Lockloss at 2025-06-25 21:45 UTC probably from the wind. Three seconds before the lockloss, we had an EX saturation. Wind jumped up all of a sudden, peakmon jumped up (although from very low to still pretty low but LSC CPSFF was affected), DARM had a bit oscillation, and almost all the ASC channels rang up starting 20-25 seconds before the lockloss

FAMIS 26395, last checked in alog85021

All fans look largely unchanged compared to last week and are all within noise thresholds.

Closes FAMIS26392

For the CS fans, they look fine althought MR_FAN5_170_2 is a bit noisy.

For the OUT building fans, there's a periodic noise increase on a few different fans. EY_FAN2_470_2, EX_FAN1_570_{1,2} and MX_FAN2_370_1.

Kiet, Robert, and Carlos

We report the results of calibrating the LEMI magnetometers in the Vault outside of the X arm; 

We went out on May 15th, 2025 and took the following measurement with each lasted 2 minutes.
Far field injection: to calibrate the LEMI 

1) 17:36:45 UTC; X-axis far-field injection; without preamp on the Bartington 

2) 17:43:23 UTC; X-axis far-field injection; without preamp on the Bartington 

3) 18:01:53 UTC, X-axis far-field injection; without preamp on the Bartington 

4) 18:04:15 UTC, X-axis far-field injection; without preamp on the Bartington 

5) 18:23:25 UTC; Y-axis far-field injection; with preamp on the Bartington 

6) 18:26:00 UTC; Y-axis far-field injection; with preamp on the Bartington 

The preamp gain is 20; all injections are done at 20Hz. The coil used for far field injection has 26 turns, 3.2 Ohms.

The voltage that was used to drive the injection coil for farfield injection: Vp-p: 13.2 +- 0.1V. It was windy out so we decided to use the preamp on the Bartington magnetometer.
The LEMI channels used for this analysis: H1:PEM-VAULT_MAG_1030X195Y_COIL_X_DQ; H1:PEM-VAULT_MAG_1030X195Y_COIL_Y_DQ

Bartington calibration

7) 18:49:38 UTC; with preamp on the Bartington 

8) 18:52:50 UTC;  with preamp on the Bartington 
the voltage that was used to drive the injection coil for farfield injection: Vp-p: 1.88V +- 0.01V 
We inserted the bartington magnetometer to the center of a cylindrical coil to calibrate its z axis(1000 Ohms, 55 turns in 0.087 m) 

The final results of LEMI calibration after taken accound the all the measurements is (9.101 +- 0.210)*10^-13 Tesla/counts, there is a 20% difference between this measurement and the measurement taken pre O3. Robert noted that when taking the previous measurements, the calibrating magnetometer was not fully isolated from the LEMI. This time they are completely independent.

We recommend analyses that use LEMI data to use the calibration value of  9.101 * 10^-13 +- 5% Tesla/counts to be consersative.  

For FAMIS #26389:  All looks well for the last week for all site HVAC fans (see attached trends).

Closes FAMIS 26386 and FAMIS 26384 and FAMIS . Last checked in alog 84405,

Everything is under threshold. Took 2 weeks since was undone for the week prior.

Camilla, TJ

I went to turn on the CO2 lasers to prep for locking today. I found both power supplies on the mechanical room mezzanine needed to have their outputs turned on. For TCSX, I then was able to turn the controller on, turn the key, hit the gate button, then turn on the laser via medm as usual. For TCSY though, the controller complained of a Flow Alarm as soon as the unit was turned on, and turning the key or hitting the gate would not clear it. The flow was reading 2.45gpm according to the paddle wheel flow meter on the floor, and before the vent we were just above 2.5gpm on the floor and 3.4gpm at the chiller. We had reduced the flow of this chiller back in December with Robert (alog81246), so I tried bumping up the flow slightly to 2.6gpm on the floor in the hopes to clear the flow alarm. Now, the flow alarm wasn't present when turning the unit on, but then when I turned the key and hit the gate button, the flow alarm came back.

At this point Camilla and I checked cable connections, tried turning the chassis off and on while waiting a bit, patting our heads while rubbing our bellies, and some other non-fruitful things. Eventually we moved the flow back up to 3.8gpm at the chiller and 2.8gpm at the floor and the flow alarm never showed up. We tried to bring the flow down a bit, but the flow alarm would return. We have no idea why the controller isn't happy with us running the flow at levels that we have been for all of 2025. For now, sorry Crab Nebula.

