Jonathan, Erik, Patrick, Dave:

This afternoon Jonathan installed the new IOC-LAN on the service-host cluster, which increased the number of IP addresses available to containerized IOCs from a few dozen to 64k. The IOCs were restarted and assigned new addresses on this VLAN (10.23.0.0/16) [see attached dashboard]

For a brief period while the server was being updated we ran pt100a's IOC on opslogin0.

The EDC was restarted on h1susauxb13 to include 10.23.255.255 in its CA_ADDR_LIST UDP broadcast list. Similarly on cdslogin the alarms service's puppet config was updated and alarms was restarted.

TITLE: 05/20 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:
Lots of good work done today. Jason and crew made IAS progress over on the Beam Splitter.
Oli and Ibrahim have been working with the B-OSEMS over at the new BS too.. 
Vac team did some RGA baking and pump carting as per usual.
The SEI crew cleaned some CRS optics and worked on HAM3 feed throughs.
X are has been de-tumbleweeded with the big Green Machine.

LOG:

R. Crouch, J. Oberling, I. Abouelfettouh, O. Patane

As Ibrahim reported here, we have completed the first round of BBS position alignment (I say first round as we still have to do the pitch/yaw alignment, and that has the potential to change the position alignment so we may be doing this again).  In the basis of our alignment equipment, which is set normal to the AR face of the BBS, the deviations from nominal are:

• Horizontal: +0.3 mm (right)
  • Tolerance: +/- 1.0 mm
• Vertical: -0.1 mm (low)
  • Tolerance: +/- 1.0 mm
• Longitudinal: +0.4 mm (long)
  • Tolerance: +/- 1.0 mm

If we rotate these deviations to the XYZ axes using the BBS yaw we get deviations along those axes.  I'm using the target BBS yaw for this (specifically, the AR surface yaw from the +X axis of 45.1056°), as we have yet to measure or align the actual BBS yaw, so this is more of an estimate at this point but will work for now (it takes a yaw change on the order of several degrees to change this calculation at the 0.1 mm level, so this is a pretty good estimate); this will be tightened up once we align the BBS pointing and revisit the positioning.  The results (the tolerances rotate with the deviations, hence the change in X and Y):

• X: -0.1 mm
  • Tolerance: +/- 1.4 mm
• Y: +0.5 mm
  • Tolerance: +/- 1.4 mm
• Z: -0.1 mm
  • Tolerance: +/- 1.0 mm

The below table gives the target position of the center of the BBS's AR surface and the current position based on the above estimate of the XYZ deviations (all units are in mm):

The next step in the alignment is to use the FARO to set up a total station/laser autocollimator combo looking along the target surface normal of the HR surface of the BBS.  This will be used to align the BBS pitch and yaw.  Once that is done we'll have to re-check the BBS position alignment (again, using the AR surface of the BBS) to ensure the pointing alignment did not change the optic's position (which may happen in this case as the BBS is currently, as Ibrahim reports, "quite yawed").

Ibrahim, Oli, Jason, Ryan C

Work done today:

• Oli and Ibrahim added BRDs to PUM
• Oli and Ibrahim added AOSEM flags after confirming polarities. These are now correct.
• Ryan C and Jason measured the optic to tell Oli and Ibrahim how to move the optic.

Specifics of Optic XYZ Alignment

• Height/Vertical: 100g of mass was removed from the Top Mass to bring the height of the optic into spec, which is now within 0.1mm of target.
• Transverse/Side-Side: Was already within spec - within 0.3mm
• Length/In-Out: Now within 0.4mm of spec - was originally out by 1.3mm but we moved the top stage blades.
• The optic is now quite yawed so we will likely have to play around with Length since the top stage blades were nearing maximum distance.

See pictures below.

Conclusion: T2000599-v6 (r13010) of bbssopt.m matches LHO parameters, T2000599-v5 (r12764) matches LLO's current configuration, but the difference in the models is negligible

The M3 mass listed in the bbssopt.m parameter set has been changed from 20.99kg to 20.909kg to match the mass of LHO's BBSS M3 optic.

This mass is given by the mass of the optic itself (20889g) + the mass of the primary prisms (7.56g and 7.46g) + the mass of the secondary prisms (5.57g together). This gives us 20.909kg. The change in the model from this is very minimal - the highest Pitch peak shifts down by a few hundreds of uHz, from 1.1656Hz to 1.1615Hz.

