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ID Date Author Type Categoryup Subject Text Attachments
  17142   Thu Sep 15 21:12:53 2022 PacoUpdateBHDLO phase "dc" controlLocked the LO phase with a MICH offset=+91.
The LO is midfringe (locked using the A-B
zero crossing), so it's far from being
 lophase_oltf.pdflophase_noise_spectra.pdf 
  17146   Tue Sep 20 15:40:07 2022 yehonathanUpdateBHDTrying doing AC lockWe resume the LO phase locking work. MICH
was locked with an offset of 80 cts. LO and
AS beams were aligned to maximize the BHD
 Screenshot_2022-09-20_15-38-44.png 
  17150   Wed Sep 21 17:01:59 2022 PacoUpdateBHDBH55 RFPD installed - part I[Radhika, Paco]

Optical path setup

We
realized the DCPD - B beam path was already
 IMG_3760.jpegIMG_3764.jpeg 
  17152   Thu Sep 22 19:51:58 2022 AnchalUpdateBHDBH55 LSC Model Updates - part III updated follwoing in teh rtcds models
and medm screens:


c1lsc

Added
  
  17155   Fri Sep 23 14:10:19 2022 RadhikaUpdateBHDBH55 RFPD installed - part I[Radhika, Paco, Anchal]

I placed a lens in the B-beam
path to focus the beam spot onto the RFPD
 IMG_3766.jpegIMG_3770.jpegIMG_3773.jpeg 
  17156   Fri Sep 23 18:31:46 2022 ranaUpdateBHDBH55 RFPD installed - part IA design flaw in these initial LIGO RFPDs
is that the SMA connector is not strain releieved
by mounting to the case. Since it is only
  
  17157   Fri Sep 23 19:04:12 2022 AnchalUpdateBHDBH55 LSC Model Updates - part IIIBH55

I further
updated LSC model today with following changes:


BH55 whitening switch binary
  
  17159   Mon Sep 26 11:39:37 2022 PacoUpdateBHDBH55 RFPD installed - part II[Paco, Anchal]

We followed rana's suggestion
for stress relief on the SMA joint in the
 PXL_20220926_175010061.MOTION.jpgBH55_Transimpedance_Measurement.pdf 
  17160   Tue Sep 27 10:50:11 2022 PacoUpdateBHDcalibrated LO phase noiseLocked LO phase to ITMX single bounce beam
at the AS port, using the DCPD (A-B) error
point and actuating on LO1 POS. For this
 lo_phase_asd.pdf 
  17161   Wed Sep 28 16:37:26 2022 PacoUpdateBHDcalibrated LO phase noise; update[yuta, paco]

Update; the high frequency ( >
100 Hz) drop is of course not real and comes
 lo_phase_asd.pdf 
  17163   Wed Sep 28 21:54:08 2022 PacoUpdateBHDcalibrated LO phase noise; updateRepeated the LO phase noise measurement,
this time with the LO - ITMY single
bounce, and a couple of fixes Koji
 dcpd_phase_asd.pdflo_phase_asd.pdf 
  17165   Thu Sep 29 18:01:14 2022 AnchalUpdateBHDBH55 LSC Model Updates - part IVMore model changes

c1lsc:


BH55_I and BH55_Q are now
being read at ADC_0_14 and ADC_0_15. The
  
  17167   Fri Sep 30 20:18:55 2022 PacoUpdateBHDLO phase noise with different actuation points[Paco, Koji]

We took lo phase noise spectra
actuating on the for different optics-- LO1,
 BHDC_asd_actuation_point.png 
  17170   Mon Oct 3 13:11:22 2022 YehonathanUpdateBHDSome comparison of LO phase lock schemesI pushed a notebook and a Finesse model
for comparing different LO phase locking
schemes. Notebook is on https://git.ligo.org/40m/bhd/-/blob/master/controls/compare_LO_phase_locking_schemes.ipynb,
 MICH_sens_vs_LO_phase.pdfLO_phase_sens_vs_LO_phase_RF.pdfLO_phase_sens_vs_LO_phase_double_audio.pdf 
  17171   Mon Oct 3 15:19:05 2022 PacoUpdateBHDLO phase noise and control after violin mode filters[Anchal, Paco]

