TITLE: 01/14 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:
Today's big activities: JAC alignment continues at HAM1. SUS model/daq work continues from Control Room and CER. HAM7 squeezer alignment continues.
LOG:
Marc, Jeff, Fil, Oli
Yesterday we pulled most of the AI chassis (D1000305 or D1600077) from SUS-C1 and SUS-C6, modified them for ECR E2400409 and E2500296 (IIET 35739 and 35706, respectively), and reinstalled them as part of our work converting SUSB123 and SUSH34 into SUSB13 and SUSB2H34 (88765).
Every AI chassis in SUS-C1 and SUS-C6 was meant to be pulled, upgraded, and reinstalled EXCEPT SUS-C1 U24. Additionally, we needed to also modify a spare D1000305 AI chassis for installation into SUS-C2. We did all this, but along the way we accidentally also pulled and upgraded the AI chassis in SUS-C1 U24 (previously S1104380). Luckily, we hadn't modded the spare (S2100712) yet so we installed it into SUS-C1 U24 and installed that modified chassis in the SUS-C2 U14 spot.
Here are the steps for how we modified the AI chassis:
- Disconnected all affected AI output cables in SUS-C1 and SUS-C6
- Removed the existing 6x 2x 8CH DAC AI chassis (D1000305 or D1600077),
- Modified them to become D2500353 1x 32CH AI chassis
. Replaced the 2x 8CH AI rear panel with WD relays (D1000551) with 1x 32CH AI rear panel without WD relays (D2500097)
. Replaced the 2x 8CH back panel (D1000552 with 1x 32CH back panel (D2400308)
- Relabeled AI chassis from D1000305 to D2500353, or from D1600077 to D2500397, and reinstalled
- Cabled everything up according to the corresponding version of the wiring diagram (SUSB13, SUSB2H34)
Pulled, upgraded, and reinstalled:
D1000305 > D2500353 D2500097
SUS Chain Rack / Position Chassis S/N Rear Board S/N 32CH DAC Card / IO Slot Channels
ITMY M0/R0/L1 SUS-C6 / U38 S1108073 S2501317 DAC0 / Slot#2 0-15
ITMX M0/R0/L1 SUS-C6 / U37 S1108072 S2501319 DAC0 / Slot#2 16-31
ITMY L2, ITMX L2 SUS-C6 / U35 S1108074 S2501316 DAC1 / Slot#4 0-15
MC2 M1,PR2 M1,SR2 M1 SUS-C1 / U31 S1104379 S2501321 DAC2 / Slot#5 0-15
SR2 M1, MC2 M2/M3 SUS-C1 / U30 S1104368 S2501320 DAC2 / Slot#5 16-31
D1600077 > D2500397
Chassis S/N
ITMX ESD, ITMY ESD SUS-C6 / U21 S1600245 S2501318 DAC1 / Slot#4 16-27
Upgraded and newly installed (technically was pulled from SUS-C1 U24 by accident):
BS M1/M2 SUS-C2 / U14 S1104380 S2501322 DAC3 / Slot#6 0-11
NOT upgraded but chassis swapped:
D1000305 D1000305
SUS Chain Rack / Position Chassis S/N Before Chassis S/N Now
PR2 M2, PR2 M3, SR2 M2, SR2 M3 SUS-C1 / U24 S1104380 S2100712
J. Kissel, F. Clara, O. Patane, M. Pirello, D. Barker ECR E2500296, E2400409 WP 12962 D2300401 (for susb13) and D2300383 (for susb2h34) G2301306 -- PARTII 2023 plan, PARTII Update We've completed all electronics hardware moves, cabling/recabling and new installations that we plan to do on SUS MC2, PR2, SR2, BS, and the future LO1 and LO2 for now. Given that this change to the electronics is somewhere in between versions of the D2300401 h1susb13 and D2300383 h1susb2h34 wiring diagrams -- the interim configuration we're in now that Does have - susb2h34 and susb13, as well as susauxb13 and susauxb2h34 with all their ADC and DAC cards, as they will be in O5. - All of the BS electronics have been moved from SUS-C5/SUS-C6 to SUS-C1/SUS-C2, and their CER cabling dragged along with it - all AI chassis driven by 28-bit 32CH DACs (7 in total) have been converted from a pair of D1000305 2x8CH DAC AIs to a pair of D2500353 1/2x32CH DAC AIs. - ITM AA chassis inputs (both OSEM sensors, optical levers, and CD monitors) and AI chassis outputs have been re-arranged such that the grouping is far more sensibly arranged and modular per QUAD. Doesn't have - BBSS-like BS TOP mass converted to QOSEMs - BBSS-like BS M3 OSEM sensing and actuation electronics - Any LO1 or LO2 electronics - The BS optical lever in its final AA chassis position (because the BS TOP mass OSEMs still need that spot) - Any changes to the field cabling - the BS M1 satamps, M2 satamps, and M3 optical lever whitening chassis are all still in SUS-R6) -- we planned /documented all of this work on google slides -- see PARTII Update -- which is linked in the abstract of G2301306. We'll add more details, gotchas, and pictures below in the comments.
