40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
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  21   Thu Oct 13 16:06:34 2016 StephenSummaryPMC WorkTesting of Spring Plate for PMC Spacer Assy

Abstract

The purpose of this test was to evaluate a spring plate in a custom optic mount design which will be deployed in the reworked and upgraded PMC Spacer Assy per D1600270.

Summary of Results (Fit)

Mechanical inspection of the fabricated showed conformance to manufacturing specifications. Assembly of the Fit Test Interface Assy D1600398 in the nominal configuration was successful.

  • The primary source of assembly clearance was the 0.030” radial gap between the mirror and the 1in. Mirror MT.
  • Secondarily, assembly clearance was evident in the clearance bore bolt circle in the 1in. Mirror MT. for the M2.5 x 0.45 SHCS.

Some additional consideration (Tooling? Interfacing part?) may be necessary to combat these sources of “slop” and permit repeatable assembly.

Summary of Results (Holding Force)

The Fit Test Interface Assy D1600398 was laid flat on the work bench with the normal axis of the mirror vertical. The force required to overcome the static friction for a given spring plate defection and induce macroscopic translation was evaluated as follows:

  • 0.050” deflection (nominal): 6 +/- 0.5 ounces of force (1.7 newtons)
  • 0.030” deflection: 4 +/- 0.5 ounces of force (1.1 newtons)
  • No spring plate: no measurement, as this force was too small for this experimental set-up

In comparison, the weight of the optic is estimated to contribute a force of 1.6E-2 newtons in the nominal orientation. The optic did not sag in the mount when held in the nominal configuration and orientation for 2 hours.

In shipping configuration, the set screws were found to couple rigidly to the barrel of the optic and provide sufficient static friction to withstand jarring motions. The design seems to be sound from a shipping point of view.

Summary of Results (Comparison with COTS)

Two Commercial Off-The-Shelf (COTS) optic mounts were investigated. Barrel contact points, namely two flats and a preloading point-contact plunger, were used in conjunction with a spring plate. The assembly was rigidly coupled with high static friction constraining all degrees of freedom.

Perhaps barrel contact points should be employed in the LIGO design.

 

-----------------------------------------------

Full Description of Experiment

-----------------------------------------------

 

COTS Spring Plate Mounts

Two models of Commercial Off-The-Shelf (COTS) Low Outgassing optic mounts from Newport which provide axial clamping using the COTS 906919-02 Mirror Mount Spring Plate were investigated. Both use the Spring Plate in conjunction with barrel contact points, namely two flats and a preloading point-contact plunger.

An optic is loaded into these mounts by using the barrel to depress the plunger, then tilting the optic into flush face contact with a retaining lip that is integral to the mount. The plunger then pushes the optic into its seat on the two flats (visible contacting the right hand site in the image below). Subsequently, the blade spring is bolted to the exposed face, and the assembly is rigidly coupled with high static friction constraining all degrees of freedom.

Optic Mount models are:

  • NewFocus (Newport) 902817-04 (9817-6-NI-K) (pictured below, with dirty optic)
  • NewFocus (Newport) 902816-04 (9814-6-NI-K)

 

Inspection

The parts procured for the Fit Test Interface Assy D1600398-v1 were received in good condition. Using micrometers, calipers, and pin gages, Stephen employed partial inspection of mating and critical features to establish that the parts were made to specification by the vendor. The parts consisted of the COTS 906919-02 Mirror Mount Spring Plate (Qty 25, New Focus / Newport), the D1600233-v1 1in. Mirror MT. (Qty 1, ProtoLabs), the D1600397-v1 Base Plate (Qty 1, ProtoLabs) and assorted COTS hardware and fasteners.

The only item worth raising from this inspection is the difficulty of inspecting the 1.010” Diameter pocket in the D1600397-v1 base plate. No accurate measurement could be made due to the nominal .030” high shoulder, the nominal .0075” machine tool radius, and the un-deburred lip, all of which limited the contact area and precision for the calipers. A fit check of the PZT showed that the pocket was large enough to insert the PZT, and this was taken to be sufficient to “Pass” the size dimension on this feature.

Assembly

To assemble the Fit Test Interface Assy, the following procedure was followed:

  1. The COTS 906919-02 Mirror Mount Spring Plate was bolted to the D1600233-v1 1in. Mirror MT. and the subassembly was placed flat on the workbench with the spring plate on the table side.
  2. The 25 mm Diameter x 5 mm Thick mirror was laid flat on top of the spring plate within the 1in. Mirror Mount, with the HR-coated side facing away from the table. Now, the AR-coated side was in contact with the Spring Plate.
  3. The M2 x 0.4 set screws were tightened onto the barrel of the mirror until rigidly coupled, with the mirror centered by eye in the 1in. Mirror Mount. THIS WAS NOT A VERY PRECISE CENTERING OPERATION, but using a pin gage as a spacer, I was able to position the optic within 0.005” of the center of the mount.
  4. The 1in. Mirror Mount was lowered toward the surface of the D1600397-v1 Base Plate, until the HR-coated side was registering on a single plane with three locations of point contact.

  1.  The M2.5 x 0.45 SHCS were tightened by a couple of turns, indexing the 1in. Mirror Mount BUT NOT LOADING THE SCREWS. The 1in. Mirror Mount was NOT in contact with the Base Plate. THE SLOP IN THE CLEARANCE BORES DID NOT PERMIT PRECISE CENTERING AT THIS STAGE.
  2. The set screws were loosened and retracted into the threaded bores to prevent any possible contact with the barrel of the mirror.
  3. The 1in. Mirror Mount was bolted to the Base plate using the M2.5 x 0.45 SHCS with tightening conducted in stages, so that each tab was loaded approximately 1 mm at a time. A final torque of 5 in*lb was applied, per T1100066 (interpolation between #2-56 and #4-40).

Note that the mirror used in this experiment was a flat mirror removed from PMC 10. See item 36 of D1001955-v2 Assembly Drawing.

Evaluation

Using the Fit Test Interface Assy D1600398 and a 36 ounce Jonard Compression/Tension Force Guage, the holding force of the 906919-02 Mirror Mount Spring Plate was tested.

This holding force was found to hold the optic tightly without macroscopic translation in the nominal mount configuration (0.050” axial deflection on spring plate) until acted upon by approximately 6 ounces of force (converted, about 1.7 newtons). This force was applied approximately perpendicular to points on the barrel of the mirror near the face opposite the 3-point contact plane.

SEE 50thou Holding Force.MOV

In contrast to the nominal 0.050” of deflection on the spring plate, under an axial deflection of 0.030” approximately 4 ounces of force (1.1 newtons) were required to overcome the static friction and induce macroscopic translation. This set-up utilized precise shims to reduce the deflection, as shown below.

SEE 30thou Holding Force.MOV

The force required to induce macroscopic translation without the spring plate installed was too small to be measured with the same set-up.

SEE NoSpring Holding Force.MOV

The weight of the optic contributes a force of 1.6E-2 newtons in the nominal orientation, using a calculated volume of 0.78 cm^3 and an estimate density of 2.2 grams per cm^3. The optic was set in the Interface Assy for 2 hours under the nominal configuration, and no gravitational sag was observed (using a pin gage as a probe).

 

Evaluation of Shipping Configuration

In order to push the limits of the holding force of the mount for shipping purposes, the mount was carefully subjected to a repeated jarring motion (held with one hand and "clapped" firmly into the other) with the set screws driven tightly into the barrels. The contact provided by the set screws and the spring plate in conjunction was sufficient that the optic did not macroscopically move (using a pin gage as a probe). Meanwhile, when the optic was held only by the spring plate and the mount was subjected to the same jarring motion, the optic did macroscopically move. The set screw contact on the barrel is very much necessary for shipping of the optic in place within this mount in order to provide sufficient static friction to rigidly couple the optic to the mount.

 

 

 

Attachment 1: image3.JPG
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Attachment 2: image2.JPG
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Attachment 3: image1.JPG
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Attachment 4: image1.JPG
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Attachment 5: image5.JPG
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Attachment 6: image11.JPG
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Attachment 7: 30thou_Holding_Force.MOV
Attachment 8: 50thou_Holding_Force.MOV
Attachment 9: NoSpring_Holding_Force.MOV
Attachment 10: image21.JPG
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Attachment 12: image22.JPG
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  170   Wed Jul 24 10:13:38 2019 Marie K. SummaryBS BRDsSummary of tests with BRDs v4

I haven't posted the BS transfer functions results since we started to test the BS with 2 BRDs attached. I can now read the data that has been saved in .78D from the spectrum analyzer, which makes data analysis much easier! (see elog 171).

  • The first set of tests (tests srs0014.txt to srs0018.txt) were done with BRD1_v4 and BRD2_v4 on the beam splitter.
  • Then, I noticed the blade of BRD2_v4 had been torqued to much. BRD2_v4 was replaced by BRD3_v4. The tests are srs0019.txt to srs0021.txt.
  • Finally I removed both BRDs from the BS to remeasure their tuning. I took this opportunity to remeasure BS modes undamped because I didn't have global scans saved in the .78D format. I'm still missing precise scans for the bounce mode (also because not saved in .78D format originally).

