We ran the OPLEV charge measurements this afternoon. We had a env / package issue trying to start the script, it was complaining about the scipy sin function, I ended up changing from the default cds env to the aligoNB using "conda activate aligoNB" after doing a pip env search to find which environment had the needed packages, I still had scipy sin issues but they were depreciation warnings. To fix this script we may be to rewrite the scipy parts with numpy. The End Stations SEI configuration was ISI_DAMPED_HEPI_OFFLINE. This was a pretty good measurement unlike a few of the previous ones, I didn't get any saturations on either QUAD and the coherence was pretty good.

ETMY's charge is a little high (above 50 on half of the plots) but it is trending to zero or is mostly static near zero (UR P).

ETMX's charge is high (above 50 on all but 2/8 plots but not quite at 100) and is trending away from zero, increasing. The ETMX_L3_LOCK_BIAS_OFFSET value has been at its "unlocked" value of -8.9 during the break, it flips to ~+6 when we are in full lock.

We are still fully processing and thinking about the results, more to come.

In order to clear up the incoming file changes on 22 nodes and to satisfy the quarterly reboot FAMIS, I rebooted the machine 13:30PT. All 176 nodes came back on their own. Me, Corey, and Ryan C cleaned up the requested states for suspensions and other various nodes and brought SEI HAM1,2,3 and BSC2,3 chamber managers to ISI_DAMPED_HEPI_OFFLINE, IMC_LOCK to Offline, ISC_LOCK to Idle. 

Tue Apr 07 10:10:57 2026 INFO: Fill completed in 10min 53secs

Erik is powering down the h1seih7 system to continue our recovery work. First up: replace the timing card to see if we can get the 16bit-DAC operational again.

TITLE: 04/07 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: 5mph Gusts, 3mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.15 μm/s 
QUICK SUMMARY:

Things on the menu for today, HAM1's +y door, venting the corner, and a lot of prep (HAM3 doors should also be coming off this week & more prep for BBSS work!). 

h1seih7 is still down (so HAM7 SEI & SUS systems are all red). 

The Ops Overview also continues to have "IMC INPUT POWER" flashing from 0-200W (but I was assured this was not real and purely a calculation error; light pipes have been closed since last Fri morning).

OPS Note:  I will leave the con around 1045amPDT for a tour and then to attend a BBSS preparation meeting at 1pm PDT and RyanC has graciously offered to cover for me.

WP13100 Add 3 ADC to h1seih7 for h1susauxh6

Marc, Jeff, Corey, Jim, EJ, Erik, Dave:

After being tested on the DTS, 3 ADCs were added to h1seih7 for HAM6 SUSAUX. We took the opportunity to upgrade the firmware on the timing card and replace its sync-ribbon.

After the upgrade the single 16bit-DAC on this system ran immediately into a FIFO-EMPTY state and the IOP has a permanent DAC status. We verified the card and cable seating, all good but no change. We removed the 3 new ADCs, no change. We removed the 3 new ADC Interface cards, no change.

At this point we ran out of time, Jim said it was OK to leave HAM7 SEI down for the night. We will try timing card and DAC swapouts Tuesday.

WP13115 Reduce susb13 SWWD trip times

Jeff, Corey, Dave:

I installed a modified h1iopsusb13 which reduced the total SWWD SUS trip times for the ITMs from 20 mins to 15 mins ( from 5+15 to 5+10).  All models on h1susb13 were restarted, no DAQ restart was needed.

WP13132 Add ADC to h1susb2h34

Marc, Erik, Jeff, Corey, EJ, Dave:

After being tested on the DTS, an additional ADC was added to the h1susb2h34 IO Chassis. The timing card sync-ribbon was also replaced.

The h1iopsusb2h34 model was modifed to add the ADC. A DAQ restart is needed (pending).

WP13133 Add ADC to h1susauxb2h34

Marc, Erik, Jeff, EJ, Dave:

After being tested on the DTS, an additional ADC was added to the h1susauxb2h34 IO Chassis. The timing card sync-ribbon was also replaced.

The h1iopsusauxb2h34 model was modifed to add the ADC. A DAQ restart is needed (pending).

