40m QIL Cryo_Lab CTN SUS_Lab CAML OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  OMC elog, Page 6 of 13  Not logged in ELOG logo
ID Date Author Typeup Category Subject
  443   Wed Aug 24 03:20:59 2022 KojiGeneralGeneralOMC #002 Delamination repair Part2 (2)


  444   Wed Aug 24 03:26:43 2022 KojiGeneralGeneralOMC #002 Delamination repair Part2 (3)



  445   Wed Aug 24 11:29:47 2022 KojiGeneralGeneralOMC #002 ready for shipment

[Stephen Koji]

The OMC #002 is ready for shipment.

Attachment 1: Work done on Sept 19, 2022

Other attachments: Putting the OMC in the pelican case.

  446   Thu Aug 25 14:22:08 2022 KojiGeneralGeneralLLO OMC #001 Ballast Mass investigation

Inspected the past LLO add-on mass configuration.

There are unknown masses at the DCPD side. It looks like a small SS mass with an estimated mass of 5g. But the DCC number is unknown.

We are going to add 10g on each corner as well as the damping aterial. We should be able to figure out the fastener / mass configuration.

  447   Thu Aug 25 20:05:00 2022 KojiGeneralGeneralLLO OMC #001 Ballast Mass investigation

Here is the balance mass info for the LLO OMC#001 analyzed from the photographs

  • Added masses are: 50+10g, 50+20, 10+20+5, and 20+20+10 for the mass right above FM1/CM1/FM2 and CM2, respectively.
  • The length of the 1/4-20 screws seem L=3/4"~1"

If we attach the additional mass, longer 1/4-20 screws (1", 1" 1/8, 1" 1/4) are going to be used.

  448   Fri Aug 26 22:29:02 2022 KojiGeneralGeneralTool Shipping Prep

Shipping preparation for the LLO trip

Started July 15, 2022 and finished Aug 30. So it took ~1.5 months (with a couple weeks of break)

Class B special tools

  • Screw Drivers 1
    • https://www.steritool.com/
    • https://www.steritool.com/precision-screwdrivers-mini.aspx
  • Screw Drivers 2
    • What I have seems S555Z-7
    • https://www.starrett.com/
    • https://www.starrett.com/dms/flipbooks/Cat-33/index.html?page=354
  • Allen Wrenches
    • Bondhus: These are not made of SS, but of so called protanium steel. I have a chrome finish one (BriteGuard) and K14 gold finish one (goldguard).
    • https://intl.bondhus.com/pages/goldguard-ball-end
    • https://intl.bondhus.com/pages/briteguard-ball-end
  • Scissors
    • VWR - Stainless Steel
    • Unknown PN /  probably this?
    • https://us.vwr.com/store/product/4527635/vwr-dissecting-scissors-sharp-blunt-tip
  • Forceps
    • VWR - Stainless Steel
    • https://us.vwr.com/store/product/4531765/vwr-hemostatic-forceps
  • Wire cutters
    • Looks like they are orthodontic wire cutters. One has the marking "Orthomechanic Stainless Steel" but the company does not sell cutters anymore. The other has a marking "333" but the company is unknown. Similar products can be found on Amazon
  • Long nose pliers - straight stainless steel
    • https://www.aventools.com/
    • https://www.aventools.com/long-nose-pliers-stainless-steel-6-2
  • Bent nose pliers - stainless steel
    • unknown 
  • Tweezers
    • Excelta 
    • The short one is 20A-S-SE. The longer one is 24-SA-PI, maybe?
    • https://www.excelta.com/
    • https://www.excelta.com/straight-laboratory-instruments-forceps
    • https://www.excelta.com/style-24-24-6-sa
  • Mighty-Mouse spanner
  • 2x driver bits for the digital torque wrench

First Contact Kit

  • FC bottole / PEEK mesh

Bonding kit (excl EP30-2 bond)

  • reinforcement bars (4 types)
  • bonding liner powder
  • tools: spatula / bond applying rod

Power meters (excl Power meter controller)

  • Thorlabs Thermal
  • Thorlabs Photodiode
  • Thorlabs Integrating Sphere


  • preamp + power cable
  • PD testing kit (PD connector / DB9 break out / grabber-BNC)
  • Nitrile gloves

Cable bracket replacement kit

  • PEEK cable bracket (Helicoiled)
  • Cable pegs (x4 salvaged / spare)
  • fastners
  • kapton sheet
  • cable ties

