 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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Mon Apr 15 21:11:49 2019, Philip, Optics, Characterization, OMC(004): PZT testing for spare OMC
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[Koji, Philip]
Today we tested the functionality of the four remaining PZTs (11,12,13 and 22) . Each PZT was placed within a collimated 500um beam.
Roughly half of the beam was blocked by the PZT. The PZT and a PD then acted as shadow sensor. Each PZT was tested with 0 and |
 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 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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Wed Apr 17 09:08:47 2019, Stephen, General, General, OMC(004): Unwrapping and preparing breadboard
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[Stephen, Philip, Koji, Joe]
Breadboard D1200105 SN06 was selected as described in eLOG 338. This log describes
unwrapping and preparation of the breadboard. |
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Wed Apr 17 10:30:37 2019, Philip, Optics, General, OMC optical set-up day 1
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[Joe, Koji, Liyuan, Philip, Stephen]
Work done on 16.04.2019
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Fri Apr 19 09:21:07 2019, Philip, Optics, , Cleaning of OMC optics
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ach[Joe, Phillip, Koji, Stephen]
Work from 17.04.2019
First contact cleaning of OMC optics |
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Fri Apr 19 09:35:28 2019, Joe, General, , Adjusting cavity axis, re-alignment of OMC and locking
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[koji,philip, joe, liyuan, steven]
*still need to add photos to post*
PZT 11 was removed and inspected for so dust/dirt on the bottom of the prism. We saw a spot. We tried to remove this with acetone, |
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Thu Apr 18 20:47:54 2019, Joe, Optics, , OMC initial alignment and locking
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[Joe, Phillip, Koji, Stephen]
*draft post, please add anymore info if I missed something*
made initial alignment of the cavity. To do this we used the periscope mirrors to aim the incoming beam at the centre of the |
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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 09:54:21 2019, Joe, General, , Shortening cavity (A5,A14,PZT11,PZT22) to get closer to design FSR
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[Koji,Joe,Philip,stephen]
in units 20um per div on the micrometer [n.b. we reailised that its 10um per div on the micrometer]
CM1 inner screw pos: 11.5 |
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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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| |
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Tue Apr 23 10:21:12 2019, Joe, Optics, Configuration, Moving the spots to the centre of the curved mirrors
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[Koji,Philip, Liyuan, Joe]
CM1:
We moved the curved mirrors to these positions: |
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Wed Apr 24 13:58:51 2019, Joe, Optics, Characterization, OMC power budget and UV Epoxy Bonding of BS1
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[koji,philip,joe,liyuan,stephen]
need to add spot positions.
Mirrors: PZT11,PZT22, A14, A5 |
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Thu Apr 25 15:05:19 2019, Joe, Optics, Characterization, Looking at PZT HOM spacing dependance and thinking about workflow
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[koji, joe]
The template or glass breadboard was wobbling, and we noticed that the caivty alignment became worse/better when it was pressed down. We saw
that it was the glass breadboard, so it was fixed into the transport fixture more securely. Now its alignement didn't change when it was pressed down. |
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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 16:07:18 2019, Stephen, Mechanics, General, Improvements to OMC Bonding Fixture
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[Stephen, Koji]
As mentioned in eLOG 331, either increased thermal cycling or apparent improvements
in cured EP30-2 strength led to fracture of curved mirrors at unintended locations of bonding to the PEEK fixture parts. |
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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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Thu May 16 12:41:28 2019, Chub, General, General, fire pillow found on optics table
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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. |
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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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Tue May 28 12:14:20 2019, Stephen, Optics, General, CM PZT Assembly Debonding of EP30-2 in Acetone 8x
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[LiyuanZ, StephenA]
Downs B119
Summary: Beginning on 20 May 2019, two CM PZT assemblies were soaked in Acetone in an effort to debond the EP30-2 bonds |
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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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Fri Aug 23 11:11:44 2019, shruti, Optics, Characterization, Finding the curvature bottom
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I attempted to fit the data taken by Koji of the beam spot precession at the CCD in order to find the location of the curvature bottom in terms
of its distance (d) and angle () from the centre of the mirror. This was done using
the method described in a previous similar measurement and Section 2.1.3 of |
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Thu Jan 10 18:37:50 2013, Koji, Optics, Characterization, Wedging of the PZTs
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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. |
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Thu Aug 22 12:35:53 2019, Stephen, Optics, Characterization, Wedging of the debonded PZTs 2019 August
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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 |
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Thu Aug 29 11:51:49 2019, shruti, Optics, Characterization, Wedging of the debonded PZTs - Calculation
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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: |
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Thu Sep 5 15:40:42 2019, shruti, Optics, Configuration, PZT Sub-Assembly
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Aim: To find the combinations of mounting prism+PZT+curved mirror to build two PZT sub-assemblies that best minimises the total vertical beam
deviation.
