Sat May 06 10:05:20 2023 INFO: Fill completed in 5min 19secs

TITLE: 05/06 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Calibration
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 3mph Gusts, 1mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.12 μm/s 
QUICK SUMMARY:

- IFO was locked at NLN for 1:13 (acquired at 13:41 UTC)

- All observe SDFs are cleared, so I flipped the intention bit to OBSERVING @ 14:46 UTC

- CDS/SEI/FOM/DMs all look good

Tito Dal Canton from PyCBC reported that there are periods with many ADC overflows of the DCPD in the last few days. This is probably due to the increased DARM offset alog 69358. See attached plots of the DQ vector. There's no obvious effect on the spectrum or the glitchiness, so it must not be a severe overflow. But at least some of the searches are using this as a veto and aren't analysing the data.

• Whitening gain on POP45 reduced by 6dB (alog 69350)
• DARM offset increased from 20mA to 40mA (alog 69358)
• SCRL offset changed to -265 (alog 69373)
• MICH and SRCL ASC changes (alog 69372)

LOCK#1

After the IFO was locked 5h13, we lost lock at 01:06UTC from ASC changes.

Elenna loaded a new MICH filter after the lockloss.

LOCK #2

Had a tough time relocking (later we noticed it seemed like CHECK_MICH_FRINGES moved the BS the wrong way at around 2:00UTC). This BS move made the DIFF beat note too low (-30) for LOCKING_ALS. I attempted an initial alignment. Couldn't get XAMR IR locked eso exited from initial alignment. Reverted BS pointing to before CHECK_MICH_FRINGES and touched PRM during ACQUIRE PRMI. Finally locked again. Inputting 76W at 03:45 UTC and at NLN at 04:20UTC. Delay due to OMC_WHITENING limited needed to be changed, alog69371.

Observing at 04:35UTC. SDFs accepted:

• SQZ sdfs screenshot for FC TRAMP, ZM3 offset, FC detuning and PSAMS;
• LSC and ASC sdf screenshot for alog 69373 and 69372;
• OMC and CAL sdf screenshot for 69375 The OMC TRAMP sdf may need to be re-accepted on next lock as it may been from Elenna manually changing Whitening.

At 05:59UTC we had the 10.4Hz PI ring up (PI # 24), I was notified via verbalalarms and it and was successfully damped by the PI_DAMPING guardian, no intervention needed, Vicky's alog 69318 changes were good. See attached plot.

Louis is starting Calibration Sensing Function as there has been a lot of IFO changes since Corey's alog 69345 measurements, list below. State of IFO before measurement attached.

• Whitening gain on POP45 reduced by 6dB (alog 69350)
• DARM offset increased from 20mA to 40mA (alog 69358)
• SCRL offset changed to -265 (alog 69373)
• MICH and SRCL ASC changes (alog 69372)

Naoki, Vicky

We successfully implemented the beam spot control with green QPD at FC trans by feeding back to ZM3 (Fig.1). The middle two are the green QPD P/Y signals and the bottom two are the error signals of the beam spot control P/Y. The cursors show the optimal green QPD offset for FC2 center which is decided in alog69338. After engaging the control, the green QPD signals settle to the optimal offset and the error signals become 0. The time scale of this control is ~1 min.

Fig. 2 shows the medm of FC ASC and Fig. 3-6 show the input/output matrix of FC ASC.

For stable FC green and IR lock with the beam spot control, we needed to clear history of filter bank of the beam spot control when the FC loses lock. Vicky added the clear history in down state of SQZ_FC guardian. The FDS with the beam spot control can be operated well by guardian.

Elenna, Camilla, Vicky,

In our relock with OMC whitening changes (69350) PLUS a higher DCPD sum (69358), ICS lock kept us at OMC_WHITENING with the message "Violins are too high for whitening" but comparing violin levels (500Hz Violins on DARM were 4 x 10^-16 m/Hz^1/2 ) and DCPD levels in the last lock we realized we would be fine.

Elenna manually turned on the whitening and manualled us to NLN. Elenna updated the ISC_libary.check_for_violins_saturation(power='high') checker from her guesstimated factor of 6 (worked with higher whitening before higher DCPD offset) to a factor of 3.

DCPD signals with T-cursor when whitening turned on attached.

I have updated the SRC2 and MICH ASC controllers and cutoffs. The SRC2 P and Y controllers are the same that are applied to PRC2, with previous success (see 69108).

The MICH controllers are very different than before. I measured the MICH P olg recently and found it had a 2 Hz bandwidth, which seems high. The new controller reduces the bandwidth to 0.6 Hz. This allows us 24 dB less noise injection from 10-20 Hz. The MICH loops are now significant contributors to the ASC sub budget, so will be a significant improvement to ASC noise.

