| ID |
Date |
Author |
Type |
Category |
Subject |
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10207
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Tue Jul 15 22:23:51 2014 |
Andres | Update | 40m Xend Table upgrade | Scan the Xarm for the mode matching |
Nick and I with the help of Jenne scan the green light when the cavity is unlocked. Nick placed a Beam dump on the IR so that we can just scan the green, but it was removed as soon as we finished with the measurement. I'm working on the calculation, and i'll be posted solution tonight. |
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10226
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Thu Jul 17 02:57:32 2014 |
Andres | Update | 40m Xend Table upgrade | FInish Calculation on Current X-arm mode Matching |
Data and Calculation for the Xarm Current Mode Matching
Two days ago, Nick, Jenne, and I took a measurement for the Green Transmission for the X-arm. I took the data and I analyzed it. The first figure attached below is the raw data plotted. I used the function findpeaks in Matlab, and I found all the peaks. Then, by taking close look at the plot, I chose two peaks as shown in the second figure attached below. I took the ratio of the TEM00 and the High order mode, and I average them. This gave me a Mode Matching of 0.9215, which this value is pretty close to the value that I predicted by using a la Mode in http://nodus.ligo.caltech.edu:8080/40m/10191, which is 0.9343. Nick and I measured the reflected power when the cavity is unlocked and when the cavity is locked, so we measured the PreflUnLocked=52+1µW and PreflOnLocked=16+2µW and the backgroundNoise=0.761µW. Using this information we calculated Prefl/Pin=0.297. Now, since Prefl/Pin=|Eref/Ein|2, we looked at the electric fields component by using the reflectivity of the mirror we calculated 0.67. The number doesn't agree, but this is because we didn't take into account the losses when making this calculation. I'm working in the calculation that will include the losses.
Today, Nick and I ordered the lenses and the mirrors. I'm working in putting together a representation of how much improvement the new design will give us in comparison to the current setup.
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| Attachment 1: RawDataForTheModeGreenScan.png
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| Attachment 2: ResultForModeMatching.png
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| Attachment 3: DataAndCalculationOfModeMismatch.zip
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10237
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Fri Jul 18 16:52:56 2014 |
Andres | Update | 40m Xend Table upgrade | FInish Calculation on Current X-arm mode Matching |
| Quote: |
|
Data and Calculation for the Xarm Current Mode Matching
Two days ago, Nick, Jenne, and I took a measurement for the Green Transmission for the X-arm. I took the data and I analyzed it. The first figure attached below is the raw data plotted. I used the function findpeaks in Matlab, and I found all the peaks. Then, by taking close look at the plot, I chose two peaks as shown in the second figure attached below. I took the ratio of the TEM00 and the High order mode, and I average them. This gave me a Mode Matching of 0.9215, which this value is pretty close to the value that I predicted by using a la Mode in http://nodus.ligo.caltech.edu:8080/40m/10191, which is 0.9343. Nick and I measured the reflected power when the cavity is unlocked and when the cavity is locked, so we measured the PreflUnLocked=52+1µW and PreflOnLocked=16+2µW and the backgroundNoise=0.761µW. Using this information we calculated Prefl/Pin=0.297. Now, since Prefl/Pin=|Eref/Ein|2, we looked at the electric fields component by using the reflectivity of the mirror we calculated 0.67. The number doesn't agree, but this is because we didn't take into account the losses when making this calculation. I'm working in the calculation that will include the losses.
Today, Nick and I ordered the lenses and the mirrors. I'm working in putting together a representation of how much improvement the new design will give us in comparison to the current setup.
|
We want to be able to graphically see how much better it is the new optical table setup in comparison to the current optical table setup. In other words, we want to be able to see how displacement of the beam and how much angle change can be obtained at the ETM from changing the mirrors angles independently. Depending on the spread of the mirrors' vectors we can observe whether the Gouy phase is good. In the plot below, the dotted lines correspond to the current set up, and we can see that the lines are not spread from each other, which essentially mean that changing the angles of the two mirrors just contribute to small change in angle and in the displacement of the beam at the ETM, and therefore the Gouy phase is not good. Now on the other hand. The other solid lines correspond to the new setup mirrors. We can observe that the spread of the line of mirror 1 and mirror 4 is almost 90 degrees, which just implies that there is a good Gouy phase different between these two mirrors. For the angles chosen in the plot, I looked at how much the PZT yaw the mirrors from the elog http://nodus.ligo.caltech.edu:8080/40m/8912. In this elog, they give a plot in mrad/v for the pitch and yaw, so I took the range that the PZT can yaw the mirrors, and I converted into mdegrees/v and then I plotted as shown below. I plot for the current setup and for the new setup in the same plot. The matlab code is also attached below. |
| Attachment 1: OldAndNewSetupPlotsOfDisplacementAndAngleAtTheETM.png
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| Attachment 2: OldSetUpDisplacementAndNewSetup.m.zip
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10290
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Tue Jul 29 20:14:08 2014 |
Andres | Update | 40m Xend Table upgrade | Xarm Green steering mirror upgrade |
Xarm Green Steering Mirror Upgrade
Nick and I did the upgrade for the green steering mirror today. We locked in the TEM00 mode.
We placed the shutter and everything. We move the OL, but we placed it back. Tonight, I'll be doing a more complete elog with more details. |
|
10296
|
Wed Jul 30 10:16:54 2014 |
Andres | Update | 40m Xend Table upgrade | Green Steering Mirror Upgrade completed |
Green Steering Mirror Update
Yesterday, Nick and I completed the green steering mirrors upgrade. I attached the file that contained the procedure that we plan before we did the upgrade. We placed an iris at the input of the OL and we place another iris before the harmonic separator. We did not use the beam scanner because someone was using it, so what we did was to assume that the cavity is well align and place the iris so that we can recover the alignment. We used the measuring tape to approximate as close as we could the position where the lenses were supposed to go. I did a measurement of the derivative of the waist size in terms of the position of the lens and the derivative of the waist Position in terms of the lenses position at the optimum solution that a la mode give us. Because of this plot, we decide to mount lens 3 and lens 5 into translational stages. After mounting each lenses and mirrors we worked on the alignment of the beam into the cavity. We were able to align the green into the cavity and we were able to locked the cavity to the TEM00 mode. We started to work on the optimization of the mode matching. However, the maximum mode matching that we got was around 0.6, which we need to work a little bit more on the tuning of the mode matching. We leave the iris mounted on the table. I took a picture of the table, and I attached below. For the OL, we just make sure that the output where somehow hitting the QPD, but we didn't really I aligned it. We need to work a little bit more on the alignment of the OL and the tuning of the mirror to maximize the green mode matching. |
| Attachment 1: XarmUpgrade.pdf
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| Attachment 2: dWaistSize_dlensVsdWaistPosition_dlens.png
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| Attachment 3: XarmNewOpticalSetup.PNG
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10374
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Wed Aug 13 10:50:04 2014 |
Andres | Update | IMC | Calculation for the input mode cleaner |
Calculation for the input mode cleaner
I have been working on the calculation for the input mode cleaner. I have come out with a new optical setup that will allow us increase the Gouy phase different between the WFS to 90 degrees. I use a la mode to calculate it. The a la mode solution :
label z (m) type parameters
----- ----- ---- ----------
MC1 0 flat mirror none:
MC3 0.1753 flat mirror none:
MC2 13.4587 curved mirror ROC: 17.8700
Lens1 29.6300 lens focalLength: 1.7183
BS2 29.9475 flat mirror none:
First Mirror 30.0237 flat mirror none:
WFS1 30.2269 flat mirror none:
Second Mirror 30.2650 flat mirror none:
Third Mirror 30.5698 flat mirror none:
Lens2 30.9885 lens focalLength: 1
Fourth Mirror 31.0778 flat mirror none:
Lens3 31.4604 lens focalLength: 0.1000
Fifth Mirror 31.5350 flat mirror none:
Sixth Mirror 31.9414 flat mirror none:
WFS2 31.9922 flat mirror none:
I attached a pictures how the new setup is supposed to look like. |
| Attachment 1: ModeCleanerSetup0.PNG
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| Attachment 2: alaModeModeCleanersolution.png
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10384
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Thu Aug 14 15:10:47 2014 |
Andres | Update | IMC | Calculation for the input mode cleaner |
| Quote: |
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Can you please give us some more details on how this design was decided upon? What were the design considerations?
