40m QIL Cryo_Lab CTN SUS_Lab CAML OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  OMC elog, Page 2 of 11  Not logged in ELOG logo
ID Date Author Typeup Category Subject
  303   Thu Jul 26 20:57:07 2018 KojiElectronicsCharacterization9MHz port tuned impedance

[Rich Koji]

The 9MHz port was tuned and the impedance was measured.

  304   Tue Aug 7 15:43:12 2018 KojiElectronicsCharacterizationNew LLO EOM stuffed

[Rich, Dean, Koji]

Stuffed all inductors for the new LLO EOM. As the impedances were sensitive to the positions of the inductors in the housing, they were glued with a glue gun.
Also the lid of the housing significantly change the stray capacitance and lowers the resonant frequency (meaning lowers the Q too), we decided to tune the matching circuit without the lid.

The attached plots show the measured impedances. They all look well tuned and matched. We will prepare and perform the optical measurement at the 40m.

  385   Tue Oct 22 15:54:59 2019 KojiElectronicsLoan / LendingBorrowed LB1005 from Cryo Cav

From Cryo Cav setup

Borrowed LB1005 Servo box -> OMC

 

  402   Sat Nov 21 13:58:30 2020 KojiElectronicsCharacterizationDark Current Measurement for InGaAs QPDs

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 the diode cans.

Overall, the QPDs nominally indicated the usual dark current level of <10nA.
SEG1 of #82 showed a lower voltage of reverse breakdown but this is not a critical level.
#83 showed variations between the segments compared to the uniform characteristics of #81 and #84.

  403   Sun Nov 22 13:49:12 2020 KojiElectronicsCharacterizationImpedance Measurement for InGaAs QPDs

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:
The impedance of a device can be measured, for example, from the complex reflection coefficient (S11). To measure the reflection, a bidirectional coupler was brought from the 40m. Attachments 1 and 2 shows the connection. The quantity A/R shows S11. The network analyzer can convert a raw transfer function to an impedance in Ohm.

Calibration and Measurement limit:
The network analyzer was calibrated with 1) a piece of wire to short the clips 2) 50ohm resistor 3) open clips. Then the setup was tested with these three conditions (again). Attachment 3 shows the result. Because of the impedance variation of the system (mainly from the Pomona clip, I guess), there looks the systematic measurement error of ~1pF or ~25nH. Above 100MHz, the effect of the stray impedance is large such that the measurement is not reliable.

The setup was tested with a 10pF ceramic capacitor and this indicated it is accurate at this level. The setup is sufficient for measuring the diode junction capacitance of 300~500pF.

Impedance of the QPD segments:

Then the impedances of the QPD segments were measured (Attachment 4). The segments showed the identical capacitance of 300~400pF level, except for the variation of the stray inductance at high freq, which we can ignore. Note that there is no bias voltage applied and the nominal capacitance in the datasheet is 225pF at 5V reverse bias. So I can conclude that the QPDs are quite nominal in terms of the junction capacitance.

(Ed: 11/23/2020 The RF components were returned to the 40m)

  404   Mon Nov 23 23:17:19 2020 KojiElectronicsCharacterizationThe dark noise of the Q3000 QPDs

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.

The measured floor level of the dark current was below the shot noise level for the DC current of 0.1mA (i.e. 6pA/rtHz).
No anomalous behavior was found with the QPDs.

Note that there is a difference in the level of the power line noise between the QPDs. The large part of the line noises was due to the noise coupling from a soldering iron right next to the measurement setup, although the switch of the iron was off. I've noticed this noise during the measurement sets for QPD #83. Then the iron was disconnected from the AC tap.
 

  405   Tue Nov 24 10:45:07 2020 gautamElectronicsCharacterizationThe dark noise of the Q3000 QPDs

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.

Quote:

The measured floor level of the dark current was below the shot noise level for the DC current of 0.1mA (i.e. 6pA/rtHz).

  406   Tue Nov 24 12:27:18 2020 KojiElectronicsCharacterizationThe dark noise of the Q3000 QPDs

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.

  486   Sat Feb 4 03:30:02 2023 KojiElectronicsGeneralOMC cables #4 arrived

The OMC cables #4 arrived on Feb 3rd. (See Attachment)

This shipment included two DCPD cables and two QPD cables. It means that the direct wiring from the PZT to the mighty mouse connectors was not included in the shipment.

  493   Wed Feb 15 16:00:46 2023 StephenElectronicsGeneralOMC cables #4 inspected

Inspection

Updated ICS (Shipment-12578) and moved those parts to Storage-9482.

Inspection showed the following:

  • Serial numbers matched the packing list
  • SN S1301807: We observed some discoloration on the Gore wire close to one cable termination. [Attachment 1]
    • greenish tint
    • appeared to be superficial
    • slight removal observed when gently wiped with an IPA soaked AlphaWipe ("red wipe")
    • did not follow the helical of the teflon sheath
    • recommend additional inspection when Unit 4 build is resumed
  • Cables were returned to the box labeled "OMC Cables" in the south cabinets in the OMC lab.

Observations for aLIGO OMC Unit 4 Build

An ICS Record Navigator search of onboard OMC cables reveals the following quantities appear to have been fabricated for aLIGO.

  • D1300371 = Qty 3
  • D1300372 = Qty 5
  • D1300374 = Qty 3
  • D1300375 = Qty 5

The leftover cables are all of the long variety (D1300372, D1300375), and the received quantities make sense. 3 aLIGO OMC assemblies used quantity 3 of each cable, leaving the remaining cables which had been stored at LHO:

  • D1300372 = Qty 2
  • D1300375 = Qty 2

The received cables from LHO may apparently be used interchangably, and the extra slack (~ 5", compared to the D1300371, D1300374 part numbers) should be managable.

Next Steps for aLIGO OMC Unit 4 Build

We will move forward in fabricating Unit 4 with the received cables from LHO, despite their extra length.

To complete the Unit 4 on board cable set (refer to OMC_Lab/203), we will need to crimp pins onto the PZT leads, and we need to find, clean, and bake quantity 1 4 pin mighty mouse connector.

  • PZT leads terminate crimp pins inserted into Glenair Mighty Mouse 803-003-07M6-4PN-598A (per OMC_LAB/203, record navigator)
  • Cable bracket interface to OMCS is Glenair Mighty Mouse 803-003-07M6-4PN-598A (per D1300376-v3).

I will ask Chub to see if there are any Class A spares of the PZT termination connector already on hand.

  497   Fri Feb 17 17:41:57 2023 Thejas ElectronicsCharacterizationA+ OMC Piezos wedge angle

[Camille, Stephen, Thejas]

PZT model: Noliac 2124

Qty: 18 (Sr. No. 30 - 48)

Today, PZT dimensions were measured. Inner radius of the ring and thickness at different points can be used to determine the wedge angle and direction of the PZTs. This is essential for evaluation of appropriate combination of subassembly (curved mirror + PZT + Hole prism) prior to bonding them. 

