[Jeff, Yuta, Koji]

Gluing test with UV-cure epoxy Optocast 3553-LV-UTF-HM

- This glue was bought in the end of October (~3.5 months ago).

- The glue was taken out from the freezer at 1:20pm.
- Al sheet was laid on the optical table. We made a boat with Al foil and pour the glue in it (@1:57pm)
- We brought two kinds of Cu wires from the 40m. The thicker one has the diameter of 1.62mm.
The thinner one has the diameter of 0.62mm. We decided to use thinner one being cut into 50mm in length.

- The OMC glass prisms have the footprint of 10mmx20mm = 200mm^2. We tested several combinations
of the substrates. Pairs of mirrors with 1/2" mm in dia. (127mm) and a pair of mirrors with 20mm in dia. (314mm).

- Firstly, a pair of 1/2" mirrors made of SF2 glass was used. A small dub on a thinner Cu wire was deposited on a mirror.
  We illuminated the glue for ~10sec. When the surfaces of the pair was matched, the glue did not spread on the entire
  surface. The glue was entirely spread once the pressure is applied by a finger. Glue was cured at 2:15pm. 12.873mm
  thickness after the gluing.

Some remark:
1. We should be careful not to shine the glue pot by the UV illuminator.
2. The gluing surface should be drag wiped to remove dusts on the surface.

- Secondly, we moved onto 20mm mirror pair taken from the remnant of the previous gluing test by the eLIGO people.
This time about 1.5 times more glue was applied.

- The third trial is to insert small piece of alminum foil to form a wedge. The thickness of the foil is 0.041mm.
The glue was applied to the pair of SF2 mirror (1/2" in dia.). A small dub (~1mm in dia) of the glue was applied.
The glue filled the wedge without any bubble although the glue tried to slide out the foil piece from the wedge.
So the handling was a bit difficult. After the gluing we measured the thickness of the wedge by a micrometer gauge.
The skinny side was 12.837mm, and the thicker side was 12.885mm. This is to be compared with the total thickness
12.823mm before the gluing. The wedge angle is 3.8mrad (0.22deg). The glue dub was applied at 2:43, and the UV
illumination was applied at 2:46.

- At the end we glued a pair of fused silica mirrors. The total thickness before the gluing was 12.658 mm.
The glue was applied at 2:59pm. The thickness after the gluing is 12.663 mm.
This indicates the glue thickess is 5um.

[Koji Lisa Jeff Zach]

Eric G bought a UV power meter from American Ultraviolet.

Our UV illuminator was calibrated by this power meter.

The first blast (i.e. cold start): 3.9W/cm^2

After many blasting: 8.3W/cm^2

The spec is 20W/cm^2

TEST Result: S1500118

Additional notes

- Checked the power supply. All voltages look quiet and stationary.

- Checked the internal RF cables too see if there is any missing shield soldering => Looked fine

- Noticed that the RFAM detector board has +/-21V for the +/-24V lines => It seems that this is nominal according to the schematic

- Noticed that the RFAM detector sensitivity were doubled fomr the other unit.
  => This is reated to the modification (E1500353) of  "Controller Board D0900761-B Change 1" (doubling the monitor output gain)

- Noticed that the transfer function of the CTRL signal on the BNC and the DAQ output.
  => This is reated to the modification (E1500353) of  "Servo Board D0900847-B Change 1"  (servo transfer function chage)
  => The measured transfer function did not agree with the prediction from the circuit constants in this document
  => From the observation of the servo board it was found that R69 was not 200Ohm but 66.5 Ohm (See attachment 1).
       This explained the measured transfer function. The actuator TF has: P 2.36, Z 120., K -1@DC (0.020@HF)

- Similarly, the TF between the CTRL port on the unit and the CTRL port on the test rig was also modified.

Noise level

Attachment 2

- The amplitude noise in dBc (SSB) was measured at the output of 27dBm. From the test sheet, the noise level with 13dBm output was also referred. From the coherence of the MON1 and MON2, the noise level was inferred. It suggests that the floor level is better than 180dBc/Hz. However, there is a 1/f like noise below 1k and is dominating the actual noise level of the RF output. Daniel suggested that we should check nonlinear downconversion from the high frequency noise due to the noise attenuator. This will be check with the coming units.

Nicolas Smith,
LIGO Document T0900383-v1
3mm Photodiode Characterization for Enhanced LIGO
https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=4498

Tobin Fricke,
LIGO Document P1000010-v1
Homodyne detection for laser-interferometric gravitational wave detectors
https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=8443

Nicolas Smith,
LIGO Document P1200052-v1
Techniques for Improving the Readout Sensitivity of Gravitational Wave Antennae
https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=90498

Wedge angle test

Result: Wedge angle of Prism A1: 0.497 deg +/- 0.004 deg

Principle:

o Attach a rail on the optical table. This is the reference of the beam.

o A CCD camera (Wincam D) is used for reading out spot positions along the rail.

o Align a beam path along the rail using the CCD.

o Measure the residual slope of the beam path. (Measurement A)

o Insert an optic under the test. Direct the first surface retroreflectively. (This means the first surface should be the HR side.)

o Measure the slope of the transmitted beam. (Measurement B)

o Deflection angle is derived from the difference between these two measurements.

Setup:

o An Al plate of 10" width was clamped on the table. Four other clamps are located along the rail to make the CCD positions reproducible.

o A prism (Coating A, SN: A1) is mounted on a prism mount. The first surface is aligned so that the reflected beam matches with the incident beam
with precision of +/-1mm at 1660mm away from the prism surface. ==> precision of +/- 0.6mrad

o In fact, the deflection angle of the transmission is not very sensitive to the alignment of the prism.
The effect of the misalignment on the measurement is negligible.

o Refractive index of Corning 7980 at 1064nm is 1.4496

Result:

Without Prism
Z (inch / mm), X (horiz [um] +/-4.7um), Y (vert [um] +/-4.7um)
0” / 0, -481.3, -165.1
1.375" / 34.925, -474.3, -162.8
3" / 76.2, -451.0, -186.0
4.375" / 111.125, -432.5, -181.4
6" / 152.4, -432.5, -181.4
7.375" / 187.325, -330.2, -204.6
9" / 228.6, -376.7, -209.3

With Prism / SN of the optic: A1
Z (inch / mm), X (horiz [um] +/-4.7um), Y (vert [um] +/-4.7um)
0” / 0, -658.3, -156.8
1.375" / 34.925, -744.0, -158.1
3" / 76.2, -930.0, -187.4
4.375" / 111.125, -962.6, -181.4
6" / 152.4, -1190.4, -218.6
7.375" / 187.325, -1250.9, -232.5
9" / 228.6, -1418.3, -232.5

Analysis:

Wedge angle of Prism A1: 0.497 deg +/- 0.004 deg

[Click for a sharper image]

The wedge angle of the prism "A1" was measured with the autocollimator (AC).

