J. Kissel

We continue to check off ideas on the list trying to answer the question "why did the new DARM loop filtering configuration work in Dec 2023 (LHO:74977), not work in Jan 2024 (LHO:75308), and now works again in Mar 2024 (LHO:76315)?" 

One of the ideas was that the ESD actuation strength had drifted due to charge accumulation between Dec 2023 and Jan 2024. We suspected this because
    (1) First, the trend of TST stage actuation strength sweeps from https://ldas-jobs.ligo-wa.caltech.edu/~cal/?report=20240311T214031Z page 13 -- attached here for convenience -- shows the TST stage has an 8% increase in transfer function magnitude since the last validated report Oct 27 2023 (20231027T203619Z).
    (2) Just before the update to the calibration on Monday 2024-03-11 (LHO:76271), \kappa_TST reported a similar value of 1.08 +/- 0.01. (Remember,  \kappa_TST is the time-dependent correction factor that tracks the TST stage actuation strength relative to the last time the calibration was updated.)

However, I attach a trend of the following between Dec 2023 and Mar 2024:
    - The \kappa_TST value, H1:CAL-CS_TDEP_KAPPA_TST_OUTPUT
    - The ISC_LOCK guardian state number H1:GRD-ISC_LOCK_STATE_N (600 is NOMINAL_LOW_NOISE, 711 is the "new DARM loop filter scheme")
    - the ESD high voltage driver's analog readback of the ESD bias channel H1:SUS-ETMX_L3_ESDAMON_DC_OUT16

Two things are visible:
    (a) Due to our regime of flip-flopping the bias from 
        - "positive 1/4 bias" value of 130 [V_ESD] in NOMINAL_LOW_NOISE to 
        - "negative full bias" value of -430 [V_ESD] in PREP_FOR_LOCKING
        during normal observation run time, the ESD actuation strength did not change between Dec 2023 and Jan 2024. So, this rules out the actuation strength change as a reason for "works in Dec 2023, but not in Jan 2024."

    (b) My guess is that the ESD actuation strength increased by 8% because we had left the IFO in PREP_FOR_LOCKING from Feb 27 2024 to Mar 08 2024, and then again from Mar 09 to Mar 11, for a total of ~2 weeks time at the "negative full bias."

Important to note -- even though \kappa_TST was reset to 1.00 after Monday, Mar 11 2024, update to calibration (or "push" of the most recent measurement of the calibration parameters to CAL-CS / GDS) the ESD actuation strength itself did not change. An 8% increase in ESD actuation strength should still be important to account for in any filter designs of the DARM actuation distribution filtering on ETMX (colloquially referred to as "the cross-overs"), and *now* (in Mar 2024) may result in some differences from when the filters were last designed, or rather on the data the DARM model was based on (from Oct 2023). 

BUT -- Louis' success in the past two nights may indicate that the Dec 2023 design (that uses data from Oct 2023) is not that sensitive to the 8% ESD actuation strength increase, ruling it out as a reason for why the new DARM filter scheme didn't work in Jan 2024, but worked in Dec 2023 and works now in Mar 2024.

One might argue that we should
   (i) Measure the ESD actuation strength via other methods (i.e. "optical lever" and/or "in-lock" charge measurements, or measuring BSC-ISI ST2 drive coupling to DARM noise) to see if we can corroborate the increase in actuation strength and/or see if it's impacting the IFO.
   (ii) For now, do as LLO does and "match the IFO to the calibration model" and adjust the *digital* gain of ESD actuation strength to invert the real ESD actuation strength (typically done by adjusting the H1:SUS-ETMX_L3_DRIVEALIGN_L2L_GAIN).
   (iii) If we find something we don't like in (i), then we should, for a while, operate with *positive* full bias voltage when not in observing.
The conversation about which of these to do is on-going.

Using the low frequency line injections from this morning, we can estimate if the OMC alignment at the time was good. Note that at the time of the test, not all OMC QPD offsets were on.

The first attached plot shows a time series of the OMC QPD signals, and BLRMS in a few bands, computed on OMC-DCPD_SUM. The most interesting is the 410-411 Hz band, which track the amplitude of a DARM calibration line, the one used to compute the optical gain KAPPA_C. We see a clear large modulation of the optical gain with the OMC alignment, and the zero position for all QPD is not the one giving the highest KAPPA_C.

