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New entries since:Wed Dec 31 16:00:00 1969
ID Date Author Typeup Category Subject
  16495   Thu Dec 9 00:32:56 2021 TegaUpdateCDSNew SUS medm screen update

The new SUS screen can be reached via sitemap -> IFO SUS button -> NEW ETMX dropdown menu link. Please use and provide feedback. Not sure exactly if we need/want the display screens after the IOP model on the right of the medm screen. I have not been able to locate the corresponding channels but did not want to remove them until I was sure that we don't plan to add these features to our screens. When all bugs have been ironed out, we can use appropriate macro substitution for the other optics.

The next feature to add is the BLRMS to the coil and PD channels. I plan to combine the PEM BLRMS medm implementation with the sus_single_BLRMS model block (located in  /opt/rtcds/userapps/release/cds/c1/models). This way we use the latest BLRMS block in "/opt/rtcds/userapps/release/cds/common/models/BLRMS.mdl" whilst also leveraging the previous work done on the sus_single_BLRMS model, which neatly fits into our current SUS model.

Attachment 1: Screen_Shot_2021-12-09_at_12.29.30_AM.png
Screen_Shot_2021-12-09_at_12.29.30_AM.png
Attachment 2: Screen_Shot_2021-12-09_at_12.42.35_AM.png
Screen_Shot_2021-12-09_at_12.42.35_AM.png
  16496   Thu Dec 9 18:22:36 2021 TegaUpdateCDSNew SUS medm screen update

Work on the medm screen for SUS RMS monitor is ongoing. The next step would be to incorporate this into the SUS medm screen, add the BLRMS model to the SUS controller model, recompile, check that the channels are being correctly addressed, then load the appropriate bandpass and lowpass filters.  

Attachment 1: Screen_Shot_2021-12-09_at_6.21.09_PM.png
Screen_Shot_2021-12-09_at_6.21.09_PM.png
  16497   Thu Dec 9 21:57:35 2021 YehonathanUpdateBHDSOS assembly

{Yehonathan, Tega}

We took the optic out of the SOS tower and removed the side blocks. We mounted new side blocks with wires already clamped in them in the reverse order.

The Adapter was placed back into the SOS and the wires were threaded through the wire clamp and suspended on the winches. The roll of the optic was balanced using a camera (attachment 1).

The pitch was balanced. this time I used 2 counterweights instead of 1 in order to not have to take so much of the weight out.

The mechanical resonances were measured by taking a 100 sec time series of QPD readout and doing PSD estimation (attachment 2). The mirror motion was damped as much as possible before taking the measurement.

3 peaks below 1.5Hz can be seen with frequencies of 755mHz (Yaw), 942mHz, 1040mHz (Pitch + Pos). The pitch/pos peaks are a bit close to each other, I bet if we go back to 1 counterweight the situation will be better.

While inserting the side OSEM I realized I didn't check the overall height of the adapter. The magnet was too high. I will fix it tomorrow and repeat the roll balancing.

 

Attachment 1: balancingsos2.png
balancingsos2.png
Attachment 2: FreeSwingingSpectra.pdf
FreeSwingingSpectra.pdf
  16499   Fri Dec 10 15:59:23 2021 PacoUpdateBHDFinished Coil driver (even serial number) units tests

[Paco, Anchal]

We have completed modifications and testing of the HAM Coil driver D1100687 units with serial numbers listed below. The DCC tree reflects these changes and tests (Run/Acq modes transfer functions).

SERIAL # TEST result
S2100608 PASS
S2100610 PASS
S2100612 PASS
S2100614 PASS
S2100616 PASS
S2100618 PASS
S2100620 PASS
S2100622 PASS
S2100624 PASS
S2100626 PASS
S2100628 PASS
S2100630 PASS
S2100632 PASS
S2101648** FAIL (Ch1, Ch3 run mode)
S2101650** FAIL (Ch3 run mode)
S2101652** PASS
S2101654** PASS

** A fix had to be done on the DC power supply for these. The units' regulated power boards were not connected to the raw DC power, so the cabling had to be modified accordingly (see Attachment #1)

Attachment 1: dc_fail.jpg
dc_fail.jpg
  16500   Fri Dec 10 18:55:58 2021 TegaUpdateCDSNew SUS medm screen update

Turns out the BLRMS monitoring channels for MC1, MC2, MC3, ITMY and SRM already exist in c1pem. So I modified the new SUS screen to display the BLRMS info for the aforementioned optics. Next step is to add the BLRMS monitor for PRM, ITMX, ETMX and ETMY. This would require extending the number of inputs for the "SUS" block in c1pem to accomodate the additional inputs from the remaining optics.

Attachment 1: BLRMS_ITMY_screenshot.png
BLRMS_ITMY_screenshot.png
  16501   Fri Dec 10 19:22:01 2021 KojiUpdateVACPumping down the RGA section

The scan result was ~x10 higher than the previously reported scan on 2020/9/15 (https://nodus.ligo.caltech.edu:8081/40m/15570), which was sort of high from the reference taken on 2018/7/18.

This just could mean that the vacuum level at the RGA was x10 high.
We'll just go ahead with the vacuum repair and come back to the RGA once we return to "vacuum normal".

Meanwhile, I asked Jordan to turn off the RGA to make it cool down. I shut off RGA section and turned TP2 off.

  16503   Mon Dec 13 15:05:47 2021 TegaUpdatePEMgit repo for temp sensor and sus medm

[temperature sensor]

git repo: https://git.ligo.org/40m/tempsensor.git

todo

Update the temp sensor channels to fit with cds format, ie. "C1:PEM-TEMP_EX", "C1:PEM-TEMP_EY", "C1:PEM-TEMP_BS"

- Use FLOAT32_LE data format for the database file (/cvs/cds/caltech/target/c1pem1/tempsensor/C1PEMaux.db) to create the new channels.

- Keep the old datadase code and channels so we can compare with new temp channels afterwards. Also we need a 1-month overlap b4 deleting the old channels.

 

[sus medm screen]

git repo: https://git.ligo.org/40m/susmedmscreen.git

todo (from talk with Koji)

- Link stateword display to open "C1CDS_FE_STATUS.adl"

- Damp filter and Lock filter buttons should open a 3x1 filter screen so that the 6 filters are opened by 2 buttons compared to the old screen that has 3 buttons connected to 2X1 filter screen

- Make the LOCKIN signla modulation flow diagramlook more like the old 40m screen since that is a better layout

- Move load coefficient button to top of sus medm screen (beside stateword)

- The rectangular red outline around the oplev display is confusing and needs to be modified for clarity

- COMM tag block should not be 3D as this suggests it is a button. Make it flat and change tag name to indicate individual watchdog control as this better reflect its functionality. Rename current watchdog switch to watchdog master is it does what the 5 COMM switches do at once.

- Macro pass need to be better documented so that when we call the sus screens from locations other than sitemap, we should know what macro variables to pass in, like DCU_ID etc.