 

  544   Tue May 23 16:30:09 2023 Thejas ElectronicsCharacterizationA+ OMC Piezos LA coupling

Oplev setup was built: arm length about 2 m 

As the PZT 44 was actuated with a drive voltage 0-150 V signal was observed on the Spectrum Analyser.

The signal on the top and bottom are X and Y signals from the QPD. This will analyzed and other PZTs will undergo similar measurement. 

  545   Fri Jun 2 13:28:09 2023 Camille MakaremElectronics PZT op-lev measurements

The op-lev setup was modified slightly (picture attached). The He-Ne laser was replaced with one with a lower divergence angle. The stage that the PZT/mirror stack sits on was replaced with a setup that allows for tip/tilt adjustements. The PZTs were driven from 0 to ~92V at 0.5Hz. The total path length from the PZT stack to the QPD is ~1.6m.
The following PZTs have been measured in the current oplev setup: 37, 38, 39, 40, 41, 42, 43, 44, 46, 47, 48.

 

  3   Wed Jun 20 00:10:53 2012 KojiFacilityGeneralHole on the wall was patched

P6191706.jpg

  14   Wed Aug 1 19:35:00 2012 KojiFacilityGeneralFloor cleaned / Workbench being built / Table top defect

- The floor of the room was cleaned and waxed!

- Sticky mats are placed! Now we require shoe covers!

P8011949.JPG

- Work benches are being built. One unit is done.

P8011948.JPG

- The other is half done because the table top has chippings.

P8011947.JPG

  15   Sat Aug 11 00:59:14 2012 KojiFacilityGeneralLaser Safety Barrier

It seemed that a laser safety barrier was installed today!?

P8131960.JPG

 

  19   Wed Aug 22 20:16:43 2012 KojiFacilityGeneralWorkbenches have been installed / Clean room stools

Last Friday, new workbenches were installed. Vladimir got a new table and a cleanroom stool.

P8171968.jpg

The other two workbenches were also nicely set.

P8171969.jpg

  46   Wed Dec 26 14:33:33 2012 KojiFacilityGeneralLase Interlock wired

Two switches are connected in series.

  57   Tue Jan 22 11:10:25 2013 KojiFacilityGeneralEyeware storage and hooks for the face shields are installed

A carpenter has come to install the eyeware storage and hooks for the face shields.

  75   Sat Mar 23 02:32:23 2013 KojiFacilityGeneralN2 cylinder delivered

Preparation for ionized N2 blow

- 99.9998% N2 cylinder delivered (ALPHAGAZ 2 grade by AIR LIQUIDE) ALPHAGAZ 2 [PDF]

- Filter and Arcing module already in the lab

- A brass regulator to be installed (Done - March 24)

- 50 ft air line already in the lab / needs to be wiped/rinsed (Done - March 24)

- Air line and filter installed (Done - March 24)

  288   Fri Sep 8 15:14:05 2017 KojiFacilityGeneralPreparation for the plumbing work

[Steve, Aaron, Koji]

We've finished the preparation for the forthcoming plumbing work on (nominally) Sept 16th Saturday.
We've covered most of the west side of the OMC lab with plastic sheets and wraps.

Some tips:

  • The plastic sheets Eric gave us were a bit too thin and pron to got torn. Thicker sheets are preferable.
  • The blue tape that Eric gave us was very useful.
  • The stretch wrap film, which I bought long time ago, was so useful. Office Depot "Office Depot(R) Brand Stretch Wrap Film, 20 x 1000 Roll, Clear" PN: 445013
  • We also used patches of Kitchen Trash Bags to cover some small opening of the large sheets. Office Depot "Glad(R) Tall Kitchen Trash Bags, 13 Gallon, White, Box Of 28" PN 269268
  391   Mon Aug 10 15:34:04 2020 KojiFacilityLoan / LendingGlue bake oven

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.

  412   Thu Jun 23 21:03:33 2022 KojiFacilityGeneralMoving the small optical table to CAML (TCS Lab)

I've cleared the small optical table and wondered how to move it out of the room. Fortunately, the north side of the big table had wide enough clearance and let the 36" wide table go through. This was easy without moving other heavy stuff.

From here to the door, a bit of work is required. A possibility is to roll the laser blocking wall to the south side of the big table. This will require moving the shelving in the entrance area but it's not a lot of work compared to disassembling a part of the wall.

If this does not work somehow, we will consider removing the last panel of the wall and it will definitely allow the table to get out from the door.

  485   Sat Feb 4 03:22:46 2023 KojiFacilityGeneralReady for the HEPA enclosure expansion

HEPA is quite low for a tall person and also the curtain on the back of us is always heavy. It's very tough for anyone to work with. (See Attachment 1)

I did the lab and table organization so that the HEPA expansion work can be resumed.
The 4th OMC is still on the table with the transport fixture (See attachment 3), but it is secured on the table. The risk of damaging the OMC is low now.

Chub can start working on the HEPA. Occasionally Camille and Thejas may work on the optical setup with the OMC. It is fine as long as both happen at the same time.

  500   Mon Mar 6 12:25:08 2023 KojiFacilityGeneralHEPA Enclosure improvement

Chub, JC, and co worked on the HEPA enclosure improvement.

  519   Wed Apr 5 22:09:30 2023 KojiFacilityGeneralHEPA Enclosure extension

Chub finished the HEPA enclosure extension project.

  1   Fri Jun 15 15:45:49 2012 KojiGeneralGeneralOMC Plan

LIGO Document G1200683-v1:
aLIGO OMC fabrication and testing plan

aLIGO OMC wiki

  2   Sat Jun 16 08:53:09 2012 KojiGeneralGeneralTo Do List

Facility

Mechanics

  • Work 
    •  
  • Design
    • How do we hold the PDs, QPDs, and black glass - we put 2 PDs and 2 QPDs on the PD mounting blacket.
    •  
  •  
  • Test
     
  • Things to be tested
    • New suspension scheme (cup & cone design)
    • Balancing the plates
    • Dummy metal payload?
  • => Suspending test with a suspension cage for a Faraday isolator@CIT
    • Supporting block for the suspension cage (to mimic the OMC suspension)
  • Things to be designed
    • Wire end (cone)
    • Diode holding structures
      PD/QPD/PZT holding structure
  • PZT alignment
  • Prototyping with metal parts?
  • UV glue? (heat) / gluing test
  • Balance / ballast
     
  • Solid works

Optics

  • Mirrors to be delivered ~Aug
  • Design down select
    • Between "Single output & BS" vs "Two outputs & no BS"
  • Mode design
  • Finalization of scattering paths / PD angles etc
     
  • Things to be decided / confirmed:
    • How to handle optics / assemblies (Talk to the prev people)
    • First contact? (Margot: applicable to a short Rc of ~2.5m)
    • Gluing templates to be designed (how to handle it?)
  • Things to be tested:
    • R&T of each mirror
    • Cavity ref/trans/finesse
    • PD QE / incident angle
       
  • What PD do we use?
     
