(Jordan, Travis, Richard, Filiberto, Randy, Gerardo)

Corner pumpdown started Thursday afternoon, around 4:40 pm local time.
We setup the twin mobile ISP-1000 scroll pump stations at the YBM turbo station, we chose this area due to the real estate available, the other 2 stations are a bit crowded.  After setting up all of the required equipment the pumpdown was started with procedure E2300169, to setup the turbo pump unit for the pumpdown, then Jordan and Filiberto covered procedure M1300464 to make sure all high voltage DC power supplies were off, then continued following E2300443 to start the pumpdown with the ISP-1000 scroll pumps through the YBM turbo pump.  Pumpdown was done for about 2 hours taking us down to 340 Torr.  The pumpdown was stopped at 7:02 pm local time for the night.

No issues to report during the startup of the pumpdown, however something to note is that during the blow down of the vacuum envelope the system was not pressurized, last minute work on the different chambers did not allowed to pressurize the envelope. 

As per WP 13401.  In preparation for upcoming daqd upgrades I'm working to move the run number server off of h1daqscript0 and onto the HA container cluster.  I have the new instance running with the current run number database.  I just need to configure the framewriters to point to it.  I will do that next week.   The run number server helps keep the run number that is put into the frames consistent between the two frame writers.

This is a step to retiring the h1daqscript0 machine once we remove the daqd's px dolphin.

TITLE: 07/09 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Preparations continued today for corner volume pumpdown.
LOG:

A couple days ago I noticed that HAM3 HEPI H4 L4C had almost 0 signal compared to the other L4Cs on that chamber. I didn't have time until this afternoon to look at it. L4C proof masses can get stuck (or something) so I tried waking it up by tapping on the L4C casing or (gently) slapping the locked crossbeam. Neither seemed to work, so I powered off the interface chassis on the pier, and swapped the cables between the H4 and V4 L4C. This seemed to work. The H4 L4C still worked when I swapped the cables back. Probably need to watch this down the road, maybe think about adding a famis task to monitor, because this is the second "stuck" L4C I've found on the IMC HAMs.

Matt, Sophie, Camilla

CHETA uses a Linear translation stage with a 100mm range. +50mm is moving L2 upstream (towards M3), -50mm is moving downstream (towards M4).

Currently if a position out of this range is requested, the translation stage becomes frozen. The only way we've found to reset it is to unplug from the chassis and plug into the Newport Driver (ESP300), turn MTR ON and then press home for Axis 1. We are working with the Beckhoff team to hard code limits so this will not happen in the future. 

Chamber side testing of the PSAMS shows that the Strain Gauge (SG) voltage of ZM5 has railed at -28V (which indicates an open circuit.). I am able to drive and measure the PZT voltage from 0 to 200V, however the strain gauge voltage always remains at -28V (strangely the SG resistance still shows the correct 700ohms and 360 ohms values) - so I am not sure how, but perhaps there is some loose connection.

To further confirm this - I tested ZM4 (which shares the chassis with ZM5) and I was able to drive the PZT voltage from 0-200V and correspondingly get SG voltage of 3.5 - 7.7V (which ties up with my previous measurements in performed 2023). To rule out an issue in ZM5 electronics chain I hooked up ZM5 to the healthy electronics chain of ZM4 and repeated the above measurement and still obtained an open circuit for ZM5.

Hence, ZM5 PSAMS is broken and needs immediate replacement. Work to replace PSAMS is currently ongoing.

R. Kumar, C. Compton, R. Short

Rahul is preparing to swap the bottom stage of ZM5 due to a misbehaving strain gauge (see alog90802 and others for details). To "prove to ourselves it's actually broken" and to document how it behaves when broken, Rahul and I decided to exercise the PZT for the ZM5 PSAM by stepping it up from 0V. With the strain gauge servo off, we used the offset slider to step the PZT to 10V, 20V, 50V, then 100V with a 10 second ramptime and watched the strain gauge signal (see first half of time on the attached ndscope screenshot). The strain gauge readback responded as expected until we stepped to 50V, where it jumped back down, and at 100V the readback completely flatlined at -10V. Thinking we maybe made too big of a step, we repeated this process but only doing steps of 10V at a time. Again when reaching 50V on the PZT, the strain gauge jumped, this time all the way down to -9V readback.

This behavior is consistent with our leading theory of a loose contact or broken solder joint somewhere internal to the PZT/strain gauge assembly. As the PZT changes voltage, the mechanical change being made perhaps pulls the lead for the strain gauge loose or otherwise breaks contact with the circuit. We have confirmed "it's definitely broken" and we will move forward with the replacement.

Per FRS 38164, the unused viewport located at A1F1 and A2F1 on HAM7 have been removed and blanked off.  These viewports are being moved to HAM3, so serial number, etc. will be recorded in a separate aLog.