Wed Jan 14 10:10:16 2026 INFO: Fill completed in 10min 12secs
Fil, Marc, Richard, Jeff, Oli, Erik, EJ, Jonathan, Dave:
WP12962 Move BS for upgrade to BBSS. WP12901 Upgrade ITM to LIGO-DAC
On Tuesday 13Jan2026 we reconfigured the BSC1,2,3 and HAM3,4 suspensions to move the BS control from h1susb123 to h1sush34 and upgrade the ITM test mass suspensions to use the new LIGO-DACs. Associated changes were also made to these systems' SUS-AUX frontends.
Frontend Computer Renaming:
| old name | new name |
| h1susb123 | h1susb13 |
| h1sush34 | h1susb2h34 |
| h1susauxb123 | h1susauxb13 |
| h1susauxh34 | h1susauxb2h34 |
Prep Work:
The 4 LIGO-DACs used for this upgrade were calibrated in the EE shop and FE tested on the DTS.
The EDC was moved from h1susauxb123 to h1susauxh56
Upgrade:
The h1susb123 and h1sush34 suspensions were SDF reconcilled and put into their safe state.
The SWWD seismic systems were put into an infinite bypass.
All 4 front end were powered down and work on their IO Chassis, AAs and AIs started.
h1susb13 IO Chassis
8 20bit-DACs removed, 2 LIGO-DACs added.
Removed 20bit-DACs
| 20bit-DAC | 18/20bit-DAC Interface Card |
| 200217-17 | S1200228 |
| 220218-29 | S1200227 |
| 210303-49 | S1200224 |
| 210303-35 | S1200219 |
| 210303-22 | S1200220 |
| 200217-19 | S1200221 |
| 210303-57 | S1200226 |
| 220218-08* | S1200229 |
* 20bit-DAC 220218-08 installed in new h1susb2h34 chassis.
New Adnaco Layout
| Adnaco slot | Card [interface] | Adnaco slot | Card [Interface] | |
| A1-1 | LIGO Timing Card | A3-1 | empty | |
| A1-2 | empty | A3-2 | empty | |
| A1-3 | ADC0 (orig) | A3-3 | empty | |
| A1-4 | LIGO-DAC0 S2500457 [010] | A3-4 | empty | |
| A2-1 | ADC1 (origin) | A4-1 | BIO0 (orig) | |
| A2-2 | LIGO-DAC1 S2500448 [011] | A4-2 | BIO1 (orig) | |
| A2-3 | empty | A4-3 | BIO2 (orig) | |
| A2-4 | empty | A4-4 | empty |
h1susauxb13 IO Chassis
Removed last 2 ADCs, installed them in h1susauxb2h34 IO Chassis. ADC count went from 8 to 6.
h1susauxb2h34 IO Chassis
Added the 2 ADCs from h1susauxb13 in next available slots. ADC count went from 6 to 8.
