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New entries since:Wed Dec 31 16:00:00 1969
ID Dateup Author Type Category Subject
  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%

 

  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)
  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.

Attachment 1: PXL_20221111_200942943.jpg
PXL_20221111_200942943.jpg
Attachment 2: PXL_20221111_200957951.jpg
PXL_20221111_200957951.jpg
  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

Attachment 1: OMC_Powerbudget.xlsx
  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.

  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.

Attachment 1: PXL_20221114_222641455.jpg
PXL_20221114_222641455.jpg
Attachment 2: PXL_20221114_222544330.jpg
PXL_20221114_222544330.jpg
Attachment 3: PXL_20221114_222555849.jpg
PXL_20221114_222555849.jpg
Attachment 4: PXL_20221114_233748631.jpg
PXL_20221114_233748631.jpg
  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.

Attachment 1: PXL_20221114_225338114.jpg
PXL_20221114_225338114.jpg
Attachment 2: PXL_20221114_232824245.jpg
PXL_20221114_232824245.jpg
Attachment 3: PXL_20221114_233714774.jpg
PXL_20221114_233714774.jpg
Attachment 4: PXL_20221114_233748631.jpg
PXL_20221114_233748631.jpg
  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.

Attachment 1: PXL_20221117_232145418.jpg
PXL_20221117_232145418.jpg
Attachment 2: Screen_Shot_2022-11-17_at_19.02.31.png
Screen_Shot_2022-11-17_at_19.02.31.png
  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).

Attachment 1: OMC_loss.pdf
OMC_loss.pdf
  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.

Attachment 1: PXL_20221118_213955948.jpg
PXL_20221118_213955948.jpg
  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

 

Attachment 1: PXL_20221122_030736513.jpg
PXL_20221122_030736513.jpg
Attachment 2: OMC_loss.pdf
OMC_loss.pdf
  463   Tue Nov 29 15:54:47 2022 KojiGeneralConfigurationWindows laptop for WincamD Beam'R2 recovery

Aaron took the set to Cryo lab

 

  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.

 

Attachment 1: PXL_20221130_234101575.jpg
PXL_20221130_234101575.jpg
Attachment 2: PXL_20221130_234013958.jpg
PXL_20221130_234013958.jpg
Attachment 3: PXL_20221201_021727724.jpg
PXL_20221201_021727724.jpg
Attachment 4: Screen_Shot_2022-12-02_at_12.43.02.png
Screen_Shot_2022-12-02_at_12.43.02.png
  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.

Attachment 1: PXL_20221202_034932211.jpg
PXL_20221202_034932211.jpg
Attachment 2: OMC_loss.pdf
OMC_loss.pdf
  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.

Attachment 1: PXL_20221203_063327268.jpg
PXL_20221203_063327268.jpg
Attachment 2: OMC_loss.pdf
OMC_loss.pdf
  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
Attachment 1: PXL_20221205_233712211.jpg
PXL_20221205_233712211.jpg
  468   Fri Dec 9 13:13:13 2022 KojiOpticsCharacterizationFSR/TMS/Spot Positions/Transmission

[Camille Koji]

We quickly measured the basic parameters of the OMC as is.

=== FSR ===
Used the technique to find a dip in the transmission transfer function (TF) with offset locking + phase modulation. The FSR was 264.79003MHz = The cavity length of 1.13219 [m] (requirement 1.132+/-0.005 [m])

=== TMS ===

Used the technique to find the peaks in the trans TF with phase modulation + input misalignment + trans PD clipping.
TMS_V: 58.0727 / TMS_H: 58.3070 => TMS/FSR V:0.219316 H:0.220201

This makes the 9th-order modes nicely avoided (Attachment 1). A slightly longer FSR may makes the numbers close to the nominal.

=== Spot positions ===

The image/video capture board turned out not functional with the new Apple silicon mac. We decided to use a small CCD monitor and took a photo of the display.

All the spots are within the acceptable range. The scattering on CM2 was particularly bright on the CCD image and also in the image with the IR viewr.

