 Fri Dec 2 23:58:33 2022, Koji, Optics, Characterization, OMC #1 cleaning for water soluble contaminants 
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The second trial of the water scrub
A bright scatter is visible on FM1, so I tried water scrub on FM1. This time, both surfaces of FM1 and both surfaces of BS1 were cleaned.
Smaller Vectra swabs were used for the scrub. Then the water was purged by IPA splashed from a syringe. Right after that FC was applied. |
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Tue Nov 15 10:58:53 2022, Koji, Optics, General, OMC #1 damaged black glass removal
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[Camille, Koji]
The damaged black glass was removed from the OMC breadboard leaving the glass base.
The black glass pieces were bonded very tightly on the FS base with EP30-2. The apparent amount of the bond was not so much but it was such hard |
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Tue Nov 15 11:12:24 2022, Koji, Optics, General, OMC #1 fogging on the AR side of BS1 cleaned
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[Camille, Koji]
Photo of the BS1 AR cleaning process
Attachment 1: Before cleaning. Foggy surface is visible. |
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Thu Jan 26 23:46:13 2023, Koji, Optics, General, OMC #1 input beam dump bonding
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A beam dump was stacked on the base of the previous beam dump. The angle was determined so that the main transmission goes through while the stray OMC
reflection is blocked without clipping at the edge.
The resulting alignment of the beam dump is shown in Attachment 1. |
 Thu Jan 26 23:07:14 2023, Koji, Optics, General, OMC #4: Input beam dump bonding
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[Camille, Koji]
During the second UV epoxy session, we did not bond the input beam dump. This is because this beam dump was not the one planned from the beginning
and if it was bonded in place, it would have created difficulties when removing the template. |
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Thu Jan 26 22:57:19 2023, Koji, Optics, General, OMC #4: One Invar block bonded with tilt
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[Camille, Koji]
The bottom side template was separated into two pieces and successfully removed from the breadboard. The template was assembled together again
and bagged to store it in a cabinet. |
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Thu Feb 2 03:09:41 2023, Koji, Optics, General, OMC #4: One Invar block bonded with tilt
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[Camille, Thejas, Koji]
We added a reinforcement bar at the back of the invar block which had the tilt issue.
The reinforcement bar was added to the backside rather than the side or front such that the DCPD housing does not interfere with the reinforcement |
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Sat Feb 4 03:16:10 2023, Koji, Optics, General, OMC #4: One Invar block bonded with tilt
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The attached photo shows the resulting bond spread.
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Sat Jan 28 00:46:21 2023, Koji, Mechanics, General, OMC #4: Replaced the locks of the transport fixture
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Yesterday, we noticed that we could not close the transport fixture for OMC #4. We could not fully rotate the knobs of the locks. Today, I took the hooks
from the functioning locks of the spare transport fixture.
It turned out that the default dimension of the lock seemed too tight. The functioning one has the through holes elongated by a file or something. |
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Thu Jan 26 23:16:35 2023, Koji, Optics, Configuration, OMC #4: Top side bonding.
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[Camille, Koji]
1. Flipping the OMC |
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Thu Jan 19 23:45:44 2023, Koji, Optics, General, OMC #4: cavity mirror bonding
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[Koji, Camille]
We worked on the bonding of the flat mirrors for the OMC cavity with UV epoxy.
- Prepared the UV illumination setup. Cleaned up the table a bit to spare some space for the illuminator. |
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Mon Jan 23 19:51:20 2023, Koji, Optics, General, OMC #4: cavity mirror bonding
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[Camille, Koji]
We continued to bond two CM mirrors and the other two steering mirrors for QPD2.
Before the bonding work, the FSR and TMSs were checked again. |
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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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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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Thu Jun 15 13:13:57 2023, Koji, Electronics, Configuration, OMC (004) DCPD/QPD preparation
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Work log for June 14, 2023
Selected QPDs from the stock: QPD#62 for QPD1 and QPD#70 for QPD2 were selected from the QPD stock T1200063.
The
legs of the QPDs were trimmed so that the cable could completely flush with the mount.
A test PD (Excelitas) was mounted on a DCPD housing.
