TITLE: 04/24 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

CDS Frame Write restarts @ 15:21 UTC

Lots BSC2 work was done today.
Beam splitter Stays were removed and in between BSC2 and HAM4. Pictures of the Beam Splitter cover and more details can be found here: alog link. 
The Beam splitter cartridge is closer than ever to fly out of the BSC2 Chamber. 

LOG:

Ibrahim, Jim, Mitchell

Mitchell and I removed the BS stays from the beamsplitter and placed them in the tube between BSC2 and HAM4. Then, Mitchell and I put the cover over the BS.

Jim and Mitchell were working on removing and bundling SEI cables from inside BSC2 for storage by ISI. Jim (on ISI) and I (in BSC2) then removed cable clamps from the bottom of the ISI/ceiling of BSC2.

Picture provided.

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

With help from Evan and Kevin I've been trying to understand how to make estimates of actuation strength for thermal actuators.  

In looking at data from the HWS, the values are divided by 2 to account for double passing (the compensation plates, ITM substrate, and SR3 are all double passed by the HWS beam).  

If we are using these values to calculate the focal length of a lens, we would use:

f_new = 1/(1/f_original +diopters)

If we are using it to calculate the ROC of a mirror, we would use :

Rc_new = 2/(2/Rc_original + diopters)   For SR3 we would use the 2.375uD/W number multiplied by SR3 requested heater power.  

Yesterday Randy and I removed the 4 Keel mass stacks from BSC2. A swivel lifting eye was used to gently lift until the mass stack seperated from the viton pads. Once seperated the viton was placed in a foil pouch. Each stack was wrapped in foil and craned onto a pallet. The last stack was wrapped with the pouch of viton. The swivel lifting eye was bagged and placed on top of the pallet of masses for use when the masses get added back onto the ISI.

The lifting pads, bumax hardware, and lifting fixture hardware plus SEI tools are staged on the table below the stairs to the garb room.

WP13189

Camilla removed the bellows yesterday (alog89994), so Randy and I moved the IOT2(ISCT2) table away from HAM2 and over closer to HAM3 on the +X side of the garb room there. This seemed like the most out of the way place while thinking ahead with door moves. The markings on the floor from 3/25 were still relevant, so I didn't mark anything new. Table height is marked with a label on the table, and again still relevant so I didn't change anything.

I then fixed up the curtains and turned the cleanroom on. Counts were below 100 right then, so it's looking good so far.

Per WP 13204 we added fw2 channels to the edc to save some frame writing information for the review of the new frame writer.

The usuall process was used:

1. regenerate the edc ini file

2. restart daq1 leg

3. restart the edc

4. restart daq0 leg

The daq1 leg was restarted around 8:20am localtime, followed by the edc.

The daq0 leg was restarted around 8:27am localtime.

There have been two restarts of h1daqfw0 since then, at 8:32 and 8:37.  Logs show that it was due to missing a input cycle (8:32) and running out of buffers in the circular buffer (8:37).  It as come back and appears to be stable now.

TITLE: 04/24 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: MAINTENANCE
    Wind: 9mph Gusts, 5mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.14 μm/s 
QUICK SUMMARY:
H1's corner station is still still vented for Beam splitter upgrades. Lots of activities in BSC1 & 2 chamber.

Potential work today:
More prep work for flying out the BS cartridge. 
SEI - HEPI CS pump station troubelshoot (Jim)?
Reconnect IOT1 (Tony, Camilla, Jennie, Fil cable?)  this table is back in place and bellows are in place.
End Station HWS work (Camilla, Maddi, TJ)
CDS/EE - LVEA, MER cabling for HAM6 A+,  work at SUS-M2, SEI-M1, and SUS-R7. [HAM7 sus to SAFE]
BSC2 - Drop Elliptical Baffles  <-( I think this is done already) 
VAC - CP1 Regen, lots of activity at Y-Manifold in LVEA, a few weeks

WP13189 Removed bellows from IOT2L. Guillotines and yellow covers are in place.

Madi, Camilla

This week we went down to EX and installed the OzOptics fibre pig-tailed 532nm 5mW laser, and co-aligned it with the HWS 532nm LED beam.
Out-of-fibre the laser power was 4mW, and after the PBS the power was ~1mW (compare to HWS LED at the same location, power was ~1uW)
The green laser return beam was visible at the HWS camera, with ~50uW power. It was also quite large, and the beam shape indicated clipping.
We took an image of the beam spots with the HWS camera, and also briefly installed a CMOS camera to observe the return beam. We cannot fit the entire beam onto the camera sensor, however you can see enough to observe striations in the beam profile (see attached).
Planning to calculate what lens to put in the path to ensure the beam is correctly sized for the entire path to avoid clipping.

Jennie W, Jeff Kissel,

Summary: Can we see a difference in jitter with JAC in the IMC ASC sensors? Short answer, yes.

