This morning we have pushed the JAC EOM by about 0.6mm (using ~25 thou thick washers) in -Y direction, following the finding of last Friday (alog 89158).
After that the beam was good on the input side plate (the beam is offset in +Y direction by 0.1mm) and was OK on the output side plate (0.5mm offset in -Y direction).
The beam position on the crystal itself should be ~0.13mm in +Y direction on the input face and ~0.36mm in +Y direction on the output face. The angle between the nominal path and the actual path outside of the crystal is about 0.6 degrees. See pictures and cartoon.
Calculation depends on the refractive index, I assumed n~1+deflection/wedge=1+2.35/2.85~1.85, but using 1.85+-0.5 instead won't change anything in a meaningful manner.
This is acceptable, the beam is more than 1.5mm away from the side face of the crystal, cannot remember the beam radius but it should be smaller than 600um if FDR is still valid, so it might be 2.5 beam radius or maybe more.
IFO REFL beam check was done.
After Jennie restored the IMC alignment to post-IMC axes check state, IMC was locked, PRM was alignmed and the IFO refl beam in HAM1 was quickly checked to see if the REFL air path somehow interferes with the new POP periscope stiffener. It didn't.
JM3 swap is ongoing.
Partly in the interest of time, I asked others to go ahead. Rahul and the team are working on it right now.
Yet to be done items:
I calculated the mode-matching before we replaced JM3 and got a limit of 0.26 % for the mode-mismatch as the TM20 mode was hidden in the noise at 100mW input power. We turned up the whitening gain to 42 dB from 30dB to have a better chance and still couldn't see it.
This plot shows the zoomed out ndscope of the TM00 modes and this one shows the max value for TM20.
After JM3 was installed and its position, pitch and yaw had been tuned by Rahul and Betsy to optimise the pointing through our HAM1 irises, Keita, Jenne and I tried to tweak up the alignment with JM3 sliders.
I have left the sliders near here and could not get them much better.
I measure the mode-matching to be 0.43 % with this alignment which is worse by at least a factor of two.
See photo of TM20 mode here.
The 10 and 01 modes are much higher than they were previously, so we will need to do some alignment of the fixed JM2 or JAC_M3 mirrors.
Note for the MM measurement we were accidentally scanning with the MC2 length and the PSL laser frequency so this might make the measurement confusing.
I closed the light pipe and turned up the purge air before going home.
Let me point out that the term “mode matching” used in Jennie’s post is not exactly accurate in this case; it would be more precise to refer to it as the TEM20/02 mode peak fraction. Since there is a large misalignment, the second-order modes are also enhanced. Therefore, that contribution should be subtracted before attributing the remaining fraction to mode mismatch.
FAMIS 39953
Starting about two weeks ago, the pressure at the EX station started getting more "noisy" for some reason. Not sure why this would happen or how significant it is, but noting it here just in case.
Jennie W, Ryan S, Keita K
Summary: MC suspensions back to good time from 10th of Feb, we should only lock the IMC length loop manually during this installation period to avoid the WFS engaging.
Today Ryan and I had the task of figuring out why the IMC suspensions seemed to be badly aligned on Friday.
We found a good reference time 16:48:29 UTC on Tuesday 10th Feb at the end of the period where Olli, Jenne and I set the IMC axis back to its nominal state before the vent using ASC loops for DOF 1 and 2 of the IMC plus manual moves of the JM3 mirror in chamber as this cannot be moved by an ASC loop as it is not a tip-tilt currently. See photo of the WFS and MC mirror top mass OSEMS here. Note it is important to choose a time when IMC is in the locked state as the MC2 mirror gets mis-aligned when the IMC guardian is offline.
We figured out that the alignment was changed about 19:33:17 UTC on 13th Feb probably by the IMC guardian as Elenna used it to lock the IMC for phase check measurements. See photo, where the vertical cursors are set at the good reference time and today.
After some investigation of the guardian we reminded ourselves that DOFs 3-5 are turned off in the IMC WFS MASTER filter banks. DOF4 and 5 are normally off and DOF3 is intentionally left off because of the replacement of PSL PZT actuator by JM3.
When the IMC guardian is used to lock it automatically triggers the WFS through some logic from the simulink model, and so when Elenna used the guardian to lock it turned on the feedback to DOFs 1 and 2.
Until we install the JM3 tip-tilt and are finsihed most commissioning of the HAM1 hardware we should only lock the IMC manually by engaging the MC-L servo using the common mode servo board controls.
Keita and I zeroed the M1 LOCK fiters for all 3 MC mirrors and I changed the alignment sliders so the M1 osems were back to their values from the reference time on the 10th. See photo of ndscope.
