WP 13259
ECR E2200043

The CS HEPI system is planned to be upgraded to a Beckhoff PLC system. Modifications to the motor control panels to readout the VRD readback signal completed. Cabling and panel connections cleaned up. Part of ECR E2200043.

Prior to starting work:

1. All pump stations were locally powered off via the front panel OFF button
2. Breakers to pump stations powered off
3. An anti-static floor mat and a grounding wrist strap used when working on the control panels

[Shoshana, Ryan S]

Yesterday we began building the second set of CRSs sent over from LLO (mostly just putting in heli-coils). I (Shohana) will probably continue working on them today

For some of the parts sent over from LLO (where they had already gone through clean and bake) we found some black residue in some of the aluminum foil wrappings and on the parts (specifically the cross beams [D2300102] and the solid supports [D2300144]) some of which would come off when wiped, but some of the residue would not. Pictures below

J. Kissel
E2600106 / IIET:37433
D2400107-v4

I've decommissioned the SPI pathfinder's ISIK Transceiver as it stands now (D2400107-v4) by 
    - disconnecting all electronics cabling; PDs at the cable-table bracket and picomotors' quadrupus at each pico-actuated optic
    - disconnecting optic fibers
    - untangling the in-vac cabling and fibers, ensuring the
    - installing installation handles (LHO:90223)
    - setting up a new set of 1"D x 6"L class-B posts then
    - removed the 3x temporary class-B bolts and washers that had secured the breadboard to the posts
    - lifting and transferring the D2400107-v4 assembly over to the other position and
    - securing there with the 3x temporary class B bolts.

Pictures of the move attached.

J. Kissel, J. Warner
ECR: E2400026
WPs: 13237, LHO:13238
Final Design Doc: T2400145
Relevant Systems Level Drawings:
    . Mechanical Assemblies
        :: ISIJ Reflector D2400102
        :: HAM Table Baffles D1700335
        :: HAM2 Systems Layout D0901083 (not yet-inclusive-of-SPI)
    . Electronics Wiring Diagram 
    . Cable Routing In-vac Cable Routing Plan from G2401479 (pages )
    . Flange Layout D1002873-v11

Executive summary:
    - Removed ISIJ +X-side, center, HAM2 ISI table baffle from D1700265-v4 Type 2 
        :: Bracket mounting bolts left screwed into ISI optical table for this will eventually become a D1700265-v4 Type 3 and remounted.
    - Installed ISIJ Reflector + QPD Assembly D2400102 on +X ISI side wall (D071057-v2), with its shroud (D2500030) in place
        :: We didn't weigh it, but the SW Assembly predicts a mass of 1.96 [kg], which we can likely round up to 2.0 [kg] with the shroud installed.
    - Routed and connected QPD read-out cable system to D3 flange, F10 spigot.
    - Routed and connected picomotor cable system to existing D1101515 quadrupus leg Cable #3, J4 
        :: Cable #4, J5 is connected to IO PM5 mirror, Cables #2 J3 and #1 J2 were reset in neat coil with connectors floating to avoid electrical grounding as before.
    - Nudged make-shift baffle system using D1700261 ballast mass baffle mounted vertically on the +X / +Y / Beam Height corner of the chamber wall upon entry into beamtube.
        :: the will DEFINITELY need a technically-minded reset.

In at 10:30a PT and out by 12:30a PT. It's so lovely when everything goes to plan!

Pictures and further info to follow in the comments below.

WP 13216
ECR E1400386

Cables for the STS-2 signal distribution removed. Part of ECR E1400386. The STS-2 interface chassis were left powered off. Part of WP 13149.

As of 20:05 UTC, the cartridge from BSC2 (including the soon-to-be-decommissioned beamsplitter) has been placed on the test stand in the LVEA West bay. The cartridge was first lifted at 19:15 UTC before making its slow procession across the LVEA via the 5-ton overhead crane. More details and documentation to be posted later.

J. Kissel

After the install of front-end software (LHO:89777 and LHO:89919) the next step for SPI is MEDM screens -- the UI/UX for the SPI L interferometers and PY one-way optical levers.

Here, I post screenshots and corresponding userapps svn file and location.
Sub-screens and their future purpose will come in the comments, but make sure to also check out G2402138.

In the main entry, I show off the new place that SPI lives on the LHO sitemap and the overview screen.
The overview screen, and all subordinate screens use a marco file, which I also attach.