No DAQ Restart Was Done

Due to the h1seih7 issues we did not restart the DAQ on Monday. This means we have bad DAQ data for the models:

h1iopsusb2h34, h1iopsusauxb2h34, h1spih23.

Tuesday we will fix the h1seih7 issue, then restart the DAQ to resync INI for the two B2H34 models and add the new models h1spih23, h1suslo12, h1susauxh6.

Workstations were updated and rebooted.  This was an os packages update.  Conda packages were not updated.

TITLE: 04/06 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

GV2 was hard closed, one of HAM1's doors (-y) was installed (+y tomorrow). 

Suite of CDS tasks were started in the afternoon (had issues with restoring SEIH7).

Please Ignore:  "IMC INPUT POWER" Ops Overview  (Jennie mentioned the calculation is not correct on this medm.)

LOG:

• 1454 PSL power taken from 10W to 0W
  • 1458 IMC to OFFLINE
• 1513-1533 lvea prep for the week's activities (randy)
• 1550 CEBEX contractor on back-side of Y-arm to dig down to water line to get size of pipe (bubba)
• 1626-1650 MY to get info on genie lift batteries (chris)
• 1630-1750 looking for fil in lvea(marc)
• 1637-1655 tour for the new fellow (Madi) & put parts away (jennie)
• 1642-1827 unlocking HAM1 ISI (jim,tony)
  • 1738 unlocked, jim running TFs, & tony OUT
  • 2334 took HAM1 to ISI_DAMPED_HEPI_OFFLINE
• 1657-1715 Putting totes (betsy,mitch)
• 1703-1713 Grabbing dustmonitor in pcal lab (ryanC)
• 17041825 More lvea prep work (randy)
• 1720-1823 Hard Close gv2 & Filter Cavity gate valves (gerardo)
• 1729-1735 checking SPI cabling at CER & HAM3 (marc)
• 1759-1811 Tour (dolly)
• 1817 Checking TCS tables (camilla.madi)
• 1819-1829 cable checks (marc)
• 1859-1912 spi cabling at cer + lvea (jeff, fil)
• 1900 Locking up HAM3 HEPI (jim)
  • 1900 HAM3 taken to ISI_OFFLINE_HEPI_ON
  • 1913 SEI_HAM3 taken to OFFLINE (jim)
• 1946-2000 HAM1 door prep (randy)
• 2004-2320 SPI & bsc2 in-rack cabling at cer (fil)
• 1935-2010 installing cables in SEI-C1 rack 
• 2015-2235 HAM1 door (randy, travis, gerardo)
  • 2024 travis joining, 2029 gerardo joining
  • -Y HAM1 door was installed.  Then the cleanroom was moved so the +Y HAM1 door can be installed tomorrow.
• 2030-2150 CHeTA viewport inspection in optics lab (camilla, madi)
• 2043-2050 lvea walkabout:  bsc platforms, laydown areas (betsy)
  • 2150-2233 Another trip to lvea; also had group move a cleanroom (betsy and crew)
• 2047 cds model (susb13, sei7) work  (jeff.dave.oli, erik)
  • 2115 Erik & marc heading out to the floor to install new boards
  • 2206 taking down seih7
    • After this was brought back, had issues with the daq (could not ISOLARE HAM7).  Erik's doing a power cycle of the crate, but still have the issue; looks like they have found a bug.  Working on a workaround at the moment 
• 2117 STS wiring in cer (jim)

Randy has been hard at work adding temp handrails and the eMod garbing cleanroom to the BSC2 platform access area.  Its pretty workable now.  The temp handrails have a pretty large footprint so I might make changes to those in the next incarnation of this, so the walkway from the eMod to the BSC2 platform is pretty narrow.  This platform and eMod placement will service BSC1 and BSC3 as well however, so we will rework or remove some handrails as we add those sections.  The tent is easy to pull back when we need the dome and cartridge to be craned away.

Now that HAM1 is closing again (doors going on with VAC team now), we are turning attentions back to the CDS and BBSS work slated in line next.  Attached is the snapshot of the Trello with the next vent actions queued up.  We anticipate venting the corner chamber volume and also opening HAM3 this week.

