Travis, Melina, Jordan

Per the updated HAM6 VE drawing (D0901823), we moved the HAM6 turbopump and pump out spool from the top D7 flange to the -Y door BF3 port. The 12"CF ->10" CF adapter, gate valve, pump out spool and turbo pump were removed and replaced with a single 12"CF blank on the D7 flange. We also replaced the turbo with a 500 l/s Leybold maglev turbo compatible with the SS500 pump carts.

The turbo assembly (with GV closed) was pumped down and helium leak checked. Each joint sprayed with a 5s dwell of He, no signal observed above the leak detector background of 3.6E-10 Torr-l/s. Remaining chamberside flanges will be He leak checked during corner pumpdown.

Rahul, Elenna, Oli, TJ, Camilla, Jim, Betsy. WP12419

Following yesterday's work 83820, this morning we removed all remaining ISC components on HAM1. Rahul removed RM1, RM2 and the SEI 10kg weights (bolts are in foil pouches with the weights).

Everything has been placed on a rack in the HAM1 cleanroom, labeled photo attached. The beamdumps are ordered as shown, BD17 and 18 are the largest plates (BD naming convention in D1000313 v17 Cartoon). Which pan each optic is in has been added to the D1000313 googledoc along with any optic serial numbers that could be read, our current working copy of the document is attached. 

After lunch, TJ removed the platforms/stairs around HAM1 and Rahul, Jim and I removed all the ISC and SUS cables. All DB-25s were stored in foil in the ISC components rack (bottom shelf) and the RF cables have been given to Fil for rework. 

Wed Apr 09 10:11:18 2025 INFO: Fill completed in 11min 14secs

J. Kissel, B. Lantz, E. Bonilla, O. Patane

Very alarmed but how *apparently* different the in-air vs. in-vac TFs for H1SUSSR3 were -- see original plots in LHO:83818, and alarmed commentary in LHO:83819 -- Brian suggested "are you *sure* you've plotted the same DOF to DOF comparison on some of these plots?"

He was right. I re-exported both the 2024-08-01 in-air transfer function set and 2024-08-08 in-vacuum set from the DTT templates. The in-air TF's exported text files showed a diff with what was in the svn on the L, T, V, and Y drives. So, all the TFs that were "very interesting" in the above mentioned commentary were "very interesting" because they were comparing apples to oranges, and treating that orange as an apple.

So, here, I attach the same comparison for SR3, but with the fixed in-air data set.


                 D R I V E   D O F 
          L     T     V     R     P     Y

     L    --    meh   nd    meh   eand  YI
 
R    T    meh    --   meh   eand  meh    meh
E 
S    V    YI    YI    --    YI   nd    YI
P
     R    YI    eand  YI    --    YI    meh
D 
O    P    eand  VI    YI    meh   --    meh
F
     Y    YI    nd    meh    nd    nd   --

Recall the legend is 
  VI = Very Interesting (and unmodeled); very different between vac and air.
esVI = Modeled, but Still Very Interesting; very different between vac and air
  YI = Yes, Interesting. DC response magnitude is a bit different between vac and air, but not by much and all the resonances show up at roughly the same magnitude.
 meh = The resonant structure is different in magnitude, but probably just a difference in measurement coherence
eand = The cross coupling is expected, and not different between air and vac.
  nd = Not Different (and unmodeled). The cross-coupling is there, but it doesn't change from air to vac.


Thankfully, 
- there are WAY less "very interesting," only the T to P (page 22) remains.
- the matrix is more symmetric, and
- the changes between air and vac are LOT less dramatic.

We'll continue to discuss.

Morning dry air skid checks, water pump, kobelco, drying towers all nominal.

Dew point measurement at YBM in prep for BSC1/8 work, -42C

Starting around 22:13 Tue08apr2025 the MX weather station wind speed anemometer stopped recording. The other MX sensors, for example outside temperature, continue to run.

Attachment shows wind speed and temp for EX top row, and for MX bottom row.