The results are summarized in the tables below and in the figures attached.

Bounce

B1 Freq. [Hz]

Q1 (from 3dB width) B2 Freq. [Hz] Q2 (from 3dB width) BRD tuning Measured range  Nb points Drive [V] Filename Comments
Measurement B6 16.733 325 - -   16 - 17 600 1 srs0015.txt BRD1_v4 + BRD2_v4 on
Measurement B7 16.742 46 - - BRD3 tuned 16.3 - 17.2 600 1 srs0020.txt BRD1_v4 + BRD3_v4 on
Measurement B8 16.749 289 - - drift from B7? 16 - 17 600 1 srs0021.txt BRD1_v4 + BRD3_v4 on

Is the low Q of measurement B7 due to a very good tuning? See elog 164, BRD3 was tuned to 0.01%. The measurement B7 was taken soon after tuning, and the BRDs might have drifted for the folllowing measurement B8. However, we don't see this good performance in the overall scan that was taken just after installing BRD3 on BS (see figure 3).

To do: retake transfer functions of the bounce mode region with and without the dampers to confirm the Qs. Understand the difference in the measurements (drifts?). A tentative summary is presented in figure 1, but the undamped mode is missing from the figure.

 

The results are so far are cleaner for the roll mode (see figure 2).

Roll

R1 Freq. [Hz]

Q1 (from 3dB width) R2 Freq. [Hz] Q2 (from 3dB width) BRD tuning Measured range  Nb points Drive [V] Filename Comments
Measurement R11 24.116 182 24.419 161   24 - 24.6 600 0.1 srs0016.txt BRD1_v4 + BRD2_v4 on
Measurement R12 24.110 174 24.414 167   24 - 25 600 0.1 srs0018.txt BRD1_v4 + BRD2_v4 on

We can see that adding a second BRD helped to reduce the Q of the second resonance from ~250 to ~170. From elog , we know that the undamped Q of BS is around 3000, and that adding the first BRD split the resonance in two, with Q1 below 200 and Q2 around 250. A third resonance/feature can be seen on the glocal scans, but it is outside the frequncy range of our current measurements.

To do: Take measurements over a larger range (on the high frequency side) to check the third resonance. Add a comparison with the model to check if the measured behavior is expected.

 

Attachment 1: BS_bounce_BRD_July2019.png
BS_bounce_BRD_July2019.png
Attachment 2: BS_roll_BRD_July2019.png
BS_roll_BRD_July2019.png
Attachment 3: BS_summary_July2019.png
BS_summary_July2019.png
  181   Sun Aug 4 16:36:07 2019 Marie K.SummaryBS BRDsSummary of BS measurements after retuning

Andy retuned BRD1_v4 and BRD3_v4 after they had been left alone for a week in the lab. The tuning is described here: alog 177. It is better than 0.4% for all modes of the BRDs. I reinstalled them on BS right afterwards and took measurements of the bounce and roll modes over the following days:

We can see (figure 1) that the resonances are drifting. The BS bounce mode is 16.69 Hz without BRDs, so it is probably B2 here with the added mass.

Bounce

B1 Freq. [Hz]

Q1 (from 3dB width) B2 Freq. [Hz] Q2 (from 3dB width) BRD tuning Measured range  Nb points Drive [V] Filename Comments
Measurement B12 16.550 108 16.747 172 - 16 - 17 600 1 srs0034.txt BRD1_v4 & BRD3_v4
Measurement B13 16.555 153 16.761 232 - 16 - 17 600 1 srs0041.txt BRD1_v4 & BRD3_v4
Measurement B14 16.560 139 16.754 227 - 16.4 - 17 600 1 srs0042.txt BRD1_v4 & BRD3_v4

 

The roll mode also experiences drifts, but to a lesser extent. The BS roll mode is 24.34 Hz without the BRDs. It is probably R2 here with the added mass.

Roll

R1 Freq. [Hz]

Q1 (from 3dB width) R2 Freq. [Hz] Q2 (from 3dB width) BRD tuning Measured range  Nb points Drive [V] Filename Comments
Measurement R13 24.034 126 24.507 160 - 24 - 25 600 1 srs0033.txt BRD1_v4 & BRD3_v4
Measurement R14 24.049 138 24.526 187 - 23.5 - 25.5 500 1 srs0039.txt BRD1_v4 & BRD3_v4
Measurement R15 24.051 139 24.528 195 - 23.5 - 25.5 600 1 srs0040.txt BRD1_v4 & BRD3_v4

 

Unfortunately, some of the measurements are not readable. I will retry the conversion from .78D to .txt. Files I have to mention that saving the data from the spectrum analyzer is unreliable at times, I already lost few hours of measurements because the files were not saved correctly into .78D in the first place (.78D files were empty).

Attachment 1: B12_B14.png
B12_B14.png
Attachment 2: R13_R15.png
R13_R15.png
  192   Mon Aug 19 12:10:01 2019 Agueda B.SummaryIR cameraRemeasuring the Beam Size and Finding the Second Point Absorber

[Marie, Andy, Agueda]

Using a beam analyzer, we found that the laser beam had a mean width (diameter) of 5438.17 micro meters. Below are the images produced by the beam analyzer. 

We then proceeded to record the second point absorber on the test mass with the IR camera. Although we increased the beam's percent power every minute, with the maximum being at 95%, the laser did not show up on the recording.

Attachment 1: meas1_20190819.png
meas1_20190819.png
Attachment 2: meas2_20190819.png
meas2_20190819.png
Attachment 3: meas3_20190819.png
meas3_20190819.png
  195   Mon Aug 19 14:34:08 2019 Agueda B.SummaryIR cameraMillimeter/Pixel Calculations for the Point Absorbers

Below are my calculations to find the millimeter/pixel (mm/pxl) within two images taken by the IR camera: one of the first point absorber and one of the second point absorber that were previously on the test mass. Attached are the pictures used to find the mm/pxl results. 

 

PT Absorber 1 

*The pythagorean theorem was used only for the first point absorber's calculations, as the pixel ruler on Preview would not work because the mark is angled. Changing the angle of the picture would change the picture size, thus producing an inaccurate mm/pxl result*

(Marker as a Whole)

- 9.5 mm/ 251 pxls wide = 0.04 mm/pxl

- 6.0 mm/ 153 pxls tall =  0.04 mm/pxl

(Inner Circle of Marker)

- 2.5 mm/ 73 pxls wide =  0.03 mm/pxl

- 1.9 mm/ 51 pxls tall =  0.03 mm/pxl

(Marker Outline)

- 3.0 mm/  93 pxls thick (left) =  0.03 mm/pxl

- 3.1 mm / 97 pxls thick (right) =  0.03 mm/pxl

- 1.9 mm/  52 pxls thick (top) =  0.04 mm/pxl

- 1.5 mm/  45 pxls thick (bottom) =  0.03 mm/pxl

 

PT Absorber 2

(Marker as a Whole)

- 4.5 mm/ 136 pxls wide =  0.03mm/pxl

- 5.8 mm/ 170 pxls tall =  0.03 mm/pxl

(Inner Circle of Marker)

- 1.5 mm/ 55 pxls wide =  0.03 mm/pxl

- 2.0 mm/ 62 pxls tall =  0.03 mm/pxl

(Marker Outline)

- 1.6 mm/ 52 pxls thick (left) =  0.03 mm/pxl

- 1.0 mm/ 45 pxls (right) = 0.22 mm/pxl

- 1.9 mm/  60 pxls (bottom) = 0.03 mm/pxl

- 1.5mm/ 58 pxls (top) =  0.03 mm/pxl

Attachment 1: First_Point_Absorber_(August_6).tiff
Attachment 2: Second_Point_Absorber_(August_6).tiff
  214   Thu Oct 31 16:54:45 2019 Marie K.SummaryBS BRDsSummary of the BRDs results with version 4 of the blades

BRDs with the version 4 of the blades have been tested on stand-alone version and in the BS suspension during the summer. Here is a summary of our findings with the references to the corresponding elogs.

Stand alone:

Drifts measured on two BRDs before baking over 20 and 40 days (elog 186). The variation of the resonance frequencies are reported in the table below:

 

BRD1

BRD2

BRD4

 

Bounce

Roll

Bounce

Roll

Bounce

Roll

Time lapse dt [days]

19

41

5

Drift df [Hz]

0.145

0.417

0.218

0.184

0.160

0.196

Drift df [%]

0.87

1.71

0.76

1.31

0.94

0.81

Drift Rate [mHz/day]

7.63

21.96

5.32

4.49

32.00

39.20

Drift Rate [%/day]

0.09

0.04

0.03

0.02

0.18

0.16

  •  The BRD2 modes seem to stabilize after a month of steady increase (see figure 1). The rate of frequency drift is about few hundreds of ppm a day.  The drift rate of BRD1 is of the same order but the measurements were stopped before it stabilized.
  • After baking (elog 197), the BRD4 is measured over 5 days. The rate of the frequency drift dramatically increases (by a factor 4). It might be partly due to the fact that the BRD was mounted after being backed and there is a relaxation in the mount.
  • The value of the Qs is around 150 (elog 177)
  • Reference for all the measurements can be found at: T1900569

On the dummy BS suspension:

1 - Resonance frequencies

The two BRDs were installed on the dummy BS for a month. Unfortunately we are missing some of the measurements because some data got corrupted (see spreadsheet attached). Therefore the analysis is only performed over 16 days (8 days) for the bounce (roll) mode.

