Robert, Dave:

h1pemex was changed, the newly installed AMON subsystem which reads the current to ground signal now drives the 4th channel of the 20bit-DAC via the GDS_3/DACOUTF_3 filter module chain.

h1pemey was modified to fix a typo I had made to the DACOUTF_3 filtermodules, it was missing the underscore.

Both models were restarted at 15:55, followed by a DAQ restart at 16:01-16:06

I created MEDMs for the new DAC drive system. I'll work with Ryan S on integrating this with his "GDS DAC DRIVE" screen, currently I've added buttons to the bottom of Ryan's MEDM to open mine.

TITLE: 02/13 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 3mph Gusts, 2mph 3min avg
    Primary useism: 0.07 μm/s
    Secondary useism: 0.59 μm/s 
QUICK SUMMARY: Another cold and foggy morning at LHO. Today, the EOM with its new crystal will continue to be aligned in HAM1 while the JAC reflected path is finalized pointing to IOT1. HAM7 continues to pump down as well.

TITLE: 02/12 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Dave did some CDS restarts early in the day, alog89133, and alog89130 and again at the end of the day. Secondary microseism has gone up quite a lot in the past 9 hours, presumably from the 10.5m (windy.com) waves crashing into the Juneau/Ketchikan area north of Washington state. VAC team left an AUX cart pumping down by HAM4. HAM1 alignment and EOM crystal work continued today.
LOG:                                                                                                                                                                                                  

Jennie W, Jason O, Keita K, Betsy W, Camilla C

Summary: EOM alignment and position captured, moved to opics lab for crystal replacment, JAC-REFL path alignment in progress.

This morning Jason, Keita and I checked the centering of the HAM1 irises after the JM3 alignment Olli and I did on Tuesday. We didn't move the irises right after JM3 as this seemed centred. We did reposition the iris right before the HAM2 septum plate in x and y.

This, along with the alignment of the IMC Olli, Jenne and I did on Tuesday, captures where the beam was with the current EOM installed.

Keita marked the EOM base position with a dog clamp and removed it to the optics lab for crystal replacement. The shims for the EOM and the screws that hold it to the table are in a foil packet on the +Y - X HEPI pier.

Betsy, Camilla and I rechecked the REFL path and spent some time moving JACR-M2 to centre it on the incoming and outgoing beams. Then we pitched down this mirror so the outgoing beam hit the upper periscope mirror. After this Betsy had some concerns that we were too close to where the JM3 tip-tilt will sit (we are  currently using a siskiyou mount for this mirror). So we yawed the JACR-M2 mirror so the beam hits the viewport slighly more to the right (as viewed from -Y side). Looking at the placement on the viewport simulator, the beam is low and right on the viewport, whereas it comes to the table, high and right in the bellows hole. This table it almost at the top of its adjustment range, so Jason and I plan to go in this afternoon and see it we can move up the table feet so the beam can move up in the viewport a bit. Betsy and I measured the tilt of the beaM from JACR_M2 off the table. The heigh is 103 mm at the table hole 8 inches from the -X edge and 8 inches from the +Y edge. It tilts up to 113mm at the last hole in this row on the -Y side.

Betsy and I also checked the pitch of the beam entering and leaving JAC after the EOM was removed. The input beam to the JAC was 102 mm above the table, the output beam before the L1 lens was the same height, and the beam height just before JAC_M3 was also 102mm. There is not a large distance between the JAC and JAC_M3 steering mirror so it is hard to get a good measurement of any small pitch in the beam. Pictures for this alog are coming.

Jennie W, Jason O, Tony S, Olli P

Yesterday we put the viewport simulator on the -Y door of HAM1 to enable us to check the JAC REFL path, we had to move the in-vac mirrors for this path a couple weeks ago because the beam hit the side of a beam dump before hitting the second steering mirror after the JAC input coupler and so was mis-aligned.

The viewport simulator has tape marking the centre of the real viewport for this beam that was put in last time we had it up on this door.

We also rolled up the IOT1 table and plugged it in.

We had to move the table in -x direction from its ground markings as the periscope was too far right in the relative to the bellows hole and the viewport simulator, we also moved JACR-M1 as it was one row of holes too far in plus x direction.

The beam hit too high on the periscope, so it was missing the mirror by an inch, this will need to be corrected with pitch on the in-vac steering mirrors.

Closes FAMIS#39854, last checked alog88973.

For the CS:

MR_FAN4_170_1 had a slight noise increase a little over a day ago, MR_FAN2_170_{1,2} are both seeing lots of spikes.

For the OUT buildings.

The EX fans all increased in noise around 15:30 UTC this morning.

Today Randy T and I ran power for the Cross Flow HEPA fans on the platform around BSC2.  The fans are on and turned down to low at the moment.  We also moved the dust monitor from the floor to the platform to monitor dust counts to have a better understanding before pulling the dome.

Thu Feb 12 10:13:15 2026 INFO: Fill completed in 13min 11secs

Travis confirmed a good fill curbside. He removed an ice ball from the end of the discharge line pipe.