| ADC | ADC Card | Interface Card |
| ADC6 | 110128-11 | S1102417 |
| ADC7 | 110128-03 | S1301433 |
h1susb2h34 IO Chassis
Original layout skipped Adnaco slot A2-4. Reviewed as-built drawings and alog but could not find why this slot was not being used. Assuming that there was something wrong with this slot I replaced the second Adnaco backplane
| Suspect Backplane (removed) | C8610415 |
| New Backplane (installed) | C8610796 |
Original layout was:
2 ADC, 5 18bit-DAC, 1 20bit-DAC, 2 BIO.
Update: keep the 2 ADCs, remove all 5 18bit-DACs, keep the 1 20bit-DAC and add a second 20bit-DAC, add 2 LIGO-DACs and add a third BIO.
Table of removed 18bit-DACs + IF
| 18bit-DAC | Interface Card |
| 110425-10 | S1104013 |
| 101208-71 | S1104017 |
| 110425-04 | S1104014 |
| 110425-09 | S1104023 |
| 110425-46 | * |
* Because the 18bit and 20bit DACs use the same Interface card, this IF card was left in the chassis for the second 20bit-DAC
New Adnaco layout
| Adnaco slot | Card [Interface] | Adnaco slot | Card [Interface] | |
| A1-1 | LIGO Timing Card | A3-1 | empty | |
| A1-2 | empty | A3-2 | empty | |
| A1-3 | ADC0 (orig) | A3-3 | empty | |
| A1-4 | 20bit-DAC0 (orig) | A3-4 | empty | |
| A2-1 | ADC1 (orig) | A4-1 | BIO0 (orig) | |
| A2-2 | 20bit-DAC1 * | A4-2 | BIO1 (orig) | |
| A2-3 | LIGO-DAC0 S2500454 [012] | A4-3 | BIO2 ADRBS96001188 | |
| A2-4 | LIGO-DAC1 S2500442 [013] | A4-4 | empty |
* 20bit-DAC1 ss0218-08 repurposed from h1susb123 surplus.
Timing Card Firmware Upgrade (Marc)
All 4 IO Chassis Timing Cards had a firmware upgrade. This was essential for the control frontends, which would not be able to drive the LIGO-DACs without the new firmware. The SUS-AUX TCs were upgraded as part of the general upgrade of all frontends.
| Tming Card Firmware Version | |
| old | 1 - 0x1f0 |
| new | 2 - 0x635 |
Model Changes and Current Status
| h1iopsusb13 | New model name, installed but needs SWWD review |
| h1susitmx | Not running, being reworked |
| h1susitmy | Not running, being reworked |
| h1susitmpi | Not running, being reworked |
| h1iopsusb2h34 | New model name, installed but needs SWWD review |
| h1susbs | New location, not running, being reworked |
| h1susmc2 | Not running, being reworked |
| h1suspr2 | Not running, being reworked |
| h1sussr2 | Not running, being reworked |
| h1iopsusauxb13 | New model name, running and complete |
| h1susauxb13 | Temporary model running, being reworked |
| h1iopsusauxb2h34 | New model name, running and complete |
| h1susauxb2h34 | Temporary model running, being reworked |
All models are being built with RCG5.5.2, which is needed to drive more than 1 LIGO-DAC.
TITLE: 01/14 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: 6mph Gusts, 4mph 3min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.45 μm/s
QUICK SUMMARY:
Foggy morning on site where the LVEA continues to be in Laser HAZARD for in-chamber work at HAM1 & HAM2.
MuseumEXP continues with new-exhibit work at LExC this week.
My last shift was in 2025. Some notes:
Jennie W, Masayuki N
Daniel set up some model changes last week in h1lsc to allow us to use the JAC-TRANS_A DCPD to lock the cavity. This is a workaround of what is intended to be the normal operation where the locking is done with the JAC-REFL_A PD on IOT1. Rolling this table up to the chamber would make it hard to install the optics on that side of the table so we need this workaround to see the beam transmitted through the cavity that we can use to align the beam from JAC into the IMC.
This PD is just a DC PD so we cannot use PDH to lock as we would for the REFL PD. Yesterday and today Masayuki and I worked on an offset lock, where we use the transmitted power offset to the side of the fringe after normalising the error signal by the maximum transmitted power on resonance.
