Friday Final Ops Report.

TITLE: 09/04 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: Ibrahim
SHIFT SUMMARY:
Most of todays work was the VAC team Pumping down ETMX.
The clean room was turned off over at EX.

Keita has been working on the OMC. 

There was some SPI work done in the morning, unfortunately the afternoon SPI Ground loop work may have been distracted by finding Bruce Wayne (a Big Brown Bat) giving him self a tour around the LVEA, which was cut short when Jennie W found him flying around the pre-LVEA area like a "bat out of CER"!
Bruce has ditched his new personal tour guide and is still at large flying around inside the LVEA somewhere.
.... so LVEA is LASER Safe but BAT hazard....
Bat signal is on.

LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
15:21	VAC	Jordan	EX	N	Pumpiing Down ETMX	18:40
15:50	FAC	Kim	EX	N	Technical Cleaning & Resupply	17:59
20:26	VAC	Jordan	EX	N	Turning off clean room & checking Vac pumps.	21:13
21:36	SQZ	Sheila	FCES	N	Checking on Ham 8	23:55
21:46	SPI	Jennie W & Marc	LVEA	N	Checking cables for Ground Loops for SPI	23:55
22:00	VAC	Jordan	EX	N	Turning on ion pumps.	22:33
22:33	Safety	Bruce Wayne	CER-ish	N	Bruce is flying about eating bugs in the CER/ pre-LVEA area.	04:33
23:21	VAC	Jordan	EX	N	Checking VAC Status	23:38

 

TF of ETMX after Vacuum reached 1*e-7 Torr

Transfer functions  were taken again of ETMX after the VAC team took some air out of the chambers for us.
Measurements were taken on H1SUSETMX_M0 and R0.

Continued EX Pumpdown

This morning I continued pumpdown of EX after the TMDS exercise yesterday, using the two mobile ISP1000 scroll pumps. 

Starting Pressure: 5.35 Torr	Start Time: 8:32 am
Turbo Crossover Pressure: 500 mtorr	Turbo On: 10:52 am
Ion Pump Opening Pressure: 1.1E-7 Torr	Ion Pump On: 3:12 pm

The turbo reached full speed in ~30 minutes and I transitioned the backing pumps from the ISP1000s to the single ISP250 on the turbo stand once the turbo inlet pressure was <1E-5 Torr.

The cooling water was adjusted on the turbopump stand so that the pump and controller pressures were <= 40C.

The chamber pressure quickly reached low E-7 Torr range, so I opened up the ion pump (IP12) to assist with high vacuum pumping.

I also turned off the EX cleanrooms at Sheila's request at ~1:35pm.

We will still need to leak check the small 2.75" CF blank we installed where the TMDS ionizer attaches before we can open up GV20. EX volume will pump with both turbopump and ion pump over the long weekend.

Bat flying round LVEA entrance hall

Marc, Jennie, Tyler,

 

Marc and I discovered a little bat friend, Bruce, flying around the space between the roll-up doors just after the LVEA entrance. After consulting with FAC this bat is up too high to catch so we will monitor the situation and try and remove him Monday.

Compensation for errors in the CPS whiteing filters for HAM3

NOTE - There is a bunch of discussion about the meausrements and compensation for the whiteing filters for the CPSs in SEI log 2590 and comments.
I did a fit to Jim's measurements for HAM3, here are the strings to paste into foton:

ch H1: zpk([0.1447;1.6372], [0.14885;1.5916], 1, "n")
ch H2: zpk([0.1447;1.6311], [0.14829;1.5916], 1, "n")
ch H3: zpk([0.1447;1.6219], [0.14746;1.5916], 1, "n")
ch V1: zpk([0.1447;1.6422], [0.1493;1.5916], 1, "n")
ch V2: zpk([0.1447;1.6268], [0.1479;1.5916], 1, "n")
ch V3: zpk([0.1447;1.6334], [0.1485;1.5916], 1, "n")

Jim - Can you please add these foton design strings to module 2 of the H1:ISI-HAM3_CPSINF_ch banks?
These cancel the p/z pair in the first module and replace it with a pair in a slightly different place. Like the other symmetrization filters, we then run FM1 and FM2. 
This is a little wonky, but I think it makes it easier to keep track of what is going on down the road.
I would suggest a name like sym_v1 for the module, but feel free to pick a better one. You should be able to copy/ paste this text into the command box in the foton file. 
If this works, we can think about some better automation. 