The spot on FM1/2 are right at the expected location. The spot on CM1 is 0.5mm low and 0.7mm inside (left). The spot on CM2 is ~0.25mm too high and 0.3mm outside.
(Attachment 2, a small grid is 1 mm/div)

== Transmission ==

We made a quick simplified measurement (Attachment 3).

Assuming the reflectivity of the matched beam to be ~0, the mode matching is M=1-(59.2e-3-(-6.5e-3))/(3.074-(-6.5e-3))=0.979
==> The power of the coupled mode is M x 21.28mW = 20.83 mW
The measued transmission was 19.88 mW

==> The OMC transmission (total) was 0.954 (4.5% loss)

This number is not too bad. But the spot on CM2 has too bright scattering. Next week, we want to check if swapping CM2 may improve the situation or not.

Attachment 1: HOM_plot_PZT.pdf
HOM_plot_PZT.pdf
Attachment 2: OMC4_spot.png
OMC4_spot.png
Attachment 3: PXL_20221208_233706115.jpg
PXL_20221208_233706115.jpg
  469   Mon Dec 12 19:04:40 2022 KojiOpticsCharacterizationFSR/TMS/Spot Positions/Transmission 2nd trial

[Camille Koji]

We replaced CM2 with a PZT mirror subassembly serialized by PZT "13" (Attachment 1).
This made the transmission increase to 96.x%. Therefore the quick measurement of FSR and TSM were done. Also more careful measurement of the transmission was done.

Next time


== Alignment ==

  • CM2 was replaced from PZT "12" to PZT "13".
  • The resulting position of the cavity spot were all over 1mm too "+" (convention T1500060 Appendix C).
  • So we decided to rotate CM2 by 1mrad in CW. This was done with (-) micrometer of CM2 "pushed" by 20um (2 rotational div).
  • The resulting spot positions were checked with CCD. (Attachment 2). The spot positions seemed to be within +/-1mm from the center as far as we can see from the images. (good)
  • CM2 spot looks much darker. CM1 spot is almost invisible with a CCD and also an IR viewer. FM1/2 spots were nominal bright level. (Looks OK)

== Quick measurement of the transmission ==

Transmission: 20.30 mW
Reflection Voltage (locked): 65.0 mV
Reflection Voltage (unlocked): 3.094 V
Reflection Voltage (dark): -6.5 mV
Incident Power: 21.64 mW

---> Mode matching 1-0.023 / Pcoupled = 21.14 / OMC Transmission 0.96

96% transmission is not the best but OK level. We decided to proceed with this mirror combination.

== Quick measurement of FSR/TMS ==

FSR: 264.7837MHz
TMS_V = 58.2105MHz
TMS_H = 58.1080MHz

The HOM structure (with PZT Vs = 0) is shown in Attachment 3. 9th order modes look just fine. The excplicit coincidence is 19th order 45MHz lower sideband. (Looks good)

== Transmission measurement ==

The raw measurements are shown in Attachment 4. The processed result is shown in Attachment 5.
We found that data set 2 has exceptionally low transmission. So we decided to run the 4th measurement excluding the set 2.

Over all OMC loss
Set1: 0.029 +/- 0.014
Set3: 0.041 +/- 0.0014
Set4: 0.038 +/- 0.001

--> 0.036 +/- 0.004
(0.964 Transmission)

 

Attachment 1: PXL_20221212_235351320.jpg
PXL_20221212_235351320.jpg
Attachment 2: OMC4_spot.png
OMC4_spot.png
Attachment 3: HOM_plot_PZT.pdf
HOM_plot_PZT.pdf
Attachment 4: PXL_20221213_000406843.jpg
PXL_20221213_000406843.jpg
Attachment 5: Screen_Shot_2022-12-12_at_19.36.10.png
Screen_Shot_2022-12-12_at_19.36.10.png
  470   Mon Dec 19 18:51:50 2022 KojiOpticsCharacterizationTMS measurement with the PZT voltages altered

[Camille, Koji] Log of the work on Dec 15, 2023

The vertical and horizontal TMSs for OMC #4 were measured with the PZT voltages scanned from 0V to 200V.

