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KAGRA MIR (Absorption)
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ManuelMarchio - 14:10, Tuesday 12 July 2016 (270)Get code to link to this report
Dust particle counting

Since one possible explanation of the  noise is dust, I used the particle counter to quantify the dust.

Instrument name: MET ONE Airborne Particle Counter HHPC6+

Acquisition time: 10 minutes

Volume: 28.36L

 

Inside the clean booth of Tama central room.

Size

cumulative

counts/L
0.3um 199489 7034
0.5um 15086 532
1um 2018 71
2um 740 26
5um 114 4
10um 57 2

Almost the same order of a normal room. Indeed I realized that the fans of the clean booth were OFF since a couple of month ago, when I checked whether the acoustic noise was important.

 

I switched ON the fan and wait half an hour

Size

cumulative

counts/L
0.3um 943 33
0.5um 65 2.3
1um4 4 0.14
2um 1 0.03
5um 0 0
10um 0 0

 

After one hour

Size

cumulative

counts/L
0.3um 139 5
0.5um 16 0.5
1um 1 0.03
2um 1 0.03
5um 0 0
10um 0 0

 

The morning after I came inside the clean booth and run the count

Size

cumulative

counts/L
0.3um 1018 36
0.5um 83 3
1um 3 0.1
2um 2 0.07
5um 0 0
10um 0 0

So it looks that an entire night doesn't clean the air much more than an hour.

 

Moving very gently I repeated the count

Size

cumulative

counts/L
0.3um 195 7
0.5um 21 1
1um 2 0.07
2um 0 0
5um 0 0
10um 0 0

I think there is some dust on the everything, so when I move the air, the dust flies and make the count higher.

 

Then I moved the particle counter in the small clean booth on the small optical table that is used for gluing work

Size

cumulative

counts/L
0.3um 2 0.07
0.5um 0 0
1um 0 0
2um 0 0
5um 0 0
10um 0 0

Very clean...

 

And then I went to clean room of ATC

Size

cumulative

counts/L
0.3um 6 0.2
0.5um 0 0
1um 0 0
2um 0 0
5um 0 0
10um 0 0
Images attached to this report
270_20160712070453_img20160712134444.jpg 270_20160712070501_img20160711182333.jpg 270_20160712070507_img20160711180128.jpg 270_20160712070514_img20160711174356.jpg
R&D (FilterCavity)
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DaisukeTatsumi - 11:22, Tuesday 12 July 2016 (269)Get code to link to this report
TAMA Faraday Isolator Information

I got some information about TAMA Faraday Isolator from Takahashi-san.

I upload these files here.

Non-image files attached to this report
R&D (FilterCavity)
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EleonoraCapocasa - 00:37, Tuesday 12 July 2016 (234)Get code to link to this report
Filter cavity end mirror control

In the past days I have implemented the control of the end mirror of the filter cavity, following what was already done for the input mirror.

The transfer functions of the mirror motion, measured injecting white noise (with amplitude 3 V) in each degree of freedom, are plotted in the first figures of the attached document. In figure 4,open loop transfer functions are shown. In the last figures the comparison between the spectra with closed and open loops has been plotted.

Non-image files attached to this report
KAGRA MIR (Absorption)
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ManuelMarchio - 02:13, Monday 11 July 2016 (268)Get code to link to this report
Noise investigation - Bulk calibration factor when moving the detection unit

I made a scan of the bulk reference sample for many positions of the detection unit as I did in this post for other samples.

The position closest to the sample is 34mm, which is the usual position. Other positions are gradually further from the sample.

Modulation reference is from the chopper at 430Hz. Pump power is 30mW before the sample.

 

Plot1 shows the scan of the sample for different positions of the detection unit. AC signal

Plot2 shows the scan of the sample for different positions of the detection unit. AC signal / DC

For each scan, I took the point at which the calibration value is taken (3rd mm of the scan) and I took 10 minutes of data to check how the noise looks like with a large signal.

Plot3 shows  the calibration signal and noise (Y/DC vs X/DC) for each detection unit position.

Plot4 is a zoom of Plot3 

 

The following table is a summary of the values.

