 Sun May 30 15:17:16 2021, Koji, General, General, DCPD AF capacitance measirement 
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Attachment 1: System diagram. The reverse bias voltage is controlled by DS335. This can produce a voltage offset up to 10V. A G=+2 opamp
circuit was inserted so that a bias of up to +15V can be produced. The capacitances of the photodiodes were measured with SR720 LCR meter with a probe.
DS335 and SR720 were controlled from PC/Mac via serial connections. |
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Sun May 30 15:32:56 2021, Koji, General, General, DCPD AF capacitance measirement
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Measurement result:
The capacitance at no bias was 460~500pF. This goes down to below 300pF at 1.0~1.5V reverse bias. At maximum +15V, the capacitance goes down
to 200~220pF. |
 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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Thu Apr 18 11:59:02 2013, Koji, General, General, DCPD path gluing
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[Jeff, Koji]
DCPD path gluing
Usual preparation |
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Thu May 23 23:41:48 2013, Koji, Mechanics, General, DCPD/QPD Mount
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DCPD mounts and QPD mounts were attached on the breadboard. They are not aligned yet and loosely fastened.
DCPD (mounting 4-40x5/16 BHCS Qty4)
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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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Sat Feb 20 19:11:22 2016, Koji, Electronics, Characterization, Dark current measurement of the HQE PD and other PDs
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Dark current of the HQE PD and other PDs were measured.
- The HQE PDs were loaded on the new PD transportation cages (Attachment 1)
The PDs are always shorted by a clean PD plugs. The PD element is still capped with Kapton seals. |
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Sun Mar 13 21:22:27 2016, Koji, Electronics, Characterization, Dark current measurement of the HQE PD and other PDs
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Transfered for RGA scan
B4 (C1-05) -> F1
C1 (C1-07) -> F2 |
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Tue Dec 15 13:42:37 2015, Koji, Optics, Characterization, Dimensions / packaging of HQE PDs
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The dimensions of a high QE PDs was measured as well as the ones for C30665. (Attachment 4, Unit in mm)
They seemed to be very much compatible.
The PDs came with the designated case (Attachment 1). The bottom of the case has a spongy (presumably |
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Sat Mar 23 16:36:15 2013, Koji, Electronics, Characterization, Diode QE measurement
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Quantum efficiencies of the C30665GH diodes were measured.
- The diode was biased by the FEMTO preamplifier.
- Diode Pin 1 Signal, Pin 2 +5V, Pin 3 open |
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Fri Mar 15 02:15:45 2013, Koji, Electronics, Characterization, Diode testing
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Diode testing
o Purpose of the measurement
- Test Si QPDs (C30845EH) for ISC QPDs Qty 30 (i.e. 120 elements) |
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Sun Mar 17 21:59:47 2013, Koji, Electronics, Characterization, Diode testing ~ DCPD
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- For the dark noise measurement, the lid of the die-cast case should also contact to the box for better shielding. This made the 60Hz lines almost completely
removed, although unknown 1kHz harmonics remains.
- The precise impedance of the setup can not be obtained from the measurement box; the cable in between is too long. The diode impedance should |
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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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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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Thu Feb 7 21:35:46 2013, Koji, General, General, Dmass's loan of LB1005 / A2&C2 sent to Fullerton / First Contact @40m
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Dmass borrowed the LB1005 servo amp from the OMC lab.
It happened this week although it seems still January in his head. Got it back on Mar 24th
The A2 and C2 mirrors have been sent to Josh Smith at Fullerton for the scatterometer measurement. |
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Fri Jun 28 12:20:49 2013, Koji, General, General, Dmass's loan of Thorlabs HV amp
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http://nodus.ligo.caltech.edu:8080/Cryo_Lab/799
(KA: Returned upon H1OMC building) |
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Fri Jun 23 10:55:07 2017, Koji, Optics, General, Dust layer on black glass beam dumps?
