 Thu Jan 10 20:45:00 2019, Koji, Optics, Characterization, PZT test cable 
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As OMC SN002 already has the PZTs connected to the Mighty-Mouse connector, a test cable with a female mighty-mouse connector was made.
A small imperfection: When the cable was inserted to the connector shell, I forgot to mirror the pin out. Therefore the color and pin number
do not match. |
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Sat Jan 12 22:49:11 2019, Koji, Optics, Characterization, PM-SM patch cable mode cleaning effect
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Mode cleaning capability of an optical fiber was measured. The conclusion is that the
leakage of the non-fiber mode to the fiber output is insignificant and also practically negligible.
The tested fiber was Thorlabs 5-m Polarization Maintaining Single-Mode fiber (P3-1064PM-FC-5, PM Patch Cable, PANDA, 1064 nm, FC/APC, 5m). |
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Fri Feb 1 12:52:12 2019, Koji, Mechanics, General, PZT deformation simulation
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A simple COMSOL simulation was run to see how the PZT deforms as the voltage applied.
Use the geometry of the ring PZT which is used in the OMCs - NAC2124 (OD 15mm, ID 9mm, H 2mm)
The material is PZT-5H (https://bostonpiezooptics.com/ceramic-materials-pzt) which |
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Sat Feb 2 16:17:13 2019, Koji, Optics, Characterization, Summary: OMC(001) HOM structure recalculation
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Each peak of the transfer function measurement was fitted again with a complex function:
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Sat Feb 2 20:03:19 2019, Koji, Optics, Characterization, Summary: OMC(002) HOM structure recalculation (before mirror replacement)
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OMC (002)
History: Measurement date 2013/10/11, Installed to L1 2013/XX |
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Sat Feb 2 20:28:21 2019, Koji, Optics, Characterization, Summary: OMC(003) HOM structure recalculation
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OMC (003)
History: Measurement date 2014/7/5, Stored for I1, Installed to H1 2016/8 upon damage on 002 |
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Sat Feb 2 20:35:02 2019, Koji, Optics, Characterization, Summary: OMC(002) HOM structure recalculation (after mirror replacement)
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OMC (002) after repair
History:Mirror replacement after the damage at H1. Measurement date 2019/1/10 |
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Tue Mar 19 17:30:25 2019, Koji, General, Characterization, OMC (002) Test items
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OMC #002 Optical tests
FSR measurement (done, 2019/1/8-9, 2019/4/1)
TMS measurement
(done, 2019/1/9)
TMS measurement (with DC voltage on PZTs) (done, 2019/1/10)
Cleaning |
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Thu Mar 28 16:36:52 2019, Koji, Mechanics, Characterization, OMC(002) PZT characterization
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As performed in the ELOG 202, the PZTs of the OMC 002 were tested.
DC response was measured by sweeping each PZT with 0-150V triangular voltage at 11Hz. Acquire 0.2sec of the tie series using an oscilloscope
to get the PDH error, cavity transmission, and the sweep signal. |
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Thu Apr 4 20:07:39 2019, Koji, Supply, General, Purchase
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== Office Depot ==
Really Useful Box 9L x 6 (delivered)
Really Useful Box 17L x 5 (ordered 4/4) |
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Fri Apr 5 01:07:18 2019, Koji, Optics, Characterization, OMC(002): transmitted beam images
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There was a concern that the transmission from CM1 has additional fringes. The shape of the transmitted beams from CM1, CM2, and FM2 (main) werecaptured
with WinCamD.
Indeed CM1 and CM2 have the fringes, but it does not exist in the main transmission. So it seems that the fringes are associated with the curved |
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Fri Apr 5 01:08:17 2019, Koji, Optics, Characterization, OMC(002): DCPD / QPD alignment
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The beam height in the cavity became totally different from the previous one and the shims needed to be much thicker than before. This is probably because
of the alignment of the newly-glue curved mirror.
