NAOJ GW Elog Logbook 3.2
See (in Japanese)
http://gwclio.icrr.u-tokyo.ac.jp/lcgtsubgroup/inoutoptics/2015/05/category-a-viewport-window-2.html
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.
I summarized this below;
http://gwclio.icrr.u-tokyo.ac.jp/lcgtsubgroup/vibrationisolation/2015/05/installation-of-finshig-rod-to-kagra-bottom-filter.html
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.
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.
Measurement of the laser power stability for optical absorption system.
I found the stability is less than 1% in a hour.
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