    

position AC DC Phase R
(mm) (V) (V) (°) (W-1)
34 0.12368±0.00087 4.87±0.02 115.70±0.09 0.728±0.006
30 0.1124±0.0015 4.24±0.02 113.35±0.11 0.76±0.01
25 0.095±0.001 3.78±0.02 112.21±0.12 0.725±0.009
20 0.089±0.001 3.31±0.02 109.76±0.12 0.77±0.01
15 0.0983±0.0008 3.56±0.02 109.1±0.1 0.792±0.008
10 0.0538±0.0006 2.05±0.02 109.01±0.12 0.75±0.01

Error values are the size of the clouds of points on the XY plane (standard deviations)

I notice that

 - the calibration factor (R=AC/DC/abs/Power) doesn't change more than 10% when moving the detection unit and doesn't show a clear trend

 - the noise on the XY plane is more on the AC value rather than on the Phase value (in other words the cloud is squeezed )

 - both the AC and DC get smaller when putting the detection unit further.

 - the measurement at 10mm is not reliable because the reflection of the probe on the prism after the sample was on the boundary of the prism.

Images attached to this report
268_20160710180256_plot1scan.png 268_20160710180419_plot2scan.png 268_20160710183823_plot3scan.png 268_20160710183834_plot4scan.png
KAGRA MIR (Absorption)
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ManuelMarchio - 00:17, Monday 11 July 2016 (267)Get code to link to this report
Noise investigation - Sapphire sample noise

I placed back the magnetic translation stage and measure again the noise of the small sapphire sample. 

I took the measurement in two cases: with and without the small sapphire sample.

Acquisition time: 10 minutes, Rate 100ms, demodulation with the lockin internal oscillator frequency 420Hz.

Plot1 shows the 2D plot of the AC signal from the lockin after demodulation, divided by the DC.

Plot2 is a zooming of the first plot, the circles are centered on the mean of the signal over all the acquisition time and have a radius equal to the standard deviation.

It looks the system is noisier without the sample, this makes me think that vibrations of the sample don't make a lot of difference. I have the idea that most of the noise comes from the dust, and it depends on how we move the air during replacing of the sample or working inside the box.

Images attached to this report
267_20160710171657_plot1.png 267_20160710171704_plot2.png
KAGRA MIR (Absorption)
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ManuelMarchio - 00:57, Wednesday 06 July 2016 (266)Get code to link to this report
Comment to Noise investigation - changing the detection unit position (Click here to view original report: 259)

The signal that I get with the oscilloscope comes from Lock-in CH1 OUTPUT. It is much higher than the signal recorded by the vi (the AC signal in entry 252, for example).

I read the sr830 lock-in  manual and I found that the CH1 OUTPUT voltage is proportional to the AC signal according to the following formula:

Output = (signal/sensitivity - offset) x Expand x 10 V

The Expand factor is 1, the sensitivity is 1mV, as we can see in the picture of the front panel.

So in the case of signal = 15uV , for example, I get Output = 150mV, a factor 10^4 higher

Images attached to this comment
266_20160705175507_img20160705160531.jpg
R&D (FilterCavity)
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ManuelMarchio - 16:16, Monday 04 July 2016 (265)Get code to link to this report
Comment to Working Log 2016-06-30 (Click here to view original report: 264)

[Manuel, Tatsumi]

We checked the wire connections for the coils. The pictures show the order of the wire connections on the suspension, and outside the tank.

Images attached to this comment
265_20160704083450_coilseroom2.jpg 265_20160704083555_coilseroom1.jpg
R&D (FilterCavity)
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DaisukeTatsumi - 16:46, Thursday 30 June 2016 (264)Get code to link to this report
Working Log 2016-06-30

[WORKERS]   Tatsumi, Takahashi, Manuel, Eleonora

(1) At TAMA south end room (EM2 tank)

* Install four coils.

* Connect in-vacuum cables for the coil

   Manual checked the cable connections. He will report soon.

 

(2) At TAMA center room (BS tank)

* Open the BS tank

* Remove the suspension with BS mirror

* Close the tank

 

Tatsumi will glue magnets on BS mirror in the next week.

And then we will install the mirror to the BS tank.

Comments related to this report
ManuelMarchio - 16:16, Monday 04 July 2016 (265)

[Manuel, Tatsumi]

We checked the wire connections for the coils. The pictures show the order of the wire connections on the suspension, and outside the tank.

KAGRA MIR (Absorption)
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ManuelMarchio - 14:29, Wednesday 29 June 2016 (263)Get code to link to this report
Calculation of the Probe beam size along the path trough different samples

I calculated the beam size of the probe beam using OSCAR.

I used the distances I measured and summarized in the first drawing.

The plots show the beam waist along the optical path, cyan area is the sample, vertical lines are the optical component of the experiment, black line is a mirror, cyan line is the f=50mm lens, orange line is the small sphere f=1.25mm

The last image is a comparison of the beam spot size at the PD position with the PD size in the 3 cases.