To ensure the IMC WFS loops don't cause the MC mirrors or the PZT upstream of JAC to move on us like they did last week, we've turned the outputs of the IMC-DOF_{1,2,3}_{P,Y} filters OFF. Since these outputs are not touched by the IMC_LOCK Guardian, we can now safely use the Guardian to lock the IMC without the concern of WFS turning on and changing alignments.
At some point, the h1ascimc model will need to be updated to send the output of the DOF_3 loop to JM3 instead of the PZT (and medm screens updated too), as that's what's immediately upstream of the IMC now.
Closes FAMIS#28228, last checked 88988
TCSX: 30.5 - Did not add water
TCSY: 10.4 - Did not add water
Flow and filters looked good, but had to remove a notification about preventative maintenance for the filter for both chillers (TCSX, TCSY) in order to see the flow rates.
No leak in water cup
Workstations were updated and rebooted. This was an OS packages update. Conda packages were not updated.
Tue Feb 17 10:13:47 2026 INFO: Fill completed in 13min 43secs
FAMIS 31125
Since the FSS and ISS were re-enabled last week, things have generally been stable in the PSL. The RefCav could probably use some alignment touchup, but it's not too bad for now.
FAMIS 39751
Laser Status:
NPRO output power is 1.834W
AMP1 output power is 70.51W
AMP2 output power is 138.8W
NPRO watchdog is GREEN
AMP1 watchdog is GREEN
AMP2 watchdog is GREEN
PDWD watchdog is GREEN
PMC:
It has been locked 3 days, 19 hr 53 minutes
Reflected power = 26.72W
Transmitted power = 103.9W
PowerSum = 130.6W
FSS:
It has been locked for 3 days 15 hr and 53 min
TPD[V] = 0.4774V
ISS:
The diffracted power is around 4.0%
Last saturation event was 3 days 19 hours and 53 minutes ago
Possible Issues:
PMC reflected power is high
TITLE: 02/17 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: 8mph Gusts, 5mph 3min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.39 μm/s
QUICK SUMMARY: The HAM1 JAC EOM will have some slight alignment adjustments made today before placing the JM1/3 suspensions in their proper positions. HAM7 continues to pump down.
Mon Feb 16 10:13:39 2026 INFO: Fill completed in 13min 36secs
Sun Feb 15 10:13:40 2026 INFO: Fill completed in 13min 36secs
Sat Feb 14 10:14:53 2026 INFO: Fill completed in 14min 49secs
FW0 spontaneously restarted itself at 17:49 Friday 13th February 2026.
The DAQ was last restarted 16:05 Thursday 12th February, and FW0 had been running 1day 1hour 44minutes at the time it restarted. There have been no further restarts.
TITLE: 02/14 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Productive day with the HAM1 EOM being adjusted to recover IMC alignment, which locked easily and has a good REFL demod phase. Sounds like the EOM needs to be moved again slightly next week, but that's been prepped for this afternoon. A few AUX carts were disconnected in the LVEA as well today.
LOG:
| Start Time | System | Name | Location | Lazer_Haz | Task | Time End |
|---|---|---|---|---|---|---|
| 22:49 | SAF | LVEA is Laser SAFE | LVEA | NO* | LVEA is Laser SAFE *BIFURCATED HAM1/2 | Ongoing |
| 16:31 | FAC | Kim | LVEA | N | Technical cleaning | 17:46 |
| 17:27 | CDS | Fil, Marc | LVEA | - | Cable pulling (HAMs 3/5 HEPI offline) | 20:16 |
| 17:55 | JAC | Keita, Jason | LVEA | Y | JAC EOM alignment | 20:25 |
| 18:21 | FAC | Randy | LVEA | N | Working on test stand (W-bay craning possible) | 20:40 |
| 18:51 | VAC | Gerardo | LVEA | N | Checking on pumps | 19:16 |
| 20:11 | SEI | Jeff | Opt Lab | Local | SPI work | 23:59 |
| 21:20 | CDS | Fil, Marc | LVEA | - | Cable pulling (HAMs 3/5 HEPI offline) | 22:46 |
| 22:43 | JAC | Jason, Tony | LVEA | Y | JAC REFL alignment | 00:25 |
| 22:49 | VAC | Gerardo | LVEA | N | Disconnecting AUX carts | 00:05 |
| 23:21 | PEM | Robert | EX | N | Grounding work | 00:45 |
| 23:57 | JAC | Keita | Opt Lab, LVEA | Y | JAC EOM alignment prep | Ongoing |
Keita has come back from the LVEA, Light Pipe is closed for the weekend.
