Calibration Measurements:

- Kiwamu, IFO down for calibrations, 9:05 - expected to be all day, continuing now

*** FYI, I move the IFO to Commissioning when this happened and should have been Calibrations - my bad.

Note; We are now in Calibration, so IFO has two states:

'"IFO is up'"  OR  "IFO is having calibration measurements run."

Today's parasitic IFO/site activities:

- JeffB to EY, dust monitor investigation, 9:07 - done

- Hugh to EX and EY, HEPI, 9:07 - done

- JeffK, ETMY, measuring coil drivers, 9:15

- Sudarshan, PEM channel check in LVEA, 9:20 - done

- TJ EX BRS reset - 9:54 - done

- Kyle, near EY (Y28) to gather stuff - done

- Dave, EX, drawing updates - 12:10 - done

- Kyle, near EY (Y28) to gather stuff, 12:54 - done

- more visits to end stations while there was the opportunity, but no changes, just monitoring or restoring equipment.

Currently no outstanding IFO issues.

Calibration measurements continue.

Stefan, Elli

On Saturday Stefan measured the AS36 signals with dither lines from the BS and SRM (alog 20777):

Lines:
H1:SUS-SRM_M3_ISCINF_P_EXC 7.0Hz, 300cts
H1:SUS-SRM_M3_ISCINF_Y_EXC 7.5Hz, 900cts
H1:SUS-BS_M3_ISCINF_P_EXC  8.0Hz, 100cts
H1:SUS-BS_M3_ISCINF_Y_EXC  8.5Hz,  30cts

Here are some plots of the AS36 signals demodulated against these line frequencies.  These signals  show how the sensitivy of the AS_36 WFS to the BS and SRM, which changes during the heat-up stage of the whole interferometer, and during 45MHz modulation depth reduction.  Attached are plots of the original and demodulated signals vs time.  Two vertical red lines are plotted; the first corresponds with when the IFO reaches full power, the second is when the 45MHz modulation depth reduction begins.  At the end of the time series the traces go crazy-  this is where Stefan reports lock was lost due to SRC1 yaw run away.

The following WFS channels are fed back to the optics at this point:
AS_B_RF36_I_PIT      >>   SRC1 PIT      (seen in demodulation of 7.0Hz line. Right two plots, red trace)
AS_B_RF36_I_YAW   >>   SRC1 YAW    (7.5 Hz line.  Right two plots, blue trace)
AS_A_RF36_I_PIT      >>   MICH PIT       (8 Hz line. Left two plots, red trace)
AS_B_RF36_Q_YAW  >>  MICH YAW    (8.5Hz line.  Right two plots, brown trace)

The SRC1 PIT signal doesn't change much, which is good.  SRC1 YAW has a 180deg ohase change during the heat-up stage.  Lines 1813 and 1815 of the guardian indicate a sign change in the ASC input matrix, maybe this corresponds to this phase change (?).  MICH PIT signal looks pretty good, getting close to 180deg phase at the end of the modulation depth reduction.  MICH YAW drifts downwards in phase, it looks like it hit -180deg just at the point we lost lock.

Following up to the problem (insufficient whitening) reported in  alog 20700,  new dewhitening filters  are implemented in the following DEALTAL_CTRL channels:

H1:CAL-CS_DARM_DELTAL_CTRL_M0/L1/L2/L3_WHITEN:  Original -- (zpk([1, 1, 1], [500,500,500],1,"n")

Changed to  (zpk([0.1,0.1,0.1,0.1], [100,100,100,100],1,"n")

H1:CAL-CS_DARM_DELTAL_CTRL_SUM_WHITEN: Original --(zpk([1, 1, 1,1,1], [100,100,500,500,500],1,"n")

Changed to  (zpk([0.1,0.1,0.1,0.1], [100,100,100,100],1,"n")

The first attached plot shows DARM CTRL signal with original filter in dotted  lines and the new filter  in solid lines.

The second plot shows the effect of different filter combinations on DARM_CTRL signal. This measurement gave us an intuition on what filter to use eventually.