It would be nice to have a shorter path length for WFS2. What is the desired spot size on the WFS? How sensitive are they going to be to IMC input alignment? Are we still going to be recentering the WFS all the time?
|
I did the calculation, and I reduced the beam Path. In my calculation, I restricted the waist size at the WFSs to be between 1mm-2mm also the other parameter is that the Gouy Phase different between the WFSs have to be 90 degrees. I also try to minimize the amount of mirrors used. I found the Gouy phase to be 89.0622 degrees between the WFSs and the following table shows the solution that I got from a la mode:
label z (m) type parameters
----- ----- ---- ----------
MC1 0 flat mirror none:
MC3 0.1753 flat mirror none:
MC2 13.4587 curved mirror ROC: 17.8700 (m)
Lens1 28.8172 lens focalLength: 1.7183(m)
BS2 29.9475 flat mirror none:
First Mirror 30.0237 flat mirror none:
Lens3 30.1253 lens focalLength: -0.100 (m)
Lens2 30.1635 lens focalLength: 0.1250(m)
WFS1 30.2269 flat mirror none:
Second Mirror 30.2650 flat mirror none:
Third Mirror 30.5698 flat mirror none:
Lens4 30.8113 lens focalLength: -0.075 (m)
WFS2 31.0778 flat mirror none:
In the first image attached below is the a la mode solution that show the waist size in the first WFS, and I used that solution to calculate the solution of the waist size for the second WFS, which is shown in figure 2. I photoshop a picture to illustrate how the new setup it supposed to look like. |
| Attachment 1: SolutionForTheModeCleanerSetup00.png
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| Attachment 2: SolutionForTheModeCleanerSetup11.png
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| Attachment 3: PossibleSetupForModeCleaner.PNG
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| Attachment 4: alaModeSolution.zip
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10410
|
Tue Aug 19 21:40:44 2014 |
Andres | Update | IMC | New Optical Setup for the IMC |
IMC Calculation and Setup
I have been working in the calculation for improving the Gouy Phase separation between the WFSs. I tried different possible setup, but the three big constrains in choosing a good optical table setup are to have a Waist size that range from 1mm-2mm, the Gouy Phase between the WFSs have to be greater than 75 degrees and there has to be a steering mirror before each WFS. I will be showing the best calculation because that calculation complies with Rana request of having both WFSs facing west and having the shortest beam path. I approximate the distances by measuring with a tape the distance where the current optics are located and by looking at the picture that I took I approximated the distance where the lenses will be placed. I'm using a la mode for calculating the gouy phase different. I attached a picture of the current optical table setup that we have. Using a la mode, I found that the current gouy phase that we have is 49.6750 degrees.
Now, for the new setup, a run a la mode and found a Gouy phase of 89.3728 degrees. I have to create a two independent beam path: one for the WFS1 and another one for WFS2. The reason for this is that a la mode place everything in one dimension so and since the WFS1 will have a divergence lens in order to increase the waist size, and since that lens should not be interacting with the waist size in the WFS2. We need two beam path for each WFS. A la mode give us the following solution:
For the beam path of the WFS1
label z (m) type parameters
----- ----- ---- ----------
MC1 0 flat mirror none:
MC3 0.1753 flat mirror none:
MC2 13.4587 curved mirror ROC: 17.8700 (m)
Lens1 29.3705 lens focalLength: 1.0201 (m)
BS2 29.9475 flat mirror none:
First Mirror 30.0237 flat mirror none:
Lens3 30.2000 lens focalLength: -0.100 (m)
WFS1 30.4809 flat mirror none:
For the beam path of the WFS2
label z (m) type parameters
----- ----- ---- ----------
MC1 0 flat mirror none:
MC3 0.1753 flat mirror none:
MC2 13.4587 curved mirror ROC: 17.8700 (m)
Lens1 29.3705 lens focalLength: 1.0201 (m)
BS2 29.9475 flat mirror none:
Second Mirror 30.2650 flat mirror none:
Lens2 30.4809 lens focalLength: -0.075 (m)
Third Mirror 30.5698 flat mirror none:
WFS2 30.6968 flat mirror none:
I attached bellow how the new setup should look like in the second picture and also I include and attachment of the a la mode code.
I used Mist to be able to see the read out that we get in the WFSs that take the Mode Cleaner Reflection and the QPD that take the transmitted from MC2. In the following, plots I'm misaligned the each mirrors: MC1, MC2 and MC3. The misalignment are in Yaw and Pitch. I'm dividing the WFSs reading by the total power reflect power, and I'm dividing the QPD for the MC2 transmission by the total transmitted power. In my Mist model, I have a laser of 1W and my EOM is modulated at 30MHz instead of 29.5MHz and the modulation depth was calculating by measuring the applied voltage using and Spectrum analyzer. I using Kiwamu measurement of modulation depth efficiency vs the applied voltage, https://dcc.ligo.org/DocDB/0010/G1000297/001/G1000297-v1.pdf, I got a modulation depth of 0.6 mrad. I put this modulation depth and I got the following plots: The fourth and fifth attachment are for the current optical setup that we have. The sixth and seventh attachment is for the new optical setup. The eighth attachment is showing the mode cleaner cavity resonating. The last attachment contains the plots of WFS1 vs WFS2, MC2_QPD vs WFS1, MC2_QPD vs WFS3 for each mirror misaligned. The last two attachment are the MIST code for the calculation.
We have all the lenses that we need. I checked it last Friday and if everything is good we will be ready to do the new upgrade this coming Friday. For increasing the power, I check and we have different BS so we can just switch from the current setup the BS. Can you let me know if this setup look good or if I need to chance the setup? I would really love to do this upgrade before I leave.
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| Attachment 1: ModeCleanerSetup.PNG
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| Attachment 2: NewOpticalTableSetupForTheModeCleaner.PNG
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| Attachment 3: ReduceWFSPathWorkingOn.m.zip
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| Attachment 4: MIST_WFSsAndQPDReadingForYaw.png
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| Attachment 5: MIST_WFSsAndQPDReadingForPitch.png
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| Attachment 6: MIST_WFSsAndQPDReadingForYawNewSetup.png
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| Attachment 7: MIST_WFSsAndQPDReadingForPitchNewSetup.png
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| Attachment 8: MISTResonanceCavityReflectionAndTransmissionNewSetup.png
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| Attachment 9: 2Dplots.zip
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| Attachment 10: ModeCleanerCurrentOpticalTableMIST.zip
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| Attachment 11: ModeCleanerNewSetupMIST.zip
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10427
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Fri Aug 22 18:05:02 2014 |
Andres | Update | IMC | Upgrade of the IMC WFSs for the reflection |
Upgrade of IMC Reflection Optical Setup
Nick and I upgrade the IMC. We move both WFSs and placed them facing west. When aligning the beam into the WFS, we make sure that the beam were hitting the center of the mirrors and then we placed the lenses in their corresponding position. We used the beam scanner to measure the waist and the waist in the second WFS was bigger than 1mm, and the second WFS was a little bit below than 1mm. We center the beam in the WFSs and in the PD. We did haven't measure whether we have a good Gouy Phase. Below I attached the picture of how the new setup look like.
