ELOG 40m

End of Daylight Saving Time this weekend

Environment

Useful information for everyone, as a friendly reminder:

According to the web-page

http://www.energy.ca.gov/daylightsaving.html,

this coming weekend there will be the end of Daylight Saving Time.

Clocks will be adjusted backward one hour.

Thu Nov 1 19:53:02 2007

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Thu Nov 1 19:53:34 2007

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Thu Nov 1 19:54:22 2007

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Thu Nov 1 19:55:03 2007

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Thu Nov 1 19:55:59 2007

Andrey, Tobin, Robert - photo

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Thu Nov 1 19:58:07 2007

Steve and Tobin's picture

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Thu Nov 1 20:03:00 2007

Procedure "Drop and Drag" in pictures

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Wed Nov 7 02:14:08 2007

More information about MC2 ringdown

IOO

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

Attachment 2: image-attempt_2.png

Attachment 3: image-attempt_3.png

Attachment 4: image-attempt_4.png

Attachment 5: image-attempt_5.png

Attachment 6: Fit-1st_attempt.jpg

Attachment 7: Fit-5th_attempt.jpg

Attachment 8: 7_Nov_1941-parad-na-krasnoy-ploschadi.jpg

Attachment 9: parad1984-moskva.jpg

130

Wed Nov 28 12:43:53 2007

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.

135

Wed Nov 28 19:02:41 2007

New WIKI-40M page describing Matlab Suspension Modeling

WIKI-40M Update

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.

151

Fri Nov 30 20:17:26 2007

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

168

Wed Dec 5 18:08:36 2007

Optical Lever laser for ETMX is installed

ASC

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

172

Wed Dec 5 23:19:03 2007

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

Attachment 2: Coherence-ZX_East.pdf

Attachment 3: Coherence-ZY_East.pdf

Attachment 4: Power_Sp_WEST.pdf

Attachment 5: Coherence-ZX_West.pdf

Attachment 6: Coherence-XY_West.pdf

Attachment 7: Coherence-YZ_West.pdf

174

Thu Dec 6 15:22:42 2007

Pictures of the inside of He-Ne laser

Electronics

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

Attachment 2: DSC_0228.JPG

176

Thu Dec 6 19:19:47 2007

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.

191

Thu Dec 13 23:56:02 2007

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.

194

Mon Dec 17 23:42:08 2007

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.

195

Tue Dec 18 00:51:39 2007

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

Attachment 2: RMS_3Hz_top_view.png

Attachment 3: RMS_broad_top_view.png

Attachment 4: RMS_08Hz_Qsum-Qdiff-axes.png

Attachment 5: RMS_3Hz_Qsum-Qdiff-axes.png

Attachment 6: RMS_broad_Qsum-Qdiff-axes.png

Attachment 7: RMS_08Hz_Qaxes.png

Attachment 8: RMS_3Hz_Qaxes.png

Attachment 9: RMS_broad_Qaxes.png

Attachment 10: Accel_ITMX.png

Attachment 11: Accel_ETMX.png

198

Tue Dec 18 23:27:36 2007

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.

