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ID Date Author Type Categoryup Subject
  16605   Thu Jan 20 17:03:36 2022 AnchalSummaryBHDPart IV of BHR upgrade - SR2 OSEM tuned.

The main issue with SR2 OSEMs, now that I think of it, was that the BS table was very inclined due to the multiple things we removed (including counterweights). Today the first I did was level the BS table by placing some counterweights in the correct positions. I placed the level in two directions right next to SR2 (clamped in its planned place), and made the bubble center.

While doing do, at one point, I was trying to reach the far South-West end of the table with the 3x heavy 6" cylindrical counterweight in my hand. The counterweight slipped off my hand and fell from the table. See the photo in attachment 1. It went to the bottommost place and is resting on its curved surface.

This counterweight needs to be removed but one can not reach it from over the table. So to remove it, we'll have to open one of the blank flanges on the South-west end of BS chamber and remove the counterweight from there. We'll ask Chub to help us on this. I'm sorry for the mistake, I'll be more careful with counterweights in the future.

Moving on, I tuned all the SR2 OSEMs. It was fairly simple today since the table was leveled. I closed the chamber with the optic free to move and damped in all degrees of freedom.


Photos: https://photos.app.goo.gl/CQ6VouSB1HX2DPqW6


SUSPENSION STATUS UPDATED HERE

Attachment 1: DJI_0144.JPG
DJI_0144.JPG
  16607   Thu Jan 20 17:34:07 2022 KojiUpdateBHDV6-704/705 Mirror now @Downs

The PR2 candidate V6-704/705 mirrors (Qty2) are now @Downs. Camille picked them up for the measurements.

To identify the mirrors, I labeled them (on the box) as M1 and M2. Also the HR side was checked to be the side pointed by an arrow mark on the barrel. e.g. Attachment 1 shows the HR side up

Attachment 1: PXL_20220120_225248265_2.jpg
PXL_20220120_225248265_2.jpg
Attachment 2: PXL_20220120_225309361_2.jpg
PXL_20220120_225309361_2.jpg
  16608   Thu Jan 20 18:16:29 2022 AnchalUpdateBHDAS4 set to trigger free swing test

AS4 is set to go through a free swinging test at 10 pm tonight. We have used this script (Git/40m/scripts/SUS/InMatCalc/freeSwing.py) reliably in the past so we expect no issues, it has a error catching block to restore all changes at the end of the test or if something goes wrong.

To access the test, on allegra, type:

tmux a -t AS4

Then you can kill the script if required by Ctrl-C, it will restore all changes while exiting.

  16609   Thu Jan 20 18:41:55 2022 AnchalSummaryBHDSR2 set to trigger free swing test

SR2 is set to go through a free swinging test at 3 am tonight. We have used this script (Git/40m/scripts/SUS/InMatCalc/freeSwing.py) reliably in the past so we expect no issues, it has a error catching block to restore all changes at the end of the test or if something goes wrong.

To access the test, on allegra, type:

tmux a -t SR2

Then you can kill the script if required by Ctrl-C, it will restore all changes while exiting.

 

  16610   Fri Jan 21 11:24:42 2022 AnchalSummaryBHDSR2 Input Matrix Diagonalization performed.

The free swinging test was successful. I ran the input matrix diagonalization code (/opt/rtcds/caltech/c1/Git/40m/scripts/SUS/InMAtCalc/sus_diagonalization.py) on theSR2 free-swinging data collected last night. The logfile and results are stored in /opt/rtcds/caltech/c1/Git/40m/scripts/SUS/InMAtCalc/SR2 directory. Attachment 1 shows the power spectral density of the DOF basis data (POS, PIT, YAW, SIDE) before and after the diagonalization. Attachment 2 shows the fitted peaks.


Free Swinging Resonances Peak Fits
  Resonant Frequency [Hz] Q A
POS 0.982 340 3584
PIT 0.727 186 1522
YAW 0.798 252 912
SIDE 1.005 134 3365

SR2 New Input Matrix
  UL UR LR LL SIDE
POS
1.09
0.914
0.622
0.798
-0.977
PIT
1.249
0.143
-1.465
-0.359
0.378
YAW
0.552
-1.314
-0.605
1.261
0.118
SIDE
0.72
0.403
0.217
0.534
3.871

The new matrix was loaded on SR2 input matrix and this resulted in no control loop oscillations at least. I'll compare the performance of the loops in future soon.

 

Attachment 1: SR2_SUS_InpMat_Diagnolization_20220121.pdf
SR2_SUS_InpMat_Diagnolization_20220121.pdf
Attachment 2: SR2_FreeSwingData_PeakFitting_20220121.pdf
SR2_FreeSwingData_PeakFitting_20220121.pdf
  16612   Fri Jan 21 14:51:00 2022 KojiUpdateBHDV6-704/705 Mirror now @Downs

Camille@Downs measured the surface of these M1 and M2 using Zygo.

Result of the ROC measurements:M1: ROC=2076m (convex)M2: ROC=2118m (convex)
Here are screenshots. One file shows the entire surface and the other shows the central 30mm.
Attachment 1: M1.PNG
M1.PNG
Attachment 2: M1_30mm.PNG
M1_30mm.PNG
Attachment 3: M2.PNG
M2.PNG
Attachment 4: M2_30mm.PNG
M2_30mm.PNG
  16613   Fri Jan 21 16:40:10 2022 AnchalUpdateBHDAS4 Input Matrix Diagonalization performed.

The free swinging test was successful. I ran the input matrix diagonalization code (/opt/rtcds/caltech/c1/Git/40m/scripts/SUS/InMAtCalc/sus_diagonalization.py) on the AS4 free-swinging data collected last night. The logfile and results are stored in /opt/rtcds/caltech/c1/Git/40m/scripts/SUS/InMAtCalc/AS4 directory. Attachment 1 shows the power spectral density of the DOF basis data (POS, PIT, YAW, SIDE) before and after the diagonalization. Attachment 2 shows the fitted peaks.