I've attached 2 images (more in SEI log). First is the TFs Jim measured (after correcting for the DAQ filters and an 800 microsec time delay (what is that?!)), normalized by the expected TFs. The little bellies are consistent with errors in the 10 microfarad cap (This is pretty good, honestly, for that kind of a part). The second image shows the data for V1 and fit for V1, so you can see the fit is pretty good.

SPI P and Y Signals, Now Calibrated with QPDA Dark Noise Fixed

J. Kissel, J. Wright

Jennie and Marc did some dark noise investigations yesterday afternoon, found grounding issues, but then reverted the temporary configuration that improved the situation. 
However, this morning, mis-reading their aLOG thinking that the solution was still in place, I re-took new ASDs excited to see QPDA fixed.
Even though their temporary solution has been reverted, QPDA still seems to be fixed. 

So -- here's some excellent, final answer plots for pitch and yaw, comparing HAM2 and HAM3 rotation against their local sensors.

PITCH
    - Now, as expected, the whitened ADC noise QPDA aka ISIK's HAM3 sensor is the factor of ~5x larger where the QPD is limited by ADC noise above 0.5 Hz, and it has the same inverse-whitening-filter shape as QPDB.
    - Encouragingly, the QPDA ISIK optical lever PIT signal matches the HAM3 CRS RY signal below 0.5 Hz -- so this QPD will be at least a little bit useful!
    - The noise floor of the QPDA ISIK optical lever PIT signal is better than the CRS above ~2 Hz, though the actual platform motion (as reported by the GS13s) is still much lower than that.

    Very interesting science -- 
    - The improvement in platform motion of HAM3 from blending in the CRS is corroborated with the ISIK optical lever signal below 0.5 Hz.
    - The QPDB measure of HAM2 shows that there's a lot more physical motion in PIT in the 1 to 10 Hz region than is reported by the in-loop GS13s. In that region, the QPD's signal is a factor of 10 above the noise floor, so I'm pretty sure this is real signal.

YAW 
    - Again, the two SPI QPDs noise floor now makes sense, with the QPDB (on HAM3) measurement of HAM2 (ISIJ) noise floor being a factor of ~5x better than the QPDA (on HAM2) measurement of HAM3 (ISIK).
    - Thus, the SPI OL YAW measure of HAM2 agrees with the local HAM2 sensors up to ~0.8 Hz, but the OL YAW measure of HAM3 only agrees up to 0.5 Hz.


Measurement time: 2026-09-04 16:47 UTC. I took 25 averages with a 0.01 Hz frequency resolution. Hanning window with 50% overlap.

ISIs were isolated, IMC was locked, still no IFO tho. sensor correction was ON in the nominal WINDY configuration. No earthquakes. CRS is blended in with ISI HAM3.
Spots centered, nominal sum voltage.

DTT Calibration of traces beyond what's done in the front-end is what's quoted in LHO:91809, namely -- just a conversion of nanoradians to radians for sensors already in displacement, and converting the GS13s from inertial sensor units asymptoting to 1 [nm/s] into displacement by inverting the ideal 1 Hz pendulum response. 

Using Vibration Sensors To Gauge Health Of HVAC Fans.

Famis 79936 Using Vibration Sensors To Gauge Health Of HVAC Fans.
At around 6:07 UTC there was a blip across multiple HVAC fans.  
It happened on both the CS fans, and the Out building fans. 

Taking a closer look it seems as if they all turned off for some reason and came back online, some taking longer than others.
 