We concluded that this alignment nicely avoids the higher-order mode structure up to ~19th order. We are ready for the cavity mirror bonding.


The RF transfer functions to the trans RF PD from the modulation on the BB EOM were taken with the presence of the vertical misalignment of the incident beam and the vertical clipping of the beam on the RFPD.

The typical measurement results and the fitting results are shown in Attachments 1/2.

The TFs were taken with the voltage 0, 50, 100, 150, and 200V applied to PZT1 while PZT2 were left open. The measurement was repeated with the role of PZT1 and PZT2 swapped.


The ratio between the TMS and FSR was evaluated for each PZT voltage setting. (Attachment 3)

When the PZTs are open, the first coincident resonance is the 19th-order mode of the 45MHz lower sideband. (Attachment 4)

When the PZT2 voltage is scanned with PZT1 kept at ~0V, no low-order sidebands come into the resonance (Attachment 5) until the PZT1 voltage is above 100V.

We found that the high voltage on PZT1 misaligns the cavity in yaw and the spot (presumably) moves to an undesirable area regarding the cavity loss.
This does not happen to PZT2. Therefore the recommendation here is that the PZT2 is used as the high voltage PTZ, while PZT1 is for the low voltage actuation.

 

Attachment 1: Cav_scan_response_PZT1_0_Pitch.pdf
Cav_scan_response_PZT1_0_Pitch.pdf
Attachment 2: Cav_scan_response_PZT1_0_Yaw.pdf
Cav_scan_response_PZT1_0_Yaw.pdf
Attachment 3: OMC_20221215.pdf
OMC_20221215.pdf
Attachment 4: HOM_plot_PZT0_0.pdf
HOM_plot_PZT0_0.pdf
Attachment 5: HOM_PZTV_PZT1_0V.pdf
HOM_PZTV_PZT1_0V.pdf
  471   Thu Jan 19 23:45:44 2023 KojiOpticsGeneralOMC #4: cavity mirror bonding

[Koji, Camille]

We worked on the bonding of the flat mirrors for the OMC cavity with UV epoxy.

- Prepared the UV illumination setup. Cleaned up the table a bit to spare some space for the illuminator.
- Checked the output power of the illuminator. The foot pedal worked fine. The timer was set to be 10s. The UV output from the fiber was nominally 6W. This is after some warming up for ~1min. (Checked the output power continuously with the UV power meter.)

- Checked the cavity alignment / FSR / TMS - it looked good at this moment

- We confirmed that the UV epoxy has an expiration of July 3, 2023. The bond capsule was brought from Downs right before the work started, and thawed at the lab.

FM1 bonding

- The bottom of FM1 and the breadboard were cleaned. Cleaning with lens cleaning paper + IPA remained a few specks of dust on the surface. We decided to use Vectra swabs to wipe the breadboard surface. This worked pretty well.
- Applied a tap of UV epoxy to FM1 and placed it on the template. The optic was constrained by a retainer clip.
- We found that the spot positions were significantly moved. Probably FM1 was not well touching the template before. We tried to recover the previous optical axis by aligning CM1 and CM2.
- Here is the tip: align the beam on CM1 at the desired spot. Move CM1 to bring the spot on CM2 to the desired spot. CM2 is aligned to have TEM00 as much as possible.

- We recovered reasonable spots on the mirrors. Measured the FSR and TMS (vertical and horizontal) to be 264.73MHz, 58.18MHz, and 58.37MHz, respectively. This makes the 9th-order modes well separated from TEM00. Very good.

- Gave UV illumination 10s x 2. Confirmed that the mirror is rigidly bonded.

 

FM2 bonding

- Continued to bond the other flat mirror. The same process was repeated.
- The bottom of FM2 and the breadboard were cleaned.
- Applied a tap of UV epoxy to FM2 and placed it on the template. The optic was constrained by a retainer clip.
- Measured the FSR and TMS (vertical and horizontal) to be 264.7925MHz, 58.15MHz, and 58.3725MHz, respectively. This makes the 9th-order modes well separated from TEM00. Very good.

- Gave UV illumination 10s x 2. Confirmed that the mirror is rigidly bonded.

