J. Kissel, for J. Freed At the last minute on 2026-06-18, Josh figured out that we had errantly been sending the SPI's double mixer two copies of a COS wave of 4096 Hz rather than a SIN and COS (LHO:90680). This was because someone had errantly put a 90 [deg] rotation in the SIN analog output path. He fixed it before he left, but didn't save it in the SDF system and it got lost during Monday's bootfest of h1seih23 (LHO:90689). I'm not sure if Josh (or anyone) tuned it to any specific value, but I've changed the SIN analog rotation phase to 0.0 and accepted it in SDF so we don't lose it. Josh may add some more details in the comments below, in the comments to his LHO:90680.
J. Kissel I'm looking to get some overnight data of the SPI pathfinder so start looking at science signals and debugging. Jennie has been turning OFF the laser via the external-to-PSL Uniblitz shutter controller (see LHO:90491) over this past long weekend, and each night this week because she was worried about the stray beam from the FBR_PWRIN PD, but again -- this is 0.2 [mW] and not an issue for humans or equipment as long as the LVEA is laser hazard. She didn't know the power was so low, and followed her good instincts. But yeah, I want to get some over night data, so I've turned ON (unshuttered) the SPI laser input via the Uniblitz shutter controller box by the PSL. I'd like to leave it ON as long as the LVEA is laser hazard. If we need to go back to laser safe and I'm not around, one can easily shutter the laser by turning OFF the controller box: power it off with the rocker switch on the back, or unplugging the box from the wall, or both. With no power, the shutter defaults to CLOSED, which blocks the SPI pick-off path (only) from inside the PSL, thus making the entire SPI laser system laser safe anywhere outside the PSL.
Ibrahim, Oli, Thomas, Betsy
Before we flew the BBS in, we did a sanity-check experiment to compare slider values with a laser-pointer optical lever. This experiment follows Jeff's G1200698 math for an optical lever (picture also attached).
Setup:
A laser pointer was pointed at the BBS HR side such that the HR and AR reflections could be seen on a paper near the laser pointer. The initial position was recorded on a paper, and then slider values were driven to their maximum range in P and Y. The distance between the laser source and the HR surface was recorded. The experiment was done with BOSEMs and then with QOSEMs.
Method:
When the laser pointer is incident on the BBS, there are two reflected beams (AR and HR). The average distance of these was taken along with the average distance from the BBS. This was done by calculating the distance to the BBS and adding the half-thickness of 30mm. This gives us "one beam" and "one distance' to go off for P and Y. See the attachment below for an image of the paper used during the experiment. This was done once for BOSEMs and then again with QOSEMs.
A few notes:
Results and Analysis
Pitch is in purple and Yaw is in Orange. The equation used was obtained from "G1200698, the Oplev Infamous Factor of Two", which is essentially the same outline as our experiment, a diagram of this is attached.
This equation is: DØ= DS/2L Where,
Ø is the angle in radians (adjusted to urad below), S is the displacement in the beam spot, L is the distance from the laser source to the optic.
For these data, the total range of the Opticalign sliders was considered (from lowest negative to highest positive). Thus, a half the range would apply if the sliders were zeroed.
| BOSEM | QOSEM | |
| Distance from HR surface (in) | 130 | 118 |
| Distance from HR surface (mm) | 3302 | 2997.2 |
| Average distance from optic | 3332 | 3027.2 |
| Pitch Displacement Total - +-1500 cts | 5.5 | 5.75 |
| Yaw Displacement Total +-4000 cts | 46.75 | 40.75 |
| Pitch Angle Swept (urad) | 825.33 | 949.72 |
| Yaw Angle Swept (urad) | 7015.31 | 6730.64 |
| Total Pitch Count Sweep (+-1500) | 3000 | 3000 |
| Total Yaw Count Sweep (+-4000) | 8000 | 8000 |
| Pitch urad/Ct | 0.28 | 0.32 |
| Yaw urad/Ct | 0.88 | 0.84 |
| Pitch Ct/urad | 3.63 | 3.16 |
| Yaw Ct/urad | 1.14 | 1.19 |
Conclusion:
Next Steps:
Next, we're going to compare these results with the M3 AOSEM readouts once these are reliable. We will also compare these results with the model (which is used to corroborate slider calibration). Ultimately, this will help with the calibration of our slider values (both within the actuator slider actuation vs. sensing and from counts to real units).