- Edit sitemap.adl to point only to the new screens. Then create a button on the new screen that points to the old screen. This way, we can still access the old screen without clogging sitemap.

- Move the new screen location to a subfolder of where the current sus screens reside, /opt/rtcds/userapps/trunk/sus/c1/medm/templates

- Rename the overview screen (SUS_CUST_HSSS_OVERVIEW.adl) to use the SUS_SINGLE nomenclature, i.e. SUS_SINGLE_OVERVIEW.adl

- Keep an eye of the cpu usage of c1pem as we add BLRMS block for other optics. 

 

 

  16504   Tue Dec 14 11:33:29 2021 TegaUpdatePEMgit repo for temp sensor and sus medm

[Temperature sensor]

Added new temp EPICs channels to database file (/cvs/cds/caltech/target/c1pem1/tempsensor/C1PEMaux.db)

Added new temp EPICs channels to slow channels ini file (/opt/rtcds/caltech/c1/chans/daq/C0EDCU.ini)

 

[SUS medm screen]

Moved new SUS screen to location : /opt/rtcds/userapps/trunk/sus/c1/medm/templates/NEW_SUS_SCREENS

Place button on the new screen to link to the old screen and replace old screens link on sitemap.

Fixed Load Coefficient button location issue

Fixed LOCKIN flow diagram issue

Fixed watchdog labelling issue

Linked STATE WORD block to FrontEnd STATUS screen

Replaced the 2x1 pit/yaw filter screens for LOCK and DAMP fliters with 3x1 LPY filter screen

*Need some more time to figure out the OPTLEV red indicator

  16505   Tue Dec 14 14:02:33 2021 YehonathanUpdateBHDSOS assembly

{Yehonathan, Paco}

I fixed the overall height of the adapter (attachment 1). I put an OSEM next to the side magnet. I positioned a camera in front of the SOS and connected it to my laptop for live streaming. I painted a line indicating the height of the OSEM plates and a line in between with the mean height. I discarded the wire clamp on the suspension block I released the wires from the winches and pulled on them until the magnet was roughly in the right position. I clamped the wires back on the winches and adjusted them until the magnet was on the middle line. I also verified that the roll of the adapter is aligned as before by making sure that the horizontal features on the adapter are parallel to the horizontal features on the SOS tower.

The wires were clamped to the suspension block using a new wire clamp.

I Found that locking the counterweight setscrew changes the alignment. Today we verified this effect. We released the setscrew and pre-compensated by adjusting the counterweight such that when the setscrew was locked the mirror was aligned.

We measured mechanical resonances (attachment 2). This time the yaw motion was very quiet so we got a smaller peak for the yaw. The peaks are the same as before. Y readout has peaks around the pitch and pos resonances that don't appear in the X readout. I'm not sure what they are. Maybe coming from the QPD electronics.

We locked the adapter using the EQ stops. We made sure the alignment stays close to ideal.

We installed OSEMs on the SOS. We chose suboptimal OSEMs because LO1 will only be used for steering. I made a spreadsheet copying the OSEM catalog into it. There we mark which OSEM goes where.

I cleaned the optic using the ion gun with a pressure of 30 PSI.

The next steps are:

1. Engrave the SOS tower.

2. Cut the wire at the winches and remove the winch adapter plate.

3. Wrap the SOS with foil.

4. Install the SOS in the vacuum chamber.

 

 

Attachment 1: magnetcentring.png
magnetcentring.png
Attachment 2: FreeSwingingSpectra.pdf
FreeSwingingSpectra.pdf
  16506   Tue Dec 14 19:29:42 2021 PacoUpdateBHD1Y0 rack work for LO1

[Paco]

Two coil drivers have been installed on 1Y0 (slots 6, 7, for LO1 SOS). All connections have been made from the DAC, AI board, DAC adapter, Coil driver, Sat Amp box. Then no SOS load installed, all return connections have been made from Sat Amp box, ADC adapter, AA board, and to ADC. We will continue this work tomorrow, and try to test everything before closing the loop for LO1 suspension.

  16507   Wed Dec 15 13:57:59 2021 PacoUpdateComputersupgraded ubuntu on zita

[Paco]

Upgraded zita's ubuntu and restarted the striptool script.

  16508   Wed Dec 15 15:06:08 2021 JordanUpdateVACVacuum Feedthru Install

Jordan, Chub

We installed the 4x DB25 feedthru flange on the North-West port of ITMX chamber this afternoon. It is ready to go.

  16511   Wed Dec 15 22:09:53 2021 YehonathanUpdateBHDSOS assembly

{Paco, Yehonathan, Anchal}

I cut the wires from the winches and removed the winch adapter plate. I engrave  'LO1' on the SOS tower. Me and Paco wrapped the SOS with foil and transported it to Anchal who put it inside the ITMX chamber.

The transportation seems to be successful. Nothing broke. However, we found that even with the short side OSEM the LO1, as it is now, cannot sit in its designed position since ITMX's side OSEM stands in its way.

If there are magnets on both ITMX sides we can move its side OSEM to the other side. Another option is to resuspend LO1 with a side magnet on its left side.

 

  16512   Thu Dec 16 12:21:16 2021 AnchalUpdateBHDCoil driver test failed for S2100619-v1

Today I found one of the coil driver boards, S2100619 failed the test on CH2. There appears to be an extra phase lag after 10 kHz and some resonant-like feature at 7 kHz. This of course is very high-frequency stuff and maybe we don't care about these deviations. But it could mean something is off with the channel and could potentially lead to failure in the relevant frequency band in the future. I'll need help to debug this. Please see the attachment for details of test failure.

Attachment 1: D1100687_S2100619-v1_TF_CH2_Not_Matching.pdf
D1100687_S2100619-v1_TF_CH2_Not_Matching.pdf D1100687_S2100619-v1_TF_CH2_Not_Matching.pdf
  16513   Thu Dec 16 15:04:12 2021 ChubUpdateElectronicsITMX feedthroughs and in-vac cables installed

The ITMX 10" flange with four DSUB-25 feedthroughs has been install with the cables connected at the in-vac side.  See photo; as requested, LO1-1 and LO1-2 are connected to the top row of feedthroughs from left to right respectively and the opposite ends of the cables placed left to right on the laser table.  PR2-1 and PR2-2 are connected to the lower row of feedthroughs from left to right respectively, with the opposite ends placed on the surface below the laser from left to right.  This seemed the easiest way to keep the cable orientation clear.

Attachment 1: ITMX_feedthrough_install_12-16-21.jpg
ITMX_feedthrough_install_12-16-21.jpg
  16514   Thu Dec 16 15:32:59 2021 AnchalUpdateBHDFinished Coil driver (odd serial number) units tests

We have completed modifications and testing of the HAM Coil driver D1100687 units with serial numbers listed below. The DCC tree reflects these changes and tests (Run/Acq modes transfer functions).