Free Swinging Resonances Peak Fits
  Resonant Frequency [Hz] Q A
POS 1.025 337 3647
PIT 0.792 112 3637
YAW 0.682 227 1228
SIDE 0.993 164 3094

AS4 New Input Matrix
  UL UR LR LL SIDE
POS
0.844
0.707
0.115
0.253
-1.646
PIT
0.122
0.262
-1.319
-1.459
0.214
YAW
1.087
-0.901
-0.874
1.114
0.016
SIDE
0.622
0.934
0.357
0.045
3.822

The new matrix was loaded on AS4 input matrix and this resulted in no control loop oscillations at least. I'll compare the performance of the loops in future soon.

 

Attachment 1: AS4_SUS_InpMat_Diagnolization_20220121.pdf
AS4_SUS_InpMat_Diagnolization_20220121.pdf
Attachment 2: AS4_FreeSwingData_PeakFitting_20220121.pdf
AS4_FreeSwingData_PeakFitting_20220121.pdf
  16616   Mon Jan 24 17:12:27 2022 ranaUpdateBHDAS4 Input Matrix Diagonalization performed.

I think our suspension input matrix diagonalization is not so robust usually because we only choose a inverting matrix which gives the best separation for a single suspension alignment.

i.e. we have seen in the past that adjusting the bias for the alignment makes the matrix inversion not work well. Sometime people turn OFF the alignment bias before making the ringdown and that makes the whole measurement invalid.

This is because the sensitivity of the OSEMs to longitudinal and/or transverse motion is significantly different for different alignment.

I wonder if there's a way we can choose a better matrix by putting in random gain errors on the shadow sensor signals and then finding the matrix which gives the best diag under an ensemble of gain errors.

  16617   Mon Jan 24 17:58:21 2022 YehonathanUpdateBHDPR2 Suspension

I picked up the PR2 mirrors (labeled M1, M2) from Anchel's table and took them to the cleanroom. By inspection, I spotted some dust particles on M1. I wasn't able to remove them with clean air so I decided to use M2 which looked much cleaner. I wasn't able to discern any wedge angle on the optic. I inserted the optic into a thin optic adapter. The optic is thicker than I expected so I use long screws for the mirror clamping. I expect that the pitch balance will shift towards the front of the mirror so I assembled only 1 counterweight for now. The side blocks with wires in them were installed.

I engraved the SOS and installed the winches on it. Paco came in and helped me to hang the optic. Looking at the wire hanging angle I realize that 1 counterweight at the front is not enough. I install a second counterweight at the back and observe that I can cross the balancing point.

I locked the EQ stops. Suspension work continues tomorrow...

  16618   Mon Jan 24 18:53:09 2022 AnchalSummaryBHDPart VIII of BHR upgrade - LO2 placed and OSEMs tuned

I placed LO2 in its planned position in BS chamber, inserted the OSEMs, and tuned their position to halfway brightness. At the end of the work, I was able to damp the optic successfully. The full open (full brightness) OSEM ADC counts are:

UL 25743.  -> 12876
UR 27384. -> 13692
LL 25550. -> 12775
LR 27395 -> 13697
SD 28947 -> 14473

Today's OSEM tuning was relatively unhappening. I have only following two remarks:

  • BS table was 3 SOS near the East end and PRM is parked in the center, thus the table is very unevenly balanced. I had to use all available counter weights to make it flat near the LO2 suspension.
  • The side OSEM for LO2 is not exactly centered (probably due to table imbalance). I was able to balance the table to a point though that the side OSEM was responsive to full range and I was able to damp the optic.

Free swinging test set to trigger

LO2 is set to go through a free swinging test at 10 pm tonight. We have used this script (Git/40m/scripts/SUS/InMatCalc/freeSwing.py) reliably in the past so we expect no issues, it has a error catching block to restore all changes at the end of the test or if something goes wrong.

To access the test, on allegra, type:

tmux a -t LO2

Then you can kill the script if required by Ctrl-C, it will restore all changes while exiting.


Photos: https://photos.app.goo.gl/Ff3yGBprj9xgPbnLA

SUSPENSION STATUS UPDATED HERE

  16619   Mon Jan 24 20:48:48 2022 AnchalUpdateBHDAS4 Input Matrix Diagonalization performed.

I agree. That's an interesting idea. But does that mean that there is an always working inverse matrix solution or that any solution will be vulnerable to the alignment biases.

I think we can also calculate the matrix rotation required as a function of dc biases and do that rotation in the simulimk model.

Quote:

I think our suspension input matrix diagonalization is not so robust usually because we only choose a inverting matrix which gives the best separation for a single suspension alignment.

i.e. we have seen in the past that adjusting the bias for the alignment makes the matrix inversion not work well. Sometime people turn OFF the alignment bias before making the ringdown and that makes the whole measurement invalid.

This is because the sensitivity of the OSEMs to longitudinal and/or transverse motion is significantly different for different alignment.

I wonder if there's a way we can choose a better matrix by putting in random gain errors on the shadow sensor signals and then finding the matrix which gives the best diag under an ensemble of gain errors.

 

  16620   Mon Jan 24 21:18:40 2022 PacoSummaryBHDPart IX of BHR upgrade - AS1 placed and OSEM tuned

[Paco]

AS1 was installed in the ITMY chamber today. For this I moved AS4 to its nominal final placement and clamped it down with a single dog clamp. Then, I placed AS1 near the center of the table, and quickly checked AS4 could still be damped. After this, I leveled the table using a heavier/lighter counterweight pair. 

Once things were leveled, I proceeded to install AS1 OSEMs. The LL, UL, UR OSEMs had a bright level of 27000 counts, while SD and LR were at 29500, and 29900 respectively. After a while, I managed to damp all degrees of freedom around the 50% thousand count levels, and decided to stop. 

UL 27000.  -> 16000
UR 27000. -> 13800
LL 27000 -> 14600
LR 29900 -> 14900
SD 29500 -> 12900


Free swinging test set to trigger

AS1 is set to go through a free swinging test at 3 am this evening. We have used this script (Git/40m/scripts/SUS/InMatCalc/freeSwing.py) reliably in the past so we expect no issues, it has a error catching block to restore all changes at the end of the test or if something goes wrong.

