M. Coughlin, K. Venkateswara

Michael noticed the earthquake on October 14th (M7.3 off of Nicaragua) was nicely visible in the seismometers and the BRS. I have attached the timeseries plots. I've also attached ASD plots of about 2 hours of data during the earthquake. GPS time = 1097293900.

The first ASD plot shows the T240X and the BRS RY out signals. Our guess for the horizontal displacement coupling was about 2e-4 rad/m. Multiplying this number with the T240 displacement output gives the red curve in the second plot. This seems to explain the signal in the BRS very well. The plot also shows the approximate estimate of the expected tilt signal assuming

theta ~ (2pi/wavelength) * X  

where wavelength = velocity / frequency (assuming sound velocity of 5 km/s). This gives the light blue curve, which is a factor of ~5 below the displacement coupling in the 50-100 mHz range.

The third plot also shows the residual between the BRS RY out and the displacement coupling which is close to the light blue curve, but without knowing the displacement coupling in an independent measurement, we cannot estimate the tilt component. The fourth plot shows the coherence between the two instruments.

This is a good confirmation of the expected horizontal displacement coupling in the BRS and a measurement of the distance between the COM and the pivot, which appears to be 30 +/-5 micrometers. If |d| had been <3 micrometers, this would have enabled a direct measurement of the tilt component of earthquakes.

no restarts reported.

Lisa, Rana, Evan, Sheila, Chris, Kiwamu,

The DRMI was stable tonight. So we did several attempts for reducing the CARM offset and the smallest we got tonight was 125 Hz in IR. We will performe careful analysis of lock losses tomorrow.

Lock loss events to lock at are: 7:59:30, 8:11:09 and 8:56 UTC. The second one reached 200 Hz in IR and the last reached 125 Hz. We decreased the MICH gain from 7.9 to 3.0 because its UGF was found to be too high when the arm cavities were held at a off resonant point. According to the lockin demodulators, all the loops stayed without a significant gain change or anything. ALS COMM seemed to tend to lose its lock when it is "IR FINE TUNE". We need to investigate what causes lock losses.

As requested by Jim, I loaded the filters in BS HEPI and then ran the Switch_To_Test.py for setting the BS ISI to the test configuration at around 9:05 in UTC or 2:05 in PDT. Note that the oplev damping loops are running.

Peter F, Rana, Kiwamu,

As a preparation for the full lock study, we experimentally tried adjusting good coefficients for decoupling MICH from the other two in the LSC output matrix. Here are the results.

• MICH --> BS = 1.0
• MICH --> PR2 = 0.02
• MICH --> SR2 = -0.014

Precision for the PR2 and SR2 coefficients seem to be roughly a few %  and 10 % respectively.

(Adjusting coefficients using the realtime lockin oscillators and demodulators)

We used the LSC realtime lockin oscillators and demodulators to find out the good output matrix for MICH. We drove BS at 131 Hz with an amplitude of 1000 cnts. At first, in order to find out the coefficient for removing PRCL out of MICH, we locked the sideband PRMI. We shook the M2 stage of both BS and PR2 in the longitudinal while changing the coefficient for PR2 manually until in-phase signal vanished at REFLAIR_RF45. We, of course, assumed REFLAIR_RF45 to be well tuned in its demod phase. Before the measurement we copied BS's inversion filter over to PR2 such that their frequency responses as seen from the LSC frontend are identical. In PR2, all other filters should be off and gain should be just unity. 

Moving onto DRMI, we then shook PR2, BS and SR2. The coefficients for PR2 and BS were set to 1.0 and 0.02 so that we shake MICH more purely. Experimentally adjusting the coefficient for SR2, we found it to -0.014. The sign is negative because the effect of BS onto PRCL and SRCL are different and therefore it makes sense. We don't know why the PRC and SRC coefficients are different by 40% or so.

(Some tricks in SR2 M2 stage)

So for the setup in SR2, since one of the coil actuators had been dead, we used only LL and UR coils such that they still actuate without a large cross-couplings to the angular degrees of freedom at a cost of losing the half of actuation efficiency. This factor of two was then compensated in the Euler matrix by increasing them by a factor of two. We also copied the same BS inversion filter to SR2.