The range of the AC is 40 arcmin. This means that the mirror tilt of 40arcmin can be measured with this AC.
This is just barely enough to detect the front side reflection and the back side reflection.

The measured wedge angle of the A1 prism was 0.478 deg.

Ideally a null measurement should be done with a rotation stage.

Method:

• Mount the tombstone prism on the prism mount. The mount is fixed on the rotation stage.
• Locate the prism in front of the autocollimator.
• Find the retroreflected reticle in the view. Adjust the focus if necessary.
• Confirm that the rotation of the stage does not change the height of the reticle in the view. 

  If it does, rotate the AC around its axis to realize it.
  This is to match the horizontal reticle to the rotation plane.
• Use the rotation stage and the alignment knobs to find the reticle at the center of the AC.
Make sure the reticle corresponds to the front surface.
• Record the micrometer reading.
• Rotate the micrometer of the rotation stage until the retroreflected reticle for the back surface.
• There maybe the vertical shift of the reticle due to the vertical wedging. Record the vertical shi
• Record the micrometer reading. Take a difference from the previous value.
   

Measurement:

• A1: α = 0.68 deg, β = 0 arcmin (0 div)
• A2: α = 0.80 deg, β = -6 arcmin (3 div down)
• A3: α = 0.635 deg, β = -1.6 arcmin (0.8 div down)
• A4: α = 0.650 deg, β = 0 arcmin (0div)
• A5: α = 0.655 deg, β = +2.4 arcmin (1.2 div up)

Analysis:

• \theta_H = ArcSin[Sin(α) / n]
• \theta_V = ArcSin[Sin(β) / n]/2
   
• A1: \theta_H = 0.465 deg, \theta_V = 0.000 deg
• A2: \theta_H = 0.547 deg, \theta_V = -0.034 deg
• A3: \theta_H = 0.434 deg, \theta_V = -0.009 deg
• A4: \theta_H = 0.445 deg, \theta_V = 0.000 deg
• A5: \theta_H = 0.448 deg, \theta_V = 0.014 deg

Measurement:

• A6:   α = 0.665 deg, β = +3.0 arcmin (1.5 div up)
• A7:   α = 0.635 deg, β =   0.0 arcmin (0.0 div up)
• A8:   α = 0.623 deg, β = - 0.4 arcmin (-0.2 div up)
• A9:   α = 0.670 deg, β = +2.4 arcmin (1.2 div up)
• A10: α = 0.605 deg, β = +0.4 arcmin (0.2 div up)
• A11: α = 0.640 deg, β = +0.8 arcmin (0.4 div up)
• A12: α = 0.625 deg, β = - 0.6 arcmin (-0.3 div up)
• A13: α = 0.630 deg, β = +2.2 arcmin (1.1 div up)
• A14: α = 0.678 deg, β =   0.0 arcmin (0.0 div up)
• B1:   α = 0.665 deg, β = +0.6 arcmin (0.3 div up)
• B2:   α = 0.615 deg, β = +0.2 arcmin (0.1 div up)
• B3:   α = 0.620 deg, β = +0.9 arcmin (0.45 div up)
• B4:   α = 0.595 deg, β = +2.4 arcmin (1.2 div up)
• B5:   α = 0.635 deg, β = - 1.8 arcmin (-0.9 div up)
• B6:   α = 0.640 deg, β = +1.6 arcmin (0.8 div up)
• B7:   α = 0.655 deg, β = +2.5 arcmin (1.25 div up)
• B8:   α = 0.630 deg, β = +2.8 arcmin (1.4 div up)
• B9:   α = 0.620 deg, β = - 4.0 arcmin (-2.0 div up)
• B10: α = 0.620 deg, β = +1.2 arcmin (0.6 div up)
• B11: α = 0.675 deg, β = +3.5 arcmin (1.75 div up)
• B12: α = 0.640 deg, β = +0.2 arcmin (0.1 div up)

Analysis:

• \theta_H = ArcSin[Sin(α) * n]
• \theta_V = ArcSin[Sin(β) / n]/2
   
• A6:   \theta_H = 0.490 deg, \theta_V =  0.017 deg
• A7:   \theta_H = 0.534 deg, \theta_V =  0.000 deg
• A8:   \theta_H = 0.551 deg, \theta_V = -0.0023 deg
• A9:   \theta_H = 0.482 deg, \theta_V =  0.014 deg
• A10: \theta_H = 0.577 deg, \theta_V =  0.0023 deg
• A11: \theta_H = 0.526 deg, \theta_V =  0.0046 deg
• A12: \theta_H = 0.548 deg, \theta_V = -0.0034 deg
• A13: \theta_H = 0.541 deg, \theta_V =  0.013 deg
• A14: \theta_H = 0.471 deg, \theta_V =  0.000 deg
• B1:   \theta_H = 0.490 deg, \theta_V =  0.0034 deg
• B2:   \theta_H = 0.563 deg, \theta_V =  0.0011 deg
• B3:   \theta_H = 0.556 deg, \theta_V =  0.0051 deg
• B4:   \theta_H = 0.592 deg, \theta_V =  0.014 deg
• B5:   \theta_H = 0.534 deg, \theta_V = -0.010 deg
• B6:   \theta_H = 0.526 deg, \theta_V =  0.0091 deg
• B7:   \theta_H = 0.504 deg, \theta_V =  0.014 deg
• B8:   \theta_H = 0.541 deg, \theta_V =  0.016 deg
• B9:   \theta_H = 0.556 deg, \theta_V = -0.023 deg
• B10: \theta_H = 0.556 deg, \theta_V =  0.0068 deg
• B11: \theta_H = 0.475 deg, \theta_V =  0.020 deg
• B12: \theta_H = 0.526 deg, \theta_V =  0.0011 deg