LLO's BBS02 is 21.065kg, and comparing this to the previous dummy's mass, the peaks are still in the same place, so the previous version of the model, v5 (r12764) matches with their current configuration, but since the shift is so minimal, using the same model that LHO is using would be fine.

I've updated T2000599 to -v6, and committed /ligo/svncommon/SusSVN/sus/trunk/Common/MatlabTools/TripleModel_Production/bbssopt.m to r13010.

The comparison for all DOFs for all three mass changes can be found at /ligo/svncommon/SusSVN/sus/trunk/BBSS/Common/Results/comparetripleparams/2026-05-20_M3_DummyvsLHOvsLLO/triplemodelcomp_2026-05-20_M3_DummyvsLHOvsLLO_M1toM1.pdf and committed to svn as r13011.

TITLE: 05/20 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: 2mph Gusts, 0mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.16 μm/s 
QUICK SUMMARY:

We are currently in LASER SAFE for some BBSS and tomorrow's VAC work, but might go back to HAZARD in the afternoon for more HAM2 work.

Here's a look at some old data from september's OM2 heating test. I'm posting this incomplete alog, which has been sitting in my drafts for a long time, so that at least this information is available to people.

Background about the measurements:

Information about this dataset, bold numbers are used as assumptions in these models:

• I summarized measurements from Sept 4th in 86785, and estimated that kappa c was 1.1% lower with OM2 hot than cold, implying that the IFO to OMC mode mismatch is 2.2% worse with OM2 hot than cold.  In the models I'm making I let the IFO to OMC mode matching be perfect for cold OM2, and 2.2% mismatch for hot, although they could both be worse than that.
• Matt measured the sqz to OMC mode matching with an OMC scan for OM2 hot to be 6.8% in 88060  (This is with ZM4 strain guage at 6.2V, in Sept when this measurement was made it was at 6V, but the mode match depends only weakly on ZM4 as shown in Leo's measurements, ZM5 has been at -0.4V for many months).
• For OM2 cold, the SQZ to OMC mode mismatch was 2.8% 88088
• Camilla took a dataset for comaprison with OM2 cold in 86777, nonlinear gain 22.9
• We took sqz data with OM2 hot in 86736, with nonlinear gain measured to be 24.0
• While OM2 was hot, Camilla and Elenna did the "brontosaurus" measurement, where they used FIS to measure rotation and varied the SRCL offset, 86737.  Elenna used the usual fitting code here, which assumes that the rotation is due to the SRCL offset.  P2500132 section IV D discusses this, that the squeezing rotation caused by exteral mismatches (ie, sqz to OMC or IFO to OMC) are indistinguishable from the rotation caused by SRC detunings.  Based on the linear fit, they changed the digital offset in the SRCL servo, we can use their fit for the slope to say this was change of 0.0134 radians in the SRCL offset, although probably not actually bringing the SRCL detuning to zero. I don't believe that we did a sensing function measurement which could distinguish between the squeezer mode mismatch and actual SRCL detuning.
• Retook OM2 hot data set with the new SRCL offset, still NLG of 24.0 86739
• We have known squeezer injection losses of 7.3% and known IFO readout losses of 10%: loss tracking gsheet

Here is a plot with all of this data, we took mean sqz data for all three data sets with the LO unlocked, we only took anti-squeezing data for the first OM2 hot data set without adjusting the SRCL offset.  The low frequency non quantum noise is worse for the OM2 hot data because we didn't retune the feedforwards after heating up. 

Some gwinc plots to help me understand the impact of mismatch phase:

In gwinc the mismatch is parameterized as IFO to OMC, and SQZ to OMC, since we have not adjusted the psams while we heated up OM2 we will need to increase both of these mismatches for the hot OM2 state, and both of them have a mistmatch phase which changes the frequency dependent rotation significantly.  This rotation is most obvious for the mid- squeezing traces, where we adjusted the squeezing angle so that the high frequency noise matches what it is when there is no squeezing.  To help myself understand, I made some plots that show a series of models with our measured mismatch magnitudes listed above and the squeezing angle fit for high frequency, varying ifo to omc mismatch phases, or sqz to OMC mismatch phases.  Here is another plot showing only one type of mid sqz with both phases varying, which may also be helpful to look at to see the envelope of what varying the mismatch phase can do.  Kevin has said that the only thing that matters is the relative mismatch phase, this plot illustrates that where most of the traces can't be seen because they are hidden by others with the same relative mismatch phase.  The traces where two mismatch phases are identical are closest to the trace with no mismatch.  