The lines were injected at slighlty different frequencies to map as well as possible the entire 4d space of OMC QPD A and B PIT and YAW. The second plot shows the BLRMS at the DARM calibration line as a function of each QPD vavlue, so four slices in this 4d space. The third plot shows two-dimensional slices, but this is somehow harder to interpreter.

Looking at the second plot, it looks like the optical gain would be improved by moving the QPD values to

QPD_A_PIT 0.1
QPD_A_YAW 0.1
QPD_B_PIT 0.05
QPD_B_YAW -0.07

to maximize the optical gain. Iterative adjustments might be needed. Also, we could inject lines ona single DOF at a time to finetune the offsets

Given our new coherence between DARM and OMC_REFL we looked at the power level on OMC_REFL and AS_C in locks today and before the break.

First attached plot is IM4_TRANS, AS_C, OMC_REFL and the squeezer beam diverter during a time in O4A (~Jan 18). Second plot is the same PDs since the break

IM4_TRANS has 5% less power

AS_C has 4% less power

OMC_REFL has ~16% more power

Edit: I zoomed out and it looks like OMC_REFL was at normal levels in the locks on March 8/9, and higher in the locks on March 11/12 - updated the attached photos to include broader times.

It looks like in the later locks the offsets on the OMC_B QPD were turned off (third plot, sorry my x axis got a bit messed up), so I guess this excess REFL power is just bad alignment.

In lock charge measurements ran 16:31 to 16:47UTC. Last done in January 75362

Leaving SUS_CHARGE requested to INJECTIONS_COMPLETE so that that will run automatically Tuesday 7:45am unless we change it. 

Frequencies of excitations below, we should revisit with the SUS team if these are most appropriate frequencies or too close to bounce modes.

•    'ETMY':12,
•     'ETMX':13,
•     'ITMX':14,
•     'ITMY':15Hz

Wed Mar 13 10:17:28 2024 INFO: Fill completed in 17min 23secs

Gerardo confirmed a good fill curbside.

FAMIS tasks 24873, WP 11771

Procedure checklist for both stations completed.  No issues were identified at this time.

MX: Scroll pump hours: 213.5

       Turbo pump hours: 123

       Crash bearings: 100%

Jeff K, Dave B, Oli P

All of the optics (except OFIS, OPOS, and HXDS) were originally built with a DACKILL that will only trip if all of that suspension's Watchdogs trip. This has resulted in some problems (74545, 74622). Because of this, there has been a push to update the logic for each suspension to have an OR instead of an AND, so that the IOP DACKILL trips as soon as any one of the stages trips.
The Watchdogs for these suspensions also rely on an outdated BLRMS to figure out if the stages are saturating, and people have been wanting this to be updated since 2017(FRS9392). This update to the watchdogs would remove the need for a USER DACKILL, so now is a perfect opportunity to do both at the same time! Suspension models created after 2019 (OFIS, OPOS, HXDS, and the new HXTS) were originally made with the updated watchdogs and without the USER DACKILL, and we haven't had any issues. The changes that we made line up with what was done for these previously changed models.
Today we updated the models for the ETMs and TMSs(76305), and we will gradually be updating all of the models.
Changes made:
QUAD MASTER and TMTS Master sus models (QUAD_MASTER.mdl, TMTS_MASTER.mdl):
    - Top level: Removed USER DACKILL and WD block output flags(attachment1)
    - Inside each block with watchdogs: removed the watchdog flags that connect the WD RMS to the DACKILL(attachment2)
    - Inside each WD block within stage blocks: swapped the old WD BLRMS block with the better BLRMSLP block(attachment3)
Individal sus models (h1susetmx.mdl, h1susetmy.mdl, h1sustmsx.mdl, h1sustmsy.mdl):
    - Removed top level WD_2_ISI output flags and connection of WD_2_ISI out to ISI model(attachment4)
Individual sus pi models(h1susetmxpi.mdl, h1susetmypi.mdl):
    - Found out during installation of these updated models that a WD value that we had removed in the individual models went out to the pi models. The sus pi models were updated to include constants as inputs in lieu of the removed WD values(attachment5)
ISI QUAD models (h1isietmx.mdl, h1isietmy.mdl):
    - Since the USER DACKILL connects to dolphin, we also changed the ISI QUAD inputs that feed into SUSWD_2_PAYLOAD from ground to both be 0 for WDMON_STATE_DOLPHIN and WDMON_STATE_DOLPHIN_ERR respectively(WDMON_STATE_DOLPHIN_ERR needs to be 1 because it later gets inverted)(attachment6)
Changes to medms (ETMs,TMSs adl files):
    - Removed the IOP DACKILL button on suspension medm and TO ISI arrow(attachment7)
    - Inside the watchdog subscreens: added in the filter banks for the low pass and removed the diagrams showing the USER DACKILL logic(attachment8).
All changes have been committed to svn.

