[Anchal, Yuta, Paco]

Late elog (from yesterday) -- We locked FPMI, YAUX, and turned on calibration lines from gpstimes = 1355539386 to 1355539594 (lost lock because IMC unlocked )

We followed the steps in this elog and handed off from an electronic FPMI (POX, POY) to the RF one (REFL55 and AS55). We will continue this work today and try to finish a restore FPMI script to make it more robust.

[Anchal, Paco, Yuta]

FPMI locked with BHD readout!!!

Paco and I figured the repeatable recipe for locking FPMI today. The settings are saved as snapshot file. In short, we first lock fake FPMI using POX+POY and POX-POY and then locking MICH to REFL55_Q. We make sure there are no offsets in AS55Q or REFL55Q. Then we handoff CARM and DARM loops to 0.496*REFL55_I and 2.617*AS55_Q by changing gains on A and B paths simultaneously with tramp time of 5s. WE have pushed new measurements of CARM, DARM and MICH loop OLTFs to measurement repo.

We turned on 5 oscillators all sending calibration lines to ITMY at different frequencies to calibrate DARM readout. WE took this data for about 90 minutes and then decided to try locking FPMI with BHDC DIFF.

A simple handoff to 0.68*BHDC_DIFF at error point for DARM loop worked. The OLTF for DARM loop remained the same.

I need to run now, so more detailed elog will come later.

On another news, this was last day of Tega, a warm farewell to him.

[Yuta, Paco]

We tried restoring the FPMI BHD readout from yesterday but failed. Below is a summary of what we did.

Steps

1. Align arms, MICH and LO (using ITMY single bounce).
2. Lock both CARM and DARM with POX/POY to restore the "electronic" FPMI.
3. Lock MICH with REFL55_Q.
4. Handoff DARM to AS55_Q and CARM to REFL55_I.
5. Lock LO_PHASE using BH55_Q
6. Balance BHD_DCPD to remove offset in BHD_DIFF
7. Measure the C1:LSC-BHDC_DIFF_OUT / C1:LSC-AS55_Q_ERR ratio to get the DARM content in BHD DIFF.
8. Attempt DARM control handoff from AS55_Q to BHDC_DIFF  --- this step didn't work today despite our several attempts.

We found LO fringe alignment to be really important, as sometimes we would try to calibrate the DARM content of BHD DIFF and found almost no coherence between AS55_Q and BHD_DIFF, but after realigning the coherence was increased and the lock was better. Another difference with respect to yesterday was the sign flip implied by the measured ratio from step 7.

Calibrated FPMI noise spectra

In anticipation to restoring FPMI BHD, we took a calibrated FPMI noise spectra (error and control point). The saved diaggui template that produces Attachment #1 is on /cvs/cds/rtcds/caltech/c1/Git/40m/measurements/LSC/FPMI/FPMI_calibrated_noise.xml Our calibration was based on sensing matrix measuring the DARM content on AS55_Q which was 1 / (2.617 * 3.64e11 counts/m) =  1.0497e-12 m/count, and the (balanced) ETM plant = 10.91e-9 / f^2 m/counts.

Next steps

Sadly we couldn't take a FPMI BHD calibrated noise spectra, but things to look into next time are

• Take TFs for FPMI CARM, DARM and MICH loops. We skipped this today, perhaps wrongfully so.
• Measure the FPMI sensing matrix to check demod phases and optical gains (related to the above).

[Paco, Yuta]

We recovered FPMI BHD, and sensitivity was estimated. High frequency sensitivity is improved by an order of magnitude compared with AS55 FPMI.
We also estimated the contribution from LO phase noise, and found that LO phase noise is not limiting the sensitivity.

