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ID Datedown Author Type Category Subject
  467   Mon Dec 5 20:09:39 2022 KojiOpticsGeneral(re)starting the OMC #4 build

[Camille Koji]

We started buikding the OMC #4.

  • Removed OMC #1 from the optical setup and placed it at a safe side on the optical table/
  • Fixed OMC #4 in the optical setup
  • Cleaned the OMC cavity mirrors
  • Placed the OMC cavity mirrors
    • FM1: A1
    • FM2: A3
    • CM1: PZT #11
    • CM2: PZT #12
  • Aligned the beam to the cavity
  • Locked the cavity on TEM00
  • Finely aligned the beam to the cavity
  466   Fri Dec 2 23:58:33 2022 KojiOpticsCharacterizationOMC #1 cleaning for water soluble contaminants

The second trial of the water scrub

A bright scatter is visible on FM1, so I tried water scrub on FM1. This time, both surfaces of FM1 and both surfaces of BS1 were cleaned.

Smaller Vectra swabs were used for the scrub. Then the water was purged by IPA splashed from a syringe. Right after that FC was applied.
This was a bit messy process as the mixture of water/IPA/FC was splattered on the breadboard.
Nevertheless, all the mess was cleaned by FC in the end.

The transmission measurements are shown in Attachment 1, and the analyzed result is shown together with the past results.

The 2nd water scrub didn't improve the transmission and it is equivalent to the one after the two times of deep cleaning.
I concluded that the water scrub didn't change the transmission much (or at all). We reached the cleaning limit.

  465   Fri Dec 2 12:38:15 2022 KojiOpticsCharacterizationOMC #1 cleaning for water soluble contaminants

Another set of FC cleaning was applied to FM1/FM2/CM1/CM2 and SM2. Some FC strings are visible on SM2. So I decided to clean SM2 as well as the cavity mirrors close to SM2 (i.e. FM2 and CM2)

As a result, the bright scattering spot on CM1 is now very dim. And the loss was reduced to 4.0%. This is 0.4% better than the value before the water cleaning.

It'd be interesting to repeat the water cleaning, at least on FM1. FM1 is the closest cavity mirror to the beam dump damaged by the high-power laser pulse.
Maybe we should also clean the AR side of FM1 and BS1, as they were right next to the damaged beam dump. It is not for the loss but for reducing the scattering.

  464   Fri Dec 2 11:42:03 2022 KojiOpticsCharacterizationOMC #1 cleaning for water soluble contaminants
[Camille, Koji] Log of the work on Nov 30, 2022
 
The following is the notes from GariLynn

Cleaning for water-soluble contaminants:
It uses deionized water instead of acetone.
Note:
  • The first contact must go on the mirror before the water can dry,  so you will need a bigger brush. We have some that are 1cm, I think they are in the back wall cabinet of B119.
  • For the bigger brush, you will need a beaker and perhaps a bigger bottle of First Contact.  There is one in the mini-fridge in the back corner of B110
  • You use an alpha swab instead of a cotton bud
  • For this effort, I encourage you to get a bottle of DI water from stores.
  • I also encourage you to rehearse the motions beforehand - timing is critical, and your mirrors are in a tight spacing

(Attachment 1)
We obtained Regent grade DI water. It was poured into a smaller cup.
FC liquid was also poured into a small beaker.
Wash the mirror with a swab. We should have used a smaller swab that GariLynn has in her lab.

As soon as the mirror was wiped with the water, the FC was applied with a large brush. Don't let the water away!
Then more layer of the FC was added as usual.


The quick painting of FC made a mess around the mirrors due to excess liquid (Attachment 2). So, we decided to remove the FC remnants (on non-optic surfaces) with cotton swabs and then applied FC as usual.

This made the mess removed, however, we found the OMC loss was increased to >10%(!) (Attachment 3). We decided to continue tomorrow (Thu) with more weapons loaded consulting with GariLynn.

 

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

Aaron took the set to Cryo lab

 

  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

 

  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.

