Sheila, Tony
On Friday we continued trying to get flashes in the filter cavity for 1064nm, 532nm, and IR light onto the SQZT7 diode which we are using to establish that we are going through the VIP without clipping.
At the start of the day we saw IR flashes of at max 0.04 counts on SQZ-FC_TRANS_D_LF with the OPO locked with CLF (with 21mW on CLF trig PD) 1.7 counts on FC_TRANS_C_LF with 5mW into the green fiber, and 36e-6 counts on OPO IR PD. We saw that the green was clearly misaligned in yaw in the filter cavity, and we were able to improve the IR flashes and IR on SQZT7 with some yaw moves, but that made the green flashes nearly disappear. We pio'd MOTOR 3 (H:M2) -710 counts, which improved the green flashes to 6 counts.
Then we could see that the IR flashes and on SQZT7 were easiesr to improve with pitch moves, and that we no longer loose the green by improving them, so we spent some time trying to walk ZM1/2/3 for slow improvements, to get IR flashes of 0.1 counts, 83e-6 on SQZT7, and green flashes of 5. (22:30 UTC March 20th)
This was slow going, so we decided to go back to FCES with cameras to see if we could get some photos or see flashes. We will continue from the FCES this afternoon.
Betsy wanted a look at the last few months of dust trends for BSC2.
(This is Dust Monitor LVEA10 which was moved to BSC2 in Feb [alog89137].)
One of the flashlight arrays we used during the vent had a bunch of battery corrosion in each battery compartment.
I used isoprop and water on long q tips to clean these out in the optics lab. It is now drying on the bench next to the fume hood. See first pic.
Unfortunately I didn't realise the sink hadn't been used in while and turning this on splashed water on some nearvby electtronics, second pic.
The pipes attached to the taps also leak.
I dried off the silver box and the extension block after powering off the extrension block, it was just some water spraying on it so should be fine.
Erik, Marc, Dave:
I've updated the CDS Overview to show the timing card firmware as a color block in the RGC version section of the IOP model.
For each IOP model, the top part of this block shows the RCG version, GREEN=5.5, BLUE=5.5.2. The lower part shows the Timing Card version, GREY=old, DARK-BLUE=new.
For user models this block just shows the RCG version as before.
FAMIS 31130
Not much to report this week. Noisy FSS TPD times line up with the IMC naturally flashing through resonance, and looks like there were some temperature spikes for a few days last week, but these appear to have stopped.
Hepi Pump Trends (Monthly) Famis 39954:
On Jan 26th the HPI-PUMP_EX_PRESS1_PSI started rising in maximum pressure. and on maybe feb 2nd it started getting worse. Seems like it has plateau-ed on Feb 16th, but the Pressure still remains elevated.
That channel back in Oct was between 92.4-92.6 PSI.
And now it's between 91.9 - 93.5 PSI. I'm not sure if this is out of bounds for HEPI.
X-Arm electronics:
All chassis have been tested mounted in the rack. All that is left is to replace the variable power supplies currently being used for the visible laser, fan and flipper with 5V, 12V and 15V DIN mounted power supplies respectively.
X-Arm beam profiling:
X-arm is not behaving as predicted by the model especially in the horizontal axis.
The beam was profiled using the nano scan along a 55cm length after the second lens and a q-parameter was fit using this data.
This is compared to the model and a Jammt model using the measured QCL q and assuming a linear optical system with the lens at the same distances as in the physical set up.
For the fit q-parameter the w at the ITM was found by propagating the q at L2 to the ITM.
Additionally, during the trouble shooting process a wedge was found on the first telescope lens (L1) which isnt in the optical system and was compensating for some of the astigmatism of the QCL. The effect of this is that in the data below the beam size at the ITM is too large and astigmatic.
Discussion and solutions of this effect will be the subject of its own log.
Vertical
| Measurement/model | w0 [ µm] | z [mm] | w at ITM [mm] |
| Fit from data |
978.9±22.7 |
-1063.1±33.8 |
50.09 |
| Fintrace |
857.11 |
-500.64 | 61.38 |
| Jammt | 874.53 | -572 | 62.1 |
Horizontal
| Measurement/model | w0 [ µm] | z [mm] | w at ITM [mm] |
| Fit from data | 1280.3+/-54.9 |
-1813.3±83.5 |
38.01 |
| Fintrace |
979.42 |
-653.71 | 54.38 |
| Jammt | 1013 | -256 | 53.1 |
None of the values agree within the measurement uncertainty bounds, especially in the horizontal direction. We are also observing non-gaussian beam profiles on the nano-scan, plots attached, but this is predominately in the vertical direction. This structure isnt new and appeared when matt and I were initially profiling the lens and were able to see good agreement.
The fintrace and Jammt are close but not identical which would be expected as the Jammt does not include any additional optics outside the QCL and L1 and L2. We are currently working on determining the source of this discrepancy.