SM1/BS2/BS3 bonding

- Continued to bond some less important mirrors.
- SM1 was placed on the template with the same step as above. BS2 (for QPD) and a dummy QPD housing were also placed just to check if the optical axis has any inconsistency. The good beam alignment on the QPD housing was confirmed.
- Applied a bond to SM1 and blasted the UV (20s)
- Applied a bond to BS2. Checked the alignment on QPD1 again. It looked good. UV illumination was applied.

- Placed BS3 to the cavity transmission. A dummy DCPD housing was placed at the reflection side of BS3. There was no inconsistency with the beam alignment.
- The UV illumination was applied (20s).


Optic Inventory

Breadboard: #6
BS1: E6
FM1: A1
FM2: A3
CM1: PZT ASSY #8 (M7+PZT11+C11)
CM2: PZT ASSY #11 (M14+PZT13+C13)
SM1: E9
BS2: B8
SM2:
SM3:
BS3: B6

  472   Mon Jan 23 19:51:20 2023 KojiOpticsGeneralOMC #4: cavity mirror bonding

[Camille, Koji]

We continued to bond two CM mirrors and the other two steering mirrors for QPD2.

Before the bonding work, the FSR and TMSs were checked again.

FSR: 264.7925 MHz
TMS_V: 58.15125 MHz
TMS_H: 58.33375 MHz

Checked the transmission: The OMC loss was 4.3 +/- 0.2 %.

This does not make the HOMs coincidently resonant until the 18th-order (+9MHz). Looks good.


CM1/CM2/SM2/SM3 bonding

- Applied the bond to CM1 and the UV illuminated.
- Applied the bond to CM2 and the UV illuminated.
==> The cavity bonding is completed.

Removed the micrometer for CM2 to allow us to bond SM2/SM3
- Checked the spot at QPD2: The spot was a couple of mm too left. This was too much off compared to the QPD adjustment range. ==> Decided to shim the SM3 position with a piece of Al foil.
- Otherwise everything looked good. SM2/SM3 were bonded.


Invar block bonding

Prepared EP30-2
- There are three tubes of EP30-2 that expires on 2/22, 2023.
- A tube was almost empty. Used this tube to fill/purge the applicator. The 2nd tube was then attached to squeeze out 8g of glue mixture. 
- 0.4g of fused silica beads were added to the glue mixture.
- Mixed the bond and a test piece was baked by the oven. (200F=95C, 5min preheat, bakeing 15min).
- The glue test piece was "dry" and crisp. Looked good.
- Applied the glue on the invar blocks. Confirmed that the bonding surfaces were made completely "wet".
- 4-40 screws were inserted to the blocks so that the blocks were pushed toward the template. See Attachments 3 and 4.

 

Optic Inventory

Breadboard: #6
BS1: E6
FM1: A1
FM2: A3
CM1: PZT ASSY #8 (M7+PZT11+C11)
CM2: PZT ASSY #11 (M14+PZT13+C13)
SM1: E9
BS2: B8
SM2: E11
SM3: E14
BS3: B6

Attachment 1: HOM_plot_PZT0_0.pdf
HOM_plot_PZT0_0.pdf
Attachment 2: PXL_20230124_032358482.MP.jpg
PXL_20230124_032358482.MP.jpg
Attachment 3: PXL_20230124_032452805.MP.jpg
PXL_20230124_032452805.MP.jpg
Attachment 4: PXL_20230124_032425638.jpg
PXL_20230124_032425638.jpg
  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.

Attachment 1: PXL_20230127_055920944.jpg
PXL_20230127_055920944.jpg
  474   Thu Jan 26 22:57:19 2023 KojiOpticsGeneralOMC #4: One Invar block bonded with tilt

[Camille, Koji]

The bottom side template was separated into two pieces and successfully removed from the breadboard. The template was assembled together again and bagged to store it in a cabinet.

We found that the invar block for DCPD(R) was bonded with some air gap (Attachment2 1/2).

 

The Allen key used as a weight was too small, which caused it to get under one of the screws used as hooks and lift the block.

 

We've investigated the impact of this tilt.