SERIAL # TEST result
S2100609 PASS
S2100611 PASS
S2100613 PASS
S2100615 PASS
S2100617 PASS
S2100619 FAIL (CH2 phase)
S2100621 PASS
S2100623 PASS
S2100625 PASS
S2100627 PASS
S2100629 PASS
S2100631 PASS
S2100633 Waiting for more components
S2101649** PASS
S2101651** PASS
S2101653** PASS
S2101655** PASS

** A fix had to be done on the DC power supply for these. The units' regulated power boards were not connected to the raw DC power, so the cabling had to be modified accordingly.

Further, Paco fixed the two even serial number units (S2101648, S211650) that failed the test. The issues were minor soldering mistakes that were easily resolved.

  16515   Thu Dec 16 15:54:08 2021 KojiUpdateElectronicsITMX feedthroughs and in-vac cables installed

Thanks for the installation.

With regard to the connector convention, let's use the attached arrangement so that it will be consistent with the existing flange DSUB configuration. Not a big deal.

 

Attachment 1: PXL_20211216_235056582.jpg
PXL_20211216_235056582.jpg
  16516   Thu Dec 16 17:41:12 2021 KojiUpdateBHDCoil driver test failed for S2100619-v1

Good catch. It turned out that the both + and - side of the output stages for CH2 were oscillating at ~600kHz. If I use a capacitance sticks to touch arbitrarily around the components, it stops their oscillation and they stay calm.
It means that the phase margin becomes small while the circuit starts up.

I decided to increase the capacitances C6 and C20 (WIMA 150pF) to 330pF (WIMA FPK2 100V) and the oscillation was tamed. 220pF didn't stop them. After visually checked the signal behavior with an oscilloscope, the unit was passed to Anchal for the TF test.

The modification was also recorded in the DCC S2100619

Attachment 1: PXL_20211217_001735762.jpg
PXL_20211217_001735762.jpg
Attachment 2: PXL_20211217_001719345.jpg
PXL_20211217_001719345.jpg
Attachment 3: PXL_20211217_005344828.jpg
PXL_20211217_005344828.jpg
Attachment 4: PXL_20211217_010131027.PORTRAIT.jpg
PXL_20211217_010131027.PORTRAIT.jpg
Attachment 5: PXL_20211217_011423823.jpg
PXL_20211217_011423823.jpg
Attachment 6: HAMA_Driver_V4.pdf
HAMA_Driver_V4.pdf
  16517   Thu Dec 16 17:57:17 2021 AnchalUpdateBHDFinished Coil driver (odd serial number) units tests

S2100619 was fixed by Koji and it passed the test after that.

Quote:
SERIAL #  
S2100619 FAIL (CH2 phase)

 

  16518   Thu Dec 16 18:16:36 2021 YehonathanUpdateBHDSOS assembly

Today I glued magnets onto the new 3/4" mirror adapters. I also took the opportunity to make some more side magnets assemblies.

Yesterday I mounted PR3/SR2 3/4" thick mirror onto one of the new adapter. There seem to be no issues for now.

I started the process of suspending AS1 (E2000226-A). The Lambda Optic mirror with the closest specs has Rc = 2 m. I attached side blocks with clamped wires onto adapter number 7 - side block with a magnet on the right.

I then took one of the Lambda Optic mirrors and tried mounting it in the adapter. It was quite difficult to get it right. Unfortunately, I chipped the edge of the substrate (attachment 1) 🤦🏻‍♂️. I put the mirror back in the box and decided to use the spare mirror. I successfully mounted it into the adapter but when I put the clamping screws one of them fell on the mirror 🤦🏻‍♂️🤦🏻‍♂️. There is no visible damage though. I took some pictures (attachment 2-4).

I and Anchal then started suspending the mirror but then we found that one of the wires is dented in the middle 🤦🏻‍♂️🤦🏻‍♂️🤦🏻‍♂️. I'm burned out for today.

Late update: one nice thing that I found yesterday is that the glue is viscous enough to hold the dumbells without a metal sheet from above holding the magnets. This greatly simplifies the gluing process.

 

Attachment 1: chippedmirror.png
chippedmirror.png
Attachment 2: IMG_6311.JPG
IMG_6311.JPG
Attachment 3: IMG_6310.JPG
IMG_6310.JPG
Attachment 4: IMG_6309.JPG
IMG_6309.JPG
  16519   Fri Dec 17 12:32:35 2021 KojiUpdateSUSRemaining task for 2021

Anything else? Feel free to edit this entry.

- SUS: AS1 hanging

- SUS: PR3/SR2/LO2 3/4" thick optic hanging

v Electronics chain check (From DAC to the end of the in-air cable / From the end of the in-air cable to the ADC)
[ELOG 16522]

- Long cable installation (4x 70ft)

- In-air cable connection to the flange

- In-vac wiring (connecting LO1 OSEMs)

- LO1 OSEM insertion/alignment

- LO1 Damping test

 

  16520   Fri Dec 17 17:50:17 2021 YehonathanUpdateBHDSOS assembly

I threaded a new wire through a different side block with a magnet and clamped it under a microscope. It was hard, but eventually, I was able to do it by holding the wire on both sides of the side block with weights.

The dented wire was discarded and the side block that was mounted on the AS1 adapter was put aside. I mounted the side block with the new wire on the AS1 adapter.

 

Anchal and I hanged the AS1 adapter and clamped the wires on the winches of an SOS tower. I balanced the roll and adjusted the height of the magnet with respect to a side OSEM using a camera (attachments 1 & 2).

I shoot the Hene laser on the optic and look at the reflection. I align the laser beam to be as close as possible to the center of the mirror. The OpLev needs to be realigned.

To my surprise, the ghost beam shoots up above the reflected beam! See attachment 3. I check to see that the arrow which marks the thinnest side of the mirror is horizontal (attachment 4). WTF?!

Also, now I realize that the marking on the Lambda optics are pencil markings 😵😵😵.

Attachment 1: AS1rollbalance.png
AS1rollbalance.png
Attachment 2: AS1Magnet_height.png
AS1Magnet_height.png
Attachment 3: ghostbeam.png
ghostbeam.png
Attachment 4: lambdaopticarrow.jpg
lambdaopticarrow.jpg
  16521   Fri Dec 17 19:16:45 2021 KojiUpdateBHDSOS assembly

We @40m do the convention of the arrow at the thinnest side & pointing the HR side, but nobody says Lambda does the same.

We can just remount the mirror without breaking the wires and adjust the pitching if you do it carefully.

Does this mean that the LO1 also likely to have the wedge pointing up? Or did you rotate the mirror to have the wedge reflection to be as horizontal as possible?

  16522   Fri Dec 17 19:19:42 2021 KojiUpdateSUSRemaining task for 2021

I had the fear that any mistake in the electronics chain could have been the show stopper.

So I quickly checked the signal assignments for the ADC and DAC chains.