 

DTT Calibration Parameters for ISI Signals Relevant to SPI L, P, and Y

J. Kissel

Channels already in longitudinal or translation displacement units (in this case IFO X or suspension point longitudinal)
    H1:ISI-HAM2_BLND_CPSX_IN1_DQ      HAM2 X displacement, capacitive position sensor, pre-blend
    H1:ISI-HAM3_BLND_CPSX_IN1_DQ      HAM3 X displacement, capacitive position sensor, pre-blend

    H1:ISI-HAM2_ISO_X_IN1_DQ          HAM2 X displacement, post-blend combined sum on CPS and GS13, feedback loop error signal, contains feedback loop suppression
    H1:ISI-HAM3_ISO_X_IN1_DQ          HAM3 X displacement, post-blend combined sum on CPS and GS13, feedback loop error signal, contains feedback loop suppression

    H1:ISI-DIFF_H2_BLND_SS_X_DQ       HAM2 X displacement, post-blend combined sum of CPS and GS13, out-of-loop
    H1:ISI-DIFF_H3_BLND_SS_X_DQ       HAM3 X displacement, post-blend combined sum of CPS and GS13, out-of-loop

    H1:ISI-HAM2_ISO_X_EXC             HAM2 X excitation, in same units as ISO_X_IN1_DQ error signal, and thus displacement (rather than the usual "counts")
    H1:ISI-HAM3_ISO_X_EXC             HAM3 X excitation, in same units as ISO_X_IN1_DQ error signal, and thus displacement (rather than the usual "counts")

    H1:HAM2-SUSPOINT_MC1_EUL_L_DQ     HAM2 GS13s projected for MC1 suspension point and calibrated into L displacement (linear combo of X, Y, RX, RY, and RZ)
    H1:HAM2-SUSPOINT_MC3_EUL_L_DQ     HAM2 GS13s projected for MC3 suspension point and calibrated into L displacement (linear combo of X, Y, RX, RY, and RZ)
    H1:HAM2-SUSPOINT_PRM_EUL_L_DQ     HAM2 GS13s projected for PRM suspension point and calibrated into L displacement (almost entirely X, RY, and some RZ)
    H1:HAM2-SUSPOINT_PR3_EUL_L_DQ     HAM2 GS13s projected for PR3 suspension point and calibrated into L displacement (almost entirely X, RY, and a little RZ)
    H1:HAM3-SUSPOINT_MC2_EUL_L_DQ     HAM2 GS13s projected for MC2 suspension point and calibrated into L displacement (almost entirely X, RY, and some RZ)
    H1:HAM3-SUSPOINT_PR2_EUL_L_DQ     HAM2 GS13s projected for PR2 suspension point and calibrated into L displacement (almost entirely X, RY, and some RZ)

    H1:ISI-DIFF_H23_SS_X_OUT_DQ       (HAM3 - HAM2) differential displacement (one-way distance between H3 and H2)

    H1:SPI-H23_DIFFDISP_MAIN_OUT_DQ   (HAM3 - HAM2) differential displacement (has been converted into one-way distance between H3 and H2)

    To convert to [m] of displacement from these channels which have front-end calibrated units of [nm]:
        DTT Units: [m]
        DTT Calibration: 
            - Gain :: 1e-9 [m/nm]
            - {z:p} :: {(none),(none)}

Channels already in rotational displacement units (in this case IFO RY or RZ or suspension point PIT or YAW)
    PITCH / RY
        H1:ISI-HAM2_BLND_CPSRY_IN1_DQ      HAM2 RY displacement, capacitive position sensor, pre-blend
        H1:ISI-HAM3_BLND_CPSRY_IN1_DQ      HAM3 RY displacement, capacitive position sensor, pre-blend

        H1:ISI-HAM3_BLND_CRSRY_IN1_DQ      HAM3 RY displacement, cylindrical rotation sensor, pre-blend (HAM3 only)

        H1:ISI-DIFF_H2_BLND_SS_RY_DQ       HAM2 RY displacement, post-blend combined sum of CPS and GS13, out-of-loop
        H1:ISI-DIFF_H3_BLND_SS_RY_DQ       HAM3 RY displacement, post-blend combined sum of CPS and GS13, out-of-loop