  • CCD beam analyzer (Zach: It is fixed.)
     
  • PD angle measurement
  • Obtain EG&G 3mm PDs

Electronics

  • Electronics / CDS electronics / software
     
  • Things to be tested
    • QPD/PD pre-selections (QE/noise)
    • Functionality test of QPD/PD/PZT

Shipping, storage etc


Jun/July
    - Lab renovtion
    - Mechanics design
    - Glue training
Aug
    - Mirror delivery
    - Basic optics test
Sept
    - Cavity test
    - Suspending test
NOV~DEC
    - Shipping to LLO

Open questions
    Two optical designs
    Procedure
    Modeling
    Clamp design / stencil design
    gluing-installation procedure

  7   Sat Jul 14 02:16:07 2012 KojiGeneralGeneralPlan Update: July

Facility/Supplies

  • Work in progress
    • Floor cleaning
    • Plug slits on the roof of the HEPA booth - blanking panels have been ordered (Peter)
    • Install laser safety barrier (Peter is working on this)
    • Place a sticky mat
       
  • Work to be done
    • Replacing a file cabinet next to the south wall by a lockable cabinet
    • Replacing a lab desk at the west side of the room. (Vladimir's)
    • Replacing Vladimir's rack with nicer one.
    • Laser sign
    • Safety glass holder
    • Prepare clean supplies (Shoes/Coverall/Hats/Gloves) => go to VWR stock room
      • glove 8.5,9,9.5
         
    • Label maker (P-Touch) & Tape
        
  • Design
    • Optical layout - Laser SOP
    • Additional HEPA stage
       
  • Test
    • Confirm particle level
       
  • Note: Optical Table W96" x D48" x H27"

Beaurocracy

  • Laser SOP
  • HV use?
  • UV?

Mechanics

  • Ongoing Work 
    • Cone-shaped wire clamp design (at the OMC end) - Jeff
       
  • Design
    • Wire preparation fixture - Jeff
    • How do we hold the PDs, QPDs, and black glass - we put 2 PDs and 2 QPDs on the PD mounting blacket. - Jeff
    • Integrated solidwork model - Sam
      • Q: How the wires are clamped at the top side?
      • Q: How much the length of the wire should be?
      • Q: Locations of the wire mounts on the plate
    • Cabling investigation:
      • Where do the cables from the feed-thrus anchored? - Sam
      • List of the current internal cables and their lengths - Sam
      • List of the required internal cables and their lengths
      • Can we route the intermediate stage of the suspension? Do we need new cables?
    • Dummy intermediate stage structure
       
    • Metal templates
      • First, decide an optical design
      • takes at least a month
         
    • Weights how heavy / how many
       
  • Test
    • Cone-shaped wire clamp test - Jeff/Koji 
    • Balancing the plates
      • The Faraday isolator cage isn't clean
    • Dummy metal payload test at the sites???
       
  • Procedures to be decided
    • PZT alignment
    • Prototyping with metal parts?
    • UV glue? (heat) / gluing test
    • Balance

Optics

  • Ongoing Work 
    • Mirrors to be delivered ~Aug
       
    • Design down select - Between "Single output & BS" vs "Two outputs & no BS"
    • Down selecting procedure:
      1. Assume ELIGO beam component
      2. Assume amount of 9MHz / 45MHz sidebands at the OMC input
      3. Calculate transmitted power
      4. Require HOM to be smaller than the TEM00 offset 
         
    • UV cured epoxy (Quate obtained)
  • Design
    • Mode design for HAM6 layout
    • Finalization of scattering paths
       
  • Tests
    • Measurement of PD angles
    • R&T of each mirror
    • Curvature of the curved mirrors
    • Cavity ref/trans/finesse
    • PD Q.E. & Reflectivity measurement vs incident angle
       
  • Things to be decided / confirmed
    • How to handle optics / assemblies (Talk to the prev people)
    • First contact? (Margot: applicable to a short Rc of ~2.5m)
    • Gluing templates to be designed (how to handle it?)
       
  • PDs
  • Misc
    • CCD beam analyzer (Zach: It is fixed.)
    • Are two PZTs used?
      • YES, for redundancy, range, upconversion tests.
         
  • Things to buy
  • Need to buy a fiber for mode cleaning?
  • Mode content of the ELIGO dark beam?
  • Jitter noise?
  • How to determine the design?
  • Why Fused Silica? (How much is the temp fluctuation in the chamber?)
  • How to align the cavity mirrors, input mirrors, QPDs, PDs, beam dumps.
     

Electronics

  • Thorough scrutinization of cabling / wiring / electronics
  • Electronics / CDS electronics / software
  • Things to be tested
    • QPD/PD pre-selections (QE/noise)
    • Functionality test of QPD/PD/PZT

Shipping, storage etc


Jun/July
    - Lab renovtion
    - Mechanics design
    - Glue training
Aug
    - Mirror delivery
    - Basic optics test
Sept
    - Cavity test
    - Suspending test
NOV~DEC
    - Shipping to LLO

Open questions
    Two optical designs
    Procedure
    Modeling
    Clamp design / stencil design
    gluing-installation procedure

 


July:Facility/Supplies

  11   Tue Jul 24 11:41:29 2012 KojiGeneralGeneralUseful references

Nicolas Smith,
LIGO Document T0900383-v1
3mm Photodiode Characterization for Enhanced LIGO
https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=4498

Tobin Fricke,
LIGO Document P1000010-v1
Homodyne detection for laser-interferometric gravitational wave detectors
https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=8443

Nicolas Smith,
LIGO Document P1200052-v1
Techniques for Improving the Readout Sensitivity of Gravitational Wave Antennae
https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=90498

  12   Tue Jul 31 21:29:43 2012 KojiGeneralGeneralWork completed in July [!]

 

  13   Tue Jul 31 21:33:17 2012 KojiGeneralGeneralPlan Update: August [!]

Completed work of the previous months: [Jul] [Aug] [Sep] [Oct] [Nov] [Dec]