TITLE: 04/09 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: MAINTENANCE
    Wind: 4mph Gusts, 2mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.21 μm/s
QUICK SUMMARY:

Plans for today:

• JIM/MITCH - HAM1 Offload HEPI Setup, disconnect actuators (continued)
• HAM1 - ISC component (continued) (Camilla, Oli, Elenna, Rahul, TJ)
• MID Station forklift - Transport and Load in ISI de/Install fixtures, wipe down, crane into place
• BSC1 (via BSC8) - CPY work starts - crew to map beams inside at spool (Betsy, Robert, Sheila, Tony)
• Randy - Remove platforms from HAM1
• HAM1 - Remove all cables form chamber
• HAM1 CRANE/FORKLIFT - SEI Stack removal
• RANDY - Crane 3IFO Flange crate over BT to first stop West Bay for later X-Arm traverse
• HAM6 VAC - Move turbo from top to back door (continued)

Today's activities:

• Y-manifold purge air header connected to purge valve. Purge air flow rate was adjusted according to removal state (door still bolted, bolts loosened, C3 cover on).
• BSC8 -X (South) door was removed. 
• HAM6 turbo pump, reducer, and gate valve removed from top D7 port. Will be replaced with a blank.
• Viewport removed from HAM6 -Y door, port BF2.  Will be replaced by new Leybold turbo and reused reducer/GV.

J. Oberling, R. Crouch

Today we took pre-deinstall measurements of the position of the optical table surface of the WHAM1 passive stack.  The plan was to use the FARO to measure the coordinates of several bolt holes, using a threaded nest that locates the Spherically Mounted Retroreflector (SMR) precisely over the bolt hole, on both the +Y and -Y side of the chamber.  This, unfortunately, did not happen in full due to the untimely death of the FARO's climate sensor (or the FARO's ability to read the climate sensor, we're hoping for the former).  The FARO cannot function without this sensor as it relies on accurate measurements of the air temperature, relative humidity, and air pressure to feed into a model of the refractive index of air, which it needs to accurately calculate the SMR distance from the FARO.  We did manage to get a few points measured before the sensor died.  I've reached out to FARO tech support about getting a new climate sensor and should hear back from them tomorrow (they usually replay in 1 business day).

Summary

We were able to get measurements of 3 bolt holes, all in the furthest -Y line of bolt holes, and an old IAS monument from aLIGO install before the FARO's climate sensor died.  The results are listed below under the Results heading.  The most interesting thing here is there appears to be an error in WHAM1 placement in the x-axis, as the bolt holes we measured are all ~37.25 mm too far in the -X direction from nominal.  We also set a scale on the wall across from the -Y door of the WHAM1 chamber that is registered to the current elevation of the optical table; placing an autolevel so it sights 150.0 mm on this scale (sighting the side of the scale with the 0.5 mm tick marks) places that autolevel 150.0 mm above the surface of the passive stack's optical table.

Details

We started on the -Y side of the WHAM1 chamber.  The FARO was set with a good view of its alignment monuments and the passive stack's optical table.  We ran through the startup checks and calibrations without much issue (we did see a return of the odd 'ADM Checks Failing' error, which had been absent for about 1 month, but it immediately went away and didn't come back when we performed a Go Home operation).  FARO monuments F-CS026 through F-CS035, inclusive, were used to align the FARO to the LHO LVEA local coordinate system; the 2 standard deviation device position uncertainty after this alignment was 0.016 mm (PolyWorks does 100 Monte Carlo simulations of the device position).  This complete, we started measuring.

First, as a quick test of the alignment we took a look at old IAS monument LV24.  This monument was used to align the WHAM2 ISI during aLIGO install, and its nominal X,Y coordinates are [-20122.0, -3050.7] mm (there is no z-axis coordinate as we were not setting these in Z back then, a separate set of wall marks was used for z-axis alignment).  The results are shown in the 1st attached picture; again, ignore the z-axis results as I had to enter something for the nominal or PolyWorks wouldn't accept the entry, so I rounded to the closest whole number (this isn't even the surface of the monument, it's the point 2" above it where the SMR was, due to use of the Hubbs Center Punch Nest (which has a 2" vertical offset when using a 1.5" SMR)).  Knowing how we had to set these older monuments, since I'm one of the people that set them, I'm not entirely surprised by the X and Y deviations.  The monuments we set for aLIGO install (the LV monuments) were placed w.r.t. a set of monuments used to align iLIGO, which themselves were placed w.r.t. the monuments used to install the vacuum equipment during facility construction (the PSI monuments), which themselves were placed w.r.t. the BTVE monuments which define the interface between the arm beam tubes and the LVEA vacuum equipment, which we then found errors in their coordinates during our alignment of the FARO during the O4a/b commisioning break in 2024.  Not at all surprised that errors could have stacked up without notice over all of those monuments set off of monuments set off of monuments set off of...  Also, take note of the x-axis coordinate of this monument, this will be important later.