  460   Thu Nov 17 19:50:00 2022 KojiOpticsCharacterizationConclusion on the cleaning of OMC #001

Conclusion on the cleaning of OMC #001

- After a couple of first contact cleaning trials and deep cleaning, the total loss was measured to be 0.045+/-0.004.
  This indicated a slight improvement from the loss measured at LLO before any cleaning (0.064+/-0.004).
  However, the number did not improve to the level we marked in 2013 (0.028+/-0.004).

- This loss level of 4.5% is comparable to the loss level of OMC #3, which is currently used at LHO.
  Therefore, this OMC #1 is still a useful spare for the site use.

- Some notes / to-do regarding this unit:
  1) The beam dump with melted black glass was removed. A new beam dump needs to be bonded on the base.
  2) The connector bracket still needs to be replaced with the PEEK version.
  3) The PZT of CM1 has been defunct since 2013. Combining LV and HV drivers is necessary upon use at the site. (LLO used to do it).

  459   Thu Nov 17 18:56:22 2022 KojiOpticsGeneral Transmission measurements of OMC #1 after deep cleaning

[Camille, Koji]

- Removed the first contact we left on Monday.

- Measured transmission (Set1) Very high loss! Total optical loss of 18.5%! Observation with the IR viewer indicated that CM1 has bright scattering. We suspencted a remnant of FC.

- Applied the second FC on the four cavity mirrors. This made the CM1 sport darker.

- Measured the transmission (Set1~Set3). We had consistent loss of 4.2~5.0%. We concluded that this is the limitation of this OMC even with the cleaning.

  458   Tue Nov 15 11:12:24 2022 KojiOpticsGeneralOMC #1 fogging on the AR side of BS1 cleaned

[Camille, Koji]

Photo of the BS1 AR cleaning process

Attachment 1: Before cleaning. Foggy surface is visible.

Attachment 2: After FC cleaning. The structure of the deposited material is still quite visible.

Attachment 3: Acetone scrubbing. Cotton Q-tip was used so that the stick does not melt with acetone.

Attachment 4: After acetone scrubbing. Nicely clean!

Acetone scrubbing was applied to HR/AR of BS1, FM1, FM2, BS2, and HR of CM1 and CM2. (total 10 surfaces)
Then final FC paint was applied to these 10 surfaces.

We'll come back to the setup on Thu for FC peeling and loss measurement.

  457   Tue Nov 15 10:58:53 2022 KojiOpticsGeneralOMC #1 damaged black glass removal

[Camille, Koji]

The damaged black glass was removed from the OMC breadboard leaving the glass base.
The black glass pieces were bonded very tightly on the FS base with EP30-2. The apparent amount of the bond was not so much but it was such hard that removal by hand was not possible.
We decided to give drips of Acetone on the base hoping the gradual dissolving of EP30-2. Using a knife edge, the "filets" of the bonds were removed, but the BD was still tight.

By wedging the black glass-black glass bonding with the nife edge, the left side (the directly damaged one) was taken off from the structure leaving a tiny fragment of the glass on the base.

The remaining one was even stronger. We patiently kept dripping Acetone on the base and finally, the black glass piece was knocked off and removed from the base.

Attachment 1: The base right after the black glass removal.

Attachment 2: The black glass pieces were stored in a container with Al foil + clean cloth bed. The damaged and fogged surfaces faced up.

Attachment 3: The zoom-in shot of the black glass pieces.

Attachment 4: The base was wiped with Acetone and cleaned with FC. We will bond another BD assembly on the base, presumably using the UV epoxy.

  456   Tue Nov 15 07:46:58 2022 Camille MakaremOpticsGeneralcleaning OMC #1

Monday, November 14, 2022

Camille and Koji did a "deep cleaning" of OMC#1:
1) Applied First Contact to the mirror surfaces. Removed first contact after ~10 minutes.
2) Acetone scrub of the mirror surfaces with a cotton swab.
3) Applied First Contact again. Removed after ~10 minutes. We left the FC paint on for the work on Thu.

The foggy spot on the input mirror was unchanged after the first round of First Contact. But the foggy spot came off during the acetone scrub.