Facility/Supplies

  • Work done
  • Things ordered
    • Office Depot
      • [delivered] Office Depot(R) Brand Stretch Wrap Film, 20 x 1000 Roll, Clear / 445013
      • [delivered] Eveready(R) Gold AA Alkaline Batteries, Pack Of 24 / 158448
      • [delivered] Rubbermaid(R) Roller Sponge Mop / 921841
      • [delivered] Rubbermaid(R) Roller Sponge Mop Replacement / 921858
      • [delivered] Rubbermaid(R) Sanitizing Caddy, 10 Quarts, Yellow / 674125
      • [delivered] Glad(R) Tall Kitchen Trash Bags, 13 Gallon, White, Box Of 28 / 269268
    • Global Industrial Equipment
      • [delivered] Extended Surface Pleated Cartridge Filter Serva-Cell Mp4 Slmp295 12X24X2 Gl    WBB431699
    • Global Industrial Equipment
      • [delivered] Nexel Poly-Z-Brite Wire Shelving 30"W x 21"D x 63"H Nexel Poly-Z-Brite™ Wire Shelving Starter Unit WB189209
      • [delivered] Stem Casters Set of (4) 5" Polyurethane Wheel, 2 With Brakes 1200 lb. Capacity WB500592    
    • Rack Solutions
      • [delivered] Open Frame Server Racks
        1 x 20" Depth Kit (Ideal for Audio/Video or Networking Racks) P/N: 111-1779
        1 x 36U, Rack-111 Post Kit P/N: 111-1728
        1 x Caster Kit for Open Frame RACK-111 P/N: 111-1731
      • [delivered] 36U Side Panel Kit $199.99 P/N: 102-1775
    • Rack shelf
      • [delivered] 1 RMS 19 X 15 SINGLE SIDED NON-VENTED SHELF 70121637
    • Work bench, Stools
      • [not yet] 72"L X 30"W Production Bench - Phenolic Resin Square Edge-Blue Form attached WB237381LBL    
      • [not yet] 72"W Lower Shelf For Bench - 15"D- Blue Form attached WB606951    
      • [not yet] ESD-Safe Vinyl Clean Room Stool with Nylon Base with Drag Chain Blue Form attached WBB560852    
    • P Touch
      • [delivered] Brother PT-2030 Desktop Office Labeler Punch-out product 672828    
      • [delivered] Brother(R) TZe-241 Black-On-White Tape, 0.75 x 26.2 Punch-out product 239384    
      • [delivered] Brother(R) TZe-231 Black-On-White Tape, 0.5 x 26.2 Punch-out product 239400    
    • UV light guide
      • [delivered] Fiber Optic Single Light Guide 5mm OD X 3mm ID X 1M L Note: This light guide can be used with MKIII UV Cure unit. OLB1081
    • Gloves (7.5, 8.0)
      • [delivered] GLOVE ACCTCH NR-LTX SZ7.5 PK25 Punch-out product 79999-306
      • [delivered] GLOVE ACCTCH NR-LTX SZ8 PK25 Punch-out product 79999-308
    • Lab coat (L,XL), Sticky Mat, Shoe Covers (L, XL), Cap, Mask
      • [delivered] LAB XP WH EL WR.COLL. NP L30EA Punch-out product 82007-618
      • [delivered] LAB XPWH EL WR.COLL. NP XL30EA Punch-out product 82007-620    
      • [delivered] VWR MAT ADHESIVE 30L 18X36 BLU Punch-out product 21924-110 (This was too small)
      • [delivered] VWR SHOECVR NSKID AP 2XL 150PR Punch-out product 414004-651    
      • [delivered] VWR SHOECVR NSKID AP XL 150PR Punch-out product 414004-650    
      • [delivered] CAP BOUFFANT 24IN RAYON CS500 Punch-out product 10843-053    
      • [delivered] MASK VLTC TIES N/STRL PK50 Punch-out product 10869-020
    • VWR
      • [delivered] FACE SHIELD UVC-803 Supplier: UVP 33007-151
         
    • [Delivered] Laser safety glasses
  • Work in progress

    •  
  • Work to be done
    • Replacing a file cabinet next to the south wall by a lockable cabinet
    • Laser sign
    • Safety glass holder/rack/shelf
    • Prepare clean supplies ~ glove 8.5,9,9.5
    • Ion gun safety issues: https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=88631
        
  • Design
    • Optical layout - Laser SOP
    • Additional HEPA stage
       
  • Test
    • Confirm particle level
       
  • Note: Optical Table W96" x D48" x H27"

Beaurocracy

  • Laser SOP
  • HV use?
  • UV?

Mechanics

  • Ongoing Work 
    • Cone-shaped wire clamp design (at the OMC end) - Jeff
       
  • Design
    • Wire preparation fixture - Jeff
    • How do we hold the PDs, QPDs, and black glass - we put 2 PDs and 2 QPDs on the PD mounting blacket. - Jeff
    • Integrated solidwork model - Derek
      • Q: How the wires are clamped at the top side?
      • Q: How much the length of the wire should be?
      • Q: Locations of the wire mounts on the plate
    • Cabling investigation:
      • Where do the cables from the feed-thrus anchored?
      • List of the current internal cables and their lengths
      • List of the required internal cables and their lengths
      • Can we route the intermediate stage of the suspension? Do we need new cables?
    • Dummy intermediate stage structure
       
    • Metal templates
      • First, decide an optical design
      • takes at least a month
         
    • Weights how heavy / how many
       
    • Earthquake stop design (Sam B)
       
  • Test
    • Cone-shaped wire clamp test - Jeff/Koji 
    • Balancing the plates
      • The Faraday isolator cage isn't clean
    • Dummy metal payload test at the sites???
       
  • Procedures to be decided
    • PZT alignment
    • Prototyping with metal parts?
    • UV glue? (heat) / gluing test
    • Balance

Optics

  • Things ordered
    • Newport LB servo
    • Halogen Lamp
    • N2 cylinder/lines/filter
  • Ongoing Work 
    • Mirrors to be delivered ~Aug
       
    • Design down select - Between "Single output & BS" vs "Two outputs & no BS"
    • Down selecting procedure:
      1. Assume ELIGO beam component
      2. Assume amount of 9MHz / 45MHz sidebands at the OMC input
      3. Calculate transmitted power
      4. Require HOM to be smaller than the TEM00 offset 
         
    • UV cured epoxy (Quate obtained)
  • Design
    • Mode design for HAM6 layout
    • Finalization of scattering paths
       
  • Tests
    • Measurement of PD angles
    • R&T of each mirror
    • Curvature of the curved mirrors
    • Cavity ref/trans/finesse
    • PD Q.E. & Reflectivity measurement vs incident angle
       
  • Things to be decided / confirmed
    • How to handle optics / assemblies (Talk to the prev people)
    • First contact? (Margot: applicable to a short Rc of ~2.5m)
    • Gluing templates to be designed (how to handle it?)
       
  • PDs
  • Misc
    • CCD beam analyzer (Zach: It is fixed.)
    • Are two PZTs used?
      • YES, for redundancy, range, upconversion tests.
         