Looking at losses:

Looking at the plot with all the data, you can see that the mean squeezing is mostly the same for the three cases, above 200 Hz, suggesting that the losses are about the same for all three cases.  Below 200 Hz, there is as usual some kind of extra noise that makes the mean sqz trace not useful for estimating loss.  We only measured anti-squeezing for the hot OM2 case before we added the SRCL offset. This  plot of a model of anti-squeezing shows that we don't expect much difference in anti-squeezing for the level of mode mismatch and SRCL offset that we have, except around 20Hz where technical noise would cover the quantum noise.  

There are two ways to use these data to estimate unknown losses.  I've used 2-2.3kHz since the technical noise is further from the shot noise than in other parts of the spectrum.  Assuming an arm power of 330kW we can use no sqz data to estimate readout losses, doing that we need to add just a small amount of extra losses to explain our shot noise: 1.5% for cold OM2, 2.4% for hot OM2 no change in SRCL offset, 0.9% for hot OM2 with SRCL offset changed.  This is encouraging since it means that we can account for most of our readout losses, however it doesn't agree with the estimate based on kappa C for the change in losses as OM2 was heated.  We can also use the nonlinear gain and unlocked squeezing level to estimate unknown loss: cold OM2: 15.1%, hot OM2: 15.7%, hot OM2 SRCL offset:  19.8%.   

J. Kissel

Picking up from yesterday's work (2026-05-18, LHO:90270), today I:
    - Verified Bram's idea on how to resolve yesterday's UNSOLVED SIDEQUEST (1) regarding ~120 Hz noise seen on FBR_PWRIN_REF PD (LHO:90279) -- it's just the room lights. Check out this pic of o-scope timeseries of that PD readout with no lights, room lights, then clean room lights on. *sigh* Alright. RESOLVED: no big deal; when I want to use that PD, turn off the lights.

    - Resumed migration of optics:
        . Finish up REF beam path by migrating and installing M_B3 to steer REF beam into IFO_MEAS_A. Confirmed that Reflective surface is within the mount, and protruding AR surface faces M_M2 and IFO_MEAS_B. 
        . Nothing to align here, it's a fixed optic, but checked alignment of REF beam into both IFO_MEAS_A and IFO_MEAS_B with irises in D2400143 breadboard holes 85 and 82.
        . Migrated D_IFO_MEAS_A and D_IFO_MEAS_B and aligned PD reflection into them with slop of PD housing moutning holes
           :: For D_IFO_MEAS_A Changed out smaller 1.0"x075" D1800140 Type 07 plate for bigger 1.16" x 1.16" D2000228-v1 DLC coated plate that we'd found to rectify the (lesser) stray beam from FBR_PWRIN_REF during D2400107-v4 build. As discussed, in the D2400107-v5 build, we're gunna need a whole different solution (LHO:90277).
        . Migrated and aligned M_B1 using holes 103 and 94.
        . Migrated M_M1, but needed to swap left-handed mount with right-handed mount due to interference of pico motor body with alignment pegs. More on this in the comments.
        . Aligned M_M1 using holes 92 and 87 (M_M4 and M_M5 are NOT installed)
        . Secured alignment adjustment screw set screws for M_F1 and M_B1 since these shall never be touched again. Tweaked M_M1 alignment to follow minor beam change when securing those screws.
        . Migrated and aligned M_M4 using holes 81 and 79
        . Migrated and aligned M_M2, and 
        . et voila! A little tweak of M_M2 and I had a heterodyne beat note to use for finishing alignment.

Attached are End-of-day board status, and the MEAS IFO heterodyne victory lap.

Crude estimate of the efficiency (without accounting for dark offsets): 
        Max = 6.60 V
        Min = 1.08 V
        Amp = 5.52 V
	Mean = 3.85 V
	
        efficiency = Amp / (2*Mean)
        MEAS A     5.52 / (2*3.85) = 0.717 = ~72%
        MEAS B     5.52 / (2*3.82) = 0.723 = ~72%
Excellent.