We started the day by taking a
spectrum of C1:HPC-LO_PHASE_IN1,
 filters_c1sus_lo1_lsc.pngBHDC_asd_act.pngboosted_lo_phase_control.png 
  17174   Thu Oct 6 11:12:14 2022 AnchalUpdateBHDBH55 RFPD installation complete[Yuta, Paco, Anchal]

BH55 RFPD installation was still
not complete until yesterday because of a
  
  17176   Thu Oct 6 18:50:57 2022 AnchalSummaryBHDBH55 meas diff angle estimation and LO phase lock attempts[Yuta, Paco, Anchal]

BH55 meas diff

We
estimated meas diff angle for BH55 today
  
  17191   Fri Oct 14 17:04:28 2022 RadhikaUpdateBHDBH55 Q abnormality + fix[Yuta, Anchal, Radhika]

Yesterday we attempted to lock
MICH and BHD using the BH55_Q_ERR signal.
 IMG_3805.jpegIMG_3807.jpegBH55_IQDemodMeasuredDiff_1349737773.png 
  17195   Mon Oct 17 20:04:16 2022 AnchalUpdateBHDBH55 RF output amplified[Radhika, Anchal]

We have added an RF amplifier to
the output of BH55. See the MICH signal on
 BH55_RF_Amp_Working.pngrn_image_picker_lib_temp_1b072d08-3780-4b1d-9325-5795ed099d3d.jpgrn_image_picker_lib_temp_9d7ed3c0-7ff0-4ff7-9349-0211be397dc5.jpgrn_image_picker_lib_temp_05da14e1-eae0-4a84-8761-1c42b122cb1b.jpg 
  17196   Mon Oct 17 22:27:25 2022 ranaUpdateBHDBH55 RF output amplified1) please remember to follow the loading
and power up instructions to avoid destroying
our low noise RF amplifiers. Its not as easy
  
  17200   Wed Oct 19 11:09:20 2022 RadhikaUpdateBHDBH55 RF output amplified[Anchal, Radhika]

We selected a 102K (1 nF) ceramic
capacitor and a 100 uF electrolytic capacitor
 IMG_3840.jpegIMG_3847.jpeg 
  17203   Fri Oct 21 10:37:36 2022 AnchalSummaryBHDBH55 phase locking effortsAfter the amplifier was modified with a
capacitor, we continued trying to approach
locking LO phase to in quadrature with AS
  
  17204   Fri Oct 21 16:15:10 2022 yutaSummaryBHDLO phase locking with BH55 audio dither trials[Paco, Yuta]

We are still struggling with locking
LO phase in MICH or ITM single bounce with
 Screenshot_2022-10-21_15-33-18_LO_OLTF_LO1_BH55_Q.pngScreenshot_2022-10-21_15-42-50_LO_OLTF_LO1_BHDCDIFF.pngScreenshot_2022-10-21_15-44-53_MICH_OLTF.pngScreenshot_2022-10-21_15-50-43_LO_OLTF_LO1_BH55_Q_MICH.pngScreenshot_2022-10-21_16-11-16.png 
  17205   Sat Oct 22 21:36:28 2022 ranaSummaryBHDBH55 phase locking effortsgive us an animated GIF of this cool new
tool! - I'm curious what happens if you
look at 2 DoF of the same suspension. Also
  
  17206   Mon Oct 24 18:01:00 2022 PacoSummaryBHDBHD actuation measurements[Yuta, Paco]

Today
we calibrated the actuation on BHD suspended
 OLTF_LOPhaseLocking_ITMYSingleBounce.pngActuationRatio_ITMY_AS1_AS4_LO1_LO2.png 
  17208   Tue Oct 25 08:25:00 2022 JCUpdateBHDBHD fringe aligned with reduced LO and AS beam clippingI aligned today using this scheme. I couldn't
seem to get C1:IOO-MC_TRANS_SUM above
13400 by using WFS or manually aligning.
  