        H1:ISI-HAM2_ISO_RY_IN1_DQ          HAM2 RY displacement, post-blend combined sum on CPS and GS13, feedback loop error signal, contains feedback loop suppression
        H1:ISI-HAM3_ISO_RY_IN1_DQ          HAM3 RY displacement, post-blend combined sum on CPS and GS13, feedback loop error signal, contains feedback loop suppression

        H1:ISI-HAM2_ISO_RY_EXC             HAM2 RY excitation, in same units as ISO_RY_IN1_DQ error signal, and thus displacement (rather than the usual "counts")
        H1:ISI-HAM3_ISO_RY_EXC             HAM3 RY excitation, in same units as ISO_RY_IN1_DQ error signal, and thus displacement (rather than the usual "counts")

        H1:HAM2-SUSPOINT_MC1_EUL_P_DQ     HAM2 GS13s projected for MC1 suspension point and calibrated into P displacement (linear combination of IFO RX and RY)
        H1:HAM2-SUSPOINT_MC3_EUL_P_DQ     HAM2 GS13s projected for MC3 suspension point and calibrated into P displacement (linear combination of IFO RX and RY)
        H1:HAM2-SUSPOINT_PRM_EUL_P_DQ     HAM2 GS13s projected for PRM suspension point and calibrated into P displacement (almost entirely RY)
        H1:HAM2-SUSPOINT_PR3_EUL_P_DQ     HAM2 GS13s projected for PR3 suspension point and calibrated into P displacement (almost entirely RY)
        H1:HAM3-SUSPOINT_MC2_EUL_P_DQ     HAM2 GS13s projected for MC2 suspension point and calibrated into P displacement (almost entirely RY)
        H1:HAM3-SUSPOINT_PR2_EUL_P_DQ     HAM2 GS13s projected for PR2 suspension point and calibrated into P displacement (almost entirely RY)

        H1:SPI-H23_OL_ISI_J_PIT_OUT_DQ    HAM2 PIT rotation
        H1:SPI-H23_OL_ISI_K_PIT_OUT_DQ    HAM3 PIT rotation

    YAW / RZ
        H1:ISI-HAM2_BLND_CPSRZ_IN1_DQ      HAM2 RY displacement, capacitive position sensor, pre-blend
        H1:ISI-HAM3_BLND_CPSRZ_IN1_DQ      HAM3 RY displacement, capacitive position sensor, pre-blend

        H1:ISI-DIFF_H2_BLND_SS_RZ_DQ       HAM2 RY displacement, post-blend combined sum of CPS and GS13, out-of-loop
        H1:ISI-DIFF_H3_BLND_SS_RZ_DQ       HAM3 RY displacement, post-blend combined sum of CPS and GS13, out-of-loop

        H1:ISI-HAM2_ISO_RZ_IN1_DQ          HAM2 RY displacement, post-blend combined sum on CPS and GS13, feedback loop error signal, contains feedback loop suppression
        H1:ISI-HAM3_ISO_RZ_IN1_DQ          HAM3 RY displacement, post-blend combined sum on CPS and GS13, feedback loop error signal, contains feedback loop suppression

        H1:ISI-HAM2_ISO_RZ_EXC             HAM2 RY excitation, in same units as ISO_RY_IN1_DQ error signal, and thus displacement (rather than the usual "counts")
        H1:ISI-HAM3_ISO_RZ_EXC             HAM3 RY excitation, in same units as ISO_RY_IN1_DQ error signal, and thus displacement (rather than the usual "counts")

        H1:HAM2-SUSPOINT_MC1_EUL_Y_DQ     HAM2 GS13s projected for MC1 suspension point and calibrated into P displacement (linear combination of IFO RX and RY)
        H1:HAM2-SUSPOINT_MC3_EUL_Y_DQ     HAM2 GS13s projected for MC3 suspension point and calibrated into P displacement (linear combination of IFO RX and RY)
        H1:HAM2-SUSPOINT_PRM_EUL_Y_DQ     HAM2 GS13s projected for PRM suspension point and calibrated into P displacement (almost entirely RY)
        H1:HAM2-SUSPOINT_PR3_EUL_Y_DQ     HAM2 GS13s projected for PR3 suspension point and calibrated into P displacement (almost entirely RY)
        H1:HAM3-SUSPOINT_MC2_EUL_Y_DQ     HAM2 GS13s projected for MC2 suspension point and calibrated into P displacement (almost entirely RY)
        H1:HAM3-SUSPOINT_PR2_EUL_Y_DQ     HAM2 GS13s projected for PR2 suspension point and calibrated into P displacement (almost entirely RY)