(In short, attachment 1 shows the two chosen sets of components and the configuration according which they must be bonded
to minimize the total vertical angular deviation.) |
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Wed Sep 18 22:30:11 2019, Stephen, Supply, General, EP30-2 Location and Status
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Here is a summary of the events of the last week, as they relate to EP30-2.
1) I lost the EP30-2 syringes that had been ordered for the OMC, along with the rest of the kit.
Corrective action: Found in the 40m Bake Lab garbing area.
Preventative action: log material moves and locations in the OMC |
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Wed Sep 18 23:16:06 2019, Stephen, Supply, General, Items staged at 40m Bake Lab for PZT Subassembly Bonding
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The following items are presently staged at the 40m Bake Lab (see photo indicating current location) (noting items broght by Koji as well):
Bonding fixtures, now modified with larger washers to constrain springs, and with modification from OMC
elog 358.
Curved Mirrors and Tombstones as selected by Shruti in OMC elog 374.
PZTs |
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Wed Sep 18 23:38:52 2019, Stephen, General, General, Dirty ABO ready for PZT Subassembly Bonding
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The 40m Bake Lab's Dirty ABO's OMEGA PID controller was borrowed for another oven in the Bake Lab, so I have had to play
with the tuning and parameters to recover a suitable bake profile. This bake is pictured below (please excuse the default excel formatting).
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Tue Sep 24 12:19:20 2019, Stephen, General, General, Dirty ABO test run prior to PZT Subassembly Bonding
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The 40m Bake Lab's Dirty ABO's OMEGA PID controller was borrowed for another oven in the Bake Lab (sound familiar? OMC
elog 377), so I have had to play with the tuning and parameters to recover. This bake seemed to inadequately match the intended temperature profile
for some reason (intended profile is shown by plotting prior qualifying bake for comparison). |
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Thu Sep 26 17:33:52 2019, Stephen, General, General, Dirty ABO test run prior to PZT Subassembly Bonding - ABO is Ready!
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Follow up on OMC elog 379
I was able to obtain the following (dark blue) bake profile, which I believe is adequate for our needs.
The primary change was a remounting of the thermocouple to sandwich it between two stainless steel masses. The thermocouple bead previously was |
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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 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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Tue Oct 22 11:52:53 2019, Stephen, General, General, Epoxy Curing Timeline of OMC PZT Assy #9 and #10
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This post captures the curing timeline followed by OMC PZT Assys #9 and #10.
Source file posted in case any updates or edits need to be made. |
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Tue Oct 22 11:56:09 2019, Stephen, Supply, General, Epoxy Status update as of 22 October 2019
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The following is the current status of the epoxies used in assembly of the OMC (excerpt from C1900052)
Re-purchasing efforts are underway and/or complete
DONE
Masterbond EP30-2 currently located in Downs 303, Modal Lab (see image)
( WILL EXPIRE JANUARY 2020 |
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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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Thu Jul 31 15:07:53 2014, Koji, General, General, Item lending
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Tara: Laser Safety goggle -> Returned
Evan:
HP signal generator (990MHz) (prev. setting 32.7MHz / +3dBm) |
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Fri Jan 30 19:31:08 2015, Koji, General, General, Item lending
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Gabriele:
PZT HV Amp
Evan: |
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Tue Feb 3 18:23:49 2015, Koji, General, General, Item lending
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- The laser was removed and shipped to LHO today.
- UV illuminator / fused silica fiber light guide / UV power meter / UV face shield (Qty 2) will be shipped to MIT.
They are CIT properties except for the illuminator. |
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Wed Feb 4 20:07:24 2015, Koji, General, General, Item lending
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Shipment to MIT (L. Barsotti, J. Miller)
1. UV Illuminator (LESCO Super Spot MK III)
2. UV Power meter (American Ultraviolet AIB1001) Caltech property C30140 |
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Tue Jul 21 20:20:12 2015, Koji, General, General, Item lending
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Kate (ATF)
- 4ch color oscilloscope (Tektronix)
- Chopper controller |
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Fri Sep 9 14:34:31 2016, Koji, General, General, Item lending
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To 40m
First Contact Kit by Calum
Class A Kapton sheets |
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Thu Feb 27 14:31:13 2020, Koji, General, General, Item lending
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Item lending as per Ian's request: Particle Counter from OMC Lab to QIL
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Mon Aug 10 15:29:54 2020, Koji, General, General, Item lending
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The particle counter came back to the OMC lab on Aug 10, 2020
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Mon Aug 10 15:34:04 2020, Koji, Facility, Loan / Lending, Glue bake oven
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| Black and Decker Glue Baking Oven came back to the OMC lab on Aug 10, 2020, Georgia had lent the unit for the SAMS assembly/testing. |
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Mon Aug 10 15:53:46 2020, Koji, General, General, Lab status check
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Check-in to the OMC lab to see the status. Nothing seemed changed. No bug. The HEPA is running normal. The particle level was 0.