Rana, Kiwamu, Lisa, Alexa, Sheila, Evan

We took some time to measure the 1f and 3f DRMI sensing matrices.

To do this, we used the digital lock-in oscillators on the LSC screen to feed back onto some of the DRMI optics (PR2, SRM, BS, and a combination of 1×BS + 0.02×PR2 that we refer to below as BS+PR2).

The procedure was as follows:

1. In the first digital oscillator lock-in matrix, we wired REFLAIR9I→DEMOD 5, REFLAIR9Q→DEMOD 6, REFLAIR45I→DEMOD 7, and REFLAIR45Q→DEMOD 8. Each demod had an 0.1 Hz Butterworth filter.
2. For each demod, we made all the power appear in I by running, e.g, cdsutils servo -r LSC-LOCKIN_1_DEMOD_5_Q_OUTPUT -g -10 -s 0 -t 100 LSC-LOCKIN_1_DEMOD_5_PHASE.
3. For each optic in turn, we enabled the oscillator in the output matrix. We then turned on a 131.7 Hz oscillator excitation whose amplitude was 15, 3333, 1999, and 1999 counts for PR2, SRM, BS, and BS+PR2, respectively.
4. We monitored the four demod I channels in StripTool. Then we used z avg -s 8 to average them.

Results for the 1f sensing matrix are as follows. The drive amplitudes have been divided out (and the entire matrix normalized).

The matrix elements for SRM (in red) are probably bogus, because we were saturating the SRM actuator while driving.

Then we repeated this for the 3f signals, with REFLAIR27I→DEMOD 11, REFLAIR27Q→DEMOD 12, REFLAIR135I→DEMOD 13, and REFLAIR135Q→DEMOD 14. The drive amplitudes were 15, 9333, and 1999 counts for PR2, SRM, and BS. The results are as follows. Again the drive amplitudes have been divided out (and the entire matrix normalized).

DRMI lost lock before we were able to get the BS+PR2 measurement for 3f.

It seems as though an oscialltion in the BS (visible on the stage 2 GS13) caused a DRMI lock loss.  The oscillation seems to be in the ISI channels, but I don't see it in the control signals or on the OpLevs.

I've set up a script to turn on the RH on ITMY around 2:30AM for 3 hours. To kill it if desired, either log in to operator1 and kill the tmux process, or just turn off the RH after it turns on.

J. Kissel

I attach pictures of the switchable configuration boards of all optical levers in the corner station. My fingers are supposedly indicative of the rack / chassis into which they're plugged, but I add a legend here anyways with the real rack numbers, and I include the exact switchable filter status. Note, I only report one of the channels' switch status, because (thank god) in every instance, all four channels are configured in the same way.

Rack          Board      Optical Lever    Config Board  |------------------ Switch Status ----------------|    Centered?  Raw Segment Counts
              Number                       Installed?    Board    Switch                                        
                                                        CH Name   CH Name    Function    HI   LO    ON/OFF        
SUS H1-R1       1        HAM2 Table?          No          N/A                                                  (HAM2) No     1:-339 3:-2243
  (Pg 1)                 HAM3 Table?                                                                                         4:-399 2:-3548 

                2        HAM2 Table?          No          N/A                                                 (HAM3) Maybe   1:-1260 3:-1167
                         HAM3 Table?                                                                                         4:-1921 4:-1594
                                                                                                                            
SUS H1-R2       1          none?              No          N/A                                                     N/A
  (Pg 2)
                2           PR3               Yes          B0       1       +24 [dB]     X            OFF      PR3 Yes-ish   1:-5600  3:-7400
                         (pgs 3-5)                         B1       2       +12 [dB]          X       ON                     4:-17800 2:-17500
                                                           B2       3       +6  [dB]          X       ON                
                                                           B3       4       +3  [dB]     X            OFF
                                                           B4       5       (1:10)            X       ON
                                                           B5       6       (1:10)       X            OFF
                                                           B6       7       (1:10)       X            OFF
                                                           B7       8       Latch        X            OFF
                                                              Total PR3 TF = (1:10), G = 18 [dB]

SUS H1-R4       1        HAM4 Table?          No          N/A                                                  (HAM4) No     ADC Noise
  (pgs 6-7)              HAM5 Table?