Optics / Optomechanics

  • Optical fiber / spare fiber
  • OMC transport feet
  • OMC backscatter inspection prisms

Misc tools

  • digital torque wrench

=== Action done on Aug 30 ===

Fiber MM setup / Fiber coupler mount
Glass Beamdumps (for optical testing)
Flipper mirror
Thorlabs fiber coupler tool
General bent nose plier for fiber
Thorlabs collimator tiny allen
Spare High QE PDs

Spare OMC bags / Zip bags

Balance Mass 10g Qty 8 (Different Type D11*** 1.25" dia), 20g Qty 10 / Mass damper D1700301 -04 / Mass damper screws SHCS 1/4-20 x 1.25 Qty 25 / 1" screws and 1 1/8" screws

Shipping request: https://services1.ligo-la.caltech.edu/FRS/show_bug.cgi?id=25002

=== Low supply! ===

  • Masks
  • 7.0 gloves supply low
  • 7.5 glove completely gone
  • Wet vectra cloth
  • Dry vectra cloth
  449   Tue Sep 20 08:54:33 2022 KojiGeneralGeneralPD cage arrangement

Upon the LLO work, the current PD arrangement in the cages are:
B1 OMC1 PDT (A1-23)
B2 OMC1 PDR (A1-25)
B3 original (C1-03)
B4 OMC2 PDT (B1-22)

C1 OMC2 PDR (B1-23)
C2 original (C1-08)
C3 original (C1-09)
C4 original (C1-10)

  450   Mon Sep 26 14:27:49 2022 KojiGeneralGeneralLLO OMC ICS work

OMC #001

OMC #002

  461   Fri Nov 18 18:41:05 2022 Camille MakaremGeneralGeneral2nd deep cleaning of OMC #1

The four cavity mirrors in OMC #1 were each scrubbed using acetone and a cotton swab.
Then, the four mirrors were painted with First Contact (picture attached). The First Contact was allowed to dry for 20 minutes, then removed while using the top gun.

  462   Mon Nov 21 19:13:35 2022 KojiGeneralGeneralTransmission measurement (2nd deep cleaning of OMC #1)

OMC Transmission measurement after the 2nd deep cleaning

The 2nd deep cleaning didn't improve the transmission. (See Attachment 2)
The measured loss was 0.044+/-0.002


  463   Tue Nov 29 15:54:47 2022 KojiGeneralConfigurationWindows laptop for WincamD Beam'R2 recovery

Aaron took the set to Cryo lab


  473   Wed Jan 25 23:51:04 2023 KojiGeneralGeneralThe items packed for Downs

Qty1 1/2 mounts
Qty2 prism mounts
Qty6 gluing fixures
Qty1 Rotary stage
Qty1 2" AL mirror
Qty1 Base for the AL mirror

=> Handed to Stephen -> Camille on Jan 27, 2023.

  482   Wed Feb 1 01:44:14 2023 KojiGeneralGeneralOMC (004) plan

2/1 2:30PM~ Bonding reinforcement (Last EP30-2 gluing)

2/2 1:00PM~ Peripheral attachment / Optical testing setup

  487   Sat Feb 4 03:33:22 2023 KojiGeneralGeneralOMC Lab Inventory

Attachment 1: North Cabinet 2nd from the left

Attachment 2: North Cabinet 3rd from the left

Attachment 3: South Cabinet (right)

  525   Tue Apr 18 07:59:46 2023 Madeline LesovskyGeneralGeneralTest Cure Bake - Curved Mirror Subassembly Bonding

This is a test bake conducted in Air Bake Oven A (ABO-A) held in the 40m Clean and Bake facility. The overall objective is to sucessfully cure the Curved Mirror Subassemblies with the appropriate temperature profile. In this test run, we wanted to ensure that the temperature profile dictated via the Platinum software is stable and repeatable.

Specific curing instructions can be found in LIGO-E1300201-v1, section 6.2.4 (https://dcc.ligo.org/E1300201-v1). This test air bake load contained several stainless steel masses and a stainless steel tray that will be utilized in the production curing run. Note that the thermacouple has been placed between two stainless steel masses.

Temperature profile results from 4/14/23 test cure can be seen in attachments below.