Use JAC Overview->DITHER. The demodulation is set up so the SIN gain is one and connects to I filter bank which also has a gain of 1. Q filter bank is terminated at the output.
First step is to use the ramp on JAC Overview -> JAC-PZT_Driver by pressing "ENABLE" in right-hand corner, the slider on the left side needs to be near -10V for this to work. Measure the max peak height of the TM00 mode - transmitted power off resonance.
The normalisation is done using the high pass filter bank block at the left of the screen, this opens up H1JAC-DITHER_PD_IN. The gain should be set to the normalisation constant, 1/(transmitted power on resonance - transmitted power off resonance).
The actual servo shaping is done using H1JAC-DITHER_SERVO, which is linked on the right of the 'DITHER' screen. Set the offset to -0.6 to shift the normalised error signal so the zero crossing is just below halfway up the fringe. Check the input and output of the filter bank after the servo are turned on, this is linked on the right of the 'DITHER' screen and is called 'PZT'.
Make sure the PZT ramping is turned off by pressin 'DISABLE on the JAC-PZT_Driver screen.
Turn on the UGF100 and LP10 filters in the 'H1JAC-DITHER_SERVO' filter bank. These have a gain of 3000 and a low pass filter which rolls off at 10Hz respectively. This latter one is to invert the PZT response.
The gain in this filter bank should be on, use the slider on the 'DITHER' screen to tune to a TM00 peak and then turn on the servo output. Once locked you can turn on the Int1Hz filter to add an integrator below 1Hz and the boost to give an extra 5x gain.
For a better lock we also implemented a proper DITHER SERVO.
The dither frequency is set to 2.5KHz and the demod phase is set at 0 degrees. The input signal no longer had normalisation in H1JAC-DITHER_PD_IN as the error signal will now be the beat between the PZT dither and the cavity transmitted power and so has a zero crossing at the centre of resonance.
There is a high pass filter in H1JAC-DITHER_PD_IN to avoid up-conversion of noise below 1 kHz. After the demodulation both 'I' and "Q' filter banks have a low pass filter at 1kHz to prevent 2.5kHz and harmonics from getting magnified by the loop.
Both I and Q phase now have a low pass filter at 1KHz to prevent harmonics of the dither frequency appearing in the error signal. The locking technique is the same after this point as the filters needed in the 'SERVO' block do not change as the actuator response has not changed.
Masayuki has set up both these locking processes in the JAC guardian but this is still WIP.
Here is the measurements we took so far.
Offset Locking erro point ASD when locked.
RyanS told me yesterday that he could re-isolate the ETMX ISI. I finally got to looking at it today and something was off with the CPS. Using the weekly CPS spectra script I got ASDs for the CPS from last night and a bunch of the the CPS spectra were way off, first image.
I went to EX and looked at racks, SEI chassis all looked fine. I unplugged a couple of CPS probes at the chamber and did not get the expected behavior. One CPS went to the near limit rail (-32k) the others hardly changed at all. This made me suspect timing, so I traced out the timing sync wires, found the 71Mhz CPS timing fanout and the lights were all off. Looked at the power strip and only the -18v led was on. Turned off the fanout chassis, took some pics and found Marc and Fil.
Marc came to the end and we looked at power supplies in the front of the building and the +18 for the rack was dead. We swapped both power supplies for spares, and CPS timing seems to have come back, I was able to isolate the ISI. Marc said the fans seemed a bit stiff and smelled weird, so maybe another fan failure.
Per WP12970
ISC-R1 +18V supply failed this afternoon. This set was slated for replacement, so we replaced both legs.
+18V S1300287 was replaced with S1202002 with new ball bearing fan installed.
-18V S1300275 was replaced with S1201995 with new ball bearing fan installed.
M. Pirello, J. Warner
Tue Jan 13 10:09:38 2026 INFO: Fill completed in 9min 34secs
TITLE: 01/14 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Another busy day of upgrades; JAC installation and HAM7 beam alignment continued while the move/upgrade of BS DACs began today and should wrap up tomorrow morning. Jim also discovered a failed power supply at EX which looks to be the reason the chamber can't be recovered, so he and Marc are starting to take action there.