To access the test, on allegra, type:

tmux a -t AS1

Then you can kill the script if required by Ctrl-C, it will restore all changes while exiting.


SUSPENSION STATUS UPDATED HERE

  16621   Tue Jan 25 10:55:02 2022 AnchalSummaryBHDPart VIII of BHR upgrade - LO2 input matrix diagonalization performed.

The free swinging test was successful. I ran the input matrix diagonalization code (/opt/rtcds/caltech/c1/Git/40m/scripts/SUS/InMAtCalc/sus_diagonalization.py) on the LO2 free-swinging data collected last night. The logfile and results are stored in /opt/rtcds/caltech/c1/Git/40m/scripts/SUS/InMAtCalc/LO2 directory. Attachment 1 shows the power spectral density of the DOF basis data (POS, PIT, YAW, SIDE) before and after the diagonalization. Attachment 2 shows the fitted peaks.


Free Swinging Resonances Peak Fits
  Resonant Frequency [Hz] Q A
POS 0.981 297 3967
PIT 0.677 202 1465
YAW 0.775 2434 1057
SIDE 1.001 244 4304

LO2 New Input Matrix
  UL UR LR LL SIDE
POS
0.46
1.237
1.094
0.318
0.98
PIT
1.091
0.252
-1.512
-0.672
-0.088
YAW
0.722
-1.014
-0.217
1.519
0.314
SIDE
-0.747
1.523
1.737
-0.534
3.134

The new matrix was loaded on LO2 input matrix and this resulted in no control loop oscillations at least. I'll compare the performance of the loops in future soon.

  16622   Tue Jan 25 11:02:54 2022 AnchalSummaryBHDPart IX of BHR upgrade - AS1 free swing test failed

For some reasonf the free swing test showed only one resonance peak (see attachment 1). This probably happened because one of the earthquake stops is touching the optic. Maybe after the table balancing, the table moved a little over its long relazation time and by the time the free swing test was performed at 3 am, one of the earthquake stops was touching the optic. We need to check this when we open the chamber next.

Attachment 1: AS1_freeSwingTestFailed.pdf
AS1_freeSwingTestFailed.pdf
  16623   Tue Jan 25 16:42:03 2022 AnchalSummaryBHDReduced filter gains in all damped new SOS

I noticed that our current suspension damping loops for the new SOS were railing the DAC outputs. The reason being that cts2um module has not been updated for most optics and thus teh OSEM signal (with the new Sat Amps) is about 30 times stronger. That means our usual intuition of damping gains is too high without applying correct conversion cts2um filter module. I reduced all these gains today and nothing is overflowing the c1su2 chassis now. I also added two options in the "!" (command running drop down menu) in the sus_single medm screens for opening ndscope for monitoring coil outputs or OSEM inputs of the optic whose sus screen is used.

 

  16624   Tue Jan 25 18:37:12 2022 TYehonathanUpdateBHDPR2 Suspension

PR2's side magnet height was adjusted and its roll was balanced (attachment 1,2). I verified that the OpLev beam is still aligned. The pitch was balanced: First, using an iris for rough adjustment. Then, with the QPD. I locked the counterweight setscrew.

I turned off the HEPAs, damped PR2, and measured the QPD spectra (attachment 3). Major peaks are at 690mHz, 953mHz, and 1.05Hz. I screwed back the lower OSEM plate. The wires were clamped to the suspension block and were cut. Winch adapter plate removed. I wanted to push OSEMs into the OSEM plates but the wiki is down so I can't tell what was the plan. This will have to wait for tomorrow. Also here like with AS1 we need to apply glue to the counterweights.

Attachment 1: PR2_magnet_height.png
PR2_magnet_height.png
Attachment 2: PR2_roll_balance.png
PR2_roll_balance.png
Attachment 3: FreeSwingingSpectra_div_50mV.pdf
FreeSwingingSpectra_div_50mV.pdf
  16625   Thu Jan 27 08:27:34 2022 PacoSummaryBHDPart IX of BHR upgrade - AS1 inspection and correction

[Paco]

This morning, I went into ITMY chamber to inspect AS1 after the free swinging test failed. Indeed, as forecasted by Anchal, the top front EQ stop was slightly touching, which means AS1 was not properly installed before. I proceeded by removing it well behind any chance of touching the optic, and did the same for all the other stops, of which most were already recessed significantly. Finally, the OSEMs changed accordingly to produced a PITCHed optic (top front EQ was slightly biasing the pitch angle), so I did a reinstallation until the levels were around the 14000 count region. After damping AS1 relatively quickly, I closed the ITMY chamber.

Quote:

For some reasonf the free swing test showed only one resonance peak (see attachment 1). This probably happened because one of the earthquake stops is touching the optic. Maybe after the table balancing, the table moved a little over its long relazation time and by the time the free swing test was performed at 3 am, one of the earthquake stops was touching the optic. We need to check this when we open the chamber next.

 

  16627   Thu Jan 27 17:57:35 2022 AnchalSummaryBHDPart III of BHR upgrade - Replaced small suspended PR3 with new SOS PR3 and OSEM tuning

[Anchal, Paco]

We removed the old PR3 housed in a tip-tilt style suspension and put it on the North flow bench in the cleanroom. I put PR3 in an accessible position near the North West edge of the BS chamber and balanced the table again with many weights. The OSEM tuning was very uneventful and easy. Following are the full brightness ADC counts for the OSEMs:
UL 25693. -> 12846
UR 24905. -> 12452
LL 23298. -> 11649
LR 24991. -> 12495
SD 26357. -> 13178

I was able to damp the optic easily after the OSEM installation with no issues.


Photos: https://photos.app.goo.gl/jcAqwFJoboeUuR7F9

  16628   Thu Jan 27 18:03:36 2022 PacoSummaryBHDPart III of BHR upgrade - Install PR2, balance, and attempt OSEM tuning

[Paco, Anchal, Tega]

After installing the short OSEMs into PR2, we moved it into ITMX Chamber. While Tega loaded some of the damping filters and other settings, we took time to balance the heavily tilted ITMX chamber. After running out of counterweigths, Anchal had to go into the cleanroom and bring the SOS stands, two of which had to be stacked near the edge of the breadoard. Finally, we connected the OSEMs following the canonical order

LL -> UR-> UL

LR -> SD

But found that UR was reading -14000 counts. So, we did a quick swap of the UR and UL sensors and verified that the OSEM itself is working, just in a different channel... So it's time to debug the electronics (probably PR2 Sat Amp?)...


