NAOJ GW Elog Logbook 3.2
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.
In order to consider the effects of birefringence or double refraction in a uniaxial crystal like sapphire or calcite, I personally wrote a document
http://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=3519
to follow the discussions in CQG 27 185015 (2010).
In short:
(1) The KAGRA ETM with 0.05-degree wedge at its AR side would not spilt optical beams due to birefringence or such splitting is ignorable even if the c-axis of the sapphire substrate is tilted in no more than 2 degrees to the HR surface; the effect is indeed small, as the difference between ordinary and extraordinary index of refractions of sapphire are small.
(2) I found the CQG paper mentioned above contained at least two typos in its eq. (7), as indicated in my document.
Be careful that I don't mention any effects from polarization mixture. A uniaxial crystal would be used as a wave plate, and that means, it will mix two electric-field vectors in a propagating light beam through the crystal if its c-axis is tilted. The phase modulation in the light could be converted to amplitude modulation and vise versa due to the effects...
Member: Takahashi, Ohishi, Ishizaki, Barton, Doi
[April 23 AM]
- Measured particles (4-10/L@1F, 29/L@2F).
- Removed lapping for the chamber.
- Wiped the floors by a mop.
- Wiped the chamber by wet cloth.
- Measured particles (2-4/L@1F, 11/L@2F)
Member: Takahashi, Ohishi, Ishizaki, Barton
[April 21 AM]
- Checked the status around the MCE chamber.
- Found the alert for oxygen (19.0%).
- Went out of the tunnel.
- Calibrated the sensor.
- Reentered to the tunnel to measure the oxygen density (20.5-20.7%).
[April 21 PM]
- Cover the sheet over the clean booth to avoid drop water.
- Lapped the MCE chamber.
[April 22 AM]
- Wiped the roof of the 2nd floor in the clean booth.
- Wash the 2nd floor by city water using a water gun.
- Dried out the 2nd floor by wiping.
[April 22 PM]
- Wash the 1st floor by city water using the water gun.
- Wiped the roof of the 1st floor.
- Wash the 2nd floor by pure water using the other water gun.
- Wash the 1st floor by pure water using the water gun.
- Dried out the 2nd floor by wiping.
- Dried out the sheet by wiping.
- Measured particles (64900-77800/L@1F, 122200/L@2F)
- Turn on the fan of filters.
Torii-san made another measurement on VB with his improved setup. So I calculated the BRDF according to his result.
I also did a first "real" measurement with the JASMINE scatterometer on a SB plate. I put the results in the attachment.
I was asked by the JASMINE people to tell them how to use the scatterometer. Maybe in the next time I will have to teach it to some of their students.
I upload three drawings.
As Akutsu-san pointed me to this, I should add that the strange curve of PRM(horizontal) is maybe due to the high peak of its transfered vibration noise at around 0.5Hz.
It seems that I first have to dump this peak to become a more realistic result...
I found the error in my calculation which was actually not really an error but a non sufficient precision of the calculation software. I made the calculations again using Mathematica with higher precision.
The results can be seen in the attached graphs. I uploaded the results for each mirror and type of vibration (horizontal/vertical).
As Akutsu-san pointed me to this, I should add that the strange curve of PRM(horizontal) is maybe due to the high peak of its transfered vibration noise at around 0.5Hz.
It seems that I first have to dump this peak to become a more realistic result...
I finished (for now) to calculate the up-conversion of suspended PRM, BS, and SRM mirrors.
However, it seems that I have to improve my calculation procedure as I got strange results when the spectral density falls below 10^(-15) m*Hz^(-1/2)...
I upload a picture of the results for all three mirrors in case of a horizontal vibration.
Writting the theory part of my paper makes progress (although probably it is a bit overloaded..).
However, I am still thinking of what should be the actual content of my manuscript.
In particular, Iam not sure whether I should report also on the measurements that I have done or whether I just give the results of the calculations...
Report on some of the main points given in the meeting:
- Cryo-payload-integration meeting will be held only once per month in this FY
- NAOJ groups should attend the meeting (VIS, AOS,...); respective requests will be given later maybe
- No clean booth this FY because of financial problems
- NAOJ should consider to construct a clean booth on the second floor
- one payload will be purchased this year (have to!), then checking; others next year
- surface polishing of sapphire-sapphire ear connection area by impex not sufficient (P-V=633nm/2 is required but 1.4*633nm measured by Tatsumi-san)
- Other black material: oxidized, rough copper surface.
The zip-file seems to be password protected.
May I ask for the password?
See the attached PDF file
The zip-file seems to be password protected.
May I ask for the password?
In order to write my paper/report on the calculation that I have done on scattering of the mirrors, I asked Hirose-san to give me the PSD of the BS.
He kindly responded and gave me the data quickly so that I can now derive the rms surface roughness and so one for further calculations.
I think these kind of information might be interesting for other application too.
The vacuum chamber to be used for the macroscopic quantum measurement experiment was delivered to NAOJ and now stored temporarily at the TAMA center room. It will be moved to Tohoku University within April.
The photos are here:
(Sorry for the late entry)
The cryostat was installed at the ATC on Mar. 26th (Thu).You can see the photos here:
The cryostat was just put in place, but no test was performed at this time because they want to bring it back in a few weeks. Here is the reason. At their factory, the company performed a cooling test, but they could not cool the sample stage as quickly as they thought. There must be something wrong with the system, but they did not have time to track down the issue. Therefore, they delivered the sytem once to the NAOJ. But they need to bring the system back to their factory to fix the problem.
In any case, the cryostat will be in the ATC at least for a few weeks from now. So we can use it as just a vacuum chamber. We are planning to perform a rough leak test of the geophone canisters using this "vacuum chamber".
Today, I connected the vacuum pumps and wired up them. Now the pumps (scroll + turbo) are running. At the time I left the lab., the vacuum level was about 1e-1 Pa. I plan to leave the pump running for a while. The photos of today's vacuum work can be found here:
Last week, Torii-san measured the backscattering properties of DLC and soot of a candle distributed on an Aluminum surface.
I have now calculated the respective BRDF. The DLC backscatter is now symmetric and shows a sharp and strong peak (>100 1/sr) for its specular reflection. The wide-angle scattering is similar to MV from A.
The soot shows no specular reflection peak but a more or less equally distributed scattering also at wide incident angles. The wide-angle scattering is 1.5-2 times the one from MV.
(for more details, just ask me)
I finally succeeded in calculating the up-conversion of seismic noise in the Kamioka-mine with both Mathematica and Scilab.
I just wanted to follow the thoughts from Flanagan and Thorne which give a procedure how to do the up-conversion from a given spectral noise distribution. Anyway, I also did the explicite calculation by using the time-dependent noise data from the Kamioka mine from Sakakibara-san.
Both calculations are consistent with each other.
Now, I only need the transfer functions for the various devices on which I did scattering/noise calculations to complete them.