                2        HAM4 Table?          No          N/A                                                  (HAM5) No     ADC Noise
                         HAM5 Table?

SUS H1-R3       1           none?             No          N/A                                                  N/A
  (pg 8)                               
                2            SR3              Yes          B0       1       +24 [dB]     X            OFF      SR3 Yes-ish   1:-9100 2:-9200
                          (pgs 9-10)                       B1       2       +12 [dB]     X            OFF                    4:-7040 3:-9200
                                                           B2       3       +6  [dB]     X            OFF                   
                                                           B3       4       +3  [dB]     X            OFF
                                                           B4       5       (1:10)            X       ON
                                                           B5       6       (1:10)       X            OFF
                                                           B6       7       (1:10)       X            OFF
                                                           B7       8       Latch        X            OFF
                                                              Total SR3 TF = (1:10), G = 0 [dB]
                
SUS H1-R6       1            BS               Yes          B0       1       +24 [dB]     X            OFF      BS  Yes-ish   1:-6800 2:-6300
  (pgs 11)                 (pg 12)                         B1       2       +12 [dB]          X       ON                     4:-7250 3:-7350
                                                           B2       3       +6  [dB]     X            OFF                   
                                                           B3       4       +3  [dB]          X       ON   
                                                           B4       5       (1:10)            X       ON
                                                           B5       6       (1:10)       X            OFF
                                                           B6       7       (1:10)       X            OFF
                                                           B7       8       Latch        X            OFF
                                                              Total BS TF = (1:10), G = +15 [dB]

                2           ITMY              Yes          B0       1       +24 [dB]     X            OFF      ITMY Yes-ish  1:-2470 2:-2380
  (pgs 15)               (pg 16-20)       (NOT AS SHOWN)   B1       2       +12 [dB]     X            OFF                    4:-2250 3:-2900
                                                           B2       3       +6  [dB]     X            OFF                   
                                                           B3       4       +3  [dB]     X            OFF   
                                                           B4       5       (1:10)       X            OFF
                                                           B5       6       (1:10)       X            OFF
                                                           B6       7       (1:10)       X            OFF
                                                           B7       8       Latch        X            OFF
                                                              Total ITMY TF = (flat), G = 0 [dB]

SUS H1-R5       1           ITMX              Yes          B0       1       +24 [dB]     X            OFF      ITMX Yes-ish  1:-1000 2:-700
  (pgs 13)                 (pg 14)                         B1       2       +12 [dB]     X            OFF                    4:-1000 3:-700
                                                           B2       3       +6  [dB]     X            OFF                   
                                                           B3       4       +3  [dB]     X            OFF   
                                                           B4       5       (1:10)            X       OFF  
                                                           B5       6       (1:10)            X       OFF
                                                           B6       7       (1:10)       X            OFF
                                                           B7       8       Latch        X            OFF
                                                              Total ITMX TF = (1,1:10,10), G = 0 [dB]

Note that I've left ITMY with all of its switches OFF because we want to assess whether the internal gain of the QPD head (see D1100290) is set to the "high" (100 [kOhm] transimpedance) or "low" (10 [kOhm] transimpedance) -- and I got booted out of the LVEA for locking the IFO. Seems like 2000 counts is a little to low, we really want something like 10000 [cts] per quadrant. We will adjust tomorrow.

I've also confirmed that all over-all transfer functions for each optic has digitally compensated for correctly.