Images attached to this report
263_20160629060706_drawing1.png 263_20160629072656_smallbeamsizedetunit.png 263_20160629072710_tamabeamsizedetunit.png 263_20160629072725_kagrabeamsizedetunit.png 263_20160629072742_screenshotfrom20160629142551.png
R&D (FilterCavity)
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ManuelMarchio - 00:19, Tuesday 28 June 2016 (262)Get code to link to this report
Optical lever in PR tank

[Eleonora, Manuel, Tatsumi, Raffaele]

We took two viewport shelves from NM1 tank and installed them at the North-West and South-West viewports of PR tank.

We placed a laser and a mirror on the North-West viewport shelf and placed a PSD on the South-West viewport shelf.

We tried to send the laser to the front surface of the mirror. Since the mirror suspension is not centered on the stack, there is not enough space to get the reflected beam on the other viewport.  We decided to send the laser on the back surface of the mirror.

We placed to mirrors as show in the picture. Part of the laser is transmitted and goes to hit the tank wall. Part of the transmitted beam is reflected by the second surface and goes to hit the tank wall on the other side.

We closed the tank.

Then we checked the T, X and Y signals of the PSD using an oscilloscope. The optical lever looks working fine. We remark that the X signal (Yaw motion) is strongly dominated by an oscillation at about 1Hz.

Images attached to this report
262_20160627171741_screenshotfrom20160628001058.png
R&D (Cryogenic)
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SimonZeidler - 19:27, Friday 24 June 2016 (261)Get code to link to this report
Vacuum test for viewports

I installed a viewport on the flanges of the cryostat to test its vacuum compatibility. Right now, it looks quite good. The turbo pumb is working well and the viewport seems to be fine. I will leave the system on over the weekend to see whether we can reach the target pressure of 4*10^(-4) Pa.

R&D (FilterCavity)
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DaisukeTatsumi - 15:56, Wednesday 22 June 2016 (260)Get code to link to this report
Coil related parts

(1) Wiring parts

See attached picture.

 Product Name  Manufacturer  Product No.
 Burndy Male pin  COSMOTEC  PAC16
 Socket contact (Large, Female)  COSMOTEC  SVC24
 BNC socket  Custom made  ---
 BNC connector  KYOCERA  BNC-R-F

 

 

 

 

 

(2) Coil support plates

  Drawing No. Length Qty. Will use for EM2
 Side   F14   53 mm   3   2
 Upper   F15-1   43 mm   6   1
 Lower   F15-2   38 mm   2   1
Images attached to this report
260_20160622084211_wiring.jpg 260_20160622085643_p6220001.jpg 260_20160622085653_p6220002.jpg 260_20160622085716_p6220007.jpg 260_20160627054235_mirrormagnet.jpg 260_20160627062820_bnc.jpg
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KAGRA MIR (Absorption)
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ManuelMarchio - 00:37, Wednesday 22 June 2016 (259)Get code to link to this report
Noise investigation - changing the detection unit position

Given the fact that a thick sample changes the optical path of the probe, I wanted to see how and why the noise level changes when I change the position of the detection unit. The detection unit is made by one flat mirror at 45°, a f=50mm lens, a reflecting sphere f=2.5mm, and the photodetector.

I turned OFF the chopper to avoid any possible vibration, I set the lock-in internal oscillator as reference frequency (demodulation) at 420Hz.

I connected the oscilloscope at the photodetector (to see the DC signal), and at the output of the lock-in amp (to see the AC signal *1e6). I took some quick measurements, for different positions of the detection unit. The DC has a repeatability of 0.2V, the AC measurement is very rough, just an average of the signal in 10s. Every time I moved the detection unit I had to realign the beam on the PD, tuning the position of the 50mm lens to maximize the DC. The position can be changed only by 35mm, the length of the micrometer screw.

In the following table, there are the DC and AC values at different positions and for different samples. A higher position value means the detection unit is closer to the sample. Hence, 0mm is the furthest point where I could place the detection unit. To move it more it's necessary to unscrew the unit from the board.

I used three samples: the Sapphire small sample diam 1.5" x 5mm, the Sapphire Tama-sized  sample diam100mm x 60mm, and the glass KAGRA-sized sample.