I had initial confusion (see below), but it was confirmed that the electronics chains (at least for LO1) are correct.

Note: One 70ft cable is left around the 1Y0 rack

 


There are a few points to be fixed:

- It looks like the ADC/DAC card # assignment has been messed up.

CDS ADC0 -> Cable label ADC1 -> AA A1 -> ...
CDS ADC1 -> Cable label ADC0 -> AA A0 -> ...
CDS DAC0 -> Cable label DAC2 -> AI D2 -> ...
CDS DAC1 -> Cable label DAC0 -> AI D0 -> ...
CDS DAC2 -> Cable label DAC1 -> AI D1 -> ...
(What is going on here... please confirm and correct as they become straight forward)

Once this puzzle was solved I could confirm reasonable connections from the end of the 70 cables to the ADC/DAC.

- We also want to change the ADC card assignment. The face OSEM readings must be assigned to ADC1 and the side OSEM readings to ADC0.
  My system wiring diagram needs to be fixed accordingly too.
  This is because the last channel of the first ADC (ADC0) is not available for us and is used for DuoTone.

Attachment 1: PXL_20211218_030145356.MP.jpg
PXL_20211218_030145356.MP.jpg
  16523   Fri Dec 17 22:16:07 2021 YehonathanUpdateBHDSOS assembly

I specifically checked the specification before mounting the mirror. It says clearly "Arrow at the thinnest location pointing towards Side 1". I guess they just ignored it.

As for LO1, I mounted it without noticing the location of the arrow. Later, I checked and the ghost beam was horizontal so I left it as it is. Yeah, I guess I will remount the mirror. Also, what do we do with the pencil markings? It's not vacuum-compatible.

Quote:

We @40m do the convention of the arrow at the thinnest side & pointing the HR side, but nobody says Lambda does the same.

We can just remount the mirror without breaking the wires and adjust the pitching if you do it carefully.

Does this mean that the LO1 also likely to have the wedge pointing up? Or did you rotate the mirror to have the wedge reflection to be as horizontal as possible?

 

  16524   Sat Dec 18 00:56:14 2021 KojiUpdateBHDSOS assembly

Sad... We just need to check the wedge direction everytime, unfortunately.

Pencil: can you try to gently wipe it off with solvent & a swab? (IPA / Acetone)
If it does not come off in the end, it's all right to leave. Do we want to scribe the arrow mark? You need a diamond pen.

  16525   Sun Dec 19 07:52:51 2021 AnchalUpdateSUSRemaining task for 2021

The I/O chassis reassigns the ADC and DAC indices on every power cycle. When we moved it, it must have changed it from the order we had. We were aware of this fact and decided to reconnect the I/O chassis to AA/AI to relect the correct order. We forgot to do that but this is not an error, it is expected behavior and can be solved easily.

Quote:

I had the fear that any mistake in the electronics chain could have been the show stopper.

So I quickly checked the signal assignments for the ADC and DAC chains.

I had initial confusion (see below), but it was confirmed that the electronics chains (at least for LO1) are correct.

Note: One 70ft cable is left around the 1Y0 rack

 


There are a few points to be fixed:

- It looks like the ADC/DAC card # assignment has been messed up.

CDS ADC0 -> Cable label ADC1 -> AA A1 -> ...
CDS ADC1 -> Cable label ADC0 -> AA A0 -> ...
CDS DAC0 -> Cable label DAC2 -> AI D2 -> ...
CDS DAC1 -> Cable label DAC0 -> AI D0 -> ...
CDS DAC2 -> Cable label DAC1 -> AI D1 -> ...
(What is going on here... please confirm and correct as they become straight forward)

Once this puzzle was solved I could confirm reasonable connections from the end of the 70 cables to the ADC/DAC.

- We also want to change the ADC card assignment. The face OSEM readings must be assigned to ADC1 and the side OSEM readings to ADC0.
  My system wiring diagram needs to be fixed accordingly too.
  This is because the last channel of the first ADC (ADC0) is not available for us and is used for DuoTone.

 

  16526   Mon Dec 20 13:52:01 2021 KojiUpdateBHDSOS assembly

LO1: No need to remove the pencil mark for the damping test. Until we see serious contamination on the LO1 optic, we don't need to take the optic off from the mount and clean it. If there is a chance of rehanging (because of a broken wire/etc), we do wipe the pencil mark.

Other optics: wipe the pencil mark as much as possible.

  16527   Mon Dec 20 14:10:56 2021 AnchalUpdateBHDAll coil drivers ready to be used, modified and tested

Koji found some 68nF caps from Downs and I finished modifying the last remaining coil driver box and tested it.

SERIAL # TEST result
S2100633 PASS

With this, all coil drivers have been modified and tested and are ready to be used. This DCC tree has links to all the coil driver pages which have documentation of modifications and test data.

  16528   Mon Dec 20 17:26:13 2021 YehonathanUpdateBHDSOS assembly

{Yehonathan, Anchal}

I released the AS1 wires from the winches, removed the adapter from the SOS tower, and removed the Lambda optic from the adapter. Attachment 1 shows the pencil markings on the optic before cleaning. I cleaned the pencil marking from the side of the optic with acetone using swabs until there were no pencil residues on the swab (attachment 2 shows the swab I used next to an unused swab). I was not able to remove the markings completely though (attachment 3).

I remounted the optic with the arrow rotated by 90 degrees counterclockwise.

We hang the adapter on the winches and adjust the height of the magnet and the adapter roll using the winches. We monitor the height of the adapter using a live stream from the Cannon camera. The camera's tilt was adjusted using straight features on the SOS tower. When we ran out of winch travel we adjust the height using the lower EQ stops and pull tight the wires. Attachment 4 shows the alignment of the side magnet with respect to the SOS tower and a side OSEM.

We checked the ghost beam trajectory and it looks much better (attachment 5)

We started realigning the OpLev. We realize that the height of the beam should be 5+14/32" = 5.437 by measuring the height of the screw holding the side OSEM from the table. The real height from the schematics is 5.425 We make the beam parallel with the table first using an iris and then the QPD.

Today, I balanced the counterweight. First using an iris, then by placing a QPD close to the SOS measuring the reflection from AS1. I locked the counterweight's set screw and the QPD Y readout looks good. Attachment 6 shows the QPD y readout near the beat node between pitch and pos. The node comes very close to zero which indicates that the pitch is balanced.

I measured the free-swinging motion using the QPD x and y axes. Attachment 7 shows the spectra of that motion. The major peaks are at 755mHz, 953mHz, and 1.05Hz.