We then set about taking measurements of the passive stack optical table.  To map the bolt holes we measured we used an XY cartesian basis, assuming the bolt hole in the -X/-Y corner was the origin.  We then proceeded to increment the number by the bolt hole (not distance), following the same XY axis layout used for the IFO.  Using this scheme the bolt holes for the table corners were marked as:

• -X/-Y: (0,0)
• -X/+Y: (0,32)
• +X/-Y: (36,0)
• +X/+Y: (36,32)

We were able to get measurements for bolt holes (0,0), (14,0), and (25,0).  We were in the process of measuring bolt hole (36,0) (the +X/-Y corner bolt hole) when the FARO's climate sensor died.

To get the coordinates for the bolt holes I used the .EASM file for WHAM1 with the passive stack configuration located at D0901821-v4.  From the assembly, using eDrawings, I was able to get coordinates w.r.t. the chamber origin for the bolt holes we measured.  Those were then added to the coordinates for the WHAM1 chamber, in the LVEA local coordinate system, to get nominal coordinates for the bolt holes.  I also had to add 25.4 mm to the z-axis coordinates to account for the 1" offset of the nest we were using for the SMR; the center of the SMR sits 1" above the point being measured, so I needed to manually add that offset to the nominal z-axis coordinate of the bolt hole.  For reference, according to D0901821 the global coordinates for WHAM1 are [-22692.0, 0.0, 0.0] mm; when converted to the LVEA local coordinate system (removing the 619.5 µrad downward tilt of the X-arm) this becomes [-22692.0, 0.0, +14.1].  The measurement results are shown in the 2nd attached picture.  Notice those x-axis deviations?  Remember the measurement we made of LV24?  Clearly the FARO alignment is not 37 mm off, as the measurement of LV24 showed, so something is definitely up with the x-axis coordinate of the WHAM1 chamber (error in chamber placement?  aLIGO WHAM1 is the iLIGO WHAM2 chamber, moved from its old location next to WHAM3).

Results

We can do some analysis of the numbers we have, although limited since we only have 3 points in a line.  This really only applies to the furthest -Y line of bolt holes on the table, since we weren't able to get measurements of the +Y side to get a more full picture of where the table is sitting, but it's something.  Position tolerances at install in 2012 were +/-3.0 mm in all axes.

• X-axis position: Not much we can do here without knowing what the actual x-axis coordinate of WHAM1 is.  It clearly isn't where the SYS drawings say it should be.
• Y-axis position: ~0.41 mm +Y from nominal
• Z-axis position: ~0.76 mm +Z from nominal
• Pitch: ~99 µrad down
• Yaw: ~83 µrad CCW

I do want to note that D0901821-v4 claims the table surface should be -187.8 mm in LVEA local coordinates (-201.9 mm in global), but this is not the number we used when installing the passive stack in 2012.  In 2012 we used -185.9 mm local (-200.0 mm global), as can be seen in D0901821-v2.  To compare our measurements to the install numbers I changed the nominal z-axis coordinate to match that of our install target (-185.9 + 25.4 mm SMR offset = -160.5 mm) and the results are shown in the final attached picture.

Wall Scale Registered to Current Table Surface Elevation

To finish, we set a scale on the -Y wall directly Crane East of the WHAM1 chamber and registered it to the current elevation of the passive stack's optical table.  To do this we used a scale provided by Jim (the scale was in inches, with 0.01" tick marks) and an autolevel.  We set the autolevel at a fixed elevation on the -Y side of the chamber.  The scale was then placed at each corner of the optical table, starting with the -X/+Y corner, and the autolevel was used to sight the scale; only the scale was moved, the autolevel was fixed (rotated only to follow the scale, but not moved otherwise).  We then averaged the 4 scale readings to get the table elevation, set the autolevel to this reading with the scale back at our starting point (we actually didn't have to move it, thankfully), and then set a scale on the wall using the autolevel.  The 4 scale readings:

