J. Kissel, J. Rollins

We're putting the final touches on the estimate of the uncertainty on the calibrated data stream, and have found that my factors of 3x and 4x reduction of the low frequency calibration line heights on 2023-03-30 (LHO:68289) were a little but too much of a reduction given the current status of ER15 noise, which we assume will be representative of early O4 noise. We intend for the uncertainty in the transfer function for each of the calibration lines to be less than 0.5%*** (as computed by sqrt( (1 - C) / (2 N C) ) -- where N = 13 averages using an "FFT Length," i.e. a DEMOD low pass filter with time constant of 10 sec). We've found that the uncertainty is regularly 0.8 to 1.0%, and not because of glitches in the detector noise.

As such, I've increased the amplitude of the H1 SUS ETMX UIM (L1) and PUM (L2) 15.6 and 16.4 Hz Calibration Lines,
                                         O3-era      Mar 30      May 12       May/Mar ratio       May / O3 ratio
    H1:SUS-ETMX_L1_CAL_LINE_CLKGAIN       75.0        20.0        35.0          1.75x                0.46x
    H1:SUS-ETMX_L2_CAL_LINE_CLKGAIN      120.0        35.0        50.0          1.43x                0.41x

Attachment 3 shows how the uncertainty has improved over time with this increase in amplitude compared against 0.005, or 0.5%.

The first two attachments show what needs changing, and their acceptance in the SDF system.

*** 0.5% is, as with a lot of how the uncertainty on the time-dependent correction factors, an arbitrary threshold. The threshold was set in O3 as "when the uncertainty in the TDCFs is larger that 0.5%, then it's starting to 'substantially' impact / dominate the overall response function uncertianty, i.e. the overall uncertainty in the calibrated data stream." Where 'substantially' is defined by thinking about what the uncertainty in the calibration is at ~20 Hz == in O3 this was around 5% == so a factor of ten less than that is 0.5%. Also, since no one likes a "measurement" or "statistical" uncertainty to "dominate" an uncertainty budget (can you hear folks asking "wait, why don't you just integrate for longer?"), we increase the amplitude of these lines.

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; THIS ALOG previously changed Apr 2023 (LHO:68289)
16.4        ETMX PUM (L2) SUS      \kappa_PUM excitation        H1:SUS-ETMY_L2_CAL_LINE_FREQ          Amplitude Change; THIS ALOG previously changed 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        Moved from PCALX 410.2 to PCALY 284.01 LHO:69354
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])

Naoki, Vicky

To run FC ASC with both WFS (which aligns the FC cavity axis to the injected beam using FC_WFS aka RLF_QPD) and beam spot control (which aligns the FC injection axis to a green trans QPD in FCES, FC_TRANS_A, LHO:69374), we have now adjusted the time constants of these two loops and engaged them in guardian accordingly so they don't fight each other. This involves using the -20dB (gain(0.1)) filter in H1:SQZ-FC_ASC_INJ_ANG_P/Y filter banks, now in FM7. The -20dB FM7 filter has been saved in SDFs.

FC WFS ~ 30 seconds (here), FC beam spot control ~ 15 minutes (900 s, here)

FC guardian's "FC_ASC_ON" state now first turns on FC_WFS ASC (FC_CAV_POS/ANG_P/Y), waits 20 seconds to let the FC axis align, then turns on the ASC inputs to the beam spot control filter banks (FC_ASC_INJ_ANG_P/Y). This has been uploaded to FC guardian, and committed to SVN #25626.

Together, you can see the trends of how FC ASC is engaged here. First, FC_WFS aligns the FC axis for 30 seconds (top), then FC beam spot control spends 15 minutes aligning ZM3 to the FC-GR TRANS QPD pitch/yaw beam spot in FCES (bottom), over which time the cavity axis follows the injection axis moving accordingly.

We did a detchar hardware injection test around GPS 1367955315.

The status bit correct identified the presence of the injection.  However, it seems that a very long impulse response in the one of the H1CAL-INJ_TRANSIENT filter banks caused a signal to persist for many minutes after the excitation ended, which is why the blue STATUS channel above remained high out to about 20m even though the injection effectively stopped at around 15m.  Will need to interact with the calibration group to address that issue, and/or have the injection script clear the filters and shutoff the output after the excitation is done.

I also note the GraceDB upload failed, so there's some sort of auth issue that will need to be resolved there.