Measurement:

• E1:   α = 0.672 deg, β = +0.0 arcmin (0 div up)
• E2:   α = 0.631 deg, β = - 0.3 arcmin (-0.15 div down)
• E3:   α = 0.642 deg, β = +0.0 arcmin (0 div up)
• E4:   α = 0.659 deg, β = +1.4 arcmin (0.7 div up)
• E5:   α = 0.695 deg, β = +0.5 arcmin (0.5 div up)
• E6:   α = 0.665 deg, β = - 0.4 arcmin (-0.2 div down)
• E7:   α = 0.652 deg, β = +1.0 arcmin (0.5 div up)
• E8:   α = 0.675 deg, β = +2.0 arcmin (1.0 div up)
• E9:   α = 0.645 deg, β = - 2.4 arcmin (-1.2 div down)
• E10: α = 0.640 deg, β = +2.2 arcmin (1.1 div up)
• E11: α = 0.638 deg, β = +1.6 arcmin (0.8 div up)
• E12: α = 0.660 deg, β = +1.6 arcmin (0.8 div up)
• E13: α = 0.638 deg, β = +0.8 arcmin (0.4 div up)
• E14: α = 0.655 deg, β = +0.4 arcmin (0.2 div up)
• E15: α = 0.640 deg, β = +1.4 arcmin (0.7 div up)
• E16: α = 0.655 deg, β = +0.6 arcmin (0.3 div up)
• E17: α = 0.650 deg, β = +0.8 arcmin (0.4 div up)
• E18: α = 0.640 deg, β = +2.4 arcmin (1.2 div up)

Analysis:

• \theta_H = ArcSin[Sin(α) / n]
• \theta_V = ArcSin[Sin(β) / n]/2
   
• E1:   \theta_H = 0.460 deg, \theta_V =   0.000 deg
• E2:   \theta_H = 0.432 deg, \theta_V =  -0.0034 deg
• E3:   \theta_H = 0.439 deg, \theta_V =   0.000 deg
• E4:   \theta_H = 0.451 deg, \theta_V =  0.016 deg
• E5:   \theta_H = 0.475 deg, \theta_V =  0.011 deg
• E6:   \theta_H = 0.455 deg, \theta_V =  -0.0046 deg
• E7:   \theta_H = 0.446 deg, \theta_V =  0.011 deg
• E8:   \theta_H = 0.462 deg, \theta_V =  0.023 deg
• E9:   \theta_H = 0.441 deg, \theta_V =  -0.027 deg
• E10:   \theta_H = 0.438 deg, \theta_V = 0.025 deg
• E11:   \theta_H = 0.436 deg, \theta_V = 0.018 deg
• E12:   \theta_H = 0.451 deg, \theta_V = 0.018 deg
• E13:   \theta_H = 0.436 deg, \theta_V = 0.0091 deg
• E14:   \theta_H = 0.448 deg, \theta_V = 0.0046 deg
• E15:   \theta_H = 0.438 deg, \theta_V = 0.016 deg
• E16:   \theta_H = 0.448 deg, \theta_V = 0.0068 deg
• E17:   \theta_H = 0.444 deg, \theta_V = 0.0091 deg
• E18:   \theta_H = 0.438 deg, \theta_V = 0.027 deg

Yesterday I measured the thickness of the PZTs in order to get an idea how much the PZTs are wedged.

For each PZT, the thickness at six points along the ring was measured with a micrometer gauge.
The orientation of the PZT was recognized by the wire direction and a black marking to indicate the polarity.

A least square fitting of these six points determines the most likely PZT plane.
Note that the measured numbers are assumed to be the thickness at the inner rim of the ring
as the micrometer can only measure the maximum thickness of a region and the inner rim has the largest effect on the wedge angle.
The inner diameter of the ring is 9mm.



The measurements show all PZTs have thickness variation of 3um maximum.

The estimated wedge angles are distributed from 8 to 26 arcsec. The directions of the wedges seem to be random
(i.e. not associated with the wires)



As wedging of 30 arcsec causes at most ~0.3mm spot shift of the cavity (easy to remember),
the wedging of the PZTs is not critical by itself. Also, this number can be reduced by choosing the PZT orientations
based on the estimated wedge directions --- as long as we can believe the measurements.



Next step is to locate the minima of each curved mirror. Do you have any idea how to measure them?

Using the measurements of PZTs 12,13 taken by Stephen, I estimated the wedging angle and orientation following Section 2.3.1 of T1500060. The results can be found in Attachment1 and is summarised as follows.

For PZT 12, PZT 13 respectively:

Avg. height = 2.0063 mm, 2.0035 mm

Wedge direction (from the same direction as in the doc: positive right) = 120 deg, 120 deg

Wedge angles = 45.8 arcsec, 30.6 arcsec

This was done assuming that the measurements were taken uniformly at intervals of 60deg along the inner rim of the PZT. The diameter (2r) of the inner rim, according to T1500060, is 9mm. The measured heights were fitted with the function

as depicted in Attachment2 to find wedging angle and orientation .

Wedge and thickness measurements of PZTs 12 and 13 took place after debonding and cleaning - results are shown in the first image (handwritten post-it format).

These thickness measurements seem to have come back thinner than previous measurements. It is possible that I have removed some PZT material while mechanically removing glue. It is also possible that there is systematic error between the two sets of measurements. I did not run any calculations of wedge ange or orientation on these data.

Note that cleaning of debonded PZTs involved mechanically separating glue from the planar faces of PZTs. The second image shows the razer blade used to scrape the glue away.

There were thick rings of glue where there had been excess squeezed out of the bond region, and there was also a difficult-to-remove bond layer that was thinner. I observed the presence of the thin layer by its reflectivity. The thick glue came off in patches, while the thin glue came off with a bit of a powdery appearance. It was hard to be certain that all of the thin bond layer came off, but I made many passes on each of the faces of the 2 PZTs that had been in the bonded CM assemblies. I found it was easiest to remove the glue in the bonded

I was anticipating that the expected 75-90 micron bond layer would affect the micrometer thickness measurements if it was still present, but I did not notice any irregularities (and certainly not at the 10 micron level), indicating that the glue was removed successfully (at least to the ~1 micron level).