For each mode (bounce and roll), two peaks are observed around the resonance where we expected to resolve three peaks. The three peaks would be the main BS resonance as well as one peak per BRD. We might need to increase the scan resolution (see figure 2 and 3).
The frequency of the peaks do not match the frequency of the BRDs measured alone. The frequency of the minima in between the resonance peaks is close to the resonance frequency of the BS for respectively the bounce and the roll modes. The shift in the BS resonance frequency due to the added mass is negligible.

We observed a steady drift of the resonance frequencies over time. The frequencies are increasing by few hundreds of ppm per day, see below and figures 4 and 5.

Summary of BS Bounce frequencies

Time lapse dt [days]

16.00

16.00

Initial mistuning [%]

0.84

-0.34

Final mistuning [%]

0.64

-0.61

Drift df [Hz]

0.034

0.044

Drift df [%]

0.21

0.26

Drift Rate [mHz/day]

2.125

2.75

Drift Rate [%/day]

0.01

0.02

We are observing a change of 0.2% in the resonance frequency over the 16 days. This is above the requirements that we set at 0.1% tuning. We didn’t observe a stabilization in the drift.

Summary of BS Roll frequencies

Time lapse dt [days]

8.00

8.00

Initial mistuning [%]

1.26

-0.69

Final mistuning [%]

1.12

-0.87

Drift df [Hz]

0.034

0.045

Drift df [%]

0.14

0.18

Drift Rate [mHz/day]

4.25

5.625

Drift Rate [%/day]

0.02

0.02

We are observing a change of 0.1% in the resonance frequency over the 8 days. We didn’t observe a stabilization in the drift, so this is likely to exceed our requirements.

When remeasured stand-alone after being uninstalled from the BS suspension, we established that the BRDs frequencies drifted of about 0.5% after being for a month on the suspension (elog 203).

2 - Q factor

The resonance amplitudes, corresponding to the quality factor of the modes, fluctuate over time without a distinguishable pattern. However, it seems that for each mode the two resonances vary together, in particular for the roll modes.

The mean of the bounce mode Q is 140 (168) for the 16.66 Hz (16.69 Hz) resonance. The mean of the bounce mode Q is 115 (152) for the 24 Hz (24.5 Hz) resonance. Q are lower than expected according to the model (we expected Q~200).

Conclusion:

We observed a steady drift of the resonance frequencies of the BRDs over time, when stand alone or on the dummy BS. The frequencies are increasing by few hundreds of ppm per day. We see a stabilization in the drifts after about a month in the lab. The drift is slightly lower when the BRDs are mounted on the BS suspension compared to the stand alone BRDs in the lab. This could confirm that the excitation measurements cause some of the drift and we need to revise the method. We have no evidence that the baking process reduces the frequency drifts.

The measurements of the quality factor shows that the peaks may not be quite resolved, and that we are underestimating the Qs of the modes on the suspension. However, the value of the Qs in the stand-alone measurements is already promising.

 

Attachment 1: BRD1_drifts.png
BRD1_drifts.png
Attachment 2: Bounce_August2019_final.png
Bounce_August2019_final.png
Attachment 3: Roll_August2019_final.png
Roll_August2019_final.png
Attachment 4: BS_bounce_august_drift.png
BS_bounce_august_drift.png
Attachment 5: BS_roll_august_drift.png
BS_roll_august_drift.png
Attachment 6: August2019_monitoring.xlsx
  236   Wed Feb 26 11:24:35 2020 Marie K.SummaryBS BRDsBS Bounce mode : BRD5_v5 & BRD6_v5

====== Bounce Mode

Here is a summary of the BS bounce mode survey with BRD5_v5 and BRD6_v6 attached to the suspension for 6 months.
Details of the measurements are attached in the spreadsheet.

The measured transfer functions over time are shown in figure 1. We observed a single peak in the data. This is unexpected from our model.

  • There is no trend in the value of the resonant frequency.  The mean frequency is 16.660 Hz. The maximum excursion is +0.4% and the minimum is -0.2%.  
  • The Q of the mode is varying from 60 to 260, with no obvious correlation with the frequency variations. The maximum Q = 260 corresponds to a measurement with a lower amplitude of excitation (see elog xxx).

Therefore it seems that the bounce damping is pertty stable over 6 months. We didn't analyze correlations of the variations with environmental factors in the lab.

Measurements after taking off the BRD from BS:

Recall that pre-installation measurements were:

Attachment 1: BRD5&6_Winter_2019_survey_bounce_last.png
BRD5&6_Winter_2019_survey_bounce_last.png
Attachment 2: Picture1.png
Picture1.png
  237   Wed Feb 26 14:40:52 2020 Marie K.SummaryBS BRDsBS Roll mode : BRD5_v5 & BRD6_v5

====== Roll mode

Here is a summary of the BS roll mode survey with BRD5_v5 and BRD6_v6 attached to the suspension for 6 months.
Details of the measurements are attached in the spreadsheet.

The measured transfer functions over time are shown in figure 1. We observed two peaks in the data. This is in agreement with our model if the tuning if the BRD is within 0.1% of the BS roll mode (see T1900846).

  • Trend .  The mean frequency is Hz. The maximum excursion is +% and the minimum is -%.  
  • The Q of the mode is varying from to. Correlation with the frequency variations.

Therefore it seems that the bounce damping is pretty stable over 6 months. We didn't analyze correlations of the variations with environmental factors in the lab.

Measurements after taking off the BRD from BS:

Recall that pre-installation measurements were: 


  248   Tue Nov 24 11:09:18 2020 Marie K.SummaryBS BRDsLHO BRDs ready for C&B

This morning I handed off the parts for the 5 LHO BRDs to Bob Cottingham at LLO for Clean&Bake (https://ics.ligo-la.caltech.edu/JIRA/browse/clean-10214)

The parts for each BRD are in separate containers (see pictures attached).

Here are the masses of each component in order to reassemble the BRDs after C&B:

  Roll   Bounce
  Copper Screw Washer Total [g] Copper Screw Washer Total [g]
BRD1 6.355 0.724 0.052 7.131 8.836 0.855 0.2 9.891
BRD2 6.393 0.839 0.05 7.282 8.816 0.844 0.2 9.86
BRD3 6.403 0.851 0.05 7.304 8.812 0.832 0.2 9.844
BRD4 6.372 0.85 0.05 7.272 8.88 8.49 0.2 17.57
BRD5 6.389 0.844 0.05 7.283 8.904 0.864 0.2 9.968
Attachment 1: 5_BRDS_C&B.jpg
5_BRDS_C&B.jpg
Attachment 2: Detail_1BRD_container.jpg
Detail_1BRD_container.jpg
Attachment 3: Load_C&B_1135.jpg
Load_C&B_1135.jpg
  249   Tue Nov 24 12:31:05 2020 Marie K. SummaryBS BRDsLHO BRDs monitoring

LHO BRDs:

I didn't observe frequency drifts during the month of assembly and monitoring in the Optics Lab. This is not expected from our experiments in the Modal Lab, but it makes the preparation for the sites BRDs easier.

BOUNCE: In anticipation to the frequency drifts, I had tuned the BRDs on the lower side of the target frequency. But the tuning didn't drift so I changed the masses last week for the bounce mode in order to be in the 1% target. The jumps in the curves below are due to retuning (on November 5th for BRD1, on November 20th for the other ones).

Roll: I didn't retune the Roll modes after assembly on October 20th. In the last days, I was experimenting with different ways to excite them (see pictures attached), so this is probably the cause of the slight drifts that we see.

 


 

Attachment 3: Shaker_plate.jpg
Shaker_plate.jpg
Attachment 4: Shaker_electronics.jpg
Shaker_electronics.jpg
  1   Thu Mar 20 09:06:52 2014 Calum Torrie ProgressAir Knife / NozzleThe green lantern

This is image of the 4 sectioned green lantern on the mock up quad at cit.

Actions

1) BA to complete cabling for use in chamber 

2) CT to clean & bake

3) KG to practice imaging. unit is in 318 Downs on quad mock-up.

image.jpg

  4   Sun Jun 8 10:16:27 2014 Norna Roberson, Harrison MillerProgressImproved HSTSSW rendering of revised HSTS

Harrison has put together a first look at what a revised HSTS with blades at middle mass might look like. This is a work in progress, some parts missing (magnet /flag assemblies etc.)