Continuing a  trend of stealing from LLO without shame, I looked at the L1 ISI foton  file (via LLO's DAQ svn) to see what filters they were using for St1 sensor correction. I've attached some plots comparing some of the filters. It would be helpful if someone at LLO could summarize (again) what is being used in a complete and accurate way, because some of the filters have very similar names. FF is a common name for different filters. In the first plot, the green (I think) line is the sensor correction a version of the filter Rich Mittleman designed, that we have been using at ETMX with the BRS. The other lines, with an rdr are Ryans filters that I found in the LLO ITMY foton file, which I named based on what direction I found them. Second plot is the phases of same filters, with the same color scheme and order.

zpk's for the different filters:

rdr X,Y & Z Senscor

zpk([0.005868986282643151+i*0.005869222531082809;0.005868986282643151-i*0.005869222531082809;0;0;0;
    0],[0.02121320343296193+i*0.0212131204375177;0.02121320343296193-i*0.0212131204375177;0;0;
    5.326821252114442e-10;0.03999999945769176;0.0999999989897627;1.299999570000159;
    6.999932741807108],6217465930.447066,"n")

rdr Y Senscor

zpk([0.006840399999901201+i*0.01879390059988029;0.006840399999901201-i*0.01879390059988029;
    0.06062180000003715+i*0.03500000003808696;0.06062180000003715-i*0.03500000003808696;0],
    [0.01368079999995818+i*0.03758769978878637;0.01368079999995818-i*0.03758769978878637;
    0.03500000000007082+i*0.0606217999686012;0.03500000000007082-i*0.0606217999686012;
    0.01000000066387688;0.03999999933609382],99.46935875676593,"n")

Mittleman Senscor

zpk([0.05785089999994956+i*0.06894400006181636;0.05785089999994956-i*0.06894400006181636;0;0;
    1.054942208843087e-09;0.009999998945009785],
    [0.003420200000103372+i*0.00939692986876447;0.003420200000103372-i*0.00939692986876447;
    0.01267849999986304+i*0.02718920009938821;0.01267849999986304-i*0.02718920009938821;
    0.04499510000006567+i*0.05362309993610679;0.04499510000006567-i*0.05362309993610679;
    0.005000000000048375],0.006161864174656091,"n")

rdr Z Senscor

zpk([0;0;0],[0.003535529999897033+i*0.003535531890194072;0.003535529999897033-i*0.003535531890194072;
    0.000868241000053361+i*0.004924041464289278;0.000868241000053361-i*0.004924041464289278;
    50.0000000000001],252959718.8553666,"n")

08:00 resarted Alarm Handlers; CDS overview: noticed some conflicting counts on fw1 and some timing flags at the mid station; Vacuum: noticed IP-01 flashing red. Sent out emails to the corresponding folks for a check-out.

08:30 ISS loop coming in and out of saturation. Diffracted power all over the place. I bumped the refsignal up a click and the diff power stabilized. I tried a series of clicks following and got the diff power back up to ~7.6%  

09:09 Betsy and Travis out to West bay to work on 3IFO Quad.

09:10 Andres out to W Bay

09:20 Peter F out to LVEA

09:55 J Bartlett, also Andres out of LVEA

10:25 Ryan reported a possible network outage lasting ~10 minutes maybe upstream of PM&L

? Alastair putting power meter on TCS X arm table (WP 4925)

11:12 Robert working in beamtube between mid Y and end Y (shaking tests)

11:21 Dan to end X to look for equipment

11:56 Shivaraj to end X and end Y to mount magnetometers on tripods

12:38 ISS first loop went erratic again until ~

13:19 Karen at end Y

13:51 Karen out of end Y

14:30 Dan H out to HAM6

15:20 Rana brought to my attention folks entering VEA areas. Not everyone is reporting their desire to enter to the operator. Cleaning personell are calling after they've arrived at end stations.

As a first step towards a fast shutter at the AS port, I swapped the QPD transimpedance amplifier box for ASC-AS_C for one with the SUM output spigots for the shutter input.  From rack R5 slot 20:

Out: S1102836

In: S1301506

I also changed the P3 jumper on the OMC PZT LV driver board to the correct position (across pins 2 & 3).  Now, a 0V input to the 'shutter logic' input on the front of the OMC PZT driver box is recognized as a 'fault' condition (i.e., with 0V input, the PZT shutter function is triggered).  This draws the PZT1 drive down to 0V (from 10V).  It also pretty well disables the dither output to PZT1, so no OMC locking until we connect the PZT shutter input to a 5V supply (like, for example, the shutter logic controller on top of ISCT6).

It looks like the ASC-AS_C sum is about the same as before the swap, but we probably need to redo the dark offsets.