Suddenly something dirty emerged in the lab. What is this? It looks like an insulation foam or similar, but is quite degraded and emits a lot of particulates.

This does not belong to the lab. I don't see piping above this area which shows broken insulation or anything. All the pipes in the room are painted white.

The only possibility is that it comes from the hole between the next lab (CRIME Lab). I found that the A.C. today is much stronger and colder than last week. And there is a positive pressure from CRIME Lab. Maybe the foam was pushed out from the hole due to the differential pressure (or any RF cable action).

The Windows laptop for WincamD/Beam'R2 (DELL Vostro3300) was not functional.
- Windows 7 got stuck in the starting up process (Google "startup repair loop")
- The battery can't charge and the adapter connection is flaky

I decided to newly install Win10.
I made a new bootable Win10 DVD from the ISO downloaded from IMSS. The ISO file was converted to CDR using Disk Utility on Mac.
This deleted the past disk partitions. The installation process has no trouble and Win10 ran successfully. The machine is slow but still acceptable for our purpose.
Dataray Version 7.1H25Bk was downloaded from the vendor website https://dataray.com/blogs/software/downloads and installed successfully.
The devices ran as expected by connecting the heads and selecting the proper device in the software.

Then, the Win10 fell into "Hibernation Loop" and "Shutdown loop" (after disabling hibernation in the safe mode).
This is probably the combination of extremely slow windows update (feature update i.e. beta OS update) and the occasional shutdown due to the flakiness of the AC connection

Win10 was reinstalled and automatic Win update was disabled via windows policy manager or something like that. Still, it tries to download and update some of the updates (what's happening there!?

Here are my strong recommendations on how to use this laptop

• Do not use any network connection. It will enable Windows Update kicks in and destroy the machine.
• Use a USB stick for data transportation if necessary
• The laptop should always be connected to the power supply at a stable location. (The adapter connection is flaky and the battery is dead)
• Buy a replacement battery (maybe a 3rd-party cheap one
• The Win10 DVD should always be inserted into the laptop's drive so that we can reinstall the windows anytime.

Aaron took the set to Cryo lab

• Work done
  • Floor cleaning [ELOG]
  • Placing sticky mats [ELOG]
  • Label Maker purchased
  • Ordered a lab desk at the west side of the room
    http://www.globalindustrial.com/p/work-benches/systems/adjustable-height/72-l-x-36-w-production-bench-esd-square-edge-blue-2
  • Ordered clean / ESD  stools (~25" height)
    http://www.globalindustrial.com/p/office/stools/vinyl/esd-safe-vinyl-clean-room-stool-with-nylon-base-with-drag-chain-blue
  • Asked Gina for the electronics rack
    www.racksolutions.com/server-racks-cabinets-enclosures.html
    36U Height / 20" depth + Caster kit
  • 5 shelves ordered from AlliedElectronics (Quest technology ES0319-0115, 19"x15" non-vented shelf)
    http://www.racksolutions.com/rack-shelves
  • Plug slits on the roof of the HEPA booth (Peter)
  • Laser safety barrier (Peter) [ELOG]
  • Workbenches and clean room stools [ELOG]
  • OMC Mirros have been delivered (~Oct 10)
  • Halogen light source has been delivered
  • UV light guide has been delivered
     
• Things ordered
  
  • Office Depot
    • [delivered] Office Depot(R) Brand Stretch Wrap Film, 20 x 1000 Roll, Clear / 445013
    • [delivered] Eveready(R) Gold AA Alkaline Batteries, Pack Of 24 / 158448
    • [delivered] Rubbermaid(R) Roller Sponge Mop / 921841
    • [delivered] Rubbermaid(R) Roller Sponge Mop Replacement / 921858
    • [delivered] Rubbermaid(R) Sanitizing Caddy, 10 Quarts, Yellow / 674125
    • [delivered] Glad(R) Tall Kitchen Trash Bags, 13 Gallon, White, Box Of 28 / 269268
  • Global Industrial Equipment
    
    • [delivered] Extended Surface Pleated Cartridge Filter Serva-Cell Mp4 Slmp295 12X24X2 Gl    WBB431699
  • Global Industrial Equipment
    
    • [delivered] Nexel Poly-Z-Brite Wire Shelving 30"W x 21"D x 63"H Nexel Poly-Z-Brite™ Wire Shelving Starter Unit WB189209
    • [delivered] Stem Casters Set of (4) 5" Polyurethane Wheel, 2 With Brakes 1200 lb. Capacity WB500592    
  • Rack Solutions
    • [delivered] Open Frame Server Racks
      1 x 20" Depth Kit (Ideal for Audio/Video or Networking Racks) P/N: 111-1779
      1 x 36U, Rack-111 Post Kit P/N: 111-1728
      1 x Caster Kit for Open Frame RACK-111 P/N: 111-1731
    • [delivered] 36U Side Panel Kit $199.99 P/N: 102-1775
  • Rack shelf
    • [delivered] 1 RMS 19 X 15 SINGLE SIDED NON-VENTED SHELF 70121637
  • Work bench, Stools
    • [not yet] 72"L X 30"W Production Bench - Phenolic Resin Square Edge-Blue Form attached WB237381LBL    
    • [not yet] 72"W Lower Shelf For Bench - 15"D- Blue Form attached WB606951    
    • [not yet] ESD-Safe Vinyl Clean Room Stool with Nylon Base with Drag Chain Blue Form attached WBB560852    
  • P Touch
    • [delivered] Brother PT-2030 Desktop Office Labeler Punch-out product 672828    
    • [delivered] Brother(R) TZe-241 Black-On-White Tape, 0.75 x 26.2 Punch-out product 239384    
    • [delivered] Brother(R) TZe-231 Black-On-White Tape, 0.5 x 26.2 Punch-out product 239400    
      