Once we get a working OpLev (it's not on the BBS right now), we'll be able to get a more fine measurement of this kind.
Again, this is just a gross alignment check for information about our pointing and the capacity of our actuation.
J. Kissel, J. Wright, T. Shaffer, J. Warner, J. Freed (belated aLOG covering 2026-06-22 activity) After enjoying a lovely long, Juneteeth Holiday weekend, TJ and I wrapped up the few loose ends that were left after the 2026-06-18 super push to get everything installed (see last update; LHO:90676). - As a fall out of LHO:90667, Jim, Arnaud and I discussed the pros and cons of using the current, D1000907-v7, balance mass "Payload & Suspended Mass Assembly" arrangement in regards to the W9 corner. We concluded that leaving the D1000907-v4 configuration for this corner in place -- i.e. having 11.6 [kg] of mass in small, modular, optional components -- was better that having one "giant" 10 [kg] mass in "the same" location (on the table top, but in the same W9 corner). As such, we left the plates as re-installed on LHO:90713, with the acknowledgement that the final configuration to create a balanced ISI may be different even further than D1000907-v7. - Using a beam profiler, we measured the Beam Profile of the beam returning from M_C1 on the HAM23 ISIJ Reflector. This is to, at least roughly, confirm the radii of curvature of the M_C1 mirror. We expected a 2 [mm] diameter beam, and we got a 2 [mm] beam diameter. A more thorough aLOG to come. - We did NOT address the stray beam that Jennie mentions in her summary -- yet. I'll also write a separate aLOG on this, but in short -- it's a ~0.2 [mW] beam that's what ~18% reflection there is off of a silicon diode, and it hits the -X/-Z rim of the chamber of the +Y door, and the (splotchy) spot size is ~4-5 [mm] in diameter. The SPI team has been aware of this beam since testing in the optics lab (see mention of it, e.g. in LHO:90455), but hoped that it would land on some part of the SPI Shroud assembly, but it *just* misses it. With this last item, we consider the Installation and Integrated Test Plan COMPLETE (T2500024) ... to as good as possible with the HAM3 ISI still locked. And that ... qualifier is a "just in case" qualifier, as it's a "we'll see what happens" when the ISI gets unlocked, and we've got an excellent amount of remote adjustability to be able to recover the MEAS IFO's alignment if HAM3 moves a lot between - "locked," - "re-balanced and damped" and - "isolated with feedback and DC positioning engaged." Essentially, we've launched the SPI pathfinder into space, and now its up to out built-in remote controlled actuators and sensors to take us home to achieve our scientific goals (see T2600019). Super congrats to all, and similarly large thank you. We did a thing!
WP13303 Reimage PWRCS Beckhoff, update Corner HEPI Pump controller INI
Patrick, Erik, Jonathan, Dave:
Patrick created a new H0EPICS_PWRCS INI file. All of the EPICS channel names have changed since the first version of this system, and 40 of the new channels have old-channel equivalents. To preserve recent minute trends, the data acquired so far were transferred to the new names as part of the upgrade.
The sequence followed was:
- Remove the old names from the edc_green_ioc IOC. 43 disconnects at this point (40 from H0EPICS_PWRCS and 3 from H1EPICS_HEPIPUMPL0)
- Create the copy scripts to be ran on TW0,TW1 to copy the old files to the new, so that the new channels will "continue from where we left off"
- Create the new H1EDC.ini and verify its changes.
- Stop daqd on TW0 and TW1
- Run the copy scripts on TW0 and TW1
- Restart the 0-leg, followed quickly by restart of the EDC.