  455   Mon Nov 14 09:27:13 2022 KojiOpticsCharacterizationtransmission measurements through OMC #1 (before cleaning)

The measured total optical loss of the OMC was

1st:   0.015 +/- 0.003
2nd: 0.085  +/- 0.005
3rd:  0.0585+/- 0.0008
4th:  0.047  +/- 0.002

In avegrage the estimated loss is
Loss = 0.055 +/- 0.014

This is unchanged from the measurement at LLO after the FC cleaning
Loss = 0.053 +/- 0.010

  454   Mon Nov 14 08:34:45 2022 CamilleOpticsCharacterizationtransmission measurements through OMC #1 (before cleaning)

[Camille, Koji]

Friday, Nov 11th, 2022

Setting up OMC #1 for transmission measurements:

The laser beam was aligned to the OMC cavity. The OMC cavity was locked and the transmission measurements were recorded.

  453   Fri Nov 11 19:07:48 2022 KojiSupplyGeneralSupply Order

Clean Supply Ordered

  • TexWipe TX8410 AlphaSat Vectra Alpha 10 50 sheets x 12 pk  (VWR TWTX8410)
  • Mask KIMTECH PURE® M3 Pleat-Style Face Masks 50 masks x 10 pk (VWR 15628-213)
  • Stainless Pan x3 (VWR 10193-562)
  • Ansell Accutech Latex Gloves 6.5 25*8pk (Fisher 19162026)
  • Ansell Accutech Latex Gloves 7.0 25*8pk (Fisher 19162027)
  452   Mon Nov 7 22:00:33 2022 KojiOpticsConfigurationSetting up the fiber couplers

Fiber matching: 43.2/56.7 = 76%
S/P-pol ratio 0.7/43.2 = 1.6%

 

  451   Mon Nov 7 21:16:16 2022 CamilleOpticsConfigurationSetting up the fiber couplers

[Camille, Koji]

Began setting up fiber assembly for OMC testing:
-Aligned fiber mount to maximize transmission through fiber
-Adjusted polarization at output of fiber to minimize s-polarized output.

Power measurements:
fiber input: 56.7 mW
fiber output:43.2 mW
s-polarized output: 700 uW

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

OMC #001

OMC #002

  449   Tue Sep 20 08:54:33 2022 KojiGeneralGeneralPD cage arrangement

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

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

  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

Electronics

  • 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
  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.

  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.

  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.

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

Inspection

 

  443   Wed Aug 24 03:20:59 2022 KojiGeneralGeneralOMC #002 Delamination repair Part2 (2)

Bonding

  442   Wed Aug 24 02:57:43 2022 KojiGeneralGeneralEP30-2 bonding setup

EP30-2 bonding setup

  441   Wed Aug 24 02:53:46 2022 KojiGeneralGeneralOMC #002 Delamination repair Part2 (1)

Inspection of the delaminations in the optics side

  440   Wed Aug 24 02:51:23 2022 KojiGeneralGeneralOMC #002 Delamination repair Part1 (3)

Inspection of the bonding on the suspension interface side. All look good.

  439   Mon Aug 15 22:49:03 2022 KojiGeneralGeneralOMC #002 Delamination repair Part1 (2)

EP30-2 preparation

  • Two Al foil cups + A sheet of Al foil (for test cure)
  • Set a tube on the glue gun
  • Attach an applicator tube
  • Push a couple of times, and dispense the glue for a single stroke on a waste Al cup
  • Pour the 6g of glue to the other cup.
  • Add 0.3g of silica beads powder to the cup
  • Steer. Pick a few drops to the test cure Al foil
  • Bake the test piece for 15min in 200F (95degC) ==> Very good

#1 The Invar bar on the cable bracket (DCPD side)

Added short (frosted) Al bars (Attachment 1) to the short sides of the invar bar. (Attachments 2/3). Some glue was sucked into the delamination gap by capillary action (=good) (Attachment 4)

#2 The Invar bar on the cable bracket (QPD side)

Added short (frosted) Al bars to the short sides of the invar bar. (Attachments 3/5). Maybe some glue was sucked into the delamination gap??? Not so clear. (Attachment 4)

#3 The Invar bar reinforced in 2016

Added a short (frosted) Al bars to a short side of the invar bar (Attachment 6). On both sides of the 2016 reinforcement, rectangular prisms are added (Attachment 6)
Some capillary action is visible beneath the invar bar (Attachment 7)