 

Attachment 1: IMG_6312.JPG
IMG_6312.JPG
Attachment 2: IMG_6315.JPG
IMG_6315.JPG
Attachment 3: IMG_6314.JPG
IMG_6314.JPG
Attachment 4: AS1adapterbalancing.png
AS1adapterbalancing.png
Attachment 5: as1ghostbeam2.png
as1ghostbeam2.png
Attachment 6: beat.png
beat.png
Attachment 7: FreeSwingingSpectra.pdf
FreeSwingingSpectra.pdf
  16529   Tue Dec 21 16:35:39 2021 KojiUpdateVACITMX NW feedthru (LO1-1) connector pin bent

I've received a report that a pin of an ITMX NW feedthru connector was bent. (Attachment 1)
The connector is #1 (upper left) and planned to be used for LO1-1.

This is Pin25 and used for the PD K of OSEM #1. This means that Coil Driver #1 (3 OSEMs) uses this pin, but Coil Driver #2 (2 OSEMs) does not.

Anyways, I tried to fix it by bending it back. WIth some tools, it was straightened enough for plugging the cable connector. (Attachment 2)

It seemed that the pins were exceptionally soft compared to the ones used for usual DSUBs, probably because of the vacuum compatibility.
So it's better to approach the pins in parallel to the surface and not apply mating pressure until you are sure that all the 25pins are inserted in the counterpart holes.

Attachment 1: PXL_20211222_002019620.jpg
PXL_20211222_002019620.jpg
Attachment 2: PXL_20211222_003014068.jpg
PXL_20211222_003014068.jpg
  16531   Tue Dec 21 18:04:46 2021 YehonathanUpdateBHDSOS assembly

I locked the EQ stops while retaining the XY alignment on the QPD and installed 5 green OSEMs. AS1 is ready for transfer into the vacuum chamber.

  16532   Wed Dec 22 14:57:05 2021 KojiUpdateGeneralchiara local backup

chiara local backup of /cvs/cds has not been running since the move of chiara in Nov 19. The remote backup has not been taken since 2017.
The lack of the local backup was because of the misconfiguration of /etc/fstab.

It was fixed and now the backup disk was mounted. We'll see the backup script running tomorrow morning.
The backup disk is smaller than the main disk. So sooner or later, we will face the backup problem again.


localbackup script was crying because there was no backup disk.

backup>pwd
/opt/rtcds/caltech/c1/scripts/backup
backup>tail localbackup.log
2021-12-18 07:00:02,002 INFO       Updating backup image of /cvs/cds
2021-12-18 07:00:02,002 ERROR      External drive not mounted!!!
2021-12-19 07:00:01,146 INFO       Updating backup image of /cvs/cds
2021-12-19 07:00:01,146 ERROR      External drive not mounted!!!
2021-12-20 07:00:01,255 INFO       Updating backup image of /cvs/cds
2021-12-20 07:00:01,255 ERROR      External drive not mounted!!!
2021-12-21 07:00:01,361 INFO       Updating backup image of /cvs/cds
2021-12-21 07:00:01,361 ERROR      External drive not mounted!!!
2021-12-22 07:00:01,469 INFO       Updating backup image of /cvs/cds
2021-12-22 07:00:01,470 ERROR      External drive not mounted!!!

fstab had no entry for the backup disk.

backup>cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    nodev,noexec,nosuid 0       0
# / was on /dev/sda1 during installation
UUID=972db769-4020-4b74-b943-9b868c26043a /               ext4    errors=remount-ro 0       1
# swap was on /dev/sda5 during installation
UUID=a3f5d977-72d7-47c9-a059-38633d16413e none            swap    sw              0       0

# OLD BACKUP DISK
#UUID="90a5c98a-22fb-4685-9c17-77ed07a5e000"    /media/40mBackup       ext4      defaults,relatime,commit=60       0         0

# CURRENT BACKUP DISK as of 2021/09/02
#UUID="1843f813-872b-44ff-9a4e-38b77976e8dc"    /media/40mBackup       ext4      defaults,relatime,commit=60       0         0

#fb:/frames      /frames nfs     ro,bg

# CURRENT MAIN DISK as of 2021/09/02
# UUID=92dc7073-bf4d-4c58-8052-63129ff5755b   /home/cds    ext4    defaults,relatime,commit=60    0   0
UUID="1843f813-872b-44ff-9a4e-38b77976e8dc"   /home/cds    ext4   defaults,relatime,commit=60    0   0

Checked the dev name of the disks and the UUIDs

backup>sudo lsblk
[sudo] password for controls:
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda      8:0    0 465.8G  0 disk
├─sda1   8:1    0 446.9G  0 part /
├─sda2   8:2    0     1K  0 part
└─sda5   8:5    0  18.9G  0 part [SWAP]
sdb      8:16   0   5.5T  0 disk
└─sdb1   8:17   0   5.5T  0 part /home/cds
sdc      8:32   0   3.7T  0 disk
└─sdc1   8:33   0   3.7T  0 part
sr0     11:0    1  1024M  0 rom
backup> sudo blkid
/dev/sda1: UUID="972db769-4020-4b74-b943-9b868c26043a" TYPE="ext4"
/dev/sda5: UUID="a3f5d977-72d7-47c9-a059-38633d16413e" TYPE="swap"
/dev/sdb1: UUID="1843f813-872b-44ff-9a4e-38b77976e8dc" TYPE="ext4"
/dev/sdc1: UUID="92dc7073-bf4d-4c58-8052-63129ff5755b" TYPE="ext4"

Added the fstab entry for the backup disk

media>cat /etc/fstab
# /etc/fstab: static file system information.
#
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    nodev,noexec,nosuid 0       0
# / was on /dev/sda1 during installation
UUID=972db769-4020-4b74-b943-9b868c26043a /               ext4    errors=remount-ro 0       1
# swap was on /dev/sda5 during installation
UUID=a3f5d977-72d7-47c9-a059-38633d16413e none            swap    sw              0       0

# OLD BACKUP DISK
#UUID="90a5c98a-22fb-4685-9c17-77ed07a5e000"    /media/40mBackup       ext4      defaults,relatime,commit=60       0         0

# OLD BACKUP DISK as of 2021/09/02
#UUID="1843f813-872b-44ff-9a4e-38b77976e8dc"    /media/40mBackup       ext4      defaults,relatime,commit=60       0         0

# Current backup disk as of 2021/12/22
UUID="92dc7073-bf4d-4c58-8052-63129ff5755b"    /media/40mBackup       ext4      defaults,relatime,commit=60       0         0

#fb:/frames      /frames nfs     ro,bg

# CURRENT MAIN DISK as of 2021/09/02
# UUID=92dc7073-bf4d-4c58-8052-63129ff5755b   /home/cds    ext4    defaults,relatime,commit=60    0   0
UUID="1843f813-872b-44ff-9a4e-38b77976e8dc"   /home/cds    ext4   defaults,relatime,commit=60    0   0

  16534   Wed Dec 22 18:16:23 2021 KojiUpdateSUSRemaining task for 2021

The in-vacuum installation team has reported that the side OSEMs of ITMX and LO1 are going to be interfering if place LO1 at the planned location.
I confirmed that ITMX has the side magnet on the other side (Attachment 1 ITMX photo taken on 2016/7/21). So we can do this swap.