Mon Mar 23 10:06:23 2026 INFO: Fill completed in 6min 19secs
Only CPS channels which look higher by eye at high frequencies (see attached) would be the following:
TITLE: 03/23 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: CALM
Wind: 4mph Gusts, 2mph 3min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.22 μm/s
QUICK SUMMARY:
Arm (GV5/7), FC gate valves closed (GV7 is soft-closed, waiting to cam over). Cleanroom move this morning. Lots of activity around the Y-Beam Manifold begins!
As part of our investigation into h1ioplsc0 timing glitches since last week's h1lsc model change, I restarted all the models on h1lsc0 at 08:07 PDT this morning.
I've extended the alarm bypass on GV7 for another 24 hours.
Bypass will expire:
Tue Mar 24 09:17:05 AM PDT 2026
For channel(s):
H0:VAC-LX_GV7_ZSM179A_VALVE_ANIM
Sun Mar 22 10:03:10 2026 INFO: Fill completed in 3min 7secs
CP1 PT114 cold cathode gauge has come back to life, I've taken it out of the alarm bypass and enabled it in VACSTAT.
Sat Mar 21 10:09:41 2026 INFO: Fill completed in 9min 38secs
(Jordan V., Gerardo M.)
Yesterday we tried to hand over the pumping of HAM1 to the ion pump only, it did not go good, the ion pump started having issues maintaining pressure for HAM1 volume, this ion pump showed a very unusual behavior, the pressure was going up and the output of the controller kept going down. We tried a second controller with similar results. The controllers just quit and turned the high voltage off themselves, self protection/preservation. Today, we went up to the ion pump and ohmed out its feedthrough fischer connector, and to our surprised no short was found, we were convinced that the pump had shorted. So, we took a controller chamber side and connected it with a "short" cable to the ion pump, and the pump turned on without issues. These findings lead us to believe that the cable may be faulty/shorted/broken/no good.
The temporary setup will be used to maintain the ion pump under vacuum, and the setup will remain until another suitable cable (working one) can be acquired and installed.
Attached are a couple of photos of the temporary setup and trend of the controller/pressure at HAM1 behavior during the last couple of days.
(Jordan V., Gerardo M.)
We hard closed GV5 with no issues, the gate valve hard closed at 30 psi. Something to note is the loud clank the gate valve made, and when the valve hard closed it shook the cameras housing, probably the alignment is not what it used to be.
We tried to hard close GV7 but no luck, it soft closed only. We slowly increased the pressure up to 35 psi, and the gate valve remained unchanged. For the activities planed for Monday soft close is good, we will visit the GV7 on Monday.
Then, we moved to close the filter cavity tube isolation valves, we closed FCV-1, FCV-2, FCV-3, FCV-4 and FCV-5. We also isolated the relay tube by closing RV-1 and RV-2, the filter cavity volume will likely go up in pressure.
This is a belated report of work done by me, Oli and Keita on the OMC builds for the BHSS, done yesterday March 19.
Exciting summary: build for OMCA is complete, including DCPDs and butter dish. OMCA is installed onto the BHSS platform and ready for beam alignment!
Less exciting summary: build for OMCB is halted as tombstone for DPCD A (transmission) is missing a required PCB hole for the electronic connection.
OMCA build notes:
OMCB build notes:
[Elenna, Camille, Arnaud]
We had a quick zoom meeting to discuss this issue. Relevant drawing is https://dcc.ligo.org/D1201273
It is likely that the backshell+PCB assembly was assembled flipped 180 degrees (items 4,5,6 on the drawing). To fix, remove the two 2-56 screws (item 14), flip the assembly and reattach it to the housing. Camille suggest slightly pressing down on the housing while removing those screws to avoid torquing the base with the bond.
Tagging for EPO.
After consultation with Arnaud and Camille, Oli and I were able to correct the problem with the PCB assembly.
On the call with Camille and Arnaud, we referred to the diagram in D1201273 and determined that part #4 is rotated 180. I could also see from this diagram that part #5 is rotated, since there was no notch visible at the top. So, for future installation, make sure the notch in part #5 is oriented upwards! This indicated to us that all that needed to happen was to unscrew the #14 screws, flip the assembly, and screw it back in (we had some concern that we might have to take apart the "sandwich" of parts between #5 and #4).
Indeed, that's all that needed to happen. I carefully unscrewed the screws on the back, flipped the assembly, and screwed it back in. I was then able to install the DCPD. We can now see the notch along the top!
I went back into the lab today to try to get a better photo of the problem. I wasn't able to, but I did get an ok photo of the other tombstone (on reflection of the BS) which has the correct three holes. It's hard to see, but you can use it as a reference to compare with the photo I have attached to the original post which is missing a hole. I tried looking from many angles, and I don't see even a hint of the third hole, which is evidence in support of Keita's theory that the electronics assembly is flipped 180 degrees.