Dave, EJ, Ryan C.

Following the h1pemey install this morning I realized that this was the only model on h1iscey built against the latest RCG5.5.2 (all others were still at 5.5.0).

With Ryan's permission I rebuild h1iopiscey, h1iscey, h1caley, h1alsey with rev-lock to ensure identical software using RCG5.5.2 and restarted all the models at 09:41.

No DAQ restart was required.

WP13027, WP13029

Robert, Ryan C, Dave:

I installed new h1pem[cs, ex, ey] models this morning. Changes are:

 . OSC+NOISE_GEN signal-injection section for DAC drives

 . New AMON ground current monitor signals

 . Fix GDS_n indexing at end stations

Note that the temporary "ADC" channel names for the ground current monitor could not be removed because they are being sent by the DAQ Broadcaster to GDS. These should be either changed to the new names (and CS added), or they should be removed.

A DAQ restart was required. This generally went OK, but FW0 restarted itself after running about 8 minutes.

In the event MER in-rack work causes issues with h1sush7 SWWD, I have bypassed h1seih7 SWWD for the duration of the work.

The vane position of the fan inside air handler 1 at End X was changed from 100% to 70% in order to increase the airflow through the fan. This was changed to more closely match the settings at End Y. End Y temperature trending has been consistent while End X has had moderate variation in comparison. 

TITLE: 02/12 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 3mph Gusts, 1mph 3min avg
    Primary useism: 0.05 μm/s
    Secondary useism: 0.28 μm/s 
QUICK SUMMARY:

• HAM1 work continues today
• Lots of patches of thick fog around town and site

Following alog 89115, we found that the old batch crystal from that alog (S/N10252003) had a big chip at one corner. It is pretty bad we don't want to use that.

Betsy found another old batch (S/N10252007, "inspected 12/21/11" and UF tag dated 4/21/09), so we A-B-ed that one with the spare new batch (S/N B1913108).

The beam path was made as level as possible at 3" height using a beam leveling tool (a black metal thing with a tiny aperture at each inch of height).

We put the crystal on a platform that is roughly 2" 29/32 (which is about 2.4mm lower than 3"). The crystal is 4x4x40mm so that's about the right height.

We spent some time to make YAW alignment as good as we can for each of the crystals.

We scanned the beam in PIT from top to bottom (or bottom to top), each extreme is where the beam is almost clipped (but not actually clipped) by the top or the bottom face of the crystal.

Look at the attached, the new batch (left column) clearly shows multiple beams even though the focus is not as sharp as the old batch photos. As we misalign in PIT, the dark place moves relative to the main beam and the contrast changes too, but multiple ghost never went away. At the extrema (very close to the top or bottom edge) it looked as if the beam is better but I'm not sure it actually was.

The old batch (right) didn't show such a behavior. The beam shows something like a diffraction pattern but no separate ghost beams. Everything moved with the main beam.  Not sure if the diffraction pattern came from the aluminum surface or EOM, but clearly this is MUCH better than the new batch.

Note, due to the apparatus (the steering mirror is 20" upstream of the EOM), we haven't searched in a huge PIT angle space, it's actually roughly +-4mrad or so, the angle is not negligible but it's more parallel displacement scan than an angle scan.

Also note, when the crystal was put in place it seems that there's some vertical deflection which was different for the old and the new. On the top two pictures, there's no change in the input alignment into the crystal. 

Based on this observation, I'd say using the old batch makes sense. LHO people (Jennie, Rahul, Betsy and myself) had a brief conversation with Masayuki and MichaelL and we all agreed that that's the way to go.

Jennie W, Jason O, Keita K.

As reported in this alog (#89073) from Masayuki and Keita, after we turned the power in HAM1 up to 1W we found a series of vertically spread ghost beams aroubnd the main beam after the EOM and before JM3.

These could not be removed by translating, yawing or pitching the EOM position relative to the beam. It was decided in a larger meeting with EOM design personnel that we would first check if the crystal was cracked or damaged anywhere in case this is the cause.

First photo shows the EOM from above, using a green torch to illuminate the beam path. I can't see any scatter from defects or cracks in the crystal.

Second photo shows possibly a chip at the corner, but this should not affect the beam as its right at the edge.

Third and fourth show side view with illumination from the top at an angle.

In summary we did not see any 'smoking gun' to cause these ghost beams.

Randy, Ibrahim

Randy and I put the BBSS in the can today, as shown by pictures.

Following LLO's advice from their experiences in alog 79950, we were able to use the aluma lift to can the BBSS. What we did in order:

1. Strip locked-mass BBSS of all cables, check for looseness, bring alum-a-lift into position to lift BBSS from lifitng bars

2. Undo dog clamps to let lift take suspension load, ensure suspension is secured on the lift. Move BBSS out of test stand - as LLO said, very small clearance.

