Progress on the E X Wind Fence. We will continue work on this project today also.
Carl, Terra, Rich A.
1. We used the never-before-tested LVLN ITMY ESD driver to ring up and damp two mechanical modes of ITMY, 15072 Hz and 14979 Hz. Below is the amplitude evolution of the 15072 Hz peak as we rang it up, allowed it to ring down naturally, rang it up again, and then damped it down fully with a gain sign flip.
We drove and damped similarly for the 14979 Hz peak. 15072 Hz is the vertical differential drumhead mechanical mode; 14979 Hz is the horizontal version. For both cases, we tightly bandpassed the H1:OMC-PI_DCPD_64KZ_A/B signal, added a +60deg damping filter, and added gain to the damping filter until saturation. Positive gain drove up, negative damped down.
I've fit the natural ring down with f(x) = a * exp(bx), where tau = - (1/b). Then Q = pi * 15072 * tau = 31.5 million.
2. Interestingly, we realized after the above tests that we had not turned the ESD bias on for either ITM. After turning on both to 100K cts (to DC offset), we just had time to ring back up the ITMY 15072 Hz mode before a lockloss. Below is a comparison of the ring ups (note we lost lock and did not damp for the ring down portion below). Green trace is the 15072 Hz ring up without bias, blue trace is with bias (time shifted for ease of comparison).
A slight slope difference is visible but we'll look into this more. Thoughts are that we could use the difference in responses to measure test mass charge coefficients as discussed here and here.
3. We turned ring heaters off and on for future mode-mass identification analysis. For the record (since RH messing with violin modes was a concern tonight):
We were also driving the ITMX mode at 15077Hz before and after the bias was turned on. The data is a little more confusing. As the phase was being varied before hand to try find the optimum damping phase. In the plot the amplitude is made to coincide when the damping phase with no bias had the largest response. There was no attempt to optimise the phase in the case where the bias was on other that to try the positive and negative of the previous 'best' phase. Interesting points are:
For the 15077Hz mode the phase that excited the mode was flipped whent he bias was engaged.
The response with the bias engaged is relatively larger when compared to the ITMY 15072Hz mode.
For the 15077Hz mode the amplitude response with bias is about twice the amplitude response without bias.
Mode identification.
In the attached plot the relative change in frequency of the four likely drum head modes around 15200Hz is plotted as a function of time. The ring heaters were adjusted as follows:
ETMX 0.5W per segment to 0W 02:29
ETMY 0.5W per segment to 0W 03:00
ITMX 0W to 0.5W per segment 03:33
ITMX 0.5W per segment to 0W 04:02
ITMY 0W to 0.5W per segment 04:06
ITMY 0.5W per segment to 0W 04:36
The response in frequency shows that the 15218Hz mode is a cooling ETMX, 15219Hz is a cooling ETMY, 15197Hz a heating ITMX and 15192 a heating ITMY mode.
As we were only operating at 2W input the signal to noise ratio of modes is a lot lower and many fewer modes are visible compared to Livingston measurements T1600141.
The following is the list of modes identified.
Measured Frequencies | Simulated Frequency | ||||||||
ITMX | ITMY | ETMX | ETMY | ITMX | ITMY | ETMX | ETMY | Shape description | |
6044 | 6042 | 6055 | 6054 | 6057 | 6054 | 6053 | 6053 | Butterfly | |
8162 | 8160 | 8161 | 8158 | 8194 | 8190 | 8189 | 8188 | Drumhead | |
9812 | 9809 | 9829 | 9831 | 9827 | 9827 | 9832 | 9832 | Drumhead | Vertical |
9860 | 9863 | 9881 | 9882 | 9879 | 9881 | 9885 | 9885 | Drumhead | Horizontal |
10415 | 10437 | 10434 | 10433 | 10432 | 3 point ripple | ||||
10423 | 10419 | 10428 | 10426 | 10462 | 10460 | 10463 | 10462 | Drumhead | |
12992 | 12988 | 12999 | 13000 | 13022 | 13026 | 13035 | 13036 | Drumhead | Differential |
15077 | 15072 | 15093 | 15096 | 15102 | 15103 | Drumhead | Horizontal | ||
15197 | 15192 | 15218 | 15219 | 15227 | 15227 | 15232 | 15231 | Drumhead | |
15540 | 15545 | 15541 | 15544 | 15544 | Drumhead | Vertical | |||
15627 | 15635 | 15632 | 15634 | 15634 | Drumhead | Horizontal | |||
19555 | 19553 | 19589 | 19588 | 19595 | 19594 | Drumhead |
Stefan, Nutsinee
A very quick summary: ITMY modes rung up tonight. All the damp settings has been changed. I suspect ETMX damp phase might have been changed as well. ITMX didn't seen to have a problem. We suspect the ring heater changed the violin mode frequency.