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| Attachment 1: ModeCleanerUpgrade.PNG
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10101
|
Wed Jun 25 14:52:22 2014 |
Andres Medina | Update | elog | Placing a lens between the steering mirrors and another lens between the second steering mirror and the cavity |
I was asked to calculate the lenses that we need in order to obtained a Gouy phase close to 90 degrees between the two mirrors that are in the Xend green. Yesterday, I measured the distances between the mirrors, and the distance between the mirror relative to the cavity as illustrate in the image attached below. I looked in to the 40m elog and Manasa did the last update on the length of the cavity. She measured 37.7 + 0.05m. The waist size of the beam that was measured by Annalisa in ID 8637 after the Faraday was w0=2.943e-5m @ -0.039m. I calculated the waist size inside the cavity, and I found a waist of w0=2.2 mm. My plan this week is to keep working in the calculation and finish all the calculation this week so that next week I can go inside and place the lenses. |
| Attachment 1: SchematicForXendGreenGoingToTheCavity.pdf
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75
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Wed Nov 7 02:14:08 2007 |
Andrey | Bureaucracy | IOO | More information about MC2 ringdown |
As Tobin wrote two hours ago, we (Andrey, Tobin, Robert) made a series of ringdown measurements for MC2
in the spirit of the measurement described by Rana -> see
entry from Mon Oct 29 23:47:29 2007, rana, Other, IOO, MC Ringdowns.
I attach here some pictures that we saw on the screen of the scope, but I need to admit that I am not experienced enough to present a nice fit to these data, although I attach fits that I am able to do today.
I definitely learned a lot of new Matlab functions from Tobin - thanks to him!, but I need to learn two more things:
Firstly, I do not know how to delete "flat" region (regions before the ringdown starts) in Matlab ->
I needed to delete the entries for times before the ringdown ("negative times") by hand in the text-file, which is extremely non-elegant method;
Secondly, I tried to approximate the ringdown curve by a function ydata=a*exp(b*xdata) but I am not exactly sure if this equation of the fitting curve is a good fit or if a better equation can be used.
It seems, in this situation it is better for me to ask more experienced "comrades" on November 7th.
P.S. It seems I really like the type of message "Bureaucracy" - I put it for every message. As Alain noted, maybe that is because some things are very bureacratized in the former USSR / Russia. By the way, when I was young, November 7th was one of two most important holidays in the USSR - I liked that holiday because I really liked military parades on the red square. I attach a couple of pictures. November 7 is the anniversary of the Revolution of 1917. |
| Attachment 1: image-attempt_1.png
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| Attachment 2: image-attempt_2.png
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| Attachment 3: image-attempt_3.png
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| Attachment 4: image-attempt_4.png
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| Attachment 5: image-attempt_5.png
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| Attachment 6: Fit-1st_attempt.jpg
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| Attachment 7: Fit-5th_attempt.jpg
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| Attachment 8: 7_Nov_1941-parad-na-krasnoy-ploschadi.jpg
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| Attachment 9: parad1984-moskva.jpg
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130
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Wed Nov 28 12:43:53 2007 |
Andrey | Bureaucracy | | Here was the PDF-file of my presentation |
I was making a report with powerpoint presentation during that Wednesday's 40-m meeting.
Here was the pdf-file, but LATER IN THE EVENING I CREATED A WIKI-40M-page describing the algorithm, and now the pdf-file is ON THAT WIKI-40M PAGE.
NOTE ADDED AFTER THE PRESENTATION: I double checked, I am indeed taking the root-mean-square of a difference, as we discussed during my talk.
My slide #17 "Calculation of differential length" was wrong, but now I corrected it. |
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135
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Wed Nov 28 19:02:41 2007 |
Andrey | Bureaucracy | WIKI-40M Update | New WIKI-40M page describing Matlab Suspension Modeling |
I created the WIKI-40m page with some details about my today's talk on the 40-m lab meeting.
The address is:
http://lhocds.ligo-wa.caltech.edu:8000/40m/Modeling_of_suspensions
(or you can go to the main page, http://lhocds.ligo-wa.caltech.edu:8000/40m/ , and click on the link "Modeling of suspensions").
The WIKI-40m page describes my transfer functions and contains the pdf-file of my presentation. |
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151
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Fri Nov 30 20:17:26 2007 |
Andrey | Configuration | PEM | Accelerometers and alum.plates for them |
All 6 accelerometers which were located near the ITMX are turned off and disconnected from the power cords.
Actually these accelerometers are now in the office area on the electronics bench (to the left from Steve Vass' place).
I made today 4 new aluminum mounting plates for the accelerometers (I drilled holes and made threads in them). On Monday I will buy short screws and install accelerometers on these new mounting plates. These mounting plates will be screwed directly into the metallic frame which is firmly cemented to the ground. Before yesterday accelerometers were mounted on top of blue stack towers, not on the ground directly, so we hope that new measurements of the ground noise will be more realistic.
The 4 mounting plates are on the same desk -> on the electronics bench (to the left from Steve Vass' place). Please do not displace them.
Attached is a drawing of the aluminum mountain plate. |
| Attachment 1: Scheme_Aluminum_Piece-inches.pdf
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168
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Wed Dec 5 18:08:36 2007 |
Andrey | Update | ASC | Optical Lever laser for ETMX is installed |
A new laser with \lambda=633nm has been intalled and the mirror adjusted so that the signal hits the center of the photodetector.
Output power level of that laser is 3.45 +- 0.05 mW.
Only about 0.29mW hits the photodetector.
Cable clips have been used to firmly fix the power supply cable for the laser.
See attached photopicture of the ETMX - "oplev" - optical - table. |
| Attachment 1: DSC_0199.JPG
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172
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Wed Dec 5 23:19:03 2007 |
Andrey | Configuration | PEM | Accelerometers are turned on |
All accelerometers have been turned on, as Alan asked during Wednesday meeting.
Typical power spectra and coherence plots are attached below.
"East" in the name means that the previous location of accelerometrs was to the east from "Beamsplitter" (the location for "east" accelerometers was not changed, actually, it is still near ITMX), while "west" means that previously accelerometers were to the west from the BS, but now their new location is near the ETMX.
I will change the names of the channels tomorrow (Thursday) when someone (Tobin?) will show to me how to do it.
P.S. (addition made on Dec. 19th, 2007, by Andrey) I intended to change the names of accelerometers the next day, Thursday Dec. 06,
but I did not do it that day (did not understand how to do it), then I fell ill, and eventually
I changed the names of accelerometers on December 19th, see entry to ELOG #204) |
| Attachment 1: Power_Sp_and_Coh_XY-EAST.pdf
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| Attachment 2: Coherence-ZX_East.pdf
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| Attachment 3: Coherence-ZY_East.pdf
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| Attachment 4: Power_Sp_WEST.pdf
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| Attachment 5: Coherence-ZX_West.pdf
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| Attachment 6: Coherence-XY_West.pdf
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| Attachment 7: Coherence-YZ_West.pdf
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174
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Thu Dec 6 15:22:42 2007 |
Andrey | Summary | Electronics | Pictures of the inside of He-Ne laser |
Steve gave me an old "dead" He-Ne laser that long time ago was used for ETMX optical lever.
I dismantled it (cutting the metallic enclosure with a metallic saw), and these are two pictures of what is inside. |
| Attachment 1: DSC_0226.JPG
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| Attachment 2: DSC_0228.JPG
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176
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Thu Dec 6 19:19:47 2007 |
Andrey | Configuration | SUS | Suspension damping Gain was restored |
Suspension damping gain was disabled for some reason (all the indicators in the most right part of the screen C1SUS_ETMX.adl were red), it is now restored. |
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191
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Thu Dec 13 23:56:02 2007 |
Andrey | Configuration | Computer Scripts / Programs | Overnight measurements |
After my disease (fever, vomitting, nose problem, overall weakness) I returned to LIGO today for the first time after the weekend, and I am running the script for the XARM-measurements over this night.
So, suspension dumping gains should undergo changes in the interval from 1 to 10 in both ITMX and ETMX.
XARM has been of course locked.