There is much more 0.5 Hz motion in the MICH P loop with this new controller engaged. The new loop has 16 dB of gain margin, so I increased the gain by 6 dB. There is still more 0.5 Hz motion than we are used to in MICH. It is not unstable. I will look into adjusting this loop design so we can improve the suppression at 0.5 Hz further but maintain some of the improved cutoff at 10 Hz. The MICH Y loop looks fine, although it also shows increased low frequency RMS.

All of these controllers are now guardianized. SRC2 is engaged in ENGAGE_ASC with the new controller and cutoff. The MICH loop is turned off briefly in OFFLOAD_DRMI to switch from AS 45 to AS 36, so I use that moment to switch over to the new controller and cutoff. I then increase the MICH P gain in PREP ASC to further suppress the 0.5 Hz motion.

In MICH P, FM7 now replaces FM8 and 10. In MICH Y, FM5 replaces FM7 and FM10. IN SRC2 P and Y, FM6 replaces FM7 and 9.

There is possibly small improvement in DARM between 10-20 Hz, but with all the other changes today, it is hard to tell.

Vicky, Camilla.

H1:SQZ-SHG_PZT_VOLTS is going from 55V to zero over ~40 hours, plot attached. In alog 68568 Vicky notes that when SHG PZT ran out of range, SQZ_MANAGER handles it fine, taking SQZ out of the IFO, relocking everything before re-injecting SQZ.  But to minimize this happening during long locks we've added a checker in LOCK_SHG and SQZ_READY_IFO to check if H1:SQZ-SHG_PZT_VOLTS < 15, return LOCK_SHG and take the SQZ_SHG guardian to DOWN back to LOCKED, which puts the PZT voltage in the middle of it's range.

Jennie, Jenne, Vicky, Camilla

After setting the DARM offset to 40mA I took another set of SRC tuning measurements, where I changed the SRCL1 offset and measurement the sensing function at low frequencies with Craig's noise_recorder functions. Data folders and figure folders are listed in the table and the sensing function measurements for each are attached in order of detuning (whereas the table is in time order). The first measurement was done when we were around 2hr 51 mins thermalised and the -265 count measurement when we were 3hrs 52 mins into lock. Camilla and I picked out this offset as giving the flattest sensing function (ie. no detuning). I want to do some smoothing of the data tomorrow to make it clearer, however.

To run the DARM injection use noise_recorder/code/darm_noise_injection_caller.py

To run the PCAL to DARM measurement use noise_recorder/code/pcal_noise_injection_caller.py

To process use noise_recorder/code/darm_sensing_function_processor.py

To plot all sensing functions use noise_recorder/code/darm_sensing_spring_comparison.py, which is the png attached.

Jennie, Naoki, Jenne, Elenna, Vicky

We took more measurements of 40mA vs. 20mA on the OMC SUM DCPD (that is, the DARM offset).

This is because our previous measurements did not correct DARM by the calibration at high frequencies, as the PCAL > DARM broadband transfer functions had low coherence at these frequencies.

The technique above 500Hz is thus to take a DARM ASD spectra and correct it by the peak height of the 1083 Hz PCAL line.

Measurement 1:

21:16:43 UTC

20mA (in OBS), so squeezing injected.

Ref0

Measurement 2:

21:38:42 UTC

20mA (IN COMMISSIONING), no squeezing.

Ref1

Measurement 3:

21:52:24 UTC

40 mA (IN COMMISSIONING), no squeezing.

Ref2

Measurement 4:

22:08:09 UTC

40mA (IN COMMISSIONING), squeezing injected.

Ref3

The measurements are saved in /ligo/home/jennifer.wright/git/DARM_offset/2023-05-05_2114UTC_H1_DARMSPEC.xml.

Attached are the scaled spectra (courtesy of Jenne).

Since the noise looks lower between 40mA no squeeze(brown) and 20mA no squeeze (green), we will go with this offset.
 

We are not sure why the 40mA, squeezer on trace looks so bad at low frequencies. There's not a way for the homodyne angle to produce the given change in the squeezing blue/pink traces, so that is likely the effect of something else on the squeezing. The most relevant comparison should be the no-squeezed DARM traces at different homodyne angles, green vs. brown. 

After the IFO was locked 5h13, we lost lock at 01:06UTC from ASC changes. Had a tough time relocking (seemed like CHECK_MICH_FRINGES moved the BS the wrong way..) but now past ENGAGE_ASC_FOR_FULL_IFO.

Daniel Nutsinee

Added a new ADF OSC screen to the ADF overview.