Late entry for VAC - Gerardo, Travis, Jordan, Tyler and Randy put the doors on HAM3 yesterday afternoon.  They did -Y first, then +Y.  Getting the doors craned over and transferred to the Forklift could only happen at the corner near the TCSy table, so was a tight fit at that transfer point.

These were the last doors to go on for this vent window.

Well done team.

Ken, Preeti, TJ

We've made transfer functions to see and compare the level of cross coupling between P and Y at both sites for the top stage of BBSS. The L1 traces were rescaled to match the H1 magnitude for the PtoP comparison at 0.1Hz. The scaling factor was 3.72. This was done to compensate for the DAC differences between the sites. All of the L1 traces were multiplied by this scale factor. All plots are found in the attached PDF. 

Jim, Ryan S, Dave:

we installed a new h1seiproc model which required a DAQ restart.

The new model added:

1108 slow channels

36 fast channels

40 IPC Receivers

Camilla, Gerardo.

For ITMY, we installed CHETA VP D1700340-type02 as planned in A-1F VP3:

• Primary VP sealing optic D1100439-type02 SN 002 0.5" thick AR 1064nm, 10.6um (Coherent)
• Secondary dust-cover optic D1100485-type03 SN 005 0.25" thick AR 1064nm, 4.6um (Edmund Optics)
• This went to plan as was installed in  90917, assy D1700340-type002-003

For ITMX, we did not install a CHETA VP, as we had issues with the primary optic. We instead installed a blank in A-1C VP4 in 90949.

• Secondary dust-cover optic D1100485-type03 SN 001 0.25" thick AR 1064nm, 4.6um (Edmund Optics)
  • Initially when we pulled first contact from this, a ~ 5mm x 5mm piece of the AR coating pulled off. Photos of optic and FC attached. 
  • This is not expected as is our standard ZnSe cleaning procedure. GariLynn said that this could be caused by poor optic cleaning by manufacturers prior to coating. 
  • We then planned to use D1100485-type02 SN 001 0.25" thick AR 1064nm, 10.6um (Coherent) in it's place, but on assembly we found:
• Primary VP sealing optic D1100439-type02 SN 001 0.5" thick AR 1064nm, 10.6um (Coherent)
  • Once this full assembly was together and all first contact pulled, I noticed a dark speck ~0.75" from the edge of the air side of the optic.
  • Dis-assembled, re cleaned and re inspected. Speck seemed to be a small < 1mm x 1mm hole in coating as it appeared dark or light defending on lighting conditions. 
  • I think I would have seen this in the original inspections if it was there so think this coating was also pulled off by first contact. 
  • As this is a vacuum sealing optic, it will not be installed. 

This morning, with Mitch and Shoshana, I went into the nozzle between HAM3 and BSC2, via the HAM3 door to fix the broken H3 actuator. I had to remove a couple baffles to get in and get access to the hatch over the H3 actuator, once the hatch was off, I found the pin on the back of the actuator terminal block had come lose, probably when I was in there to do the CPS upgrade. I probably should have checked this wire after I finished that swap, but it there was no way to see that anything was wrong, I had to grab the wire and pull on it. Once that was reconnected and I put everything back together, we did a quick chamberside test and H3 was driving again. I've now completed close out tfs, attached image, and run a CPS linearity measurement to check the new cpses. The linearity test plots failed in a way that didn't save the data, but I do have the terminal output of the test which agrees with HAM7: 

  'Actuator H1 to  CPS H1'

Linear regression y= 1.862 x + 245 

    'Actuator  V1 to  CPS V1'

Linear regression y= 1.890 x + -771 

    'Actuator  H2 to  CPS H2'

Linear regression y= 1.845 x + -271 

    'Actuator  V2 to  CPS V2'

Linear regression y= 5.105 x + 2771 

    'Actuator  H3 to  CPS H3'

Linear regression y= 5.073 x + 1543 

    'Actuator  V3 to  CPS V3'

Linear regression y= 5.119 x + 2882 

At some point after doors go on, I will want to try to fix the cps linearity test script and run it again, among the many other measurements I will need for HAM3.

[Jim, Shoshana]

The CRS is currently aligned, suspended, balanced, and unlocked on HAM3!

I aligned each HoQI as well as I could on the table, HoQI2 is slightly better than HoQI1, but it shouldn't be an issue. I also lowered the resonant frequency as much as possible, but I ended up running out of mass that I could easily remove from the bottom, so right now the resonant frequency is at ~25Hz. It's possible this raised frequency is because these flexures (21, 22) might be slightly thicker than the previous ones as they came from a different batch.

Tested the picomotor, moving the X value positive moves the mass to the left (towards HoQI1). We had it do three revolutions in both directions and the picomotor was able to couple with the mass adjuster while at maximum range (tilting fully to either side). We've also discovered that the GS13s outputs go crazy when the picomotor is running, which is something to be aware of.