- Duty Cycle: 54%

- range: 75 - 85 Mpc

- PRM M3 LL coil driver caused noise in 10-60 Hz range on Friday, may have been responsible for some loud glitches

- Also on Friday there were some strange lines in the strain spectrogram at around 10Hz

- loud glitches that cause brief, large drop in range that we saw in ER7 continue; the rate is improved

- link to full DQ shift

JeffreyK, Kiwamu, Darkhan

Overview

A DARM OLG TF model and its parts, sensing and actuation functions, are used for calculating the interferometer strain, h(t), and estimation of uncertainty in reported h(t).

On last Thursday we put together a DARM OLGTF Matlab model for ER8/O1 and compared it to a DARM OLGTF measurement taken on Aug 17, 2015. This model is mainly based on a similar model for ER7 (LHO alog 18769). Currently the model agrees with the measurement to only about +/-10% in magnitude and +/- 5 deg up to 200 Hz. So there's still work need to be done, probably changing parameter file needs some fine tuning of possibly following parameters: optical gain, CC pole frequency, ESD zeros and poles, ESD gain.

Details

Please, see a summary of things to be aware of when using this model (mostly listed differences from ER7 model):

• The following parameters at this point were fit by eye:
  • optical gain: 1.6*10^6
  • CC pole frequency: 338 Hz
  • ESD gain was adjusted by factor of 1.4
  • moved ESD driver pole to 138 Hz (not sure if this helped significantly)
• One major difference from ER7 model is that the new model generates all of the frequency dependent transfer functions in the form of LTI objects (zpk, ss, sos). This should make it more convenient to obtain frequency response of DARM parameters at a desired frequency vector.
• In ER7 time delays have been included only into overall OLGTF, but not into C, D and A. In ER8 model we explicitly included time delays at the places where they occur, i.e. SUS computation delay is included into discrete frequency response of SUS digital filters, total IOP downsampling TFs in C and A include their respective computation time delays, etc. E.g. below you can see the difference when comparing calculation of OLGTF in ER7 and ER8 models:
  • OLGTF from ER7 model is: G = C * D * A * time_delays
  • OLGTF from ER8 model is: G = C * D * A       (time delays were included into C, D and A)
• Since not all of the frequency dependent TFs that contribute to the DARM OLGTF are coming from discrete (computation) or analog/continuous (electronics, optics, mechanics) sources, but rather from mix of the two kinds, there is no a single LTI object for OLGTF (G), actuation (A) and sensing (C) functions. For user convenience this model includes inline functions that generate C, D, A and G transfer functions at a user requested frequency vector. E.g. if we want to obtain TFs in the range [10 .. 100] Hz with 1 Hz frequency resolution, following commands can be used:

[ol, par] = H1DARMmodel_ER8('par_file');

freq = 10 : 1 : 100;

G = par.G.getFreqResp_total(freq);

A = par.A.getFreqResp_total(freq); % total actuation function

% frequency responses of actuation stages can be obtained similarly

A_tst = par.A.getFreqResp_TST(freq);

% frequency responses of C with and without CC pole

C = par.C.getFreqResp_total(freq);

C_res = par.C.getFreqResp_noCavPole(freq);

• In ER7 for analog AA and AI filters both LHO and LLO sites used averaged frequency response of measurements taken at LLO. Recently Kiwamu and I processed AI filter measurements taken at LHO EY during calibration week before ER7 (LHO alog 18639), and produced a new zpk model of AA/AI filters based on these measurements (LHO alog 20769). Now we are using this new analog AA/AI model. One assumption that we are still making is that analog AA and AI filters have the same frequency response. To ensure that this assumption holds we will need to compare other AA and AI chassis measurements from pre ER7 (LHO alogs 18628, 18639) with the AA/AI model.

• In this DARM model the suspention TF is taken from a tagged suspension model that was recently created by Kiwamu and Sudarshan; this tag was also installed in calibrated Pcal RxPD and TxPD channels (LHO alog 20334).

• Another minor change is that parameter file for the measurement from 2015-08-17 uses OMC and SUS filter files that are copied into calibration SVN, this makes the scripts ready to run outside of control room.

We still need to take more DARM OLGTF and PCAL to DARM TF measurements and compare them to better estimate DARM model parameters.

The model was uploaded into calibration SVN (r1095):

CalSVN/aligocalibration/trunk/Runs/ER8/H1/Scripts/H1DARMOLGTFmodel_ER8.m

The parameter file associated with measurement taken on Aug 17 is in the same directory:

CalSVN/aligocalibration/trunk/Runs/ER8/H1/Scripts/DARMOLGTFs/H1DARMparams_1123894143.m

I believe that these scripts are in a reasonable shape to try it with LLO DARM parameters.