199

Tue Dec 18 23:41:00 2007

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

Attachment 2: RMS_3HZ_Top_View.png

Attachment 3: RMS_broad_Top_View.png

Attachment 4: RMS_08HZ_Side_View.png

Attachment 5: RMS_3HZ_Side_View.png

Attachment 6: RMS_broad_Side_View.png

Attachment 7: RMS_08HZ_Q_E_Q_I_Axes.png

Attachment 8: RMS_3HZ_Q_E_Q_I_Axes.png

Attachment 9: RMS_broad_Q_E_Q_I_Axes.png

Attachment 10: Accelerometer_ITMX.png

Attachment 11: Accelerometer_ETMX.png

Attachment 12: RMS_broad_Q_E_Q_I_Axes.png

201

Wed Dec 19 15:51:00 2007

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

Attachment 2: RMS-3Hz-Top_View.png

Attachment 3: RMS-broadband-Top_View.png

Attachment 4: RMS-08Hz-Side-View.png

Attachment 5: RMS-3Hz-Side_View.png

Attachment 6: RMS-broadband-Side_View.png

Attachment 7: RMS-08Hz-Q_I-Q_E-Axes.png

Attachment 8: RMS-3Hz-Side_View.png

Attachment 9: RMS-broadband-Side_View.png

Attachment 10: Accelerometer_ETMX.png

Attachment 11: Accelerometer_ITMX.png

202

Wed Dec 19 16:07:37 2007

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}.

Attachment 1: RMS_08Hz_Top_view.png

Attachment 2: RMS_3Hz_Top_view.png

Attachment 3: RMS_broad_Top_view.png

Attachment 4: RMS_08Hz_Side_view.png

Attachment 5: RMS_3Hz_Side_view.png

Attachment 6: RMS_broadband_Side_view.png

Attachment 7: RMS_08Hz_Q_I-Q_E-axes.png

Attachment 8: RMS_3Hz_Q_I-Q_E-axes.png

Attachment 9: RMS_broadband_Q_I-Q_E-axes.png

Attachment 10: Accelerom_ETMX.png

Attachment 11: Accelerom_ITMX.png

204

Wed Dec 19 20:28:27 2007

DAQ

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 Tongue

)

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.

205

Thu Dec 20 02:04:09 2007

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

Attachment 2: RMS-3Hz-Top-View.png

Attachment 3: RMS-broadband-Top-View.png

Attachment 4: RMS-08Hz-Side_View.png

Attachment 5: RMS-3Hz-Side_View.png

Attachment 6: RMS-broadband-Side_View.png

Attachment 7: RMS-08Hz-Q_I-Q_E-Axes.png

Attachment 8: RMS-3Hz-Q_I-Q_E-Axes.png

Attachment 9: RMS-broadband-Q_I-Q_E-Axes.png

Attachment 10: Accelerometer-ETMX.png

Attachment 11: Accelerometer-ITMX.png

208

Thu Dec 20 21:57:34 2007

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

Attachment 2: Accelerom_ITMX.png

209

Thu Dec 20 21:58:28 2007

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.

251

Mon Jan 21 23:30:03 2008

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

256

Wed Jan 23 12:31:36 2008

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

260

Thu Jan 24 20:03:40 2008

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.

261

Thu Jan 24 22:10:49 2008

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.

262

Thu Jan 24 22:52:18 2008

Ants around a dirty glass (David - please read!)

General

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.

273

Sat Jan 26 02:34:34 2008

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.

281

Mon Jan 28 17:16:54 2008

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

286

Wed Jan 30 13:09:55 2008

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

Attachment 2: Accel-Seismic_10AM.pdf

320

Fri Feb 15 22:16:04 2008

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.

323

Tue Feb 19 15:21:47 2008

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.

330

Fri Feb 22 02:51:20 2008

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

Attachment 2: Accelerom-ITMX-Feb22.jpg

336

Fri Feb 22 15:16:33 2008

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

Attachment 2: Accelerom-ETMX-Feb23.jpg

338

Fri Feb 22 20:42:44 2008

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

Attachment 2: RMS_peak_08Hz-QI-QE.png

Attachment 3: RMS_peak_3Hz-Theoretical.png

Attachment 4: RMS_peak_broad-interv-Theoretical.png

339

Fri Feb 22 21:19:38 2008

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.

341

Tue Feb 26 20:24:04 2008

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.

401

Tue Mar 25 13:21:25 2008

c1susvme2 is not behaving itself again

404

Wed Mar 26 13:41:53 2008

HowTo

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".

410

Thu Apr 3 18:33:17 2008

Status of Weather Station

Environment

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.

412

Thu Apr 3 18:46:04 2008

"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

413

Thu Apr 3 19:27:50 2008

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

414

Fri Apr 4 16:54:06 2008