Tomorrow we install the last two optics and align the REF IFO, and we're back in business!
Estimated readiness for install May 26 2026!

As per WP 13257 we configured the network to create a dedicated subnet for IOCs and other services.  This is in support of our work to improve our infrastructure and management of IOCs and services in CDS.  This included network switch reconfiguration and extending the CDS environment.  The edc will need a restart to be able to see the new subnet.  This will be held off until we actually put something in the network that it needs to record.

Starting with yesterday's alignment, we tried to move the beam spots on IFI input baffle (using IM1), IFI output baffle (using IM2) and the baffle in front of IM4 (using IM3).

We had to make a huge change in all of the optics used: IM1 yaw: -500 urad, IM2 yaw: -900 urad, IM3 yaw: -720 urad.

Forgot to measure PIT/YAW position of IM4_TRANS (and we cannot trend it as we need fast data of segments) but the beam was on IM4_TRANS with almost full IM4_TRANS_SUM.

IMs didn't rail but this is clearly NOT the right way to move. Instead, what we need seems to be to shift the beam position on MC3 by a few mm in -X-Y direction.

We didn't bother to move PRM nor IM4 so the IFO REFL was again misaligned badly.

(One thing to note is that with this drastic change in the input alignment, the beam was still hitting the IM4 TRANS but not ISS QPD. However, just by turning IM3 we were able to regain the beam on ISS QPD. Now I'm fully confident that, whatever alignment we end up having after pumping down, as far as the beam is on IM4 TRANS, we can find the beam on ISS QPD by scanning IM3 (and IM2 if necessary) and slowly walk the beam using the picos to have a good alignment in the ISS path.)

We also measured the beam position (both height and Y position relative to the ideal beam path measured at specific X coordinate) to better understand the IMC beam. Numbers are to follow, but the gist is that the beam position is good (i.e. likely centered) on MC3 but is off in -Y direction by 3mm or so on MC2 even though MC TRANS is close to center.

So, for tomorrow:

• Finish the beam position numbers for IMC.
  • Starting from there, see how much beam spot moves on baffles when we center the beam on MC2 AND move the beam spot by a few mm in -X-Y direction on MC3.
  • Figure out how much we have to move JM3, MC1, MC2 and MC3 to cause such a change.
• If we can do that calculation before noon,
  • Transition to hazard in the afternoon.
  • See IM4_TRANS PIT and YAW.
  • Back off the changes we did today (Tuesday).
  • Change JM3, MC1, MC2 and MC3, refine to get decent flashes.
  • Use IM2 and IM3 to unclip the beam on IM4 baffle.
  • See IM4_TRANS PIT and YAW. Adjust IM3 further to steer the beam on IM4_TRANS where it should be.
  • Check IM4 baffle again.
  • Check the beam position on PRM.
  • Use IM4 to steer the beam on PR2. Measure the beam position on PRM and  PR2 like we did for MC.
  • Make sure that the beam is retroreflected by PRM as good as we can. See the IFO REFL beam on the baffle before HAM2-HAM1 septum window.

My guess is that the beam has been (at least very close to) clipped by some of the IO baffles for a long time, and the above practice is to see if there is an alignment where the beam is at least not clipped.

H1 ISI CPS Noise Spectra Check - Weekly Famis 39342
For some context, most of the Corner station is vented and the BS cartridge is not in the chamber which explains what is shown on the BS plots here..

TITLE: 05/19 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: More alignment work in HAM2 and BBSS alignment today. Now that the LVEA is back to Laser SAFE, more alignment steps for the BBSS and prep for the GV7 repair can be done starting tomorrow. The SPI NPRO continues to run overnight in the optics lab with proper curtains and signage in place.
LOG:

A Norco tech came to the site to inspect the 8 LN2 dewars that feed the cryopumps. Inspection report will be posted to Q2000008 once received.

- No major issues found, some small leaks were repaired as they were found. The tank safeties and burst disks are due for replacement soon, since they should be replaced every 5 years.