        H1:SPI-H23_OL_ISI_J_YAW_OUT_DQ    HAM2 PIT rotation
        H1:SPI-H23_OL_ISI_K_YAW_OUT_DQ    HAM3 PIT rotation

    To convert to [rad] of rotational displacement from these channels which have front-end calibrated units of [nrad]:
        DTT Units: [rad]
        DTT Calibration: 
            - Gain :: 1e-9 [rad/nrad]
            - {z:p} :: {(none),(none)}


Inertial sensor channels in translational velocity units, that need more than just a scale factor:
    X Translation Displacement
       H1:ISI-HAM2_BLND_GS13X_IN1_DQ      HAM2 X displacement, GS13 inertial sensor, pre-blend
       H1:ISI-HAM3_BLND_GS13X_IN1_DQ      HAM3 X displacement, GS13 inertial sensor, pre-blend

    To convert to [m] of translational displacement from these channels which have front-end calibrated units of "inertial sensor response, which asymptotes to 1 [nm/s]":
        DTT Units: [m]
        DTT Calibration: 
            - Gain :: 1e-9 [(m/s)/(nm/s)]
            - {z:p} :: {(0.707 0.707),(0 , 0)} (note the space separation for the zeros -- representing a complex pair of zeros at 1 Hz, 45 [deg] apart -- and the comma separation for the poles.)

        Important :: In the UNITS tab of the plot display, chose "rad/Hz^{1/2}" which integrates from velocity into displacement. This needs to be checked/done frequency as DTT resets the units every time you remeasure or make a change to the plots.


Inertial sensor channels in rotational velocity units, that need more than just a scale factor:

    RY Rotation Displacement
       H1:ISI-HAM2_BLND_GS13RY_IN1_DQ      HAM2 RY displacement, GS13 inertial sensor, pre-blend
       H1:ISI-HAM3_BLND_GS13RY_IN1_DQ      HAM3 RY displacement, GS13 inertial sensor, pre-blend
    
    RZ Rotation Displacement
       H1:ISI-HAM2_BLND_GS13RZ_IN1_DQ      HAM2 RY displacement, GS13 inertial sensor, pre-blend
       H1:ISI-HAM3_BLND_GS13RZ_IN1_DQ      HAM3 RY displacement, GS13 inertial sensor, pre-blend

    To convert to [rad] of rotational displacement from these channels which have front-end calibrated units "inertial sensor response, which asymptotes to 1 [nrad/s]":
        DTT Units: [rad]
        DTT Calibration: 
            - Gain :: 1e-9 [(rad/s)/(rad/s)]
            - {z:p} :: {(0.707 0.707),(0 , 0)} (note the space separation for the zeros -- representing a complex pair of zeros at 1 Hz, 45 [deg] apart -- and the comma separation for the poles.)

        Important :: In the UNITS tab of the plot display, chose "rad/Hz^{1/2}" which integrates from velocity into displacement. This needs to be checked/done frequency as DTT resets the units every time you remeasure or make a change to the plots.

Note, you could do the integration in the calibration interface (rather than forcing DTT to do it) by adding a third pole at 0 Hz in the {z:p} list, and changing the Gain to 1e-9/(2*pi) = 1.59e-10.

Calibration of JAC error signal into m

I wanted to get a rough number for the JAC error signal in Hz, this it to allow Jeff and I to measure the frequency noise of the JAC as an independent monitor of the IMC frequency noise which will allow us to compare the IMC length noise to the SPI length noise.

I think Masayuki calculated this back in March LHO alog #89399  but I wanted to recheck it as the Guardian settings have been changed since then.