- Wait till 0-leg was fully operational, including TW0
- Restart the 1-leg
All went well except for the usual GDS1 needed a second restart, FW1 restarted itself after 5 minutes.
Continued from 90691. Betsy, Keita, Sheila, Oli, Eric, Camilla, Ryan S, Jenne
First thing, we went back to alignment we had ITMX SQZ the "flashes" and "fly-bys" yesterday, put the same size oscillation on the BS, but saw no flashes of fly bys. Betsy took a video of what the two SQZ beams looked like at PR2 at this alignment, they were crossing each other.
We then rethought the alignments from yesterday, we are leaving:
Once we did this, we had SRY fringes, Betsy and I then adjusted the BS to bring the beams back on top of each other at PR2. This was a change in the BS sliders from (P 1000, Y 1290) to (P 1350, Y 1180).
Keita then wobbled ITMX and found the SQZ beam off ITMX! Aligned ITMX to get MICH flashes at AS_AIR, AS_A/B and ISCT1 REFL. He had to move ITMX from (P -96, Y 104) to (P -280, Y 94).
He then got the PSL IX and IY reflection in the AS_AIR camera in this alignment. Sliders at this alignment attached.
However as we are not sure we trust the ITMY alignment form top mass osems (from 90551), we want this Pitch change to be in ITMY, so ITMX is at it's known DRMI pointing. We could try to walk these, maybe along with SRC which might reduce some of our Pitch differences in SR2 and SRM. This change is so small that we will go ahead with mechanically offloading BS Pitch. The BS YAW will not mechanically changed.
The OMs are also not currently in their O4 sliders/osems position, attached. We could verify the SQZ beam pointing by putting these back if we thought that was needed.
Since IMTX was moved today, I had to move PR3 to compensate in order to regain IMC flashes in the AS camera as well as ISCT1 camera.
H1:SUS-PR3_M1_OPTICALIGN_P_OFFSET is now -247.0 (used to be -140).
H1:SUS-PR3_M1_OPTICALIGN_Y_OFFSET is now -245.0 (used to be -583).
Workstations were updated and rebooted. This was an os packages update. Conda packages were not updated.
TITLE: 06/23 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: MAINTENANCE
Wind: 3mph Gusts, 1mph 3min avg
Primary useism: 0.01 μm/s
Secondary useism: 0.08 μm/s
QUICK SUMMARY:
Pictures of as-built balance mass of ITMs taken today to compare with drawings in anticipation of rebalancing both ITMs with the added baffle weight
ITMY:
table: pic1, pic2, pic3
corner 1 side wall: pic4
corner 2 side wall: pic5
corner 3 side wall: pic6 and pic7
ITMX:
table: pic8, pic9, pic10
corner 1 side wall: pic11
corner 2 side wall: pic12, pic13
corner 3 side wall: pic14, pic15
The as built configuration (redline) was uploaded to the dcc:
Shohana, Michael, Fil, Jim, Arnaud
wp 13344
Following up from 90652. The CRS chamber side testing started:
Adding numbers for the fringe contrasts for each PD:
HoQI 1 (right):
Sin: 85%
Cos: 80%
MCos: 84%
HoQI 2 (left):
Sin: 70%
Cos: 5% (electronics issue)
MCos: 71%
Ibrahim, Oli
Today, Oli and I installed and centered the M2 BOSEMs and centered and attached the cables for the M3 AOSEMs. AOSEM and BOSEM cams were also inspected and centered.
A few notes:
Next:
[Tom, Ibrahim, Oli]
Summary: The yaw / pitch coupling seen on the BBSS is not due to the the coil driver chain.
As noted in LHO alog 90665, we are seeing strong pitch yaw coupling on the BBS, when actuating via the top stage QOSEM coils. When we try and adjust the optic yaw we see a 1:5 response in pitch and vice versa. This is seen in both the QOSEM readouts, and visually using an IR beamcard on the PSL beam bouncing off the optic.