I started running the script for the first time at about 10PM, but I realized after an hour and a half that my step of gain increase 0.2 was too shallow, too small to execute my program during one night. Therefore, I needed to terminate the program, change my program so that it increases the gain with increment 0.5, not 0.2, and started it again around midnight.
Going home.
P.S. The red pump that I borrowed from the lab (Steve's pump?) is back at its previous place. The tire-worker tells me that I absolutely need to change all four tires for almost 500 dollars. I regret a lot about that huge money loss. |
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194
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Mon Dec 17 23:42:08 2007 |
Andrey | Configuration | Computer Scripts / Programs | Overnight measurements in X-arm |
I am making overnight measurements this night (from Monday to Tuesday) in XARM.
The X-arm is now locked, and the values for suspension damping gain will be changed in the interval from 1 to 7 with the step 0.5 in both ITMX and ETMX.
This is the second, repeated measurement. The results of the first measurement from Saturday to Sunday night will be reported in the separate ELOG entry (sorry, I did not make an ELOG entry on Saturday evening about running the program overnight).
The very first attempt to run the script in the night from Thursday to Friday was not successful. |
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195
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Tue Dec 18 00:51:39 2007 |
Andrey | Update | Computer Scripts / Programs | Results of Saturday overnight measurements |
As I indicated in the previous e-log entry (#194), I made overnight measurements in XARM in the night from Saturday to Sunday.
Root-mean-square values of the peaks in calibrated spectra were calculated, and I plotted them as functions of suspension gains in ITMX and ETMX "position" degrees of freedom.
More specifically, Q_ITMX means the value in the channel "C1:SUS-ITMX_SUSPOS_GAIN", while Q_ETMX means the value in the channel "C1:SUS-ETMX_SUSPOS_GAIN".
Root-mean-square values (RMS) were calculated during that night in three intervals:
1) around 0.8 HZ in the interval (0.6 Hz <-> 1.0 Hz);
2) around 3.0 Hz in the interval (2.0 Hz <-> 3.6 Hz);
3) in the broad interval from 0.6Hz to 3.6Hz.
I plotted three results for RMS in the abovementioned three intervals in three different ways:
1) view from the top in the axes (Q_{ITMX}+Q_{ETMX})/2 and (Q_{ITMX}-Q_{ETMX}) -> first three graphs (attachments 1 -3);
2) view from the side in the same sum- and difference-axes -> next three graphs (attachments 4-6);
3) view from the side in Q_{ITMX} and Q_{ETMX} axes -> next three graphs (attachments 7-9), above accelerometer spectra (attachments 10-11).
Also, I compared the ground noise level by comparing spectra of accelerometer signals at different times during that night. As a reminder, before my disease I installed one accelerometer near ITMX and another accelerometer near ETMX (see entries 161 and 172 in ELOG). The plots of ratios of accelerometer signals at different times (pairs of times that were used: 12AM and 3AM, 12AM and 6AM, 12AM and 9AM) are given below, see attachments 10-11.
Tomorrow I will try to compare the results with the second measurements that are being taken tonight. |
| Attachment 1: RMS_08Hz_top_view.png
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| Attachment 2: RMS_3Hz_top_view.png
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| Attachment 3: RMS_broad_top_view.png
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| Attachment 4: RMS_08Hz_Qsum-Qdiff-axes.png
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| Attachment 5: RMS_3Hz_Qsum-Qdiff-axes.png
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| Attachment 6: RMS_broad_Qsum-Qdiff-axes.png
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| Attachment 7: RMS_08Hz_Qaxes.png
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| Attachment 8: RMS_3Hz_Qaxes.png
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| Attachment 9: RMS_broad_Qaxes.png
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| Attachment 10: Accel_ITMX.png
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| Attachment 11: Accel_ETMX.png
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198
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Tue Dec 18 23:27:36 2007 |
Andrey | Configuration | Computer Scripts / Programs | New overnight measurements (this night from Tue to Wed) |
I am making overnight measurements in XARM tonight.
This is the third night of measurements in XARM, but tonight I am scanning the narrower region between values of damping gain 1.00 and 4.50 with the smaller step 0.25. (for comparison, during two previous measurements the region was between 1.0 and 7.0 with the step 0.5).
I have relocked the XARM before the start of the measurements.
I started running the program at 9.30PM, and it should collect all the data by 9.00AM wednesday morning.
Below are explanations why I chose these different parameters for the interval and step:
I am going to put the results of previous night measurements into the next ELOG entry, and it we be pretty obvious from those graphs that results in XARM from the two previous (different) nights agree well with each other, and the approximate positions of minima and areas of "big growth" of the surfaces are pretty obvious from those graphs. It is clear that RMS are too big for the values of the damping gain bigger than 4.0, and that minima are somewhere near the values of 2.0. But those graphs were too rough to locate a somewhat precise value for the minima. Therefore, I am studying tonight the interval of gains between 1.00 and 4.50 with a smaller step.
A short note how I estimate time that is necessary to collect the experimental data.
there are 15 experimental points for each ETMX and ITMX suspension gains in the interval between 1.00 and 4.50 with the step 0.25. They are: 1.00, 1.25, 1.50, 1.75, 2.00, ..., 3.75, 4.00, 4.25, 4.50. As I am changing both ETMX and ITMX gains, I have an array of 15*15=225 elements.
It takes 3 minutes for each point to collect the data (I wrote the program that way). Therefore, the total time it takes to run the program is: 225*3=675 minutes, or 675/60=11.25 hours, almost 11 and a half hours. |
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Tue Dec 18 23:41:00 2007 |
Andrey | Summary | Computer Scripts / Programs | Results of Mon/Tue overnight measurements (entry #194) |
Here I inform our community about the results of the measurements of RMS values in XARM during the previous night from Monday to Tuesday (I announced those measurements in ELOG entry #194).
All the plots in today's report seem to agree well with the analogous plots from the night from Saturday to Sunday (those results are given in ELOG entry # 195).
All the intervals in which RMS have been calculated are the same as in yesterday's ELOG entry #195.
I plotted three results for RMS in the abovementioned three intervals in three different ways:
1) view from the top in the axes (Q_{ITMX}+Q_{ETMX})/2 and (Q_{ITMX}-Q_{ETMX}) -> first three graphs (attachments 1 -3);
2) view from the side in the same sum- and difference-axes -> next three graphs (attachments 4-6);
3) view from the side in Q_{ITMX} and Q_{ETMX} axes -> next three graphs (attachments 7-9, also attch. 12), above accelerometer spectra (attachments 10-11).
Also, I compared the ground noise level by comparing spectra of accelerometer signals at different times during that night. As a reminder, before my disease I installed one accelerometer near ITMX and another accelerometer near ETMX (see entries 161 and 172 in ELOG). The plots of ratios of accelerometer signals at different times (pairs of times that were used: 11PM and 2AM, 11PM and 5AM, 11PM and 8AM) are given below, see attachments 10-11. The program was running from 11PM on Monday till 9AM on Tuesday.
As I explained in the previous ELOG entry # 198, tonight I am taking experimental data in the narrowere interval from 1.00 to 4.50 with a smaller step 0.25. |
| Attachment 1: RMS_08HZ_Top_View.png
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| Attachment 2: RMS_3HZ_Top_View.png
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| Attachment 3: RMS_broad_Top_View.png
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| Attachment 4: RMS_08HZ_Side_View.png
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| Attachment 5: RMS_3HZ_Side_View.png
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| Attachment 6: RMS_broad_Side_View.png
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| Attachment 7: RMS_08HZ_Q_E_Q_I_Axes.png
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| Attachment 8: RMS_3HZ_Q_E_Q_I_Axes.png
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| Attachment 9: RMS_broad_Q_E_Q_I_Axes.png
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| Attachment 10: Accelerometer_ITMX.png
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| Attachment 11: Accelerometer_ETMX.png
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| Attachment 12: RMS_broad_Q_E_Q_I_Axes.png
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Wed Dec 19 15:51:00 2007 |
Andrey | Update | Computer Scripts / Programs | Daytime measurements in XARM and their results |
I was making measurements in XARM for three different nights. All the results agree with each other (I will put the results from the last night soon).