Leave it as it is for a day

 

  438   Mon Aug 15 22:43:35 2022 KojiGeneralGeneralOMC #002 Delamination repair Part1 (1)

[Stephen Koji]

Checked the delamination status:

  • The Invar bar on the cable bracket (DCPD side): Almost all delaminated (Attachment 1 left)
  • The invar bar on the cable bracket (QPD side): Rims still intact, center delaminated (Attachment 1 right)
  • The invar bar reinforced in 2016: One of the reinforcement bar half delaminated (Attachment 2)
  437   Mon Aug 15 22:06:18 2022 KojiGeneralGeneralOMC #002 new cable tie installed

[Stephen Koji]

New cable ties were installed on the cable pegs attached to the long sides of the cable bracket.

 

  436   Mon Aug 15 21:31:56 2022 KojiGeneralGeneralOMC #002 Cable bracket replacement (6)

The cable bracket was successfully replaced.

  • Looking from the QPD side (North side in Attachment 1), the connectors for the DCPDs and PZT are sticking out, and the ones for QPDs are sticking to the other side. So only two rectangular holes (for QPDs) are facing north.
    • Top left is DCPDT
    • Top right is DCPDR
    • Bottom center is PZT
    • Bottom left is QPD (far/long)
    • Bottom right is QPD (near/short)
       
  • First, the cable pegs for the short sides are fastened with the original screws (Vented BHCS 1/4-20).
  • Then, the cables are started to be inserted from the bottom so that the nuts can be rotated with the spanner. The spanner helped a bit but the nut only has two positions to hook the spanner and the clearance is not sufficient to insert the spanner when one of the hook positions is facing the bottom. The enlarged hole (29/64") perfectly worked . The flange of the connector can be held with a rectangular hole, so a bit bigger hole than the connector size was not an issue. Finally, all the cables were attached to the bracket.
  • The bracket has not yet been fixed on the OMC breadboard yet. This was done with the four screws from the top. Along with the assembly document E1300201, the fastening torque was limited to 2 in-lb using a digital torque wrench.
  • Attachment 2 shows the view from the "North" side. Attachment 3 shows the view from the "South" side. The cables were not yet tied on the cable pegs on the long side of the bracket.
  435   Thu Aug 11 15:24:57 2022 KojiGeneralGeneralOMC #002 Cable bracket replacement (5)

- The hole size extension is going forwared now.

- Madeline and Chub are cleaning (sonicating) a drill (29/64=0.4531")
- The parts in a bag were brought to the 40m C&B lab.

- The hole is going to be 11mil=0.28mm larger than the recommendation (0.442").
  It's not a D-hole. The connector has a rounded-rectangular flange that fits into the PEEK parts.
  So I don't think it's an issue.

- Chub has a proper spanner to fasten the nuts. We want to use it here and LLO.

 

  434   Wed Aug 10 18:42:27 2022 KojiGeneralGeneralOMC #002 Cable bracket replacement (4)

[Stephen Koji]

Now we got the C&Bed parts to continue to work on the cable bracket replacement.

1) Helicoil insertion

1/4-20 Helicoils were inserted into the 6 thread holes of D1300052. It went mostly okay. We witnessed that the Helicoil insertion tool delaminated the plating of the Helicoils upon insertion (Attachment 1). Stephen mentioned that this is not usual, but we didn't find anything further such as increased friction, more debris, etc. So we decided to go forward.

2) EP30-2 Kit

The EP30-2 kit was transferred from the 40m clean room to the OMC lab. The EP30-2 kit tracking was updated via C1900343

3) D1300052 reinstallation -> FAIL

Now resumed to the installation of D1300052 bracket. However, the hole size of the bracket is just a bit too small compared with the size of the mighty mouse connectors. It was already quite tight with the metal version. However, this PEEK version seems to have 0.1 mm further small diameter, and then the connectors do not penetrate the holes. The plan could be
1) Use a razor blade to shave the hole inner circle.
2) Use a cleaned drill bit to make the hole size 0.2mm bigger.