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I wondered why the black glass beam dumps looked not as shiny as before. It was in fact a layer of dusts (or contaminants) accumulated on the surface.
The top part of the internal surface of the black glass was touched by a piece of lens tissue with IPA. The outer surface was already cleaned. IPA
did not work well i.e. Required multiple times of wiping. I tried FirstContact on one of the outer surface and it efficiently worked. So I think the internal |
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Wed Jul 15 22:23:17 2015, Koji, Electronics, AM Stabilized EOM Driver, E1400445 first look
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This is not an OMC related and even not happening in the OMC lab (happening at the 40m), but I needed somewhere to elog...
E1400445 first look
LIGO
DCC E1400445 |
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Mon Oct 8 11:30:47 2012, Koji, Optics, General, EG&G 2mm photodiode angle response
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| EGE&G 2mm photodiode angle response measured by Sam T1100564-v1 |
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Tue Dec 15 13:38:34 2015, Koji, Electronics, Characterization, EOM Driver linearity check
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Linearity of the EOM driver was tested. This test has been done on Nov 10, 2015.
- Attachment 1: Output power vs requested power. The output start to deviate from the request above 22dBm request.
- Attachment 2: Ctrl and Bias voltages vs requested power. This bias was measured with the out-of-loop channel. |
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Tue May 15 19:53:45 2018, Koji, Optics, General, EOM Q comparison
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Qs' were estimated with a lorentzian function (eye fit)
Current LHO EOM (final version, modulation depth measurement 2018/4/5) |
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Wed Jul 4 18:30:51 2018, Koji, Electronics, Characterization, EOM circuit models
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The circuit models for the 3IFO EOM (before mods) were made using LISO.
Then the modification plan was made to make it a new LLO EOM.
Impedance data, LISO model, Mathematica files are zipped and attached at the end. |
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Wed May 30 16:40:38 2018, Koji, Mechanics, Characterization, EOM mount stability test
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| https://awiki.ligo-wa.caltech.edu/wiki/EOM_Mount_Stability |
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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 Apr 3 18:42:45 2013, Koji, Optics, General, EP30-2 gluing test
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EP30-2 gluing test
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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 Jul 8 04:08:06 2014, Koji, General, General, Expoxy reapplication for beam dumps
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Firstly, the excess epoxy was removed using a cleaned razor balde
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Tue Jan 22 11:10:25 2013, Koji, Facility, General, Eyeware storage and hooks for the face shields are installed
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| A carpenter has come to install the eyeware storage and hooks for the face shields. |
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Thu Jan 10 20:42:54 2019, Koji, Optics, Characterization, FSR / HOM Test of OMC SN002
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OMC SN002 = Former LHO OMC which CM1 was destroyed by the lock loss pulse in 2016. This OMC needs to be optically tested before storage.
The test items:
[done] FSR measurement with offset PDH locking (FM->AM conversion)
[done] FSR/finesse |
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Sun Jul 6 02:45:56 2014, Koji, Optics, General, FSR Measurement
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3rd OMC FSR / Finesse measurement
RF AM was injected by detuning a HWP. |
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Wed May 14 02:15:15 2014, Koji, Optics, Characterization, FSR/TSM adjustment of the OMC cavity
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1. FSR was adjusted and measured with "the golden arches" technique again.
FSR = 264.8412 MHz +/- 1400Hz => Lcav = 1.13197 m. (nominal 1.132m)
2. Transverse mode spacings for the vertical and horizontal modes were measured. |
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Mon Apr 1 03:13:41 2013, Koji, Optics, General, Failure of PZT-glass joints
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[Koji, Jeff, Zach, Lisa]
We glued a test PZT-mirror assembly last week in order to make sure the heat cure of the epoxy does not make any problem
on the glass-PZT joints. The assembly was sent to Bob for the heat treatment. We received the assembly back from Bob on Wednesday. |
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Mon Apr 8 23:42:33 2013, Koji, Optics, Configuration, Fake OMC roughly aligned
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Mode matching:
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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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Wed Dec 19 18:47:03 2012, Koji, Clean, General, First Contact Training with Margot
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Steve and I visited Margot to have a training session for application of First Contact on optics.