Attachment 1: HSTS_assembly_clean.JPG
HSTS_assembly_clean.JPG
  5   Thu Jul 3 14:46:07 2014 Harrison MillerProgressImproved HSTSSummer Week 1

This week was spent mainly finishing up designs for the new HSTS middle mass. The main tasks were:

  • design new clamps to hold wires coming from the top mass above
  • design a clamp that can hold two wires at the appropriate distance and attach to a single blade
  • finish redesigning the top plate. Make sure all slots and holes are in the appropriate places and that slots allow access (make sure one side of the wire assembly can fit through)

The top plate was basically done at this point, all that remained was to make sure all of the holes were the correct tap size and such. What required the most attention was clamps holding the wires from above. I made an initial design and added holes to the top plate such that the clamp could be attached from below. However, once these clamps were in place, I realized the wire separation was too small. I made a change that created an asymmetrical piece with a handedness but, after a discussion with Calum, I modified the top plate so that we could go back to the symmetric design and maintain the correct wire seperation.

clamp_assem.JPG

 

As for the clamps on the blades holding the bottom mass, I adapted a previous design to not only maintain the wire separation, but also to account for the new angle of the wires (previously the wires from the middle mass down to the bottom mass were vertical, the addition of the blades doesn't allow for this)

  6   Thu Jul 3 14:56:08 2014 Harrison MillerProgressImproved HSTSSummer Week 2

The main goal for this week was to start getting engineering drawings in order for fabrication. With Eddie's help, I drew up all of the parts in the new middle mass. After a couple rounds of red lines, I got the drawings to a near-finished state. I also got DCC numbers for all of these parts.

While doing this, I realized that I had not figured a way to attach the two bottom pieces (pictured below).

bottom.JPG

We decided brackets were the way to go, so I drew some up in solidworks, got another DCC number for them, and added them to the assembly.

I also began a Bill of Materials for the new middle mass

 

  7   Thu Jul 3 15:04:39 2014 Harrison MillerProgressImproved HSTSSummer Week 3

I had a few things left over from last week to finish up early this week, like finishing a few engineering drawings and fleshing out the Bill of Materials (I have attached its state so far to this entry). I also made a drawing of the new blades for this mass using the parameters Norna found.

In addition, I added in a roll adjuster similar to the pitch adjuster and added tapped holes for set screws to hold the adjusters in place.

Norna, Calum, and I met on Thursday to discuss what I'd be doing for the next couple of weeks. The tasks we settled on are as follows:

1) Finish Bill of Materials (BOM). Finish getting DCC numbers. Put onto Vault(?)
2) Write up what you have done in the design and explain why. Could add to existing document.
3) Blade design/ drawing . Also FEA of blade. See Calum's reference.
4) Work with Eddie to get quotes for parts. Write statement of work. Could also get quotes for rapid prototype version.
5) Put together rendering of whole suspension including bottom wires going round mass - use a glass mass.
6) Adjust length of bottom wires to get the orignal overall lenght of HSTS. Note new length
7) Look into redesign of wire jig for producing clamp/wire clamp assembly to take your new clamp design. Draw up modification.
8)  FEA of new mass - basic modes in free / free case cf top mass also look at adding loads to represent blades
9) Get set-up going to measure  mode frequencies of triple suspension  in lab Could use B&k or spectrum analyzer - need to think about non-contact probe or accelerometer ( this item  in conjunction with Norna /Calum).
10) deep fallback - resurrect Kristen's middle mas for HLTS and apply design considerations used in HSTs to continue that design.

I forgot to make drawings of the T-section and I-section, I need to do that as soon as I return after the holiday weekend

Attachment 1: HSTS_Middle_Mass_BOM.xlsx
  8   Fri Jul 11 15:52:42 2014 Harrison MillerProgressImproved HSTSSummer Week 4

This week I tackled items 1-3 on the to do list I got last week.

All of the parts I have drawn for the new HSTS middle mass have been added to a sandbox file on the vault. I have also summarized all of the work done so far on the new middle mass in a review document on the DCC (found here). Finally, I began running FEA on the new blade design to A) find its normal modes and B) make sure the deflection we calculated was accurate. The findings of that analysis are in a report on the DCC (found here). At first, the deflection was not looking correct, but after consulting with Calum and reviewing an FEA he ran on some other blades, I realized I had entered my loading conditions wrong. I corrected them and got the following deformation.

flatblade.JPG

I'll begin next week with doing FEA on the entire mass and adding all the FEA results to the overall report. Hopefully we will also begin getting quotes for parts

  9   Thu Jul 24 10:37:06 2014 Harrison MillerProgressImproved HSTSSummer Week 5

I forgot to enter this on the 18th, so here is what I did the week ending on the 18th.

I completed FEA of the overall middle mass and found the "wing mode." It occurred at 217.03 Hz.

wing.JPG

 

I have begun on a rendering of the HSTS with the new middle mass. In doing so, I have realized that the clamps on the middle mass do not quite line up with the wires. I have done some tweaking and we will see when Norna returns if the fix is acceptable.

We also began work on the mini-project Calum presented to us. I have some preliminary designs, but I'd like to get my hands on some of the mesh I want to use to get a feel for it.

  10   Wed Nov 25 12:11:13 2015 Calum TorrieProgressThomasPumping down on Quad Nov 25th

Pumping down on Quad Nov 25th.

With Vac at 2.15e-5 Torr ran B&K system for 256s with 1 average. df=3.9 m Hz. Re-ran Graphical Setup in Trigger and changed hold off to 100 from 1000s.

 

  11   Wed Sep 28 09:59:39 2016 AlenaProgressThomasSR3 actuator test

Goal: thermal conductivity test depending on pressure

Setup: no gasket at the ring heater; no thermal pad on the thermocouple, thermocoupel at the center of the back plate

Current: 200 mA

Expected max temperature: 130 C

Pressure: 2 10-6 torr - 8 10-8 torr

I measured the temperature during 3 days at constant current just to if there is any influence of the pressure on the result.

Result: The temperature measurement in future can be started at low 10-6 torr range (an overnight pump down for Thomas vacuum chamber)

 

Attachment 1: 20160927_150026.jpg
20160927_150026.jpg
Attachment 4: pressure_test_.png
pressure_test_.png
  12   Fri Sep 30 08:19:19 2016 AlenaProgressThomasSR3 actuator test

Goal: cheking repetability of the tempreture elevation

Setup: no gasket at the ring heater; no thermal pad on the thermocouple, thermocoupel at the center of the back plate

Current: 250 mA

Expected max temperature: 200 C

Pressure: 2 10-7 torr

Increasing resistance with temperature (decreasing current):

Attachment 1: 189.jpg
189.jpg
  13   Fri Sep 30 11:59:38 2016 AlenaProgressLaser DamageProcedures and older logs

This is a new log started on Sept 30 2016. For the older logs and procedures please see https://dcc.ligo.org/LIGO-T1600205

  14   Fri Sep 30 12:16:23 2016 AlenaProgressLaser DamageViewport cover

The modified Viewport cover was installed using the new adapter ring. No leaks. Pump down looked Ok.

 

Attachment 3: 2.jpg
2.jpg
  15   Mon Oct 3 07:59:46 2016 AlenaProgressThomasSR3 actuator test

Goal: cheking contact at thermo couple is ok ore needs improovement

Setup: no gasket at the ring heater; indium thermal pad on the thermocouple, thermocoupel at the center of the back plate

Current: 189(207), 250(258), 300 mA - 7:30 AM, 11:30 AM, 3:30 PM

Expected max temperature: 220 C

Pressure: 2 10-7 torr

Results: The temperature measured with the thermocouple almost did  not change by adding indium foil between the washer and the gold plated plate (red curve). Hovewer the temperature at the ring heater changed. A second run with no indium (after reassembling the setup) shown a consistent temperature at the gold plated surface and again completely different temperature at the ring heater. Pressure was the same during all three measurement.

  17   Thu Oct 6 10:56:01 2016 AlenaProgressThomasSR3 actuator test

Goal: comparison of the temperature at the center of the gold plated plate during two runs: without gasket and with In gasket

Setup: thermocouple at the center

Current: 190, 250 and 300 mA

Expected max temperature: 200 C

Pressure: 2 10-6 torr

In pad under the thermocouple washer after the first run :

Mounting the indium gasket

Results: This two runs did not demonstrate the same dramatic improvement by adding the gasket as previously. The most probable reason is the decreased compression because of adding a thermocouple with a washer to the assembly. Another confirmation of the bad compression is higher ring heater temperature comparing to previous runs.

 

Attachment 1: unnamed.jpg
unnamed.jpg
Attachment 6: repetability_test.png
repetability_test.png
  18   Tue Oct 11 13:35:00 2016 AlenaProgressThomasSR3 actuator test

Goal: comparison of the temperature at the center of the gold plated plate during two runs: with 4 and with 3 washers (part #4 per D1500387)

Setup: thermocouple at the center, In gasket

Current: 190(207), 250(258) and 300(308) mA

Expected max temperature: 200 C

Pressure: 4 10-7 torr

Using 3 washers instead of 4 improves the thermal contact. The temperature at the thermocouple did not change but the ring heater doesn't warm up as hot as before.