(CoreyG, MitchR, RandyT)

Wind Fence News

Today Location #4 (of6) had fabric panel started it was attached above the middle (so, 3 of 5 horizontal cables were secured to this panel).  The panel was then secured at this stage since the afternoon winds were beginning to pick up.  

At this point we moved to location #5 (of 6) and continued attaching the big/thick horizontal cables (bottom was installed last week, so the remaining 4 were tensioned-up/installed.  

Bee News

After this work was done, several NEW bee swarms were observed along the X-arm as we drove back to the Corner!

(Earlier this week an X-arm bee swarm was observed and a bee person installed a bee hive box; this box seems to be getting populated, but we did see some bees continuing to go into the Beam Tube at this location). 

But today, we saw (3) NEW Swarms at the base of the Beam Tube Enclosure---their swarms appeared within 2hrs!  The bees are entering at the joint between the cement enclosures. Many of the joints have holes in the cauking toward the ground and this is where the swarms were centered; as we drove back to the corner several more of these holes had smaller groups of bees investigating these holes.  Mitch went to notify Richard about the situation when we got back to the Corner Station.

(CoreyG, MitchR, RandyT)

This morning, Randy watered down the sand roads.  Later, Mitch & Randy swapped in the new (& better) rigging hardware for the Wind Fence on all the big poles.  

This afternoon, 2 (of5) horizontal cables were installed at Location #4 (of 6).

And of course a new bee hive was observed.  This one is up in the Wind Fence vicinity, and is forming on....a tumbleweed!  Tyler was notified and he checked it out.

Next up is continuing to install horizontal cables at location #4, 5, & 6.  Then panel install and securing panels.

(CoreyG, MitchR, ChrisS, RandyT, JimW)

This week's wind fence work continues. With a couple of issues that continued from last week and were addressed:

1. Soft Sand-- This has been an issue because it is fairly easy to get aerial lift wheels stuck in the sand.  Because of this, and since the big rental aerial lift was in position near the 1st panel (or "southernmost panel"), it was decided to do this panel's rework in one shot (vs the usual procedure of doing a step for all panel positions, and then moving to next steps for all positions, and so on)
2. Bee Hive--Last Thursday, a beehive swarmed the wooden spool for the large wire.  A beekeeper was phoned in to help rehome this hive.  A beehive box was placed near the spool and today, this box was moved so the spool could be reinstalled in the trailer for use.

The first panel is mostly complete (on Tues) with one vertical cable remaining to be installed.  Old panels had thinner cables removed and are folded up for future availability and storage.

A water tank was delivered to EX (Tues) to allow daily soaks of the sand to help improve travel.

Today (Wed) was a windy day with sustained winds of around 15mph, so this morning mostly focused on non-at-height work.  The thick cables were cut for the remaining 3-panel locations

(CoreyG, MitchR, RandyT, JimW)

Previous work posted here.

Today started with Randy and Mitch getting the small green tractor to EX and then working on compacting some of the very soft sand around the wind fence (on the front side of the Wind Fence---closest to EX).

Started to remove the final 3-wind fende panels (of 6 total).  While driving the orange rental manlift (on the backside of the wind fence), it managed to get dug in some pretty deep sand a few times.  On the last dig-in, we kept the manlift here (dug out/compacted sand around it and focused work on the furthest away wind fence panel since we already had the orange manlift here).  The plan is to do everything for this panel location all at once:

1. Remove old (crappy) hardware,
2. Install better hardware,
3. Clamp horizontal wires to the end/furthest pole,
4. Start tensioning the 5-horizontal wires into place
5. Install new wind fence panel

Today we made it to step 4 and did the 1st/bottom horizontal wire.  

We ran out of the thick wire, so the trailer was brought back to the Corner Station so the 1200lb spool can be loaded into the trailer in the morning.  Then will continue getting that 1-panel installed....and then work on getting the orange manlift unstuck.

Debasmita, Preeti, Gaby

Robert did some injections at 0.2 Hz in the BS HEPI which showed a slight increase in DARM. We wanted to check further if the microseismic ground motion (0.1-1.0 Hz) is creating any noise in LHO as it does in LLO. For this, we chose the glitches in DARM picked up by omicron, having frequency in the range 10-60 Hz and SNR in the range 5-20.