To investigate whether the cause was electronic in nature, we went into chamber to ensure that only the F2 and F3 QOSEM coils are being driven when requesting yaw drive. We used a multimeter to measure the voltage drop across the coils, to determine whether theyre being driven or not. As we expected, only the F2 and F3 coils are being driven, with equal and opposite magnitude, when trying to drive yaw. This suggests that this coupling is not coming from the coil electronics chain, or an issue in CDS.
I took an opportunity while the BSC team was in the control room and opened the light pipe and aligned the WFS on IOT1 while JAC was unlocked.
This was done at 200mW.
I used the manual adjustment knobs on the picomotor mounts as the IOT1 table is not hooked up to its pciomotor controller currently.
Got both WFS A and B as close as I could using this method. NB: pitch and yaw on QPD A are swapped as the manual pitch adjuster changes the yaw degree of freedom. I need to check this in the physical wiring for the QPDs.
Eric, Ryan S, Camilla
Went onto SQZT7 and checked on the M^2 profiler. It needed their alignment procedure ran but as we're aren't at a set alignment we did not do this yet.
In the control room we used the ASC set up in 88777 and had to adjust the H1:SQZ-ASC_TRIGGER_THRESH_ON/OFF, it worked well when we changed PSAMS but we then realized we needed a ZM4/5 ASC rather than a ZM5/6 ASC for SQZT7 profiles. Tried just changing the output matrix, did not work.
Strangely, when I used the SQZ IFO ASC screen's "!graceful clear history", we now have outputs in the LOCK OUTPUTs but the beam looks a lot clearer on AS_AIR camera. We are now in a different alignment than we have been, but it's better on AS_AIR so we'll reassess tomorrow...
Jennie W, Jeff K, Josh F, TJ S,
Summary: SPI interferometers aligned, shroud installed successfully. One stray beam and possible clipping on shroud to investigate/deal with but otherwise all problems were solved. Obligatory success photo taken by Josh.
Today we:
More details regarding the baffle installation:
When placing the below table baffle brackets, there was a ballast mass baffle (D1700262) that was blocking the angle bracket for the furthest -Y bracket. The bracket could not slide under the ballast mass baffle (bmb), so we decided to move the bmb in the +Y direction a few inches and I had to loosen the baffle panel within the feet to slide it up a few mm and then reclamp. This allowed the bracket to slide under the baffle just to the side of the feet, but the move partially exposed a corner of the shiny ballast mass stack.
The lower baffle shroud that covers the breadboard needed the fiber spools to be moved. We moved them over one set of bolt holes, but they are quite close to chamber edge, I'd guess around 1/2". Jeff then centered the two aperatures to the SPI beam, and we called it good. We still need to B&K the whole area.
Just did an 8 hour trend of the fiber power monitor channels for REF and MEAS channels (left two plots) and the optical lever QPDs (right two plots) to check whether we expect variations on the order of ~2V on the QPDslike we saw on Thursday before and after baffle installation.
From this trend the power appears to drift more than this for two hours after unshuttering the laser (around 15:56 UTC), but once it reaches a steady state both QPDs were only drifting by 1V and the fiber power input monitor PDs by 1V or less.
Conclusion: I think we would have seen a dramatic power drop on Thursday when we installed the shroud, that I would expeact to have been much larger than the trends I saw today.
Note mentioned in the summary of activities in the main entry -- per LHO:90667, we re-installed all the ballast or balance mass discussed during this 2026-06-18 day's session. See attached "after" picture.
Here's another picture of the SPI breadboard on HAM3 prior to the baffle installation. Photo credit is ?? maybe Jeff?