J. Kissel, R. Abbott

Was checking the status of the ETMX optical lever against Doug's status report (see LHO aLOG 14711) before I took some measurements using it, and found that the ETMX optical lever's compensation filters (i.e. H1:SUS-ETMX_L3_OPLEV_SEG?) have to filters, "gain2" and "gain1.4" (which are gains of 0.5 and 0.707, respectively) that are turned ON. I couldn't find any aLOGs about these filters, and it doesn't really make sense to me to compensate for any analog gain, given that we normalize by the SUM.

Anyone know anything about this?


%%%%%%%%%% EDIT %%%%%%%%%%%
Doug's status chart reports values exactly backwards and bit-shifted up 1. "HIGH" bits are LO, and "B1" = B0. The confusion arised from Evan's convention for high vs. low, and that the switches are numbered starting at 0 on the board, and 1 right next to the switch. Therefore, the ETMX is compensated for correctly. 

Will post corrected assessment shortly.


%%%%%%%%%% Historical Log, for future reference %%%%%%%%%%%%%

Piecing together the puzzle, from Doug's aLOG (LHO aLOG 14711), and the various circuit schematics (Configuration Daughter Board D1001631, Chassis Assembly, ), Evan's recent PR3 tune up (LHO aLOG 14631), my aLOG from many moons ago (LHO aLOG 3619), and a phone call to R. Abbott, I can determine that having each channel in the following configuration (as indicated by Doug's aLOG, where B0-B7 is the configuration for the first channel, and the remaining 3 channels, B8-B15, B16-B23, and B24-31 are in the same configuration),
Switch     Function       Setting    Status
 Name                     HI   LO   
  B0      G = 24 [dB]           X      ON
  B1      G = 12 [dB]           X      ON
  B2      G = 6  [dB]      X           OFF
  B3      G = 3  [dB]      X           OFF
  B4      1:10 Whitening        X      ON
  B5      1:10 Whitening   X           OFF
  B6      1:10 Whitening        X      ON
  B7      Latch                 X      ON
Note -- and this seems to be a common misconception -- when the switch is LO (or "0", or away from the chassis as installed) the switch is ON / ENGAGED. Therefore, the total transfer function: G = 36 [dB], two stages of (1:10) whitening.

(filter zero and pole notation is (z:p) -- note that the poles and zeros is INCORRECT [i.e. inverted] in my old aLOG)

Thus, the current compensation scheme, with FM1 (10:1) with FM4 and 5 (the "gain" filters mentioned above), it seems as though the switches have been interpreted in exactly the opposite fashion as the schematic intends. Even worse -- the LATCH is ON, which means it's actually telling the board to engage whatever the settings were *before* the latch were engaged, and the current status of the bits B0 through B7 DON'T MATTER. #facepalm

Will get with Rana / Evan / Doug / Jason about this.

Observing the many trips HAM2 has experienced using the guardian recently, I've seen that after the first group of dofs are isolating, the remaining dof error points often grow large and when these dofs gains are ramped up, the ISI trips with a rung up GS13.  I saw that the guardian was loading the reference locations between the dof groups engagement.  Whereas the old seismic command scripts would only load the reference locations after all the dofs are isolating at the free hanging position.  Remember, the command script was not having any trouble turning the isolation back on.

Jamie modified the Guardian to do the loading of the reference location at the end of the isolation process like the command scripts.  When I got my window to test this, I actually forgot at first to restart the guardian.  And, the first couple times guardian was able to bring it up!  When I realized it wasn't doing it the new way, I remembered the restart, but I kept trying the guardian.  On the third or fourth attempt with the guardian it tripped.  I then restarted the guardian and then the guardian was successful at full isolation at least 6 times before the commissioners returned to the control room.

So again, my theory is, when the isolation loops are servoing to a place away from the free hanging position, the uncontrolled dofs error points can grow large.  This is dependent on many thing and lots of luck good & bad.  When the loop is engaged at low gain, the error point may be swinging about zero and if the loop gain is changed to 1.0 (from 0.01) at an unlucky time, bam goes the GS13.

Currently, HAM2 ISI is successfully back under Guardian conrol.