  • UV light guide
    • [delivered] Fiber Optic Single Light Guide 5mm OD X 3mm ID X 1M L Note: This light guide can be used with MKIII UV Cure unit. OLB1081
  • Gloves (7.5, 8.0)
    • [delivered] GLOVE ACCTCH NR-LTX SZ7.5 PK25 Punch-out product 79999-306
    • [delivered] GLOVE ACCTCH NR-LTX SZ8 PK25 Punch-out product 79999-308
  • Lab coat (L,XL), Sticky Mat, Shoe Covers (L, XL), Cap, Mask
    • [delivered] LAB XP WH EL WR.COLL. NP L30EA Punch-out product 82007-618
    • [delivered] LAB XPWH EL WR.COLL. NP XL30EA Punch-out product 82007-620    
    • [delivered] VWR MAT ADHESIVE 30L 18X36 BLU Punch-out product 21924-110 (This was too small)
    • [delivered] VWR SHOECVR NSKID AP 2XL 150PR Punch-out product 414004-651    
    • [delivered] VWR SHOECVR NSKID AP XL 150PR Punch-out product 414004-650    
    • [delivered] CAP BOUFFANT 24IN RAYON CS500 Punch-out product 10843-053    
    • [delivered] MASK VLTC TIES N/STRL PK50 Punch-out product 10869-020
      
  • VWR
    • [delivered] FACE SHIELD UVC-803 Supplier: UVP 33007-151
       
  • [Delivered] Laser safety glasses
    
    • 35-200 Laser Glasses (PN 100-35-200) Qty.2 Price 189.00 ea
      http://www.lasersafetyindustries.com/35_200_Laser_Safety_Glasses_p/35-200.htm
    • Black Sport-wrap Laser Glasses 950-3600 nm (PN 100-38-200) Qty.1 Price 169.00 ea
      http://www.lasersafetyindustries.com/Black_Sport_wrap_Glasses_Diode_Nd_YAG_Er_YAG_p/100-38-200.htm

• Completed Work: Facility/Supplies
  • Plug a big hole on the wall [ELOG]
  • Purchasing work benches
    
    • W60" x H28-34" x D30" http://www.globalindustrial.com/p/work-benches/systems/adjustable-height/60x30-esd-square-edge-power-apron-production-bench-blue
    • Lower shelf W60" http://www.globalindustrial.com/p/work-benches/systems/adjustable-height/60-w-lower-shelf-bench-15-d-blue
  • Wooden work benches removed(arranging the work with Louisa)
     
  • Al foils (All foils inc, should get a certificate everytime to ensure UHV compatibility)
  • Laser / UV safety glass/face mask (Ordered with Gina, UV face shield ordered through Techmart)
    • 35-200 Laser Glasses (PN 100-35-200) Qty.2 Price 189.00 ea
      http://www.lasersafetyindustries.com/35_200_Laser_Safety_Glasses_p/35-200.htm
    • Black Sport-wrap Laser Glasses 950-3600 nm (PN 100-38-200) Qty.1 Price 169.00 ea
      http://www.lasersafetyindustries.com/Black_Sport_wrap_Glasses_Diode_Nd_YAG_Er_YAG_p/100-38-200.htm
    • VWR has FACE SHIELD UVC-803 and this is ANSI-Z87.1 1986 compliant and the O.D. is more than 5.
      https://us.vwr.com/store/catalog/product.jsp?catalog_number=33007-151
  • Sticky mat
    
    • VWR MAT ADHESIVE 30L 18X36 BLU, 21924-110
  • Shoe cover
    • VWR SHOECVR NSKID AP XL 150PR, 414004-650
    • VWR SHOECVR NSKID AP 2XL 150PR, 414004-651
  • Lab coat
    
    • VWR Lab coat L 82007-618 / XL 82007-620
  • Hat
    
    • VWR Hat 10843-053
  • Mask
    
    • VWR Face Masks 10869-020
  • Gloves
    
    • VWR GLOVE ACCTCH NR-LTX SZ7.5 PK25 79999-306 x4
    • VWR GLOVE ACCTCH NR-LTX SZ8 PK25 79999-308 x4
  • Plastic boxes for storage
    http://www.drillspot.com/products/422140/Rubbermaid_2282-00-CLR_18GAL_Clear_Snap_Case
    (We have 12 for now. More stored at the 40m)
     
• Completed Work: Optics
  • UV Lamp arrived (shipped from LLO)
    
  • Fiber light guide for UV lamp (Quote obtained / Ordered via techmart)
  • Optical test planning by Zach [ELOG]
  • How to handle First Contact by Margot [ELOG]
  • Useful links / OMC scanning [ELOG]

Completed work of the previous months: [Jul] [Aug] [Sep] [Oct] [Nov] [Dec]

• Work done
  • Wedge measurement (1st trial) [ELOG]
  • RoC measurement [ELOG]
  • Laser SOP draft

• Things delivered
  • The ionized gun used in the clean room at Downs: made by Terra Universal.com (Jeff's room)
    http://www.terrauniversal.com/static-control/ionizing-blow-off-guns.php
  • Flow path: N2 cylinder - Filter - Gun (Jeff's room)
  • Power strips Tripp Lite PS3612 (Ordered Nov. 8, Delivered Nov. 12)
  • Kapton tapes (1in x 6, 1/2in x 12 Delivered Nov. 15)
  • Sticky Mats (VWR 18888-216 Delivered Nov. 12 and 21992-042)
  • Duck tape (PK3) (Delivered Nov. 12)
  • Wipers 12"x12" 2ply x 119 pairs x case15 (Delivered Nov. 12)
  • Syringes (1mL&2mL) & Needles (20G x dozen)
  • Stainless trays with cover (Steve Delivered Nov. 12)
  • Gold Plated allen keys (Steve Delivered Nov. 12)
  • Forceps (Delivered Nov. 12) / Tweezers / Scissors (Delivered Nov. 12)
  • OMC testing optics / opto-mechanics
  • SolidWorks raytracing model
  • Mode design for HAM6 layout [Zach]
     
  • Black Glass / Black Glass holder / AR ==> Some at the 40m, some from LLO
  • Ionized air blow
    • N2 or Air cylinder: 4N - UHP or 5N - Research Grade.  (... steal from Downs)

Completed work of the previous months: [Jul] [Aug] [Sep] [Oct] [Nov] [Dec]

• Work done
  • Particle Level measured / HEPA activated [ELOG]
  • Particle counter peripherals arrived ~Oct 12.
  • Making the OMC optical test setup [ELOG] [ELOG] [ELOG] [ELOG] [ELOG]
  • OMC Bread board dimensions / weights measurement by Jeff and Jam [ELOG]
  • UV epoxy has arrived - stored in a freezer in the office
    • UV cured epoxy (Quote obtained)
      