  529   Wed Apr 26 14:43:44 2023 StephenGeneralLoan / LendingBorrowed Items for PZT DC Response Shadow Sensor Setup

Borrowed for PZT DC Response Shadow Sensor Setup (see Attachment 1):

  • Thorlabs PDA100A Photodiode (and power supply)
  • Thorlabs MDT694B Piezo Driver

Current Location: Downs 227

  535   Thu May 4 15:12:14 2023 KojiGeneralCharacterizationOMC (004): Final Testing
  • 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 shim height adjustment
  • QPD alignment / shim height adjustment
  • Alignment: beam spot photos
  537   Thu May 11 10:46:17 2023 Thejas GeneralCharacterizationaLIGO OMC

[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. 

  538   Fri May 12 10:00:06 2023 Camille MakaremGeneralLoan / LendingBorrowed Items for PZT DC Response Shadow Sensor Setup

The ThorLabs MDT694B piezo driver was returned to the OMC lab.


Borrowed for PZT DC Response Shadow Sensor Setup (see Attachment 1):

  • Thorlabs PDA100A Photodiode (and power supply)
  • Thorlabs MDT694B Piezo Driver

Current Location: Downs 227


  541   Tue May 16 10:26:12 2023 KojiGeneralCharacterizationOMC (004): Final Testing
  • 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 shim height adjustment
  • QPD alignment / shim height adjustment
  • Alignment: beam spot photos


The OMC PZT ac response was resorded was not as expected and a remeasurement will be attempted this week. Data: https://www.dropbox.com/s/7pf0k6awoa4wg0z/230503.zip?dl=0 





  • 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
  • DCPD shim height adjustment
  • QPD alignment / shim height adjustment
  • Alignment: beam spot photos


  543   Fri May 19 16:09:31 2023 StephenGeneralGeneralA+ OMC Build Progress, Week of 2023.05.15

A+ OMC Build efforts ongoing or completed this week:

  •  PZT lead onboard strain relief (D2000172)
    • Brief discussion in A+ SUS call - PEEK material callout is to be updated in v2, Don is handling this.
    • v1 drawings posted and UK team out for production, with Angus already communicating PEEK grade requirement to vendor during procurement process.
    • DCN is WIP per Russell.
  • Rework of Helicoil holes
    • D1201278 and D1300498 were already Class A, but we recognized that the hole callouts were not consistent with current LIGO notation, and we decided to make sure that these holes were in a good state.
    • Don and I chased the holes with taps (gloves on, but in a dirty area)
    • Don created a C&B Ticket request/1835
  • PZT characterization (ref. T1500060-v2 - PZT Testing Section 2.3.2)
    • DC Response measurement - see OMC_Lab/542 for initial findings.
      • 11 units appear to be good, 2 units appear to be damaged, 5 units need to be recharacterized (after soldering rework).
      • Quantitative results WIP.
    • Lab move to Downs 320 - this work needs to be logged.
      • DC Response setup updated, beam focusing was changed.
      • Oplev setup for Length to Angle measurement constructed for the first time.
  • Component matching for Curved Mirror Subassembly
    • Continued work on algorithm-based matching code
    • Discussion with Gari and Calum - we will move toward manual matching to expedite

We have the following plans for the week ahead:

  • Complete PZT DC Response data analysis.
  • Finish solder rework of PZT leads.
  • Start PZT Length to Angle measurement.
  • Manually match Curved Mirror Subassembly components, enough to bond first 4 assemblies.
    • (this will be pending full characterization of PZTs)
  • Make sure clean and bake ticket gets processed for reworked parts mentioned above.

We have the following near future plans:

  • Start PZT reliability testing (burn-in test) (ref. T1500060-v2 - PZT Testing Section 2.3.4),
    • Focused on units that will be used to bond first 4
  • Bond first batch of Curved Mirror Subassemblies.
    • Make sure we have enough EP30-2 for subsequent batches (some used by HoQi effort)..
  • Resume transport fixture build effort at 40m Bake Lab.
  • Conduct walkthrough of OMC lab with build in mind.
  • Follow updates of top level assy D2000172, and send finalized assy for 3D printing of mockup unit.
  546   Fri Jun 2 17:15:44 2023 StephenGeneralGeneralA+ OMC Build Progress, Weeks of 2023.05.22 and 2023.05.29

A+ OMC Build efforts ongoing or completed in the last two weeks:

  •  PZT lead onboard strain relief (D2000172)
    • Some more discussion in A+ SUS calls - PEEK material callout is to be updated in v2, Don is handling this.
    • Looking forward to timeline update in coming week
  • Rework of Helicoil holes
    • Don's C&B Ticket is being processed by Maty, will go for bake next week - request/1835
  • PZT characterization (ref. T1500060-v2 - PZT Testing Section 2.3.2)
    • DC Response measurement - no new data collection.
      • 5 articles need to be recharacterized (after soldering rework).
      • Code for quantitative results is 90% complete, still debugging (WIP).
    • Lab move to Downs 320 - updated setup logged in OMC_Lab/545.
      • DC Response setup has not been rebuilt yet, but will need to be for more testing after solder repairs and/or reliability testing.
      • Oplev setup for Length to Angle measurement is operational.
    • Length to Angle measurement - lots of setup, refinement, and growing pains toward data collection.
      • 11 PZTs measured, just like DC Response (5 articles requiring solder rework)
  • Component matching for Curved Mirror Subassembly
    • Matching calculations first draft (implemented manually) was supplied by Thejas.
    • EP30-2 batch (2x 50mL syringes) arrived, plenty for all curved mirror subassembly bonding and first OMC unit bonding, at least.

We have the following plans for the week ahead:

  • Complete PZT DC Response and Length to Angle data analysis. (WIP)
    • We have been making manual comparisons / data quality checks throughout data collection.
    • Comparisons with past results from aLIGO build have suggested that our results are reasonable.
  • Finish solder rework of PZT leads. (had been planned, solder hasn't arrived yet)
  • Set up shadow sensor in new lab for future DC Response measurements.
  • Set up PZT reliability testing (burn-in test). (ref. T1500060-v2 - PZT Testing Section 2.3.4)
  • Resume transport fixture build effort at 40m Bake Lab.
    • Summer student Maria will be heavily involved.
  • Insert helicoils in Class A plasma-sprayed DCPD housings

We have the following near future plans:

  • Bond first batch of Curved Mirror Subassemblies.
  • Conduct walkthrough of OMC lab with build in mind.
    • Transport Class A components that are ready for build to OMC cleanroom.
  • Follow updates of top level assy D2000172, and send finalized assy for 3D printing of mockup unit.
    • Make sure that strain relief components are all on order and we know the timeline.

  549   Sun Jun 25 21:04:35 2023 KojiGeneralCharacterizationOptical assembly/testing of OMC (004) completed

Optical assembly/testing of OMC (004) completed
- OMC (004) with the transport fixture was wrapped and moved to Downs 227 together with the boxes for OMC cabling hardware and DCPD/QPD connector parts.
- The table was cleared for building the O5 OMCs.

  550   Sun Jun 25 21:08:37 2023 KojiGeneralCharacterizationOMC (004) transported to Downs for cable furnishing

OMC (004) + the transport fixture was transported to Downs 227 with the boxes for OMC cabling hardware and DCPD/QPD connector parts.

  553   Thu Jul 6 10:19:23 2023 Thejas GeneralCharacterizationOMC Lab optic table

[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 mirror was mounted to redirect the beam. Next step: Cavity assembly 

  557   Mon Jul 10 20:29:05 2023 Koji GeneralCharacterizationOMC(004) PZT characterization

Belated entry: OMC(004) PZT Slow scan / freq response measurements (May 10/11/17, 2023)

PZT DC scan measurement showed that CM1 had a significantly larger response than the usual PZT responses, and CM2 has the one significantly less. The measurements were repeated and the same result was confirmed.

 Curiously enough, the AC response didn't show a significant difference between the two PZT responses.
Further investigation showed that CM2 shows a similar response to CM1 at low voltage, but has a reduction of the response at high V (like >100V).

So there is something strange with CM2.

Meanwhile, CM1 actuation shows much larger angular coupling and also increased cavity loss.
Therefore, CM1 should be used for the shutter function, and CM2 for the OMC servo.

  559   Wed Jul 12 17:27:44 2023 KojiGeneralGeneralMitsutoyo Digital Caliper (100mm)

We had missing digital caliper from the clean room. As it is an essential component, I have ordered a replacement.

  582   Mon Jul 31 13:19:14 2023 Camille MakaremGeneralGeneralplans for this week 31 July 2023

Plans for this week:
1) Verify electronics setup for cavity locking.
     Current state: Output from function generator is going directly to laser driver (not currently using the Newport Servo Module). We will need to set up the servo module.

2) Finish setting up the table optics so we can monitor the reflected beam (need to set up photodiode and CCD camera to monitor this beam).

3) Once the cavity is locked, we can use the steering mirrors to optimize the cavity while monitoring the CCD cameras for the transmitted and reflected beams. We need to walk the beam so that more of the TEM00 mode is transmitted. (Currently still seeing a lot of higher order modes transmitted, as shown in attachment).