Attachment 2: less_washers_test.png
less_washers_test.png
  20   Thu Oct 13 14:36:14 2016 AlenaProgressThomasSR3 actuator test

Goal: Position dependent measurement of the temperature at the plate.

Setup: thermocouple next to the center with capton tape

Current: 190, 250 and 300 mA

Expected max temperature: 200 C

Pressure: 5 10-6 torr

I moved the thermocouple from the center because it's washer changes the amount of compression and the measurement it difficult to compare with other once. Also the bump at the washer makes holes in the plating if everything is tighten. The measurement shows that more compression is needed (less washers)

  34   Wed Jan 4 14:08:46 2017 AlenaProgressLaser DamageFused silica viewport

Measured lasaer power at the end of the layout with defould pyrex viewport, fused silica AR coated viewport and no viewport. See https://dcc.ligo.org/T1700003-v1 for more info.

Laser power measured using a “PM100USB” power meter and an S314C sensor (±3% measurement uncertainty at 1064 nm). Gray dots represent the power indicated at the laser display which can be inaccurate. There are additional mirror losses at the beam transport via RTS setup. That is why power at LDF setup location will differ from the values shown on the laser display.

Black curve on figure1 is the power measured at the end of the LDF laser layout (including a window from the viewport cover) with no viewport (figure 2). Blue and red curves represent the power measured with a fused silica and pyrex glass correspondently. In both cases the glass was added at the end of the laser layout (see figure 3).

Figure 1: 1064 laser power measured as a function of the input value

Figure 2: Power-meter installed at the end of the LDF laser layout (correspond to the black curve on figure 1)

Figure 3: Power-meter installed at the end of the LDF laser layout plus the fused silica glass (correspond to the blue curve on figure 1)

Almost 100% transmission trough the fused silica viewport has been observed. Losses in fused silica were less that the resolution of the power meter. In contrast, losses up to about 15% were observed in the pyrex glass. An integrating sphere may be used for more accurate measurement.

Calibration function between the display input and the power in vacuum chamber after passing the viewport (±3% measurement uncertainty in not considered):

PLDF[W]=-4.796812+ 0.549683 Pdisplay input [%]

 

 

 

 

  35   Thu Jan 12 07:36:55 2017 StephenProgressCASI BRDFGigE Camera: Photos of Oxidized SSTL

This log entry reflects on recent efforts to image the 1064nm spot on samples undergoing BRDF measurement within the CIT CASI scatterometer. The cameras used are (reiterating from eLOG ENG_Labs/33)

  • Basler ace acA640-100gm, same as used at sites, borrowed from Johannes at 40 m. Equivalent to acA640-120gm, which is the current Basler designation of this camera.
  • Basler scout scA1400-17gc, originally purchased by OpLev design team, leftover from aLIGO efforts, borrowed from Eric/Gabrielle in West Bridge.

The set up and measurement is described by the following procedure:

  1. A sample of oxidized stainless steel was found in the lab and taped to an existing sample mount using kapton tape.
  2. Images were taken with the room lights on and then without the room lights.
  3. Imaging settings were maintained for each photo taken with an individual camera, but gain values and packet size varied between cameras.

Hardware for the cameras included:

  • a lens with adjustable focus (Rainbow, 50mm focal length, C mount, 2/3" to 1" aperture, 1:1.8 image; 40m loan)
  • where indicated, a ~70% transmissive bandpass filter (Newport 10LF25-1064).
  • mounting post with fixed clamping platform (will add photo), approximately 1 meter from the sample.

The acquired images may be summarized by the following points:

  • The 1064nm light was represented by the color scout camera as white-ish pixels with a bluish tinge.
  • The scout camera appeared to have a number of dead pixels (someone with more camera expertise may have better terminology; I am referring to the scattered red and blue pixels that do not appear to be real light).
  • The focal length of the two cameras was different, hence the difference in perceived spot size.
  • The bandpass filter reduced intensity of the image and, with the light off, did not seem to provide any useful noise cancelling.

Image 07: Lights on, scout OpLev GigE Camera Link to casi_test_07_laptop_lights_high_exposure_10_mw_high_gain.bmp

Image 08: Lights off, scout OpLev GigE Camera Link to casi_test_08_no_lights_high_exposure_10_mw_high_gain.bmp

Image 09 Lights off, bandpass filter, scout OpLev GigE Camera Link to casi_test_09_no_lights_high_exposure_10_mw_high_gain_bandpass_filter.bmp

Image 13: Lights on, ace Site GigE Camera Link to casi_test_13_site_gige_foyer_light_auto_exposure_10_mw_auto_gain.bmp

Image 15: Lights off, ace Site GigE Camera Link to casi_test_15_site_gige_foyer_light_auto_exposure_10_mw_100_gain.bmp

Image 19: Lights off, bandpass filter, ace Site GigE Camera Link to casi_test_19_site_gige_no_light_auto_exposure_10_mw_100_gain_bandpass_filter.bmp

Attachment 1: casi_test_07_laptop_lights_high_exposure_10_mw_high_gain.bmp
Attachment 2: casi_test_08_no_lights_high_exposure_10_mw_high_gain.bmp
Attachment 3: casi_test_13_site_gige_foyer_light_auto_exposure_10_mw_auto_gain.bmp
Attachment 4: casi_test_15_site_gige_foyer_light_auto_exposure_10_mw_100_gain.bmp
Attachment 5: casi_test_09_no_lights_high_exposure_10_mw_high_gain_bandpass_filter.bmp
Attachment 6: casi_test_19_site_gige_no_light_auto_exposure_10_mw_100_gain_bandpass_filter.bmp
  37   Wed Apr 5 13:12:57 2017 AlenaProgressPZT jitter experimentRed v-block test

PZT`s transfer function measurement with a test v-block was done in tree differen configurations:

- no viton (blue curve)

- viton under PZT (orange curve)

- viton only under the front part of the PZT (green curve)

Conclusion: 3rd configuration is the winner. It provides stiff clamping of the back of the PZT plus dumping. Need to design new v-block type mount with two clamps. Promissing first resonance at 3kHz with the new mount

 

  38   Wed Apr 5 13:27:30 2017 AlenaProgressPZT jitter experimentD1700002 v-block test

New mount has been reworked  https://dcc.ligo.org/D1700002 in order to use 2 v-lamps. See modefied mount https://dcc.ligo.org/LIGO-D1700002-v5

See T1600060 the transfer function measured with four different configurations: - elliptical mirror, no viton (black curve)
- elliptical mirror, viton under tip of the PZT (blue curve)
- elliptical mirror, viton (full length) (green curve)
- 2" mirror, viton (full length) (red curve)

First resonance appears at about 2 kHz which is very close to the internal resonance frequency of the PZT (3 kHz with no load according to the specs). Adding viton in the grove did not dump the resonance (black curve vs green and blue) however it can be an option. Changing the mirror from 2" to a lighter elliptical is still a significant improvement even with the new mount (red curve vs others).

 

  41   Mon May 1 17:14:41 2017 AlenaProgressLaser DamageFused silica viewport laser damage test

Worked on a laser layout for in-air fused silica viewport optic laser damage test. Made a temporary enclosure to prevent high power laser scatter and to stop any possible fragments of potentially damaged viewport. A “labyrinth” shape was built instead of making holes for the laser tube. The top of the enclosure will be covered with one large black panel as well. The beam was focused to 2w=100 microns at the position of the target (red line)

Attachment 1: 20170501_163511.jpg
20170501_163511.jpg
  42   Wed May 3 17:20:24 2017 AlenaProgressLaser DamageFused silica viewport laser damage test

Added a magnetic base for the 3" diameter target mount. The mount is angled in order to dump the reflection from uncoated fused silica target. Beam on the target is 127 by 91micron ellipse. Irradiation is planned at 25, 50, 75 and 100% power (100%=50W). Equivalent power densities and irradiation runs see in the dcc doc https://dcc.ligo.org/S1700118-v1

Attachment 1: unnamed.jpg
unnamed.jpg
  43   Fri May 12 16:34:54 2017 AlenaProgressLaser DamageFused silica viewport laser damage test

Made series of laser irradiation on a 3” fused silica uncoated optic https://dcc.ligo.org/LIGO-S1700118-v4

The optic is planned to be used as a viewport at LDF. In air laser damage test is required before using the optic as a viewport on the LDF vacuum chamber. Beam on the target is 127 by 91 microns ellipse. See estimated equivalent laser power input table and layout picture in the related doc https://dcc.ligo.org/LIGO-T1700184-v1

No damage was observed using DF microscope. The inspection was done using manual control – no scanning. After each irradiation run a picture was taken with a FLIR camera.  Post irradiation pictures taken with DF microscope are posted herte https://dcc.ligo.org/LIGO-S1700118. 