- Bonding strength: The bonding area is ~60% of the nominal. So this is weak, but we can reinforce the bonding with an aluminum bar.
- Misalignment of the DCPD housing: The tilt will laterally move the position of the DCPD. However, the displacement is small and it can be absorbed by the adjustment range of the DCPD housing.
- Removal: From the experience with the removal of the beam dump glass, this requires a long time of acetone soaking.

Conclusion:

- We don't need to remove the invar block.
- Action Item: Reinforcement of the bonding

Attachment 1: PXL_20230126_221425695.jpg
PXL_20230126_221425695.jpg
Attachment 2: PXL_20230126_221522416.jpg
PXL_20230126_221522416.jpg
  475   Thu Jan 26 23:07:14 2023 KojiOpticsGeneralOMC #4: Input beam dump bonding

[Camille, Koji]

During the second UV epoxy session, we did not bond the input beam dump. This is because this beam dump was not the one planned from the beginning and if it was bonded in place, it would have created difficulties when removing the template.

First, we aligned a couple of Allen wrenches to define the location of the beam dump. We've checked that the main transmission is not blocked at all while the stray beam from the OMC reflection is properly dumped.

After the confirmation, the UV epoxy + UV alight were applied.

The resulting position of the beam dump is shown in the attachment.

Attachment 1: PXL_20230126_221556977.jpg
PXL_20230126_221556977.jpg
  476   Thu Jan 26 23:16:35 2023 KojiOpticsConfigurationOMC #4: Top side bonding.

[Camille, Koji]

1. Flipping the OMC

It turned out that the transport fixture for this OMC could not be closed. The locks are too short, and the knobs could not be turned. We temporarily fastened the long 1/4-20 screws to secure the box and flipped it to make the top side face up.

2. Setting up the top-side template

The top side template was attached to the breadboard. We took care that the lock nuts on the positioning screws were not touched. The margins between the template and the glass edges were checked with a caliper. The long sides seemed very much parallel and symmetric, while the short sides were not symmetric. The lock nut on the short side was loosened, and the template was shifted to be symmetric w.r.t. the breadboard.

3. UV epoxy work

The cylindrical glass pieces were wiped, and the bonding surfaces were cleaned so that the visible fringes were <5 fringes. We confirmed the hooking side is properly facing up. The UV epoxy and UV curing were applied without any trouble. (Attachment 1)

4. EP30-2 bonding of the invar mounting blocks

Six invar blocks were bonded. This time the Allen key weights were properly arranged, so they didn't raise the blocks. The bond properly wetted the mating surfaces.

---

The final step of the bonding is to remove the template.
And replace the locks of the transport fixture.

 

Attachment 1: PXL_20230126_235309334.jpg
PXL_20230126_235309334.jpg
Attachment 2: PXL_20230127_053008237.jpg
PXL_20230127_053008237.jpg
Attachment 3: PXL_20230127_053020709_2.jpg
PXL_20230127_053020709_2.jpg
Attachment 4: PXL_20230127_053042809.MP_2.jpg
PXL_20230127_053042809.MP_2.jpg
Attachment 5: PXL_20230127_053058275_2.jpg
PXL_20230127_053058275_2.jpg
  477   Thu Jan 26 23:46:13 2023 KojiOpticsGeneralOMC #1 input beam dump bonding

A beam dump was stacked on the base of the previous beam dump. The angle was determined so that the main transmission goes through while the stray OMC reflection is blocked without clipping at the edge.

The resulting alignment of the beam dump is shown in Attachment 1.

The beam dump tended to slip on the base. To prevent that a couple of weights were placed around the bonding area. (Attachment 2)

 

Attachment 1: PXL_20230127_052955482.jpg
PXL_20230127_052955482.jpg
Attachment 2: PXL_20230127_052949869.jpg
PXL_20230127_052949869.jpg
  478   Sat Jan 28 00:38:56 2023 KojiMechanicsGeneralOMC #1 cable bracket replacement / OMC #1 repair completed

The AL metal bracket was replaced with a PEEK version.

Attachments 1/2: Before the replacement. The photos show how the cables are arranged.