  433   Thu Jul 28 00:46:47 2022 KojiGeneralGeneral Subject: OMC #002 Cable bracket replacement (3)

Checking the spare parts

- Conclusion for OMC#2: need PEEK cable ties
- for more OMCs: need more BHCS / PEEK cable ties / Helicoils

  • Helicoils: 1/4-20 0.375 helicoils / Qty 4 / Class A (Attachment 1)
    • looks like there are many more as the transport fixture bags (Attachment 2). Stephen noted that they are meant to be CLASS B
       
  • Cable pegs: D1300057 / Qty 24 + 3 recycled from OMC#2 / Class A (Attachment 3)
    • Requirement: 3+3+4 = 10 for the 4th OMC / 3x4 =12 for the cable bracket replacement -> we have enough
       
  • PEEK Cable Ties: Stephen reported they were deformed by baking heat... did not check how they are in the bags.
     
  • Button Head Cap Screws 1/4-20 length ? none found in the bags.
    • Qty 4 spare (forgot to take a picture) + 3 recycled. So we have sufficient for OMC#2
  432   Thu Jul 28 00:28:15 2022 KojiGeneralGeneral OMC #002 Cable bracket replacement (2)

Connector unmounting

- (Attachment 1) The connector nut rings were removed using an angled needle nose plier. The connector shell has a tight dimension relative to the hole on the bracket. But of course, they could be extracted.

- The 4 screws mounting the bracket to the invar blocks were successfully removed. No extra damage to the bonding.

- (Attachment 2) The plan was to remove the cable pegs by unfastening the button head 1/4-20 screws from the bracket and then just replace the bracket with the new one. However, these screws were really tight. The two were successfully removed without cutting the PEEK cable ties. Two cable ties were necessary to be cut to detach the bracket+pegs from the fragile OMC. Then one screw was removed. However, the final one could not be unfastened. This is not a problem as we are not going to recycle the metal cable bracket... as long as we have spare parts for the new bracket.

- (Attachment 3) Right now, the new bracket is waiting for the helicoils to be inserted. So the OMC lid was closed with the cables piled up. Just be careful when the lid is open.

  431   Wed Jul 27 23:52:18 2022 KojiGeneralGeneralOMC #002 Cable bracket replacement (1)

Parts check

- D1300052-V3 SN001 is going to be used (Attachment 1)

- This is the PEEK version of the cable bracket (Attachment 2). The side thread holes have no Helicoils inserted. This needs to be done!
 

Connector arrangement check / cable routing check

Attachment 3: Connector Arrangement from the Northside

Attachment 4: Connector Arrangement from the South side

Attachment 5: Cable routing (Northside down)

At this point, the delamination of the V shape beam dumps was visible. This is the subject of bonding reinforcement.

  430   Wed Jul 27 10:34:30 2022 KojiGeneralGeneralOMC #002 Protective FirstContact Paint

The optical surfaces were coated with FirstContact to keep them clean / somewhat protected during the transportation.
The PD aperture was sealed with FirstContact "caps" (made by Kate in 2016?).

  429   Wed Jul 27 10:34:09 2022 KojiGeneralGeneralHigh QE PD: QE measurements 2

- DLPCA-200 trans-impedance amplifier was calibrated.
  Keithley source meter 2450 was connected to the amp. Provide current and read the output voltage with the precision digital voltage meter (Agilent/Keysight).
  Gain: 999.7V/A@7mA, 999.6V/A@8mA

- From the power meter spec, Thorlabs S401C seemed the best (+/-3%). So the QEs of the 9 PDs were checked with this power meter again.

- All PDs exhibited the QE of 0.95~0.96. It's all relative as the power meter has a systematic error.
- Tried to clean B1-22 and B1-23 PDs. They didn't show significant improvement after the cleaning. To avoid the unnecessary risk of damaging the PDs, further cleaning was not performed. (Some photos were attached)

- What we can do is use this result as the relative measurements.
- For OMC#2, B1-22 is the DCPD(T) and B1-23 is the DCPD(R). C1-03 and C1-12 are the spares, according to this latest result.
- At LLO, we track down the source of the throughput reduction (-10%). The QEs of the PDs are going to be tested in the same setup at once to compare their PDs and our PDs.