No SQZ time taken this morning 15:29UTC to 15:51UTC. There was small glitches at 15:35:37 and 15:41:53. Best stretch of time is 15:42:00 to 15:51:00. Took no sqz time with hot OM2 in 74834 / 74640, Cold OM2 Dec 20th 18:00- 18:18UTC 74935.

Followed Naoki's 70642 instructions. Pushed to aligoNB git. There was a small EQ passing through just before I started this. Had ~3dB of constant SQZ.

Last ran and analyzes aligoNB injections with hot and cold OM2 in December 74943 / 74788. We haven't measured coupling of frequency and intensity noise since August 2023: 72140.

Fil, Dave:

I've updated the dewpoint.adl MEDM to show the decommissioning of HAM 4. Fil found yesterday that the Modular Container #2 sensor is misreading and will be replaced.

TITLE: 03/13 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: USEISM
    Wind: 4mph Gusts, 3mph 5min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.64 μm/s
QUICK SUMMARY: H1 has been locked for the past 6 hours, BNS range currently at 135Mpc.

• Wind is low, microseism is elevated
• EDC shows 12 disconnected chanlles all related to nuc28 (currently powered off as the monitors are being replaced)

Very low frequency angular lines are being injected in the OMC ASC controls starting at 14:39 UTC. The longer they run the better, but please feel free to stop them if other tests are ongoing.

awggui's are running on cdsws26.

This is a test to see if we can find a better OMC alignment position, and if this has any effect on DARM noise.

I was able to request and transition to the new DARM state without issue. ETMX still saw a pretty large kick. I'll have to circle back re: how large compared to previous attempts. We will also want to take a look at any effects moving the integrator on L2 LOCK L had.

Note: We do get a few SUS_PI warnings shortly after transitioning to this state.

Quiet time to monitor for non-stationarity:
Start GPS: 1394344327
Stop GPS: 1394346169

Turned off cal lines at GPS 1394346770.39

Elenna started a Bruco after the cal lines were turned off.  here is a screenshot of DARM in the new configuration. 20-90Hz looks high and below 15Hz looks low. It's hard to tell how much of this is real until CAL-CS is calibrated & that calibration is propagated to the DTT template.

I started an L2 LOCK IN1/IN2 injection using noise recorder at 1394347034.426. We used a tuned broadband measurement that Craig and I put together. Apparently it was too strong because we lost lock from this injection. It also tripped EX. I requested DOWN and the EX trip alarm reset. 

J. Kissel, L. Dartez

Jeff ran the calibration measurement suite. We processed it according to the instructions here. I then updated the CAL_DELTAL_EXTERNAL calibration using the new report at /ligo/groups/cal/H1/reports/20240311T214031Z.

Trent, Georgia

We wanted to see how the arm cavity higher order modes changed with squeezing phase, so we plotted Dhruva's data from 19 February 2023 zooming in on the appropirate frequency range. See Dhruva's post for more info about the data. We have two plots, one at higher frequency (10200Hz - 10900Hz) (02 20 modes) and one at lower frequency (5000Hz - 5700Hz) (01, 10 modes).

Note that for the high frequency plot, the y-arm HOM is degenerate with the acoustic modes of the test masses (at ~10.4kHz) and the acoustic modes dominate the signal at this frequency. Therefore, we can't say much about the squeeze angle dependance of the y-arm HOM but the x-arm HOM amplitude does not seem to change with the squeeze angle.

The low frequency plot also does not show a significant change in the HOM amplitude.

The list below gives the GPS times and the corresponding curve colors.

Ref 0: 1360822152 (Red)

Ref 1: 1360822844 (Blue)

Ref 2: 1360823864 (Green)

Ref 3: 1360824833 (Brown)

Ref 4: 1360825873 (Pink)

Ref 10: 1360834978 (Teal)

A nice DARM video is found in this post which shows the arm HOM shifting in frequency as the test masses thermalize.