As the beam height is 2~2.5mm higher, two shims need to be stacked. The preliminary check of the heights using the alignment disks (dummy PDs) |
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Fri Apr 5 20:50:54 2019, Koji, Optics, Characterization, OMC(002): QPD alignment
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QPD# QPD1 QPD2
Housing# #004 #008
Diode# #44 #46 |
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Fri Apr 5 23:30:20 2019, Koji, General, General, OMC (002) repair completed
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OMC(002) repair completed
When the cable harness of OMC(004) is going to be assembled, the cable harness of OMC(002) will be replaced with the PEEK one. Otherwise, the
work has been done. |
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Wed Apr 10 19:22:24 2019, Koji, General, General, OMC(004): preparation for the PZT subassembly bonding
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Preparation for the PZT subassembly bonding (Section 6.2 and 7.3 of T1500060 (aLIGO OMC optical
testing procedure)
- Gluing fixture (Qty 4) |
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Thu Apr 11 12:15:31 2019, Koji, Mechanics, Configuration, PZT sub assy mirror orientations
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Thu Apr 11 21:22:26 2019, Koji, Mechanics, General, OMC(004): PZT sub-assembly gluing
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[Koji Stephen]
The four PZT sub-assemblies were glued in the gluing fixtures. There were two original gluing fixtures and two additional modified fixtures for
the in-situ bonding at the repair of OMC(002). |
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Thu Apr 11 21:22:58 2019, Koji, General, General, OMC(004): PZT sub-assembly air baking
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[Stephen Koji]
The baking of the PZT subassemblies was more complicated than we initially thought.
The four PZT subassemblies were placed in the air bake oven A. We meant to bake the assemblies with the ramp time of 2.5h, a plateau of 2h at |
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Sun Apr 14 23:58:49 2019, Koji, General, General, OMC(004): PZT sub-assembly post air-bake inspection
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[Koji Stephen]
(Friday afternoon) We retrieved the PZT sub-assemblies to the clean room.
We started removing the ASSYs from the fixtures. We noticed that some part of the glass and PZT are ripped off from the ASSY and stuck with the |
 Mon Apr 15 00:08:32 2019, Koji, General, General, OMC(004): PZT sub-assembly post air-bake inspection (Sub-assy #7) 6x
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Sub-ASSY #7
Probably the best glued unit among the four.
Attachment #1: Mounting Block SN001 |
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Mon Apr 15 00:39:04 2019, Koji, General, General, OMC(004): PZT sub-assembly post air-bake inspection (Sub-assy #8) 8x
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Sub-ASSY #8
Probably the best glued unit among the four.
Attachment #1: Mounting Block SN007 |
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Mon Apr 15 01:07:30 2019, Koji, General, General, OMC(004): PZT sub-assembly post air-bake inspection (Sub-assy #9) 7x
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Sub-ASSY #9
The most fractured unit among four.
Attachment #1: Mounting Block SN017 |
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Mon Apr 15 01:23:45 2019, Koji, General, General, OMC(004): PZT sub-assembly post air-bake inspection (Sub-assy #10)
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Sub-ASSY #10
Attachment #1: Mounting Block SN021
Attachment #2: PZT-Mounting Block bonding looks just excellent. |
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Tue Apr 16 11:36:36 2019, Koji, Optics, Characterization, OMC(004): PZT testing for spare OMC 9x
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Attachment 1: Shadow sensor setup for the PZT displacement test
Attachment 2: PZT endurance test. 4 PZTs were shaken at once.
Attachment 3~5: Function generator setup 100Hz, 3.5Vpp 1.75Voffset (meant be displayed for 50Ohm load) |
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Tue Apr 16 16:35:09 2019, Koji, Optics, Configuration, OMC(004): Glass breadboard selection
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D1200105 SN006 was selected as the breadboard for OMC(004).
The reason is the best parallelism among the unused ones.