All of these files are, of course, properly version controlled in the userapps SVN, here:
OVERVIEW SCREEN
    ${USERAPPS}/spi/common/medm/
        SPI_CUST_OVERVIEW.adl        rev 35102

MACRO FILE
    ${USERAPPS}/spi/h1/medm/
        h1spih23_overview_macro.txt  rev 35106

J. Kissel, M. Pirello, B. Weaver

Betsy let us know that she's ready to start disconnecting cables of the ISIBS (the ISI supporting the Beam Splitter) in BSC2. As such, we used D0901301 to guide us, we turned off all three corners of the BSC ISI and T240 Interface Chassis in SEI-C5 U40-38 and U21-19 in the CER. The BSC ISI Interface Chassis are for the on-board capacitive position sensors (both stage 1 and stage 2 CPS), "high" frequency inertial sensors (stage 1 L4Cs and stage 2 GS13s), and the T240 Interface Chassis are for the on-board "low" frequency inertial sensors (stage 1 T240s).

All sensors are OFF as of 1:52p PT (2026-04-23 20:52 UTC).

J. Oberling, R. Crouch, J. Warner, B. Weaver, I. Abouelfettouh

This week we surveyed the position of the components that reside in WBSC2: The BS SUS cage (BSS), the ISI optics table (ISI Stage 2), and the 2 ITM Elliptical Baffles.

BS and the SUS Cage

The first picture shows our FARO survey of points on the BS SUS cage, chiefly along the bottom of the main support structure.  These were surveyed by holding the FARO SMR against the hole being measured; the PolyWorks software handles the compensation from the center of the SMR to the point being measured.  As can be seen, each point is very close in both X and Y axis position, being less than 0.1mm from its nominal location.  The Z axis deviations are larger, but the largest of them is just over 0.25 mm, so every point is well within the positioning specifications used during installation and alignment in 2013.

Line 1 in the picture was created from the first and last survey points and represents the pointing of the BS SUS cage; all angles are reported in degrees.  Some things to note here: I'm using the Acute Angle datum in PolyWorks, which is the angle measured from the closest axis.  For the HR surface normal of the BS, the X Acute Angle is measured from the -X axis, the Y Acute Angle is measured from the +Y axis, and the Z Acute Angle is measured from the +Z axis.  Since Line 1 is roughly perpendicular to the surface normal of the BS HR face, the axes the angles measure from are changed: The X Acute angle is now measured from the +X axis, the Y Acute Angle is still from the +Y axis, and the Z Acute Angle is now from the -Z axis.  In addition, since Line 1 is nominally perpendicular to the BS HR surface normal I would expect the X and Y Acute angles to be swapped (BS X Acute = Line 1 Y Acute; BS Y Acute = Line 1 X Acute), but they aren't exactly.  This appears to be a small error in the CAD model, if we make the assumption that the BS HR surface and the HR side of the BS SUS cage are nominally pointing in the same direction.  This does, however, change the deviations for the X and Y Acute angles for Line 1.  The table below shows what the data for Line 1 should be:

This means the BS SUS cage is yawed 0.0626°, or ~1.09 mrad, in the clockwise (CW) direction when looking from the top down (since Line 1 is closer to the +X axis than it should be).  The Z Acute Angle represents a slight counterclockwise (CCW) roll of the SUS cage, when looking directly at the HR surface of the BS.

To attempt to better locate the BS in the IFO coordinate system, several measurements were taken with a ruler from points on the "Figure 8" section of the BS SUS cage to the BS optic itself.  All measurments except one were done using a scale with 0.5 mm tic marks (so accurate to +/- 0.25 mm).  The 10:00 "Figure 8 face to BS HR face" measurement had to be done using the side of the scale in inches, with 1/32" tic marks (so accurate to +/- 1/64") and then converted to mm (so accurate to +/- 0.4 mm).  The measurements positions are listed like the BS HR surface is a clock, and assumes you are looking directly at the HR surface.  The below table gives those results:

The BS sits decently centered in the Figure 8 portion of the SUS cage, a little bit low and to the +X/+Y side.  I would say not as much horizontally as it looks from the table, given the inherent error with reading the scale (the BS is not wider than its 370.0 mm specification, it's actually 0.15 mm narrower at 369.85 mm).  The pointing implied by this measurement, however, is more than a little alarming.  The 2:00 and 10:00 measurements show a significant yaw of the BS optic w.r.t. the SUS cage, and in the same direction as the yaw of the SUS cage as measured by the FARO.  There is ~320.0 mm between the 2:00 and 10:00 positions on the BS, so that 1.45 mm difference in depth is a 4.53 mrad CW yaw.  When added to the CW yaw of the SUS cage, this measurement shows that the BS optic is yawed 5.62 mrad CW from its nominal yaw.  Even assuming the errors fall in our favor (so the 2:00 at 25.0 mm and the 10:00 at 25.8 mm), that's still a 3.59 mrad CW yaw (2.5 mrad BS and 1.09 mrad SUS cage).  In addition, the 6:00 measurement implies a significant downward pitch of potentially several mrad, although with no way to measure the top of the optic we can't actually measure it.  I have to be honest, I'm having a very hard time believing this measurement; we will revisit this once the BS cartridge has been moved to the test stand, where we have a better field of view for the FARO, more room to work and much better lighting around the BS, and can take direct measurements of the BS position and pointing using a total station and laser autocollimator (although there is no guarantee that the optic will be pointing in exactly the same direction after being craned across the LVEA).  More to come on this.