  17212   Tue Oct 25 17:27:11 2022 PacoSummaryBHDLO phase control with RF + audio sidebands[Yuta, Paco]

Today
we locked LO phase with BH55 + Audio dithering
 Screenshot_2022-10-25_17-36-45_LOPHASELOCKED.pngScreenshot_2022-10-25_17-33-33_LOPHASELOCKING_MICHBHD_ELP80_280HzDither.png 
  17216   Wed Oct 26 16:04:12 2022 PacoSummaryBHDLO phase control with RF + audio sidebands[Yuta, Paco]

Today
we again locked the LO phase with BH55 +
  
  17228   Thu Nov 3 20:07:01 2022 AnchalSummaryBHDAS1 coil balancing required[Anchal, Koji]

The LO phase lock that was achieved
lasts for a short time because as soon as
  
  17236   Mon Nov 7 17:10:41 2022 AnchalSummaryBHDQPD installation seems like lost causeThe new QPD installation is turning out
to be much more hard than it originally seemed.
After finsing the cable, QPD and interface
  
  17265   Mon Nov 14 17:45:02 2022 yutaUpdateBHDBHD DC PD unwhitening and removing cables to c1lsc[Paco, Yuta]

We removed splitter to route BHD DC
 Screenshot_2022-11-15_13-08-17.png 
  17268   Tue Nov 15 17:08:59 2022 PacoUpdateBHDRequest for estimates[Yehonathan, Yuta, Paco]

We would like to estimate:


LO phase sensitivty (for
  
  17270   Tue Nov 15 19:00:56 2022 yutaSummaryBHDMICH locked with balanced homodyne readout at some LO phase[Paco, Yuta]

MICH
was locked with BHD DCPD A-B signal with
 Screenshot_2022-11-15_18-34-25_MICHBHDLocked.pngScreenshot_2022-11-15_19-02-02_MICHLine.pngScreenshot_2022-11-15_18-38-20_BHDMICHOLTF.png 
  17273   Wed Nov 16 15:09:08 2022 yutaUpdateBHDBHD fringe contrast measured with unwhitening filtersBHD fringe visibility was measured again
with unwhitening filters on on BHDC_A and
B, which removed signal leakage to zero (
 ContrastMeasurements20221116_edited.pdf 
  17274   Wed Nov 16 18:41:17 2022 yutaSummaryBHDOptical gain calibrations for BHD MICHOptical gains of AS55 and BH55 are calibrated
for BHD MICH.

LO-ITM single bounce:
 Screenshot_2022-11-16_18-57-12.pngScreenshot_2022-11-16_18-49-53_BHDMICHCalLines.pngLSC-AS55_Q_ERR_DQ_1352689642.png 
  17279   Thu Nov 17 14:12:58 2022 yutaSummaryBHDOptical gain calibrations for BHD MICH with lower UGF[Paco, Yuta]

We found that MICH UGF was unexpectedly
 Screenshot_2022-11-17_14-39-17_MICHLOPHASEOLTF.pngScreenshot_2022-11-17_14-41-40_LowUGFConfiguration.png 
  17282   Thu Nov 17 20:02:10 2022 yutaSummaryBHDMICH optical gain measurements with different LO phasesMICH
optical gain was measured with different
LO phases over ~90 degrees.
 UncalibratedMICHOpticalGainVSLOphase20221117.pngCalibratedMICHOpticalGainVSLOphase20221117.png 
  17284   Fri Nov 18 13:05:00 2022 yutaSummaryBHDGains adjusted for bandstop filters for BHD optics[Paco, Yuta]