PD Type SN Case DCV1 Pin [mW] dPin [mW] Power Meter DCV2 Avg(DCV) Std(DCV) DCVOFS (mV) Responsivity [A/W] dR QE dQE Date Note
IGHQEX3000 B1-22 B1 7.734 9.43 0.02 TL 401C 7.745 7.7395 0.006 -0.0260 0.821 0.002 0.957 0.002 July 26, 2022 clean1 / installed (T)
IGHQEX3000 B1-23 B2 7.679 9.26 0.02 TL 401C 7.709 7.6940 0.015 -0.0220 0.831 0.002 0.969 0.003 July 26, 2022 clean1 / installed (R)
IGHQEX3000 C1-03 B3 7.775 9.40 0.02 TL 401C 7.770 7.7725 0.003 -0.0450 0.827 0.002 0.964 0.002 July 26, 2022 clean3
                                 
IGHQEX3000 C1-08 C2 7.717 9.45 0.02 TL 401C 7.750 7.7335 0.017 -0.0430 0.819 0.002 0.954 0.003 July 26, 2022 initial
IGHQEX3000 C1-09 C3 7.737 9.50 0.05 TL 401C 7.776 7.7565 0.019 -0.0580 0.817 0.005 0.952 0.006 July 26, 2022 initial
IGHQEX3000 C1-10 C4 7.757 9.50 0.03 TL 401C 7.774 7.7655 0.009 -0.0650 0.818 0.003 0.953 0.003 July 26, 2022 initial
                                 
IGHQEX3000 C1-11 D1 7.826 9.66 0.01 TL 401C 7.828 7.8270 0.001 -0.0570 0.810 0.001 0.945 0.001 July 26, 2022 initial
IGHQEX3000 C1-12 D2 7.841 9.51 0.02 TL 401C 7.841 7.8410 0.000 -0.0410 0.825 0.002 0.961 0.002 July 26, 2022 initial
IGHQEX3000 C1-14 D3 7.769 9.55 0.01 TL 401C 7.789 7.7790 0.010 -0.0520 0.815 0.001 0.950 0.002 July 26, 2022 initial
  428   Wed Jul 27 10:09:51 2022 KojiGeneralGeneral4+4 wire clamp in hand

Regarding: D1200971

- 4 CLASS A wire clamp obtained from the OMC spare
- 4 more DIRTY wire clamp obtained from WB experiments (they no longer use these)

Once the later ones are C&Bed, we have enough.

 

  427   Tue Jul 26 00:12:58 2022 KojiGeneralGeneralHigh QE PD: QE measurements

- Installed the High QE PDs to OMC #002

  • B1-22@Cage B1 was installed to the transmission DCPD
  • B1-23@Cage B1 was installed to the reflection DCPD

Upon the installation, the legs of the PDs were cut by 3mm. Also, the tab of the PD could not be embedded in the DCPD housing. Therefore, the tabs were cut.

The alignment looked just fine. The weak reflections are directed to the black glass beam dumps.

- After the installation, the QEs were measured.

  • With Thorlabs S130C power meter, the QE was estimated to be ~95%. (Accuracy +/-7%)
  • With Thorlabs S401C power meter, the QE was estimated to be ~100%. (Accuracy +/-3%)

It is so confusing. So I decided to make the QE test setup.


Ophir RM9 with chopper (+/-5%): 8.97mW
Thorlabs S140C integrating sphere (+/-7%): 9.11mW
Thorlabs S130C PD power meter (+/-7%): 9.15mW
Thorlabs S401C thermal power meter (+/-3%): 8.90mW
So there looks ~3% discrepancy between S130C and S401C

Then tried to measure the QE of C1-03@Cage B3 with Ophir RM9
- Initial state: QE=0.95
- First FirstContact application: QE went up to 0.973
- Second FirstContact application: QE = 0.974, basically no change


To Do:
- Calibrate the trans-impedance amp with Keithley
- Apply FC to B1-22 and B1-23 to see if there is an improvement
- The power should be measured with S401C because the accuracy seems better (+/-3%).
- Take photos of the PD FC process

General To Do:

- Backscatter test 2nd trial

- Start applying the first contact to the optical surfaces
- Beam dump cleaning
- Apply FC cap to the PDs
- Delamination repair (light side)
- Delamination repair (dark side)
- Cable bracket replace (dark side)

 

  426   Tue Jul 26 00:01:59 2022 KojiGeneralGeneralOMC #002 delamination check 2

More epoxy delamination check:

DCPD R (Attachment 1): Found half delaminated

DCPD T (Attachment 2): Found half delaminated

QPD1/QPD2 (Attachment 3): Looks fine

------

In total we need to fix bonding of three invar bases (including the one for the cable bracket)

  425   Mon Jul 25 18:25:04 2022 KojiGeneralGeneralA/C Filter was replaced
New filter PN
Grainger
TK70457312T Mini-Pleat Air Filter, Style - Air Filters Box, Performance Rating MERV 14, Nominal Filter Size 12x24x2
 
Previous filter PN
Global Industrial Equipment
Extended Surface Pleated Cartridge Filter Serva-Cell Mp4 Slmp295 12X24X2 Gl WBB431699
-> No longer available
  424   Fri Jul 22 17:47:38 2022 KojiGeneralGeneralC&B request for the reinforcement blocks

OMC Reinforcement blocks

1. P/N D1600316; Version v4; Type 01; Qty 30; Source Chemistry Machine Shop
2. P/N D1600316; Version v4; Type 02; Qty 15; Source Chemistry Machine Shop
3. P/N D1600316; Version v4; Type 01; Qty 40; Source Resource MFG PO S422806
4. P/N D1600316; Version v4; Type 02; Qty 40; Source Resource MFG PO S422806

Stephen asked Srinath for the ICS entry.
Stephen made the C&B request https://cleanandbake.ligo.caltech.edu/clean_and_bake/request/1708/

Madeline was asked to take care of the C&B.

Also, the Torr Seal box was returned to Madeline.

  423   Fri Jul 22 17:41:01 2022 KojiGeneralGeneralSRS LCR meter SRS720 returned to Downs

SRS LCR meter SRS720 was returned to Downs as before.

 

  422   Fri Jul 22 00:31:17 2022 KojiGeneralGeneralOMC #002 backscatter measurement

Measure the power ratio between the forward-propagating and reverse-propagating beams.

  1. Place a small deflecting mirror at the transmission.
  2. Place a flat mirror at the deflected transmission. When the alignment of this mirror is adjusted to retroreflect this beam, the DC of the cavity reflection PD increases, and also the CCD shows spurious fringes.
  3. This condition allows us to locate the power meter at the reverse-propagating spot of the transmission (Attachment 1)
  4. Place a black glass beam dump for the main (bright) transmission (Attachment 2)
  5. Now the power meter is receiving the counter-propagating beam. Turn off the room light and place an anodized Al baffle as shown in Attachment 2. Move the baffle to block only the counter-propagating. Move the baffle out. => Record the power meter reading with/without the baffle in the counter-propagating path. The difference is the power of the reverse-propagating beam.
  6. Now measure the power of the reflected main transmission. This tells us the power ratio between the foward- and back-propagating beams.
  7. Remove the small deflecting mirror and measure the power of the main transmission.
  8. Now the back-propagating power can be estimated from 6 and 7. The same amount is going back to the IFO path.
  9. The reflectivity can be calculated from the 7 and the transmission

- To increase the incident laser power, NPRO Current ADJ was set to be 0 (increased from -50)

- 1st:  Without the baffle 0.373 +/- 0.001 uW / With the baffle 0.318 +/- 0.001 uW
- 2nd: Without the baffle 0.370 +/- 0.001 uW / With the baffle 0.318 +/- 0.001 uW
- 3rd: Without the baffle 0.370 +/- 0.001 uW / With the baffle 0.317 +/- 0.001 uW

==> 53.3 +/- 0.6 nW

- The main transmission was 84.0mW
==> Backpropagation ratio was 0.634+/-0.007 ppm

- Direct measurement of the OMC was  after BS 96.6mW
==> Backpropagation power from the cavity: 61.3 +/- 0.7 nW