  583   Tue Aug 1 11:04:13 2023 Camille MakaremGeneralGeneralreoptimizing cavity alignment before locking

[Camille, Thejas]
We rechecked the alignment this morning and re-optimized the resonance a bit. There was some horizontal drift in the alignment from yesterday.

Plan for this afternoon:
Camille, Thejas, and Masayuki will meet with Koji in the OMC lab to go over electronics setup. (Need to set up EOM driver? Laser is not sweeping.)

  585   Thu Aug 3 07:22:19 2023 Camille MakaremGeneralGeneralparticle count and cavity optimization/alignment

Yesterday, we measured the particle count in the enclosure to ensure that the lower setting on one of the HEPAs is still acceptable. The particle count is still zero for all measured particle sizes (0.3um, 0.5um, 1.0um, 2.0um, and 5.0um).

We also relocked the cavity and repeated the optimization efforts in https://nodus.ligo.caltech.edu:8081/OMC_Lab/584. The reflected signal was around 110mV (compared to 80mV on Tuesday).

We used a CCD camera to view the beam spots on the curved mirrors (pictures attached). We will compare the spot positions to the scatter plots for these mirrors and try to steer the beam spots accordingly.
(*Note: We did see some stray light scattering on the edge of FM2. We will further examine this and see where the stray light is coming from.)


  588   Thu Aug 3 15:04:26 2023 StephenGeneralGeneralaLIGO Unit 4 Build, Cable Routing, Preparation

[Dean, Stephen]

Unit #4 aLIGO OMC unit was transported to the 40m Bake Lab.

We unwrapped the Transport Fixture and identified the orientation which would place the Light Side up and accessible. We removed the 4 long SHCS (Dark Side up), then rolled the Transport Fixture to the Light Side Up orientation. The PEEK pads were kept in the locked state, with set screws pushed forward. We loosened the set screws, retracted the PEEK pads, lifted the transport fixture lid, and saw no issues with the breadboard. While rotating the Transport Fixture, Stephen had allowed the Transport Fixture to tilt down a little bit harder than intended.

We noticed the oxidation of the PZT lead which had happened during acetone debonding (OMC_Lab/378).

We opened and inspected the Class A bulkhead 4-pin male Mighty Mouse connectors (Glenair p/n 803-003-07M6-4SN-598A) from Bake-7594. There are quantity 13 in the bag, with approximately the right amount of pins. We also opened and inspected the PEEK cable ties, aluminum Cable Pegs D1300057-v2, and additional button head screws for cable pegs (Koji had considerately installed some, while waiting for the Cable Pegs).

Dean added, to the PZT leads, the pins for Mighty Mouse connectors using a wiped-down crimper. He then bundled the PZT leads and routed the PZT wire bundles to Dark Side of the breadboard.

Koji supplied us with the on-board DCPD and QPD cables, and we anticipate that he will bring the DCPDs when we install the on-board cables. We are ready to install the on-board cables and complete Dark Side cable routing, and we will coordinate a work session with Koji.

Photos are posted to this Google Photos album: aLIGO Unit 4 Build, Cable Routing - https://photos.app.goo.gl/LAJ1Q6Fw9X8TrUBu6

  591   Mon Aug 7 07:36:09 2023 Camille MakaremGeneralGeneralparticle count

[Camille, Thejas]

We lowered the setting to MEDIUM on the HEPA furthest from the entrance. (The two HEPA settings are now LOW and MEDIUM.) We measured the particle count for all particle sizes at different locations in the enclosure (next to the OMC fixture and at the edge of the table closest to the entrance). All counts read zero.

  595   Mon Aug 7 16:00:30 2023 KojiGeneralGeneralOMC (004): Cable installation

The writing of this elog is still on going

[Dean, Stephen, Koji]

4th OMC production was completed.

Today's Menu

  • PZT connector assembly
  • DCPD/QPD cable installation to the DCPD/QPD housings
  • Cable installation on the connector harness
  • Routing of the cables / Installation of the cable ties
  • Storage

== PZT connector assembly ==

Dean and Stephen already crimped the pins to the PZT wires in the previous session.
We wanted to complete this cable by inserting the pins into the mighty mouse connector

This MM connector has the pin1 at the top left and numbered clock wise when it is seen from the mating side with the center notch up. 

We looked at D1300589. This drawing has some inconsistency in the description (LV Piezo at the left side turns to HV Piezo at the right side), but it is not an issue as we are supposed to have two identical (or similar) PZTs.