    • Electronic Materials Inc.'s Optocast 3553LV-UTF-HM
      (A Low Viscosity, Ultra Thin Film epoxy with Heat Mechanism. The assembly/cure procedure includes both a UV binding step and a 120 degree cure for 24 hours.)
    • Ref1: Dennis Coyne, LIGO-E960050-v11,
      https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=3879
    • Ref2: Tobin Fricke, LIGO Document P1000010-v1, Homodyne detection for laser-interferometric gravitational wave detectors
      https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=8443
    • Ref3: OMC Construction Wiki https://awiki.ligo-wa.caltech.edu/aLIGO/OMC_Construction
    • The glue should be stored at T<0degC ==> Freezer in a lab
  • Laser sign installed during my trip by Peter/Eric
  • OMC design downselect [DCC Link]

Koji, Rich

We took apart the unit removed from the 3rd IFO (Unit serial number aLIGO #3, XTAL 10252004) to see what makes it tick.  Koji has done a fine job of adding the plots of the impedance data to this log book.  Attached are some details of the physical construction showing the capacitor values used in shunt before the coils.

Last Friday, new workbenches were installed. Vladimir got a new table and a cleanroom stool.

The other two workbenches were also nicely set.

[Camille, Thejas, Stephen]

We modified the Zygo setup for measuring the sagitta of the curved mirrors. A mirror at 45deg was used to reflect the interferometer beam down towards the surface of the table (see picture). A fused silica flat was placed horizontally with the surface of the table and was used as our reference flat. The back surface of the curved mirror and the top surface of the reference flat were cleaned using top gun and/or swabs. Once it was verified that the surfaces were clean, the curved mirror could be easily placed on the surface of the reference flat.

Once the curved mirror was placed on the reference flat, the fringes of the reference flat were nulled using the 45deg mirror. After nulling the flat's fringes, the data was recorded. The curved mirror was then rotated 90deg clockwise. The measurment was repeated with the curved mirror's fiducial located at 12:00, 3:00, 6:00 and 9:00. The 12:00 position was measured twice to ensure repeatability. (A drop of first contact had been placed at the edge of the optic to indicate where the fiducial arrow is. This helped with clocking alignment.)

The already-characterized aLIGO C7 mirror was measured to verify the setup. After verifying agreement with the results in T1500060, this process was repeated with all the remaining curved mirrors.

The data was analyzed using Thejas's python script (separation distance between mirror center and curvature minimum, angular position of curvature minimum.) Those mirrors with a large spread in the measurements will be remeasured.

https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=7410

Weights:

Suspension cage and transportation box: 250.8lb
Suspension cage and transportation box: 150.2lb ==> 100.6lb ==> 45,630 g

Metal Breadboard: 7261 g

Glass Breadboard and transportation fixture: 16382 g
Transportation fixture only: 9432 g ==> 6950 g
Added mass (up to now): 300 g ==> 7250 g

Preamp arrangement

https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=7373

[Koji Zach]

We worked on the OMC test over the weekend.

- At the beginning, the measured OMC transmission was ~85% even after subtracting the junk light and sidebands from the calculation.

- A pretty visible (by eye) dust were on CM1. Also a small residue of First Contact was found on the same mirror.

- We applied FC only on CM1 to remove these.

- The measued transmission went up to the level of 96%.

- We swept the incident power from 0.3mW to 30mW in order to see the dependence of the transmission against the incident power.

- The variation of the transmission ~10% was observed (attached figure 1, Red). This was compared with the similar dependence measured at Caltech (Magenta)

- So, the reduction of the transmission was observed as in eLIGO, although the measurements at Caltech and LLO are not consistent.

- Can this be attributed to the dependence of the PD efficiency? We measured the incident power on the PDs together with the preamp DC output. (Figure.2)
  This gives us how the responsivity changes with the incident power.

- Nevertheless, the dependence remains. We'll make more accurate measurement today.

https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=7395

[Koji Zach Suresh]

The OMC arrived at LLO without any destruction!

• We found that one shock sensor on the box turned red, the other stayed white.
• We brought the Perican case to the changing room and the wrapping was opened in the optics lab.
• The OMC was discovered without any obvious damage. Successful shipment!
• The inspection with a halogen light indicated some amount of particules on the breadboard.
  The both sides of the breadboard were wiped with the cleanroom cloth.
• The First Contact layers on the optics were removed while the ionized nitrogen gas was brew.

OMC installed in HAM6!
https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=7486

 For various reasons, I had to switch NPROs (from the LightWave 126 to the Innolight Prometheus).

I installed the laser, realigned the polarization and modulation optics, and then began launching the beam into the fiber, though I have not coupled any light yet.

A diagram is below. Since I do not yet have the AOM, I have shown that future path with a dotted line. Since we will not need to make AMTFs and have a subcarrier at the same time, I have chosen to overload the function of the PBS using the HWP after the AEOM. We will operate in one of two modes:

1. AMTF mode: The AOM path is used as a beam dump for the amplitude modulation setup. A razor dump should physically be placed somewhere in the AOM path.
2. Subcarrier mode: The AEOM is turned off and the HWP after it is used to adjust the carrier/subcarrier power ratio. I chose a 70T / 30R beamsplitter for the recombining, since we want to be able to provide ~100 mW with the carrier for transmission testing, and we don't need a particularly strong subcarrier beam for probing.

One thing that concerns me slightly: the Prometheus is a dual-output (1064nm/532nm) laser, with separate ports for each. I have blocked and locked out the green path physically, but there is some residual green light visible in the IR output. Since we are planning to do the OMC transmission testing with a Si-based Thorlabs power meter---which is more sensitive to green than IR---I am somewhat worried about the ensuing systematics. I *think* we can minimize the effect by detuning the doubling crystal temperature, but this remains to be verified.

 EDIT (ZK): Valera says there should be a dichroic beam splitter in the lab that I can borrow. This should be enough to selectively suppress the green.

[Jeff Koji]

The breadboard (SN2) was loaded on the transportation fixture.

The laser side template was installed and the cavity mirrors were placed.