Below I attached a screenshot of what works on ITMY modes tonight.
We looked at the frequency of mode 8 last night, two nights before around GW151226 and after a O1 power ouitage (20151025 9UTC). (attached)
Two days ago the mode was heavily damped, so the frequency estimate might be a bit off. At any rate, all frequencies are within 3mHz (or 22deg of feed-back phase in the current band-pass filter). So we ough to be able to damp this mode consistently.
Chandra, Gerardo -Adjusted CP5 Dewar pressure regulator 1/4 turn CW to raise Dewar pressure (nominally at 15 psi). Will wait hours/days to see results. -Measured Dewar vacuum jacket pressure = 20 microns, satisfactory. -Magnehelic readout is noisy - jumps from 35-40 in. of H20, even when CP5 is in manual mode. -Manually tested full range of stroke of electronic actuator - looks OK. -Tightened actuator support/brace nuts along unistrut. -Noticed needle of valve has wiggle (more than CP6). Verified packing nut is adjusted properly and coupling nut and needle are fully threaded. So now we wait to see if adjusting pressure of Dewar has an impact.
Not able to trend - was sitting around 100% but maybe just big swing?
Sheila, Haocun
We had lots of locklosses today, and some were probably caused by the side OSEM driving of the beamsplitter M1, as shown in the figures attached.
(H1:SUS-BS_M1_MASTER_OUT_SD_DQ & H1:SUS-BS_M1_DAMP_T_IN1_DQ)
It seems to have happened again at 22:20:12 UTC June 15th
Tagging SUS and CDS.
Tonight I had a look at several other of these locklosses, and other than the one at 23:57:59 that Hoacun plotted, it seems mostly like the glitch in the side osem comes after the lockloss. Many of these locklosses seem to happen durring the CM board switching.
It does seem like it would be worth investigating this side osem issue, since we know that it causes at least some locklosses.
J. Kissel WP #5932 Today's model modifications come in three parts: (1) Independent Synchronized Oscillators for each isolation stage of the QUAD for calibration lines (2) Updated CAL-CS model with better demodulation scheme that spits out coherence and uncertainty (3) Changed all CAL-DELTAL and CAL-DARM channels to double precision and removed whitening Below are all the details. ------------- Part (1) In order push the PCAL vs. SUS actuation calibration line cancelling scheme for ER9/O2 forward (see T1600218 and T1600215), I've installed independent, longitudinal, synchronized oscillators in each of the UIM/L1, PUM/L2, TST/L3 stages of all of the QUAD models. See first attachment for screenshot of the QUAD OVERVIEW screen that now has the CAL_LINE block beneath every LOCK bank. Sadly, due to the recent split in QUAD library part models, I'd forgotten to add the needed EPICs channel for GPS synchronization to the ITMs. We'll install them tomorrow morning. I've committed the following new models: /opt/rtcds/userapps/release/sus/common/models/ Sending FOUROSEM_DAMPED_STAGE_MASTER_WITH_DAMP_MODE.mdl <-- Used in PUM/L2 stages Sending FOUROSEM_STAGE_MASTER_OPLEV_TIDAL.mdl <-- Used in UIM/L1 stages Sending QUAD_MASTER.mdl <-- Added EPICs record for GPS sync time on TST/L3 stage for ETMs and accordingly modified MEDM screens: M SUS_CUST_QUAD_ITM_OVERVIEW.adl A + SUS_CUST_QUAD_ISTAGE_CAL_LINE.adl D SUS_CUST_QUAD_L3_CAL_LINE.adl M SUS_CUST_QUAD_OVERVIEW.adl ------------- Part (2) In addition, as a continuation of the improvements to using those calibration