40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
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ID Date Author Typedown Category Subject
  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.

  10   Mon Jul 23 17:15:14 2012 KojiCleanGeneralTalking with Margot

I consulted with Margot about the cleaning of the optics

  • Optics are considered as a clean object. Large dusts can be removed by ionized N2 flow etc.
  • Barrel of optics can be wiped with Acetone.
  • Optical surfaces are best to be cleaned by First Contact.
  • A peek mesh should be embedded in the first contact so that the First Contact sheet can be easily removed.
  • When peeling a F.C. sheet from a mirror surface, ionized N2 should be brown for discharging.
  • If there are residuals visible on the mirror surface, it should be removed by Acetone. Don't use alchols.
  • Use paper lens tissue for wiping as the lint free wipe can be eaten by Acetone.
  • In fact, All of the procedure is described in a certain document.
  • For a small amount, Margot can provide us a bottle of F.C. and some PEEK meshes.

Details of the Ionized N2 system

  • This N2 should have higher purity than 4N (UHP - Ultra High Purity). This means we should use 4N - UHP or 5N - Research Grade.
  • The ionized gun used in the clean room at Downs: made by Terra Universal.com
  • Flow path: N2 cylinder - Filter - Gun
  16   Mon Aug 13 16:59:11 2012 KojiCleanGeneralRoom Cleaning Log

Floor wiped with a wet wiper (Aug 13, 2012)
Floor wiped with a wet wiper (Aug 15, 2012)
Floor wiped with a wet wiper (Sep 25, 2012)
Air conditioning prefilter replaced (Sep 25, 2012)
Floor wiped with a wet wiper (Oct 01, 2012)
Floor wiped with a wet wiper (Nov 06, 2012) / ATF too
Floor wiped with a wet wiper (Jan 04, 2013)
Floor wiped with a wet wiper (Mar 23, 2013)
Floor wiped with a wet wiper (Apr 17, 2013)
Air conditioning prefilter replaced (Apr 17, 2013)
Floor wiped with a wet wiper (Jun 24, 2013)
Removing Vladimir's mess. Floor swept with a broom (Jun 26, 2013)
Completed removing Vladimir's mess. Floor swept with a wet wiper (Jun 27, 2013)
Air conditioning prefilter replaced (Sep 12, 2013)
Floor wiper head replaced. (Dec 10, 2013)
Floor wiped with a wet wiper (Dec 10, 2013)
Floor wiped with a wet wiper (Apr 1, 2014)

Air conditioning prefilter replaced (Dec 30, 2014)
Air conditioning prefilter replaced (some time in 2015...)

Floor wiped with a wet wiper (Dec 1, 2015)
Floor wiped with a wet wiper (Aug 23, 2016)
Air conditioning prefilter replaced (Aug 8, 2017) = 1 stock remains

  17   Mon Aug 13 17:01:35 2012 KojiCleanGeneralParticle Counts

Aug 13, 2012 / 0.5um 1000~2000/(0.1 cu ft) / 0.7um   400-600/(0.1 cu ft) by ATF particle counter (MET ONE 227A)

They are counts/(0.1 ft^3)! These numbers should be multiplied by 10 to know the particle "CLASS".

  20   Tue Sep 25 14:18:14 2012 KojiCleanGeneralParticle Counts

Particle counts

Before the prefilter is installed: 0.5um 1191cnts, 0.7um 346cnts

2:20 prefilter installed
2:25 0.5um 650 / 0.7um 255
3:00 0.5um 578 / 0.7um 99
4:00 0.5um 480 / 0.7um 102
5:00 0.5um 426 / 0.7um 76

They are counts/(0.1 ft^3)! These numbers should be multiplied by 10 to know the particle "CLASS".

  21   Mon Oct 1 16:06:55 2012 KojiCleanGeneralParticle Counts

1. It turned out that the particle counter MET ONE 227A at ATF shows
(particle count)/(0.1 ft^3)


This means that the numbers I saw previously should be multiplied by 10.
So the nominal class of the room was 5000.

2. As our GT-321s have no diffuser, I borrowed a diffuser from 227A.
The diffuser actually increases the count. We need to buy them.
All the measurments below are performed with the diffuser and calibrated in Count/ft^3.

3. Measured the particle level without the HEPA running.

With diffuser: [cnt/ft^3]

  GT-321 #1 GT-321 #2   227A
0.3um 152622 137511 -
0.5um  14706 14823   11860

Over Class 10000

4. The two HEPA fans are turned on at the speed "MED".

Basically no particles are detected in the HEPA booth.

With diffuser, inside of the HEPA booth:

  GT-321 #1 GT-321 #2  227A 
0.3um 0 0
-
0.5um 0 0 0

The particle level in the room (outside of the HEPA booth) is also improved

With diffuser, outside of the HEPA booth GT-321 #1:
0.3 um 18612
0.5 um   1728

5. The two HEPA fans are turned on at the speed "LOW".

Particle levels are still zero inside.

With diffuser, inside of the HEPA booth, GT-321 #1:
0.3 um 0
0.5 um 0

The particle level in the room (outside of the HEPA booth) is also improved
but the cleaning power for 0.3um seems degraded.

With diffuser, outside of the HEPA booth, GT-321 #1:
0.3 um 34488
0.5 um   1386

 

  45   Wed Dec 19 18:47:03 2012 KojiCleanGeneralFirst Contact Training with Margot

Steve and I visited Margot to have a training session for application of First Contact on optics.

- Make "thick" layer of first contact. It becomes thin when it gets dried.

- Apply more FC once a peek sheet is placed on the FC

- Wait for drying (~15min)

- Rip off the FC layer by pulling a peek tab. Make sure the ionized N2 is applied during ripping.

- Margot has a Dark Field Microscope. We checked how the dusts are removed from the surface.
There are many dusts on the mirror even if they are invisible. First Contact actually removes
these dusts very efficiently. Margot told us that even carbonhydrates (like finger prints) can be removed by FC.

  127   Tue May 14 19:06:00 2013 KojiCleanGeneralOMC Baking

The OMC is in the air bake oven now.

 

  361   Wed May 15 19:07:53 2019 KojiCleanGeneralWhat is this???

Suddenly something dirty emerged in the lab. What is this? It looks like an insulation foam or similar, but is quite degraded and emits a lot of particulates.

This does not belong to the lab. I don't see piping above this area which shows broken insulation or anything. All the pipes in the room are painted white.

The only possibility is that it comes from the hole between the next lab (CRIME Lab). I found that the A.C. today is much stronger and colder than last week. And there is a positive pressure from CRIME Lab. Maybe the foam was pushed out from the hole due to the differential pressure (or any RF cable action).

 

  368   Mon Jun 24 12:54:58 2019 KojiCleanGeneralHEPA BOOTH

https://www.airscience.com/purair-flow-laminar-flow-cabinets

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