Locking sequence:

1. Lock electronic FPMI

DARM:
 - 0.5 * POX11_I - 0.5 * POY11_I
 - DARM filter module, FM4,5 for acquisition, FM1,2,3,6,8 triggered, C1:LSC-DARM_GAIN = 0.015 (gain lowered from BHD FPMI in December (was 0.02) to have more gain margin)
 - Actuation on 0.5 * ETMX - 0.5 * ETMY
 - UGF ~ 150 Hz

CARM:
 - 0.5 * POX11_I + 0.5 * POY11_I
 - CARM filter module, FM4,5 for acquisition, FM1,2,3,6,8 triggered, C1:LSC-CARM_GAIN = 0.012
 - Actuation on -0.734 * MC2

2. Lock MICH

MICH:
 - 1.1 * REFL55_Q
 - MICH filter module, FM4,5,8 for acquisition, FM2,3,6 triggered, C1:LSC-MICH_GAIN = +10
 - Actuation on 0.5 * BS
 - UGF ~35 Hz (Attachment #1)

3. Hand over to real DARM/CARM

DARM:
 - 2.617 * AS55_Q

CARM:
 - 0.496 * REFL55_I
 - UGF ~200 Hz (Attachment #2)

4. Lock LO_PHASE

LO_PHASE:
 - 1 * BH55_Q (demod phase: -110 deg; this was chosen by hand to maximize fringe in BH55_Q when FPMI is locked. This seemed to make more robust LO_PHASE lock, compared with December)
 - FM5,8, C1:HPC-LO_PHASE_GAIN=-1
 - Acuation on 1 * LO1
 - UGF ~110 Hz (Attachment #3)

5. Hand over to BHD_DIFF

DARM:
 - -1.91 * BHD_DIFF (ratio between AS55_Q to BHD_DIFF was measured with a DARM line at 575.125 Hz, which was measured to be -0.455; BHD_DIFF was zeroed by balancing A and B before the measurement)
 - UGF ~150Hz (Attachment #4)

Measured sensing matrix:

/opt/rtcds/caltech/c1/Git/40m/scripts/CAL/SensingMatrix/ReadSensMat.ipynb

Sensing matrix with the following demodulation phases (counts/counts)
{'AS55': -168.5, 'REFL55': 92.32, 'BH55': -110.0}
Sensors       DARM @307.88 Hz           CARM @309.21 Hz            MICH @311.1 Hz        LO1 @315.17 Hz           
AS55_I       (-0.35+/-1.44)e-02        (+3.23+/-1.09)e-02        (-0.18+/-9.84)e-03    (+0.02+/-1.33)e-03    
AS55_Q       (-0.45+/-3.48)e-02        (-0.19+/-1.23)e-02        (+0.05+/-1.43)e-03    (-0.02+/-2.03)e-04    
REFL55_I     (+0.05+/-1.31)e-01        (+4.51+/-0.07)e-01        (-0.03+/-3.44)e-02    (+0.11+/-1.01)e-03    
REFL55_Q     (-0.39+/-4.74)e-04        (-1.36+/-0.50)e-03        (+0.16+/-2.80)e-04    (+0.10+/-4.92)e-05    
BH55_I       (-1.90+/-5.00)e-03        (+0.80+/-8.82)e-03        (-0.50+/-2.29)e-03    (-4.61+/-9.52)e-04    
BH55_Q       (-0.31+/-4.86)e-02        (-3.13+/-3.04)e-02        (-0.06+/-1.07)e-02    (-1.42+/-2.11)e-03    
BHDC_DIFF    (-5.56+/-0.21)e-02        (+0.10+/-1.64)e-02        (+0.10+/-1.40)e-03    (+0.77+/-2.27)e-04    
BHDC_SUM     (+1.75+/-3.90)e-03        (-1.22+/-3.22)e-03        (-0.35+/-1.52)e-03    (-0.36+/-6.42)e-04