lines to track changes in the DARM loop parameters, I've followed Joe's instructions (see LHO aLOG 26491) and updated the CAL-CS model to demodulate PCAL and DARM error signals at given frequencies and produce parameter estimates, coherence estimates, and even uncertainty estimates. Darkhan will be working on commissioning the infrastructure with Joe. ------------- Part (3) Finally, I've converted all of the calibrated DARM channels to double precision. *EXCEPT* for DELTAL_EXTERNAL, which is needed to display on the wall in the control room via DTT (which sadly, cannot yet handle double precision; see CDS Bug 1003). As a result, and as per Joe's advice I've turned OFF all dewhitening filters that condition the following (new) channels stored in the frames: H1:CAL-DARM_CTRL_WHITEN_OUT_DBL_DQ H1:CAL-DARM_ERR_WHITEN_OUT_DBL_DQ H1:CAL-DELTAL_CTRL_DBL_DQ H1:CAL-DELTAL_CTRL_PUM_DBL_DQ H1:CAL-DELTAL_CTRL_TST_DBL_DQ H1:CAL-DELTAL_CTRL_UIM_DBL_DQ H1:CAL-DELTAL_RESIDUAL_DBL_DQ We need to investigate if we're now happy with the signal fidelity without whitening or if we just need to re-assess the whitening. Again, I've retained single precision on H1:CAL-DELTAL_EXTERNAL_DQ, so its whitening filter remains ON.
J. Kissel, J. Betzwieser Joe called to let me know that I'd misinterpreted the fixed oscillator part that we chose to use (of the two; see T1600143). Turns out this version of the fixed phase oscillator automatically synchronizes to GPS time 0 (i.e. Jan 4 1980), so there's no need for the extra EPICs record input to the oscillator that specifies the GPS time. So, in opposition to what's said above, the ITM models are fine; we need to take the GPS EPICs record *out* of the ETMs. Will do so tomorrow.
J. Kissel All QUAD Models have been restarted sans EPICs record for synchronization (the ITMs needed a restart to absorb the removal from the L1 and L2 stage common library parts). MEDM screen has been updated as well. I've committed the following to the repo. /opt/rtcds/userapps/release/sus/common/medm/quad/ Sending SUS_CUST_QUAD_ISTAGE_CAL_LINE.adl /opt/rtcds/userapps/trunk/sus/common/models/ Sending FOUROSEM_DAMPED_STAGE_MASTER_WITH_DAMP_MODE.mdl Sending FOUROSEM_STAGE_MASTER_OPLEV_TIDAL.mdl Sending QUAD_MASTER.mdl
The ITMY PI path was measured during maintenance day driving from CDS and measuriung the quadrant outputs to the ESD. WP#5931
Specifically driving H1:SUS-ITMX_PI_OMC_DAMP_MODE2_DAMP_EXC, and measuring P2-P5 of D1600122 directly with an SR785.
Generally behaves well. The LR channel has slight excess noise (about twice the other channels) which is a ~65kHz signal. It goes away when the DAQ input to the box is removed. There was no evidence of the glitchy behaviour of ETMX LR channel.
Other than that it looks just like the ETMX. The electronics TFs slightly over estimating the HF voltages.
Anticipate running this pump for then next week or two.
I've started a test Conlog process on conlog-test-replica connecting to the same channels as the production Conlog process on h1conlog1-master.
Michael, Jim, Krishna
We had 20-40 mph winds for most of the day yesterday. In the evening we tested a couple of different ISI configurations at the Corner Station (ITMX, ITMY) and the End-Stations. We tested the following two configurations:
1. 90 mHz Blends on ST1 and no sensor correction (SC) on all test-mass chambers - The standard configuration used for most of O1 which works well in low microseism.