The IMC has less angular motion with JAC installed at some frequencies - jitter is being suppressed by the JAC so less input beam motion relative to the cavity axis. The QPD readouts are noisier with JAC but there is one new suspension between JAC and the IMC so maybe the beam pointing to MC1 is noisier? MC2 TRANS QPD looks pretty similar with and without JAC, but this makes sense as cavity axis is still well aligned to this QPD. I need some other figure of merit to look at jitter as it only limits the IFO above 20 Hz, see alog #86555 by Sheila.

Since there was no time for a full IFO lock betwen the HAM1 vent and the current vent of the corner volume, we cannot directly check whether the jitter coupling to DARM is better with the JAC cavity.

We have lots of data of the JAC and IMC locked after the installation of JAC, however.

So I compared two times when we had roughly 2W input from the PSL to HAM1. In both cases H1 and the corner were at vacuum to rule out confounding effects from purge air and other sound noise seen when HAM1 was at air.

In both these cases the IMC was locked.

The two times I used were:

2025/11/17 15:38:54 UTC no JAC, during O4c

2026/03/20 00:26:01 UTC JAC installed, HAM1 at vacuum

Here is the ASD measurements for five sensors in the pitch degree of freedom:

IMC REFL WFS A  Roughly the same above 10Hz with and without JAC. Better with JAC between 0.3 and 7Hz.

IMC REFL WFS B Roughly the same above 10Hz with and without JAC. Better with JAC below 7Hz.

IMC REFL QPD A has lower noise now below 5Hz than before JAC installation and much higher noise at frequencies above 10Hz.

IMC REFL QPD B has lower noise now below 3Hz than before JAC installation and much higher noise at frequencies above 10Hz.

MC2 TRANS QPD roughly the same with and without JAC.

Jitter noise is more of a problem in the 20-800 Hz region, which these plots don't tell us much about.

I also need the check YAW

BSC6 annulus ion pump railed about 20 minutes ago, there appears to be a little communication to the main vacuum volume noted on PT410B, however it may just be electrical noise due to the change reported by PT410B, very small, its changes it is not replicated by other gauges, like PT424B.  Nothing to do about it right now, but we will check the annulus system ASAP.

M. Todd, S. Muusse, C. Compton, S. Dwyer

I wanted to get another measurement of what the HWS think the coupling factor is for thermal lens from ring heater power.

The HWS were not on, so after filling out a work permit Camilla and I went out and turned on the HWS SLEDs. Then we restarted the HWS codes in the individual computers. We also asked Jim to take ITMY ISI to fully isolated.

After waiting about 25 minutes for the HWS to get a baseline reading we turned up both ITMY and ITMX ring heaters by 4W (2W/segment). The HWS will track the defocus and I will compare with my models tomorrow morning. I wanted to do both ITM ring heaters to get a self-consistent measurement.

We also plan on doing single bounce OMC scans tomorrow morning with the ITMs being sufficiently thermalized after the RH turn on. This should give us another lens (punny pun here) to look at the thermalization business.

M. Todd, S. Dwyer, J. Driggers

Summary

We turned on inverse ring heater filters to speed up the heating for those (using nominal values for the settings). Because of the weekend mayhem with the earthquakes we did not get a SUPER long HWS transient measuring the full response, but we could get a pretty good estimate of the ring heater effect on the substrate thermal lens without any other heating in the measurement. This is good to compare to modeled values that we have.

I also turned on SR3 heater on Sunday to get estimates of the coupling of SR3 heating to the defocus of SR3. To do this, Jenne helped me untrip a lot of the SU watchdogs for the relevant optics to the HWS. About 3 hours after the SR3 was turned on the watchdogs must have tripped again and misaligned the optics. But fortunately we got the cooldown data for this as well and it's all pretty consistent. These measurement suggest a 4.7 uD/W coupling for SR3 heating, which is very similar to modeled coupling from Gouy phase measurements at different SR3 heater powers.

Overall, while these measurements provide more pieces to the puzzle, they make previous analyses a bit more confusing, requiring some more thought (as usual).

WP 10894. Over the break we had 24hour CO2 tests with both annular and central masks to understand time constants effecting our circulating power transient alog 66548.

Attaching plots. CO2X Annular 4.7W, Central 3.0W. CO2Y Annular 4.2W, Central 3.3W. 

Some interesting things:

• For the spherical power measured by HWS to stabilize with it take 30 minutes annular heat but >2hours with central heat!
• The LSRPWR_MTR measured power changes by ~1% over 2-3 hours after turn on. See plots. Dan Brown noticed this and suggested it could be caused by something on the CO2 table (maybe the masks) warming up. This effect would be too small to cause any IFO power up trnaiset we see.
• Plot attached comparaing these CO2 tests to ITM oplevs and L2 and M0 witness channels. You can see a small effect on the ITMs when the CO2s are turned on. ITMY L2 witness moves 1-2urad over the 24 test in the oposite way of the natural drift (pink and grey plots). ITMX L2 witness cannot be trusted at this time.