The ITMX side OSEM is sticking out most. By doing this operation, we will recover most of the space between the ITMX and LO1. (Attachment 2)

Attachment 1: ITMX_2016_07_21.jpg
ITMX_2016_07_21.jpg
Attachment 2: Screen_Shot_2021-12-22_at_18.03.42.png
Screen_Shot_2021-12-22_at_18.03.42.png
  16535   Thu Dec 23 16:38:21 2021 KojiUpdateGeneralIs megatron down? (Re: chiara local backup)

The local backup seems working fine again. But I found that megatron is down and this is a real issue. This should be fixed at the earliest chance.


It seems that the local backup has been successfully taken this morning.

controls@nodus|backup> tail /opt/rtcds/caltech/c1/scripts/backup/localbackup.log
2021-12-19 07:00:01,146 INFO       Updating backup image of /cvs/cds
2021-12-19 07:00:01,146 ERROR      External drive not mounted!!!
2021-12-20 07:00:01,255 INFO       Updating backup image of /cvs/cds
2021-12-20 07:00:01,255 ERROR      External drive not mounted!!!
2021-12-21 07:00:01,361 INFO       Updating backup image of /cvs/cds
2021-12-21 07:00:01,361 ERROR      External drive not mounted!!!
2021-12-22 07:00:01,469 INFO       Updating backup image of /cvs/cds
2021-12-22 07:00:01,470 ERROR      External drive not mounted!!!
2021-12-23 07:00:01,594 INFO       Updating backup image of /cvs/cds
2021-12-23 07:19:55,560 INFO       Backup rsync job ran successfully, transferred 338425 files.

However, I noticed that the autoburt has been stalled since Dec 6 (I used to check how the backup is up-to-date using the autoburt snapshots)

Dec>pwd
/opt/rtcds/caltech/c1/burt/autoburt/snapshots/2021/Dec
Dec>ls -l
total 24
drwxr-xr-x 26 controls controls 4096 Dec  1 23:07 1
drwxr-xr-x 26 controls controls 4096 Dec  2 23:07 2
drwxr-xr-x 26 controls controls 4096 Dec  3 23:07 3
drwxr-xr-x 26 controls controls 4096 Dec  4 23:07 4
drwxr-xr-x 26 controls controls 4096 Dec  5 23:07 5
drwxr-xr-x 19 controls controls 4096 Dec  6 16:07 6

There are a bunch of errors in the log file as follows, but maybe this is not an issue

controls@nodus|burt> pwd
/opt/rtcds/caltech/c1/burt
controls@nodus|burt> tail burtcron.log
!!!  ERROR !!! Target c1supepics Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1tstepics Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1x10epics Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1aux Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1dcuepics Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1iscaux Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1iscepics Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1losepics Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1psl Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1susaux Snapshot file inconsistent with Request file

The real issue seems that megatron is down. It has a lot of house keeping jobs on corn including the N2 pressure alert.
https://wiki-40m.ligo.caltech.edu/Computers_and_Scripts/CRON
This needs to be fixed at the earliest chance.

  16536   Fri Dec 24 16:49:41 2021 KojiUpdateGeneralIs megatron down? (Re: chiara local backup)

It turned out that the UPS installed on Nov 22 failed (cf https://nodus.ligo.caltech.edu:8081/40m/16479 ). As a fact, it was alive just for 2 weeks!

The APC UPS unit indicated F06. According to the manual (https://www.apc.com/shop/us/en/products/APC-Power-Saving-Back-UPS-Pro-1000VA/P-BR1000G), F06 means "Relay Welding" and can not be fixed by a user. Resetting the UPS eliminated the error, but I didn't want to have the same issue while no one is in the lab, I moved the megatron power source from the UPS to the power strip on 1Y7. So, megatron is currently vulnerable to a power glitch.

After the power cords were restored, megatron eventually recovered ssh terminals. I manually ran autoburt.cron at 16:50 so that the latest snapshot is taken.

Attachment 1: PXL_20211224_235652821.jpg
PXL_20211224_235652821.jpg
  16538   Sun Jan 2 20:46:46 2022 KojiUpdateSUSEnd SUS Electronics building

19:00~ Start working on the electronics bench

The following units were tested and ready to be installed. These are the last SUS electronics units and we are now ready to upgrade the end SUS electronics too.

40m End ADC Adapter Unit D2100016 / 2 Units (S2200001 S2200002)

40m End DAC Adapter Unit D2100647/ 2 Units (S2200003 S2200004)

These are placed on Tega's desk together with the vertex DAC adapters

0:30 End work

Attachment 1: PXL_20220103_081133119.jpg
PXL_20220103_081133119.jpg
  16539   Mon Jan 3 12:05:08 2022 PacoUpdateBHD1Y0 rack work for LO2 AS1 AS4

[Paco, Anchal]

Continue working on 1Y0. Added coil drivers for LO2, AS1, AS4. Anchal made additional labels for cables and boxes. We lined up all cables, connected the different units and powered them without major events.

  16540   Mon Jan 3 16:46:41 2022 PacoUpdateBHD1Y1 rack work for SR2, PR2, PR3

[Paco, Anchal]

Continued working on 1Y1 rack. Populated the 6 coil drivers, made all connections between sat amp, AA chassis, DAC, and ADC adapters for SR2, PR2, and PR3 suspensions. Powered all boxes and labeled them and cables where needed. Near the end, we had to increase the current limit on the positive rail sorensen (+18 V) from ~ 7 to > 8.0 Amps to feed all the instruments. We also increased the negative (-18 V) current limit proportionally.

We think we are ready for all the new SOS on this side electronics-wise.


Photos: https://photos.app.goo.gl/GviuqLQviSPo1M3G6

  16541   Tue Jan 4 18:26:59 2022 AnchalUpdateBHDTested 2" PR2 candidates transmission

I used the rejected light from the PBS after the motorized half-wave plate between PMC and IMC injection path (used for input power control to IMC) to measure the transmission of PR2 candidates. These candidates were picked from QIL (QIL/2696). Unfortunately, I don't think either of these mirrors can be used for PR2.

  Polarization Incident Power [mW] Transmitted Power [mW] Transmission [ppm]
V2-2239 & V2-2242 s-pol 940 0.015 16.0
V2-2239 & V2-2242 p-pol 935 0.015 16.0
V6-704 & V6-705 p-pol 925 21 22703

If I remember correctly, we are looking for a 2" flat mirror with a transmission of the order of 1000 ppm. The current PR2 is supposed to have less than 100 ppm transmission which would not leave enough light for LO path.

I've kept the transmission testing setup intact on the PSL table, I'll test existing PR2 and another optic (which is 0.5" thick unfortunately) tomorrow.

