ELOG 40m

ISS dark noise - ground loop enlightenment

PSL

My alleged 60 Hz harmonics were all from a ground loop created by connecting the SR785 ground to the ISS circuit ground; they disappeared when I set the SR785 input to "floating ground." doh!

I modified the ISS PD's to have a 100 ohm resistor in series with the output (in place of 20 ohms). The diodes are again in place on the table, ready for action.

185

Mon Dec 10 18:42:20 2007

I wrote a script to measure the ISS RIN. The script uses the "labca" interface (described in an earlier entry) to read and twiddle EPICS settings and mDV to get DAQ data. The script measures open loop RIN, closed loop RIN at each of several gain slider settings, and dark noise. The dark noise is obtained by misaligning (unlocking) the PMC. The script also compares the whitened and unwhitened spectra for an open loop measurement and performs a fit of a simple pole to find the dewhitening filter.

This is all very exciting, but I don't quite believe the results, since the closed loop RIN seems to bottom out at 2e-7/rtHz regardless of the gain slider setting.

Sample output attached. The script may be found at scripts/PSL/ISS/rin.m.

Attachment 1: rin-20071210-1831.pdf

192

Sun Dec 16 16:52:40 2007

dmass

Computer on the end Fixed

Computers

I had Mike Pedraza look at the computer on the end (tag c21256). It was running funny, and turns out it was a bad HD.

I backed up the SURF files as attachments to their wiki entries. Nothing else seemed important so the drive was (presumably) swapped, and a clean copy of xp pro was installed. The username/login is the standard one.

Also - that small corner of desk space is now clean, and it would be lovely if it stayed that way.

193

Mon Dec 17 11:47:13 2007

alberto

an alternative design for the RFAM monitor's filter at 33Mhz

Electronics

Since the Butterworth turned out o be rather wide-band, I tried an other configuration for the 33 MHz filter. Attached are the simulated transfer function and the measured. As one can see, the measured peak is much broader than expected.

Attachment 1: RFSim99-33MHz.png

Attachment 2: RF99-SimmButterworthPrototype.png

Attachment 3: RFSim99-33MHz-TFplot.png

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

196

Tue Dec 18 16:50:35 2007

tobin

uvex laser safety glasses defective

SAFETY

A few days ago we noticed what appeared to be a blotched, speckled fracturing of the coating of the "UVEX" laser safety glasses. These are the glasses with "transparent" (reflective to 1064nm) lenses and white frames that we keep in a box on top of a filing cabinet in the control room. Today Steve measured the transmission of these glasses and found 80% transmission of 1064nm in several cases.

Do not use the white, transparent "uvex" laser safety glasses until further notice. Steve has hidden them away so that you won't be tempted.

Below is attached a photo of a bad lens.

Attachment 1: bad-glasses.jpg

Attachment 2: bad-glasses-zoom.jpg

197

Tue Dec 18 21:31:31 2007

My measurements of the ISS RIN via the SR785 and via the DAQ disagree considerably. The spectral shapes are very similar, however, so I expect that a constant factor is creeping in somewhere. Measurements taken at the PD DC monitor points using the SR785 attached. There is a lot of excess noise in the 300 Hz - 1 kHz region.

Attachment 1: iss-rin.pdf

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

203

Wed Dec 19 16:40:12 2007

laser safety glasses measured

SAFETY

I measured the coarse transission at 1064nm of the 40m safety glasses today.

12 pieces of UVEX # LOTG-YAG/CO2 light green, all plastic construction, ADSORBANT

3 pieces of 6KG5, Scott colored filter glass type,

individual prescription glasses: alan, bob, ben, jay and steve

7 pieces of dual waveleght glasses

These glasses showed 0.00mW transmission out of 170mW Crysta Laser 1064

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

207

Thu Dec 20 19:10:03 2007

waldman

Stressful reattachment of heater

OMC

Photos may follow eventually, but for now here's the rundown. I scraped the heater clean of the thermal epoxy using a clean razor blade. Then I stuffed a small piece of lint free cloth in the OTAS bore and wrapped the OMC in tin foil. With a vacuum sucking directly from the face of the OTAS, I gently scraped the glue off the OTAS aluminum. I wiped both the OTAS and the heater down with an isoproponal soaked lint-free cloth. I put a thin sheen of VacSeal on the face of the heater, wiping off the excess from the edges with a cloth. Then I clamped the heater to the OTAS using 2" c-clamps from the tombstone back to the heater front, making sure the alignment of the OTAS was correct (connector on the absolute bottom, concentric with the OTAS outer diameter). I added a second clamp, then beaded the outside of the joint with a little bit extra VacSeal, just for kicks. I'll leave it covered at least overnight, and maybe for a day or two.

sam

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

210

Fri Dec 21 20:32:25 2007

I couldn't resist any longer: I plugged in the Prosilica GC 750 GigE camera and took it for a spin. This is the little CMOS camera which sends out video over gigabit ethernet.