Steve Vass recommended to me to compare those results with the daytime data, in order to see if there is a real necessity to run the scripts overnight or if daytime results will yield similar results.
XARM has been locked, and I am taking measurements today from 3.30PM till 11.30PM.
I will be changing the suspension damping gains in ETMX and ITMX "position" degrees of freedom in the interval from 1.0 to 3.75 with the step 0.25.
BELOW: RESULTS OF MEASUREMENTS WERE ADDED ON THURSDAY, DEC. 20.
All the meaning of the attachments 1-3, 4-6, 7-9, 10-11 is the same as in previous ELOG entries # 195, # 199, # 202, see in those entries which graph corresponds to which coordinate axes orientation. |
| Attachment 1: RMS-08Hz-Top_View.png
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| Attachment 2: RMS-3Hz-Top_View.png
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| Attachment 3: RMS-broadband-Top_View.png
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| Attachment 4: RMS-08Hz-Side-View.png
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| Attachment 5: RMS-3Hz-Side_View.png
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| Attachment 6: RMS-broadband-Side_View.png
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| Attachment 7: RMS-08Hz-Q_I-Q_E-Axes.png
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| Attachment 8: RMS-3Hz-Side_View.png
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| Attachment 9: RMS-broadband-Side_View.png
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| Attachment 10: Accelerometer_ETMX.png
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| Attachment 11: Accelerometer_ITMX.png
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Wed Dec 19 16:07:37 2007 |
Andrey | Summary | Computer Scripts / Programs | Results of overnight measurements Tue/Wed night (entry #198) |
As indicated in ELOG entry 198, I was making overnight measurements during last night from Tuesday to Wednesday.
I was changing the suspension damping gain in ETMX and ITMX in "position" degree of freedom between values of 1.00 and 4.50 with the step 0.25.
Results for RMS of peaks (A) at 0.8Hz, (B) at about 3.0Hz and (C) in the range from 0.6Hz to 3.7Hz ("RMS in a broad interval") are given below:
I plotted three results for RMS in the abovementioned three intervals in three different ways:
1) view from the top in the axes (Q_{ITMX}+Q_{ETMX})/2 and (Q_{ITMX}-Q_{ETMX}) -> first three graphs (attachments 1 -3);
2) view from the side in the same sum- and difference-axes -> next three graphs (attachments 4-6);
3) view from the side in Q_{ITMX} and Q_{ETMX} axes -> next three graphs (attachments 7-9)
Attachments 10 and 11 show ratios of accelerometer signals at different times of the night/morning.
A little discussion about these graphs:
1) The areas of minima and of rapid growth are the same for all the measurements during all three nights.
2) Tonight there was a strange spike for the values of Q_{ETMX}=2.5 and Q_{ITMX}=4.0. I interpret that as an error of experiment.
3) On all the plots from all three nights there is a wide area of minimum on the plots for RMS at 0.8Hz and for "RMS in the broad interval",
and the graph for "RMS at 3Hz" indicates a clearer minimum in a localized area for Q_{ITMX}=2+-1, Q_{ETMX}=2+-1. Note that this area 2+-1
is included into the wide region of minimum for "RMS at 0.8Hz" and "RMS in a broad range".
Therefore, my guess at this stage is that we can choose the optimized value of suspension damping gains for both Q_{ITMX} and Q_{ETMX} somewhere
around 2+-1. I would like to make another overnight measurement (tonight) in that narrowed region with a small step to have more certainty.
By the way, I realized that I was a little bit careless and at some plots Q_I stands for {Q_ITMX}, and Q_E stands for Q_{ETMX}.
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| Attachment 1: RMS_08Hz_Top_view.png
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| Attachment 2: RMS_3Hz_Top_view.png
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| Attachment 3: RMS_broad_Top_view.png
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| Attachment 4: RMS_08Hz_Side_view.png
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| Attachment 5: RMS_3Hz_Side_view.png
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| Attachment 6: RMS_broadband_Side_view.png
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| Attachment 7: RMS_08Hz_Q_I-Q_E-axes.png
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| Attachment 8: RMS_3Hz_Q_I-Q_E-axes.png
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| Attachment 9: RMS_broadband_Q_I-Q_E-axes.png
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| Attachment 10: Accelerom_ETMX.png
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| Attachment 11: Accelerom_ITMX.png
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Wed Dec 19 20:28:27 2007 |
Andrey | DAQ | PEM | Names for all 6 accelerometers have been changed |
I eventually changed the names for all 6 accelerometers (see my ELOG entry # 172 from Dec. 05 about my intent to do that).
I removed the word "BS" from their names,
and I changed the word combination "ACC_BS_EAST" in the old name for "ACC_ITMX" in the new name;
as well "ACC_BS_WEST" is now replaced by "ACC_ETMX".
(the reasoning behind such a change should become clear from my ELOG entry #172).
New accelerometer names are:
(note: there are no spaces (nowhere!) in the names of accelerometers, but ELOG replaces ": P" written without a space by a strange symbol  )
C1 : PEM - ACC _ ETMX _ X ;
C1 : PEM - ACC _ ETMX _ Y ;
C1 : PEM - ACC _ ETMX _ Z ;
C1 : PEM - ACC _ ITMX _ X ;
C1 : PEM - ACC _ ITMX _ Y ;
C1 : PEM - ACC _ ITMX _ Z .
One can find them in "C1 : PEM - ACC" in Dataviewer.
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Thu Dec 20 02:04:09 2007 |
Andrey | Update | Computer Scripts / Programs | New overnight measurements in XARM and their results |
I ran in the daytime/evening time my program, changing the damping gains in suspension "position" degree of freedom for ETMX and ITMX
in the interval from 1.00 to 3.75 with the step 0.25 (see entry # 201).
Now I am running overnight (from 2AM till 9AM) the program changing the gains in the interval from 1.3 to 3.5 with the step 0.20,
12 X 12 = 144 experimental points. I started so late because I fell asleep after my Wednesday evening dinner, then woke up half an hour ago and hurried to the lab.
BELOW: RESULTS OF MEASUREMENTS WERE ADDED ON THURSDAY EVENING, DEC. 20.
All the meaning of the attachments 1-3, 4-6, 7-9, 10-11 is the same as in previous ELOG entries # 195, # 199, # 202, see in those entries which graph corresponds to which coordinate axes orientation. |
| Attachment 1: RMS-08Hz-Top-View.png
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| Attachment 2: RMS-3Hz-Top-View.png
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| Attachment 3: RMS-broadband-Top-View.png
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| Attachment 4: RMS-08Hz-Side_View.png
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| Attachment 5: RMS-3Hz-Side_View.png
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| Attachment 6: RMS-broadband-Side_View.png
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| Attachment 7: RMS-08Hz-Q_I-Q_E-Axes.png
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| Attachment 8: RMS-3Hz-Q_I-Q_E-Axes.png
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| Attachment 9: RMS-broadband-Q_I-Q_E-Axes.png
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| Attachment 10: Accelerometer-ETMX.png
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| Attachment 11: Accelerometer-ITMX.png
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Thu Dec 20 21:57:34 2007 |
Andrey | Update | Computer Scripts / Programs | Measurements in XARM today |
Today at 2PM I started a program, it should change the suspension gains in the interval from 1.0 to 3.8 with the step 0.2. Estimated running time is till 3.30AM coming night.
Results will be reported on Friday.
BELOW: ADDITION MADE ON FRIDAY EVENING.
Due to some unforeseen circumstances, I was unable to add results on Friday. I have so far accelerometer spectra only, which I add to this ELOG entry.