The attached is the excerpt from T1500060 with the #006 highlighted. |
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Tue Apr 16 16:40:26 2019, Koji, General, Configuration, OMC(004): A Mirror selection
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We are going to use A5 and A14 for FM1 and FM2. (The role of these two can be swapped)
The reason for the selection is the better perpendicularity among the available prisms.
A11 has the best perpendicularity among them. However, the T didn't match with the others. The pair of A5 and A14 has a good matching with |
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Tue Apr 16 16:52:36 2019, Koji, Optics, Configuration, OMC(004): B Mirror selection
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We are going to use B6 for the DCPD BS (BS2), and B1 for the QPD BS (BS3). Their role can not be swapped.
B6 has the best loss among the available ones, while the perpendicularity is not so critical due to the short arm.
B1 has the OK perpendicularity, while the loss is also moderately good. |
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Tue Apr 16 17:24:56 2019, Koji, Optics, Configuration, OMC(004): E Mirror selection
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We are going to use E6, E9, E11, and E14 for BS1, SM1, SM2, and SM3. They (and E18) are all very similar.
The attachment is the excerpt from T1500060 with some highlighting |
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Tue Apr 16 21:16:11 2019, Koji, Optics, Characterization, OMC(004): PZT testing for spare OMC
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After having dug into the past email, it turned out that these wires were the ones already replaced from the original teflonwires. The length of them
were confirmed to be ~19" (480mm).
Quote:
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Tue Apr 16 23:11:43 2019, Koji, General, General, Borrowed items from the other labs
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Apr 16, 2019
Borrowed two laser goggles from the 40m. (Returned Apr 29, 2019)
Borrowed small isopropanol glass bottole from CTN. |
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Fri Apr 19 11:34:19 2019, Koji, Optics, , OMC initial alignment and locking
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The spot on CM1 was found displaced by 3.4mm (horiz.) and 3.0mm (vert.) in the upper right direction looking from the face side.
The spot on CM2 was found displaced by 1.2mm (horiz.) and 1.8mm (vert.) in the upper left direction looking from the face side.
The drawing on the left side of the attachment shows the estimated misalignment when we think they all come from the curved |
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Sat Apr 20 00:50:12 2019, Koji, Optics, Characterization, OMC(004): Spot positions
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Similarly to OMC ELOG 349 the spot positions after the replacement of CM2 were measured
(Attachment 1)
Also, the spot positions after the realignment were measured. (Attachment 2) |
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Mon Apr 22 19:54:28 2019, Koji, General, , OMC(004): Spot positions at the end of Apr 22nd
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Wed May 1 15:40:46 2019, Koji, Optics, Characterization, OMC(004): Spot positions and the scattering
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Tried a few things.
1. Replaced CM1 (PZT ASSY #10=M21+PZT#22+C12) with PZT ASSY #7 (=M1+PZT#13+C13)
We tried PZT ASSY #7 at the beginning and had the spots at almost at the top edge of the curved mirrors. As we found a particle on the bottom |
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Fri May 3 11:06:28 2019, Koji, Optics, Characterization, OMC(004): Spot positions and the scattering
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Experiment on 5/1
- CM1 right knob was moved 1div (10um) backward such that the spots were better centered on the mirrors
FM1 (A5): h=-0.2mm -> 0.4mm made the spot much darker but still it has a few scattering spots. |
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Thu May 9 17:35:07 2019, Koji, Optics, General, Alignment strategy
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Notes on the OMC cavity alignment strategy
- x3=1.17 γ + 1.40 δ, x4=1.40 γ + 1.17 δ
- This means that the effect of the two curved mirrors (i.e. gouy phases) are very similar. To move x3 and x4 in common is easy, but to do differentially |
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Thu May 9 18:10:24 2019, Koji, Optics, Characterization, OMC(004): Spot position scan / power budget
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(Now the CCD image is captured as a movie and the screen capture is easier!)