With the DARM offset moving to 40mA total DCPD photocurrent (69358), this should correspond to an IFO readout angle of about -12 degrees, given the 1.7mA contrast defect (69361).

Using Craig's calculation of the homodyne / readout angle (65000), as a function of DCPD power level for a 1.7 mW of junk light (68859, 69361),

total_dcpd_light = 20  #mA     # total dcpd mA level
contrast_defect = 1.7  #mA     # this is a recently measured value
darm_offset_power = total_dcpd_light - contrast_defect
homodyne_angle = np.arctan2(np.sqrt(contrast_defect), np.sqrt(darm_offset_power))  #radians
homodyne_angle*180/np.pi    #degrees

Here's the resulting homodyne angle for various DCPD powers:

Attached here are some gifs of gwinc-calculated quantum noise for DARM with NO squeezing, rotating through some homodyne angles. The following NO-SQZ GPS times were used:

J. Betzwieser, D. Bhattacharjee, J. Kissel, R. Savage

Executive summary: More changes to calibration lines in order to commission the best answer out of the PCALXY comparison.

Based on the systems level compromises discussed on Friday last week about having the PCALX contribution to the PCALXY comparison right next to the 410.3 Hz PCALY line that's used for TDCFs (LHO:69175), I moved the PCALX comparison line from 410.2 Hz (0.1 Hz below 410.3 Hz) to 409.8 Hz (0.5 Hz below 410.3 Hz). LHO:69303. 

After looking at the results from that move to 409.8 Hz, Joe, Rick, and Dripta re-discovered that there's a notch in the DARM loop at 410.3 Hz (see LHO:48530), which is a relatively wide elliptic bandstop (whose boundaries are 409.4 and 411.2 Hz, i.e. 410.3 +/- 0.9 Hz). That means the frequency response change of IFO's response function, C / (1 + G), is changing quite rapidly between the two 410.3 and 409.8 Hz frequencies. *That* means that the traditional, easy, side-by-side PCALXY comparison of lines to arrive at a ratio of amplitudes -- which assumes that the response function ratio isn't changing between frequencies -- becomes harder, and loop model dependent.

As such, yesterday, Joe, Rick, and Dripta got together and posted the proposal outlined last night LHO:69331, to move the lines that inform the PCALXY comparison entirely away from 410.3 Hz, such that the comparison is between
     H1:CAL-PCALX_PCALOSC8_OSC_FREQ    283.91       Already present as a "Systematic Error" line, but now louder, increasing amplitude from 200 to 2000 cts.
     H1:CAL-PCALY_PCALOSC4_OSC_FREQ    284.01       New PCALY line dedicated to this test, set with an amplitude of 1430 cts 

I've implemented their proposal at of 2023-05-05 20:00 UTC.

Knock-on effects:
    - Because there's a new line on PCALY, I wanted to check whether we still have enough OFS range to drive the temporary, ER15 "thermalization" lines, driven by the CAL_AWG_LINES guardian. We do, so we're good there.
    - The new addition of 284.01 Hz PCALY *may* impact (bias) the demodulation (answer) of the 283.91 Hz PCALX systematic error line, given that that line's front-end DEMOD still uses a +/- 0.1 Hz wide SIG band pass, and 0.1 Hz corner frequency low pass, i.e. a 10 second FFT.
    - Because the systematic Error line is much louder, and has a new companion, equally loud "next door," the CW searches may be more likely to complain about sidebands and non-linearities not subtracted out.
    - Because I'm using a new PCALY oscillator, I need to double check that the GDS pipeline still safely subtracts this out in the GDS-CALIB_STRAIN_NOLINES channel.
    - This renders the DEMOD10 PCALX non-functional, since it's stuck demodulating the 409.8 Hz PCALX line that isn't there. Ideally, we'd convert PCALX DEMOD 10 to watching the new 284.01 Hz PCALY line, but that would require a front-end code change. Eventually, once we're done the 24.5 Hz PCALY thermalization line, then we can switch that PCALY DEMOD 4 over to using that. 

Things that need to change in order to accommodate this move:
    (1) Accepted new oscillator settings in h1calex and h1caley SDF systems.
    (2) Modified the pydarm_H1.ini parameter file which now is up to version marked by git hash 156230c7. Parameters cal_line_cmp_pcalx_frequency and cal_line_cmp_pcaly_frequency have changed.
    (3) Pushed new DARM_ERR / PCAL and DELTAL / PCAL EPICs records at these line frequencies with the updated parameter file, using the command
        $ pydarm export --push --epics-only --model /ligo/groups/cal/H1/ifo/pydarm_H1.ini
    (4) Accepted them in h1calcs SDF.