I have files with the measurement results, and I will process them after Christmas and add to this ELOG entry. I might not be in the lab on Dec. 24 and 25. |
| Attachment 1: Accelerom_ETMX.png
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| Attachment 2: Accelerom_ITMX.png
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Thu Dec 20 21:58:28 2007 |
Andrey | Summary | Computer Scripts / Programs | Results for 2 previous XARM measurements have been added |
I attached results (plots) of yesterday's daytime and overnight measurements to the initial reports about those measurements.
These are ELOG entries # 201 and # 205. |
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Mon Jan 21 23:30:03 2008 |
Andrey | Update | Computer Scripts / Programs | Matlab Program for Q-factor measurements (XARM -> ITMX and ETMX) |
Finally I overcame difficulties with adapting Sonia's Matlab programs for XARM (Sonia's program was for MC),
and now there exists a Matlab program that makes a fit of a ringdown curve and calculates Q-factor for a mirror ITMX.
Specifically, this program allows to measure ringdown, fit it and calculate Q-factor for the ITMX-mirror for a specific value of
"C1:SUS-ITMX_SUSPOS_GAIN".
Attached is a plot of a ringdown curve and its fit for the value 4.0 in channel "C1:SUS-ITMX_SUSPOS_GAIN".
Calculations yield the result Q=3.7+-0.2 for the value 4.0 in channel "C1:SUS-ITMX_SUSPOS_GAIN".
As Robert started 10 minutes ago the long procedure of the whole interferometer locking,
I cannot disturb the interferometer now, so I will measure Q-factors for various combinations of suspension damping gain on Tuesday.
I will also easily modify the program for measuring Q-factors of ETMX-mirror and make measurements with ETMX on Tuesday.
The Matlab scripts are in directory /cvs/cds/caltech/users/rodionov/Q-Factors/ |
| Attachment 1: Example-ITMX_POS_40.png
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Wed Jan 23 12:31:36 2008 |
Andrey | Summary | SUS | Dissapointing Results of XARM optimization (PDF-file) |
I attach a PDF-file which summarizes briefly the results of measurements/calculations of Q-factors for ITMX mass as a function of suspension damping gain,
and this file contains the results of measurements of RMS peaks on the values of suspension gains of ITMX and ETMX (see ELOG entries from December 2007, specifically #202, #199, #194)),
but now those dependences are plotted in Q-ITMX and Q_ETMX axes.
Unfortunately, there are no clear narrow areas of minimum in those dependences (that explains the sad title of this ELOG entry).
The attached pdf-file can be shown as a short presentation for a wall during our Wednesday meeting. |
| Attachment 1: Sad_Results_XARM.pdf
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Thu Jan 24 20:03:40 2008 |
Andrey | Configuration | SUS | Changes to Dataviewer channels (XARM) |
1) Good news. I added a chanel "C1:SUS-ETMX_POS" to Dataviewer.
I followed the instructions from WIKI-40:
modify the file "C1SUS_EX.ini" in /cvs/cds/caltech/chans/daq,
then telnet to fb40m,
then "click the appropriate blue button on the DAQ MEDM screen".
So, I can now read a signal from the channel "C1:SUS-ETMX_POS" in Dataviewer,
and this allows me to measure Q-factors of ETMX this evening (make similar work for what I did on Tuesday for ITMX).
2) BAD NEWS. While "clicking the appropriate blue button" on the DAQ MEDM screen,
namely CODAQ_DETAIL,adl screen, I obviously clicked some blue button that I should not have clicked,
and as a result the signal in Dataviewer from the channel "C1:SUS-ITMX_POS" has disappeared (it is now a straight line).
Description of what has happened and of my wrong actions:
I had two channels opened in Dataviewer simultaneously (both "C1:SUS-ETMX_POS" and "C1:SUS-ITMX_POS"),
and after clicking some blue button on CODAQ_DETAIL,adl screen, the signal from "C1:SUS-ITMX_POS" became
a straight line, while signal from "C1:SUS_ETMX_POS" continued to be a random noise.
I was scared that I made worse for the channels and for Dataviewer, and I started clicking random blue buttons chaotically hoping that it will restore the signal from "C1:SUS-ITMX_POS". Random clicking on arbitrary blue buttons did not return the signal.
As the channel "C1:SUS-ETMX_POS" works normally, I will be measuring Q-factors of ETMX tonight,
but it is obvious that someone else (Rana, Robert,Steve?) needs to restore the correct settings for "C1:SUS-ITMX_POS".
Moreover, as I was clicking chaotically all the blue buttons on CODAQ_DETAIL,adl screen, someone else (Rana, Robert, Steve?) will need to check somehow that I did not destroy signals from some other channels.
I apologize for the negative consequences of my channel adding,
but Rana asked me in the very beginning in September to let others know if I spoil something, so that others would be aware of it and could fix the problem.
Again, I apologize and hope that the problem is not very serious. |
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Thu Jan 24 22:10:49 2008 |
Andrey | Configuration | Computer Scripts / Programs | Problem with channels - help of Rana, Robert or Steve is needed |
I definitely spoiled something (changes some settings) by chaotically clicking those blue buttons (see my previous entry # 260).
Unfortunately, I cannot use standard library of functions for reading from channels from mDV directory.
Although I see the curve of a noise in the Dataviewer from the channel "Ch1:SUS_ETMX_POS", when I try to read data from the channel using the program "get_data" from MDV directory, I get the error message
"Warning: No data available for [numbers representing "gps_start_time" and "gps_end_time"].
In new_readframedata at 136
In new_fetch_shourov at 71
In get_data at 98"
I checked, both gps-times are in the past from now, so as far I understand, nothing is recorded into the channels.
Of course, I added two hours ago to the directory "mDV", that is I used addpath(pwd) in that directory.
And I also cannot run the program that I used on Tuesday evening which takes data from "C1:SUS_ITMX_POS" (no data from that channel), which worked perfectly on Tuesday.
I again apologize for clicking the wrong blue button (see my explanation in my previous message #260). I ask someone who knows how to return normal working of channels (normal interaction of computer and channel memory) to do that.
Before that I cannot take data. I do not know how to restore the initial settings which existed before I started adding the channel to Dataviewer.
Andrey. |
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Thu Jan 24 22:52:18 2008 |
Andrey | Bureaucracy | General | Ants around a dirty glass (David - please read!) |
Dear coleagues,
there are rains outside these days, so ants tend to go inside our premises.
David was drinking some beverage from a glass earlier today (at 2PM) and left a dirty glass near the computer.
There are dozens, if not hundreds, of ants inside of that glass now.
Of course, I am washing this glass.
A. |
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Sat Jan 26 02:34:34 2008 |
Andrey | Update | Computer Scripts / Programs | Overnight Measuremts in XARM |
I am running the program for measuring RMS of peaks in XARM tonight. I just started it, and it will run for about 9 hours until noon on Saturday. Please do not disturb the interferometer. Now the XARM is locked, it should stay locked over the night.
Andrey. |
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Mon Jan 28 17:16:54 2008 |
Andrey | Configuration | Computers | Matlab libraries DO NOT WORK properly sometimes |
Working in Matlab, I encountered at two different times today the license distribution problem:
??? License checkout failed.
License Manager Error -4
Maximum number of users for Curve_Fitting_Toolbox reached.
Try again later.
To see a list of current users use the lmstat utility or contact your License Administrator.
Troubleshoot this issue by visiting:
http://www.mathworks.com/support/lme4a |
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Wed Jan 30 13:09:55 2008 |
Andrey | Update | SUS | New results for XARM (pdf) |
See attachments: pdf-presentation with plots in "true" axes Q_ETMX and Q_ITMX, and seismic backgound measurement.
Results that were shown a week ago turned out to be not sad at all! |
| Attachment 1: New_Results_XARM.pdf
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| Attachment 2: Accel-Seismic_10AM.pdf
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Fri Feb 15 22:16:04 2008 |
Andrey | Update | Computers | MATLAB is not working: "Licence checkout failed" |
For some unknown to me reason,
Matlab stopped working about 20 minutes ago on all computers in the control room (both UNIX control machines and Windows).
