AC noise

 I measured the AC signal to estimate the noise in the following conditions:

No sample installed ;

Chopper frequency: 478 Hz ;

Lock-in time costant: 100 ms ;

Tuned to maximum DC signal ;

Front door closed ;

Motors moving but time wait 500 ms ;

 

Measure are taken in 3 different situations

 - Pump open at 30mW --> figure empty20150612.jpg ;

 - Pump  closed --> figure emptyclosed20150612.jpg ;

 - My voice singing around 478 Hz like here --> figure manuelvoice478hz.jpg ;

I measured 60 microV with silent, and 2.2 mV with acustic noise at chopper frequency.

 

The manual  says, at 380 Hz and with motors not moving, the noise is between 5 and 25 microV.

I will make measurement for many chopper frequencies and look for the minimum.

Spectrophotometry of two reference samples

By using spectrophotometer (Shimadzu SolidSpec 3700) at NAOJ ATC

transmissivity and reflectivity of the reference samples were measured.

From these measurements, absorption value can be obtained.

SURFACE SAMPLE:    Newport FRQ-ND02          22.0%

BULK SAMPLE:            Schott glass  NG-12         37.5%     ---> 37.5% / 0.36 cm = 104% /cm

Both of values are almost consistent with catalog spec. (22.2% and 116% /cm).

Glueing test of MasterBond EP30-2

I did the following things.

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[ Mixuture ]

EP30-2 (A) : EP30-2 (B) : borosilica = 10 : 1 : 0.55 = 5 g : 0.5 g : 0.275 g

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[ Cure schedule ]

24 - 48 hours        at 75 Fdeg = 21 Cdeg

2.0 - 2.5 hours      at 200 Fdeg = 93 Cdeg

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Test 1: Cure Testing

Provide heating by hot plate. Set the temperature to be 90 Cdeg (~200 Fdeg).

Leave the glue for 15 minutes. After the heating, cool it for 1 minute.

Because it is smooth and hard, it is a well-mixed batch.

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Test 2: Glue flag and flag base

After the test 1, I made glueing two sets of (dummy) flag and flag base.

One is heated at 90 Cdeg for 3.5 hours. Another is placed at room temperature (~24 Cdeg).

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iKAGRA AS port BRT design

Uploaded a draft of the design document for the iKAGRA AS port BRT (in Japanese)

http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=3624

I and Michimura-kun also had a skype meeting on how to take care this task...

Flag thickness measurement

To design the ASSEMBLE JIG,

I made measurement of flag thickness as attached.

OSEM preliminary test with a new test bench

OSEMs are preliminarily tested with a new OSEM test bench in a non-clean environment. The OSEM's LED and PD are operated by a test circuit (not an actual satellite box, but I and Okutomi-kun have just copied requred parts...)

The conbinations under test are:

1. New LED holder with TSTS7100 and new PD holder
2. Old LED holder with OP232 and new PD holder (NOTE!)
3. Old LED holder with OP232 and old PD holder (NOTE)

NOTE: the "old" LED holder cannot hold a lens with the same manner as the ones used in TAMA300 SAS prototype now, as it is revealed that the adhesive of lens to the "lens holder" inside the LED holder cannot be usable in vacuum. I just make the lens holded somehow....... so the distance from the LED and the lens are changed. However, from the rough measurement of beam profile of light of the ones, I got impression that such a change of positions doesn't have effects on the performance... (preliminary)

What to be confirmed is the linear range. I'd like to compare the range with the one used in TAMA300 SAS prototype.

So far the linear range are almost all the same.

Obviously when the linear range is such, we don't need to use such a large area photodiode; it is too large and hard to fit new and old designed PD holder. A small aperture PD would have smaller capacitance, and that makes the cricuit easliy stabilized.

... and 4. Plot of data by Sekiguchi-kun for TAMA-OSEMs; the data's range differs from our setup so I just lineary scaled the vertical axis. It appears that the linear range would not change.

Outgassing results of VB and MV

Regarding the Doughnut Baffle, the two promising candidates for a very good absorption/scattering coating have been tested for their ultra-high vacuum compatibility.

The results show that VB has better UHV capabilities then MV. Especially water seems to be highly abundant on the surface of MV.

Replacement of the breadboard in MCE

Member: N. Ohishi, H. Ishizaki, M. Barton, R. Takahashi

May 26
Checking condition of the clean booth at 1530-17:00 by Takahashi.
1) Turned on all (16) filters. 4 filters had been working before.
2) Hirose-san measured particles by the large counter. I measured particles by the small counter too. Number of particles was 5/L just after turnung on the filters. Humidity was 80.5%.
3) Hirose-san measured particles continuously during I walk around.

May 27
Replacement of the breadboard (1).
1) Cleaned the floor of the clean booth by the vacuum cleaner and the mope.
2) Opened the chamber.
3) Moved the optical bench into the clean boooth by the jib crane.
4) Extracted the suspension from the chamber and put it on the optical bench.
5) Extracted the breadboard. Up-down movement of the crane (chain block) is very slow.
6) Rapped the breadboard.