Here the arrangement of the MM connectors:
- Pin 1:  PZT1 Pos
- Pin 2:  PZT1 Neg
- Pin 3:  PZT2 Pos
- Pin 4:  PZT2 Neg

== DCPD/QPD cable installation to the DCPD/QPD housings ==

We opened the cable bags and found that they were not completed. The cables didn't have face parts. We found the face parts in the cable parts plastic box, but the screws were missing. We had to send one to pick up screws from the OMC lab while the others were working on inserting helicoils into the cable ASSYs.

We also found the ancient elog about the cables. This told us that the cable set we had was not the proper one, but rather spares with all the long variants of the cables. This meant that the routing needed to be different from the past 3 OMCs.

The flex PCB boards have solder bumps sticking out. This prevented the front pieces from being flush with the back piece. It was slightly improved by clipping a few solder marks (Attachments 1/2). The cables were inserted into the DCPD/QPD housings. To align the connector heads properly, we installed dummy (i.e., non-high-QE PDs with caps) PDs to the housing. The QPDs were necessary to be removed from the housing as it was known that the insertion was very difficult.

DCPD cable for DCPD1 (Trans side): D1300372 S1301809
DCPD cable for DCPD2 (Refl side): D1300372 S1301807

QPD cable for QPD1 (Refl side): D1300375 S1301816
QPD cable for QPD2 (Trans side): D1300375 S1301814

Cable installation on the connector harness

We flipped the OMC (manually) so that we could work on the suspension side. The connectors were attached to the cable harness. The connector nuts were fastened by a nut spanner and/or a long-nose plier. (Attachment 3)

Routing of the cables / Installation of the cable ties

As mentioned above, some cables are longer than they used to be. So the routing required some creativity. The cables were attached to the cable pegs. We used Kapton sheets to distribute the cable tie's pressure to the wires and also protect the wires from the ties.


The OMC (004) and the transport fixture were so far placed in the 40m clean room.

  596   Mon Aug 7 16:01:05 2023 KojiGeneralGeneralOMC (004): Production completed

OMC (004) Production completed. The OMC together with the transport fixture is still placed at the 40m clean room.

  615   Tue Aug 22 15:51:15 2023 KojiGeneralGeneralInventory: C30655 PDs

During the OMC(004) assembly, the stock situation for Excelitas C30655 PDs was checked.

PD Cage H
Slot 1: Laser Components 3mm ->
Slot 2: Laser Components 3mm -> one of them is broken
Slot 3: C30655
Slot 4: Empty

PD Cage I
Slot 1: C30655 PD window unopened - Sourced from 40m
Slot 2: C30655 PD window unopened - Sourced from 40m
Slot 3: C30655 PD window unopened - Sourced from 40m
Slot 4: C30655 PD window opened - collected from photon-recycling experiment / state unknown

C30665 #4/#5/#6/#8/#13

- Some of the PDs were still in OMC (004) -> will be used for 40m BHR
- More PDs will be used for 40m BHR

  52   Sun Jan 6 23:22:21 2013 KojiMechanicsGeneralSolidWorks model of the OMC suspension


  58   Tue Jan 22 17:56:32 2013 KojiMechanicsGeneralRotary stage selection

Newport UTR80

Newport 481-A (SELECTED)

  • Sensitivity: 15 arcsec
  • Graduations: 1 deg
  • Vernier: 5 arcmin
  • Fine travel range: 5 deg
  • With Micrometer

Newport RS40

  • Sensitivity: 16 arcsec
  • Graduations: 2 deg
  • Vernier: 12 arcmin
  • Fine travel range: 10 deg
  • Micrometer BM11.5

Newport RS65

  • Sensitivity: 11 arcsec
  • Graduations: 2 deg
  • Vernier: 12 arcmin
  • Fine travel range: 10 deg
  • Micrometer SM-06 to be bought separately

Elliot science MDE282-20G

  • Sensitivity: 5 arcsec
  • Graduations: 2 deg
  • Vernier: 10 arcmin
  • Fine travel range: 10 deg
  • Micrometer 2 arcmin/1div
  • Metric

Suruga precision B43-110N

Thorlabs precision B43-110N

  69   Thu Mar 7 15:53:47 2013 KojiMechanicsGeneralOMC Transportation fixture, OMC PD/QPD mounts






  70   Thu Mar 14 17:06:21 2013 KojiMechanicsGeneralOMC SUS work @LLO

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.