The fluid levels are essentially unchanged since the end of July.  The EndX is down <1/16" but I'll wait for more data to claim a trend from a leaky Accumulator.  No further HEPI Maintenance needed tomorrow.

BRS software crashed at the end of last week. I got a chance to head to EX and restart the code from the desktop in the rack room.

I kept the damper OFF for now to see whether or not it is rung up.

J. Kissel, K. Izumi, S. Karki, D. Tuyenbayev, R. Savage

I attach a picture of the whiteboard where we've sketched out our plan for the week. We've gone through T1500443, taken off items that we've already managed to capture before this week, and prioritized the remaining tasks accordingly.

Stay tuned for daily updates on progress.

J. Kissel, K. Izumi

At 16:02 UTC, we've taken the IFO down to begin calibration measurements.

On today's docket:
- Actuation function frequency dependence checks
    - UIM, PUM Coil Driver TFs
    - ESD LVLN Driver TFs
- Sensing function frequency dependence checks
    - OMC DCPD AA Chassis
    - OMC DCPD PreAmp (with single bounce IFO)

ALL TIMES IN UTC

Science Mode Checklist: (beginning of shift)

• Guardian:  NOMINAL_LOW_NOISE

• Inspiral Range: 62Mpc

• LVEA Sweep: N/A

• Ops Overview: Clean and Green (except for the beam diverter caveat)

• CDS Overview: Green except for Cal injections

• SDF Overview: All Diffs cleared except for  SUSPRM, OMC  and CALCS.

• SYS DIAG:  the usual BRS message

• Calibration Lines: Calibrations are running.

• ODC Master Observation Ready Bit: GREEN

• Observation Intent Bit: UNDISTURBED

• Ops Observatory Mode: Observing

Activity Log:

• 12:10 EY .3µ Dust Alarm Major

• 12:21 EY .3µ Dust Alarm Major

• 12:22 Set the Observation mode to ‘Environment’ while the earthquake settles down

• 12:26 Christina on site

• 12:26 Muted annoying EY dust monitor alarm

• 12:45  Took ISC_LOCK to down while Z-axis settles. Incessant OMC DCPD saturation Verbal Alarm after Lockloss and OMC still flashing. I called Evan and he instructed me to slide the ‘OFFSET’ slider in the OMC CONTROL Screen to the left a bit until the flashing stops. Guardian will touch this again when it’s time for locking. Verbal Alarm for this should be addressed as it was sounding excessively for an innocuous event according to Evan.

LOCK LOG:

• 11:42 IFO Locked at NLN. Range ~62Mpc.

• 11:59 Observation Intent Bit and Observatory Mode set

• 12:07 Lockloss.  There appears to be a mag 5 earthquake in the North Pacific off the coast of Russia

• 12:08  Begin locking sequence

  • DRMI - may take a while. mag 5 quake N Pacific/Russia

    • DRMI 1F locked after 15 minutes but came unlocked. I’m pretty sure it was the earthquake now

• 12:32 DRMI LOCKED

• 12:32 Attempt to proceed failed

• 12:57 Begin sequence (EQ calming) we’ll shoot for DRMI for starters.

  • DRMI Locked 1F in about 2 minutes

• 13:02 Lockloss. Never made it to 3F.

• 13:03 Begin sequence

  • DRMI Locked 1 min

• 13:19 Locked at NOMINAL_LOW_NOISE. 62Mpc

• 13:28 Set OIB and OOM to Undisturbed/Observing

Shift Summary:

• Most of the night was spent commissioning to resolve a problem with stability at “high” power.

• locking resumed at 11:42UTC and went well until an earthquake off the coast of Russia shook things up for about 1.5 hours.

• The wind stayed down all night and another good lock was achieved and hopefully will hold as I hand off to Jeff B. Only 1 ETMY saturation noted during this last lock, so far.