- Cavity transmission for the matched beam is Tcav RinputBS = 0.963
==> Incident resonant TEM00 power 100.3mW

- Reflection 61.3+/-0.7 nW x RinputBS = 60.8+/-0.7 nW
-> The effective reflectivity for the mode-matched resonant TEM00 beam incident on the OMC (1st steering mirror) is 0.606+/-0.007 ppm

  421   Thu Jul 21 17:47:00 2022 KojiGeneralGeneralThe profile of the beam incident on the fiber input coupler

The profile of the beam incident on the fiber input

The fiber input was deflected by a 45deg mirror. The beam profile was measured with WincamD. The beam was too strong (~60mW) even at the smallest pump power (ADJ -50) of the NPRO. So the two ND20 filters were added to the lens right before the 45 deg mirror and the camera.

The measured profile had some deviation from the nice TEM00 particularly around the waist. This could be a problem of the too small beam on the ND filter and the CCD.
This is not an issue as we just want to know the approximate shape of the beam.

For the fiber coupling, if we have the beam waist radius of ~200um it is sufficient for decent coupling.

  420   Thu Jul 21 14:55:48 2022 KojiGeneralGeneralOptics bonding for the backscatter measurement

The backscatter beam is supposed to appear in the backpropagation path. The transmission of the OMC has a couple of optics, it's not easy to access that beam.
To try to deflect the beam either horizontally or vertically, small optical pieces were made. (Attachment)

These are the combination of the optics

- Thorlabs PF05-03 Fused Silica Mirror Blank (dia12.7mm x t 6.0mm) + Thorlabs 1/2"sq BB Dielectric Mirror BBSQ05-E03

- Thorlabs PF05-03 Fused Silica Mirror Blank (dia12.7mm x t 6.0mm) + Thorlabs ME05-G01 Protected Al Mirror (dia12.7mm x t 3.2mm) + Thorlabs MRA10-K13 Right-Angle Prism Nd:YAG 10mm

Torr seal was used as the bonding epoxy. It uses a 1:2 volume mixture (not easy because of the viscosity) and is relatively fast to cure (in a couple of hours).
The test piece showed some softness after 3~4 hours so I left the parts cured overnight at room temp (i.e. 18degC)

  419   Thu Jul 21 14:35:35 2022 KojiGeneralGeneralBond reinforcement blocks for the invar brackets

Bond reinforcement blocks for the invar brackets:

  • Attachment 1: CLASS A glass prisms (the surplus of the 2016 repair)
  • Attachment 2: Dirty reiforcement bars made of Aluminum
  • There are also many dirty prisms in the kit obtained from Stephen
  418   Thu Jul 21 13:21:27 2022 KojiGeneralConfigurationWindows laptop for WincamD Beam'R2 recovery

The Windows laptop for WincamD/Beam'R2 (DELL Vostro3300) was not functional.
- Windows 7 got stuck in the starting up process (Google "startup repair loop")
- The battery can't charge and the adapter connection is flaky

I decided to newly install Win10.
I made a new bootable Win10 DVD from the ISO downloaded from IMSS. The ISO file was converted to CDR using Disk Utility on Mac.
This deleted the past disk partitions. The installation process has no trouble and Win10 ran successfully. The machine is slow but still acceptable for our purpose.
Dataray Version 7.1H25Bk was downloaded from the vendor website https://dataray.com/blogs/software/downloads and installed successfully.
The devices ran as expected by connecting the heads and selecting the proper device in the software.

Then, the Win10 fell into "Hibernation Loop" and "Shutdown loop" (after disabling hibernation in the safe mode).
This is probably the combination of extremely slow windows update (feature update i.e. beta OS update) and the occasional shutdown due to the flakiness of the AC connection

Win10 was reinstalled and automatic Win update was disabled via windows policy manager or something like that. Still, it tries to download and update some of the updates (what's happening there!?

Here are my strong recommendations on how to use this laptop

  • Do not use any network connection. It will enable Windows Update kicks in and destroy the machine.
  • Use a USB stick for data transportation if necessary
  • Buy a replacement battery (maybe a 3rd-party cheap one
  • The Win10 DVD should always be inserted into the laptop's drive so that we can reinstall the windows anytime.
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