Photos sent from Zach



  90   Mon Apr 1 10:28:03 2013 KojiMechanicsGeneralAdditional UV blast for the top surface

[Koji, Lisa, Jeff, Zach]

Jeffs concern after talking with the glue company (EMI) was that the UV blast for the top side was not enough.

First we wanted to confirm if too much blasting is any harmful for the glue joint.

We took a test joint of FS-FS with the UV epoxy. We blasted the UV for 1min with ~15mm distance from the joint.
After the observation of the joint, we continued to blast more.
In total, we gave additional 5min exposure. No obvious change was found on the joint.


Then proceed to blast the OMC top again. We gave 1 min additional blast on each glue joint.

 P3283459.jpg P3283473.JPG

  92   Wed Apr 3 17:39:38 2013 KojiMechanicsCharacterizationCalibration of the test PZTs before the glue test

We want to make sure the responses of the PZT actuator does not change after the EP30-2 gluing.

A shadow sensor set up was quickly set-up at the fiber output. It turned out the ring PZTs are something really not-so-straightforward.
If the PZT was free or just was loosely attached on a plane by double-sided tape, the actuation response was quite low (30% of the spec).
After some struggle, I reached the conclusion that the PZT deformation is not pure longitudinal but some 3-dimensional, and you need to
use a "sandwitch" with two flat surfaces with some pressue.

I turned the setup for horizontal scans to the vertical one, and put the PZT between quarter-inch spacers.
Then two more spacers are placed on the stack so that the weight applies the vertical pressure on the PZT.
This is also use ful to adjust the height of the shadow.


The calibration plot is attached. It gives us ~21k V/m.
Voltage swing of 150V results the output voltage change of ~50mV.  This is pretty close to what is expected from the spec (16nm/V).
The PZT#3 (which had the mirror glued on) showed significantly large response.

Test PZT #1: 17.4nm/V
Test PZT #2: 17.2nm/V
Test PZT #3: 30.6nm/V
UHV PZT #24: 17.6nm/V

These numbers will be checked after the heat cure of EP30-2

  98   Fri Apr 5 14:39:26 2013 KojiMechanicsCharacterizationCalibration of the test PZTs after the heat cure

We attached fused silica windows on the test PZTs. http://nodus.ligo.caltech.edu:8080/OMC_Lab/93

The glued assemblies were brought to Bob's bake lab for the heat cure. There they are exposed to 94degC heat for two hours (excluding ramp up/down time).

After the heat cure, we made the visual inspection.
The photos are available here.

Test PZT #1: 17.4nm/V
Test PZT #2: 17.2nm/V
Test PZT #3: 30.6nm/V

Test PZT #1: 27.2 nm/V
Test PZT #2: 26.9 nm/V
Test PZT #3: 21.4 nm/V

Measurement precision is ~+/-20%
Spec is 14nm/V

  102   Mon Apr 8 11:49:18 2013 KojiMechanicsCharacterizationPZT actuator tested at LLO

Test result of the PZTs by Valera and Ryan

PZT  Length Angle
 #   [nm/V] [urad/um]
 11  14.5   17.6
 12  13.8   17.8
 13  11.2   25.0
 14  14.5    6.6
 15  12.5   10.6

 21  14.5    9.7
 22  13.8   28.8
 23  14.5    6.8  ==> Assembly #2
 24  18.5   51.7  ==> Used for prototyping
 25  17.1   13.8
 26  14.5    6.6  ==> Assembly #1
  124   Mon May 13 14:49:35 2013 KojiMechanicsCharacterizationMounting Glass Bracket still broke with tightenin stress

[Koji / Jeff]

This is the elog about the work on May 9th.

We made two glass brackets glue on the junk 2" mirrors with the UV glue a while ago when we used the UV bonding last time.

On May 7th:

We applied EP30-2 to the glass brackets and glued invar shims on them. These test pieces were left untouched for the night
and brought to Bob for heat curing at 94degC for two hours.

On May 9th:

We received the test pieces from Bob.

First, a DCPD mount was attached on one of the test pieces. The fasteners were screwed at the torque of 4 inch lb.
It looked very sturdy and Jeff applied lateral force to break it. It got broken at once side of the bracket.

We also attached the DCPD mount to the other piece. This time we heard cracking sound at 2 inch lb.
We found that the bracket got cracked at around the holes. As the glass is not directly stressed by the screws
we don't understand the mechanism of the failure.

After talking to PeterF and Dennis, we decided to continue to follow the original plan: glue the invar shims to the brackets.

We need to limit the fastening torque to 2 inch lb.