13:28UTC OIB and OOM set to Undisturbed/Observing

ALL TIMES IN UTC

Science Mode Checklist:

• Guardian:  NOMINAL_LOW_NOISE

• Inspiral Range: 62Mpc

• LVEA Sweep: N/A

• Ops Overview: Clean and Green (except for the beam diverter caveat)

• CDS Overview: Green except for Cal injections

• SDF Overview: All Diffs cleared except for  SUSPRM, OMC and CALCS.

• SYS DIAG:  the usual BRS message

• Calibration Lines: Calibrations are running.

• ODC Master Observation Ready Bit: GREEN

• Observation Intent Bit: UNDISTURBED

• Ops Observatory Mode: Observing

Activity Log:

• 11:42  got the “go ahead” to go to NOMINAL_LOW_NOISE. Range -60Mpc
• 11:59 Observation Intent Bit and Observatory Mode set
• 11:50 Evan has cleared most of the diffs in SDF Overview. PRM will stay red due to script workaround for current problem with LL OSEM signal and OMC will stay red because he wasn’t sure that the changes effected were meant to be permanent.

Sheila, Evan

We looked again at the situation with the 45 MHz REFL WFSs, which are used as sensors for the PR3 ASC loop. In the end, we didn't implement any changes to the sensors or the associated loops.

We were motivated by the following:

1. The current demod phases for these WFSs simply do not make sense; we expect that they should be similar (since the analog delays should be fairly well matched), but instead they are scattered by 100+ degrees.
2. The cHard and PR3 loops are strongly cross-coupled. We would like to be able to turn up the gain of cHard without impressing extra motion from other optics into DARM. [20523, 20497]
3. Any perturbation in the PR3 seems to couple into the SRC loops. We already know that the SRM loop is quite delicate, and we would like to get rid of this coupling if possible.

We tried the following:

• We changed the demod phases of the 45 MHz REFL WFSs, and then closed the PR3 loops.
  • We chose phases so that cHard pitch appears entirely in the Q phase (thereby leaving I dominated mostly by PR3 motion, hopefully). This was done previously, but loop retuning was not investigated in detail. Also, the phases of A3, A4, B3, and B4 seem to need an extra 180° phase shift in order to produce correctly phased signals (see screenshot).
  • We then found that only REFL45B gave a sensible error signal in response to PR3 motion (both pitch and yaw), so we closed the loops around B only. Additionally, the required digital gain went from 2 ct/ct (with the old phasing) to 40 ct/ct, perhaps indicating that the "old" PR3 configuration is actually dominated by cHard motion.
• This seemed to produce a constellation of bad things:
  • The sideband buildups (POP18 and AS90) were slightly suboptimal (i.e., fuzzy and not maximized).
  • The soft loops reduced the recycling gain (to 36 W/W or so) when they came on.
  • Switching the SRM yaw loop input matrix elements at 3 W seemed to make POP90 worse.
• We tried using new trans QPD offsets for the soft loops, but this led to the familiar angular instability when going to 20+ W.
• We also tried to find a new SRM yaw matrix element, but this didn't work either.
• We also turned off the dc oplev coupling on SR3, since we didn't want the optic position to be dragged away by the ground.
• In the end, we simply reverted all the changes we made.

After that, we couldn't get to full power because of an oscillation that showed up in dHard pitch when going to 20+ W. (We've seen this before, and it seems to be distinct from the angular instability mentioned above.) To get around this, we had to slightly beef up the resonant gain that gets turned on in dHard pitch when the power is increased.

Also, there were some small maintenance tasks that we did:

• Improved the filter hygiene of the DC centering loops (there were some integrators that didn't have ac gain of 1, some low-pass filters that didn't have dc gain of 1, some filters with ambiguous names, etc.)
• Added an optional ISC_LOCK guardian state called REDUCE_MODULATION_DEPTH, which implements the 3 dB modulation depth reduction that Stefan and I have carried out before.

ALL TIMES IN UTC

On my arrival, Evan, Sheila and Dan on site (of course Jim also). Not really any wind to speak of (~10mph). Minor earthquake activity in the last couple of hours after about 5 hours of quiet. Everyone gone except for Evan.

Science Mode Checklist: (since beginning of shift)

• Guardian:  actively running lock sequence while commissioners are troubleshooting

• Inspiral Range: N/A

• LVEA Sweep: N/A

• Ops Overview: In flux due to commissioning work

• CDS Overview: mostly green except for the typical OVF errors and the Calibration Line Excitation

• SDF Overview: Diffs showing on: SUSPRM, SUSSR3, LSC, ASC, OMC, ISCEX & ISCEY. Others are ODCX, ODCY and CALCS.