    No sample   Small sample   Tama-size sample   KAGRA size sample
Position   DC AC   DC AC   DC AC   DC AC
(mm)   (V) (mV)   (V) (mV)   (V) (mV)   (V) (mV)
34   7.4 ~100   6.9 ~140   8.5 ~500   8.6 ~1100
30   6.8     6.4 ~100   8.5 ~500   8.6 ~900
25   5.8 ~80   5.4 ~110   8.5 ~400   8.6 ~800
20   4.9     4.6 ~90   8.0 ~150   8.6 ~900
15   4.4 ~80   4.0 ~100   7.4 ~120   8.6 ~900
10   4.0     3.6 ~90   6.6 ~115   8.5 ~600
5   4.4*     3.6 ~80   5.9 ~80   8.5 ~400

Looking at those data, I can say:

  • the DC decreases when the unit is placed further. This is reasonable considering the finite size of the PD and the divergence of the beam.
  • In the case without any sample, when the unit position changes, the AC noise level doesn't change a lot.
  • In the case with the small sample, when the unit distance increases, the AC noise level does decrease, maybe proportionally to the DC.
  • In the case with the Tama-size sample, when the unit distance increases, the AC noise level changes a lot, compared to the DC.
  • In the case with the KAGRA-size sample, when the unit distance increases, the DC is pretty constant and the AC noise level changes a bit.

The hypothesis I have in mind is that the probe spot size makes an important role when compared to the detector size.

I will use my simulations to try to reproduce the behavior shown in those measurements and try to find an  explanation.

Images attached to this report
259_20160621173446_img20160620162620.jpg 259_20160621173453_img20160620162651.jpg 259_20160621173459_img20160621150056.jpg 259_20160621173505_img20160621150657.jpg 259_20160621173529_img20160621164924.jpg
Comments related to this report
ManuelMarchio - 00:57, Wednesday 06 July 2016 (266)

The signal that I get with the oscilloscope comes from Lock-in CH1 OUTPUT. It is much higher than the signal recorded by the vi (the AC signal in entry 252, for example).

I read the sr830 lock-in  manual and I found that the CH1 OUTPUT voltage is proportional to the AC signal according to the following formula:

Output = (signal/sensitivity - offset) x Expand x 10 V

The Expand factor is 1, the sensitivity is 1mV, as we can see in the picture of the front panel.

So in the case of signal = 15uV , for example, I get Output = 150mV, a factor 10^4 higher

R&D (General)
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DaisukeTatsumi - 16:43, Monday 20 June 2016 (258)Get code to link to this report
gravity acceleration measurement

Aoyama-san of National Institute of Polar Research warmed up the Iodine stabilized He-Ne laser.

But they found trouble on the laser.

Now we are waiting for the warming-up run

and for the stable operation.

We will check the laser in tomorrow morning.

Images attached to this report
258_20160620094303_p6200092.jpg 258_20160620094313_p6200093.jpg 258_20160620094323_p6200094.jpg
R&D (FilterCavity)
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ManuelMarchio - 10:45, Monday 20 June 2016 (256)Get code to link to this report
Comment to TAMA mirror installations were postponed. (Click here to view original report: 253)

I add some pictures of  tama PR and tama BS.

First picture (tamabs1.jpg) shows that three magnets are clearly absent, but regarding the bottom left one, it's not clear: maybe is still attached, or maybe it is lying in the inner plastic part of the coil.

Images attached to this comment
256_20160619104330_tamabs1.jpg 256_20160619104403_tamabs2.jpg 256_20160619104431_tamabs3.jpg 256_20160619104512_tamapr1.jpg 256_20160619104546_tamapr2.jpg 256_20160619104616_tamapr3.jpg 256_20160619104703_tamapr4.jpg 256_20160619104725_tamapr5.jpg 256_20160619105021_tamapr6.jpg 256_20160619105047_tamapr7.jpg 256_20160619105145_tamapr8.jpg
R&D (FilterCavity)
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ManuelMarchio - 18:18, Sunday 19 June 2016 (257)Get code to link to this report
Comment to TAMA mirror installations were postponed. (Click here to view original report: 253)

I add some pictures of  tama PR and tama BS.

First picture (tamabs1.jpg) shows that three magnets are clearly absent, but regarding the bottom left one, it's not clear: maybe is still attached, or maybe it is lying in the inner plastic part of the coil.

R&D (FilterCavity)
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DaisukeTatsumi - 17:40, Friday 17 June 2016 (255)Get code to link to this report
TAMA (dummy PR) mirror installation

Tatsumi and Takahashi successfully installed the mirror into PR vacuum tank.

Also one additional optical window was installed for Optical Lever system.

Instead of that, a turbo pump was removed from the port.

 

ToDo list:

* In-vacuum coil actuator cables are temporary connected to the panel fixed at the suspension frame.

We should check the connection later.

R&D (FilterCavity)
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DaisukeTatsumi - 11:23, Thursday 16 June 2016 (254)Get code to link to this report
(temporary) EM2 mirror installation

We installed an old PR mirror into EM2 vacuum tank.