J. Kissel, J. Warner During SPI install we removed the following side-wall balance mass from the W9 side wall (see first bullet of LHO:90558): Plate Mass [lbs.] Mass [kg] QTY Total Mass [kg] D071200 Type 04 7.9 3.583 3 10.750 D071200 Type 01 1.1 0.499 1 0.499 D071200 Type 00 0.6 0.272 1 0.272 D071201 0.1 0.045 3 0.136 Total Mass 11.657 First attachment is a diagram to convey which side wall I'm talking about. This is inaccurate with the latest version of the ballast / balance mass inventory, D1000907-v7, which states that this side wall has only 1x Type 04 (3.583 [kg]) and a 1x Type 03 (2.041 [kg]), for a total of 5.625 [kg]; much less. Remember, from LHO:90504 that the total SPI mass is 12.599 [kg]. This *excludes* the mass of the lower ISI Shroud baffle (D2400106-v4) and the three upper HAM Table Baffles (D2600007) with all their bracketry and bolts, currently only represented only in e-drawings posted to D2400103-v6. After talking with Jim, he wants more mass in this -X / +Y corner of the table, because that's where all the new stuff is. So he wants this corner "over" or "heavy" (because the new stuff must be in a fixed position) so that he can adjust the *opposite* corner of ballast mass (which has more open table and side wall access and thus is adjustable). As such, he says "put all the at 11.657 [kg] back on the corner. So we will! Second attachment is a picture of the wall mass arrangement prior to us removing it taken on 2026-06-09.
Masses were re-installed as of 2026-06-18! See LHO:90713.
The ETMY BRS seems to be continuously ringing up. I've tried to make the changes to the thresholds which was the previous fix outlined in 87634 for the same BRS, and will check back in on it later to see if just increasing the thresholds helped at all.
Changed thresholds:
H1:ISI-GND_BRS_ETMY_LOWTHRESHOLD 800-->2000
H1:ISI-GND_BRS_ETMY_HIGHTHRESHOLD 2000-->4000 Changed
Additonally I changed the ETMX BRS drift control to 6.00V and the ETMY BRS to 2.00V to try and better center them
[Shoshana, Jim]
Shut off the damping for ~2 hours hoping it would damp down somewhat but the ringing just got worse
Jim recaptured the ETMY BRS frame to see if that would solve the problem, but it did not.
We went down to the BRS to test if the dampers were wired correctly/making contact. We checked the voltage going through and applied a voltage directly to the dampers to make sure the wires in vacuum were connected to the plates. We found that the 2 pin (+ direction) and 5 pin (- direction) (diagram below) were the pins which applied voltage to the dampers, were applying voltage as expected (maxing out at around 2.9V). It looks like applying a voltage directly made the BRS move as expected (we applied 3V to each pin one at a time in order to ring it up or damp it down), so we don't think there is an issue with the connection, and voltage was making it through the cable.
After watching the signal and the voltage going through the cable for a while, my best guess is that the + damping doesn't turn off fast enough when the BRS switches directions which causes it to continuously oscillate, but switches off eventually so it doesn't continue ringing up?
Michael Ross (who wrote the Beckhoff code) will be here next week, so we will ask him to take a look at it.
Michael is in this week and fixed the EMTY BRS by raising the upper threshold (H1:ISI-GND_BRS_ETMY_HIGHTHRESHOLD) from 4000-->8000 for 20 minutes, see 90693
Current Thresholds:
H1:ISI-GND_BRS_ETMY_HIGHTHRESHOLD: 4000
H1:ISI-GND_BRS_ETMY_LOWTHRESHOLD: 2000
Looking through ndscope it the same changes were made to the ETMX BRS, raising the thresholds
Looks like this issue has popped back up. When Michael Ross was here he increased the damping thresholds (see 90693) which seemed to fix it temporarily but starting last night ETMY got stuck again in a damping loop. I'm going to shut off the damping for maybe 20 minutes to see if that fixes things and if not I'll mess with the damping thresholds again.
Turning off the damping for 20 minutes seemed to reduce the velocity slightly, but it still seems stuck in a loop with the velocity under 2000 counts, which happens to be the lower damping threshold. I then turned back on the damping and have let it run for another ~30 minutes and it looks like the BRS has damped back down. If this continues to be a recurring issue it might be good to look into a more permanent fix, but just switching the damping off and on again seems to work for now.
During investigation I found that that SUS-R2 rack was energiezed by about 1mV. This was found to be caused by SPI RF Splitter being attached to the rack directly. I ran out of time to correct this before my visitation ended