May 28
Replacement of the breadboard (2)
1) Cleaned the floor of the clean booth by the mope.
2) Cleaned inside the chamber by the vacuum cleaner, the wet wiper, and the dry cloth.
3) The SUS blocks were stacked after first disassembling. Since the guid rods are inside the MCF chamber, we don't use them. The crane can not move to ransverse direction. This is a problem.
4) Unpacked the renewaled breadboard and installed it into the chamber.
5) The breadboard extracted was enclosed by the wood box.
6) Rapped the suspension with decicant.
7) Closed the chamber.

Oplev Reciever

Now a prototype of the oplev receiver

http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=3562

is well assembled. Note that the QPD circuit in the photograph below has a wrong connector, and should be modified soon.

MCE Breadboard Replacement

27th-28th May,

Takahashi-san, Mark-san, Ishizaki-san, and Ohishi changed MCE breadboard.

Due to the unexpected stack cleaning work, surface level adjustment of the MCE board was postponed to 11th-12th Jun.

Inside the cleanbooth, humidity was  - 80% but cleanness was good -ISO class 4.

Optical bench was carried into the booth.

Attached pictures were taken by Koichiro (an Olympus camera equipped to NAOJ Kamioka branch).

Calibration with standard samples

[SURFACE SAMPLE]

Newport FRQ-ND02

Absorption   22.2%  at 1064 nm

pump power damage threshold 40mW

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Type UV Fused Silica Metallic ND Filter   ---> Inconel coated fused silica substrate

Optical Density                    0.2 at 633 nm 

Diameter                              1.0 in. (25.4 mm)

Thickness                            0.118 in. ( 3.0 mm)

Material                                UV grade fused silica

Surface Quality                    60-40 scratch-dig

Surface Flatness                  less than 1 lambda at 632.8 nm over the clear aperture

Wedge                                  less than 3 arc min

Wavelength Range              350 - 2000 nm

Diameter Tolerance             ±0.25 mm

Thickness Tolerance            ±0.25 mm

Clear Aperture                      central 80% of dimensions

Damage Threshold               30 W/cm2 CW, typical;

                                              not recommended for pulsed laser use

Angle of Incidence                0 degree

Transmission                        63.1 % at 632.8 nm

Optical Density Tolerance    ±7%

Chamfers                              0.25-0.76 mm face width

Chamfers Angle/Tolerance   45 ±15 degree

Cleaning                                Non-abrasive method, acetone or isopropyl alcohol on lens tissue recommended

[BULK SAMPLE]

Schott glass NG-12

Thickness                                      3.6 mm

Absorption rate                              116% /cm

Refractive index                             1.48 at 1014 nm

Pump power damage threshold     100 mW

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Absorption = 1.16 /cm * 0.36 cm = 0.418 = 41.8%

Dummy flag for glueing test

Dummy flag and (prototype) flag base were delvered as attached file.

By using these parts I will try to adhere.

Hotplate for glueing

Hotplate                              AsOne      ND-1

Radiation thermometer       Fluke        62 MAX+

After the delivery, I made operation tests as an attached file.

Assy of Category A viewport windows with flange adapters (2pcs)

See (in Japanese)

http://gwclio.icrr.u-tokyo.ac.jp/lcgtsubgroup/inoutoptics/2015/05/category-a-viewport-window-2.html

Pump beam course alignment

I made course alignment of the pump beam as shown in the attached file.

Then at final end of the laser I checked the laser power fluctuation.

Within a hour there is no obvious drift.

I wll make calibration test.

Installation of Finshig rod to KAGRA Bottom Filter

On May 21, I and Hirata-san assembled some Fishing rods and installed them to the KAGRA Bottom filters.
I summarized this below;
http://gwclio.icrr.u-tokyo.ac.jp/lcgtsubgroup/vibrationisolation/2015/05/installation-of-finshig-rod-to-kagra-bottom-filter.html

Flexi circuits

The current status of the flexi circuits for OSEMs are here:

http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=3570

Mechanically it appears nice, but no holes for soldering... I'm waiting for the alternatives.

The next step would be measuring the outgassing rate at KEK.

OSEM LED test

I've seen light proflies of LED candidates for OSEM: OP232 and TSTS7100, and found the latter is better in terms of the uniformity, which would be important parameter for OSEM.

Each LED is set in the LED holder of an OSEM, and I did the check above w/ and w/o the additional lens, which was said to help collimation of light; it looks helping situation somewhat.

When test benches are prepared, I can test them as OSEMs.

Laser Power Stability

Measurement of the laser power stability for optical absorption system.

I found the stability is less than 1% in a hour.

up-conversion with transfer functions

I have written a program to overcome the problems with the Flanagan-Thorne procedure for transfer functions having very strong resonances by using time series of seismic noise.

Still, the results are not as sufficient as without these resonances but better than the procedure from Flanagan and Thorne. I uploaded a graph.