3. Prepare temporary platform for lift fork adjustment

4. Set BBSS on temporary platform - this part was successful but needed extra blocks to avoid interference with Y-bracks on the Lower Structure.

5. Adjust forks to be allow for canning without bottoming out, relift.

6. Put into wiped-down can and check for looseness. Rewipe, check for particulate and ensure secure fit

7. Close doors.

See pictures below.

(Jordan V., Gerardo M.)

-Late entry

On Friday we removed and replaced the ion pump for HAM3.  We replaced the copper gasket twice, the first gasket seal had a bad leak, it was hard to see the mating surfaces due to visibility issues (laser safety goggles and not enough light).
After installing a second gasket, we started pumping down the annulus system and pressure went down fast.  Last pressure reading at the aux-cart was 4.63x10^-05 Torr.
BTW, we have other 4 (four) ion pumps to replace.

On Sept 4th we had a longer commissioning period to allow us to heat up OM2.  The main goal was to use this to characterize the mode matching of the arm cavities to the OMC, but we also made some other interesting measurements.

Summary:  heating up OM2 now costs us about 1% of optical gain, while it used to cost us 2%.  Heating up OM2 also changed the SRCL offset needed to get flat squeezing significantly, and reduced the amount of squeezing that we could get (without adjusting psams).

The interferometer unlocked (86727) while Jennie Wright was running the DARM offset step script with OM2 cold, to get a measurement of HAM6 throughput and look at OMC refl before heating up OM2.  As that link says, there wasn't an obvious connection between the DARM offset script which was in it's final steps (nearly back to normal) when the lockloss happened. 

We turned on the OM2 heater while relocking after some back and forth, then had an commissioning caused lockloss while trying to recover.  By the time we were relocked, OM2 was heated up according to thermistor 2, which is the thermistor who's timescale matched the timescale of optical gain changes in the past (see screenshot of June 2023 example).  We also had a large earthquake while relocking, so we paused after power up and before going to nominal low noise, so we do not have tracking of the optical gain using pcal in the first 30 minutes of this thermalization. 

The optical gain in this thermalization seemed to be fairly similar to the previous lock where OM2 was cold in the first hour.  The change in optical gain between OM2 hot and cold was much smaller this time around, so we needed to see the full thermalization in order to see what the gain change was.  We set the OM2 heater off 4 hours and 5 minutes after the power up, the attached screenshot shows a trend of optical gain during the previous thermalization while OM2 was cold, with a vertical cursor 4 hours 5 minutes into the lock.  The horizontal cursors show where the optical gain was at 4 hours and once the thermalization was complete, the optical gain continued to increase by 0.2% after the first 4 hours. The next screenshot shows vertical cursors also at the time of power up and 4 hours later, and the horizontal cursors are the same as on the previous screenshot (OM2 cold).   It seems that the optical gain was about 1.1% lower with OM2 hot than cold, although fitting these two thermalizations to an exponential might bring them closer by as much as 0.2%. Our current ring heater settings are 0W on ITMY, 1.5 W/segment on ETMY and 0.44W/segment on ITMX and 1W/segment on ETMX.

Since this is a different result than in the past times of OM2 changes, I've gone back to look at old times when we did this change.  One possible explanation for the difference could be ring heater settings being different. 

• 12/18/2023, cooled off while unlocked, optical gain increased 1.8% ETMX +ETMY RH 1W, ITMX 0.44W
• 9/19/2023, heated while unlocked, optical gain dropped 1.9%   (this time is confusing, it seems like the thermistors which had been disconnected were plugged in and looked to be thermalizing, but the set power was unchanged).
• 7/19/2023, heated in steps, 71484 ifo unlocked and relocked several times, perhaps calibration was reset making optical gain comparison confusing. (it did seem to drop by about 2%, but this seems more like a calibration reset) ETMX + ETMY RH 1W/segment, ITMX RH 0.44W/segment
• 7/12/2023 OM2 cooled off in lock, lockloss happened in the early part of the cooling (2% optical gain increase), ETMX + ETMY RH 1W/segment, ITMX RH 0.44W/segment
• 6/27/2023 OM2 heated while in lock, optical gain dropped by 2%, ETMX + ETMY RH 1W, ITMX RH 0.44W/segment, 0 on ITMY.

Once the OM2 heater was turned back on, the optical gain increased by nearly 1%, but the IFO lost lock before that thermalization finished.  There was a 2% decrease in POP18 during the cool off and a 3 urad shift in SRM top mass. 

While OM2 was hot, we did a few tests.

• We had a large change in the SRCL offset needed to reduce the squeezing rotation: 86739  This is interesting, in the past we have tried to change SRM alignment to see an impact on this number and it was a much smaller change.
• No squeezing time for a senstitivty comparison (not much change): 86788
• quick squeezer data set (before SRCL offset updated: 86736 with SRCL offset updated: 86739 ) , to see a comparison with OM2 cold see Camilla's plot from this morning
• Jennie Wright did DARM offset steps with OM2 hot, and cold.