It says: "License checkout failed. License Manager Error -15. MATLAB is unable to connect to the license server."
I do not know how to revive Matlab.
At the same time, I consider that I made a significant progress in building my theoretical/computational model in the last 2 days. I was able to compute the time-evolution of accelerometer signals through stacks and pendulums using Matlab command "lsim", and I am now able to calculate RMS of spectrum of differential arm length in different frequency intervals. It seemed to me that everything is ready in my program to make the three-dimensional theoretical/computational plot (RMS as a function of Q-factors of ETMX and ITMX), but unfortunately Matlab stopped working. It seemed to me that all that was remaining was to run a loop with all possible values of Q-factors. Let's hope that Matlab will be working after the weekend.
Andrey. |
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Tue Feb 19 15:21:47 2008 |
Andrey | Update | SUS | Earthquake tripped watchdogs in ETMY, ITMY |
According to the web-page http://earthquake.usgs.gov/eqcenter/recenteqsus/Quakes/ci14351140.php ,
there was a 5.0 earthquake in northern Baja California in Mexico at 02.41PM earlier today.
This earthquake made an effect on our watchdogs for ETMY and ITMY (their currents exceeded maximal values).
Watchdogs for ITMY are now restored back,
and it is taking more time for a "side degree" for ETMY to calm down,
it is still (40 minutes after the kick) swinging a lot with amplitude ~ 200mV. |
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Fri Feb 22 02:51:20 2008 |
Andrey | Update | PEM | Accelerometer ITMX seems to be broken |
As people probably know,
I am trying (for a long time) to create a computational program that calculates the evolution of accelerometer time-domain data through stacks and pendulum transfer functions to test masses, and calculate the RMS of differential arm lenght spectrum.
I noticed on Tuesday that time-domain signals from the two accelerometers (one is near ETMX, the other one is near ITMX) seem to have different amplitudes of fluctuations around the mean value. I suspected that this is the main reason why I cannot get the awaited result of minimum of RMS for equal values of Q-factors for ETMX and ITMX suspensions (because we subtract two very different numbers, so we cannot get anything close to zero). I took amplitude spectra of the accelerometer data (dttfft2), and they look very differently for ETMX and ITMX accelerometers. I believe that spectrum of ETMX accelerometer represents seismic noise, but accelerometer ITMX seems to provide us with irrelevant and wrong data. No peaks, just almost monotoneous decreasing curve, and 10 times smaller amplitude. Therefore, ITMX seems to be broken.
I will try tomorrow to clap my hands, shout, yell, near the broken accelerometer to confirm that the accelerometer is broken (more precisely, that either accelerometer itself is broken,
or cable connections, or DAQ channel, but something is wrong). Now it is very late, and I am going home.
See attached figures: time-scale is 10^(-1), 10^0, 10^1, 10^2 Hz. |
| Attachment 1: Accelerom-EYMX-Feb22.jpg
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| Attachment 2: Accelerom-ITMX-Feb22.jpg
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Fri Feb 22 15:16:33 2008 |
Andrey | Update | PEM | ITMX Accelerometer is NOT broken |
As I wrote in message 330, there was a bad signal from ITMX accelerometer. I have found the reason: the BNC-cable which goes from the black board with switches for accelerometer gain (1,10,100) towards DAQ-tower was completely disconnected from that black board with gain-switches. The end of the long BNC-cable was on the floor. Therefore, it was totally impossible to see any accelerometer signal. The cable that I am writing about should transport the signal from ITMX_X accelerometer.
Now all the BNC-connections seem to be in good shape, and spectra of accelerometers near ITMX and ETMX , both of them are in x-directions, are very much similar. |
| Attachment 1: Accelerom-ITMX-Feb23.jpg
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| Attachment 2: Accelerom-ETMX-Feb23.jpg
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Fri Feb 22 20:42:44 2008 |
Andrey | Summary | Computer Scripts / Programs | It seems I succeeded in theoretical simulations |
I am pretty happy at this moment.
I definitely feel that it took me too much time to understand how to do the Matlab program and how to overcome difficulties,
but eventually at last my Matlab program seems to start working.
Briefly: What the program does?
--> take time-domain signal from two accelerometers near ITMX and ETMX (use 'get_data');
--> calculate the time-evolution of those two signals through the system "stack + pendulum" to the test-masses ITMX and ETMS (use 'lsim' in Matlab),
which gives us the time-domain evolution of the deviation of the position of individual test-mass from its average position.
--> Subtract the two results from each other in time-domain, this gives us the deviation of the length of the XARM-cavity from its average value
(roughly speaking, deviation of the length of the cavity from exactly 40 meters, although I am aware that the exact average length of XARM is less than 40 meters).
--> Take the amplitude spectrum of the result, using Sqrt(pwelch) and calibrate it from "counts" to "meters".
--> Calculate root-mean-square of peaks at different frequency intervals, for example near 0.8Hz,
and plot the three-dimensional surface showing the dependence of RMS on Q-factors Q_{ETMX} and Q_{ITMX}.
Eventually I am able to create these dependences of RMS.
I see that the minimum of the dependence is close to the diagonal corresponding to exact equality of Q_ETMX} and Q_{ITMX}, but not exactly along the diagonal. The plot allows to say
which of two conditions "Q_I > Q_E" or "Q_E < Q_I" should be fullfilled for optimization reasons. My plot is raw, I might have made a mistake in axis-label, I do not garantee now that the axis label "Q_ITMX - Q_ETMX" is correct,
maybe I need to change it for "Q_ETMX - Q_ITMX". I need some more time to determine this on Monday, but clearly there is asymmetry between Q_I and Q_E.
The peak at 0.8 Hz is pretty stable, while the peak at around 3Hz is not very repeatable, therefore in both experimental measurements and these simulations the amplitude of RMS of peak at 3Hz) is several orders of magnitude smaller than for RMS of peak at 0.8Hz, and I do not see minimum somewhere in the RMS-dependence, I see now only steady growth of RMS as Q_factors increase.
I will need to spend some time on Monday trying to understand how the sampling frequency and number of fft-points influence my results when I take amplitude spectrum using pwelch-command, as well I will need to double-check the correctness of normalization from counts to meters (I am not confident right now that amplitude of order of 10^(-12) meters is correct).
So, I need some time after the weekend to analyze my results and maybe make some slight changes, but I am glad that my Matlab model started to work in principle. I wanted to let others know about the status of the progress in my work. The fact that Matlab program works now is a good ending of a week.
Andrey. |
| Attachment 1: RMS_peak_08Hz-Theoretical.png
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| Attachment 2: RMS_peak_08Hz-QI-QE.png
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| Attachment 3: RMS_peak_3Hz-Theoretical.png
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| Attachment 4: RMS_peak_broad-interv-Theoretical.png
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Fri Feb 22 21:19:38 2008 |
Andrey | Bureaucracy | Computer Scripts / Programs | MDV library does not work at "LINUX 2" |
While working on Thursday evening with Matlab scripts "dttfft2" and "get_data", I noticed that mDV library does not work at computer "LINUX 2" (the third computer in the control-room if you enter it from the restroom). There are multiple error messages if we try to run "hello_world", "dttfft2" or "get_data". In order to take data from accelerometers, I changed the computer - I was working from "LINUX 3" computer, the most right computer in the control room, but for the future someone should resolve the issue at "LINUX 2". I am not experienced enough to revive the correct work of mDV directory at "LINUX 2".