ISI Optics Table

The second attachment shows the ISI positions as measured by the FARO.  I've corrected the Z axis positions for the length of the rod we use to hang the SMR from the ISI so they give a better idea of the Z axis position.  Not much can be said here, as LLO discovered that while these rods are good for measuring the Z axis position, they are not at all good at measuring X and Y.  This makes sense as they were designed to be accurate in length and only length, so there's no guarantee that X and Y are repeatable.  We plan on measuring the X and Y errors of this particular set of rods in the coming days (align to a table with a known hole pattern, attach the rod and measure with the FARO, repeat multiple times to see how the X and Y positions change).  For now, we can say that the ISI is lower on the -X side vs the +X side, and lower on the +Y side vs the -Y side.  I'm not alarmed by the deviations in Z axis position, as this ISI was supposed to be lower by ~2.5 mm (to place the BS in proper Z axis position, since it's lower in the IFO coordinate system but the SUS is the same length as the QUADs), but this was never captured in the CAD files.

ITM Elliptical Baffles

The final four attachments show our survey of both ITM elliptical baffles.  Our view of the baffles and available fiducials to take measurements from were both limited, but we can say a few things.

ITMx Elliptical Baffle

We were able to get two points along the +Y bottom edge of the baffle, a single point along the +Y top edge, and single point near the center of the -X bottom edge of the baffle.  From this I made a couple of planes that represent the +Y and bottom sides of the baffle and are shown in the third and fourth attachments; I, J, and K are the direction cosines of the surface normal of the plane, while the listed angles are the angle from the surface normal to the +X, +Y, and +Z axes. Interestingly, the point on the top edge looks very well aligned, within 1.0 mm all around, while the points along the bottom of the baffle are all low by several mm.  In addition, there appears to be a significant upward pitch to the baffle.  Jim did note that when attaching the transport bracket he had to push the baffle in the +X direction to clear ~0.5 mm at the point where the bracket attaches to the suspended portion of the baffle.  This point is roughly 476 mm away from the baffle's suspension blade, so this is an ~1.05 mrad angle.  Applying this same angle along the bottom of the baffle box gives an ~ -0.33 mm Z axis move of that bottom -X edge of the baffle, so this does not account for the measured deviation.  In addition to the pitch, the bottom plane also shows a large roll (CCW when looking at the ITMx in WBSC3), while the side plane shows a large yaw (CCW when looking from the top down).  We know these baffle panels aren't exactly straight, so it's hard to say if this significant pointing is also present on the elliptical hole of the baffle (we couldn't see it, so we couldn't measure it directly).

ITMy Elliptical Baffle

Similar to the ITMx baffle, we were only able to get a handful of points along the -X side and the bottom of the baffle.  I made planes from these points representing the -X side and the bottom of the baffle (fifth and sixth attachments).  As seen with the ITMx baffle, the points along the top of the baffle all look good while the points on the bottom are too low by several mm.  There is a significant upward pitch to this baffle as well, as well as a large roll (CCW when looking at ITMy in WBSC1) and yaw (CCW when looking from the top down), although none are as large those as seen on the ITMx elliptical baffle.  Again, we could not see the elliptical hole in the baffle to measure it, so we can't say if this pointing is an artifact of the panels or also present on the actual baffle portion of the baffle.

This completes our in-chamber measurements of the WBSC2 cartridge assembly, and closes LHO WP 13171.

I also want to note, Ryan and I also preformed some in-chamber FARO measurements in WHAM3 (ISI, MC2 SUS cage, PR2 SUS cage, MC2 and PR2 baffles) on April 10th; I will post those as soon as I get a chance to process the data in PolyWorks.

Closes FAMIS 39955

Last checked in alog 89599.

All trends look consistent and/or similar with last month's with the exception of the EX pump, which Jim commented on last time. This pump was seen going up in pressure. This pressure has since remained stable.