They |
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Mon Jul 10 20:23:47 2023, Koji, Optics, Characterization, OMC (004) Spot positions 10x
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Belated entry: OMC(004) Spot positions (Jun 15, 2023)
Photographs of the spot positions on the cavity mirrors and the DCPDs/QPDs as well as the reflected beams towards the beamdumps. |
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Mon Jul 10 20:52:19 2023, Koji, Optics, Characterization, OMC (004) TMS measurement
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| Belated entry: OMC(004) TMS measurement with the PZT voltages scanned (Jun 12/15, 2023) |
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Wed Feb 1 01:44:14 2023, Koji, General, General, OMC (004) plan
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2/1 2:30PM~ Bonding reinforcement (Last EP30-2 gluing)
2/2 1:00PM~ Peripheral attachment / Optical testing setup |
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Sun Jun 25 21:08:37 2023, Koji, General, Characterization, OMC (004) transported to Downs for cable furnishing
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| OMC (004) + the transport fixture was transported to Downs 227 with the boxes for OMC cabling hardware and DCPD/QPD connector parts. |
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Mon Aug 7 16:00:30 2023, Koji, General, General, OMC (004): Cable installation
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The writing of this elog is still on going
[Dean, Stephen, Koji]
4th OMC production was completed.
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Thu May 4 15:12:14 2023, Koji, General, Characterization, OMC (004): Final Testing
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FSR measurement (dip) - done May 3, 2023
FSR measurement (RFAM injection) - done May 3, 2023
TMS
measurement with PZT1/2 swept from 0V~200V - 1st session Jun 12, 2023 / 2nd session Jun 15
Mirror cleaning / Power budget
- done [OMC ELOG 530]
PZT response DC / AC - done May 17, 2023
DCPD |
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Tue May 16 10:26:12 2023, Koji, General, Characterization, OMC (004): Final Testing
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FSR measurement (dip) - done May 3, 2023
FSR measurement (RFAM injection) - done May 3, 2023
TMS
measurement with PZT1/2 swept from 0V~200V
Mirror cleaning / Power budget - done [OMC
ELOG 530]
PZT response DC / AC done May 11, 2023 [OMC ELOG 537]
DCPD |
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Mon Aug 7 16:01:05 2023, Koji, General, General, OMC (004): Production completed
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| OMC (004) Production completed. The OMC together with the transport fixture is still placed at the 40m clean room. |
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Tue May 14 19:06:00 2013, Koji, Clean, General, OMC Baking
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The OMC is in the air bake oven now.
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Fri Dec 13 14:59:18 2019, Stephen, General, General, OMC Beam Dump Production Cure Bake
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[Koji, Jordan, Stephen]
The beam dumps, bonded on Fri 06 Dec 2019, were placed in the newly tuned and configured small dirty ABO at the Bake Lab on Fri 13 Dec 2019.
Images are shared and references are linked below |
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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. |
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Mon Sep 28 16:03:13 2020, rana, General, General, OMC Beam Dump Production Cure Bake
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are there any measurements of the BRDF of these things? I'm curious how much light is backscattered into the incoming beam and how much goes
out into the world.
Maybe we can take some camera images of the cleaned ones or send 1-2 samples to Josh. No urgency, just curiosity. |
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Mon Sep 28 16:13:08 2020, Koji, General, General, OMC Beam Dump Production Cure Bake
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According to the past backscatter test of the OMC (and the black glass beamdump: not V type but triangular type on a hexagonal-mount), the upper limit
of the back reflection was 0.13ppm. https://nodus.ligo.caltech.edu:8081/OMC_Lab/209
I don't have a BRDF measurement. We can send a few black glass pieces to Josh. |
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Sat Apr 13 21:06:02 2013, Koji, Optics, General, OMC Bottom-side: cavity glued
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[Jeff, Zach, Lisa, Koji]
Gluing of the cavity mirrors went very well!!!
Preparation |
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Thu Aug 22 15:34:03 2013, Koji, Optics, General, OMC Cavity side gluing
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[Koji Jeff]
o BS1, FM1, FM2 prisms were glued
=> This fixed the unstability of the OMC locking |
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Thu Aug 20 01:35:01 2015, Koji, Electronics, General, OMC DCPD in-vacuum electronics chain test
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We wanted to know the transimpedance of the OMC DCPD at high frequency (1M~10M).
For this purpose, the OMC DCPD chain was built at the 40m. The measurement setup is shown in Attachment 1.
- As the preamp box has the differential output (pin1 and pin6 of the last DB9), pomona clips were used to measure the transfer functions |
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Wed Aug 26 11:31:33 2015, Koji, Electronics, General, OMC DCPD in-vacuum electronics chain test
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| The noise levels of the output pins (pin1/pin6) are measured. Note that the measurement is done with SE. i.e. There was no common mode noise rejection. |
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Mon Sep 18 15:08:26 2023, Thejas , Optics, General, OMC HEPA enclosure filter fan speed
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I went in lab today and turned the HEPA filter (clsoe to the entrance) to high since we are not doing any measurements at the moment.