We realized that bandstop filters
 Screenshot_2022-11-18_13-16-31_AS1ViolinFilters.png 
  17285   Fri Nov 18 16:58:39 2022 yutaSummaryBHDActuator calibrations for MICH BHDAs there is some confusion in actuator
calibration, we have done the measurement
again from scratch.
 7x 
  17287   Fri Nov 18 22:46:02 2022 yutaSummaryBHDMICH optical gain measurements with different LO phases, with signsMICH
optical gain with a sign was measured with
different LO phases over ~180 degrees, with
 UncalibratedMICHOpticalGainVSLOphase20221118.pngCalibratedMICHOpticalGainVSLOphase20221118.png 
  17294   Mon Nov 21 17:44:00 2022 yutaSummaryBHDMICH BHD displacement sensitivity with AS55_Q and BHD_DIFF[Paco, Yuta]

MICH displacement sensitivity was
compared under AS55_Q locking and BHD_DIFF
 Screenshot_2022-11-21_17-33-20_OLTF.pngScreenshot_2022-11-21_17-45-25_MICHBHDDisplacement.png 
  17296   Mon Nov 21 18:43:46 2022 yutaUpdateBHDc1hpc and c1lsc modified to send BHD_DIFF and BHD_SUM[Anchal, Yuta]

To send BHD signals from c1hpc after
 Screenshot_2022-11-21_18-42-49_BHD.png 
  17301   Wed Nov 23 11:06:08 2022 AnchalUpdateBHDc1hpc and c1sus modified to add BS dither and demodulation optionc1hpc has option of dithering BS now (sending
excitation to BS LSC port to c1sus over IPC).
This is available for demodulating BHDC and
  
  17302   Wed Nov 23 12:58:33 2022 YehonathanUpdateBHDSome more calculationsChanged the BHD BS transmissivity to 0.56.

Demodulation Phases

As was noted before. The LO phase
 LO_phase_sens_vs_LO_phase_RF.pdfLO_phase_sens_vs_LO_phase_RF_fixed_demod.pdfLO_phase_sens_vs_MICH_Offset.pdf 
  17303   Wed Nov 23 14:59:11 2022 PacoSummaryBHDBHD_DIFF sensitivity to BS dither with MICH Offset[Yuta, Paco, Anchal]

We measured

(a)
 BHDIFF_rand_SensvsMICHOffset.pdf 
  17308   Wed Nov 23 17:28:39 2022 YehonathanUpdateBHDSome more calculationsFields at the BHD BS. More on this later.  Fields_at_BHDBS.pdf 
  17309   Wed Nov 23 20:58:23 2022 yutaSummaryBHDBHD_DIFF sensitivity to BS dither with MICH Offset with different BH55 demodulation phases[Anchal, Paco, Yuta]

Attachment #1 is the same plot as 
 BHDIFF_rand_SensvsMICHOffset_pydemod.pdfBHDIFF_rand_SensvsMICHOffset_pydemod_NoMICHinBH55Q.pdfBHDIFF_rand_SensvsMICHOffset_pydemod_BH55at70deg.pdfMICHBHD_BH55.pdf 
  17317   Mon Nov 28 16:53:22 2022 AnchalSummaryBHDF2A filters on LO1 LO2 AS1 and AS4[Paco, Anchal]

I changed the script in /opt/rtcds/caltech/c1/Git/40m/scripts/SUS/outMatFilters/createF2Afilters.py
  
  17319   Mon Nov 28 18:21:50 2022 PacoSummaryBHDBH44 prepI checked the LSC rack to evaluate what
we might need to generate 44 MHz rf in the
hypothetical case we go from BH55 to BH44
  
  17322   Tue Nov 29 15:32:32 2022 AnchalUpdateBHDc1hpc model updates to support double audio ditherMany changes have been done to c1hpc to
support dual demodulation at audio frequencies.
We moved away with ASS style of lockin setup
 Screenshot_2022-11-29_15-36-05.png 
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