WP 13154
a-Plus O5 SUS HAM5 (sush5) System Wiring Diagrams - D2300380
aLIGO SUS HAM 5-6 System Wiring Diagrams - D1002740

SUS-C7/ SUS-C8
Two HAM-A coil drivers were installed in the SUS-C7 rack, part of LO3. We decided to use the existing OMC cables for the new OFI. Cables are going to correct CER and field rack. OMC is being moved to the MER. Once HAM6 is vented the OM1/OM2/OM3 electronics and cabling will be removed.

SEI-C1
Started clean-up of the SEI racks. Removed a HAM ISI Interface Chassis from SEI-C1. This was part of the HAM1 L4C testing back in 2018. Plan is to remove the STS distribution electronics. See alog 89835 for testing of sending signals over IPC.

ISC-C3
The Heliax cable for SPI was landed in ISC-C3 (Patch Panel U37/U38, port 4) 

LVEA Work
Finished routing the ±18V power cable for CHETA Y around BSC8 and BSC1. Cable was landed in the TCS-R2 rack. We spent some time cleaning cabling in the TCS rack and the space between the TCSY enclosure and BSC1.

F. Clara, C. Gray

Monthly FAMIS Check (#39345)

T240 Centering Script Output:

Averaging Mass Centering channels for 10 [sec] ...
2026-04-06 09:03:52.267253
There are 11 T240 proof masses out of range ( > 0.3 [V] )!
ETMX T240 2 DOF X/U = -1.862 [V]
ETMX T240 2 DOF Y/V = -1.903 [V]
ETMX T240 2 DOF Z/W = -1.191 [V]
ITMX T240 1 DOF X/U = -2.423 [V]
ITMX T240 1 DOF Z/W = 0.37 [V]
ITMX T240 3 DOF X/U = -2.723 [V]
ITMY T240 3 DOF X/U = -1.215 [V]
ITMY T240 3 DOF Z/W = -3.11 [V]
BS T240 3 DOF X/U = -0.38 [V]
HAM8 1 DOF Y/V = -0.456 [V]
HAM8 1 DOF Z/W = -0.766 [V]
   All other proof masses are within range ( < 0.3 [V] ):
ETMX T240 1 DOF X/U = -0.079 [V]
ETMX T240 1 DOF Y/V = -0.076 [V]
ETMX T240 1 DOF Z/W = -0.114 [V]
ETMX T240 3 DOF X/U = -0.097 [V]
ETMX T240 3 DOF Y/V = -0.159 [V]
ETMX T240 3 DOF Z/W = -0.087 [V]
ETMY T240 1 DOF X/U = 0.027 [V]
ETMY T240 1 DOF Y/V = 0.07 [V]
ETMY T240 1 DOF Z/W = 0.259 [V]
ETMY T240 2 DOF X/U = -0.204 [V]
ETMY T240 2 DOF Y/V = 0.238 [V]
ETMY T240 2 DOF Z/W = 0.042 [V]
ETMY T240 3 DOF X/U = 0.267 [V]
ETMY T240 3 DOF Y/V = 0.048 [V]
ETMY T240 3 DOF Z/W = 0.007 [V]
ITMX T240 1 DOF Y/V = 0.28 [V]
ITMX T240 2 DOF X/U = 0.119 [V]
ITMX T240 2 DOF Y/V = 0.163 [V]
ITMX T240 2 DOF Z/W = 0.263 [V]
ITMX T240 3 DOF Y/V = 0.143 [V]
ITMX T240 3 DOF Z/W = 0.057 [V]
ITMY T240 1 DOF X/U = -0.045 [V]
ITMY T240 1 DOF Y/V = 0.16 [V]
ITMY T240 1 DOF Z/W = -0.038 [V]
ITMY T240 2 DOF X/U = 0.052 [V]
ITMY T240 2 DOF Y/V = 0.2 [V]
ITMY T240 2 DOF Z/W = 0.036 [V]
ITMY T240 3 DOF Y/V = -0.021 [V]
BS T240 1 DOF X/U = 0.043 [V]
BS T240 1 DOF Y/V = -0.119 [V]
BS T240 1 DOF Z/W = -0.038 [V]
BS T240 2 DOF X/U = 0.235 [V]
BS T240 2 DOF Y/V = -0.134 [V]
BS T240 2 DOF Z/W = 0.132 [V]
BS T240 3 DOF Y/V = -0.158 [V]
BS T240 3 DOF Z/W = -0.169 [V]
HAM8 1 DOF X/U = -0.297 [V]
Assessment complete.

STS Centering Script Output:
Averaging Mass Centering channels for 10 [sec] ...
 