  • Things to buy
  • Need to buy a fiber for mode cleaning?
  • Mode content of the ELIGO dark beam?
  • Jitter noise?
  • How to determine the design?
  • Why Fused Silica? (How much is the temp fluctuation in the chamber?)
  • How to align the cavity mirrors, input mirrors, QPDs, PDs, beam dumps.
  • PZTs @LLO
     

Electronics

  • Thorough scrutinization of cabling / wiring / electronics
    • ELIGO OMC Wiring diagram D070536-A2
      • Occupies 2 DB25s -> They were anchored on the sus cage
      • Preamps for DCPDs will be fixed on the ISI table
        -> DB25 for the DCPDs will be anchored on the table
      • Use longer thin cables for the DCPDs in order to route them through the suspension stages
      • Turn the heater cable to the one for the other PZT
  • Electronics / CDS electronics / software
  • Things to be tested
    • QPD/PD pre-selections (QE/noise)
    • PD preamp design (Rich)
    • Functionality test of QPD/PD/PZT

Shipping, storage etc


Jun/July
    - Lab renovation
Aug

    - Mechanics design
    - Mirror delivery
Sept

    - Basic optics test
    - Glue training
Oct
    - Cavity test
Nov

    - Suspending test
Dec
    - Shipping to LLO

Open questions
    Two optical designs
    Procedure
    Modeling
    Clamp design / stencil design
    gluing-installation procedure

  27   Tue Oct 16 14:50:54 2012 jamie, jeffGeneralGeneralOMC breadboard/plate measurement dimensions

We have measured the dimensions and mass of the OMC glass plates/breadboards:

S/N Mass (g) Length (mm) Width (mm) Height (mm) Notes
01 6146 449.66 149.85 41.42, 41.42  for LLO
02 6126 449.66 149.97 41.32, 41.32  for LHO
03 6143 449.76 149.98 41.39, 41.43  
04 6139 449.78 149.81 41.40, 41.40  for 3IFO
05 6132 449.76 150.03 41.27, 41.31 corner chip, front-bottom-left*
06 6138 449.84 149.71 41.42, 41.42  
  • * orientation is relative to "front" face, i.e. long-short face with S/N on it, with S/N upright.
  • Height measurements were made twice, once at each end.
  • TMeasurements of 03, 05, 02, and 06 were done in the open in the OMC lab.  This was not thought to be too much of an issue since the plates
    are already covered with particulate matter from the tissue paper that they were wrapped in. 
    Measurements of 04 and 01 were done on the optics table, under the clean room enclosure.

Note by Koji:

  • The scale of the bake lab was used. (Max 60kg, Min resolution of 1g)
  • The dimensions were measured by a huge caliper which Jeff brought from Downs.
  • S/N 01, 03, 04 look pretty similar. They should be the primary candidates.
  28   Tue Oct 16 15:50:09 2012 KojiGeneralGeneralWork completed in August/September [!]
  • Work done
  • Things ordered
    • Office Depot
      • [delivered] Office Depot(R) Brand Stretch Wrap Film, 20 x 1000 Roll, Clear / 445013
      • [delivered] Eveready(R) Gold AA Alkaline Batteries, Pack Of 24 / 158448
      • [delivered] Rubbermaid(R) Roller Sponge Mop / 921841
      • [delivered] Rubbermaid(R) Roller Sponge Mop Replacement / 921858
      • [delivered] Rubbermaid(R) Sanitizing Caddy, 10 Quarts, Yellow / 674125
      • [delivered] Glad(R) Tall Kitchen Trash Bags, 13 Gallon, White, Box Of 28 / 269268
    • Global Industrial Equipment
      • [delivered] Extended Surface Pleated Cartridge Filter Serva-Cell Mp4 Slmp295 12X24X2 Gl    WBB431699
    • Global Industrial Equipment
      • [delivered] Nexel Poly-Z-Brite Wire Shelving 30"W x 21"D x 63"H Nexel Poly-Z-Brite™ Wire Shelving Starter Unit WB189209
      • [delivered] Stem Casters Set of (4) 5" Polyurethane Wheel, 2 With Brakes 1200 lb. Capacity WB500592    
    • Rack Solutions
      • [delivered] Open Frame Server Racks
        1 x 20" Depth Kit (Ideal for Audio/Video or Networking Racks) P/N: 111-1779
        1 x 36U, Rack-111 Post Kit P/N: 111-1728
        1 x Caster Kit for Open Frame RACK-111 P/N: 111-1731
      • [delivered] 36U Side Panel Kit $199.99 P/N: 102-1775
    • Rack shelf
      • [delivered] 1 RMS 19 X 15 SINGLE SIDED NON-VENTED SHELF 70121637
    • Work bench, Stools
      • [not yet] 72"L X 30"W Production Bench - Phenolic Resin Square Edge-Blue Form attached WB237381LBL    
      • [not yet] 72"W Lower Shelf For Bench - 15"D- Blue Form attached WB606951    
      • [not yet] ESD-Safe Vinyl Clean Room Stool with Nylon Base with Drag Chain Blue Form attached WBB560852    
    • P Touch
      • [delivered] Brother PT-2030 Desktop Office Labeler Punch-out product 672828    
      • [delivered] Brother(R) TZe-241 Black-On-White Tape, 0.75 x 26.2 Punch-out product 239384    
      • [delivered] Brother(R) TZe-231 Black-On-White Tape, 0.5 x 26.2 Punch-out product 239400    
    • UV light guide
      • [delivered] Fiber Optic Single Light Guide 5mm OD X 3mm ID X 1M L Note: This light guide can be used with MKIII UV Cure unit. OLB1081
    • Gloves (7.5, 8.0)
      • [delivered] GLOVE ACCTCH NR-LTX SZ7.5 PK25 Punch-out product 79999-306
      • [delivered] GLOVE ACCTCH NR-LTX SZ8 PK25 Punch-out product 79999-308
    • Lab coat (L,XL), Sticky Mat, Shoe Covers (L, XL), Cap, Mask
      • [delivered] LAB XP WH EL WR.COLL. NP L30EA Punch-out product 82007-618
      • [delivered] LAB XPWH EL WR.COLL. NP XL30EA Punch-out product 82007-620    
      • [delivered] VWR MAT ADHESIVE 30L 18X36 BLU Punch-out product 21924-110 (This was too small)
      • [delivered] VWR SHOECVR NSKID AP 2XL 150PR Punch-out product 414004-651    
      • [delivered] VWR SHOECVR NSKID AP XL 150PR Punch-out product 414004-650    
      • [delivered] CAP BOUFFANT 24IN RAYON CS500 Punch-out product 10843-053    
      • [delivered] MASK VLTC TIES N/STRL PK50 Punch-out product 10869-020
    • VWR
      • [delivered] FACE SHIELD UVC-803 Supplier: UVP 33007-151
         
    • [Delivered] Laser safety glasses

 

  29   Tue Oct 16 15:51:01 2012 KojiGeneralGeneralPlan Update: October [!]

Completed work of the previous months: [Jul] [Aug] [Sep] [Oct] [Nov] [Dec]


Facility/Supplies

  • Work in progress
    • RoC measurement
    • R&T measurement
    • Wedge measurement
  • Work to be done
    • Replacing a file cabinet next to the south wall by a lockable cabinet
    • Additional clean supplies ~ glove 8.5,9,9.5
    • Stainless bats
    • Ion gun safety issues: https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=88631
        
  • Design
    • Laser SOP
       
  • Test
    • Continuous monitoring of the particle level
       
  • Note: Optical Table W96" x D48" x H27"

Beaurocracy

  • Laser SOP / HV use? / UV?
  • Procedures to be decided
    • PZT alignment
    • UV glue? (heat) / gluing test
    • Balance
    • N2 cylinder/lines/filter
  • Design
    • Mode design for HAM6 layout
    • Finalization of scattering paths
       
  • Things to be decided / confirmed
    • How to handle optics / assemblies (Talk to the prev people)
    • First contact? (Margot: applicable to a short Rc of ~2.5m)
    • Gluing templates to be designed (how to handle it?)
       