Attachment 3: How the replacement work is going. The 1/4-20 screws were super tight. Once the connectors were removed, an Allen key was inserted to a hole so that the 1/4-20 on the short sides were removed by closing Allen key arms. For the screws on the longer sides, the same technique can be applied by using three Allen keys. This time none of the screws/cable pegs were wasted. The clothes were used to protect the breadboard from any impact of the action.

Attachments 4/5: Final state.

OMC #1 repair has been 100% done

---------

We still have 4 correct cable pegs and many 1/4-20 BHSCs for OMC #4.

Attachment 1: PXL_20230128_011405446.jpg
PXL_20230128_011405446.jpg
Attachment 2: PXL_20230128_011401778.jpg
PXL_20230128_011401778.jpg
Attachment 3: PXL_20230128_013509885.jpg
PXL_20230128_013509885.jpg
Attachment 4: PXL_20230128_014001006.jpg
PXL_20230128_014001006.jpg
Attachment 5: PXL_20230128_014035044.jpg
PXL_20230128_014035044.jpg
  479   Sat Jan 28 00:46:21 2023 KojiMechanicsGeneralOMC #4: Replaced the locks of the transport fixture

Yesterday, we noticed that we could not close the transport fixture for OMC #4. We could not fully rotate the knobs of the locks. Today, I took the hooks from the functioning locks of the spare transport fixture.

It turned out that the default dimension of the lock seemed too tight. The functioning one has the through holes elongated by a file or something. This modification will be necessary for future transport fixtures.

Attachment 1: PXL_20230128_022952669.jpg
PXL_20230128_022952669.jpg
  480   Wed Feb 1 01:33:03 2023 KojiMechanicsGeneral5th OMC Transport Fixture

The transport fixture was brought to the 40m clean room to use as an assembly reference.

Attachment 1: PXL_20230201_005912224.jpg
PXL_20230201_005912224.jpg
  481   Wed Feb 1 01:39:41 2023 KojiMechanicsGeneralDCPD housing / QPD housing

Inserted 4-40 and 2-56 helicoils into the DCPD/QPD housings for the 4th OMC. The retainer caps were also fastened to the housings.

Attachment 1: PXL_20230201_021505299.jpg
PXL_20230201_021505299.jpg
Attachment 2: PXL_20230201_021455728.jpg
PXL_20230201_021455728.jpg
  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

  483   Thu Feb 2 03:09:41 2023 KojiOpticsGeneralOMC #4: One Invar block bonded with tilt

[Camille, Thejas, Koji]

We added a reinforcement bar at the back of the invar block which had the tilt issue.

The reinforcement bar was added to the backside rather than the side or front such that the DCPD housing does not interfere with the reinforcement bar.

Also, small amount of EP30-2 was added to the CM2 wire so that the repeated bend of the PZT wire cause the disconnection at the PZT.

Attachment 1: PXL_20230202_003156761.jpg
PXL_20230202_003156761.jpg
Attachment 2: PXL_20230202_003204058.jpg
PXL_20230202_003204058.jpg
  484   Sat Feb 4 03:16:10 2023 KojiOpticsGeneralOMC #4: One Invar block bonded with tilt

The attached photo shows the resulting bond spread.

 

Attachment 1: PXL_20230202_213114009.jpg
PXL_20230202_213114009.jpg
  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.

Attachment 1: PXL_20230202_002014960.MP.jpg
PXL_20230202_002014960.MP.jpg
Attachment 2: PXL_20230203_011618168.MP.jpg
PXL_20230203_011618168.MP.jpg
Attachment 3: PXL_20230203_011633873.jpg
PXL_20230203_011633873.jpg
  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.

Attachment 1: PXL_20230202_210750100.jpg
PXL_20230202_210750100.jpg
  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)

Attachment 1: PXL_20230204_072749311.jpg
PXL_20230204_072749311.jpg
Attachment 2: PXL_20230204_072744686.MP.jpg
PXL_20230204_072744686.MP.jpg
Attachment 3: PXL_20230204_073603041.MP.jpg
PXL_20230204_073603041.MP.jpg
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