  125   Mon May 13 14:59:16 2013 KojiMechanicsGeneralInvar shim gluing

The invar reinforcement shims were glued on the glass brackets on the breadboard.
We worked on the light side on May 10th and did on the dark side on May 13rd.

U-shaped holding pieces are used to prevent each invar shim to be slipped from the right place.

We are going to bring the OMC breadboard to the bake oven tomorrow to cure the epoxies and promote the outgasing.

  130   Thu May 23 23:41:48 2013 KojiMechanicsGeneralDCPD/QPD Mount

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)

Face plates fatsened by 4-40x5/16 BHCS (24 out of 40)

Housing   Face plate Destination  PD
002       002        L1OMC DCPD1  #10
003       003        L1OMC DCPD2  #11
       004        H1OMC DCPD1
       005        H1OMC DCPD2
       006        I1OMC DCPD1
       007        I1OMC DCPD2

QPD (mounting 4-40x5/16 BHCS Qty4)

Face plates fatsened by 4-40x1/4 BHCS (24 out of 80)

Housing   Face plate Destination QPD
002       002        L1OMC QPD1  #38 #43 swapped on 29th May.
003       003
        L1OMC QPD2  #43 #38 swapped on 29th May.
       004        H1OMC QPD1
      005        H1OMC QPD2
      006        I1OMC QPD1
      007        I1OMC QPD2

* 4-40x5/16 BHCS Qty 8 left
* 4-40x5/16 BHCS Qty 56 left

Cut the diode legs by 3mm


  148   Sat Jul 6 17:10:07 2013 KojiMechanicsCharacterizationPZT Response analysis

Analysis of the PZT scan / TF data taken on May 31st and Jun 1st.

[DC scan]

Each PZT was shaken with 10Vpp 1Hz triangular voltage to the thorlabs amp.
The amp gain was x15. Abut 4 TEM00 peaks were seen on a sweep between 0 and 10V.

The input voltage where the peaks were seen was marked. Each peak was mapped on the
corresponding fringe among four. Then the each slope (up and down) was fitted by a iiner slope.
Of course, the PZTs show hystersis. Therefore the result is only an approximation.

PZT1: PZT #26, Mirror C6 (CM1)
PZT2: PZT #23, Mirror C5 (CM2)

PZT arrangement [ELOG Entry]

Ramp Up        13.21nm/V
Ramp Down   13.25nm/V
Ramp Up        13.23nm/V
Ramp Down   13.29nm/V

=> 13.24+/-0.02 nm/V

Ramp Up        13.27nm/V
Ramp Down   12.94nm/V
Ramp Up        12.67nm/V
Ramp Down   12.82nm/V

=> 12.9+/-0.1 nm/V

[AC scan]

The OMC cavity was locked with the fast laser actuation. Each PZT was shaken with a FFT analyzer for transfer function measurments.
(No bias voltage was given)

The displacement data was readout from the laser fast feedback. Since the UGF of the control was above 30kHz, the data was
valid at least up to 30kHz. The over all calibration of the each curve was adjusted so that it agrees with the DC response of the PZTs (as shown above).

The response is pretty similar for these two PZTs. The first series resonance is seen at 10kHz. It is fairly high Q (~30).

  158   Tue Aug 27 17:02:31 2013 KojiMechanicsCharacterizationSpot position measurement on the diode mounts

After the PZT test, the curved mirrors were aligned to the cavity again.

In order to check the height of the cavity beam, the test DCPD mount was assembled with 2mm shim (D1201467-3)
The spot position was checked with a CCD camera.

According to the analysis of the picture, the spot height is about 0.71mm lower than the center of the mount.

  160   Thu Aug 29 18:55:36 2013 KojiMechanicsGeneralI1 OMC top side gluing (UV)

The glass components for the I1 OMC top side were glued by the UV glue.

Breadboard SN#4
Wire bracket SN#5/6/7/8

  202   Tue Jul 8 18:54:54 2014 KojiMechanicsCharacterizationPZT characterization

Each PZT was swept with 0-150V 11Hz triangular wave.
Time series data for 0.2sec was recorded for each PZT.

The swept voltage at the resonances were extracted and the fringe number was counted.
Some hysteresis is seen as usual.

The upward/downward slopes are fitted by a linear line.

The average displacement is 11.3nm/V for PZT1 and 12.7nm/V.

The PZT response was measured with a FFT analyzer. The DC calibration was adjusted by the above numbers.

ELOG V3.1.3-