  • PDs
  • Things to buy
  • Need to buy a fiber for mode cleaning?
  • Mode content of the ELIGO dark beam?
  • Jitter noise?
  • How to determine the design?
  • Why Fused Silica? (How much is the temp fluctuation in the chamber?)
  • How to align the cavity mirrors, input mirrors, QPDs, PDs, beam dumps.
  • PZTs @LLO
     

Electronics

  • Thorough scrutinization of cabling / wiring / electronics
    • ELIGO OMC Wiring diagram D070536-A2
      • Occupies 2 DB25s -> They were anchored on the sus cage
      • Preamps for DCPDs will be fixed on the ISI table
        -> DB25 for the DCPDs will be anchored on the table
      • Use longer thin cables for the DCPDs in order to route them through the suspension stages
      • Turn the heater cable to the one for the other PZT
  • Electronics / CDS electronics / software
  • Things to be tested
    • QPD/PD pre-selections (QE/noise)
    • PD preamp design (Rich)
    • Functionality test of QPD/PD/PZT

Shipping, storage etc

  33   Wed Nov 7 20:21:42 2012 KojiGeneralGeneralWork completed in October [!]

Completed work of the previous months: [Jul] [Aug] [Sep] [Oct] [Nov] [Dec]


 

  34   Wed Nov 7 20:44:11 2012 KojiGeneralGeneralPlan Update: November [!]

Completed work of the previous months: [Jul] [Aug] [Sep] [Oct] [Nov] [Dec]


  • Work done
    • Wedge measurement (1st trial) [ELOG]
    • RoC measurement [ELOG]
  • Work in progress
    • R&T measurement
    • Wedge measurement
  • Work to be done
    • QPD/PD pre-selections (QE/noise)
    •  
    •  
    •  
    • Misc. / Beaurocracy?
      • Continuous monitoring of the particle level
      • Replacing a file cabinet next to the south wall by a lockable cabinet
      • Ion gun safety issues: https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=88631
      • Laser SOP / HV use? / UV?
  • Things delivered
  • Things ordered
    • Power strips Tripp Lite PS3612 (Ordered Nov. 8, Delivered Nov. 12)
    • Kapton tapes (1in x 6, 1/2in x 12 Delivered Nov. 15)
    • Sticky Mats (VWR 18888-216 Delivered Nov. 12 and 21992-042)
    • Duck tape (PK3) (Delivered Nov. 12)
    • Wipers 12"x12" 2ply x 119 pairs x case15 (Delivered Nov. 12)
    • Syringes (1mL&2mL) & Needles (20G x dozen)
    • Stainless trays with cover (Steve Delivered Nov. 12)
    • Gold Plated allen keys (Steve Delivered Nov. 12)
    • Forceps (Delivered Nov. 12) / Tweezers / Scissors (Delivered Nov. 12)
  • Things to buy / get
    • OMC testing optics / opto-mechanics
    • Black Glass / Black Glass holder / AR ==> Some at the 40m, some from LLO
    • Ionized air blow
      • N2 or Air cylinder: 4N - UHP or 5N - Research Grade.  (... steal from Downs)
    • Clean tools, tray, storage
    • Supply
      • Additional clean supplies ~ glove 8.5,9,9.5
      • Stainless bats / Pure solvents (Metha / Aceton / Iso) / Syringes / Lint free cloth / Paper lens tissue
      • Lab coats
    • ATF
      • Tefron tape
      • Thorlabs 8-32 screw kit / Thorlabs HW-KIT1
      • Pedestal Shims - Newport
  • Things to be done
    • Cavity ref/trans/finesse
    • PD Q.E. & Reflectivity measurement vs incident angle
    • Functionality test of QPD/PD (PeterK) /PZT
       
  • Procedures to be decided
    • PZT alignment
    • UV glue? (heat) / gluing test
    • Balance
    • N2 cylinder/lines/filter
    • Shipping procedure: New shipping cage design on going (Jeff) => Plastic box similar to COC
  • Design
    • Solidworks raytracing model
    • Mode design for HAM6 layout
       
  • Things to be decided / confirmed
    • How to handle optics / assemblies (Talk to the prev people)
    • First contact? (Margot: applicable to a short Rc of ~2.5m)
    • Gluing templates to be designed (how to handle it?)
  • Jitter noise?
  • How to align the cavity mirrors, input mirrors, QPDs, PDs, beam dumps.

Electronics ==> Rich

  47   Mon Dec 31 01:45:04 2012 KojiGeneralGeneralWork completed in Nov and Dec [!]

Completed work of the previous months: [Jul] [Aug] [Sep] [Oct] [Nov] [Dec]


  • Work done
  • Things delivered
    • The ionized gun used in the clean room at Downs: made by Terra Universal.com (Jeff's room)
      http://www.terrauniversal.com/static-control/ionizing-blow-off-guns.php
    • Flow path: N2 cylinder - Filter - Gun (Jeff's room)
    • Power strips Tripp Lite PS3612 (Ordered Nov. 8, Delivered Nov. 12)
    • Kapton tapes (1in x 6, 1/2in x 12 Delivered Nov. 15)
    • Sticky Mats (VWR 18888-216 Delivered Nov. 12 and 21992-042)
    • Duck tape (PK3) (Delivered Nov. 12)
    • Wipers 12"x12" 2ply x 119 pairs x case15 (Delivered Nov. 12)
    • Syringes (1mL&2mL) & Needles (20G x dozen)
    • Stainless trays with cover (Steve Delivered Nov. 12)
    • Gold Plated allen keys (Steve Delivered Nov. 12)
    • Forceps (Delivered Nov. 12) / Tweezers / Scissors (Delivered Nov. 12)
    • OMC testing optics / opto-mechanics
    • SolidWorks raytracing model
    • Mode design for HAM6 layout [Zach]
       
    • Black Glass / Black Glass holder / AR ==> Some at the 40m, some from LLO
    • Ionized air blow
      • N2 or Air cylinder: 4N - UHP or 5N - Research Grade.  (... steal from Downs)
  61   Thu Feb 7 21:35:46 2013 KojiGeneralGeneralDmass's loan of LB1005 / A2&C2 sent to Fullerton / First Contact @40m

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.