LOG:
| Start Time | System | Name | Location | Lazer_Haz | Task | Time End |
|---|---|---|---|---|---|---|
| ---- | SAF | HAZARD | LVEA | YES | LVEA is Laser HAZARD | Ongoing |
| 16:27 | FAC | Kim, Nellie | LVEA | - | Technical cleaning | 17:18 |
| 16:41 | CDS | Marc, Fil, Oli | CER | - | SUS computer upgrades | 20:22 |
| 16:49 | CDS | Jeff | CER | - | SUS computer upgrades | 21:04 |
| 16:49 | CAL | Tony | PCal Lab | Local | Check measurement | 20:17 |
| 17:01 | JAC | Rahul | LVEA | Y | JAC installation | 19:42 |
| 17:24 | SQZ | Sheila, Elenna, Kar Meng | LVEA | Y | HAM7 SQZ beam alignment | 18:25 |
| 17:27 | JAC | Jennie | LVEA | Y | Opening light pipe | 17:33 |
| 18:30 | CDS | Dave | CER | - | susb123 DAC upgrades | 22:33 |
| 18:32 | JAC | Masayuki | LVEA | Y | JAC installation | 19:42 |
| 18:55 | SQZ | Elenna | LVEA | - | Replacing viewport cover | 19:07 |
| 18:56 | VAC | Gerardo | EX | N | Troubleshoot AIP | 19:36 |
| 18:57 | FAC | Kim | EX | N | Technical cleaning | 19:36 |
| 19:24 | FAC | Tyler, MacMiller | FCES | N | Air handler work | 22:33 |
| 20:01 | CDS | Richard | CER | - | Checking progress | 20:30 |
| 20:22 | CDS | Fil | MY | N | Picking up cables | 23:09 |
| 20:22 | CDS | Oli | CER | - | SUS computer upgrades | 21:05 |
| 21:11 | VAC | Gerardo | EX | N | Troubleshoot AIP | 21:30 |
| 21:13 | CAL | Tony | PCal Lab | Local | Getting serial numbers | 00:08 |
| 21:17 | VAC | Travis | LVEA | - | Looking for parts | 21:24 |
| 21:45 | CDS | Jeff | CER | - | SUS computer upgrades | 00:18 |
| 21:51 | JAC | Jennie, Rahul | LVEA | Y | JAC installation, Rahul out @ 22:47 | 01:25 |
| 22:10 | JAC | Masayuki | LVEA | Y | JAC installation | 01:25 |
| 22:24 | CDS | Oli | CER | - | SUS computer upgrades | 01:11 |
| 22:35 | JAC | Betsy | LVEA | - | Check on JAC progress | 22:47 |
| 22:35 | JAC | Keita | LVEA | - | JAC installation | 01:25 |
| 22:35 | PEM | RyanC | CER | - | Grabbing DM stand | 22:38 |
| 22:54 | CDS | Marc | MY | N | Getting parts | 23:11 |
| 23:10 | CDS | Fil | CER | - | SUS computer upgrades | 01:10 |
| 23:23 | SQZ | Sheila | LVEA | Y | Opening HAM7 viewport cover | 23:29 |
| 23:52 | SEI | Jim | EX | N | Checking electronics | 00:25 |
| 00:02 | VAC | Travis | Mids | N | Looking for parts | 00:31 |
Sheila, Kar Meng, Elenna, Jim
Yesterday Jim and I went to the chamber in the morning to work on cables. We got a solution for the cables after some work, but one peek zip tie luanched itself across the chamber. We spent a few hours searching for this; I climbed into the chamber on the -X side and could them see it on the bottom of the +Y door where Jim was able to reach through the port and retreive it.