• The first image shows the variation of glitch rate and the microseismic ground motion during December 2024. It looks like the glitch rate was higher on the days when the microseismic ground motion was high. 
• The second image shows a scatter plot of glitch rate vs ground motion and from this we can see a correlation between the two. 
• We calculated the Pearson and Spearman correlation coefficients between the glitch rate and the microseismic ground motion in two frequency bands 0.1-0.3 Hz and 0.3-1.0 Hz. The correlation values are tabulated below. Ground motion in both the bands show good correlation with the glitch rate. But, the ground motion in 0.1-0.3 Hz is better correlated with the glitch rate. 

• The third image shows the frequency and SNR distribution of the glitches that we chose. There are a total of 11111 glitches. 
• The fourth image compares DARM spectra during a quiet time and a time of high microseismic ground motion and there are some excess noise visible during the latter.  

The attached pdf shows qscans of some of the glitches chosen from high microseismic days. It is not very clear from the qscans if the glitches have arch like morphology, which is usually the case for glitches caused by scattered light. But, some of the glitches do show repetition within short time interval which make us suspect if they are produced by scattered light. We are still working on this to figure out if it is the process of scattering which is upconverting the low frequency ground motion to create noise in the 10-60 Hz band.

In summary, it looks like the microseismic ground motion is affecting the DARM sensitivity at LHO, maybe not as much as it does at LLO.

TITLE: 05/06 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: 9mph Gusts, 5mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.11 μm/s
QUICK SUMMARY: Vent work continues today with more HAM1 alignment and wind fence work.

(CoreyG, MitchR, RandyT, JimW)

Attached photo files have names describing them and they are mostly in order of when they were taken (except for the first 4, which are "overall highlights").

EY Wind Fence Status:  COMPLETED on May2nd

This work started the week of April 28th.  The wind fences overall have been in need of a reconfiguration to UNDO what the contractors did to build them--> Because they were not great in high winds and had frequent failures during wind storms.  The EY Wind Fence was the first structure to get it's panels removed, hardware reconfigured/FIXED, and panels reinstalled.  However, the final ("left-most" panel did NOT get the upgrade and had failures in the last year).  This last panel needed its upgrade and this is what started the week of April 28th.  By the end of the week, this final panel received its upgrade and the EY Wind Fence was complete.

The upgrade was basically removing alot of the original rigging equipment holding the fabric fence panel and replace it with more rigging hardware.

EX Wind Fence Status:  Started today on May 5th

The first job here was driving (2) manlifts from EY to EX (this took about 90min and a 1/4-tank of gas for each).  Then there was a bit of prep work and gaming out where to start.

The EX Wind Fence was with the original equipment, so the entire EX Fence (6-panels) needed upgrade work.  Three panels for the EX Wind Fence were removed, but while trying to get to the 4th panel the smaller (blue) manlift got stuck in very soft sand.  At this point, this work paused to reasses a way forward (Also phoned Tyler to take a look at the situation.).  

The plan now is to get the small green tractor down to EX and try to compact the sandy ground as best as possible.  It's not clear if this will work, but this is where we currently stand.  

Closes FAMIS 26375. Last checked in alog 84000,

Everything is under threshold. There are different fans on than last week so difficult to compare. MR FAN3 in CS has a slightly higher noise character in last 3 days

FAMIS 26374
The Vibrometers for the HVAC fans look ok , no interesng feates really stand out.

Closes FAMIS26372, last checked in alog83723.

Nothing of note on the scopes, everything looks like it did during the last check.

Following on Oli's discovery that the MX wind speed was zero for many hours Tue night/Wed morning, it appears that the MX anemometer sticks when the wind speed is below 5mph. The attached plot shows MX (red) and EX (blue) wind speed comparison.

I noticed the same thing when observing MX anemometer from the road side, it look a good gust of wind before it got moving. Tagging PEM.

Closes FAMIS 26371. Last checked in alog 83630,

Everything is under threshold. H0:VAC-MX fans had a sudden increase in noise character and signal 6 days ago.

For FAMIS #26369:  All looks well for the last week for all site HVAC fans (see attached trends).