It appears that the current damping settings are ringing up ITMY mode 5, and having no effect on mode 6. I am turning off the damping gain for now.

Naoki, (Nutsinee remotely), Vicky

We've had issues transitioning the filter cavity IR locking this week, and we've so far tracked it down to the combination of this week's computer restarts, the addition of FC beam spot control last week (LHO:69374), and LVEA temperature drifts. Our computer issues this week seem to be because we were not monitoring our ZM+FC P/Y slider offsets in SDF, especially we were not monitoring most of these in safe.snap. We are now monitoring all ZM{1,2,3,4,5,6} and FC{1,2} P/Y slider offsets in safe.snap and in OBSERVE.snap, see attached screenshots of accepted SDF's.

Longer story of what we think happened: Computer restarts caused SQZ+FC alignments to come back online quite misaligned, with both SQZ-->IFO and SQZ-->FC misaligned, and so our SQZ LO OMC locking was unreliable, which causes the FC-IR lock handoff to fail. SQZ-ASC (on AS42) would try to realign squeezer to IFO, but at the same time FC ASC would engage, and further confused all the FC+IFO SQZ ASC. Nutsinee finding the LO struggle to lock on OMC helped find the SQZ-ASC as a problematic thing, which helped track down the ZM restart issues. Overall, this resulted in each FC-IR locking attempts aligning the whole system slightly more every time it tried to engage ASC, but quickly the FC-IR lock transition would fail in seconds as all the alignment moved, which would bring the squeezer down, and then the whole thing would start over. So, after many re-locking attempts, the incremental alignment improvements each time eventually allowed the whole squeezer alignment to converge after tens of minutes (ie, the squeezer eventually managed to re-align and re-lock itself to the IFO after tens of minutes of trying and making a little progress each time).

ITMY mode08 has been troubling us for the past few days as the nominal settings has stopped working. I have found a new setting which looks to be working (see screenshot attached below) - with a new phase and gain. I need to test this out for a couple of locks before making the changes in lscparams and in the SDF. The new filters and gain are shown below,

New settings: FM1 FM3 FM10,  Gain = 0.01

Old settings: FM1 FM2 FM10, Gain = -0.04

Ryan S, Erik, Fil, Dave:

We continue to have some issues with the CER pulizzi unit, currently it is very slugish in responding to commands. I have added more delays in the IOC code, and an additional scan after each command to verify the outlet status. This seems to work, but has slowed commands to 4 seconds on all units except CER, which takes 8 seconds to complete.

Until we roll out the second units at the end stations, I have taken them off the MEDM and cleaned up the layout (see attachment)

FAMIS23805

Two days ago one of the fan units tripped off in the corner station, some the other vibrometers saw the effects of this coming on and off. Since then fans 1 and 2 have looked more noisy. Outbuilding units show no change.

DriptaB, TonyS, RickS

The following commands were executed to update the calibrations of the Pcal Tx and Rx laser power sensors at both end stations:

caput H1:CAL-PCALX_FORCE_COEFF_RHO_T 8334.52
caput H1:CAL-PCALX_FORCE_COEFF_RHO_R 10692.3

caput H1:CAL-PCALY_FORCE_COEFF_RHO_T 7157.80
caput H1:CAL-PCALY_FORCE_COEFF_RHO_R 10652.5

These changes increase the calibrations of the Pcal sensors (ct/W) by 0.603 % in response to recent calibration of Pcal transfer standards by NIST and PTB in Germany.  Details of the rationale for the update can be found in LIGO-G2300471, slides 13-18.

This change will result in a 0.063% increase in inspiral range (about 0.84 Mpc).

The changes have been accepted in SDF.

As O4 approaches, we will begin running the CW hardware injections soon, perhaps starting next Tuesday maintenance. A crucial part of the injections is calibrating the hardware injection excitation point (note that this calibration may drift, especially if the splitting ratio of the photon calibrator optical follower servo changes, so nominally one would compare the actual injection waveform on the RX or TX PD with the recovered one in strain). I am revisiting the measurements made in LHO aLOG 46848 to update the hardware injection actuation function for CW hardware injections.