The laser beam will be resonated in the cavity next week.

POSTED to 40m ELOG

2nd optical test http://nodus.ligo.caltech.edu:8080/40m/13725

[Thejas, Camille, Koji]

We aligned the laser beam to the cavity and drove the OMC cavity PZTs (0 to 5 V from signal generator with 15x amp from the piezo driver) with a ramp signal and logged the transmission mode spectrum. The drive PZT voltage changes from 3.4 V to 7 V for one fringe shift or half wavelength change in cavity length. The voltage gain of the PZT driver is 15 V/V so that's a difference of 54 V for half weavelngth of driving or 532 nm/54V or 9.85 nm/V. 

[Camille, Koji, Thejas]

Yesterday, we cleaned the cavity optics with first contact, aligned the input laser beam to the cavity and measured the power at different terminals on the cavity breadboard. 

The measured OMC losses were:
SET1 0.042 +/- 0.003
SET2 0.035 +/- 0.002
SET3 0.030 +/- 0.0014
-> 0.033 +/- 0.001

The measured OMC mode-matching efficiencies were:
SET1 0.9795 +/- 0.00016
SET2 0.9797 +/- 0.00005
SET3 0.9794 +/- 0.00035

Attached herewith is the scrrenshot of the notes of with input power parameters.

Monday, November 14, 2022

Camille and Koji did a "deep cleaning" of OMC#1:
1) Applied First Contact to the mirror surfaces. Removed first contact after ~10 minutes.
2) Acetone scrub of the mirror surfaces with a cotton swab.
3) Applied First Contact again. Removed after ~10 minutes. We left the FC paint on for the work on Thu.

The foggy spot on the input mirror was unchanged after the first round of First Contact. But the foggy spot came off during the acetone scrub.

EDIT (ZK): Koji points out that (1 - Ti) should really be the non-resonant reflectivity of the aligned cavity, which is much closer to 1. However, it should *actually* be the non-resonant reflectivity of the entire OMC assembly, including the steering mirror (see bottom of post). The steering mirror has T ~ 0.3%, so the true results are somewhere between my numbers and those with (1 - Ti) -> 1. In practice, though, these effects are swamped by the other errors.

More information about the power-dependent visibility measurement:

As a blanket statement, this measurement was done by exact analogy to those made by Sam and Sheon during S6 (c.f. LHO iLog 11/7/2011 and technical note T1100562), since it was supposed to be a verification that this effect still remains. There are absolutely better ways to do (i.e., ways that should give lower measurement error), and these should be investigated for our characterization. Obviously, I volunteer.

All measurements were made by reading the output voltages produced by photodetectors at the REFL and TRANS ports. The REFL PD is a BBPD (DC output), and the TRANS is a PDA255. Both these PDs were calibrated using a Thorlabs power meter (Controller: PM100D; Head: S12XC series photodiode-based---not sure if X = 0,2... Si or Ge) at the lowest and highest power settings, and these results agreed to the few-percent level. This can be a major source of error.

The power was adjusted using the HWP/PBS combination towards the beginning of the experiment. For reference, an early layout of the test setup can be seen in LLO:5978 (though, as mentioned above, the REFL and TRANS PDs have been replaced since then---see LLO:5994). This may or may not be a "clean" way to change the power, but the analysis should take the effect of junk light into account.

Below is an explanation of the three traces in the plot. First:

• TRANS: TRANS signal calibrated to W
• REFL_UL: REFL signal while cavity is unlocked, calibrated to W
• REFL_L: REFL signal while cavity is locked, calibrated to W
• Psb: Sideband power (relative to carrier)
• Ti: Input mirror transmission (in power)

Now, the traces

1. Raw transmission: This measurement is simple. It is just the raw throughput of the cavity, corrected for the power in the sidebands which should not get through. I had the "AM_REF" PD, which could serve as an input power monitor, but I thought it was better to just use REFL_UL as the input power monitor and not introduce the error of another PD. This means I must also correct for the reduction in the apparent input power as measured at the REFL PD due to the finite transmission of the input coupler. This was not reported by Sam and Sheon, but can be directly inferred from their data.
   • trans_raw = TRANS ./ ( REFL_UL * (1 - Psb) * (1 - Ti) )
   • Equivalently, trans_raw = (transmitted power) ./ (input power in carrier mode)
2. Coupling: This is how much of the power incident on the cavity gets coupled into the cavity (whether it ends up in transmission or at a loss port). Sheon plots something like (1 - coupling) in his reply to the above-linked iLog post on 11/8/2011.
   • coupling = ( REFL_UL * (1 - Ti) - REFL_L ) ./ ( REFL_UL * (1 - Psb) * (1 - Ti) )
   • Equivalently, coupling = [ (total input power) - (total reflected power on resonance) ] ./ (input power in carrier mode)
3. Visibility: How much of the light that is coupled into the cavity is emerging from the transmitted port? This is what Sam and Sheon call "throughput" or "transmission" and is what is reported in the majority of their plots.
   • visibility = TRANS ./ ( REFL_UL * (1 - Ti) - REFL_L )
   • Equivalently, visibility = (transmitted power) ./ [ (total input power) - (total reflected power on resonance) ]
   • Also equivalently, visibility = trans_raw ./ coupling

The error bars in the measurement were dominated, roughly equally, by 1) systematic error from calibration of the PDs with the power meter, and 2) error from noise in the REFL_L measurement (since the absolute AC noise level in TRANS and REFL_L is the same, and TRANS >> REFL_L, the SNR of the latter is worse).

(1) can be helped by making ALL measurements with a single device. I recommend using something precise and portable like the power meter to make measurements at all the necessary ports. For REFL_L/UL, we can place a beam splitter before the REFL PD, and---after calibrating for the T of this splitter very well using the same power meter---both states can be measured at this port.

(2) can probably be helped by taking longer averaging, though at some point we run into the stability of the power setting itself. Something like 30-60s should be enough to remove the effects of the REFL_L noise, which is concentrated in the few-Hz region in the LLO setup.

One more thing I forgot was the finite transmission of the steering mirror at the OMC input (the transmission of this mirror goes to the QPDs). This will add a fixed error of 0.3%, and I will take it into account in the future.