I measured the unlocked error signal Vpp at H1:JAC-L_SERVO_IN1_DQ to be 1.01365V.

The value in metres is the half-width at half-maximum of the cavity.

First calculate the HWHM in Hz:

HWHM = FSR/2*Finesse  = 0.595 MHz.

The finesse was measured by Masdayuki and I at Caltech for our JAC which is unit 008 (see E2500324).

The FSR of the JAC I got from T0900616 to be 148.5MHz (couldn't find the exact FSR for this specific unit mentioned anywhere so used the one quoted in the PMC design document).

This means to measure the frequency noise we need to multiply the signal at 

H1:JAC-L_SERVO_IN1_DQ by 0.587 e6Hz/V to measure frequency noise.

 

PRMI+ DRMI locking

Summary:  PRMI and DRMI and locking with reasonable stability.  BS top mass damping rings more than we'd like, and it seems like we should swtich out oplev damping for M3 wit damping. 

• Aligned PRMI adjusting BS and by hand in MICH dark, PRM by hand with PRX. This gives PRMI flashes up to 60 counts on POPAIR 18 I DQ
• there was a bug in the guardian that meant oplev damping wasn't actually coming on for PRMI acquisition, I fixed this and added a line to turn it off after PRMI locked. 
• PRMI is stably locked
• DRMI locked easily on the first try, when optical lever damping was not on.  The build ups were semi stable, the main fluctuation seemed to be correlated with BS M3 pit. THen I could not lock DRMI with the optical lever damping on for 10 minutes, and it relocked once I turned oplev damping off.  
• Looked at a time series of the optical lever and M3 wits while PRMI was trying to acquire.  It seems that M3 Wits have a better SNR than the optical lever for the motion when trying to acquire.  
• I moved the BS sliders by 10 urad in pitch and yaw.  Screenshot attached. 
  • The step response has significant ringing in at 0.4 Hz, where the overshoot is about half the step size.  We should be able to improve this with the top mass damping.   
  • The optical lever is badly cross coupled, as has been noted before.  
  • Based on the table below I applied a calibration of 6.4 to oplev pit and 4 to oplev yaw to match the optical lever steps to the M3 wit steps in my dtt template.  The pitch spectra comparison shows that M3 wit agrees with the optical lever, but has better SNR.  The yaw optical lever shows significantly more motion than M3 wit, but this is probably from the cross coupled pitch signal (see coherences).  

slider	10 urad P	10 urad Y
M1 damp in1	9 urad P (no Y step, but ringing)	5.5 urad Y (P only ringing 1.8urad P-p)
M3 WIT	2.4 urad P (no Y step, but ringing 0.2urad pp)	9.3 urad Y (P only ringing 8urad pp)
M3 oplev	0.37 urad P (0.95urad Y)	2.3 urad Y (step of 0.9 in Y, ringing 0.37 urad pp)

• DRMI locking was stable for 10 minutes, it took a few minutes to relock after the lockloss.  I'm stopping DRMI work for now so Keita can do his test. 

Unshuttered SPI, Reset Phase Unwrapping Algo, Restored QPDA SEG OFFSETS (Recovery from DARK NOISE configuration)

J. Kissel

Jennie had shuttered the SPI yesterday as a part of further QPDA dark noise (LHO:91791). I 
    - unshuttered it this morning, 
    - restored the dark offsets in the QPDA SEG banks (rather than the fake signal offsets) and 
    - reset the phase unwrapping algorithm in the IFO signal chain. 
Power monitoring came back to (MEAS, REF) = (13.6,10.4) [V], which (from memory) is typical.
QPD centering came back to (QPDA; SUM, P, Y -- QPDB; SUM, P, Y) = (25.3 , 0.014 , 0.020 ; 30.0 , -0.016, -0.017)

Restoration complete by 2026-09-04 16:08:00 UTC.