Rick said he's going to take care of modifying the DEMOD SIG and low pass filters for the X Y comparisons as he needs.

Here's the latest list of calibration lines:
Freq (Hz)   Actuator               Purpose                      Channel that defines Freq             Since O3
15.6        ETMX UIM (L1) SUS      \kappa_UIM excitation        H1:SUS-ETMY_L1_CAL_LINE_FREQ          Amplitude Change on Apr 2023 (LHO:68289)
16.4        ETMX PUM (L2) SUS      \kappa_PUM excitation        H1:SUS-ETMY_L2_CAL_LINE_FREQ          Amplitude Change on Apr 2023 (LHO:68289)
17.1        PCALY                  actuator kappa reference     H1:CAL-PCALY_PCALOSC1_OSC_FREQ        Amplitude Change on Apr 2023 (LHO:68289)
17.6        ETMX TST (L3) SUS      \kappa_TST excitation        H1:SUS-ETMY_L3_CAL_LINE_FREQ          Amplitude Change on Apr 2023 (LHO:68289)
33.43       PCALX                  Systematic error lines       H1:CAL-PCALX_PCALOSC4_OSC_FREQ        New since Jul 2022 (LHO:64214, LHO:66268)
53.67         |                        |                        H1:CAL-PCALX_PCALOSC5_OSC_FREQ        Frequency Change on Apr 2023 (LHO:68289)
77.73         |                        |                        H1:CAL-PCALX_PCALOSC6_OSC_FREQ        New since Jul 2022 (LHO:64214, LHO:66268)
102.13        |                        |                        H1:CAL-PCALX_PCALOSC7_OSC_FREQ           |
283.91        V                        V                        H1:CAL-PCALX_PCALOSC8_OSC_FREQ           V
284.01      PCALY                  PCALXY comparison            H1:CAL-PCALY_PCALOSC4_OSC_FREQ        TURNED ON THIS ALOG
 ----       PCALX                  PCALXY comparison            H1:CAL-PCALX_PCALOSC2_OSC_FREQ        TURNED OFF THIS ALOG
410.3       PCALY                  f_cc and kappa_C             H1:CAL-PCALY_PCALOSC2_OSC_FREQ        No Change
1083.7      PCALY                  f_cc and kappa_C monitor     H1:CAL-PCALY_PCALOSC3_OSC_FREQ        No Change
n*500+1.3   PCALX                  Systematic error lines       H1:CAL-PCALX_PCALOSC1_OSC_FREQ        No Change (n=[2,3,4,5,6,7,8])

Unfotunately turning off the cosmic ray power supply did not remove the intermittent 4.05 Hz bumps in DARM, even though all the CS signals that showed a large peak at 4.06 Hz are now clean.

Looking again at all the signals that contain a peak around 4.05 Hz, we now have

          H1:PEM-CS_MAG_LVEA_VERTEX_Z_DQ 4.050 Hz
               H1:PEM-EX_ADC_0_08_OUT_DQ 4.040 Hz
               H1:PEM-EX_ADC_0_09_OUT_DQ 4.040 Hz
          H1:PEM-EX_LOWFMIC_VEA_FLOOR_DQ 4.040 Hz
         H1:PEM-EX_MAG_EBAY_SUSRACK_Y_DQ 4.040 Hz
         H1:PEM-EX_MAG_EBAY_SUSRACK_Z_DQ 4.040 Hz
             H1:PEM-EX_MIC_EBAY_RACKS_DQ 4.040 Hz
      H1:PEM-EX_TEMPERATURE_BSC9_ETMX_DQ 4.040 Hz
       H1:PEM-EX_VMON_ETMX_ESDPOWER18_DQ 4.040 Hz
               H1:PEM-EY_ADC_0_14_OUT_DQ 4.040 Hz
         H1:PEM-EY_MAG_EBAY_SEIRACK_X_DQ 4.040 Hz
         H1:PEM-EY_MAG_EBAY_SEIRACK_Y_DQ 4.040 Hz
         H1:PEM-EY_MAG_EBAY_SEIRACK_Z_DQ 4.040 Hz
         H1:PEM-EY_MAG_EBAY_SUSRACK_X_DQ 4.040 Hz
         H1:PEM-EY_MAG_EBAY_SUSRACK_Y_DQ 4.040 Hz

Attached plots shows spectra and time series. Although the frequency of all peaks is very close, EX signals are only coherent among themselves, and not with EY signals, and the other way around too. So it looks like at both end stations there is a source of 4.04 Hz that is local. Maybe a clue? Still, we don't have evidence that those sources are related to the DARM noise.