Went into the HEPA enclosure and put a cover on the OMC. Because of the gluing template, the lid could not be close completely (that's expected
and fine). |
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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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Thu Oct 8 19:55:22 2020, Koji, General, Characterization, Power Measurement of Mephisto 800NE 1166A
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The output of Mephisto 800NE (former TNI laser) was measured.
The output power was measured with Thorlabs sensors (S401C and S144C). The reference output record on the chassis says the output was 837mW at 2.1A
injection. |
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Fri Oct 9 01:01:01 2020, Koji, General, General, TFT Monitor mounting
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To spare some room on the optical table, I wanted to mount the two TFT monitor units on the HEPA enclosure frame.
I found some Bosch Rexroth parts (# 3842539840) in the lab, so the bracket was taken for the mount. This swivel head works very well. It's rigid
and still the angle is adjustable. |
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Fri Oct 16 00:53:29 2020, Koji, General, General, TFT Monitor mounting
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The image flipping of the display unit was fixed. The vendor told me how to fix it.
- Open the chassis by the four screws at the side.
- Look at the pass-through PCB board between the mother and display boards. |
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Fri Oct 23 19:09:54 2020, Koji, General, General, Particle counter transfered to Radhika
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| See this entry: https://nodus.ligo.caltech.edu:8081/40m/15642 |
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Fri Nov 6 18:38:00 2020, Koji, General, General, Powermeter lent from OMC Lab to 2um ECDL
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Thorlabs' powermeter controler + S401C head was lent from OMC Lab. Returned to OMC Jul 15, 2022 KA
https://nodus.ligo.caltech.edu:8081/SUS_Lab/1856 |
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Fri Nov 20 18:51:23 2020, Koji, General, General, Instrument loan
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FEMTO DLPCA200 low noise preamp (brand new)
Keithley Source Meter 2450 (brand new) => Returned 11/23/2020
were brought to the OMC lab for temporary use. |
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Sat Nov 21 13:58:30 2020, Koji, Electronics, Characterization, Dark Current Measurement for InGaAs QPDs
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Dark current measurement for InGaAs QPDs (OSI FCI-InGaAs-Q3000) has been done using Keithley 2450 and Frank's diode test kit. Frank's setup uses
various custom instruments which are no longer exist, therefore the kit was used only for switching between the segments.
The diodes were serialized as 81, 82, 83, 84, continuing the numbering for the OMC QPDs. The numbers are engraved at the side and the back of |
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Sun Nov 22 13:49:12 2020, Koji, Electronics, Characterization, Impedance Measurement for InGaAs QPDs
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To know any anomaly to the junction capacitance of the QPD segments, the RF impedances were tested with a hand-made impedance measurement.
All segments look almost identical in terms of capacitance.
Measurement setup: |
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Mon Nov 23 23:17:19 2020, Koji, Electronics, Characterization, The dark noise of the Q3000 QPDs
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The dark noise levels of the four Q3000 QPDs were measured with FEMTO DLPCA200 low noise transimpedance amp.
The measurement has been done in the audio frequency band. The amp gain was 10^7 V/A. The reverse bias was set to be 5V and the DC output of
the amplifier was ~40mV which corresponds to the dark current of 4nA. It is consistent with the dark current measurement. |
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Tue Nov 24 10:45:07 2020, gautam, Electronics, Characterization, The dark noise of the Q3000 QPDs
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I see that these measurements are done out to 100 kHz - I guess there is no reason to suspect anything at 55 MHz which is where this QPD will be reading
out photocurrent given the low frequency behavior looks fine? The broad feature at ~80 kHz is the usual SR785 feature I guess, IIRC it's got to do
with the display scanning rate. |
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Tue Nov 24 12:27:18 2020, Koji, Electronics, Characterization, The dark noise of the Q3000 QPDs
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The amplifier BW was 400kHz at the gain of 1e7 V/A. And the max BW is 500kHz even at a lower gain. I have to setup something special to see the RF band
dark noise.
With this situation, I stated "the RF dark noise should be characterized by the actual WFS head circuit." in the 40m ELOG. |