S. Muusse, C. Compton, G. Valente

Alignment of 4.65um beam on the ITMY was completed, excluding the QPD optics which require reflection off the ITM. I've attached a picture of the almost complete table with the notable optics modified today indicated. I'll get someone taller to add a better picture in the comments of the whole table.

• All the PD optics were placed and aligned (another picture).
• The PD electronics (x-arm Chassis & PD power supply) were temporarily installed and slow and monitor channels were shown to be operational.
• Thermal pickoff aligned.
• The beam dump flipper orientation has been problematic but has been solved by dumping when the flipper is vertical and placing the beam dump at a ≈ 30deg angle (picture attached).

Next steps:

• Installing the visible laser and associated optics
• Testing the rotation mount and translation mount
• Testing y-arm chassis

The Medm screen is now in a workable form if not particularly finessed.The screen is called TCS_CHETA.adl and a shortcut was added for the X and Y arms by camilla to the TSC screen.
There is still work to be done here calibrating the powerdetectors and power meters.
note: currently power in for the rotation mount .adl is the laser diode current and should be changed to laser power when calibrated

TITLE: 02/26 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: More HAM1 work done today, we're very close to closing
LOG:
Sophie will post log as comment

J. Freed, J. Warner

We set up a small rack to be put into the optics lab for the SPI build housing (most) SPI electronics and hooked up all the power cables for these electronics (For the build we are using a dual source RF generator to instead of the 80MHz OCXO and Single Sideband Mixer like in the final set up). Before this set up can be used, a RF power meter should to be used to check to make sure the correct RF power is going to the AOMs in the SPI laser prep chassis. 

After applying power to the TIA chassis I also checked that the DB25 on the front panel of varient 2 of the TIAs was correctly outputing -15V on pins 1-10. 

Results:

Pins 1-4,7-10 were outputing -14.8V

Pins 5-6 were outputing -15.1V

This discrepancy in pins power is expected and is caused by the fact that the Variant 3 TIA is the one that is actually powering pins 5-6 through the front panel DB9 cable from varient 3 to varient 2. 

J. Kissel, R. Short, J. Oberling

This is the first installment of aLOGs documenting the setup of a new stand-alone 1064 nm NPRO laser system whose current "end game" intent is to provide ~100 [mW] of fiber-coupled p-pol light to the SPI laser prep chassis.

Step 1: Gathering materials, find what optics / mounts we had vs. what would be need, and physically layout the plan.

Jason lets Ryan and I know that there are three NPROs in the optics lab, two of which are PSL spares that cannot be used. 
The remaining laser is S/N 1661, the laser used in the PSL during O3 which is *functional* but was briefly installed during O4 circa Fall/Winter 2024 then removed from use in the PSL because of reported glitching / incompatibility with the frequency stabilization servo (FSS) issues -- see the bottom of LHO:81391 for a nice summary, and LHO:81409 for record of its removal.

Inspired by the setup at Stanford Sina shared with us, we're looking to build up the following system to accomplish the goal:
    - NPRO (presumed to be elliptically polarized with Is / Ip = 5:1)
    - QWP (to linearize the polarization)
    - HWP1 (to rotate the polarization into horizontal)
    - FI (accepts horizontal linear polarization, to ensure back-reflections from down-stream components don't seed the NPRO causing glitches/mode hopes/frequency noise)
    - HWP2 (to rotate the FI output polarization into the desired amount of vertical polarization -- aka the desired amount p-polarization)
    - PBS (to filter out and dump the unneeded horizontal / s-pol light, and transmit the desired power of p-pol)
    - SM1 (one of two steering mirrors to align the beam into the fiber collimator)
    - L1 (the single-lens mode-matching solution to convert the NPRO beam into what the fiber collimator needs)
    - SM2 (two of two steering mirrors for alignment into the fiber collimator)
    - 50:50 PWR BS (45 [deg] AOI, optimized for p-pol; to provide a pick-off port for live power measurement)
    - Fiber Collimator

Ryan started with a 24" by 12" breadboard that was lying around in the optics lab. He build up a makeshift stand from three posts and dogs in the lower left corner such that the S/N 1661 NPRO projects the beam at 4" height. The 0.5" thick breadboard has a 1 inch hole pattern offset by 0.5" from the edges. I'll refer to this grid as having axes "m" and "n" where the m-axis are the "row" holes running from 0 to 23, and the "column" n-axis holes run from 0 to 11. I chose (m,n) breadboard coordinates so as to not confuse them with traditional beam profile coordinates of (z [propagation distance], x (transverse horizontal), y (transverse vertical)). 

Thus, the NPRO being in the "lower left" means it projects the beam along the m = 3 row, and the front face of the NPRO is sitting at n = 8. We'll call this beam position z = 0.

We then proceeded to gather as much as we could of optical components from the optics lab drawers, and ended up with this pictured preliminary version of the setup.