FAMIS 31132

The broken anteroom fan was swapped last Wednesday, so there are changes seen on several trends at that time. The ISS diffracted power increased, so I've just adjusted the RefSignal slightly to bring the diffracted power back down to around 4% and the PMC transmission back up to what it was before the fan swap.

Mon Apr 06 10:07:21 2026 INFO: Fill completed in 7min 18secs

Hi everyone it's been a while since I posted!

Julia Rice and I had a chat with Peter F today about motivating the electrostatic violin mode damper we've been building at Syracuse. We came away with a couple of questions to answer:

1. What's the actual displacement of the fibers when the violin modes are excited, and is our shadow sensor noise low enough to measure the modes.

2. What is the origin of the two violin modes per fiber? Is it fiber ellipticity built into the fibers themselves or asymmetry their attachment points AKA the ear/horn. If it's the former, we'd expect the main oscillation axis of the modes to be randomly oriented. If it's the latter we'd expect 4 modes per test mass to be dominant in DARM, and 4 modes to be much weaker, we'd also perhaps expect to see a regular spacing between pairs of modes.

I still have remote access (thanks Dave for helping me get my ports sorted with NoMachine), so I logged in to grab some plots of violin modes excited vs damped times.

I found an excited time and a quiet time by plotting the ISC_LOCK guardian state and the monitor for ITMY MODE5 which I know is a problematic mode (first plot). I used 5 November 2025 17:59:09 UTC, gps 1447264767 for the modes excited time since this was after many locking attempts with the mode5 monitor was ~20k counts. I used 17 November 2025 20:57:12 UTC, GPS 1447448250 as my quiet time AKA t=0 on the first plot.

Second plot is the money plot! When the modes are excited their amplitudes in DARM range between 1e-16m/rt(Hz) and 1e-14m/rt(Hz), we can roughly convert this to fiber displacement by multiplying by the fiber to test mass mass ratio. We did some back of the envelope calculations with Stefan and there's a factor of 2pi in there somewhere too.

I labelled the plot referencing this handy violin mode spreadsheet from Rahul et al, which set me thinking about the violin mode origin in question 2 above...

I can see the regular spacing with one large mode and one smaller mode in the ETMs for the excited spectrum. BUT it's not like there is 4 modes visible in DARM and 4 that are totally anti-aligned: the smaller modes are still very much visible in the DARM spectrum.

ETMX9 (516.781 Hz) has a small buddy ETMX7 (516.678)
ETMX1 (511.2993 Hz) had a small buddy ETMX6 (511.18)
ETMX3 (508.938 Hz) has a small buddy ETMX4 (508.844)
ETMX8 (507.36) has a small buddy ETMX2 (507.493)

For the first 3 pairs, the bigmode is higher in frequency, not sure if significant. Also, in the damped spectrum the larger modes can become sufficiently damped that the smaller mode is now louder in DARM, I wonder if that might be because we have spent many more hours tuning and damping the settings for the large modes?

There are also some modes that break the trend: ETMY1 and ETMY6 are very close together.

For the ITMs, things are less clear. ITMY1 and ITMY2 are similar height in DARM, same with ITMX8 and ITMX7, and ITMX3 and ITMX5. Things are confusing around the clusters of modes 504 Hz and 508 Hz.

I had previously always assumed that ITMY mode5 and mode6, the extremely close modes, are on the same fiber. But perhaps mode5 is on the same fiber as mode7, and mode6 is on the same fiber as mode8!

To better visualise the data, I made a table of the mode "buddies" and their frequency separations here, check it out if your interested. There is a goofy plot in there with no x-axis and mode spacing on the y-axis. The frequency spacing of pairs of modes is centered around 0.1Hz.

I do think there is scientific value to having a shadow sensor at the fiber: it's clear that the modes are not perfectly aligned or anti-aligned with the DARM axis, I was able to identify all 32 modes. In the egregious case of ITMY, at least 7 of the 8 modes are large in DARM. That being said, the regularity of the spacing means I am quite confident (for most modes!) which two modes are on the same fiber.

Please let me know if I've missed something or if you have any thoughts!