Andrey. |
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Tue Feb 26 20:24:04 2008 |
Andrey | Summary | TMI | Sorrow |
| As for that plot of three-dimensional surface, I indeed was wrong with the axis "Q_ETMX-Q_ITMX" (I put there wrong string "Q_ITMX-Q_ETMX"). On Friday plot there were values 10^(-12) on the z-axis, and that should be really meters, but the point that as I realized on Monday, I have never calibrated experimental measurement results from counts to meters , that's why it is this difference between 10^(-6) and 10^(-12). I still did not find the way to compare experim. and theoretical plots, because even if I leave "counts" on both plots, so that I have scale 10^(-6) on both plots, then the change in theoretical plot is just 0.02*10^(-6) for the range of Q-factors change, while the change in experimental measurements is an order of magnitude more 0.4*10^(-6), so the surface for theretical plot would be almost flat in the same axes as experimental results. |
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Tue Mar 25 13:21:25 2008 |
Andrey | Update | Computers | c1susvme2 is not behaving itself again |
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Wed Mar 26 13:41:53 2008 |
Andrey | HowTo | SUS | Modification of ''C1DRIFT_MONITOR'' |
I learned how to modify the drift-monitor in MEDM so that values on it change colors from green to yellow to red depending how much is the fluctuatioin (deviation) of the value from its mean nominal value.
In order to do this, I used the following eight commands:
tdswrite CHANNEL_NAME.HIHI VALUE
tdswrite CHANNEL_NAME.HIGH VALUE
tdswrite CHANNEL_NAME.LOW VALUE
tdswrite CHANNEL_NAME.LOLO VALUE
tdswrite CHANNEL_NAME.HHSV 2
tdswrite CHANNEL_NAME HSV 1
tdswrite CHANNEL_NAME LSV 1
tdswrite CHANNEL_NAME LLSV 2
where CHANNEL_MAME is the name of the channel the value of which is indicated on the MEDM screen C1DRIFT_MONITOR, for example
C1:SUS-MC1_SUSPOS_INMON, and VALUE is numerical value that I assigned to the channel parameters.
By now I modified nine mode-cleaner channels (POS, PITCH and YAW channels for MC1, MC2 and MC3) and 6 channels for ITMX and ITMY.
Note that as we have problems this week with computer C1SUSVM, namely ''c1susvme2'' is not working, indicators for MC2 in the drift-monitor do not change colors today although they should.
In order to judge which values should be established as reasonable deviations from the average nominal values, I was looking into Dataviewer trends for the channels that are in the drift-monitor.
In the future indicators for channels ETMX and ETMY, BS, PRM, SRM should be modified in complete analogy with what I did already for MC and for ITM. So, I have modified 3*5 = 15 channels, and 3*5 = 15 channels are left for the future.
Note that (as far as I understand) instead of commands "tdswrite" it is absolutely legitimate to use commands "ezcawrite". |
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Thu Apr 3 18:33:17 2008 |
Andrey | Summary | Environment | Status of Weather Station |
During the last two days some things related to weather station have been improved.
1) Startup file for the computer (processor) 'c1pem1' was changed so that now 'c1pem1' can be rebooted from "Linux1". Computer 'c1pem1' is responsible for communicating data between 'Weather Monitor' and control UNIX machines. Before April 1st it was impossible to reboot the computer 'c1pem1'. Now 'c1pem1' runs without difficulties.
2) It was determined that some ethernet cables of category "cat 5" were bad. I replaced one short cat 5 cable between 'c1pem1' and 'network-switch board' in the neighboring computer rack, and I still need to replace the internet ending of another long (~20 meters) cat 5 cable after Alex Ivanov will bring the tool for that.
3) 'Weather monitor' and 'WeatherLink' are temporarily moved away from their "nested" positions on the north wall, and they are now in the proximity of processor 'c1pem1'. Thus the signal about "Inside Temperature" goes into 'c1pem1' computer without any additional ethernet cables, and "inside temperature" is correctly displayed on the "Checklist" adl. MEDM screen on the control UNIX machines. The cable with a signal from the roof sensors (which might be dead due their 7-year age) is temporarily disconnected from the 'Weather Monitor'.
Result: 'Weather Monitor' and computer (processsor) 'c1pem1' are alive, they communicate reasonable "Inside Temperature" to the control UNIX-machines.
The fate of the outside sensors is currently unknown, I plan to go to the roof together with Mr. Steve Vass tomorrow and try to determine what should be done with them.
I am also writing (right now) a wiki-40 page which explains what is the "Weather Station" and what is its status. |
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Thu Apr 3 18:46:04 2008 |
Andrey | Configuration | Computers | "Network switch board" and "c1pem1 crate" were touched |
While working with the weather station, I did two things that potentially (with a very small probability) might influence the smooth work of other processors/computers.
I did the following on Wednesday, April 2nd, in times between 1PM and 3PM.
(1) I turned off for several seconds and returned into the initial position the switch-key on the rack with computer (processor) 'c1pem1' in order to reboot processor 'c1pem1'. The turning off/on of that key-switch was repeated several times.
(2) I pulled gently the whole "Network-Switch Board" towards me in order to replace an ethernet cat 5 cable going into the board form the processor 'c1pem1'. Some other connections of other ethernet cables might be flimsy, and then other people in 40-meter might have problems with computers other than 'c1pem1'. It should not happen, but in case of extraordinary behaviour of any other computer in our lab, people should check the connectors on the network-switch board. It is located near the middle of Y-arm. See picture. |
| Attachment 1: Computer_Rack.JPG
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Thu Apr 3 19:27:50 2008 |
Andrey | Summary | Photos | Tour for prospective grad students |
Last Friday (March 28), there was a tour of 40-meter lab for prospective graduate students.
Rana showed to the prospective students the interferometer. See pdf-attachment with pictures (two pictures of Rana with undergraduates (I took them) and two old pictures which I discovered on the memory card of Nikon d-40, it was not me who took those two last pictures). |
| Attachment 1: Rana_Lecturing.pdf
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Fri Apr 4 16:54:06 2008 |
Andrey | Summary | Environment | Weather station is fully alive |
After today's trip to the roof of our building the weather station seems to be completely resurrected!
We went to the roof together with Steve Vass, and we discovered that:
(1) Sensors of wind speed, wind direction and the bowl that measures the amount of precipitation do not have any visible defects, so there is no problem with all those sensors even after being outside for seven years.
(2) We discovered that there are cable junctions located on the roof, and those junctions were located close to the rim (edge) of the roof, before the cables go inside of 40-meter lab room. The taping in the place of the junction was not good due to the age, and the connections between the cables were disrupted (cable endings were out of the connectors). Therefore, no signal from the roof sensors could be transferred to the 'Weather Monitor'. It was not wise from the person who installed the weather station to leave the fragile cable connections outside, on the roof, because the length of the cables allowed to locate those three connectors inside of the building.
See the attached PDF-file with pictures.
(3) After the cables were plugged into the connectors, these cable junctions were gently pulled into the inside of the 40-meter interferometer room. These cable junctions should not be located outside of the building!
Immediately after all the above-mentioned steps, the reasonable indications of outside temperature, humidity, pressure, wind speed and direction appeared on the 'Weather Monitor'.
In order to see if there is any problem of communication between the 'Weather Monitor' and UNIX control computers through 'c1pem1', I rolled out two brand new black cat-5 ethernet cables on the floor of the interferometer room (they are on the floor temporarily, the ethernet cable will go from the floor into the ceiling cable tray eventually), connected the two cables together through freshly purchased from Caltech bookstore cable connectors, and thus connected the 'Weather Monitor' to the processor 'c1pem1'.
Result: Now we can see reasonable indications of outside temperature, pressure, amount of precipitation, wind speed and direction on the EPICS screen! Moreover, these indications are changing with time.
As a reminder for everyone: standard atmospheric pressure is about 101kPa, so the indications of pressure as 99900Pa is quite reasonable.
One thing is not clear for me yet: wind speed on the 'Weather Monitor' is fluctuating between 2 and 4 mph, while MEDM EPICS-screen values are fluctuation in the range between 0 and 3mph.
Many thanks to Steve Vass and Alexander Ivanov for their help. |
| Attachment 1: Work_on_the_Roof.pdf
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