725, 1
Zeros: 10.6082 69.1915, 100
This calibrates the channel, regardless of if there's excitation or not (assuming all linearity and good coherent original transfer function) --- in the region where your transfer function is valid, then this will calibrate the ambient noise.
Since I didn't take enough data to really fill out the transfer function, I only bother to do this in the 10-100 Hz, and did it rather quickly -- only looking for factors of ~2 precision for this initial assessment.
So as to not confuse the main point of the aLOG, I'll attach supporting plots as a comment to this log.
I attach support plots that show
For each test mass: The DELTA L EXTERNAL spectra during excitations, along with calibrated displacement of each excitation, the resulting transfer function, and coherence.
For those who may have to repeat the measurement, I attach screenshots of the DTT configuration and what channels I used explicitly. The template's too big to attach, but it lives in
/ligo/home/jeffrey.kissel/2017-07-242017-07-24_BSCISI_ST2_BB_Injections.xml
Also, shown for ETMX and ITMY, the projected ST2 Error Point both under excitation and during ambient conditions, with the residual transfer function shown below to expose how poor the calibration is.
Jeff and I added his data to the simple noise budget. We are still using a pre-EQ darm noise in this plot, and you can see that the couplings he found explain some of our unexplained noise around 60-70 Hz.
Adding a couple plots to show that ETMX ST2 coherence to CAL_DELTAL has changed, but measured motion doesn't seem to have changed. First plot is the coherence for 500 averages from the long lock on June 22, 2017 from 18:00 UTC on (in blue) to a similar window from the lock last night (red). The lump at 70-ish hz in red is new, not visible in the pink trace from June. Second plot shows the ST1 L4Cs and ST2 GS13s (both in meters) for the same periods (the June measurement is red and blue, last night are green and brown). The ST2 motion especially is nearly identical around the lump at 70 hz. Talking to Sheila, this maybe implies that scatter at EX is worse now than before.
I looked at all of the other BSCs as well for the lock segment last night, but none of the them showed the same coherence as ETMX.
For the record, here are two alogs from LLO on tests we've done:
BSC injections before O2 (when we found the problem with ITMY). We plan to repeat these before the end of the run.
O2 HAM injections (all clear to at least x10 above ambient).
If we are making a budget of the stage 2 motion to DARM then we should take into account the rotation motion also, since the bottom of the cage has ~2 meter lever arm
For off-site interested parties, I've committed the above template to the seismic repository here:
/ligo/svncommon/SeiSVN/seismic/BSC-ISI/H1/Common/Data/2017-07-24_BSCISI_ST2_BB_Injections.xml
and corresponding key to all of the 100+ references in the template (as well as documentation of measurement times) is in the same location, with a similar name:
/ligo/svncommon/SeiSVN/seismic/BSC-ISI/H1/Common/Data/2017-07-24_BSCISI_ST2_BB_Injections_ReferenceNotes.txt
I've replotted some of Jeff's data for the stage to beam direction drive to Darm and added a plot from Ryan and Valera's (24820) similar data.
There are the four stage 2 motion to Darm transfer functions from H1 (I made the ETMY data dotted because it has no coherence)
There is a 1/f^2 line (light blue) which is what you might expect for the coupling from a charged path on the test mass to a moving charge (not quite a matching slope, but the transfer function phases all look like 0 degrees)
I wasn't able to recover transfer functions from the LLO data so I plotted the amplitude ratio for the one platform where there is excess signal in Darm (ITMY in green). The vertical black lines mark the limits of where there is excess signal and where you can believe that we have a decent estimate of the transfer function. The sensitivity on the other LLO chambers is much less (at least a factor of 5)
One more plug for a rotation measurement, a good measurement of the rotation to Darm transfer function on ETMX and/or ITMY would let us do some geometry to guess at the height of the coupling location (again assuming a point like integration between the cage and the suspension cage)