2. 250 mHz Blend and BRS SC on ST1 at the End-Stations and 90 mHz blends and no SC on ITMX, ITMY - The idea is to use the tilt-subtracted ground seismomter in feedforward more and rely less on the tilt-contaminated ST1 seismometer.
Quick Answer: The effect on some of the Interferometer channels we looked at was a small but uniform improvement of a factor of ~1.5 or so over the 90 mHz blend configuration. Near 0.1 Hz we were limited by ITMY chamber motion.
Details: The first attached pdf shows some of the Interferometer channels in Config 1 (Dashed) versus those in Config 2 (Solid) in units of ADC counts. The red line is equivalent to H1:DARM_CTRL_OUT_WHITEN_DQ which for some reason was not available today. The other three lines are some of the Angular Control Signals, all of which show small improvements. The second page shows the ASD of the wind-speed in both Configs showing that wind-speeds were comparable during the two measurements.
The second pdf shows data from some of the ISI local sensors. The first plot shows the ground motion near each chamber - note that the ITMY seismometer sits in the 'bier garten' which is far away from the walls of the building. Also shown are the tilt-subtracted super-sensor signals (dashed lines). It is worth noting that the secondary microseism becomes visible after tilt-subtraction and is consistent with what the ITMY seismometer measures. The next plot shows the CPS signals which at low frequencies, are representative of the motion of ST1. The combination (ETMY-ITMY)-(ETMX-ITMX) should roughly correlate with DARM_CTRL at low frequencies, since the translational ground motion is small below the microseism. The third plot shows the ST1 seismometer(T240) motion. In all these plots, notice that despite the apparently quieter ground motion, ITMY moves nearly as much as ETMY. This is also seen in the fourth plot - which shows the coherence of the DARM_CTRL with the various CPS sensors. ITMY shows significant coherence between 60 to 200 mHz.
I think this suggests that the ITMY seismometer may not be a good measure of the tilt of the ITMY chamber, which is closer to the walls of the building. Thus our assessment that the Corner tilts significantly less than the End Station may not be valid. But if ITMY seismometer acts as a nearly tilt-free seisometer we can use it for sensor correction just as we do at the End-Stations and gain another small factor of ~1.5-2 in low frequency DARM_CTRL.
(Richard, Gerardo)
Landed cables at rack and at the controller for annulus ion pump 525 (BSC5 AIP), gettind data now.
For future reference at the rack for both X-end and Y-end:
F37 ------- 011(+)
F38 ------- 012(-)
Added 231 channels. Removed 74 channels. (see attached) The following channels are still unmonitored: H1:GRD-TCS_ITMX_LOGLEVEL H1:GRD-TCS_ITMX_MODE H1:GRD-TCS_ITMX_NOMINAL_S H1:GRD-TCS_ITMX_REQUEST H1:GRD-TCS_ITMX_REQUEST_S H1:GRD-TCS_ITMX_STATE_S H1:GRD-TCS_ITMX_STATUS H1:GRD-TCS_ITMX_TARGET_S
Kiwamu, Jeff, Evan
The calibration group has known since O1 that Hanford (but not Livingston) has an anomalous loss of gain in the DARM optical plant at 10 Hz and below. This can be explained by 0.5° of positive (antispring) SRC detuning away from pure RSE.
The first attachment shows a loop-corrected pcal sweep from O1, calibrated into mW/pm. On top of this I have plotted my guess at what theory curve this corresponds to (from Rob Ward's thesis), using 700 W of beamsplitter power, an arm pole of 42 Hz, an SRM transmissivity of 37 %, a homodyne angle of 90°, and a one-way SRC carrier phase of 90.5°. (The theory curve is pretty much insensitive to variations in the homodyne angle at the few-degree level, and we know that the homodyne angle deviates from 90° by less than 3°, since we ran with 20 mA of dc offset light and there is less than 1 mA of contrast defect light.)