In the afternoon Kar Meng and I went back to the chamber and found that the beam was blocked on the cable clamp that Jim and I had added earlier. The previous cable routing is shown here, the peek cable clamp is on the bottom of the pillar so that it doesn't block the beam. We removed the new alumium clamp and I tried to move it lower, the second from the top bolt hole is not the right size so we need to place this in the 3rd from the top hole. I found that difficult to reach and eventually decided to leave it for another day or ask for help from someone with longer reach.
After this we saw that our beam did arrive on AS_C in HAM6 but wasn't aligned onto AS_A or AS_B.
This morning Elenna, Kar Meng and I went to the chamber to see if we could improve the alignment. We walked B:M3 to align onto the second iris on SQZT7, and B:M4 to align onto the iris in front of ZM4, which seems degenerate with the iris at the bottom of the SQZT7 periscope. This worked well and we could see light on AS_B and AS_C although nothing on AS_A. We then went to the control room and moved ZM6 to center on AS_C better, then we could engage the AS centering loops.
This afternoon Kar Meng and I had another look at alignment from the control room. We have set the OMs back to their alignments during the run, and we still have the beams on AS_C, AS_A and AS_B although we are using a lot of the range on ZM6.
Still to do before finishing in HAM7:
Masayuki, Jennie, Rahul
Given below are the list of lenses and mirrors I have placed on the ISI table and roughly positioned (without the beam for now) them as per following drawings - D2500344 and D0901821.
Lenses - L1, L2 and L3: Masayuki confirmed from the vendor that the arrow mark on the lens point towards the convex side. For lens L1, arrow is pointing against the PEEK ring (in the lens holder). For Lens L2 and L3 the arrow is pointing towards the PEEK ring. The PEEK ring for all three lens are facing towards the HAM2 chamber. In other words, curved surface of L1 is facing towards the PSL and for L2-3 towards HAM2.
I re-cleaned L1 lens after finding some dust particles on the curved surface, post cleaning the lens looked better.
Reflecting mirrors - JAC-RM1, JAC-RM2, JM2 and M3.
Masayuki and I also added a temporary Siskyou mount acting as JM3 (for Tip Tilt, just like JM1). We will replace both of them with the Tip Tilt next week.
Next, we proceed with aligning/pointing the above optics with the beam. L1 and JM2 are already decently pointing (although without a locked JAC) towards JM3.
J. Kissel ECR E2500296, E2400409 WP 12962 D2300401 (for susb13) and D2300383 (for susb2h34) We begin the major upgrade of the H1SUSB123 and H1SUSH34 SUS and SEI Systems converting them to SUSB13 and SUSH34 a la G2301306 today. We're focusing on upgrading the DACs in the IO chassis () and all the downstream surrounding impact of that analog electronics This will take down the following computers, and they will be resurrected with new names as follows: FORMER NAME FORMER SUS NEW NAME NEW SUS h1susb123 ITMX, ITMY, BS h1susb13 ITMX, ITMY h1sush34 MC2, PR2, SR2 h1susb2h34 BS, MC2, PR2, SR2, LO1, LO2 h1susauxb123 ITMX, ITMY, BS h1susauxb13 ITMX, ITMY h1susauxh34 MC2, PR2, SR2 h1susauxb2h34 BS, MC2, PR2, SR2, LO1, LO2 As such, I've - brought the ITMX, ITMY, BS, HAM3, and HAM4 SEI systems to ISI_DAMPED_HEPI_OFFLINE (so we don't risk any "hard" trips of HEPI during all this). - brought all impacted SUS gaurdians to AUTO mode, then to the SAFE state - Increased the bypass time on all impacted software watchdogs to bypass time to a large number (90000000 secs), and hit BYPASS
Updated timing cards on newly named SUSB13, SUSB13 AUX, SUSB2H34, SUSB2H34 AUX, formerly known as SUSB123, SUSB123 AUX, SUSH34 and SUSH34 AUX.
Timing FPGA Version 1589
(Travis, Dave, Gerardo)
Dave noted and reported a rise on vacuum pressure at X-End. Since, Travis and I were in the control room, we quickly determined that the controller for X2-8 ion pump was not working. I drove down and found the high voltage disabled/off at the controller, and on on the screen the following note:"An excessive arcing condition has been detected (Error10)". No guidance found on manual, snapped a photo to submit later to vendor. I restarted the system and the HV started, controller hummed and crackled and was only able to get up to 600 Volts, all while making noise, and one point some funny smell came out of the inside of the controller, HV was disabled, time to replace the unit.