First Contact kit (incl. Peek Sheets)
Manasa borrowed the kit on Feb 7.
Got it back to the lab.

  71   Thu Mar 14 22:18:23 2013 KojiGeneralGeneralNew loans for the diode test

ALL returned

Loan from ATF:

2 blue banana cables returned on Jun 4, 2013

BNC cable returned on Mar 21, 2013

TENMA triple power supply returned on July 17, 2015

From 40m:

4x GPIB cables returned on Mar 21, 2013

From EE shop:

red banana cables returned on Jun 4, 2013

  79   Mon Mar 25 02:04:05 2013 KojiGeneralGeneralOMC building plan / procedure ~ WB18

WB 18 March

  • Diode test
    • Dark current / Dark noise / Impedance
    • Quantum Efficiency test (but with glass)
    • Diode given to Bob for cleaning
  • Research possible issue of UV light on 1064 HR coating
    • ~ppm order loss increase after depositing 3J/cm^2 in 8 hours (i.e. same order to our illumination but in 10s for us)
    • Sent an e-mail to Ke-Xun Sun -> So far, no reply.
  • Glue test of PZT+prism+curved mirror with UV bond epoxy 
    • Done. Found some handling issues on the fixture.
  • Preparation of N2 line:
    • Done

Action items:

  • Bake test at 100°C for 1 hour at CIT 
    • Will be done on 25 Mon-26 Tue at Bob's lab
  • Curved mirror characterization
  • R&T measurement
  80   Mon Mar 25 18:34:25 2013 KojiGeneralGeneralOMC building plan / procedure ~ Mar 25 Mon

25 March (Mon):

Inspect the test PZT assembly

  • => Give it to Bob. (done)

Glue topside components (done)

  • Clean up the table for the gluing work.
  • Prepare the transport fixture on the table.
  • Glass breadboard
    • Pick breadboard #1 (cf. [ELOG 27])
    • Wipe the entire glass breadboard with IPA
    • Place the breadboard in the fixture (check which is the upper side)
  • Gluing
    • Set the gluing template on the breadboard.
    • Place all of the glass components on the plate (just for confirmation)
    • Wipe (locally) both surfaces to be glued.
    • Apply glue on the component to be glued
    • Align the components in the template. Use the cantilever pusher if necessary.
    • Illuminate UV
    • Repeat the above process for all of the components.
  • Close the transport fixture and wrap with Al foil
  82   Tue Mar 26 22:33:07 2013 KojiGeneralGeneralLoan for the OMC building

Loan from PSL Lab

- 300mm mirror with Ultima mount and pedestal
- Isopropanol small glass bottleReturned on Apr 12 2013.
- Newport 422-1S single-axis stage
Returned on Apr 12 2013.

Loan from ATF Lab

- 50/50 Cube BS 05BC16NP.9 without mount
- 1.5" pedestal (1/4-20 thread), 1/4" shim (1/4-20 through-hole), 1/8" shim (1/4-20 through-hole): 2 eachReturned on Aug 22, 2013.
- PBS & PBS mount
- Newport 422-1S single-axis stageReturned on Apr 12 2013.
- 10 ft BNC cable x 2
- some more BNC (labeled as ATF)Returned on May 20 2013.
- Y1-1037-45P with ultima mount 3inch post
- 1x Newfocus 5104 mirrorReturned on Aug 22, 2013.
- 4x ForkReturned on Aug 22, 2013.

Loan from 40m

- 4 BNC Ts and 1 BNC Ys
- 4 BNC Ts and 1 BNC YsReturned on May 20 2013.
- 6 BNC cablesReturned on May 20 2013.

- SONY CCD / CCD Monitor / CCD power supply
- Optical fiber tester (for fiber alignment) Returned on Apr 9 2013.

  83   Wed Mar 27 20:54:45 2013 KojiGeneralGeneralOMC building plan / procedure ~ Mar 26 Mon

26 March (Tue):

- Curved mirror characterization (Koji, done)

- Input optics for the cavity locking (Zach)

Faraday, BB EOM, Resonant EOM, AOM, MZ

  84   Wed Mar 27 20:54:54 2013 KojiGeneralGeneralOMC building plan / procedure ~ Mar 27 Wed

27 March (Wed)

- AOM drift investigation (Lisa, Zach)

- Cavity input optics ~ Fiber coupling (Zach)

Action Items

  • Glue curved mirror sub-assys.
  • R&T measurement
  85   Wed Mar 27 20:55:10 2013 KojiGeneralGeneralOMC building plan / procedure ~ Mar 28 Thu

28 March (Thu):

  • Rebuild the bottom template in the lab
  • Place the bottom template on the OMC
  • Glue the PZTs on the mounting prisms (x2)
  • Glue the curved mirrors on the PZTs (x2)
  • R&T measurement
  • Placing optics on the OMC breadboard
     
  • Better coupling to the fiber
  • Matching to the OMC cavity

 

29 March (Fri):

Start gluing bottom side: Set 4 cavity mirrors and 1 HR mirror
   and try to resonate beam.  Glue when OK.


Place BS and DCPD mounting brackets.  Glue when OK.
Friday: Place QPDs and rest of optics.  Glue when OK.

WB 1 April

  • Testing at CIT
    • Transmission / Coupling / Loss
    • FSR / TMS
    • Power dependence
    • PZT position dependence
    • Back scattering
    • Openloop TF
    • PZT TF
    • Noise measurement
  • Epoxy cure bake at CIT
  • Retest at CIT
    • ditto

WB 8 April or after

  • Packing
  • Shipping - Shipping box?
  • Optical Testing at LLO (2 days anticipated)
  108   Thu Apr 11 15:10:22 2013 KojiGeneralGeneralOMC Progress

[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
curved mirrors are 6mm in the model. He added 0.3mmx2 to the dimensions.

- Jeff located the template on the breadboard such that each side has
the same amount of hanging out.

- Micrometer values

  • The one closest to the input mirror (CM1) 0.07
  • The other one on CM1 0.24
  • The one closest to the output mirror (CM2) 0.17
  • The other one on CM2 0.30
/------------\

0.17         0.07
\------------/
0.30         0.24

- Now the template is ready to accept the OMC optics.

 


- Zach and Koji finished a series of measurements for the test OMC.

Modulation depth:

- We scanned the laser PZT and recorded the data.
CH1: Reflection DC
CH2: PDH Error
CH3: Transmission (Magnified)
CH4: Transmission

- We should be able to obtain the estimation of the modulation depth and the finesse from this measurement.