Step 2. Power up the NPRO.
Here's were we ran into our first snag. Normally, NPROs are paired/tuned with specific controller boxes. However, when Ryan turned on the S/N 1661 laser with the S/N 1661 control box, the crystal temperature readback reported the temperature was quickly, linearly rising well beyond the desired temperature of 24.7 [deg C]. At ~42 [deg C], (but still below the internal automatic watchdog threshold of 50 [deg C]), Ryan knew something was wrong and turned it all off. He repeated the turn on just in case, and it did the same.

After conversing with Jason, we figure it's good enough to run with one of the other controllers for now, and in the mean time figure out how what's wrong and repair the S/N 1661 controller.

So, we're running with the S/N 7974, and things seem fine. 
    Laser Diode Temp Setup:
        Diode 1 33.7 [deg C]
        Diode 2: 33.1 [deg C]
        Laser diode injection current readback 2.08 [A] (for both diodes)
    Crystal Temp setting is 24.7 [deg C]

We measured the output power*** with no optical elements at all as 1.820 +/- 0.005 W (not noisey, but a slow drift around).
Good enough! Onward and upward!

*** Power measured by ThorLabs power meter
	Model S302C
	SN 111149
	Sensing factor of 316.25 [mV/W]
	(last calibrated Feb 3 2012).

The PM1 suspension started swinging longer than usual and exceeded its RMS trip levels for 20 minutes continuous at 11:44 PDT this morning. This caused an IOP DACKILL on all three LIGO-DACs.

I was able to reset and bypass PM1 and restore the SUS DAC drives at 11:57.

Currently HAM1 SWWD has PM1 permanently bypassed so this cannot happen again.

F. Clara, K. Kawabe, M. Pirello

We checked the following for ground loops:

CER:
Beam Diverter Cables - Both tested good.

From SUS R1:
JM1 is good
JM2 is good
JM3 is good
PM1 - Pin 2 is grounded, Shield is not connected to pin 13 (cable HAM1_311)
RM1 - Shield is not connected to pin 13 (cable HAM1_228)
RM2 is good

From ISC Racks:
ISC_222 (db9) pin 5 not tied to shield, signals good
ISC_221 (db9) pin 5 not tied to shield, signals good
ISC_226 (db9) pin 5 not tied to shield, signals good
ISC_356 (db25) pin 13 IS tied to shield, signals good
ISC_223 (db25) pin 13 not tied to shield, signals good (older cable)
ISC_224 (db25) pin 13 not tied to shield, signals good (older cable)
ISC_225 (db25) pin 13 tied to shield, signals good (new cable)
ISC_227 (db25) pin 13 tied to shield, signals good (new cable)

EOM RF Signals:
At Rack, all RF signals shields are tied to rack ground.
Cable runs are isolated from rack and chamber ground
At Chamber, all RF signal shields are tied together in chamber possibly at EOM.

IOT2 Table Enclosure:
Picomotor Cable - pin 13 tied to shield, signals good.

J. Freed, J. Kissel

We worried for the production, already class-A clean, SPI's single-element PD (SPD) assembly (D2600001) that the unused GAP5000 pins of the dual-purpose D1700116 ceramic circuit board may have shorts from FFD-200 SPD case to its anode and cathode if the case of the PD was not insulated from those GAP5000 pins -- as was found possible in the dirty test setup (see list item 2. in LHO:89247).

This morning, we opened up the cleaned assemblies (still serialized under the drawing for the cable, D2400341),
    - S2500514 :: HAM3 ISIK MEAS A and MEAS B
         --Pins 5-9 -> PD Box S2400197 -> DCPD 001
         --Pins 4-8 -> PD Box S2400198 -> DCPD 002
    - S2500515 :: HAM3 ISIK FBR PWR REF and FBR PWR MEAS
         --Pins 5-9 -> PD Box S2401094 -> DCPD 004
         --Pins 4-8 -> PD Box S2401093 -> DCPD 003
    - S2500516 :: HAM3 ISIK REF A and REF B
         --Pins 5-9 -> PD Box S2401096 -> DCPD 005
         --Pins 4-8 -> PD Box S2401095 -> DCPD 006

And found that for every assembly,
    - Per D2400341, only pins 1,4,5,8, and 9 exist. See example picture of S2500514
    - All the anode (5 or 4) or cathode (9 or 8) pins are isolated from the case pin (Pin 1)
    - The anode pins for the two diodes (5 and 4) are isolated from each other
    - The cathode pins for the two diodes (9 and 8) are isolated from each other
    - Each diode's cathode to anode resistance (5 to 9 and 4 to 8) is in the ~2e6+/-1 [Ohm] = ~few [MOhm] as expected for the reverse bias operation we'll use the system.

The production PD assembly will function as designed without any shorts :: the negative reverse bias topology of the transimpedance amplifier and cable readout system will work!

I also attach pictures of the bags that aide assignment of serial numbers to assemblies.

Wed Feb 25 10:02:04 2026 INFO: Fill completed in 2min 3secs

A messy fill, CP1 has been dribbling since the dewer fill yesterday so it was close to full, resulting in a quick fill or sorts.

The JAC steps finally completed to a point where we are ready to hand over to Jim to finish the cabling pinning and ISI balancing.  This morning the LVEA has been transitioned to full laser safe and the IOT1 JAC table has been moved out of the way of the chamber.  The viewport fixture still needs to be removed, will get a crew on that soon.