PR2 Sat Amp preliminary investigation:

  • The UR channel (CH1 or CH4, on PR2 Sat Amp)  gives negative value as soon as an OSEM is connected.
  • Without anything connected, the channel reports the usual 0V output.
  • With the PDA inputs of PR2 Sat Amp shorted, we again see 0V output.
  • So it seems like when non-zero photodiode current goes, the circuit sees a reversal of gain polarity and the gain is roughly half in magnitude as the correct one.
  16629   Thu Jan 27 20:46:38 2022 KojiSummaryBHDPart III of BHR upgrade - Install PR2, balance, and attempt OSEM tuning
  • Started debugging D1002818 / S2100737 (8:30PM)
  • Confirmed the issue of the negative output of the UR sensor with the dummy OSEM connected at the air side of the ITMY chamber. Both PD Out and PD Mon have negative outputs.
  • The same issue remains when the dummy OSEM box is connected to the chassis with a short DB25M/F cable at the rack.
  • Started debugging the setup at the workbench.
    • CH1 TIA Output=-3.0V / CH2 (in question) TIA Output =-2.7V => No Problem
    • CH1 Whitening Out=+3.0V / CH2 Whitening Out=-1.4V => Problem
    • Resolder the components around whitening CH2 => no change
    • Remove AD822 and replace with a new one => CH2 Whitening OUt = +2.7V ==> Problem solved
    • PD1~3 channels of the left and right PCBs tested with the OSEM box ==> nearly +3V/-3V differential output (All Clear)
    • Chassis closing
  • Chassis restored in Rack 1Y1 and the normal output with the dummy OSEM box confirmed
  • Mission Completed (9:30PM)
  • Elog finished (9:40PM)
  • Case closed
Attachment 1: Screen_Shot_2022-01-27_at_20.33.56.png
Screen_Shot_2022-01-27_at_20.33.56.png
Attachment 2: Screen_Shot_2022-01-27_at_21.30.16.png
Screen_Shot_2022-01-27_at_21.30.16.png
  16630   Fri Jan 28 10:37:59 2022 PacoSummaryBHDPart III of BHR upgrade - PR2 OSEM finalized, reinsall LO1 OSEMs

[Paco]

Thanks to Koji's hotfix on the PR2 SatAmp box last evening, this morning I was able to finish the OSEM installation for PR2. PR2 is now fully damped. Then, I realized that with the extreme rebalancing done in ITMX chamber, LO1 needed to be reinstalled, so I proceeded to do that. I verified all the degrees of freedom remained damped.

I think all SOS are nominally damped, so we are 90% done with suspension installation!


SUSPENSION STATUS UPDATED HERE

  16631   Fri Jan 28 11:30:52 2022 KojiSummaryBHDPart III of BHR upgrade - PR2 OSEM finalized, reinsall LO1 OSEMs

All green! Great work, Team!

  16632   Fri Jan 28 16:35:18 2022 AnchalSummaryBHDAS1, PR2 and PR3 set to trigger free swing test

AS1, PR2 and PR3 are set to o go through a free swinging test at 3 am. We have used this script (Git/40m/scripts/SUS/InMatCalc/freeSwing.py) reliably in the past so we expect no issues, it has a error catching block to restore all changes at the end of the test or if something goes wrong.

To access the test, on allegra, type:

tmux a -t AS1
tmux a -t PR2
tmux a -t PR3

Then you can kill the script if required by Ctrl-C, it will restore all changes while exiting.

 

  16635   Tue Feb 1 15:33:28 2022 KojiSummaryBHDOptomechanics configuration for the in-vacuum aux small optics

I've summarized the optomechanics configuration for the in-vacuum aux small optics

It's not obvious here but the post for POP_SM4 is the stack of BA2V, Newport 9953, PLS-T238, LMR1V. The mirror is a CM254-750-E03 curved mirror. This should go on the suspension base. I hope I did not make a mistake there...

Attachment 1: Invac_opto_mechanics_v2.pdf
Invac_opto_mechanics_v2.pdf Invac_opto_mechanics_v2.pdf Invac_opto_mechanics_v2.pdf Invac_opto_mechanics_v2.pdf
  16636   Tue Feb 1 20:16:09 2022 TegaUpdateBHDPR2 candidate mirror analysis

git repo: git@git.ligo.org:tega-edo/charmirrormap.git

The analysis code takes in a set of raw images, 10 in our case,  for each mirror and calculates the zernike aberration coefficients for each image, then takes their average. This average value is used to reconstruct the mirror height map.  Finally, the residual error between the reconstructed image and the raw data is calculated.

We repeat the analysis for different field of views (FoV) namely 10mm, 20mm, 30mm, 40mm and 46.5mm and save the results in the output folder of the repo.

The analysis output for a 10mm FoV aperture at the mirror center is shown in the attachement. These three images show the input data, the reconstructed mirror surface map and the residual error.

Attachment 1: PR2_M2_data.png
PR2_M2_data.png
Attachment 2: PR2_M2_recon_FoV_10mm.png
PR2_M2_recon_FoV_10mm.png
Attachment 3: PR2_M2_residual_FoV_10mm.png
PR2_M2_residual_FoV_10mm.png
  16637   Wed Feb 2 16:22:00 2022 AnchalSummaryBHDPart III of BHR upgrade - PR2 inpute matrix diagonalized

The free swinging test was successful. I ran the input matrix diagonalization code (/opt/rtcds/caltech/c1/Git/40m/scripts/SUS/InMAtCalc/sus_diagonalization.py) on the PR2 free-swinging data collected last night. The logfile and results are stored in /opt/rtcds/caltech/c1/Git/40m/scripts/SUS/InMAtCalc/PR2 directory. Attachment 1 shows the power spectral density of the DOF basis data (POS, PIT, YAW, SIDE) before and after the diagonalization. Attachment 2 shows the fitted peaks. I chose to not type out the matrix values now. One can find them in teh repo links above.