- Make "thick" layer of first contact. It becomes thin when it gets dried.
- Apply more FC once a peek sheet is placed on the FC |
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Wed Jan 2 07:45:39 2013, Koji, Optics, Characterization, First Contact test
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Conclusion: Good. First contact did not damage the coating surface, and reduced the loss
- Construct a cavity with A1 and C2
- Measure the transmission and FWHM (of TEM10 mode) |
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Wed Aug 1 19:35:00 2012, Koji, Facility, General, Floor cleaned / Workbench being built / Table top defect
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- The floor of the room was cleaned and waxed!
- Sticky mats are placed! Now we require shoe covers!
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Tue Apr 16 08:12:14 2013, Koji, Optics, Characterization, Further More Mirror T measurement
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T&Rs of the B mirrors and some of the E mirrors are measured.
I found that these BSs have high loss (1%~3%) . As this loss will impact the performance of
the squeezer |
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Tue Apr 16 23:26:51 2013, Koji, Optics, Characterization, Further More Mirror T measurement
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Since the previous measurement showed too high loss, the optical setup was checked.
It seemed that a PBS right before the T&R measurement setup was creating a lot of scattering (halo) visible with a sensor card.
This PBS was placed to confirm the output polarization from the fiber, so it was ok to remove it. |
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Mon Dec 31 03:11:45 2012, Koji, Optics, Characterization, Further more RoC measurement
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Total (excluding C2, C7, C8): 2.575 +/- 0.005 [m]
New results
C6: RoC: 2.57321 +/− 4.2e-05m |
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Fri Nov 9 00:43:32 2012, Koji, Optics, Characterization, Further more wedge measurement
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Now it's enough for the first OMC (or even second one too).
Today's measurements all distributed in theta>0.5deg. Is this some systematic effect???
I should check some of the compeled mirrors again to see the reproducibility... |
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Tue Dec 29 12:15:46 2015, Koji, General, General, Glasgow polarizer passed to Kate
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| The Glasgow polarizer was passed to Kate on Dec 17, 2015. |
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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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Fri Aug 30 12:14:50 2013, Koji, Optics, General, H1 OMC Cavity length adjustment
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Short conclusion:
The roundtrip cavity length for the H1 OMC was adjusted to be 1.145m
instead of 1.132m such that the 19th HOMs of the lower sideband do not get resonant together with the carrier. |
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Fri Aug 30 12:22:56 2013, Koji, Optics, General, H1 OMC Cavity side UV gluing
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H1 OMC Cavity side optics was glued on the breadboard
Curved mirror gluing
- Applied the UV glues to CM1/CM2 prisms. |
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Fri Aug 12 14:58:17 2016, Koji, General, Configuration, H1 OMC DCPD replacement
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Preparation of 3rd OMC for the use in H1
New DCPD(T) = B1-01
DCPD(T) = DCPDA: extracted and accomodated in CAGE-A SLOT1 |
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Fri Aug 30 12:25:29 2013, Koji, General, General, H1 OMC Invar mount gluing
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The Invar Mounting Blocks were glued on the breadboard.
Serial number #1/2/5/6/7/8 -> I1 OMC cable side
Serial number #9/10/11/12 -> H1 OMC cavity side |
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Mon Oct 14 13:40:16 2013, Koji, Optics, Characterization, H1 OMC Optical testing
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Since the middle of September, the optical tests of H1 OMC were took place.
Here is summary of the progress.
TEST1: FSR/FINESSE measurement before applying First Contact |
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Mon Oct 14 15:50:55 2013, Koji, Optics, Characterization, H1 OMC Power budget
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LHO OMC power budget
Date
2013/9/17
2013/9/17
2013/10/16
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