z avg 10 H1:SPI-H23_FBR_PWRIN_MEAS_OUT_DQ H1:SPI-H23_FBR_PWRIN_REF_OUT_DQ H1:SPI-H23_OL_QPD_A_SUM_OUT_DQ H1:SPI-H23_OL_QPD_A_PIT_OUT_DQ H1:SPI-H23_OL_QPD_A_YAW_OUT_DQ H1:SPI-H23_OL_QPD_B_SUM_OUT_DQ H1:SPI-H23_OL_QPD_B_PIT_OUT_DQ H1:SPI-H23_OL_QPD_B_YAW_OUT_DQ
H1:SPI-H23_FBR_PWRIN_MEAS_OUT_DQ 13.648861408233643
H1:SPI-H23_FBR_PWRIN_REF_OUT_DQ 10.352759647369385

H1:SPI-H23_OL_QPD_A_SUM_OUT_DQ 25.805402565002442
H1:SPI-H23_OL_QPD_A_PIT_OUT_DQ 0.014341713674366475
H1:SPI-H23_OL_QPD_A_YAW_OUT_DQ 0.019697268679738044

H1:SPI-H23_OL_QPD_B_SUM_OUT_DQ 30.1885705947876
H1:SPI-H23_OL_QPD_B_PIT_OUT_DQ -0.013530098926275968
H1:SPI-H23_OL_QPD_B_YAW_OUT_DQ -0.018152973800897598

Friday Morning Ops Report.

TITLE: 09/04 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 6mph Gusts, 2mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.14 μm/s 
QUICK SUMMARY:

Vacuum system has held steady over night but sensors suggesting that there is more pump down to do at EX.
More transfer functions will be ran on the SUS ETMX.
 

 

Vacuum Recovery From TMDS Work at X-End

(Jordan V., Richard M., Gerardo M.)

After the second discharge at BSC9, we removed the ionizer from the injection port and installed a 2.75" CF blank on its place.  We started the pumpdown, and after a few minutes we dumped the dead volume between the tiny injection gate valve and the blank into the main volume.  We used the two ISP-1000 to start the rough down, but stopped at 5:50 pm local time for the night, vacuum pressure is at 5.35 Torr, pumpdown will restart tomorrow.

During both discharges, noted here, we encountered some minor issues that were dealt with on the fly.

• The failure of the X-End ionizer, we "borrowed" the ionizer from Y-End.
• The tiny gate valve at the injection port at BSC9 -Y door does not appear to be healthy (photo to be attached later by Jordan).  We'll need to replace the tiny valve on the next vent.
• Another issue we encountered was the ISP-1000 twins with the wrong rotation, and by serendipity Richard showed up to correct the rotation issue on both scroll pumps.
• The pipe for the delivery of the purge air to the TMDS gas delivery system (TMDS table), had a bunch of leaks (still has some little ones) and some cross threaded components (these were replaced), but not all leaks were addressed.

PRMI summary from today

[Louis, Sheila, TJ, Camilla]

This is a continuation of the effort to recover PRMI.

• This morning I reset IM4, PRM, PR2, and PR3 back to their slider positions just before the x-arm gate valve was closed. 
• I aligned ITMX then ran ALIGN_IFO::PREP_FOR_MICH. Normally this would have been fine but I'd missed that Oli was in the process of setting up health check measurements on ETMX. PREP_FOR_MICH moved the ETMX suspension and moved it out of the HEALTH CHECK state, which Oli needed it in for their tests.

• Sheila edited ISC_LIBRARY.py to have set_sus_config() refrain from messing with the ETM suspensions when the flag lscparams.gate_valve_flag is True. She also updated ISC_DRMI::PREP_PRMI to set relaxed trigger thresholds for MICH when the gate valves are closed (via the same flag).

• I moved us directly to ALIGN_IFO::MICH_DARK_LOCKED and adjusted the BS. The sliders were left at P:-738, Y:338.31.

• We went to PRX and touched up the PRM. Sliders were left at P:-1181.3, Y:-451.4.

• From here we tried going to PRMI. We noticed that our triggers were very brief so I moved PRM further to maximize POPAIR. From here sliders were moved to P:-1182.3 Y:-432.4. Also while trying to acquire PRMI we noted that the beam spot on the AS AIR camera was showing a lot of motion. My initial suspicion was that it was the BS (for some reason). 