- Rough calculation of the modulation depth is 0.19

Transmission:

- Incident 16.3mW
- Transmission 15.1mW
- This gave us the raw transmission of 92.6%ish.
- The modulation depth of 0.19 corresponds to 1.8% of the incident power
- The carrier reflection is almost dominated by the mode mismatch. (Note: We did not have a good resolution for the refl beam)  =>3.2%

- In total:The incident useful carrier power was 15.4mW ==> Throughput 98%
- There is slight headroom to increase the transmission by cleaning the mirrors.

FSR/Finesse:

- As our AOM is not functioning now, phase modulation sidebands are injected with the BBEOM.
- In principle, we can't expect any signal at the transmission at around the FSR frequency.
- If we apply small locking offset, the split peaks appear at the FSR frequency. The frequency of the dip corresponds to the FSR.
- We probably can extract the finesse of the cavity from this measurement. Lisa is working on this.

HOM/Finesse:

- The same PM injection gives us the frequency of the HOMs.
- We found that our EOM can work until ~500MHz.
- We could characterize the cavity resonance structure more than a single FSR.

  116   Thu Apr 18 11:43:59 2013 KojiGeneralGeneralMounting Glass Bracket Failure

[Jeff, Koji]

- While we were working on the optics alignment, one of the mounting brackets made of glass god tore apart into two when a holding screw was removed.
The glass component had a crack at the very middle of the part.

- We borrowed a setup for photoelastisity measurement from Garilynn. This is a set of polarizer configured to have cross polarization. If there is no photoerastisity
the image is colored in blue (somehow). When the polarization is rotated, the color is changed in red, yellow, or white.

- The cross polarizer was tested with a polycarbonate face shield for the UV protection. It seems doing its job.

- We took a set of photos to see any residual stress in a block. The entire inside of the channel is frosted glass so the technique didn't yield much.
In one orientation we did see stress near the ends but the orientation didn't allow us to see exactly where.

- We had 30 brackets and one OMC requires ten of them. This means that there was no spare and now we don't have enough.
  So we decided to spend more as test pieces.

- We tested three scenarios this afternoon. In all three cases both screws were snugged (estimate 0.5 in*lb) before torquing by a torque wrench with a dial meter.
  The divisions on the dial of the wrench are 1 in*lb. We were not so confident in the exact measurement but we felt good about the repeatability of the values.

  1. Duplicated the original mounting with the chamfers of the PEEK bar facing into the channel. Cracked as the torque wrench read 1 in*lb.
      Crack initiation at the first screw, starting along the longitudinal centerline.

  2. Turned the nut bar over so the flat side faced into the channel. Successfully torqued both screws to 1 in*lb and removed them.

  3. With a razor blade, made fairly large reliefs (countersinks) around the holes in the PEEK. Successfully torqued both screws first to 1 in*lb then 1.5 in*lb.
      The block did crack (again at the screw along the centerline) when the torque was ~1.9 in*lb.

It occurs to us that we need micro-compliance AND structural rigidity to distribute the load. The PEEK bars are small and particularly thin where the #4-40 helicoil holes are.
The load is probably concentrated way too much at the holes because it is too weak. Perhaps a good solution, among others, would be to use an aluminum nut plate
with a thin (.02") kapton or viton layer to give the micro-compliance. Additionally, a kapton layer could be used between the block and the aluminum shim,
though this one is probably to be avoided so as to ensure rigidity of the bolted assembly to the bench. Lastly, the nut bar should be shaped such that the area
around the holes and the end of the channel (pretty much the same area) are less stressed than the center portion. 


After the discussion with Peter and Dennis, we decided to reinforce the bonded glass piece with invar shims.
Each shim will be threaded such that we don't need to stress the glass piece any more. EP30-2 will be used as the glue.

  118   Thu Apr 18 11:59:02 2013 KojiGeneralGeneralDCPD path gluing

[Jeff, Koji]

DCPD path gluing

Usual preparation

- Locked the cavity.

- Aligned the input beam to the cavity

DCPD BS gluing

- Placed the DCPD BS on the breadboard

- Placed the dummy DCPD mount on the reflection side of the BS. Check the height and position of the spot.

- Placed the dummy DCPD mount on the transmission side of the BS. Check the height and position of the spot.

- The spot positions looked fine.

- Added a dub of UV glue on the BS. Placed it along the fixture.

- Checked the reflection spot again with the CCD. Kept monitored the spot position through out the gluing process
of the BS.

- Blasted the UV illumination

Reflection side beam dump gluing

- Replaced the alignment disk of the dummy DCPD with a photodiode with the cap removed.

- Put the dummy DCPD mount and the beam dump in place

- Checked the reflection spot from the diode on the beam dump. It looked fine.

- Applied 2~3 dubs of the glue on the beam dump. Slid in the dump to the fixture.

- Applied UV illumination. As the beam dump shadows the illumination 3 times of 10sec blasts were applied.

Transmission side beam dump gluing

- Put the dummy DCPD mount with the diode in place

- Put the beam dump in place. The template needed to be lifted up a bit to accomplish this action.
This should be fixed by the modification of the template.

- Checked the transmission spot on the diode and the spot reflected from the diode on the beam dump.

- Actually the spot was too much close to the vertex of the "V" on the beam dump. We determined that
this was mainly caused by the misalignment of the diode element, and can be compensated by the tilt of the diode mount.

- Removed the beam dump from the template once. Applied 2~3 dubs of the glue on the beam dump.
Slid in the dump to the fixture by lifting up the template again.

- Applied UV illumination. As the beam dump shadows the illumination 3 times of 10sec blasts were applied.

Mounting bracket gluing

- Glued the mounting brackets for the DCPD mounts based on the positions specified by the template.

Removing the templates

- Removed the connection bars between the two templates.

- Removed the template at the QPD side. The screws at all of the three sides were needed to be released in order to accomplish this action.
Once the screws are released, the template was slid on the breadboard so that the pads did not scratch the optical surface.
Keep one side of the template use as a pivot, lifted up another side until the pads clear the optic. Then lifted up the other side.

- Removed the other template. This time, the screws at the two DCPD sides are released. The template was slid and lifted in a same way.

Last beam dump gluing

- Once the QPD side template was removed, the last beam dump at the transmission side of the first steering mirror was glued.

- This has been done without any gluing fixture, we held the beam dump with clean Allen keys on the breadboard.

- The paths for the main and stray beams were confirmed by an IR sensor card, and blasted the UV.

Closing the transport fixture

- Removed the constraining pins for the breadboard.

- Made sure all of the constraining pins/screws are released for the other side of the transport fixture were released.

- Put the lid on.

- Fastened the constraining pins/screws of the transport fixture.

- Wrapped the fixture with sheets of the Al foil.

- Pack the fixture in anti-static bags.

  119   Fri May 3 21:09:08 2013 KojiGeneralGeneralOMC is back

L1 OMC is back on the table for the action next week.

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