  16542   Tue Jan 4 18:27:23 2022 PacoUpdateBHDSOS assembly -- PR3

[yehonathan, paco, anchal]

We continue suspending PR3 today. Yehonathan and Paco suspended the thick optic in its adapter. After fixing some nominal height and undoing any residual roll angle (see Attachments 1,2 for pictures), we noticed a problem with the pitch angle, so we insert the counterweights all the way in. Nevertheless, we soon found out that we needed to shift one of the two counterweights to the back of the adapter side (so one on each side) in order to tare the pitch angle. This is a newly experienced maneuver that may apply for further thick optics.

After taring the pitch angle roughly, we noted another issue. The wedge (~ 1 deg) on the optic made it such that the protruding socket heads on the thick side bumped against the lower clamp (not the earthquake stop tip itself). Attachments #4,5 show the before/after situation which was solved provisionally by replacing the socket head screws with lower profile (flat) head screws in situ. Again, this operation was highly delicate and specific to wedged thick optics, so for future SOS we should keep it in mind.

Another issue that we had with the new thick optic adapters is that for some reason there is a recession in the upper backside of the adapter (attachment coming soon). This makes the upper back EQ stop too short to touch the adapter. We replaced it with a longer screw. When inserted it doesn't really hit the back of the adapter. Rather, it touches the corner of the recession, stoping the optic with friction.

While all this was happening, Anchal started mounting AS4 on its adapter. After one of the magnets broke off, he switched to another one and succeeded. This is the next target for suspension. We still need to check the orientation of the wedge. Furthermore, we started a gluing session in the afternoon to prepare as much as possible for further SOS during the week. 3 side magnets were glued to side blocks. 3 magnets were glued to 3 adapters that were missing 1 magnet each.

In the afternoon, Yehonathan and Paco set up the QPD and did all the usual balancing, and then Anchal took the data of which the result is shown in Attachment #3. The major peaks are located at 723mHz, 953mHz, and 1.05Hz. Very similar to the case of the thin optic adapters.

Anchal progressed with OSEM installation, and engraving and yehonathan glued the counterweight setscrew in place. After securing the EQ stops, and wrapping the wires in foil, we declare PR3 is ready to be installed.

Attachment 1: PR3_roll_balance.png
PR3_roll_balance.png
Attachment 2: PR3_magnet_height.png
PR3_magnet_height.png
Attachment 3: FreeSwingingSpectra.pdf
FreeSwingingSpectra.pdf
Attachment 4: PXL_20220104_231742123.jpg
PXL_20220104_231742123.jpg
Attachment 5: PXL_20220104_232809203.jpg
PXL_20220104_232809203.jpg
  16543   Wed Jan 5 17:46:04 2022 AnchalUpdateBHDTested 2" PR2 candidates transmission

I tested 2 more optics today, the old PR2 that we took out and another optic I found in QIL. Both these optics are also not good for our purpose.

 

Polarization Incident Power [mW] Transmitted Power [mW] Transmission [ppm]
Existing PR2 p-pol 910 0.004 4.4
V2-1698 & V2-1700 p-pol 910 595 653846

I'll find thw Y1S optic and test that too. We should start looking for alternate solutions as well.

 

  16544   Wed Jan 5 19:18:06 2022 YehonathanUpdateBHDSOS assembly -- AS4

{Paco, Yehonathan, Anchal}

Today we suspended AS4 (E2000226-B). Anchal mounted Lambda Optic mirror with an RoC closest to AS4 in a thin optic mount. He noted that this optic as well as AS1 don't have a wedge angle. The specs claim that the wedge angle is 2 degrees what should have been clearly seen by inspecting the optic with a naked eye. All the ghost beam deflections probably come from the curvature of the mirror.

We did all the height and roll balancing using a camera (Attachment 1,2). We balanced that pitch of the adapter using a QPD not before we realigned the OpLev setup.

We measured the motion spectra (attachment 3). Major peaks are found at 755 mHz, 964 mHz, and 1.062Hz. I locked the counterweights setscrew and observed that the pitch balance doesn't change. I locked the EQ stops such that the alignment of the mirror remained the same by monitoring the QPD signals. I clamped the suspensions wires to the suspension block.

The only thing remaining is inserting the OSEMs.

 

Attachment 1: AS4_roll_balance.png
AS4_roll_balance.png
Attachment 2: AS_4_magnet_height.png
AS_4_magnet_height.png
Attachment 3: FreeSwingingSpectra.pdf
FreeSwingingSpectra.pdf
  16546   Thu Jan 6 12:52:49 2022 AnchalUpdateCDSYearly DAQD fix 2022!

Just as predicted, all realtime models reported "0x4000" error. Read the parent post for more details. I fixed this by following the instructions. I add folowing lines to the file /opt/rtcds/rtscore/release/src/include/drv/spectracomGPS.c in fb1:

/* 2020 had 366 days and no leap second */
       pHardware->gpsOffset += 31622400;
/* 2021 had no leap seconds or leap days, so adjust for that */
       pHardware->gpsOffset += 31536000;

Then is made the package and reloaded it after stoping the daqd services. This brought back all the fast models except C1SUS2 models which are in red due to some other reason that I'll investigate further.

 

  16547   Thu Jan 6 13:54:28 2022 KojiUpdateCDSYearly DAQD fix 2022!

Just restarting all the c1sus2 models fixed the issue. (Attachment 1)

SUS2 ADC1 CH21 is saturated. I'm not yet sure if this is the electronics issue or the ADC issue.
SUS2 ADC1 CH10 also has large offset. This should also be investiagted.

Attachment 1: Screenshot_2022-01-06_13-57-40.png
Screenshot_2022-01-06_13-57-40.png
  16548   Thu Jan 6 14:08:14 2022 KojiUpdateCDSMore BHD SUS screens added to sitemap

More BHD SUS screens added to sitemap (Attachment 1)

Attachment 1: Screenshot_2022-01-06_14-06-15.png
Screenshot_2022-01-06_14-06-15.png
  16549   Thu Jan 6 15:10:38 2022 KojiUpdateSUSITMX Chamber work

[Anchal, Koji]

=== Summary ===
- ITMX SD OSEM migration done
- LO1 OSEM insertion and precise adjustment (part 1) done
- LO1 POS/PIT/YAW/SD motions were damped


=== General Remarks ===
- 15:00 Entered into ITMX.
- We were equipped with N95 and took physical distance as much as possible.
- 17:00 Temporarily came out from the lab.
- 18:30? Came into the chamber again
- 20:00 Sus damped. OSEM work continues
- 21:00 OSEM installation work done. Exit.

=== ITMX SD OSEM position swap ===
- Moved the LO1 suspension to the center of the chamber
- Removed the ITMX SD OSEM from the right side (west side) and tried to move it to the other side.
- Noted that the open light output of the ITMX SD was 908 at the output of the SDSEN filter module. So the half-light target is 454. These numbers include the "cnt2um" calibration of 0.36. That means the open light raw ADC count was supposed to be 2522.