I found that, in fact, I had lowered the modulation depth since when I measured it to be 0.45 rads --> Psb = 0.1.

Here is the sweep measurement:

This is Psb = 0.06 --> gamma = 0.35 rads.

This changes the "raw transmission" and "coupling", but not the inferred visibility:

I also measured the cavity AMTF at three powers today: 0.5 mW, 10 mW, and 45 mW input.

They look about the same. If anything, the cavity pole seems slightly lower with the higher power, which is counterintuitive. The expected shift is very small (~10%), since the decay rate is still totally dominated by the mirror transmissions even for the supposed high-loss state (Sam and Sheon estimated the roundtrip loss at high power to be ~1400 ppm, while the combined coupling mirrors' T is 1.6%). I have not been able to fit the cavity poles consistently to within this kind of error.

[Koji, Zach]

Tonight, we locked the "fauxMC". We obtained a visibility of >99%.

Koji had aligned it roughly last night, but we wanted to have a couple steering mirrors in the path for this practice cavity (the periscope mirrors will serve this function in the real setup), so we marked the alignment with irises and installed two extra mirrors.

After obtaining flashes with the WinCam placed at the output coupler, we removed the WinCam and put a CCD camera at one of the curved mirror transmissions and used this to get a strong TEM₀₀ flash. Then, we installed the REFL PD/CCD, swept the laser PZT and optimized the alignment by minimizing the REFL dips. Finally, we connected the RF electronics and locked the cavity with the LB box. We used whatever cables we had around to trim the RF phase, and then Koji made some nice SMA cables at the 40m.

One thing we noticed was that we don't have enough actuation range to keep the cavity locked for very long---even with the HV amp (100V). We are going to offload to the NPRO temperature using an SR560 or pomona box circuit. We may also make an enclosure for the cavity to protect it from the HEPA blasting.

Tomorrow, after we do the above things, we will practice measuring the transmission, length (FSR) and mode spectrum of the cavity before moving on to the real McCoy.

That is an expanding fire pillow, also known as firebrick.  It is used to create a fire block where holes in fire-rated walls are made and prevents lab fires from spreading rapidly to adjacent labs.  I had to pull cable from B254 to our labs on either side during a rather narrow window of time.  Some of the cable holes are partially blocked, making it difficult to reach the cable to them. The cable is then just guided to the hole from a distance.  With no help, it's not possible to see this material getting shoved out of the hole.  I can assure you that I took great pains not to allow the CYMAC coax to fall into any equipment, or drag against any other cables.   

Summary of Zygo setups

Initial Zygo Setup:
Our initial Zygo setup consisted of a flat transmission sphere with the 0.5" curved mirror mounted against a 1" flat mirror.
Mounting procedure:
The bottom part of the gluing fixture was attached to a mounting plate using two screws. The 1" reference flat was placed on the gluing fixture. The reference flat was inspected with a green flashlight to ensure that there was no dust on the mirror surface. Any dust was removed using top gun. If any dust remained after using top gun, it was removed with a swab.
The back surface of the curved mirror was inspected and cleaned using the same method (flashlight inspection, followed by top gun if necessary, followed by swab if necessary).

After ensuring that both surfaces are clean, the back surface of the curved mirror was placed on the front surface of the reference flat. The fiducial of the curved mirror was positioned at 12:00. (12:00 is defined as the top of assembly.) The two mirrors were held in place using a mounting plate with a 0.4" aperture. The mounting plate was fixed to the bottom part of the gluing fixture using two screws and a spring for each screw (see attached picture).

The mounting plate holding this assembly was then attached to a optical mount with tip/tilt adjustments (see attached picture).
This assembly was placed facing the Zygo transmission flat (see attached picture) and the mount was pitched/yawed until the fringes on the 1" reference flat were nulled. After nulling the fringes, the data was then recorded.

The mounting plate was then removed from the tip/tilt mount and dissassembled so that the curved mirror could be rotated so that the fiducial is in the 3:00 position. The procedure is then repeated and the data recorded.
This was repeated again with the fiducial in the 6:00, 9:00 and 12:00 (again) positions.

Review of this data shows that the positions of the curvature minimums was not reproducible with sufficient precision. A teflon mounting plate was added to clamp the 1" reference flat more securely to the gluing fixture (See attached pictures). Data was collected in the same manner (twice with the fiducial at 12:00 and once with fiducial at each of the positions 3:00, 6:00, and 9:00).
Additional data collected still failed to produce reproducible results and the removing/remounting process of the curved mirror was time-consuming, so we attempted a new setup for the Zygo measurments.

Final Zygo Setup:
The new setup used a fold mirror mounted at 45degrees to direct the Zygo beam downwards into the plane of the table. A 3" flat was used as our reference flat. The reference flat was placed on some lens tissue parallel to the plane of the table. The same inspection and cleaning method was used to ensure that there was no dust on the reference flat (flashlight inspection, followed by top gun if necessary, followed by swabbing if necessary).
The back of the curved optic was inspected and cleaned using the same method. The curved mirror was placed on the 3" reference flat with the fiducial at the 12:00 position. (12:00 here is defined as the direction ponting towards the Zygo instrument.) (See attached picture of this setup.)
The fold mirror was pitched/yawed so that the fringes on the 3" reference flat were nulled. (An additional advantage of this setup is that more surface of the reference flat was viewable.) After nulling the fringes, the curved mirror was picked up and replaced a few times to verify that the fringe pattern on the curved mirror appeared reproducible. The data was collected with the fiducial at the 12:00 position. This process was repeated with the fiducial at 3:00, 6:00, 9:00, and again at 12:00.
Results from this setup were reproducible and this setup was used to measure the surface profile of all the curved mirrors.

[Camille, Koji]

Friday, Nov 11th, 2022

Setting up OMC #1 for transmission measurements:

The laser beam was aligned to the OMC cavity. The OMC cavity was locked and the transmission measurements were recorded.

The measured total optical loss of the OMC was

1st:   0.015 +/- 0.003
2nd: 0.085  +/- 0.005
3rd:  0.0585+/- 0.0008
4th:  0.047  +/- 0.002

In avegrage the estimated loss is
Loss = 0.055 +/- 0.014

This is unchanged from the measurement at LLO after the FC cleaning
Loss = 0.053 +/- 0.010