Sensing matrix with the following demodulation phases (counts/m)
{'AS55': -168.5, 'REFL55': 92.32, 'BH55': -110.0}
Sensors       DARM @307.88 Hz           CARM @309.21 Hz           MICH @311.1 Hz        LO1 @315.17 Hz           
AS55_I       (-0.30+/-1.25)e+11        (+2.18+/-0.73)e+11       (-0.07+/-3.59)e+10    (+0.08+/-5.02)e+09    
AS55_Q       (-0.39+/-3.03)e+11        (-1.27+/-8.32)e+10       (+0.20+/-5.23)e+09    (-0.06+/-7.66)e+08    
REFL55_I     (+0.04+/-1.14)e+12        (+3.05+/-0.05)e+12       (-0.01+/-1.26)e+11    (+0.42+/-3.82)e+09    
REFL55_Q     (-0.34+/-4.12)e+09        (-9.20+/-3.37)e+09       (+0.06+/-1.02)e+09    (+0.04+/-1.86)e+08    
BH55_I       (-1.65+/-4.34)e+10        (+0.54+/-5.95)e+10       (-1.83+/-8.36)e+09    (-1.74+/-3.59)e+09    
BH55_Q       (-0.27+/-4.23)e+11        (-2.11+/-2.05)e+11       (-0.21+/-3.91)e+10    (-5.36+/-7.98)e+09    
BHDC_DIFF    (-4.83+/-0.18)e+11        (+0.07+/-1.11)e+11       (+0.35+/-5.09)e+09    (+2.90+/-8.56)e+08    
BHDC_SUM     (+1.52+/-3.39)e+10        (-0.82+/-2.17)e+10       (-1.29+/-5.56)e+09    (-0.14+/-2.42)e+09

NOTE that some of sensing matrix element (e.g. DARM to AS55_Q) is wrong, because of ill defined sign in C1:CAL-SENSMAT_XXXX_XXXX_AMPMON channels.

Locked GPS times:
 - 1357511737 to 1357513050
 - 1357513448 to 1357518188 (intentionally unlocked)

Sensitivity estimate:
 - See Attachment #5 and #6 (high frequency zoomed), dashed traces with darker colors are of AS55_Q FPMI from 40m/17369.
 - DARM_IN1 was calibrated using DARM content in BHD_DIFF, with 1 / (1.91 * 4.83e11 counts/m) = 1.086e-12 m/counts (which should be similar to DARM_IN1 calibration for AS55_Q, because we are balancing the error signals going to DARM_IN1, and it is as expected; see 40m/17369).
 - DARM_OUT calibration is the same as 40m/17369; ETM plant = 10.91e-9 / f^2 m/counts.
 - LO phase noise was estimated using BH55_Q, with the collowing calibration factor (BH55_Q calibrated into LO1 motion, into BHD_DIFF, and then into DARM).

1/5.36e9*2.9e8/4.83e11 = 1.15e-13 m/counts

 - Seismic noise was estimated using C1:IOO-MC_F_DQ, with the same calibration factor found in 40m/16975.
 - Dark noise was estimated using DARM_IN1 when the PSL shutter is closed.

Discussion:
 - Sensitivity below ~10 Hz is probably limited by seismic noise
 - Noise above 1 kHz might be limited by dark noise of BHD_DIFF, but not below 1 kHz. For AS55_Q FPMI, sensitivity above ~300 Hz was limited by dark noise.
 - LO phase noise is not limiting the sensitivity, from the estimated noise using BH55_Q.
 - Both BH55_Q and BHD_DIFF have funny structure like forest above ~100 Hz. This might be from suspensions in the AS path and LO path to BHD. It could also be that calibration lines for measuring sensing matrix were too much (BHD FPMI sensitivity was measured with calibration lines around ~310 Hz on).

Next:
 - Update the c1cal model to put correct signs to C1:CAL-SENSMAT_XXXX_XXXX_AMPMON channels.
 - Measure BHD FPMI sensitivity with calibration lines off.
 - Find better LO phase to improve the sensitivity.
 - Lock LO phase with RF+audio and RF44 and compare the sensitivity.
 - Move on to PRFPMI BHD.

Here's the same sensitivity plot from yesterday (40m/17392), but with higher frequency resolution, upto 6.9 kHz, using GPS times from yesterday.
Now curves from FPMI with AS55_Q are also from yesterday, just before switching to BHD, so it will be more direct comparison

[Paco, Yuta]

Gains in DARM are corrected to make it more calibration friendly.