2026-04-06 09:04:04.266410
There are 2 STS proof masses out of range ( > 2.0 [V] )!
STS EY DOF X/U = -4.57 [V]
STS EY DOF Z/W = 2.369 [V]
   All other proof masses are within range ( < 2.0 [V] ):
STS A DOF X/U = -0.496 [V]
STS A DOF Y/V = -0.768 [V]
STS A DOF Z/W = -0.628 [V]
STS B DOF X/U = 0.152 [V]
STS B DOF Y/V = 0.942 [V]
STS B DOF Z/W = -0.444 [V]
STS C DOF X/U = -0.995 [V]
STS C DOF Y/V = 0.908 [V]
STS C DOF Z/W = 0.636 [V]
STS EX DOF X/U = 0.606 [V]
STS EX DOF Y/V = -0.511 [V]
STS EX DOF Z/W = -0.372 [V]
STS EY DOF Y/V = 1.135 [V]
STS FC DOF X/U = 0.153 [V]
STS FC DOF Y/V = -1.192 [V]
STS FC DOF Z/W = 0.629 [V] 
Assessment complete.

FAMIS Link:  39345 

Only CPS channels which look higher at high frequencies (see attached) would be the following:

1. ITMx_ST1 V1
2. ETMy_ST1 H2

In the bash window got ZERO notes.

J. Kissel

More experience with the SPI in the optics lab yields an explicit ADC / DAC channel usage list for the SPI pathfinder. I've uploaded it as a part of G2401479-v2, but attached here for convenience. This kind of critical info / easy look-up table should be a part of the Altium wiring diagram, D2400111, but sometimes given there saturation of information it's nice to just have a look-up table especially when building front-end models.

Enjoy, future us!

FAMIS Link:  39344

Only CPS channels which look higher at high frequencies (see attached) would be the following:

1. ITMy_ST1 H3
2. ETMy_ST1 H2

In the bash window we get this note:

"BSC high freq noise is elevated for these sensor(s)!!!:       BSITMy_ST1_CPSINF_H3 "

TITLE: 03/24 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 14mph Gusts, 10mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.19 μm/s 
QUICK SUMMARY:

Arrived to see lots of tripped Watchdogs.  This was due to a M7.5 Tonga earthquake from last night just before 10pm local time (5utc).  Dave contacted me to give me the heads up on this and noted that ITMy actually had the Hardware Watchdog trip---this requires someone to go out to the CER to push a button to restore coil drivers.  We were hesitant on addressing this without Jim's guidance--not sure how powering things back on would affect the system.  Will message Jim with a heads up for BSC1's ITMy/BSC1-ISI/BSC1-HEPI.  Will continue bringing everything else back.

Other than that, today is Maintenance Day.  The Filter Cavity Tube has light flashing and so its small gate valves must still be open (I had thought the discussion was to close these gate valves to allow craning over the FC Tube, but not certain on this.

Day1 of 2-day CEBEX workshop begins today.

Hepi Pump Trends (Monthly) Famis 39954:
 

On Jan 26th the HPI-PUMP_EX_PRESS1_PSI started rising in maximum pressure. and on  maybe feb 2nd it started getting worse. Seems like it has plateau-ed on Feb 16th, but the Pressure still remains elevated.

That channel back in Oct was between 92.4-92.6 PSI. 
And now it's between 91.9 - 93.5 PSI. I'm not sure if this is out of bounds for HEPI.

Only CPS channels which look higher by eye at high frequencies (see attached) would be the following:

1. ITMx_ST1 V1
2. ITMx_ST2 V1
3. ETMx_ST1 V2
4. ETMx_ST1 H2
5. ETMy_ST1 H2

WP 13089
WP 13095

The following work was completed today:

1. Beckhoff media converter placed on rack 24V power. Previously powered by bench power supply.
2. TCSX 24V power and IR sensor cables replaced with appropriate length cables. Both TCS laser controllers for X&Y were keyed off. Power supplies output in MER disabled. This was done in precaution since the media converter work could disable TCS chillers.  Laser controllers keyed on and power supplies output enabled when work was complete.
3. Three HAM2 L4C cables pulled from SEI-C2 to HAM2. Jim W. sorting out final flange locations.
4. Two 8 AWG power cables pulled from CER Mezzanine to SUS-R2.
5. A DB37 cable was pulled from CER SUS-C2 to SUS-R1. Part of QOSEM upgrade.

Remaining work on SUS-R2 includes installation of power junction box, power sequencer, and a ±18V power strip.

F. Clara, J. Figueroa, M. Pirello and R. Thompson