We've verified that voltage makes it to the damping capacitor plates on either side. We've also confirmed that in the HOQI{1,2}_DIST data increases as the corner cube gets closer to either interferometer (i.e. when the left corner cube (wing) gets closer to HoQI1, the HoQI1_DIST channel data increases)

Attached are various photos of the CRS on the table for future reference, as well as a guide to all the balance masses currently on it.

Filing a late report, last week I measured the resistance of the strain gauge on the PSAMS for ZM5 suspension in HAM7 chamber. This is to investigate the inconsistent behavior (voltage drop/open loop issues) of the strain gauge attached to the PSAMS on ZM5 - details posted in LHO alog 90783.

To measure the resistance of the strain gauge and confirm if anything is broken, I decided to check it chamber side (on the racks in the LVEA). To locate the chassis in the LVEA I referred to the A+ SUS HAM 7 (sush7) System Wiring Diagrams (D2000202_V12), page 04 (ZM5, M2 PSAMS). This document pointed me towards SQZ-R1, Slot U2, where the chassis D2000555 was located. At first, I switched off the chassis and then unplugged cable no 6 which was connected to the JIG Box (J8-Metal PCB Jumper Box DB25 Male female). Then I  connected a breakout board to cable no 6. For measuring the resistance of the strain gauge, I looked into D2000383 to find the correct pins (Camille Makarem (CIT) also talked to the vendor and sent me the pin number, as given in E2500225). This is as follows,

700 Ohms between Ex+ and Ex-

350 Ohms between signal+ and Ex-.

From the pinouts in https://dcc.ligo.org/LIGO-E2500225, this should be

700 Ohms between pins 1 and pins 3/2

350 Ohms between pins 6 and pins 2/3
 

Chamber side this comes to be pin 12 & 25 and pin 11 & 25. Using a multimeter, I got the following readings,

Pin 12 & 25 = 706 Ohms (looks good)

Pin 11 & 24 = 360.5 Ohms (looks good)

The chassis was powered on after the measurements were complete and cable 06 reconnected to the JIG box and secured using two screws (which were missing). The above measured numbers are as per the strain gauge manufacturer. However, It could be possible that the soldering is coming off and giving us open loop sometimes, if not all times. We will continue to investigate this issue and if we are not able to fix it then the plan is to replace it with a spare unit. A spare ZM5 PSAMs unit is currently being prepared by Camille Makarem and should be shipped to LHO within a day or two. We will then start working on swapping out the faulty unit with spare one, in-situ.  

After this week's HAM3 CPS work, had been hearing "HAM3 CPS Glitch" verbal alarms every few seconds, so volume reduced on Verbal.  To allow us to hear Verbal, RyanS made an edit to the tests.py file to remove the alarm for HAM3's CPS Glitches (he commented this change in the file). 

This specific alarm will need to be restored--after the CPS work is complete.

Mitchell, Rahul

This morning we entered HAM3 chamber and attached the baffles (for stray light control) to both PR2 (HSTS) and MC2 (HSTS) suspensions. The baffle assembly design is shown D1700257_V5. These baffles were attached (directly mounted on the HSTS structure) on both the sides of the optic, i.e  HR and AR side.

Before attaching the baffles I inspected both the optics and they looked nice and clean, hence didn't needed any First Contact cleaning. 

I am attaching pictures below for reference.

We found that both PR2 and MC2 had two missing 1/4-20 threads on the HR side for attaching the mounting rail (D1700249_v1) of the baffle (Mitchell will attach a picture showing the same). Typically, these rail need four holes on the structure for securing them. However, we used the lower two threaded holes for attaching these mounting rail and they were rigidly secured. On the DCC I found that both PR2 and MC2 have D020023_V3 of the HSTS_Structural Weldment Assembly, latest D020023_V7 has more holes on the frame.

We also noted that one of the Siskiyou mount is very close to the MC2 baffle (AR side) as shown in the picture here. However, I can confirm that they are not touching and there is a decent amount of clearance between them. 

I still need to perform health checks on both the suspensions to rule out any rubbing and will post the results as a comment over here.

Note - counts on dust monitor were in single digit before and after entering/exiting the chamber (Thanks to Ryan C for arranging this). 

Due to a mistake in past CHETA models there is more astigmatism then expected on the tables and a change in beam size at the ITM. The astigmatism can be fixed by rotating L1 around the vertical axis and the beam size can be changed by movind L2 using the translation stage in each setup. Using a modified Fintrace model the required rotation angle and translation for each table  as they are currently populated at LHO (0922, 0918) and LLO (0919, 0851) have been calculated and are shown below. 
The tables below give the current astigmatism and then the angles and translations such that the x and y beamsize on the ITM is 52.7mm with no astigmatism. 

This code is avaliable in the CHETA modelling repository.

Without translating of L2 astigmatism can be removed but the beam size is still unoptimised.