JAC Guardian has been taken to down.
(Travis S., Jordan V., Gerardo M.)
Late entry-
Late Wednesday we vented the annulus system for HAM4 using nitrogen. On Thursday, we removed and replaced the ion pump, a very uncomfortable location for this pump, it is surrounded by cable trays, see photos.
We have not been able to fasten the mounting bolts that hold the ion pump body in place, we have noticed that the pipes for the annulus system leading up to the mounting flange are not parallel to the ion pump flange they are |/ and they should be ||. So, we have to twist the pipe to be able get it parallel to the pump. We have a mechanical block supporting the pump as a temporary support, we'll replace it as soon as possible.
Today, I visited HAM4 ion pump and turned the controller on, it railed at first, and a few minutes later it was at nominal value, and after it reaching a bit below 2 milliamps I closed the isolation valve for the annulus system, an hour or so later the aux-cart, can turbo and hoses were removed. Ion pump pressure signal has turned around and getting lower, nice! Good job, Jordan and Travis.
Morning report.
Pictured the beam position on the input and the output side plate of the EOM.
We'll see if it's off or not, doesn't look bad but we'll see once I have time to look at the pictures.
We realigned the beam into IMC, mode mismatch < 0.4%.
I just assumed that the MC alignment itself was good. I found MC2 in misaligned state and changed it to aligned.
We had to work both on PIT and YAW, but mostly in PIT (i.e. the difference in horizontal beam deflection between the old batch crystal that we're using and the new batch crystal is smaller than the difference in vertical deflection).
Good news is that the mode matching is still pretty good. Attached is the MC2 trans VS time while the PSL frequency was ramped. Assuming that the tiny thing pointed by the green arrow is actually 2nd order HOM peak, the mismatch is 0.036/9.4~0.4%. Consider this as an upper limit, because it's hard to tell if the "peak" is actually a peak, could be noise fluctuation.
Afternoon:
Tony and Jason worked on REFL path: alog 89154.
Elenna confirmed that the demod phase for IMC didn't change: alog 89149.
We'll have to move the EOM again.
Looking at the pictures shot this morning, the beam seemed to be a bit too much in -Y direction relative to the EOM aperture especially on the output plate.
Assuming that the wedge angle is the same (2.85 degrees per surface) and the deflection angle is the same (2.35 degrees per surface) as the new batch, the EOM should move at the input by about 0.7mm and at the output by about 1mm, both in -Y direction.
We'll move the entire structure by marking the +Y edge of the EOM pivot base plate using two dog clamps and then inserting washers between the dog clamps and the base.
I measured the edge thickness of four big slotted washers, they're not uniform in thickness (they're not machined after all) but they're all between 24 and 29 thou (between 0.61 and 0.74mm). Inserting one big slotted washer per dog clamp might be good enough.
(Jordan V., Travis S., Gerardo M.)
Pumpdown was restarted this morning around 9:11 am local time. After pressure inside HAM7 reached 0.5 Torr we switched over to the turbo, we had a very smooth transition. After the internal pressure of HAM7 reached 5.0x10-05 Torr all O-ring isolation valves were closed (we have one at the turbo pump, another at the chamber and one more at the relay tube).
HAM7 internal pressure after 12+ hours of pumping is 5.2x10-06 Torr. The attached plot has a small glitch at the 10 hour mark, likely due to the DAQ restart.
Annulus ion pump update. The ion pump controller was turned on this morning, the ion pump controller struggled for some time as it was railed, but we did noticed that the pressure reading reported by the aux-cart (aux-cart remains connected and pumping on this system) dropped very slow, but after a some minutes the ion pump controller was not railed no more.
(Jordan V., Gerardo M., Travis S.)
Update for HAM7 pump down and other accessories.
- Pressure internal to the chamber continues to drop, slow but it is making progress. Plot attached. Pressure as of this entry is at 1.27x10-06 Torr.
- HAM7 Annulus system update, the ion pump made some good progress. The ion pump has settled down to 3 milliamps, good pressure reading, this allowed us to remove the aux-cart, can turbo and hoses from this ion pump.
- HAM7 RGA system, yesterday we connected an aux-cart+can turbo combo to this system, we are pumping it down to get it ready for use, but first we need to leak test the conflats that removed from the +Y door.
(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.
EPO taggin'.
(Jordan V., Gerardo M.)
After a couple of days of "assisted" pumping, the annulus system isolation valve was closed. After a day of solo pumping the ion pump was able to maintain the annulus pressure at nominal. Now the aux-cart, can turbo and hoses were removed, pressure looks good.