Adding CHETA slow controls channels to DAQ EDC

Jonathan, Erik, Dave:

Following the installation of the CHETA Beckhoff chassis in the Vacuum Prep Lab we added the 724 AWC channels for itm[x,y] to H1EPICS_ECATTCSCS.ini for inclusion into the EDC.

at 12:22 I did a DAQ 1-leg and EDC restart. The EDC would not run, its systemd service was in a continual respawn state.

The number of EDC channels had increased from 59894 to 60618, and I remembered that there is a channel limit in the EDC code, which Erik verified was 60k.

Erik quickly built a new EDC with a 70k limit and installed this on h1susauxh56.

In the mean time I had put the H1EDC.ini file back and restarted 1-leg and EDC to get everything stable again.

At 13:22 we did a second round of DAQ+EDC restarts with the expanded channel list which was successful.

Installing h1sush6 IO Chassis

Fil, Dave, Erik:

I relocated the old h1sush2b IO Chassis from the CER to the MER. It is in the bottom of the SUS-HAM6 rack, at the same height as the neigboring h1sush7 and h1seih7.

I pulled a new MTP fiber from the IO Chassis to the MER patch panel, using the third port.

This IO Chassis currently has the cards left over after the h1sush2[a,b] consolidation in Dec 2025, we will populate it with the correct cards later.

Current layout:

No work was done on the front end computer in the MSR.

Later this week when the IO Chassis is powered up we will make the following changes in the MSR to the old h1susb2b computer:

1. disconnect the Dolphin cable from its IX card and verify the Dolphin switch port is fenced

2. move the MTP from the CER patch over to the 3rd port on the MER patch

3. run puppet to reconfigure the boot server to boot this computer as h1sush6 sans-Dolphin and only running h1iopsush5 model

4. boot the computer and verify the IO Chassis can be seen, the IOP runs and that the timing is good.

h1susb123 accumulated 4 DAQ CRC errors on the 1-leg overnight as reported by DC1, but none on the 0-leg.

All 4 models on h1susb13 increment their CRC counters at the same time. Normally we have zero CRC errors for weeks/months across the board.

I have cleared the CRCs and we will see if this trend continues.

TITLE: 02/25 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: 9mph Gusts, 6mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.19 μm/s 
QUICK SUMMARY:

More JAC work today

The annulus ion pump body for the BSC1 annulus system was replaced.  We then hooked up and started the turbo/aux. cart.  Pressure at the cart was dropping nicely as pumping commenced.  

There will be a pump cart running on the south side of the Y-arm beamtube, near the TCSY table, until the ion pump transition pressure.

J. Freed (with help from Marc and Fil)

I tested the real wiring chain described in D2400111 from PD through the 3 variants of the TIA and it does follow exactly what is described in the link. There were 4 things of note that were found during this test. 

1. All the whitening filters were switched "on" inside the TIA, however our final design document states that only the QPDs need whitening. As such the SPD boards S2500647 and S2500645 whitening switches were set to bypass. I logged this change in the E-Traveler.

2. The D1700116 silicone circuit board for the FFD-200 causes shorts. The main issue is the GAP 5000 pinholes on the PD side of the board. If the PD is flush with the board those pins touch the case of the FFD. Since the GAP pins are also connected to the cathode and anode, this causes the circuit to short. This is simple enough to test without taking out any PDs from the case. If there is "no" resistance between the case (ground) pin and the anode/cathode pins on the DB9 connector coming from the PD, then it is shorting and the system should not be turned on. There are 2 options suggested to fix this, either put insolation between the GAP pins and the FFD case or cut the GAP pins connection to the FFD anode/cathode. For this specific test, the issue was bypassed by putting in a tissue between the FFD and the silicone board.

3. I tried to take transfer functions from all the PDs through the TIA, however the laser I used (the MIT ISC AM Laser) AM modulation was designed for 5 - 200 MHz, not the 4096Hz we are trying to use. As such, I suspect the harsh attenuation (~70dB at 4096Hz AOM_Attinuation.png) I measured was caused by the laser. So I decided it would be better to put off the transfer functions through the TIA until after SPI is built, then use our own laser AOM system to run the test. The laser was just left at DC and was used as the light source to see if signals on the PDs follow the correct wiring chain.

4. I used the laser to check that the signals on the PDs follow the expected wiring chain through the output of the TIA. Ex. Laser on Quadrent 1 of the QPD outputs a voltage on the expected pin on the output of the TIA. All pins were found to be correct.

Ansel, Sheila, Camilla

Last week, Ansel noticed that there is a 2Hz comb in DARM since the break, similar to that that we've seen from the HWS camera sync frequency and power supplies and fixed in 75876.  The cabling has not been changed since, the camera sync frequency has been changed.

Our current camera sync frequencies are: ITMX = 2Hz, ITMY = 10Hz. We have typically seen these combs in H1:PEM-CS_MAG_LVEA_OUTPUTOPTICS_Y_DQ. With a 0.0005Hz BW on DTT I can't easily see these combs, see attached.