 

Attachment 1: PR2_FreeSwingData_PeakFitting_20220125.pdf
PR2_FreeSwingData_PeakFitting_20220125.pdf
Attachment 2: PR2_SUS_InpMat_Diagnolization_20220202.pdf
PR2_SUS_InpMat_Diagnolization_20220202.pdf
  16638   Wed Feb 2 16:27:57 2022 AnchalSummaryBHDPart III of BHR upgrade - PR3 inpute matrix diagonalized

The free swinging test was successful. I ran the input matrix diagonalization code (/opt/rtcds/caltech/c1/Git/40m/scripts/SUS/InMAtCalc/sus_diagonalization.py) on the PR3 free-swinging data collected last night. The logfile and results are stored in /opt/rtcds/caltech/c1/Git/40m/scripts/SUS/InMAtCalc/PR3 directory. Attachment 1 shows the power spectral density of the DOF basis data (POS, PIT, YAW, SIDE) before and after the diagonalization. Attachment 2 shows the fitted peaks. I chose to not type out the matrix values now. One can find them in teh repo links above.

 

Attachment 1: PR3_FreeSwingData_PeakFitting_20220125.pdf
PR3_FreeSwingData_PeakFitting_20220125.pdf
Attachment 2: PR3_SUS_InpMat_Diagnolization_20220202.pdf
PR3_SUS_InpMat_Diagnolization_20220202.pdf
  16639   Wed Feb 2 16:32:02 2022 AnchalSummaryBHDPart IX of BHR upgrade - AS1 free swing test still not good

We still did not get a good AS1 free swinging spectrum. It seems the Side OSEM is reporting coupling to too many DOFs and some extra resonances than we expect. So we did not upload the new input matrix calculated from this test. I'm attaching teh peak fitting (attachment 1) and the diagonalization attempt (attachment 2) to give some idea of what happened. Note how different this fre swinging spectrum looks from the other optics. Given that Yehonathan also felt that somthing might be off with this optic, we need to reevaluate if the suspension has wire not aligned in grove, or it is imbalanced or something else if touching it still.

 

Attachment 1: AS1_FreeSwingData_PeakFitting_20220125.pdf
AS1_FreeSwingData_PeakFitting_20220125.pdf
Attachment 2: AS1_SUS_InpMat_Diagnolization_20220202.pdf
AS1_SUS_InpMat_Diagnolization_20220202.pdf
  16640   Wed Feb 2 18:55:58 2022 KojiSummaryBHDOptomechanics configuration for the in-vacuum aux small optics

Here is more detail of the POP_SM4 mount assembly.

It's a combination of BA2V + PLS-T238 + BA1V + TR-1.5 + LMR1V + Mirror: CM254-750-E03
Between BA1V and PLS-T238, we have to do a washer action to fix the post (8-32) with a 1/4-20 slot. Maybe we can use a 1" post shim from thorlabs/newport.
Otherwise, we should be able to fasten the other joints with silver-plated screws we already have/ordered.

I think TR-1.5 (and a shim) has not been given to Jordan for C&B. I'll take a look at these.

Attachment 1: Screen_Shot_2022-02-02_at_6.46.46_PM.png
Screen_Shot_2022-02-02_at_6.46.46_PM.png
  16641   Wed Feb 2 21:16:23 2022 KojiSummaryBHDOptomechanics configuration for the in-vacuum aux small optics

Asked Jordan to clean 2x 1.5" posts (0.5 dia) and a washer with 1" dia.

 

Attachment 1: PXL_20220203_050156031.jpg
PXL_20220203_050156031.jpg
  16678   Thu Feb 24 18:05:58 2022 YehonathanUpdateBHDRe-susspension of AS1

{Yehonathan, Anchal, Paco}

Yesterday, Anchal and Paco removed AS1 from the vacuum chamber and moved it into the cleanroom. The suspension wires were cut and the AS1 optic was put on the table.

Two things were noticed:

1. One of the wires was not sitting inside the side block groove (attachment 1)

2. One of the face magnets was grossly tilted (attachment 2). Probably due to uneven polishing of the dumbbell.

We put new wires into the side blocks making sure they sit in their grooves and we removed the tilted magnet. A different, more straight magnet was picked from the remaining spare magnets. The dumbbell and adapter were cleaned from glue residues and a batch of glue was prepared.

In the process of gluing a different magnet was knocked off. We cleaned that magnet too. The 2 magnets were glued on the adapter.

Today I came and saw that the gluing failed completely. One of the magnets was completely away from its socket and the other one wasn't glued at all.

I prepared a new batch of glue and glued the two magnets.

Attachment 1: signal-2022-02-24-173933_003.jpeg
signal-2022-02-24-173933_003.jpeg
Attachment 2: signal-2022-02-24-173933_002.jpeg
signal-2022-02-24-173933_002.jpeg
  16694   Wed Mar 2 14:02:43 2022 YehonathanUpdateBHDRe-susspension of AS1

Yesterday, I rebuilt the OpLev setup in the cleanroom in order to suspend AS1. It took me a while to find all the necessary parts but I found them in the end.

The HeNe laser was placed on the optical table and turned on. The beam was aimed to bounce off a folding mirror to the SOS tower.

The beam's height was controlled by the HeNe laser stage and made to be 5+14/32". The beam from the folding mirror was made parallel to the table, first with an iris and then with the QPD connected to a scope.

Preparing the SOS tower for the suspension I noticed that the wire clamp is scratched on both sides from previous suspensions. I discarded that wire clamp but couldn't find the spares. Time ran out and I had to stop.

  16698   Thu Mar 3 17:09:46 2022 PacoUpdateBHDRe-susspension of AS1

[Anchal, Paco]

Wire clamp spare was installed, furthermore AS1 was reinstalled on adapter, attached wire clamps, and cleaned using ionized air gun. Finally, we suspended it on the SOS tower and left it resting on the bottom earthquake stops; ready for balancing.

