NAOJ GW Elog Logbook 3.2
[Aso, Marc, Rishabh]
We removed the spare ETMY and put it inside its container.
To do it safely we first removed a front supporting pillar that has to be reinstalled.
Maybe because of that, it was first not possible to move the translation stage upwards (the right motor while looking from the input side was not moving).
After some up/down motion it could move slowly without issue.
We could not find the 3 screws to fix the container lid. We plan to manufacture new ones.
After discussing with Akutsu-san, I disassembled the Al frame on the optical table in front of the AC unit.
The optics (Nikon camera, some beamsplitters and other items) on the other end of the optical table (away from the AC unit) are still there since I have to discuss what to do with them with someone (who?).
Please feel free to use this table.
In labview, we now have average filtering implemented. So, we can average camera and power meter's data (using average order from 1-10) at the same voltage of LC.
Also, as a modification of 3319, we can now do several iterations of the same file and even fix the resolution of data that should be used from the file.
I removed the FP cavity from the cryostat in ATC in prepration for cabling work.
The folded cavity optical table is now very crowded (being used by Mitsuhashi-kun and myself).
I want to remove the aluminium frame and foil from the optical table in front of the air-conditioning unit. Is it acceptable?
I need to fix the electrostatic actuator that came off during assembly.
Since I could not find epoxy in NAOJ, I will bring it from KEK and finish the assembly once the actuator is fixed.
(We can't upload photos to the logbook. We should discuss how to maintain the logbook)
(log book went down around this time)
(it seems we cannot upload photos to logbook)
I cleaned the nodal support system components with help from Hirata-san.
During this work, the ethanol from one of the containers was used up.
Tabletop experiment of speed meter
Yohei Nishino & Munetake Otsuka
-Configuration
1)Laser -> 2)QWP -> 3)HWP -> 4)Convex lens -> 5)BS -> 6)HWP
-> 7)FR -> 8)Rotary Disc Shutter -> 9)HWP -> 10)AOM -> 11)Mirror
-> 12)Mirror -> 13)Convex lens -> 14)EOM -> 15)Convex lens
-> 16)FR
-Polarization mesurement after 15)Convex lens
Horizontal 27,3 uW with background 4.3uW
Vertical 4.7 uW with background 4.3uW
Without polarizer 32.9 uW with background 4.3 uW
-Beam profile after 15)lens
position x-width y-width
875mm 0.42mm 0.53mm
900mm 0.51mm 0.56mm
925mm 0.58mm 0.63mm
950mm 0.68mm 0.71mm
975mm 0.74mm 0.84mm
1000mm 0.82mm 0.84mm
Yohei Nishino & Munetake Otsuka
-Configuration
1)Laser -> 2)QWP -> 3)HWP -> 4)Convex lens -> 5)BS -> 6)HWP
-Optical power measurement
output of 4) : 473mW
output of 4) ->Polarizer @ 90 deg : 1.8 mW
output of 4) ->Polarizer @ 0 deg : 391 mW
output of 5) : 272 mW
output of 6) : 219 mW
-Optical component specifications
Extinction Ratio of Polarizer : 0.46% (=1.8/391)
Transmittance of 5)BS @ polarized light : 69.6% (=272/301)
-Configuration of wave plate
2)QWP : 24 + 0.4
3)HWP : 144 + 0.5
-Confirm 6) is really HWP @ 1064 nm
-Beam profile
-Firstly, tried to measure the beam profile with 2 ND Filters:-
beam profile has terrible modal noise, so change one ND filter to gradient shutter.
-output of 6) : beam diameter 1.0 mm
-output of 6) -> Faraday Rotator : 0.7mm with some modal noise
Tabletop experiment of speed meter
Yohei Nishino & Munetake Otsuka
-Configuration
1)Laser -> 2)QWP -> 3)HWP -> 4)Convex lens -> 5)BS -> 6)HWP
-> 7)FR -> 8)Rotary Disc Shutter -> 9)HWP -> 10)AOM -> 11)Mirror
-> 12)Mirror -> 13)Convex lens -> 14)EOM
-Optical power mesurement of 10)AOM
1st diffraction light 1.06 mW
Transmitted light 0.69 mW
while input light 1.81 mW
-Optical component specifications of 10)AOM
Diffraction efficiency : 60% (=1.06/(1.06+0.69)
-Configuration
9)HWP : 51
Function generator for 10)AOM : 40MHz 5V(0 to peak)
-Beam profile after 13)lens
position x-width y-width
700mm 0.29mm 0.38mm
750mm 0.28mm 0.20mm
800mm 0.33mm 0.34mm
850mm 0.49mm 0.60mm
Using data from the long polarization states generation of elog3308 I saved all the voltages required to generate a rotating HWP with 0.1deg error in ellipticity.