DARM error signals
 - 0.19 * POX11_I - 0.19 * POY11_I
 - 1 * AS55_Q
 - -0.455 * BHD_DIFF (needs to be checked if LO phase is different)

DARM gain:
 - C1:LSC-DARM_GAIN = 0.04 (it was 0.015 to have UGF of ~150 Hz)

Online calibration:
 - FM2 for C1:CAL-DARM_CINV was turned on, which is a calibration for AS55_Q in FPMI; 1 / (3.64e11 counts/m) = 2.747e-12 m/counts (see sensing matrix below; consistent with 40m/17369).
 - FM2 for C1:CAL-DARM_A was updated to 10.91e-9 (40m/16977).
 - C1:CAL-DARM_W_OUT will be our calibrated FPMI displacement in meters. This is correct with BHD_DIFF locking, if the BHD_DIFF is balanced with AS55_Q before DARM_IN1.

FPMI sensitivity:
 - Attached plot shows the sensitivity of FPMI with AS55_Q and BHD_DIFF, plotted together with their dark noise.
 - The sensisitivty was measured with calibration lines off and notches off, which removed the forest of lines we saw on Jan 11 (40m/17392).

FPMI sensing matrix:
 - Attached is a screenshot of uncalibrated sensing matrix MEDM screen. Audio demodulation phase for DARM was tuned to have stable sign.
 - The following is calibrated sensing matrix measured today with FPMI locked with AS55_Q. BH55 and BHD_DIFF have large uncertainties because LO_PHASE locking is not stable.

Sensing matrix with the following demodulation phases (counts/m)
{'AS55': -168.5, 'REFL55': 92.32, 'BH55': -110.0}
Sensors       DARM @307.88 Hz           CARM @309.21 Hz           MICH @311.1 Hz           LO1 @315.17 Hz           
AS55_I       (-3.28+/-0.90)e+11 [90]    (-0.05+/-2.53)e+11 [0]    (+0.47+/-2.14)e+10 [0]    (-0.06+/-1.76)e+09 [0]    
AS55_Q       (-3.64+/-0.08)e+11 [90]    (-0.09+/-8.30)e+10 [0]    (-0.28+/-2.24)e+09 [0]    (+0.12+/-1.16)e+08 [0]    
REFL55_I       (+0.07+/-1.24)e+12 [90]    (+3.32+/-0.06)e+12 [0]    (-0.01+/-1.39)e+11 [0]    (+0.00+/-1.12)e+09 [0]    
REFL55_Q       (-0.98+/-2.46)e+09 [90]    (-4.68+/-2.04)e+09 [0]    (+0.08+/-1.00)e+09 [0]    (+1.73+/-5.69)e+07 [0]    
BH55_I       (-6.84+/-2.47)e+11 [90]    (+0.43+/-2.32)e+11 [0]    (-0.33+/-6.21)e+10 [0]    (-2.51+/-8.09)e+09 [0]    
BH55_Q       (+5.68+/-1.57)e+11 [90]    (-0.17+/-2.52)e+11 [0]    (-0.46+/-4.39)e+10 [0]    (+0.73+/-5.01)e+09 [0]    
BHDC_DIFF       (-2.48+/-3.47)e+11 [90]    (-0.09+/-1.99)e+11 [0]    (+1.56+/-4.11)e+10 [0]    (-0.49+/-6.78)e+09 [0]    
BHDC_SUM       (-2.12+/-1.84)e+10 [90]    (+0.35+/-1.44)e+10 [0]    (-1.30+/-4.18)e+09 [0]    (-0.03+/-8.17)e+08 [0]    

Current status:
 - After locking FPMI BHD to get the FPMI sensitivity today, we are struggling to re-lock again. LO_PHASE locking is glitchy today for some reason. To be investigated.
 

[Paco, Yuta]

After several hours of unattended IFO, we realigned the IFO and somehow BH55_Q error signal looked better, LO_PHASE locking was more robust, and we could lock FPMI BHD.

Sensing matrix:
 - Attached #1 is the sensing matrix with FPMI BHD locked, with LO_PHASE locked with BH55_Q using AS4, and below is the calibrated one.