Quote:

Yesterday, I rebuilt the OpLev setup in the cleanroom in order to suspend AS1. It took me a while to find all the necessary parts but I found them in the end.

The HeNe laser was placed on the optical table and turned on. The beam was aimed to bounce off a folding mirror to the SOS tower.

The beam's height was controlled by the HeNe laser stage and made to be 5+14/32". The beam from the folding mirror was made parallel to the table, first with an iris and then with the QPD connected to a scope.

Preparing the SOS tower for the suspension I noticed that the wire clamp is scratched on both sides from previous suspensions. I discarded that wire clamp but couldn't find the spares. Time ran out and I had to stop.

 

  16710   Mon Mar 7 16:56:08 2022 YehonathanUpdateBHDRe-susspension of AS1

{Paco, Yehonathan}

We tried to roughly balance the adapter with two counterweights at the front, like with the other thin optics using an iris. As before, we couldn't get the beam above the iris hole no matter how much we inserted the counterweights into the adapter. We noticed that one of the side blocks is actually the one where the clearance for the wire was made on the wrong side. So there was clearance on both the up and bottom sides of the side block (see attachment 1).

Could this be the cause of the balancing issue? Running out of ideas on how to fix it we gave it a try and replaced it with a spare side block. We also found that the wire on the other side block was kinked so we replaced the wire on this one as well.

After inserting new wires into the side blocks, we hung the adapter on the winches and the beam was above the iris aperture! How could this tiny amount of missing mass make this much difference?

We were able to roughly balance the adapter.

We then tried to balance the roll of the adapter but accidentally knocked off the side magnet 😫.

We usually glue several side magnets together and they all together support the metallic plate on which the magnets are magnetically attached to. This time we had only one side magnet to glue so instead of trying to glue the magnet vertically we are trying to glue it horizontally using a flat surface and a stage to clamp it (attachments 2,3).

BTW, the HeNe was not working when we came into the cleanroom. We realized it was the old HeNe that we already determined to be broken but there was no sign on it. I attached a "BAD" sign on it and replaced it with the new HeNe. The OpLeve beam was realigned. All of this happened before all the things described above

Attachment 1: signal-2022-03-07-171520_001.png
signal-2022-03-07-171520_001.png
Attachment 2: signal-2022-03-07-172659_001.jpeg
signal-2022-03-07-172659_001.jpeg
Attachment 3: signal-2022-03-07-172659_003.jpeg
signal-2022-03-07-172659_003.jpeg
  16711   Mon Mar 7 18:53:16 2022 KojiUpdateBHDRe-susspension of AS1

Not sure if that small difference can cause the alignment inability. Particularly, the removed metal was just below the wire. This means that there is no misalignment effect at the first order.

Here is my idea:
You may be able to assist the alignment by adding washers on one side of the four holes to this "H" shaped parts. The holes are away from the center line, adding some weight definitely do some misalignment.

 

  16714   Tue Mar 8 12:24:13 2022 YehonathanUpdateBHDRe-susspension of AS1

The gluing seemed to be successful. I assembled the side block with the magnet on the adapter. Paco helped me hang the adapter on the SOS tower.

The height and roll of the adapters were balanced (attachment 1,2).

The QPD was placed at the beam reflection. The beam was centered horizontally on the QPD and then measured vertically. The pitch DOF was balanced using the counterweights. The counterweight was locked. Balance was retained.

I tried to assemble the upper mirror clamp on the tower but for some reason, one of its tap holes was not able to accept screws. I gave it to Jordan for retapping. I measured the motion spectrum using the QPD connected to a scope (attachment 3).

Major peaks are at 668mHz, 942mHz, and 1029mHz.

 

Attachment 1: AS1_Roll_Balance.png
AS1_Roll_Balance.png
Attachment 2: AS1_Height_Balance.png
AS1_Height_Balance.png
Attachment 3: FreeSwingingSpectra_new.pdf
FreeSwingingSpectra_new.pdf
  16715   Tue Mar 8 19:29:36 2022 PacoUpdateBHDRe-balance of AS1

[Paco]

Installed AS1 in vacuum, near the center of the table, and installed the OSEMs. All OSEMS are "balanced" nominally, i.e. their shadow is at the halfway point optimum, but fine tuning is required, which I will attempt tomorrow after restoring the AS1 suspension screen settings. Today, I tried damping the SIDE DOF, but didn't succeed, although there was definitely some oscillating behaviour with high (> 5) gains on the damping, so I believe this is a matter of patience. For now, all OSEMs are looking ok, the SOS is in place, and hopefully it will soon be damped. 

  16716   Wed Mar 9 09:35:26 2022 PacoUpdateBHDRe-balance of AS1

[Paco]

AS1 is installed, OSEMs balanced, and the optic damped successfully. We should run the free swinging test overnight to validate this re-installation.

  16718   Wed Mar 9 11:52:18 2022 YehonathanUpdateBHDSimplified BHD readout sketch on ITMY table

I have made an editable draw.io diagram of the planned simplified BHD setup on the ITMY table (see attached).  10 pts = 1 inch.

This is very sketchy but easily adjustable since we are removing everything but the ITMY Oplev from that table.

Attachment 1: ITMY_Table_Sketch.drawio.pdf
ITMY_Table_Sketch.drawio.pdf
  16719   Wed Mar 9 12:57:52 2022 KojiUpdateBHDSimplified BHD readout sketch on ITMY table

- BHD beams were already mixed in the chamber. So we don't need a BS on the table. (Probably there is no BS already)

- We don't need to split each BHD beam. One PD per BHD beam is OK for now.

- Check if the BHD paths have reasonable angles from the windows so that the beams do not hit the chamber wall.