To test this, I took a new set of pcal sweeps at 10 W of input power, with several different SRC detunings. The result is shown in the second attachment, again with guesses about the theory curves. All are with 350 W of beamsplitter power, 42 Hz arm pole, 37 % SRM transmission, and 90° homodyne angle. 0 ct of SRCL offset corresponds to the green (90.8°) curve, –200 ct corresponds to the blue (90.1°) curve, and +200 ct corresponds to the red (91.5°) curve. The implied calibration (0.1 ct / pm for the SRCL error point) is consistent with SRCL OLTF budgeting. The fact that 0 ct of SRCL offset produces a nonzero RSE detuning is perhaps not surprising, since we have never had good angular control of the SRM.
With the list of items on our plate and the need to give more time to getting H1 ready for ER9, we did our darnedest to limit Maintenance Day to 4hrs today. Jeff helped from the Detector Engineer side, and Ed was recruited whenever the waves of activities were too much.
With Maintenance starting at ~8:00, we were complete by around 12:39pm. At this point, it was noticed that the Quads were pretty misaligned. I restored their pointing via Oplev trends, and then since there were big changes, I went ahead and performed an Initial Alignment.
Ops Note: Only issue with alignment was when doing the last step (SRC_ALIGN_OFFLOADED). For some reason, the IMC would break lock and Guardian would loop through this step repeatedly. Not really sure what the issue was here. Sheila & Jenne were notified of this.
Alignment took from 12:39pm - 1:44pm & then handed over to Commissioners.
A log of all activities are attached as a pdf (vs posted in this alog......thought of reducing alog real estate with the many lines of each activity during the day---input on preference on how Operators should post logs like this would be nice).
At 18:00 utc I decreased the LLCV valve setting to 18%, previous setting was 20%. Due to LN2 delivery today.
Added 300 mL H2O to the H1 PSL crystal chiller. There were no fault alerts on either chiller. Both canister filters appear clear.
Carl, Terra, Ross, Tega
Tonight we used the freshly installed LVLN ITMX ESD driver to ring up and damp two mechanical modes of ITMX, 15063 Hz and 15077 Hz.
After sorting out some phase settings, we drove the ITMX ESD close to saturation in a differential drumhead pattern. Negative gain rang up 15063 Hz. Flipping the gain sign to postive then damped this mode and rang up 15077 Hz. The amplitude plateaued as a the saturated drive signal approched a square wave. Figure below tracks amplitude of 15063 Hz and 15077 Hz (seen in OMC trans), with gain sign flip occuring around the 0.15 time mark.
Also attached is a spectrum of H1:OMC-PI_DCPD_64KHZ_A_DQ during no gain, negative gain, and positive gain times, i.e. on either side of the 0.15 time mark from the plot above.
At about 0.23 hours the gain was turned off and the mode rangdown. The fit to this ringdown indicates the mode has a Q factor of (omega_o)/(2alpha) = 1.2 million.
Settings: Power 1.9 W, DC bias 100k, butterworth BP filter, iWave bypassed, -60deg damp filter, damp gain 300,000.
Such a wonderful conclusion to the installation and commissioning of this system. Much thanks for the great support I received from all involved.
I suspect that 15077 Hz mode is an aliased 48923 Hz mechanical mode (64 - 15.077) kHz. The FEA gives an interesting mode at 48944 Hz (mode shape attached). Observation of the analog channel PSD on transmission is required to confirm if this is a case. The 15077 Hz mode is only 14 Hz above known 15063 Hz mode. I am not very familiar with linetracking filter but I assume that the two resonant lines 15063 HZ and 15077 Hz cannot be sufficiently separated and the signal with higher resonant peak will be eventuality phase-locked. It may be interesting to observe the transition from one mode to another. If this all is true you measured the Q-factor of one of the modes in the range were PI may also show up at higher circulating power than during O1. It looks to me that the 48923 Hz mode is very sensitive to off-center position of optical TEM00 (that's probably why can be seen on OMC) and can be used for centering of TEM00 on ITMs.
In the Q estimate 'f' was used in place of 'omega_o' introducing a 2 pi error. The corrected estimate of the Q factor of the 15077Hz mode is 7.4million.