• SYS DIAG:  the usual BRS message

• Calibration Lines: It appears that Calibrations Lines are running.

• ODC Master Observation Ready Bit: RED

• Observation Intent Bit: Commissioning

• Ops Observatory Mode: Commissioning

Activity Log:

• 7:00 Evan and Sheila continuing work on ASC.

• 7:32 ETMX Dust Monitor giving Invalid Alarm

• 8:08 Refreshed the Operating mode FOMs

• 9:32  ETMX Dust Monitor giving Invalid Alarm

• 10:52 Still working on ASC issues

Using the calibrated DRMI channels created and described by Kiwamu in entry 18742, I grabbed data from the lock of August 3, 2015, starting at 04:20:00 UTC. The attached 4 page PDF shows spectra of the open loop and residual displacement noise for SRCL, MICH and PRCL. The 4th page shows the coherence of SRCL with the other 2 degrees of freedom.

The SRCL spectra has a curious shape: it comes down quickly with frequency to 10 Hz, then is fairly flat from 10 Hz to 50 Hz, then falls by a factor of 5 or so to the (presumed) shot noise level that is reached above 100 Hz. What is this noise shelf between 10 Hz and 80 Hz? That is exactly the region where the SRCL noise coupling to DARM is troublesome. Our usual approach is to send a SRCL correction path to DARM to reduce the coupling, but this spectrum shows that there should also be some gain to be had by reducing this noise shelf.

The last page of the PDF shows the coherence between SRCL and MICH & PRCL, and it indicates that the SRCL noise shelf could be coupling from PRCL noise -- the coherence is fairly high in this band, though not unity. This suggests that the DRMI signals could use some of the demodulator phase and input matrix tuning that Rana has recently done on L1, reported in LLO log entry 19540.

To complete this log entry, it would be useful if someone at LHO could add the open loop transfer functions for each loop (models), and other pertinent info such as DC photocurrents for these detectors and the input matrix coefficients.

We observed broadband coherence of OMC_DC_SUM with ASC_AS_C_LF_SUM and ASC_A_RF36_PIT. We made some numbers and plots, using the 64kHz version of the channels.

First the measurements we made on OCXO oscillator:
- ASC_AS_C sees a RIN of about 5e-7/rtHz above 100Hz (either from H1:ASC-AS_C_SUM_OUT_DQ or from H1:IOP-ASC0_MADC6_TP_CH11). The same is true for its segment 1.
- The calculated shot noise RIN at 20mA (quantum efficiency 0.87) detected is 4.0e-9/rtHz.
- The 4.0e-9/rtHz agrees with DCPD_NULL_OUT_DQ's prediction (8.0e-8 mA/rtHz/20mA).
- DCPD_SUM_OUT_DQ sees a slightly elevated RIN of 4.6e-9/rtHz (9.2e-8 mA/rtHz/20mA).

- The RIN in DCPDA (H1:IOP-LSC0_MADC0_TP_CH12, corrected for the whitening) is about 5.9e-8 mA/rtHz, or RIN = 5.9e-9/rtHz at 20mA/2diodes (~15pm DARM offset)...
- ...or about 3.3e-8 mA/rtHz or 1.2e-8/rtHz at 5.7mA/2diodes (~8pm DARM offset).

- ASC-AS_C_SEG1 (H1:IOP-ASC0_MADC6_TP_CH11) and OMC-DCPD_A (H1:IOP-LSC0_MADC0_TP_CH12) shows a coherence of 0.053 at 20mA, suggesting a white noise floor a factor of 0.23 below shot noise.
- At 5.7mA the same coherence is about 0.13, i.e. the white noise floor is a factor of 0.39 below shot noise.
- These two measurements are in plot 1.

- Taking the last two statements together, we predict a coherent noise of
  - 5.9e-8 mA/rtHz *0.23 = 1.4e-8 mA/rtHz at 20mA/2diodes (~15pm DARM offset)  (RIN of coherent noise = 1.4e-9/rtHz) - The pure shot noise part is thus 5.7e-8 mA/rtHz
  - 3.3e-8 mA/rtHz *0.39 = 1.3e-8 mA/rtHz at 5.7mA/2diodes (~8pm DARM offset)  (RIN of coherent noise = 4.5e-9/rtHz) - The pure shot noise part is thus 3.0e-8 mA/rtHz.