(Travis, Gerardo, Richard)
Controller remains off, and high voltage cable is disconnected at both ends, ion pump and controller.
We found a controller for this particular application, and replaced the "old" controller but with similar results, minus the noise. The controller was only able able to get up to 500 volts and no more. We turned it off and disconnected the high voltage cable.
I later visited the cable and ion pump to measured them for shorts. I disconnected the cable from the ion pump, then probed the connector at the controller side, center pin to the shell read 0.808 kOhm, I also probed the center connector to other parts of the cable, but no continuity was read for all cases, including to the conduit. The ion pump itself was probed for shorts and none was found, at the ion pump connector the center pin was probed to the ion pump body and no continuity was measured. To compare cables, I measured a "new" cable that we have that is probably half the length of the one in use, no continuity was measured.
I'll wait for the EE guys to have a free moment for them to test the cable.
[Jason, Jennie, Betsy, Keita, Sophie, Masayuki]
For the initial JAC alignment, we need to scan with laser frequency since we didn't have JAC PZT actuation. The laser frequency was swept by changing the laser crystal temperature from −0.13 K to −0.05 K with a period of 30 seconds.
The alignment was adjusted to suppress higher-order modes resonance. The actuators used were the PSL PZT and the fixed Siskiyou-mounted mirror that replaced the JM1 tip-tilt suspension. I worked inside the chamber while Jason controlled the PSL PZT via MEDM. Beam walking was performed by moving the PSL PZT first and optimizing alignment with the other mirror in the chamber. Note that due to the HAM1 periscope rotating the beam axis by 90 degrees, the pitch and yaw of the PSL PZT are effectively swapped in the JAC coordinate basis.
As a result, moving the PSL PZT by approximately 1000 counts in pitch (corresponding to yaw in the JAC basis) achieved an alignment good enough to observe the TEM_{00} mode. Further alignment will be performed using the transmission PD signal.
After discussion, we decided to delay installation of the reflection path. Since PDH locking using the reflection RF PD was therefore unavailable, we proceeded to align the TRANS DC PD and aim for shoulder locking using this signal.
In the nominal design, the TRANS PD receives light from the JAC leak port (~0.3% of the input power), picked off by a laser window with 0.7% reflectivity. However, with the current PSL power of ~100 mW, the available light was insufficient. Therefore, the TRANS PD was configured to directly receive light from the leak port without a laser window.
Due to a mistake, a post that was 0.5″ too short was prepared for the DC PD mount, and no suitable replacement was readily available. As a temporary configuration, the PD was mounted in a base–dog clamp–post–dog clamp–PD stack, using a 0.25″-thick dog clamp as a spacer.
In-vacuum cables were also wired. From the feedthrough (D4F10), a DB25 cable (D2500336) splits into three branches: TRANS PD, PZT & thermistor, and heater & thermistor. Since the ALS beam runs adjacent to the JAC, cable routing clamps were used to avoid interference with the ALS beam (see attached photos).
To enable locking using the TRANS PD, we confirmed that the corresponding signal path exists in the CDS infrastructure added by Daniel. In the H1LSC model, ADC2 channel 10 is assigned to the DC PD and routed through the dither locking module to the JAC PZT output.
In the analog path, the DCPD output from the JAC interface chassis is connected to the auxiliary PD concentrator, and its monitor port is routed to the DAC via the D-sub patch panel. Both the fast and slow channels were confirmed to be correctly connected using the actual PD signal.
The polarity of the PZT wiring was verified. For this test, the DB9 connector of the PZT & thermistor cable (D2500336) on the JAC side was disconnected, and gold pins were inserted into pins 5 and 9 of the feedthrough-side female connector (the PZT inputs). A 100-count offset was applied to the JAC_SERVO filter bank output driving the PZT, and the voltage between pins 5 and 9 was measured with a multimeter. To avoid high voltage during this test, the HV amplifier was powered by an 18 V supply instead of the nominal HV source.