In-vacuum cables were salvaged from TAMA SAS.

ToDo list:

ToDo list for EM2 suspension
Coil Swage the pins to the wires.
Coil support plate Takahashi-san will look for at KAGRA
BNC connector plate at the suspension frame Takahashi-san will look for at KAGRA
In-vacuum cables for coil We need to unscrew the flange for BNC connectors.
R&D (FilterCavity)
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DaisukeTatsumi - 17:01, Wednesday 15 June 2016 (253)Get code to link to this report
TAMA mirror installations were postponed.

(1) South end room / mirror installation

Because a stand-off came off the mirror, we postponed the installation to Thursday.

(2) South end room / Coil

Tatsumi has 20 of coils with bobin.

Pin connectors should be swaged to the coil wires. Takahashi-san has a swage tool and pins.

Tatsumi will make swage works tomorrow.

The pins will be connected to BNC connectors. Tatsumi cannot find the connector.

Takahashi-san will look for at KAGRA site in next week.

Coil support plates are also not found. We hope to find these at KAGRA.

(3) PR tank at center room

Stand-off for this mirror is also troubled. We will install the mirror on Friday.

We found that one pico-motor is missing for the suspension.

Takahashi-san installed the motor today.

(4) BS mirror

We checked BS mirror with opening the vacuum tank.

We found that all of four magnets came off the mirror. 

Glueing jig for TAMA BS is at KAGRA site. Takahashi-san will send it back in next week.

And then we need the glueing and installation work.

 

Manuel will upload some pictures. 

Comments related to this report
ManuelMarchio - 10:45, Monday 20 June 2016 (256)

I add some pictures of  tama PR and tama BS.

First picture (tamabs1.jpg) shows that three magnets are clearly absent, but regarding the bottom left one, it's not clear: maybe is still attached, or maybe it is lying in the inner plastic part of the coil.

ManuelMarchio - 18:18, Sunday 19 June 2016 (257)

I add some pictures of  tama PR and tama BS.

First picture (tamabs1.jpg) shows that three magnets are clearly absent, but regarding the bottom left one, it's not clear: maybe is still attached, or maybe it is lying in the inner plastic part of the coil.

KAGRA MIR (Absorption)
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ManuelMarchio - 19:43, Sunday 12 June 2016 (252)Get code to link to this report
Noise investigation

In last report, I showed that to fix tightly the samples to the board doesn't change the noise level. http://www2.nao.ac.jp/~gw-elog/osl/?r=247

I did other measurements in different conditions trying to understand where the noise comes from.
I plot the raw data AC (lockin Y vs lockin X) divided by the DC.
Plot1: Tamasize sample sit on blocks (already plotted in last report) makes more noise than the small sample, even dividing by the DC.
Plot2: Noise level (standard deviation) in two different days have a repeatability of about 10%.
Plot3: Both samples tightly fixed at the board using the new mirror mounts. Small sample makes more noise than the tamasize sample. I really dont understand this. Also the distribution for the small sample is strange, more points on the tails of the distribution.
 
I moved the detection unit 35mm further to check if the noise depends on the distance of the detection unit.
The detection unit is made by the focusing lens (f = 50mm), the smal reflecting sphere (f = 1.25mm) and the detector.
 
Plot4: at a further position the noise is less (I expected the opposite)
Plot5: without dividing by the DC the ratio between the standard deviations changes a little bit.
 
 
I placed the detection unit at an intermediate distance: 25mm further than the original position.
 
Plot6:Comparison of small and tamasize sample. The small sample makes more noise the tamasize mirror.
 
I restored the original position of the detection unit and placed the chopper on a chair. So the chopper vibrations are not propagating on the optical table.
Plot7: It looks like the chopper vibrations contributes for 25% on the total noise.
 
I used the internal oscillator of the lockin amp to avoid any phase noise due to the chopper frequency instability.
Plot8: Tamasize sample. The phase noise doesn't look to have significant  contribution.
Plot9: Comparison of Tamasize and small sample. The reference signal is the lockin internal oscillator. Situation is same as with the chopper reference.
 
Result. Most of the noise doesn't come from the chopper vibration.  I still don't understand where it comes from.
 
 
 
Images attached to this report
252_20160612123720_plot1.png 252_20160612123729_plot2.png 252_20160612123740_plot3.png 252_20160612123749_plot4.png 252_20160612123755_plot5.png 252_20160612123804_plot6.png 252_20160612123825_plot7.png 252_20160612123833_plot8.png 252_20160612123839_plot9.png