- The OSEM set screw (silver plated, with a plunger) was removed from the old position. We first tried to recycle it to the other side, but it didn't go into the thread with fingers. After making ourselves convinced that the threaded hole was identical for both sides, we decided to put the new identical plunger set screw with an Allen-key was used to put it in and it went in!
- Now the ITMX SD OSEM was inserted from the east side. Once we saw some shadow on the OSEM signal, the SD damping was turned on with the previous setting. And this successfully damped the side motion. ⭕️
- A bit finer adjustment has been done. After a few trials, we reached the stable output of ~400. Considering the temporary leveling of the table, we decided this is enough for now ⭕️. The set screw was tightened.
- To make the further work safer w.r.t the ITMX magnets, Anchal fastened the EQ stops of the ITMX sus except for the bottom four.
- Photo: [Attachment 1]

=== LO1 OSEM installation ~ wiring ===
- Now LO1 was moved back to the planned position.
- For the wiring, we (temporarily) clamped the in-vac DSUB cables to the stack table with metal clamps.
- Started plugging the OSEMs into the DSUB cables.
- Looking at the LO1-1 cable from the mating side with the longer side top: The top-right pin of the female connector is Pin1 as usual. From right to left LL / UR / UL coils were inserted one by one while looking at the OSEM PD signals.
- LO1-2 cable has the LR / SD coils (from the right to the left) were connected.
- Photo: [Attachment 2]

- LO1 Open light levels (raw ADC counts) the 2nd number is the target half-light level

  • UL 27679 (-> 13840)
  • UR 29395 (-> 14697)
  • LR 30514 (-> 15257)
  • LL 27996 (-> 13998)
  • SD 26034 (-> 13017)

=== RTS Filter implementation ===

- Anchal copied the filter module settings from other suspensions.
- We also implemented the simple input and output matrices.

=== LO1 OSEM insertion ===

- We struggled to make the suspension freely swinging with the OSEMs inserted.

- It seemed that the magnets were sucked to the OSEMs due to magnetic components.
- It turned out that the OSEMs were not fastened well and not seated in the holder plates.
- Once this was fixeded, we found that the mirror height is too high for the given OSEM heights.
  The suspension height (or the OSEM height should be decided with the OSEMs not inserted but fully fastened to prevent misalignment of them.

- Decided to lift up the OSEM plates in situ.
- Soon we found that the OSEM holder plates are not fastened at all [Attachment 3 arrows]
- The plates were successfully lifted up and
the suspension became much more freely swinging even with the OSEMs inserted. ⭕️

=== LO1 damping and more precise OSEM insertion ===

- Once the OSEMs were inserted to the light level of 30~70%, we started to try to dampen the motion. The side damping was somewhat successful, but the face ones were not.
- We checked the filters and found the coil output filters didn't have the alternating signs.
- Once the coil signs were corrected, the damping became more straight forward.
- And the robust damping allowed us the fine-tuning of the OSEM insertion.

- In the end, what we had for the light levels were

  • UL 14379 (52%)
  • UR 14214 (48%)
  • LR 14212 (47%)
  • LL 12869 (46%)
  • SD 14358 (55%)

The damping is working well. [Attachment 4]


Post continues at 40m/16552.

Attachment 1: PXL_20220107_044739280.MP.jpg
PXL_20220107_044739280.MP.jpg
Attachment 2: PXL_20220107_044958224.jpg
PXL_20220107_044958224.jpg
Attachment 3: PXL_20220107_044805503.NIGHT.jpg
PXL_20220107_044805503.NIGHT.jpg
Attachment 4: Screen_Shot_2022-01-06_at_20.54.04.png
Screen_Shot_2022-01-06_at_20.54.04.png
  16550   Thu Jan 6 17:00:20 2022 YehonathanUpdateBHDSOS assembly -- LO2

{Paco, Yehonathan}

Today we suspended LO2 (E1800089) which Anchal has loaded into the thick optic adapter. Attachments 1,2 show the height and roll balance adjustments.

I realigned the opLev setup and balanced the suspended mass. We figured that if we use 2 counterweights we will be 1 short. We decided to use 1 mass at the back of the adapter. This has the additional advantage that the Viton tip on lower back EQ stop can touch it and act normally. The optic was successfully balanced in this way. Attachment 3 shows the motion spectra on the QPD. There are major peaks at 712 mHz, 854 mHz, 876 mHz, and 996 mHz. As expected using only 1 counterweight raised the center of mass and lowered the pitch resonance frequency. The optic was locked keeping the alignment fixed on the center of the QPD, OSEMs were inserted and the SOS tower was engraved.

We should apply some glue to the counterweight to prevent it from spinning on the setscrew.

Attachment 1: LO2_roll_balance.png
LO2_roll_balance.png
Attachment 2: LO2_magnet_height.png
LO2_magnet_height.png
Attachment 3: FreeSwingingSpectra.pdf
FreeSwingingSpectra.pdf
  16551   Thu Jan 6 17:16:51 2022 YehonathanUpdateBHDUsing Peek screws/nuts

There were several cases where the long EQ stops didn't perform as expected.

In one type of case, we used a counterweight at the front of the adapter but not in the back leaving a recess where the lower back EQ stop should touch.

In the other type, a recess in the thick optics adapter prevented the upper EQ stop from touching the adapter. In the first thick optic, the screw was screw barely scratched the recess' corner. In the second case, it didn't touch it at all.

In the last group meeting, we discussed using Peek screws (made out of plastic) to prevent metal on metal bumping when the EQ can touch the adapter and Peek nuts when it doesn't to increase its impact area.

Mcmaster has 1.5" long 1/4-20 screws (part number 98885A131) that will fit well in the OSEM plates. We can order 20 of those.

The biggest Peek nuts on Mcmaster however are not big enough (7/16" wide) to cover the entire bottom recess area which is 0.5" wide (they are good enough for the top recess area in the thick adapter optic design). Koji suggested that we can use a big Peek washer for that purpose that can be held between nuts. We should then order 10 Peek nuts (98886A813) and 1 package of 10 Peek washers (0.63" OD) (93785A600).

  16553   Thu Jan 6 22:18:47 2022 KojiUpdateCDSSUS screen debugging

Indicated by the red arrow:
Even when the side damping servo is off, the number appears at the input of the output matrix

Indicated by the green arrows:
The face magnets and the side magnets use different ADCs. How about opening a custom ADC panel that accommodates all ADCs at once? Same for the DAC.

Indicated by the blue arrows:
This button opens a custom FM window. When the pitch gain was modified with a ramping time, the pitch and yaw gain grows at the same time even though only the pitch gain was modified.

Indicated by the orange circle:
The numbers are not indicated here, but they are input-related numbers (for watchdogging) rather than output-related numbers. It is confusing to place them here.

Attachment 1: Screen_Shot_2022-01-06_at_18.03.24.png
Screen_Shot_2022-01-06_at_18.03.24.png
ELOG V3.1.3-