Warming up of the beam dumps up to 57 deg C was detected. No other elements of the set up were changing temperature (including the target – 3” fused silica optic and it`s mount)

  53   Mon May 14 10:57:43 2018 Stephen AppertProgressElectric Field MeterMechanical Part History and Serial Numbers

WIP (photos will be posted, more information will be gathered)

  1. 14 May 2018: Stephen and Luis gathered serial numbers from Cube 2 / Cube 3 / spares (all of which were Class A baked in Bake-9049) (ICS records will be updated)
    1. Cube 3
      1. D1800043-v1 SN003
      2. D1800032-v2 SN013
      3. D1800032-v2 SN004
      4. D1800032-v2 SN001
      5. D1800032-v2 SN012
      6. D1800054-v1 SN002
      7. Cube 408003 unserialized
    2. Cube 2
      1. D1800043-v1 SN004
      2. D1800032-v2 SN009
      3. D1800032-v2 SN010
      4. D1800032-v2 SN002
      5. D1800032-v2 SN014
      6. D1800054-v1 SN003
      7. Cube 408003 unserialized
    3. Spares
      1. D1800032-v2 SN011
      2. D1800032-v2 SN007
  73   Fri Jul 20 22:19:15 2018 Alena, KyleProgressStray Light ControlOFI roofless shroud fitcheck

A rough OFI shroud fitcheck was done on a earlier version of the structure. We found out a lot of issues with various types custom hardware. Most common problem - tapped not all the way through where it needs to be (D1700233, D1700244), bad threads on D1800111. The hardware has been re-tapped with clean taps.

Some photos of the assembled shroud are attached (did not use viton and coated hardware for the fit check because some parts were still at the C&B etc.)

Attachment 1: 20180706_182326.jpg
20180706_182326.jpg
Attachment 2: 20180706_180825.jpg
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Attachment 3: 20180706_180853.jpg
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Attachment 4: 20180706_180859.jpg
20180706_180859.jpg
  74   Sun Jul 22 23:32:38 2018 Kavya SreedharProgressFast ShutterMagnetic Field of Rectangular Coil with Ansys

I designed a rectangular shaped coil loop with 1A of current building off of an Ansys tutorial and generated a solution which plotted the magnetic field due to the coil. The attached pictures show the magnetic field magnitude and the magnetic field vector from various angles of viewing the coil. The thicker and smaller arrows signifying the magnetic field vector represent the same magnetic field and the thickness of the arrows does not indicate anything about the field; both pictures are included just for ease of viewing and interpretation. As expected for a current carrying loop, the magnetic field lines appear to go through the coil and loop around the sides and the field seems stronger in the center of the coil compared to the outside magnetic field loops.

Next steps with this design include estimating field strength expected from such a coil and verifying those calculations with these simulation results as well as designing a similar project for a circular coil and then also a coil that matches the shape and measurements of those used for the fast shutter. After generating the magnetic field for one coil used for the fast shutter, the field due to two such identical coils placed next to each other can be modeled as well.

Project Name : Coil_practice | Design Name: Rectangular_coil (Magnetostatic)

Attachment 1: rectangular_coil_B_field_magn.png
rectangular_coil_B_field_magn.png
Attachment 2: rectangular_coil_B_field_bigger_arrows.png
rectangular_coil_B_field_bigger_arrows.png
Attachment 3: rectangular_coil_B_field_smaller_arrows.png
rectangular_coil_B_field_smaller_arrows.png
Attachment 4: rectangular_coil_B_field_back_side_view.png
rectangular_coil_B_field_back_side_view.png
  75   Tue Jul 24 22:44:16 2018 Kavya SreedharProgressFast ShutterMagnetic Field of Circular Coil with Ansys

Similar to the rectangular coil posted earlier, I desiged a circular coil loop with 1A of current and generated a solution which plotted the magnetic field due to the coil. The attached pictures show the magnetic field magnitude and the magnetic field vector from various angles of viewing the coil. As expected for a current carrying loop, the magnetic field lines appear to go through the coil and loop around the sides and the field is stronger towards the center of the coil compared to the outside magnetic field loops, which is consistent with the magnetic field from the rectangular loop simulation. A Boolean union of parts of the geometries used to construct the rectangular and circular coil can be used to design the geometry for the coils part of the fast shutter so that those magnetic fields can be modeled as well.

Project Name : Coil_practice | Design Name: Circle_coil (Magnetostatic)

Attachment 1: circular_coil_B_field_magnitude.png
circular_coil_B_field_magnitude.png
Attachment 2: circular_coil_B_field_vector_front.png
circular_coil_B_field_vector_front.png
Attachment 3: circular_coil_B_field_vector_back.png
circular_coil_B_field_vector_back.png
Attachment 4: circular_coil_B_field_vector_angle.png
circular_coil_B_field_vector_angle.png
  76   Thu Jul 26 22:54:44 2018 Kavya SreedharProgressFast ShutterMagnetic Field of Fast Shutter Coil (1 turn) with Ansys

Magnetic field magnitude and vector solution generated for a coil with the dimensions of a coil part of the Fast Shutter with 1 turn and 1A of current. As we saw for the circular and rectangular coil models in Ansys, the magnetic field lines for this model also go through the coil and loop around the sides and the magnetic field is stronger in the center of the coil compared to the outside magnetic field loops for this coil as well. Next steps include exploring how to add more turns to the model as well as placing 2 of these coils next to each other to more accurately model the current Fast Shutter setup.

Project Name: Coil_Practice | Design Name: Fast_shutter_one_coil (Magnetostatic)

Attachment 1: B_field_magnitude.png
B_field_magnitude.png
Attachment 2: B_field_vector_back.png
B_field_vector_back.png
Attachment 3: B_field_vector_front.png
B_field_vector_front.png
  87   Mon Oct 1 13:39:07 2018 Kavya SreedharProgressFast ShutterFast Shutter Magnetic Field Model in Comsol

Little late on the update, but modeled the magnetic field of the fast shutter coil in Comsol (it previously had been modeled in Ansys). Both coils were modeled as single conducors with 1A of current with the appropriate dimensions and attached is the picture of the magnetic field density/field. As we would expect, the magnetic field and magnetic flux density as shown in the picture are strongest in between the two coils and drop off on the outside sides of both coils and the picture fits with intuition. In future posts, I will be uploading pictures of the coils modeled as homogenized multi-turn coils with the ability to adjust number of turns as well as the addition of a magnet moving in between the two coils to model our current fast shutter system setup.

Attachment 1: Capture.PNG
Capture.PNG
  93   Fri Nov 2 09:42:43 2018 Don GriffithProgressHSTS-Bolted v. Welded StructureHSTS Boltable Structure with Test Plates

The Boltable Structure assemby (D1101986) has been modified to accept Test Plates (D1800232) for vibration testing.

The new "Boltable Structure with Test Plates" assembly (D1800237) has been assembled and all bolts have been torqued to spec.

The assembly is in the Modal Lab and is ready for testing. See attached picture.

Attachment 1: Boltable_Structure.jpg
Boltable_Structure.jpg
  Draft   Mon Nov 5 23:03:29 2018 Kavya SreedharProgressFast ShutterStationary Model Update + Projected Next Steps

Added in the NdFeB magnet used in the lab into the Comsol simulation model in order to get a reasonable stationary model with the magnet and two coils. The two coils have been updated to be homogenized multi-turn coils with 500 turns as in our current physical setup and currently have 1A of current each.

The flux density and field for the coils and the magnet are plotted in the below pictures and I am currently in the process of checking with Comsol about how the magnet's magnetic field arrows are not drawn as we would expect (looping from one end to another) and whether that's a limitation of how the arrows are drawn or of the model. With this model, the force has been calculated as a function of the magnet's location in the z-direction (moving up and down between the coils) and pictures of that will be posted soon as the plotting settings are sorted out. For now, a picture of the force calculated on a rectangular model from the Comsol training Rich went to is attached.

Next steps with this model are to verify whether the lifting force for the magnet from the simulation compares with the gravitational force calculated and magnetic force determined from lab with the physical setup of the first generation fast shutter (by measuring the current required) so that we have an indication of whether the simulation accurately represents what has been measured with the physical setup in lab. After that confirmation, next steps are to understand the impact of changing the magnet geometry on the force required to lift the magnet and in particular see what effect changing the thickness and length of the magnet have and whether there is a limiting point at which the addition of mass of a magnet as we increase a dimension outweighs any advantage we may gain by having more of the magnet to be affected by the coils' magnetic fields. The biggest change to introduce to this stationary model in the coming weeks is the modeling of the response when current is initially applied to the coils which will have some rise time till it reaches its intended value due to the inductance of the coils. An external circuit modeling this inductance will need to be added to this model so that we can determine the force necessary to overcome this inductance and the optimal magnet geometry for that. Thus, the three main upcoming goals are 1) verify lifting force for magnet in simulation matches what was measured in lab, 2) understand optimal magnet geometry, and 3) understanding the transient model before we reach steady-state.