• I modified ISC_DRMI::ACQUIRE_PRMI to turn on the oplev damping on the BS. We've been doing this often when locking PRMI to help with BS motion (see 91612). The usual prescription is to turn off the oplev damping once PRMI is locked. I have not codified this in the guardian yet.

Since there was so much unexplained motion today during our attempts, I decided to take a look at the error signals and compare them to a previous PRMI lock stretch that was able to hold for much longer. I chose as reference 1471973449 (August 28 17:30 UTC) and compared it against one of our attempts today at 1472510961 (September 3 22:49 UTC). The error signals spectra for MICH and PRCL showed a lot of motion between 8 and 20 Hz. Ibrahim noted that an earthquake was rolling through around the same time. But the earthquake came through roughly an hour before this locking attempt and the ISI was back in nominal state by this time so I don't think the two are related. A comparison of the time series today and at the reference time also suggest that we may not be fully aligned onto the diodes in HAM1 and ISCT1. We might consider making sure that we're properly aligned on all the relevant diodes next week. I don't think we've taken a close look at that since pico'ing in HAM3 (91789). 

 

 

DAQ DC ethernet stats are being dumped to help search for cause of CRC errors

h1daqdc0 and h1daqdc1 "ethtool -S" stats are being dumped hourly for the DAQ lan interface. Purpose is to gather evidence for the cause of somewhat rare CRC errors (really dropped data blocks) from the real-time system DAQ streams.

Location of the files is /opt/rtcds/userapps/release/cds/common/scripts/daq_eth_stats/archive

The stats gathering services are named daq_eth_stats and are hand-written systemd service and timer units on both systems.

BSC10 Annulus Ion Pump Railed

The annulus ion pump for BSC10 railed late last night, around 8:50 pm local time.
Nothing to do for now, but soon we will check the annulus ion pump to see what is wrong with it.

SPI L Wrapped Phase Excursions on 2026-08-26 @ 17:16 UTC -- Probably Excitation

J. Kissel

I found the SPI L MEAS and REF IFO signals -- namely in its unwrapped phase signal form -- off in the weeds this morning at ~1700 [rad] and ~1000 [rad], indicating that the phase unwrapping algorithm needs to be reset.

I'm probably just gathering statistics here rather than identifying a cause, but since the system is still new, I figure calling out *when* and "what else was going on?" the SPI longitudinal (L) phase signal shows events in which the unwrapping algorithm glitches or drifts off into the weeds is worth it. There were two back-to-back phase excursions on Wednesday 2026-08-26 17:16 and 17:17 UTC (10:16a and 10:17a local PDT). 

Here're a few trends of *some* channels that I thought might be the obvious culprits -- 
    (1) Did the HAM2 or HAM3 (H23) ISIs trip? No.
    (2) Was there large excess motion or glitches in the H23 ISIs? No. (Only X is shown, but I checked Y, Z, RX, RY, and RZ and they also don't show anything)
    (3) Did the SPI's optical levers see anything? Yes, but not excellently correlated.
    (4) Was there main IFO laser light scattered from within the chamber into the SPI? Doubtful. While the IMC was struggling to lock, locking events (i.e. flashes on MC2 TRANS) are not obviously correlated.

I only show the MEAS_A raw phase signal (first row), but the trend of the unwrapped phase shows you that all PDs saw these glitches.

Zooming out, look at the second trends, the phase signal shows that it was "buzzing" at a max and min of -2*pi and +2*pi through out a time from 17:11:32 UTC to 17:17:44 UTC -- which looks very suspiciously like some excitation.
BUT -- the phase excursion doesn't happen until ~80% of the way through whatever excitation this is...

As of this morning -- There haven't been any unwrapped phase excursions since this one.

I've reset the phase unwrapping algorithm on 2026-08-31 16:43 UTC but hitting the H1:SPI-H23_IFO_PHASE_UNWRAP_RESET button, available to hit on each of the MEAS_IFO and REF_IFO CONDITIONING screens, linked from the SPI OVERVIEW.