Sensing matrix with the following demodulation phases (counts/m)
{'AS55': -168.5, 'REFL55': 92.32, 'BH55': -110.0}
Sensors       DARM @307.88 Hz           CARM @309.21 Hz           MICH @311.1 Hz           LO1 @315.17 Hz           
AS55_I       (+0.43+/-2.22)e+11 [90]    (+5.26+/-1.26)e+11 [0]    (-0.15+/-5.88)e+10 [0]    (+0.05+/-1.94)e+09 [0]    
AS55_Q       (-3.73+/-0.19)e+11 [90]    (-0.09+/-1.06)e+11 [0]    (+0.21+/-6.82)e+09 [0]    (-0.24+/-2.41)e+08 [0]    
REFL55_I       (+0.08+/-1.17)e+12 [90]    (+3.14+/-0.07)e+12 [0]    (-0.01+/-1.31)e+11 [0]    (+0.07+/-1.03)e+09 [0]    
REFL55_Q       (+0.51+/-1.09)e+10 [90]    (+1.80+/-2.35)e+10 [0]    (+0.01+/-1.44)e+09 [0]    (-0.79+/-5.41)e+07 [0]    
BH55_I       (+1.20+/-0.34)e+11 [90]    (+0.26+/-1.07)e+11 [0]    (-0.04+/-1.33)e+10 [0]    (-1.07+/-1.82)e+09 [0]    
BH55_Q       (+1.12+/-1.52)e+11 [90]    (-3.40+/-1.98)e+11 [0]    (-0.01+/-4.16)e+10 [0]    (-5.55+/-1.66)e+09 [0]    
BHDC_DIFF       (+6.95+/-0.25)e+11 [90]    (+0.01+/-1.60)e+11 [0]    (-0.70+/-4.49)e+09 [0]    (+4.24+/-4.14)e+08 [0]    
BHDC_SUM       (+7.06+/-2.64)e+10 [90]    (-0.32+/-3.24)e+10 [0]    (+0.05+/-4.26)e+09 [0]    (+1.30+/-6.33)e+08 [0]    

BH55_Q:
 - We are not sure why BH55_Q error signal got better. Peak to peak amptidue of BH55_Q when LO_PHASE is not locked is at around 800 (even if LO_PHASE locking cannot be stably locked), but when we couldn't lock LO_PHASE stably, it was noisier. This suggests that BHD alignment is not bad.
 - Attachment #2 shows the spectrum of BHDC_DIFF, BH55_Q (measured at LO_PHASE_IN1) and AS55_Q when FPMI is locked with AS55_Q, and LO_PHASE is locked with BH55_Q. Dashed darker curves are when we could not lock LO_PHASE stably. You can see broad noise in BH55_Q at around 60 Hz and its harmonics when it is noisy, but they are not present when LO_PHASE can be locked stably. Also, AS55_Q stays the same, which suggests that the cause is not in FPMI to AS55, but in BHD path to BH55.

Sensitivity comparison with different LO_PHASE locking actuator:
  - We compared FPMI sensitivity with LO_PHASE locked with LO1 (red) vs with AS4 (orange). Didn't change, as expected (Attachment #3).

Next:
 - Investigate what is causing noisy BH55. Is it FPMI alignment, BHD alignment, suspensions in LO/AS paths, or electronics?
 - Try locking LO_PHASE with an offset to BH55_Q to see if BHD_DIFF sensitivity to DARM changes, and to see if we can reduce BHD_DIFF dark noise contribution to FPMI sensitivity
 - Try BH55+audio and BH44 to lock LO_PHASE.
 - PRMI and PRFPMI

@OMC Lab
EP30-2 Epoxy bonding of V beam dumps for LSC PDs.

- Supplied 1"x0.5" glass pieces from the stock in the OMC lab.
- The black glass pieces were cleaned by IPA / Aceton / Aceton+Cotton Qtip scrub / First Contact
- 3 beam dumps are built. They require ~24 hrs to get cured.