As a reminder, the hardware injection path sees the following:
                                                            V              W     N                 1      m     h
[ 61 usec delay x 61 usec delay x AI(d) x 61 usec delay x ----- x AI(a) x --- x --- x sus.norm x ----- x --- x --- ]
                                                           cts             V     W                f^2     N     m

The terms AI(d), AI(a) are the known digital and analog anti-imaging transfer functions, respectively, that we can model in pyDARM; sus.norm, 1/f^2, and m/N are pieces from the SUS dynamical model for the L3 stage of the QUAD suspension; N/W is the watts-to-force transfer coefficient 2*cos(theta)/c where theta is the angle of incidence and c is the speed of light in a vacuum; V/cts is the DAC calibration for the Pcal system 20 V / 2^18 cts; and h/m is the strain per meters, essentially 2/(L_x + L_y). So the remaining term we need to know is the watts per volt of the photon calibrator.

Historically, I calculated this value through a series of calculations and a single transfer function measurement (e.g., LHO aLOG 46846), but now this is a lot simpler due to some front end improvements. Now I can take a transfer function measurement and get the results directly from that measurement H1:CAL-PCALX_TX_PD_WATTS_OUT / H1:CAL-PCALX_OFS_PD_OUT_DQ, using 10 averages and BW setting of 0.1 Hz.

Attached is a screenshot of that transfer function, where I zoomed in on one of the systematic error calibration lines, 77.73 Hz. The coherence at the closest bin, 77.75 Hz is very high (>0.9999) and the resulting transfer function magnitude is 0.136778 W/V. Compared to the previous value of 0.13535, this is a change of just over 1%.

I then used an up-to-date pydarm_H1.ini file with this new value for pcal_etm_watts_per_ofs_volt = 0.136778 to generate an actuation function file attached to this aLOG. The main difference is the new calibration of the W/V value and to remove a DC scaling of the AI(a) of 0.99. These two effects combine to change the DC calibration of the excitation point by 2%.

The next step, not yet done, is to update the CAL INJ filter bank values with updated numbers in the filter banks FM6 antiAIaGain (change to 1.0) and FM7 cts/N (change to 1.4539e13). I am not sure the current value in the FM3 N/m value is correct, if I calculate the m/N value at 1 Hz for the x-arm TST stage, I get a value of 0.00156554 m/N ==> 638.75611903 N/m, which is significantly larger than the current value of 382.954.

I went through the hardware injection screens (CAL_INJ_CONTROL2, PCAL_END_EXC) and cleaned them up based on the way that we're now handling hardware injections

• The INJ_TRANS guardian node was decommissioned, so references to that node were removed from the screen
• The old status bits that were controlled by the INJ_TRANS node were also removed
• The STATUS indicator bits were fixed to reflect their proper
• removed some inaccurate/misleading indicators in the PCAL_END_EXC screen

I then did some test injections and confirmed that all the status bits were working as expected.  Here's an example of the screen with an active "detchar" injection (as labeled by the H1:CAL-INJ_TINJ_TYPE record):

The H1:CAL-INJ_STATUS bit word (purple indicators) behaved correctly, and reset appropriately when the EXC was stopped.

Two stages of whitening were enabled for the OMC-REFL_A photodetector.

The slow controls DC readout is very close to +10V and sometimes saturates. The fast DAQ has more headroom and should be fine. If not the analog PD gain should be reduced to 10dB.

PS. OMC_REFL_A is using the old DCPD whitening chassis: Only the 24dB gain step works, all others will short the output. Filter stage 2 is not a whitening stage. 

Fri May 12 10:08:09 2023 INFO: Fill completed in 8min 9secs

Laser Status:

NPRO output power is 1.819W (nominal ~2W)

AMP1 output power is 68.61W (nominal ~70W)

AMP2 output power is 135.7W (nominal 135-140W)

NPRO watchdog is GREEN

AMP1 watchdog is GREEN

AMP2 watchdog is GREEN

PMC:

It has been locked 2 days, 21 hr 30 minutes

Reflected power = 15.87W

Transmitted power = 109.9W

PowerSum = 125.8W

FSS:

It has been locked for 0 days 0 hr and 8 min

TPD[V] = 0.8636V

ISS:

The diffracted power is around 2.5%

Last saturation event was 0 days 0 hours and 17 minutes ago

Possible Issues:

PMC reflected power is high

TITLE: 05/12 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Lock Acquisition
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 8mph Gusts, 5mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.17 μm/s
QUICK SUMMARY: IFO was in Locking_Arms_Green since 12:44 UTC (~2 hrs and 20 mins) when I arrived (with log asking to find X ALS by hand).