Various spot positions on CM1 and CM2 were tried to test how the transmission is dependent on the spot positions. CM1 has a
few bright spots while CM2 shows very dark scattering most of the case. Attachment 1 is the example images of one of the best alignment |
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Wed May 15 19:07:53 2019, Koji, Clean, General, What is this???
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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. |
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Mon May 20 19:53:17 2019, Koji, Optics, Configuration, DCPD high power test
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We want to perform a damage test of OMC DCPDs with high power beam. The OMC DCPD is the 3mm InGaAs photodiodes with high quantum efficiency, delivered
by Laser Components.
The sites want to know the allowed input power during the OMC scan for beam mode analysis. The nominal bias voltage of the PDs is +12V. Therefore, |
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Wed May 22 07:31:37 2019, Koji, Optics, Configuration, Camera test (DCPD high power test)
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C30665 (3mm) camera test. The camera was Canon PowerShot G7X MkII. Exposure 1/15s, F 5.6, ISO 125, MF (~the closest), no zoom.
This image was taken before the beam illumination. Will tune the green lighting to have some gradient on the surface so that we can see any deformation
of the surface. |
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Thu May 23 01:42:46 2019, Koji, Optics, Characterization, C30665 high power test
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An Excelitas C30665 PD with the cap removed (SN07 in Case H slot #2) was exposed to the beam with the optical power of 1.4mW to 334mW.
After each illumination, the dark current and the dark noise level were tested. Also the photo image of the PD surface was taken each time.
- No significant change of the dark current after each illumination. |
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Thu May 23 23:27:38 2019, Koji, Optics, Characterization, IGHQEX3000 high power test
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LaserComponents IGHQEX3000 (Cage B2: Serial# B1-23) was exposed to the beam with the optical power from 1.6mW to 332mW.
After each illumination, the dark current and the dark noise level were measured. Also the photo image of the PD surface was taken each time.
- No significant change of the dark current after each illumination. |
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Mon Jun 24 12:54:58 2019, Koji, Clean, General, HEPA BOOTH
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| https://www.airscience.com/purair-flow-laminar-flow-cabinets |
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Mon Jul 1 12:38:49 2019, Koji, Optics, Characterization, A and M prisms perpendicularity measurement 6x
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[Stephen, Koji]
The perpendicularity of some of the A and M prisms were tested.
Results |
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Mon Jul 1 12:49:42 2019, Koji, Optics, Characterization, Scattering measurement of A and C mirrors
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| Liyuan's scattering measurement for the A and C mirrors. |
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Mon Sep 23 21:29:51 2019, Koji, Optics, General, OMC(004): PZT sub-assembly gluing (#9/#10)
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[Stephen, Shruti, Koji]
We worked on the gluing of the PZT sub-assy (#9 and #10) along with the designed arrangement by Shruti (OMC
ELOG 374). |
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Mon Sep 30 23:16:53 2019, Koji, Optics, General, OMC(004): PZT sub-assembly gluing (#9/#10)
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Friday: [Stephen, Koji]
As the oven setting has qualified, we brought the PZT assys in the air bake oven.
Monday: [Stephen, Shruti, Koji] |
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Tue Oct 22 15:54:59 2019, Koji, Electronics, Loan / Lending, Borrowed LB1005 from Cryo Cav
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From Cryo Cav setup
Borrowed LB1005 Servo box -> OMC
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Fri Dec 6 00:55:25 2019, Koji, Optics, General, Beamdump gluing 6x
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[Stephen, Koji]
20 glass beamdumps were bonded at the 40m cleanroom.
Attachment 1: We had 20 fused silica disks with a V-groove and 40 black glass pieces |
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Wed Dec 18 21:54:53 2019, Koji, General, General, OMC Beam Dump Production Cure Bake
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The beamdumps were taken out from the oven and packed in bags.
The bottom of the V are completely "wet" for 17 BDs among 20 (Attachment 1/2).
3 BDs showed insufficient glue or delamination although there is no sign of lack of rigidity. They were separated from the others in the pack. |