The vacuum jacket pressures were also measured during inspection:

The vacuum jackets were all pumped down to <10 mtorr last May (excluding CP4 which is not in use), see alog 84290

While the corner station old HEPI pump controller (aka the Ben Box) is down and before the new Beckhoff replacement is rolled out, I've created a dummy ioc which serves the old channels. This has "greened up" the EDC, it no longer has 31 disconnected channels. To appease the alarms system, the PRESSn channels have non-zero values which lie in the good range. CDS now has zero active alarms.

I took the opportunity to update my docs on testing/installing containerized IOCs.

[Keita, Rahul, Elenna]

Today I moved IM2 and IM3 to bring the beam back to our reference position on IM4 trans QPD and center it on ISS QPD after Keita's move of the mode cleaner mirrors in 90259. This requires some iteration back and forth on both suspensions.

Our desired positon on IM4 trans is P = 0.22 and Y = -0.06. On ISS QPD, it is centered, so P=0 and Y=0.

We are driving MC2 in length, so the mode cleaner is flashing, and there are bright flashes on the QPDs. I am pausing ndscope on a flash and measuring the height of the peak in the fast channel and calculating the pit and yaw position from each QDP segment.

Unfortunately, this still results in clipping on the baffles Keita notes above, so we will keep going.

At the nominal IM4 trans position, yaw is pretty well centered. I then moved IM2 to both edges of IM4 trans QPD.

I changed the IM2 yaw slider to -250.7, which brought the yaw position on IM4 trans to 0.85. This made the clipping worse.

I changed the IM2 yaw slider to 90.3, which brought the yaw position on IM4 trans to -0.88. This was still not good enough to fix the clipping on the baffle.

By making a very large move to IM2 yaw slider value of 710.3, this centered the beam in the IM4 baffle. This is a ~800 urad move according to the osems and slider. The IFO REFL beam is still clipped.

I undid the 800 urad move, so the IM2 yaw slider is back to -88.7 for now.

Keita and Rahul went out to measure the position of the beam on MCs 1,2 and 3. We think that we need to make a move of these three mirrors to see if we can unclip the beam on these baffles that way.

We want to note that the positive yaw move of IM2 corresponds to unclipping on the IM4 baffle, this is consistent with the beam motion observed in chamber in the -X direction. However, this is contradictory to the sign on IM4 trans QPD, which was moving to negative yaw when we did this move. We suspect that the segment defintion must be wrong somewhere.

Keita will say more later once we have a chance to analyze the positions in chamber.

To clarify, the slider values of IM2 and IM3 are left at the "end" positions on the table above.

J. Kissel

Picking up from last Friday (2026-05-15, LHO:90253), today I:
    - Secured D_R_P1 and D_M_P1 and confirmed that TFP REFL beams went into the dumps
    - Started aligning REF path and migrating optics over from the D2400107-v4 breadbord's CVM100 mounts into / onto D2400107-v5 IXM100 mounts:
        . R_M1 migrated.
        . Re-set up the power meter gantry assembly (since its only me, and I need the power meter stable for maximizing throughput thru irises)
        . Placed irises in holes 83 and 84, adjusted R_F1 and R_M1 to walk and align the beam thru irises, confirming with IR camera view of iris holes and power meter thru-put. 
        . Secured R_F1 and R_M1 IXM mount 8-100 alignment screw shaft set screws, since these optics shall not move again.
        . R_B1 migrated.
        . Aligned beam through holes 86 and 95, repeating process above, but only adjusting R_B1.
        . Uncapped IFO_REF A and B PDs, PWRIN_REF PD and hooked them up to the o-scope (discovering a minor re-cabling issue; see LHO:90268)
            UNSOLVED SIDEQUEST (1) :: PWRIN_REF PD has a ~120 Hz oscillation on it.
        . R_B2 migrated.
        . Aligned beam through holes 98 and 99, repeating process above.
            UNSOLVED SIDEQUEST (2) :: Now, with D_FBR_PWRIN_REF so far away, the known issue with its PD seating within the generic enclosure means the PD reflected beam is ~2 inches above the board. Tried a huge 2"x3" dump but that was too big.
        . R_B3 migrated.
        . With nothing to align, just checked that beam went through irises in holes 100 and 97, and that beam looked well centered on PD. They did.
        . Migrated D_IFO_REF_B and D_IFO_REF_A, confirmed PD reflection landed on there and it did.

Done for the day! The MEAS PATH alignment tomorrow!

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.