- AS_C calibration:
 - 200V/W (see alog 15431)
 - quantum efficiency 0.8 (see alog 15431)
 - 0.25% of the HAM 6 light (see alog 15431)
 - We have 39200cts in the AS_C_SUM. Thus we have
   - 39200cts / (1638.4cts/V) * 10^(-36/40) (whitening) / (200V/W) = 1.89mW and AS_C. (shot noi
   - 1.89mW/0.025 = 76mW entering HAM6. I.e. we have slightly more sideband power than carrier power (Carrier: 27mW in OMC transmission).
   - Shot noise level on AS_C_SUM is at 2.0e-8 mA/rtHz, corresponding to a RIN of 1.6e-8/rtHz. I.e. the coherent noise seen at 5e-7/rtHz is high above the shot noise. Dark noise TBD.
   - The light entering HAM 6 has a white noise of 5e-7/rtHz*76mW = 3.8e-5 mW/rtHz 
    

Bottom line:
 -We have ~1.4e-8mA/rtHz, or 1.9e-8mW/rtHz of coherent white noise on each DCPD.
 -It corresponds to 3.8e-5mW/rtHz before the OMC, i.e. the the OMC seems to attenuate this component by 2000.
 -This noise stays at the same level (in mW/rtHz) for different DCPD offsets.


Next, we switched back to the IFR for testing. plot 2 shows the same coherences (all at 5.7mA / 8pm DARM offset), but on the IFR. Interestingly now AS_C and AS_A_RF36 start seeing different noise below 2kHz. We convinced our selfs that the higher excess noise seen in AS_A_RF36 is indeed oscillator phase noise from the IFR - so that is clearly out of the picture once of the OCXO. (Evan will shortly log the oscillator phase noise predictions.)


64k Channel list:
H1:IOP-LSC0_MADC0_TP_CH12:     OMC-DCPD_A  (used in plot)
H1:IOP-LSC0_MADC0_TP_CH13:     OMC-DCPD_B
H1:IOP-LSC0_MADC1_TP_CH20:     REFLAIR_A_RF9_Q
H1:IOP-LSC0_MADC1_TP_CH21:     REFLAIR_A_RF9_I
H1:IOP-LSC0_MADC1_TP_CH22:     REFLAIR_A_RF45_Q
H1:IOP-LSC0_MADC1_TP_CH23:     REFLAIR_A_RF45_I
H1:IOP-LSC0_MADC1_TP_CH28:     REFL_A_RF9_Q
H1:IOP-LSC0_MADC1_TP_CH29:     REFL_A_RF9_I
H1:IOP-LSC0_MADC1_TP_CH30:     REFL_A_RF45_Q
H1:IOP-LSC0_MADC1_TP_CH31:     REFL_A_RF45_I


H1:IOP-ASC0_MADC4_TP_CH8:      ASC-AS_A_RF36_I1
H1:IOP-ASC0_MADC4_TP_CH9:      ASC-AS_A_RF36_Q1
H1:IOP-ASC0_MADC4_TP_CH10:     ASC-AS_A_RF36_I2
H1:IOP-ASC0_MADC4_TP_CH11:     ASC-AS_A_RF36_Q2
H1:IOP-ASC0_MADC4_TP_CH12:     ASC-AS_A_RF36_I3
H1:IOP-ASC0_MADC4_TP_CH13:     ASC-AS_A_RF36_Q3   (used in plot)
H1:IOP-ASC0_MADC4_TP_CH14:     ASC-AS_A_RF36_I4
H1:IOP-ASC0_MADC4_TP_CH15:     ASC-AS_A_RF36_Q4

H1:IOP-ASC0_MADC6_TP_CH11:     ASC-AS_C_SEG1  (used in plot)
H1:IOP-ASC0_MADC6_TP_CH10:     ASC-AS_C_SEG2
H1:IOP-ASC0_MADC6_TP_CH9:      ASC-AS_C_SEG3
H1:IOP-ASC0_MADC6_TP_CH8:      ASC-AS_C_SEG4