Toggling the 100-count offset resulted in −10 V (off) and +9 V (on). The same behavior was observed when measuring the PZT driver output directly, confirming correct cable connections and no risk of reverse loading the PZT.
These voltage levels were not considered reasonable for normal operation, so Daniel was consulted. The likely explanation was operation with the 18 V supply instead of the HV source. After reconnecting the HV supply, injecting the laser into the JAC, and applying a ramp signal to the PZT, motion of the PZT was clearly observed in the transmission signal.
The TRANS PD was re-aligned, and the signal observed on MEDM was maximized.
The thermistor connection was also verified, yielding a reasonable reading of approximately 22 °C. Heater testing has not yet been performed, but functionality of the PZT, thermistor, and PD has now been confirmed.
In parallel with wiring checks, preparation of the optics on the JAC output side was carried out.
An issue was found with a newly fabricated ISC post (8-32 variant) intended for the lens mounts; it was confirmed that the standard D1000968 post works without issue. Keita and Sheila located suitable posts in the staging building, and three lens mounts were assembled using these posts.
Attempts to peel the First Contact from the lenses were unsuccessful, as the FC layer was extremely difficult to remove, and we gave up. Applying FC to spare optics is considered the fastest path forward, and for the stuck FC, reapplying FC to soften it may be necessary.
HR mirror preparation was also performed.
Further details of the optics preparation will be posted shortly by Keita.
Mirrors inspected:
| Mirror | status | was found | what was done |
| M2 | Not ready | in a lens container with foam sponge after the first cotnact was removed, which is a bad idea. Many dust particles after taking it out of the box. | Painted first contact. |
| M3 | Ready | Was in the chamber, first contact still on. | Removed FC while using top gun. A big dust particle in the back surface, couldn't remove with further top gun, but that's OK. |
| RM3 | Not ready | Was in the chamber, first contact still on. | Removed FC while using top gun. One dust particle close to the center, couldn't remove. Painted FC. |
M3 assy is in the chamber (but is still at the edge of the ISI).
M2 and RM3 optics are stored outside of the chamber.
Lens First Contact problem:
All of the lenses had at least one surface where the first contact was incredibly strongly attached. Simple pulling of the mesh won't do anything even with serious force. We wiggled the mesh in multiple directions with enormous force and the mesh started separating from the FC. Will discuss with Betsy on Monday. All of these are stored outside of the chamber.
| L1 | FC remains on one surface. Painted FC on top of the existing layer over the mesh. Will see if it makes the FC loose. |
| L2 | FC remains on both surfaces. |
| L3 | FC remains on one surface. |
2" Lens Post issue:
All pieces of 8-32 variant of D1000968-v3 were manufactured incorrectly, they have 8-32 bottom screw holes so cannot be mounted on the standard ISC baseplate.
To make them usable, the bottom hole should be widened and re-tapped for 1/4-20 though there's no urgency because we were able to use the original 1/4-20 version. (It seems that this variant was requested on a wrong assumption that Siskiyou lens mount only accepts 8-32. In reality the lens mount has two screw holes, one for 8-32 and the other for 1/4-20, so this variant isn't really needed.)
Tagging for EPO photos
Attached is the mode-matching layout for the VOPO. The target primary waist of the VOPO (from TT1700104) is 221.2um(s), 206um(t) for 1064nm and 159.2um(s), 148.8um(t) for 532nm.
The mode matched minor and major beam waist is 198.6um, 204.2um for 1064nm and 152.6um, 185um for 532nm. For the fundamental injection via the rear mirror, the measured waist is 197.25um, 231.85um. These waist is measured at the position marked with a "star". The mode-matching calculation has been reviewed by a fur-low scientist.
I have included a diagram showing the components remaining on the optical table, which can be used for testing the homodyne detector.
The attached file also includes the corresponding mode-matching calculation, indicating the resulting beam waist location along the remaining optical path, for future reference.