Attachment 1: Capture.PNG
Capture.PNG
Attachment 2: Capture2.PNG
Capture2.PNG
Attachment 3: Capture3.PNG
Capture3.PNG
  110   Fri Feb 1 16:30:52 2019 StephenProgressModal TestingVMD: non-excitation characterization

Contributors: Craig, Alexei, Stephen

Project: VMD Testing (BK Connect)

Summary: Non-excitation measurements by laser vibrometer were successful. We will work on curve fitting the spectra to extract Qs, but this technique seems to work well.

Description

The following measurements have been made:

  • Bolted-base non-excitation measurement in the transverse direction
  • Glued-base non-excitation measurement in the transverse direction
  • Glued-base non-excitation measurement in the longitudinal direction

Remember, our bolted-base excitation measurement in the longitudinal direction was poor, so we did not feel like the non-excitation measurement would be informative.

We made measurements of a field calibrator reference, which oscillates at 159.2 Hz at a velocity of 10 m/s. We measured the velocity of this peak using a separate setup within our VMD Testing project, using 2 vibrometers. We adjusted the sensitivity of each vibrometer in our hardware table using the proportional relationship:

[Old Sensitivity * (Measured Velocity / Nominal Velocity)] = [New Sensitivity]

We then collected non-excitation measurements in two directions at once using the two calibrated vibrometers, and then swapped the response direction of each vibrometer to make a second measurement. There was good agreement between the two vibrometers, and the technique seemed very promising for resolving the peaks fully.

We investigated comparison with the autospectrum of the excitation measurements, and we'll tie up lose ends on that - seems like a visual check of the shape and the prominence of the resonance peak will be a good way to confirm that this technique is working.

Next Steps

  1. Craig - Finalize plots of non-excitation measurements and push to next rev of T1800474
  2. Craig - Look into matlab curve fitting toolbox - looking to extract Q from noisy non-excitation measurements

Photos/Figures

None to share this time - oops!

  112   Mon Feb 4 16:07:59 2019 AlexeiProgressModal TestingPMC Bounce Mode Testing

Contributors: Alexei, Stephen

Project: PMC Bounce Mode Testing

Summary: PMC body mode testing performed with kinematic mounts and no kinematic mounts (bolted directly to breadboard with mounting blocks).

Description:  A variety of vibrometer modal measurements were taken to test the PMC bounce modes.

  1. A degree of freedom setup was used to produce the attached video files that describe the mode shapes seen of the PMC body.
  2. Damped and undamped PMC measurements taken with a control measurement (z-excitation in center of PMC body).  Showed characteristic flex mode of the pmc (~1600 Hz) and two smaller features at a lower frequency (~200 Hz)
  3. Kinematic mounts removed and PMC bolted directly to breadboard using mounting blocks.  One of the lower frequency features may have disappeared, data somewhat unclear.

Next Steps: 

  1. Perform another z-excitation measurement of pmc body w/o kinematic mounts that is damped with appropriately sized viton padding.
  2. Attempt to resolve odd features seen in measurements from pmc body w/o kinematic mounts. Possible double feature remains or if bounce mode eliminated.  

Photos/Figures:

Relevant Links: https://dcc.ligo.org/DocDB/0126/D1600227/011/D1600227-v11.PDF

https://alog.ligo-wa.caltech.edu/aLOG/uploads/42087_20180520171341_Figure10-70W-And-PMC-Mounting-50X-motion.pdf

 

 

Attachment 1: PMC_Bounce_Mode_Testing_pmc_dummy_with_kinematic_mounts_mode_shape_mode01_rocking_maybe.avi
Attachment 2: PMC_Bounce_Mode_Testing_pmc_dummy_with_kinematic_mounts_mode_shape_mode02_bounce.avi
Attachment 3: PMC_Bounce_Mode_Testing_pmc_dummy_with_kinematic_mounts_mode_shape_mode03_flex.avi
Attachment 4: Viton_damping_placement.jpg
Viton_damping_placement.jpg
Attachment 5: Bolted_setup.jpg
Bolted_setup.jpg
Attachment 6: Kinematic_Mount_placement.jpg
Kinematic_Mount_placement.jpg
Attachment 7: PMC_Bounce_Mode_Testing_Vibrometer_setup.jpg
PMC_Bounce_Mode_Testing_Vibrometer_setup.jpg
Attachment 8: PMC_Bounce_Mode_Testing_low_frequency_comparison.JPG
PMC_Bounce_Mode_Testing_low_frequency_comparison.JPG
Attachment 9: PMC_Bounce_Mode_Testing_Full_spectra_comparison.JPG
PMC_Bounce_Mode_Testing_Full_spectra_comparison.JPG
  113   Mon Feb 4 16:08:00 2019 StephenProgressOCF CavityEddy Current Damping - Mechanical Design and Magnet Characterization

Contributors: Stephen, Rich

Project: Optical Cavity Eddy Current Damping (see 120)

Summary: Mechanical design shared with Rich (Dean unavailable). Quotes obtained from Proto Labs for machined parts. Surface Field of Ni-plated ND42 magnets was measured and compared with magnets from prototype.

Description:

Mechanical Design

  • Looked at D1900070 OCF ECD design with Rich, Dean was out today otherwise would've met with him as well. We discussed adjustment degrees of freedom, assembly technique, vacuum compatibility, and came away with no snags or issues.
  • I am working on posting the minimum design documentation to share the design and potentially even move toward fabrication if needed (.stp files exported for quotations, .easm solid models for visualization and docuementation including dimensions, BOM, etc). Formal part drawings are outstanding at this time.

Characterization of Magnets

  • Magnets have arrived from K&J Magnetics (P/N SD64-OUT, see C1900105). Material is Ni-plated ND42 - nominal surface field is ~5000 Gauss.
  • The nickel plating looks very bright and uniform, and the dimensions are very consistent (and in conformance with manufacturer spec)
  • The surface field parameter was inspected with Rich using a PCE Hall Effect probe (AC/DC MAGNETIC METER Model: PCE-MFM 3000) within 5% of nominal on 5 articles of this SD64-OUT magnet.
  • For comparison, one of the magnets from the ECD prototype (material and sourcing unknown, borrowed from Calum) was found to have surface field ~3000 Gauss.

Modal Testing

  • With Alexei on spring break, we are still working toward updating plots and findings from ENG_Labs log 120. No progress to report there, but success

Next Steps:

  1. Bob, Calum, Dean, Rich, Stephen will meet to discuss the OCF path ahead and as part of that discussion will make a plan for fabricating and implementing the ECD.
  2. E1000193 OCF Log item OCF001, Acrylite-coated optical fiber S1900194, is done with C+B processing (approval?) and might need to go into an OCF cavity before the ECD is ready.

Photos/Figures

N/A

  117   Thu Feb 14 15:48:26 2019 CraigProgressModal TestingVMD Review Questions

The following questions I came up with after listening in to the VMD design review on 2/13/2019

1) One method of tightening the VMD assembly is the allen key pattern in the top of the copper rod. If this process of tightening the assembly needs to be repeatable, how will the distortion of this pattern be taken into account? Just in the lab, the during re-assembly there has become noticeable distortion of this key pattern making it difficult to obtain the correct torque when tightening the assembly. 

2) I believe I heard there can be a +/- 1 Hz difference in resonance frequencies between Air/Vacuum, but how will epoxy react to this difference? Also, is there concerns of outgassing of the epoxy?

I hope to have those questions clarified by Stephen/Calum next week

  120   Mon Feb 25 16:53:21 2019 AlexeiProgressModal TestingOptical Cavity Eddy Current Damping

Work in Progress

Contributors: Alexei, Stephen

Project: Optical Cavity Eddy Current Damping Mode Testing (BK Connect)

Summary: Non-excitation, transverse, and longitudinal excitation measurements by laser vibrometer (OMC and Ometron).  Recordings taken and fitted with fft spectrum to compare damping effects of different magnet configurations used for eddy current damping.

Description

The following measurements have been made:

  • No-excitation measurement in the transverse/longitudinal direction
  • Longitudinal excitation measurement undamped / 1.5mm damping / 3mm damping / 2 magnet centerline damping
  • Transverse excitation measurement undamped / 1.5mm damping / 3mm damping / 2 magnet centerline damping
  • Transverse/Longitudinal huddle tests

The pendulum mode of the optical cavity assembly was recorded when the assembly was undamped, damped by 4 magnets oriented at 45 degrees from the horizontal and with 2 magnets oriented along the centerline.  Distance of the magnets from the copper sheeting of the cavity was also tested (magnets kept at distance of 1.5mm and 3mm).

Note: OMC laser vibrometer has issue of signal LED having gone out. Prompted huddle tests.