- We need the POY path. POY indeed goes to the BS table

  16729   Tue Mar 15 18:42:37 2022 AnchalSummaryBHDPart IX of BHR upgrade - AS1 resuspended and OSEMs tuned

http://nodus.ligo.caltech.edu:8080/40m/16722

http://nodus.ligo.caltech.edu:8080/40m/16716

  16730   Tue Mar 15 18:45:12 2022 AnchalSummaryBHDPart X of BHR upgrade - BHDBS Path setup

[Paco, Anchal]

BS Chamber work

  • ASL was positioned in nominal place.
  • PR3 was moved to its nominal place from temprorary position.
  • BS Table was rebalanced
  • Earthquake stops were removed from all SOS from BS table (LO2, SR2, BS, PR3)

ITMY Chamber work

  • AS2, AS3, LO3, LO4, and BHDBS were positioned in the nominal place.
  • AS1 was moved to its nominal place from temporary position.
  • ITMY tbale was rebalanced
  • Earthquake stops were removed from all SOS from ITMY table (AS1, AS4, ITMY)
  16732   Thu Mar 17 16:50:53 2022 PacoUpdateBHDXARM AUX alignment

[Ian, Paco]

We opened the ITMX chamber and

  • Inspected PR2 and LO1 and didn't see anything suspicious.
  • Took the EQ stops off ITMX in preparation for alignment

Alignment:

  • Ian started at the ETMX station, slightly tweaking the M1 M2 XAUX mirrors by hand and Paco on the ITMX chamber looking at the beam. The beam was visibly making it to the ITMX optic and reflecting back though at a negative pitch angle. No small motion on the M1-M2 knobs caused visible correction on this.
  • We decided to try adding an alignment offset to ITMX, and quickly saturated to 25000 (on the SUS screen) but fell short of fully correcting this PIT offset.
  • We scanned further the M1 M2 input alignment, and briefly lost the first reflection.
    • We recovered the first reflection, but the beam spot is now incident near the LL OSEM position.
  • We kept scanning M1 - M2 with Ian on the ITMX chamber this time, providing feedback through facetime.
  • Leaning on the ITMX chamber table, we noticed the magnitude of PIT correction left to be done and verified that M1-M2 two axis alignment + ITMX offsets should be enough for it.

We stopped our effort here, the XAUX beam spot is near the lower half of the ITMX face. Tomorrow, we will resume, but we will use airpods and a clean go-pro for real-time audiovisual feedback. Furthermore, ITMX OSEMs should be rebalanced as they haven't been touched after the table was balanced for PR2 and LO1.

  16733   Thu Mar 17 17:23:22 2022 AnchalSummaryBHDPart IIa of BHR upgrade - Green laser alignment

[Anchal, Yehonathan] (on Y Arm)

We first checked if the PZT mirrors M1 and M2 can be controlled. They indeed show no motion even after being connected with a power supply. So green injection path can not be aligned using cds controls right now.

We also noticed that all ETMY slow controls and monitors are offline. That's because the electronics upgrade did not include acromag chassis. This means that the DC bias adjustment is not accessible for ETMY.

Alignment work:

  • We first aligned the green injection beam to cross two irises in the injection path to ETMY chamber.
  • Then I (Anchal) went inside the ITMY chamber to find the green light. Yehonathan controlled the injection path while I gave feedback from ITMY side. We aligned injection path to get the beam near center of ITMY.
  • Then I aligned ITMY through sitemap>IFO>Align to get counter propagating reflection near the ITMY side.
  • We were able to see reflection from ETMY hitting the beam tube.
  • Since DC alignment controls of ETMY are not accessible, we used the Alignment offset in rtcds model which puts dc offset in the coil driver to get the reflected beam from ETMY to come to ITMY table, about 1 inch above the table and about 3 inch south of ITMY SOS.
  • But we got limitted by the DAC overflow on ETMY at this point. Several back and forth attempts to relief ETMY were unsuccesful.

Possible issues:

  • We think having the HV coil driver set up for ETMY is important for this alignment work if not essential. The coil drivers of ETMY are near saturation.
  • We also think that addition of two new suspensions in ITMY table and then counter weights to balance the table, has depressed table height slightly. We need to work out how to change injection path height and angle accordingly.

[Paco, Ian] (on X Arm)

http://nodus.ligo.caltech.edu:8080/40m/16732

  16735   Fri Mar 18 17:15:19 2022 PacoUpdateBHDXARM AUX alignment cont.

[Paco, Ian]

First, we re-balanced the ITMX OSEMs so that they would damp at around half-a-shadow.


Then, we set up a clean camera inside ITMX chamber looking at the ITMX optic. Then, using the live feed we aligned the AUX beam from the ETMX station using M1 and M2. The camera was great to help us align the beam properly close to the ITMX center. It wasn't very long until we could see a green beam on the IR card, but we didn't really see any flashing, so this may just be the bare transmission away from XARM resonance (Attachment #1).

Ian checked the reflection from ITMX using the IR card with holes, and he pretty much only saw one beam spot, so we turned to look for a beam scattering on the vacuum tube but didn't really see anything. This could mean that we were hitting the ETMX again, or missing slightly, or missing completely. We tried scanning the ITMX pitch and yaw using the bias (alignment) sliders, and with the illuminators off, try seeing some scattered green beam on the ETMX. We can't really see anything yet, but we will keep trying. If there are any tips on our method, it would be great to know them.

Attachment 1: Screen_Shot_2022-03-18_at_4.09.38_PM.png
Screen_Shot_2022-03-18_at_4.09.38_PM.png
  16739   Mon Mar 21 18:00:05 2022 Ian MacMillanUpdateBHDXARM AUX alignment cont.

[Ian, Paco]

Continuing with the previous alignment that we stoped on friday, we re set up my heavily cleaned iPhone on FaceTime. The Phone alowed us to see the laser on the ITMX and center it on that optic.