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Thu Aug 3 09:42:36 2023, Thejas, Optics, General, OMC Lab HEPA air filter noise
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Koji mentioned that previously sarisfactory particle count was not acheived with the Med/Med HEPA filter setting once the enclosure was expanded, so
a higher setting was used. This imparted noise to the cavity from the turbulent air flo. We noticed that the noise level in the laser control
signal reduced with turning the HEPA filter next to the entrance to low and the current setting is Low/High. The particle count is zero (as below). |
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Sat Feb 4 03:33:22 2023, Koji, General, General, OMC Lab Inventory
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Attachment 1: North Cabinet 2nd from the left
Attachment 2: North Cabinet 3rd from the left
Attachment 3: South Cabinet (right) |
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Tue Mar 7 23:00:16 2023, Thejas , Optics, Characterization, OMC Lab clean up
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Today, Koji and I cleaned up the the lab space and made some space on the optical table for radius of curvature measurement of the A+ OMC curved
mirrors.
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Thu Jul 6 10:19:23 2023, Thejas , General, Characterization, OMC Lab optic table
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[Camille, Thejas]
The optics table in OMC lab was cleaned up, cameras and photodiodes used to measure the reflected and transmitted beam were unmounted to make
space for the new cavity. The input beam for the new cavity is injected from the short side (unlike the long side previously) of the breadboard. A 45deg |
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Fri Jul 15 22:14:14 2022, Koji, General, General, OMC Lab recovery for the OMC #002 test
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- The lab is chilly (18degC)
- Cleaned the lab and the optical table a bit so that the delicate work can be done. The diode test rig (borrowed from Downs - see OMC
ELOG 408 and OMC ELOG 409) was removed from the table and brought to the office (to return |
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Thu Nov 29 21:18:23 2012, Koji, Optics, General, OMC Mounting Prisms have come
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Tue Oct 22 10:25:01 2019, Stephen, General, General, OMC PZT Assy #9 and #10 Production Cure Bake
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OMC PZT Assy Production Cure Bake (ref. OMC elog 381) for PZT Assy #9 and #10 started 27
September 2019 and completed 28 September 2019. Captured in the below figure (purple trace). Raw data has been posted as an attachment as well.
We have monitored the temperature in two ways: |
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Fri Jun 15 15:45:49 2012, Koji, General, General, OMC Plan
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LIGO Document G1200683-v1:
aLIGO OMC fabrication and testing plan
aLIGO OMC wiki |
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Thu Apr 11 15:10:22 2013, Koji, General, General, OMC Progress
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[Zach, Jeff, Koji]
- Jeff configured the bottom side template to have a nominal value
obtained from the solid works model. Note that the thickness of the |
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Tue May 16 19:05:18 2017, Koji, Optics, Configuration, OMC SN002 fix - temporary optics
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| Working on the SN002 OMC fix. Checked the inventory. I think I am using C8 mirror as the new temporary CM1 and PZT24 as the new temporary CM2. |
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Thu Mar 14 17:06:21 2013, Koji, Mechanics, General, OMC SUS work @LLO
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EDIT (ZK): All photos on Picasa.
Also, I discovered that since Picasa was migrated to Google+ only,
you no longer have the option to embed a slideshow like you used to. Lame, Google. |
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Tue Oct 9 05:03:15 2012, Koji, Electronics, General, OMC Test Electronics Setup
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Tue Oct 9 04:59:24 2012, Koji, Optics, General, OMC Test Optical Setup
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Mon Mar 25 19:31:16 2013, Koji, Optics, General, OMC Top-side gluing
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[Koji Jeff Zach]
AAA
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Thu Mar 7 15:53:47 2013, Koji, Mechanics, General, OMC Transportation fixture, OMC PD/QPD mounts
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Fri Feb 5 07:40:37 2021, Stephen, Supply, General, OMC Unit 4 Build Machined Parts
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OMC Unit 4 Build Machined Parts are currently located in Stephen's office. See image of large blue box from office, below.
Loaned item D1100855-V1-00-OMC08Q004
to Don Griffith for work in semi-clean HDS assy. |
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Wed Jul 7 14:21:50 2021, Stephen, Supply, General, OMC Unit 4 Build Machined Parts
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More explicit insights into the inventory for the Unit 4 build. Image of inventory included below.
Machined Parts:
New fabrication = Contents of Storage-11112 are consistent with |