Next Steps

  1. Alexei/Stephen - Finalize documentation from attached plots.  Calculate and compare Q's from fft spectra.

Photos/Figures

See attached

Attachment 1: Optical_Cavity.JPG
Optical_Cavity.JPG
Attachment 2: Optical_Cavity_mock_assembly.JPG
Optical_Cavity_mock_assembly.JPG
Attachment 3: Lab_setup_1.JPG
Lab_setup_1.JPG
Attachment 4: 4_magnet_damping_assembly.JPG
4_magnet_damping_assembly.JPG
Attachment 5: 4_magnet_side_view.JPG
4_magnet_side_view.JPG
Attachment 6: 2_magnet_damping_assembly.JPG
2_magnet_damping_assembly.JPG
Attachment 7: 2_magnet_side_view.JPG
2_magnet_side_view.JPG
Attachment 8: Transverse_undamped.MOV
Attachment 9: Transverse_damped.MOV
Attachment 10: Optical_Cavity_longitudinal_no_excitation_fft_spectrum_low_frequency_peaks.JPG
Optical_Cavity_longitudinal_no_excitation_fft_spectrum_low_frequency_peaks.JPG
Attachment 11: Optical_Cavity_longitudinal_no_excitation_fft_spectrum_higher_frequency_peak.JPG
Optical_Cavity_longitudinal_no_excitation_fft_spectrum_higher_frequency_peak.JPG
Attachment 12: Optical_Cavity_transverse_excitation_fft_spectrum.JPG
Optical_Cavity_transverse_excitation_fft_spectrum.JPG
Attachment 13: Optical_Cavity_longitudinal_excitation_fft_spectrum_peak_2.JPG
Optical_Cavity_longitudinal_excitation_fft_spectrum_peak_2.JPG
Attachment 14: Damped_2_magnets_centerline_comparison_longitudinal_excitation.JPG
Damped_2_magnets_centerline_comparison_longitudinal_excitation.JPG
Attachment 15: Damped_2_magnets_centerline_comparison_transverse_excitation.JPG
Damped_2_magnets_centerline_comparison_transverse_excitation.JPG
  121   Tue Feb 26 11:04:27 2019 StephenProgressModal TestingOptical Cavity Eddy Current Damping

Looking at this work, the next step will be to re-generate plots with (1) improved resolution [Q should be resolved with (3dB width) > (10*resolution), if possible!] and (2) on longitudinal scales (either physical units or dB) to enable qualitative visual comparison. (also, I think the longitudinal movies you took didn't get posted?)

The following step would be to make a quantitative comparison of Q - see below table, intended as a mockup of the important information to summarize.

The key outcome of this effort is assessing whether the prototype damping scheme is working, and if so, what degrees of freedom should be incorporated into the final design of the damper. Hope this helps clarify why these requests are being made!

Comparison Table Mockup
Resonance Frequency (Hz) Prominent Direction (Long/Tran) Mode Shape Description Measurement technique Undamped 3 dB width (Hz) Undamped Q Best damped 3 dB width (Hz) Best damped Q

Best damping parameters

Resolution of FFT (Hz)
2.337 Transverse  Primary Pendulum Excitation, non-excitation .0163   .0241   1.5 mm spacing, 4 magnets, V .0125
2.438 or 2.425 Longitudinal Primary  Pendulum Excitation, non-excitation .0173   .0332   1.5 mm spacing, 4 magnets, V .0125
13.338 or w/e is next     Excitation, non-excitation (?)            
Quote:

Work in Progress

Contributors: Alexei, Stephen

Project: Optical Cavity Eddy Current Damping Mode Testing (BK Connect)

Summary: Non-excitation, transverse, and longitudinal excitation measurements by laser vibrometer (OMC and Ometron).  Recordings taken and fitted with fft spectrum to compare damping effects of different magnet configurations used for eddy current damping.

Description

The following measurements have been made:

  • No-excitation measurement in the transverse/longitudinal direction
  • Longitudinal excitation measurement undamped / 1.5mm damping / 3mm damping / 2 magnet centerline damping
  • Transverse excitation measurement undamped / 1.5mm damping / 3mm damping / 2 magnet centerline damping
  • Transverse/Longitudinal huddle tests

The pendulum mode of the optical cavity assembly was recorded when the assembly was undamped, damped by 4 magnets oriented at 45 degrees from the horizontal and with 2 magnets oriented along the centerline.  Distance of the magnets from the copper sheeting of the cavity was also tested (magnets kept at distance of 1.5mm and 3mm).

Note: OMC laser vibrometer has issue of signal LED having gone out. Prompted huddle tests.

Next Steps

  1. Alexei/Stephen - Finalize documentation from attached plots.  Calculate and compare Q's from fft spectra.

Photos/Figures

See attached

 

  138   Mon May 20 14:05:56 2019 Marie K.ProgressBS BRDsElectronics moved to the Modal Lab

[Rich, Marie]

Today we moved the shelves containing the electronics for the BOSEM control and acquisition from Thomas Lab to the Modal Lab. The shelves are now near the dummy BS. We are planning to measure the bounce and roll modes of the BS suspension with and without BRDs. Please find attached some pictures for visual reference.

Luis fixed the satellite box for us, thanks! It is now in the lab, we still have to incorporate it back in the setup.

 

Attachment 1: IMG_20190520_101605561.jpg
IMG_20190520_101605561.jpg
Attachment 2: IMG_20190520_101623717.jpg
IMG_20190520_101623717.jpg
Attachment 3: IMG_20190520_101745757.jpg
IMG_20190520_101745757.jpg
Attachment 4: IMG_20190520_102700780.jpg
IMG_20190520_102700780.jpg
Attachment 5: IMG_20190520_141445408_HDR.jpg
IMG_20190520_141445408_HDR.jpg
  139   Mon May 20 18:24:11 2019 Marie K. ProgressBS BRDsTest of the new springs

We received the 12 new springs made with a sandwich layer of Pyralux damping today (see dcc D1700188-v3). 

According to T1700176, the bounce and roll modes of the dummy BS in the modal lab are respectively 16.70 Hz and 24.34 Hz. Aiming for a Q~100 for the damped BS, the relative mass of the damper and the modes has to be > 2.0e-4. It means the masses have to be >= 5.556 g for the bounce mode and >= 2.580 g for the roll mode, taking into account the weight of the spring (0.168 g) and the screws (~0.49g each). I got: mb = 0.91 + 4.23 + screw = 5.622 g for bounce and mr = 2*1.06 + screw = 2.620 g for roll. 

Calum helped me taking the first measurement of the new BRD with the B&K software and the vibrometer. We found that the roll resonance is at 27.750 Hz (i.e. 14% too high), with a measured BRD Q of 59 (TBC).

Attachment 1: IMG_20190520_164859560.jpg
IMG_20190520_164859560.jpg
Attachment 2: IMG_20190520_184709517.jpg
IMG_20190520_184709517.jpg
  140   Tue May 21 16:37:06 2019 Marie K.ProgressBS BRDsFirst Q measurements

[Calum, Chub, Marie]

We installed a new support for the BOSEM (see first picture attached). The bosem translation stage seats on an aluminium plate, above a bridge in aluminium that is clamped to the BS cage.

Then we reconnected the satellite box in the setup, and we were able to restart the bosem excitation and the data acquisition. We removed the BRDs that had been previously installed on the pum. Then we measured the BS bounce and roll modes:

  • Excitation from the signal generator at 16.70 Hz. Resonance max is at 16.75 Hz. The measured Q is more than 4400 (see figure 2).
  • Excitation at 24.34 Hz. Resonance maximum is at 24.41 Hz. The measured Q is above 4300 (see figure 3).

We will scan around the resonances to check if the frequency is the sameas it was measured previously.

 

On the side, I measured the BRD that was assembled yesterday (brd_v4_n1) with the vibrometer:

  • The bounce frequency is 14.9 Hz, but the precision of the measurement is only 0.1 Hz (see for example figure 4). This is ~12% lower than expected. The mean value of 9 ringdown measurements indicate that the Q is about 85 +/- 3 (see an example figure 5).
  • The roll frequency is 27.9 Hz, with a precision of 0.1 Hz. This is ~ 14% higher than expected. The mean value of 5 ringdown measurements indicate that the Q is about 83 +/- 4. (see figure 6).

There is quite a large dispersion in the measurement of the Q, I have to improve (or pratice) the technique to excite only the main mode and avoid saturations (only 9 out of my 30 measurements are clean for bounce and 5 out of 30 for roll).

The Q's are lower than what had been measured with the version 3 of the blades, so we are probably going in the right direction (bounce mode Q ~ 135, roll mode Q~125 in T1700176-v7, section 6.2)

Attachment 1: Bosem_support.jpg
Bosem_support.jpg
Attachment 2: BS_bounce_ringdown.png
BS_bounce_ringdown.png
Attachment 3: BS_roll_ringdown.png
BS_roll_ringdown.png
Attachment 4: spectra_brdv4n1_bounce.png
spectra_brdv4n1_bounce.png
Attachment 5: ringdown_test6_Q90.png
ringdown_test6_Q90.png
Attachment 6: ringdown_roll_test4_Q80.png
ringdown_roll_test4_Q80.png
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