  • We increased the trigger level for the watchdog on the optics.
  • Green beam was centered on th ITMX.
  • aligned the green laser: prompt reflection off of the ETMX to maximize the signal on the reflection PD
  • Went back to ITMX chamber, looked for the beam in the tube to see if the laser was hitting the beam tube off of the ITMX. From there we comunicated how to adjust the beam to move the beam towards the ETMX.
  • On the ETMX the reflection PD signal was measured and the ITMX was adjusted using CDS until ripples/"flashes" were seen in the reflection PD channel (C1:ALS-X_REFL_DC_OUT_DQ).
  • Once we saw flashing we tried to minimize the reflection pd signal using only ITMX alignment slider so that all the light was being held in the cavity.
  • Once we had this going the PDH lock engaged the higher order mode that we were seeing.
  • We removed the phone setup and closed up the ITMX chamber.
  • From here we moved to the control room and continude to adjust the ITMX and ETMX to see if we could lock to a lower order mode.
    • This proved unsuccessful so we will resume by trying to replicate the ASS action manually (with M1 - M2 PZT sliders and the REFL PD)
Attachment 1: PXL_20220322_015247138.jpg
PXL_20220322_015247138.jpg
  16740   Mon Mar 21 18:24:07 2022 AnchalSummaryBHDPart IIa of BHR upgrade - Green laser alignment on Yarm

[Anchal, Tega]

We did the following alignment steps on Yarm today:

  • We aligned the green beam going into the ETMY chamber to the three irises on the path.
  • We aligned ETMY to get counter-propagating prompt reflection from ETMY.
  • We were able to see light in the reflection photodiode for the green PDH loop.
  • Then we went to ITMY chamber and checked where the beam is coming to. It was coming very low in height.
  • We walked the beam on the end to get it near the center of ITMY.
  • Then we changed the ETMY alignment again to get back the reflection beam on the reflection photodiode.
  • Then we went again to ITMY chamber and changed the ITMY alignment to get counter-propagating reflection from ITMY.

After this, we came back to the control room. One peculiar thing to note is that the C1:LS-Y_REFL_DC_OUT channel is inverted i.e. it is showing negative values for the reflection DC voltage. On this signal, we see a little bit higher-order mode flashing but it is not bright enough to be seen on the face camera of the suspension. We'll continue aligning the cavity using CDS now to get TEM00 mode.


After trying for a bit, we were able to get flash of about 2000 counts which is about 16% of the max value of 12200 counts. We adjusted the ITMY angular position using the IFO_ALIGN screen but used the OPTICAL_ALIGN offset screen to adjust the angular position of ETMY. The pitch and yaw values for ITMY are 1.0360 and -0.260 respectively whereas the pitch and yaw values for ETMY are 5664.0 and -4937.0 respectively. 

  16742   Thu Mar 24 19:20:28 2022 AnchalSummaryBHDPart IIa of BHR upgrade - Green laser alignment on Yarm

[Anchal, Paco]


Uneloged: yesterday, Paco and Ian tried locking the green laser on Yend to the Y-arm. Nothing noteworthy happened, no luck.


  • Started with aligning the green injection to the Iris on table (it was misaligned) and getting it on the ITMY center.
  • Then we realized that the beam is going through the focusing leans very offceter. This makes the beam warped and deflected inside that needs to be corrected by mirrors.
  • So we decided to adjust the lens position first.
  • We realized that lens position is hard to adjust along with keeping the beam hiting ITMY.
  • So, we decided to remove the lens first and just align the green beam directly with the Iris on the table and the ITMY center. The beam became as big as ITMY when it reached there without the lens in path. We aligned it to fall on the mirror.
  • Then we placed the lens back so that the beam goes through the center of the lens.
  • Then we aligned ETMY to get the reflection back to the reflection PD.
  • But then when we checked the beam at ITMY again, it was severely missing ITMY. The possible reason is that ETMY is a diverging lens for the beam as well and changing its position changed the beam direction in the beam tube.
  • We decided to do another iteration of lens positioning with the new ETMY position. So same steps, removed lens, aligned beam with iris and ITMY, placed back the lens, aligned ETMY again to get reflection back on the PD.
  • This time the beam was still reaching ITMY. So we were glad that our iterations converged in 2 repititions.
  • Then we aligned ITMY to get counter propagating beam.
  • At the end of this alignment:
    • We see dips in relfection photodiode counts from 12200 to 9500.
    • The ETMY oplev is partially out of range (only 1 of the quadrant seeing light) but that could be because we changed the lens position. So Oplev servo is off.
  • We confirmed that the PDH servo is properly connected and loop is on. But we see no HOM catching lock for YARM even after us doing about 10 min search with ITMY-ETMY alignments.
  • We are leaving things as it is. We'll continue trying to align the cavity tomorrow. Everyone is welcome to try as long as they restore the positions of the optics to a good state at the end.

 

 

  16744   Fri Mar 25 18:20:28 2022 AnchalSummaryBHDPart IIa of BHR upgrade - Green laser alignment on Yarm

[Anchal, Paco, Shruti]

  • Today we found out that the laser controller at the Yend had it's inputs disconnected for the FAST PZT input and the Slow temperature control input. The cables were also not labeled that were lying nearby.
  • I tracked the cables and connected the Fast input adn the slow input.
  • We then adjusted the temperature slider to go to previously marked laser crystal temperature of 40.1 degrees celsius. But we could not find the the beatnote of Y end IR with teh Main laser IR.
  • We scanned the laser crystal temeprature until we could see a beatntoe with the main IR laser and stopped in that region.
  • Then we continued looking for flashing and HOM, but no luck.
  • It was interesting that when the PDH loop was closed, we saw fluctuations in relfection photodiode DC value, but not so much when the loop was not closed.
  • We tried flipping the sign of the loop with no luck and we tried changing the gain of the loop as well, but no luck.
  • The behavior of this Yend laser and its controller is still suspicious to us. When the loop is closed, the PZT feedback signal should not cause a change in amplitude of the light so much as we see it.
  • Also the fact that when loop is clsoed we do not see signs of flashing in the reflection photodiode is interesting. If anyone has any ideas, that would be good.
  16745   Sat Mar 26 13:04:38 2022 PacoSummaryBHDPart IIa of BHR upgrade - Green laser alignment on Yarm

I came for a bit to check on the "1Y0 burning smell" reported by Koji last evening. I agree that there's a toasty smell around the 1Y0 rack, but it is hard to tell where it comes from exactly. I think we can use the FLIR heat camera, but this will have to wait for Monday when someone with an iphone is around.

I also played a bit with the YAUX alignment (which is still poor) but I didn't try anything different nor did I seem to have more success. This is also an outstanding item for Monday, where maybe the next step is to install the GTRY path for a CCD.

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