=> Handed to Yuta on Jan 27, 2023

The arms in the 40m laboratory have now been sectioned off. Each arm has been divided up into 15 sections. Along the Y arm, the section are labelled "Section Y1 - Section Y15". For the X arm, they are labelled "Section X1- Section X15". Anything changed or moved will now be updated into the elog with their appropriate section.

Below is an example of Section X6.

The floor cable cover has been changed out for a new one. This is in Section X11.

During Wednesday’s lab clean up, we made a ton of progress in organization. Our main focus was to tackle CDS debris from the ongoing upgrade. We proceeded with the following tasks.

• Loop the OneStop Cables and mark ‘good’ or ‘bad’.
• Clean materials from the PD testing table.
• Removed the SuperMicro boxes from the lab
• Vacuum area organization.
• Remove old plastic containers from the laboratory.
• Relocate Koji’s electronics underneath Y-Arm
• Arrange cabling to the TestStand and create clearance to the Machine Shop/Laboratory exit.

Attachment #2 shows that all the CDS equipment has been relocated behind Section X3 of the X-Arm.

I have moved the following electronics / components to "Section Y10 beneath the tube"

• IQ Demod Spares D0902745 (Components)
• Sat Box / HAM-A 40m parts D08276/D110117
• 16bit DAC AI Rear PCB D070101-v3
• D1900163 HV COIL DRIVER
• Ribbon Cables for Chassis (Cardboard box)
• Chassis DC Breaker Switches (Cardboard box)
• Triplett HDMI displays (x3) / Good for portable CCD monitors / PC monitors. Battery powered!
• ISC Whitening BI Config Boards D1001631/D1900166
• AA/AI Untested D070081
• WFS Interface / Soft Start D1101865/D1101816
• Internal Wiring Kit Cable Spools
• ISC Whitening / Interface D1001530 / D1002054
• aLIGO WFS Head D1101614
• Internal Wiring Kit (Large Plastic Box)
• Front/Rear Panels (Large Plastic Box)
• HV Coil Driver Test Kit / Spare PA95s (Large Plastic Box)

The new tool box has came in! I have spent serious time organizing these tools and making it look pretty, so please take care of it! A few things I would like to note.

• The tool box has a power strip, so this is now where we will be charging the power tools. There is also a selected cabinet for the fully charged batteries, bits, and the power tools themselves. 
• The cart next to the tool box had to turned 90 degrees in order to fit the tool box in. While moving this, I noticed this cart is piled with random stuff, let’s tackle this on Wednesdays clean up.
• The tools from this tool box are specifically assigned to the VERTEX area (and the X-End until we get another toolbox.) Please return all the tools in their right tool box and cabinet after usage. 
• The heavier duty equipment such as pipe wrenches, hammers, and power tools will remained stored here in the bottom cabinets. 

Hope you all like it!

The NPRO from ATF has been installed on the POY table.

I have been making measurements to characterize the beam profile of this laser. I am using an AR coated laser window as a beam sampler at 45deg and the razor blade technique to measure the beam size along z. Details of the procedure along with analysis and results from this will follow.

 __Epics_Channel_Name______   __OLD_____    ___New___
 C1:SUS-MC1_PIT_COMM          4.490900        3.246900 
 C1:SUS-MC1_YAW_COMM          0.105500	      -0.912500
 C1:SUS-MC2_PIT_COMM          3.809700	      3.658600 
 C1:SUS-MC2_YAW_COMM          -1.837100	      -1.217100
 C1:SUS-MC3_PIT_COMM          -0.614200	      -0.812200
 C1:SUS-MC3_YAW_COMM          -3.696800	      -3.303800

Yoichi, Peter

While continuing our efforts to lock, we noticed the procedure failed at a point it had gotten past last night:  turning on the bounce/roll filters in MICH, PRC, and SRC.  We checked the MICH transfer function and noticed that the unity gain point was ~10 Hz, well below the bounce modes.   We tried increasing the gain but found saturation, and Rob suggested that there could be misalignment on the AP table, which Steve worked on today.  We went out and found two of the PDs (ASDD133 and AS166) to be badly misaligned probably due to a bumped optic upstream.  We re-aligned.