• -X/-Y: 5.89"
• -X/+Y: 5.90"
• +X/-Y: 5.90"
• +X/+Y: 5.91"

The average of the 4 readings is 5.9", and since the autolevel was already sighting 5.9" on our starting point at the -X/+Y corner we left it there.  This may seem high, but we had to have the autolevel high enough that we could see over the various components mounted to the table surface.  We then turned the autolevel and set a scale on the wall.  This scale was in mm (since that's what we had), but this worked out OK.  5.9" is ~149.9 mm (149.86 mm to be exact), so we set the wall scale so it read ~149.9 mm when sighted through the autolevel.  So a 150.0 mm reading on this scale (sighting the side with the 0.5 mm tick marks) is ~150.0 mm above the current position of the passive stack's optical table.

This closes LHO WP 12442.

This morning, we added dial indicators to the ends of the support tubes to monitor the support tube locations on the -X side. We had to remove a cable tray to get room to do this under the chamber. They are protected under the chamber, but there is a bunch of loose cabling on that side that could bump my set up. Unfortunately, we don't have access to the northside. Not quite sure how to track the support tube ends on the +X side when we float HEPI yet.

While Betsy and crew were pulling parts in chamber, Mitch and I were disconnecting actuators at the piers. Vertical actuators are quite difficult, access is very tight, going to be hard reconnecting them. Horizontal actuators are a lot easier, but we are adding .100" shims and bolts to protect the bellows and IPS, we lost a couple shims inside one of the actuators and it was a struggle to fish them out. We are adding wires to the shims going forward to prevent that mishap. We'll get the other 2 actuators tomorrow. So far dial indicators show we are still in the same spot as before disconnecting the actuators.

[Betsy, Camilla, Elenna, Oli]

We cleared half of the HAM1 table today on the +y side. This cleared optics on the ALS and POP paths, and the first part of the optics on the REFL path. We carefully labeled each component, and Oli logged component and cable names with serial numbers. Betsy laid the components in clean pans lined with cleanroom cloths. The cables are still attached to the feedthroughs and were left lying at the bottom of the chamber.

Attached photos show cleared side of the table.

Before removing components, we reviewed the table layout after Ibrahim and TJ noticed some discrepancies between the solidworks drawing and the optic locations as depicted in Corey's pictures from yesterday. We confirmed that there are some dispcrepancies between the two. TJ has a more detailed report.

TITLE: 04/08 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

More vent work today. I was able to mark some things fully or partially done, but others I'm unaware of their current status

DONE            FAC - 2nd Cleaning BSC8
DONE            Investigate large shifts in trends of PRM and PR2 in YAW (83807, 83808)
DONE            IAS - HAM1 Stack table survey
PARTIALLY   JIM/MITCH - HAM1 Offload HEPI Setup, disconnect actuators
PARTIALLY   ISC - HAM1 - ISC component removal
PARTIALLY   VAC/FAC - BSC8 Door Off - CRANE to Caddy
                       VAC - Start Feedthru Swap
                       EE - HAM4-5 Cable tray work - Ken, some Crane usage
                       IAS - HAM1 support tube ends?

LOG:                                                                                                       

Closes FAMIS37251

There's some known issues right now with the dust monitors. We can still see LAB1 not writting to the network, EY died for about a day, LVEA5 not writting anything for a few days, TJ swapped this one today with one from staging. The counts were not exactly as expected across both particle sizes, so I'm going to test this one a little more.

I brought LVEA5 over to LVEA10 in the biergarten and tested them side by side and saw similar results, I also did the zero count test on LVEA5 which it passed.

Jeff asked me to plot a comparison for SR3 M1 between all degrees of freedom comparing it in vacuum versus in air. I've plotted the last two measurements taken for SR3 from last August at the end of the OFI vent. One measurement was taken in air, and the other was taken in vacuum The pressure for the in vacuum measurement wasn't all the way down to our nominal, but as Jeff said in his alog at the time when we were running these measurements: "most of the molecules are out of the chamber that would contribute to buoyancy, so the SUS are at the position they will be in observing-level vacuum" (79513).