NAOJ GW Elog Logbook 3.2
June 11
1) Clean the floor of clean booth.
2) Open the chamber.
3) Adjust the height of breadboard. The height was set to 490mm +/- 1mm from the base plate.
4) Measure the position of the breadboard by the straight edge and the pendulum. The position was deviated by -1.0mm, -1.75mm from the center of the chamber.
June 12
1) Measure the rotation of the breadboard by the straight edge and the pendulum. The position of support bolt was on the Y line within +/- 0.5mm.
2) Pick up some parts from the bottom of chamber. We found M10 long bolt, Al foil, I-bolt, and CCP base.
3) Close the chamber.
I acquired 3 minutes of the AC noise in the following conditions;
- pump off
- probe on
- front door closed
- various lock in integration time constants;
As shown in the plot , the higher the time constant, the lower the noise.
But we have to choose it depending on the total acquisition time, for example we cannot spend a week to acquire a surface map.
I report the values:
|
timeconstant (ms) |
Noise std (microV) |
| 10 | 47 |
| 30 | 14 |
| 100 | 18 |
| 300 | 9.5 |
| 1000 | 5.2 |
We remind the specification of the system says between 5 and 25 microV at time constant: 100ms; and chopper frequency: 380Hz.
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Then we switch off the HeNe probe and measure the noise of the photodetector with 100ms time constant.
The photodetector noise standard deviation is 0.8 microV (see the histogram below) and it includes the detector noise and the lockin noise
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For absorption of 22% we have about 350mV AC signal at 30mW pump power;
The signal should be at least 2 or 3 times the noise (18microV * 3);
For 12ppm we expect 19microV of AC signal at the same pump power (30mW)
This means that a pump power of 100mW might be sufficient to see a good signal for 12ppm. It follows that we need 10W to see absorptions of 0.1ppm
I tuned the lockin gain to have a better resolution for little signals.
I acquired 3 minutes of noise for different modulation frequencies, in the following conditions:
- Probe ON;
- Pump OFF;
- Front door closed;
- Lockin time constant 100ms;
I made an histogram for every acquisition and I computed the standard deviation in order to find the best chopper frequency.
The lowet value of the noise standard deviation is at 430 Hz modulation frequency. The second best value is for 480 Hz, as used previously. The highest noises are at multiples of 50 Hz, as expected.
Abstract: we did a test installation of an oplev's pillar to the tunnel.
Workers: Uchiyama and Akutsu
The test installation has been done around (1) PR3 chamber, (2) IFI chamber (for IMMT2 mirror), and (3) MCF chamber (for MCo mirror).
For all cases, the bolt holes on the floor are all dirty, and the M24x130 bolts are hard to fit to them without cleaning the bolt holes; even after the cleaning, it was so hard,
so ratchet socket wrenches are used to screw. Actually we didn't have M24 washers today, so the legs have not been fully fixed.
(1) for PR3,
It is known that the pillar and the chamber's hinge will mechanically interfer, and the inconvenient fact was confirmed. We just slide the pillar a little from the planned location, and found a so-so place, but not know wether the optical table on the pillar can be installed or not. When the pillar stands, the top surface is almost horizontal without shims (shown by a whater leveler), and this means the floor surface here and the pillar's upper and lower surfaces are well manufactured.
(2) for IMMT2 mirror
Not much mechanical intereferences, but one concern is space between a barrelhead attached to a gate valve between MCF and IFI chambers. Still the bolts were hard. When the pillar stands, the top surface is almost horizontal without shims (shown by a whater leveler), and this means the floor surface here and the pillar's upper and lower surfaces are well manufactured. The height from the top surface to the beam line is measured to be 112.5 mm (the beam line height is just estimated from the chamber structure). Then the oplev beam height from the optical table on the pillar can be estimated 112.5 - 27 = 85.5 mm. The expected beam height was 85.85~85.9 mm, so it could be in the tolerant range.
(3) for MCo mirror
Not much mechanical intereferece, but one concern is space between a reducing flange and the pillar. Still the bolts were hard. Unfortunately, the floor surface for the pillar is not so good, and we need two pieces of shims to make the top surface horizontal. The height from the top surface to the beam line is measured to be 115 mm (the beam line height is just estimated from the chamber structure), which should be the same as the one arund IFI chamber, but now it is obvious to have 2.5 mm difference. This difference would be a little bit large if you take into consderaton about measurement errors. Then the oplev beam height from the optical table on the pillar can be estimated 115 - 27 = 88 mm. The expected beam height was 85.85~85.9 mm, so it could be a little bit larger than my expectation, but can be tuned.
I got the two-dimensional map of the BS from Hirose-san.
I will try to implement these data into the "LightTools" software in the next days.
At the same time, I tried to fit the one-dimensional PSD with the K-correlation model with only limited success.
It seems that this particular model is not suitable for the data...or the data aren't enough.
From the map it should also be possible to calculate the two-dimensional PSD and to fit these data instead of the one-dimensional one.
I would like to try these calculations also during the next days to see how far I can use the PSD for the scattering Paper I am now writing.
The laser for the JASMINE scatterometer is now focussed on the sample.
I used a lens with f=200mm; the size of the focal point is now 0.25 - 0.3 mm.
Measurements can again be taken.
I will do some test measurements tomorrow on a Titanium sample.
Finally Tatsumi-san gets the (usable) flexi circuit prototypes for OSEMs, and he gave them to me. I firstly check whether the soldering can be done, and the results so far are good.
An oplev's covering box prototype is assembled. Needs more additive modifications.
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.
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).
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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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...
To design the ASSEMBLE JIG,
I made measurement of flag thickness as attached.
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:
- New LED holder with TSTS7100 and new PD holder
- Old LED holder with OP232 and new PD holder (NOTE!)
- 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.
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.
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.
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.
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).
[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 and (prototype) flag base were delvered as attached file.
By using these parts I will try to adhere.