The 1st column is V1 and second column V2. They are sorted so that the HWP rotates from -90 to +90 deg.
The file is 'rotatingHWP.csv'
I set a monotor camera tentatively in the center room of TAMA at the request of the safety office. If the test operation was reasonable, I would set more cameras at some points.
Today, I disassembled the setup for cleaning.
I did not have the CAD drawing, so I winged the disassembly and only broke the electrostatic actuator.
The components are now on the optical table in plastic bags (fig. 2).
I will clean them and reassemble the setup next week (probably Wednesday).
I made double pendulum made by inverted pendulum and Roberts' Linkage.
So I measured the transfer function from IP actuator power to IP displacement and Roberts' Linkage displacement to check how it is.
Each set up pictures are attached(Fig1, Fig2).
IP displacement are measured by LVDT mounted on IP top stage.
Roberts' Linkage displacement are measured by photo displacement sensor.
Each transfer function are attached(Fig3, Fig4).
From Fig3 gain plot, I can realzed that common mode and differrential mode peak and characteristical dip.
I can also realized that points from Fig3 phase plot.
At 400mHz peak is IP yaw motion, and at 1Hz peak is Roberts' Linkage paw motion.
I mentioned about Fig4 lately.
We suspend Roberts' Linkage from IP top (image: Fig1, picture: Fig2). The parameters were as follows.
| high [m] | 0.4 |
| weight [kg] | 28.73 |
I also measured the power spectra with using Photo displacement sensor(Fig3). During measuering, we locked IP physically using meal fitting.
I attached the results (Fig4).
I can realized that there are two peak. These peaks are also from resonant frequency.
I thought it from difference between wire lenghts.
The optics are in the small desiccator (fig.2), and the pedestals and mounts are in a plastic box (fig.3).
I found some mirrors had scratches on them. In hindsight, I should have marked them. (Anyhow, it can be sorted later by the user.)
I will clean up the surrounding area after moving the optical table.
The option to choose a specified configuration from a pre-saved file has been added. As a result you can load the list of LC voltages required for any particular scenario.
[Shalika, Gabriella]
The setup was modified and two beam splitters were added (before and after LCs). The measurement to calibrate the beam splitters (both reflection & transmission) were taken as well (done without LCs).
What I did:
I fited the resuts of IP's resonant frequency to theoretical value.
The equation used for fitting was atttached.
f is IP's resonant frequency.
k_e is spring constant of IP's flex joint .
k is s anti spring constant.
g is gravity constant.
l is length of IP.
m_0 is mass of IP.
M is weight on IP.
From fitting, m_0 is 1.08 kg, k_e is 131 N/m, l is 2.48 m.
The results and fitting picture was as follows.
X-axis is weight on IP top, y-axis is IP's resonant frequency.
What we did:
We diagonalized the matrix of IP, and checked how much diagonalization was.
The matrix's values form LVDTs to imaginally L-axis and T-axis were as follows.
| L | T | |
| H1 | +0.20 | -0.04 |
| H2 | -0.07 | -0.12 |
| H3 | -0.09 | +0.13 |
The matrix's vakues from L-axis and T-axis to actuators were as follows.
| A1 | A2 | A3 | |
| L | -2.20 | +2.45 | +0.46 |
| T | +0.45 | +3.21 | -2.71 |
I measured the trasfer function from L,T to L,T respectively.
The pictures was attached.
I concluded it was good at some extend.
The measurement seems to go fine and is mostly finished.
However, because of the new failure of air conditioning the temperature and humidity increased quite a lot in TAMA.
It's about 30deg in main building and quite more inside clean room.
just for safety I turned off PCI laser.