There were no difficulties at all in getting it running. I just plugged in the power, plugged in ethernet, and put on a lens from Steve's collection. I downloaded the "Sample Viewer" from the Prosilica website and it worked immediately.

It turns out that "Kirk's" computer has not only a gigabit ethernet card, but a little gigabit ethernet switch. I plugged the camera into this switch. The frame rate is amazing. With the camera under fluorescent lights I thought I saw some wacky automatic gain control, but I think this ~10Hz flicker is aliasing of the 60 Hz room lighting.

I put the camera on the PSL table briefly and tried viewing the image from a laptop over the (54mbs) wireless network. This didn't work so well: you could get a couple frames out of the camera, but then the client software would complain that it had lost communications. It appeared that scattered 1064nm light did show up brightly on the camera image. There is a green ethernet cable currently stashed on the roof of the PSL that appears unused. We can try mounting the gigE CMOS cable in place of one of the CCD video cameras.

I did not try the Linux software.

The camera is currently set up at Kirk's desk, using the cool little tripod Rana got from CyberGuys.

This camera looks very promising! Also, in the test image attached below, a very unusual condition has been documented.

Attachment 1: robs_desk.png

213

Wed Dec 26 15:00:06 2007

Steve mentioned to me that ETMY is still tripping more than ETMX. The attached DV plot
shows the trend of the watchdog sensors; essentially the RMS fluctuations of the shadow
sensors. (note** DV can make PNG format plots directly which are much better than JPG
when making plots and much smaller than PS or PDF when plotting lots of points).

Attachment 1: etm.png

214

Wed Dec 26 15:12:48 2007

It turned out that the ETMY POS damping gain was set to 1.0 while the ETMX had 3.8.

I put both ETMs to a POS gain of 4 and then also set the PIT, YAW and SIDE gains for
ETMY. Let's see if its more stable now.

In the next week or so Andrey should have perfected his damping gain setting technique
and the numbers should be set more scientifically.

215

Thu Dec 27 12:12:02 2007

pkp

Update on GigE Camera

So I finally got the linux software to compile on mafalda. I got the software to dump all the information regarding the camera onto a file. I tried to take a tiff snap and came up empty. So I looked at the configuration file and realized that the camera thinks that the frame-rate is a nan. Am reading up the manual to fix the frame-rate manually and then will attempt to take another snap.

All the files are in a folder called Prosilica in /home/controls/ on mafalda. All the executables are in /home/controls/Prosilica/bin-pc/x86/* . On another note, I am looking for a name for the camera. Any suggestions are welcome.

216

Thu Dec 27 13:08:04 2007

Here's a trend from the last 2 days of ETMX and ETMY. You can see that the damping gain increase
has made them now act much more alike. Problem fixed.

Attachment 1: Untitled.png

217

Thu Dec 27 18:18:56 2007

rana

Computers

Update on GigE Camera

Quote:

Suggestion #1: put this in the target area in a directory called /prosilica/. /home/controls is not backed up.

Suggestion #2: put a readme file in there on any work that was necessary to get it to compile.

Suggestion #3: make a wiki page for the camera with all the info that camera code developers will need

218

Sun Dec 30 02:36:35 2007

So I followed suggestions 1 and 3 so far and have started writing up what all needs to be done in order to compile and use the camera. I wrote a program to ping the camera and get its properties and am working on a program to get an image. The reason why I want to write my own programs to do this, is that it will be easier to reuse and also to compile/use in the first place. The programs currently rest in /cvs/cds/caltech/target/Prosilica/ . Unfortunately I will be away for the next couple of days and will have another update on the 2nd.

220

Thu Jan 3 08:53:55 2008

Rana have corrected sus gain damping setting of ETMY 8 days ago

gain settings: pos, pit, yaw & sd
etmx: 4,2,2,& -16
etmy: 4,2,2,& 50

Attachment 1: sus.jpg

221

Thu Jan 3 09:12:59 2008

Here is MZ trend for one year and 40 days.
Now days it runs out of range on the low side.
This is the weakest link in the psl today.

Attachment 1: mz1y.jpg

Attachment 2: mz40d.jpg

222

Thu Jan 3 09:55:11 2008

etmy sus damping restored

ETMY watch dog was lost at midnight

Attachment 1: etmy12h.jpg

225

Fri Jan 4 08:42:03 2008

ETMY sus damping tripped at 6am this morning
It was reset. We should put an accelerometer to the south end to see
the garbage dumping effect.

Attachment 1: etmy20m.jpg

Attachment 2: etmy120s.jpg

Attachment 3: etmysenV.jpg

226

Mon Jan 7 09:01:39 2008

BS sus damping restored

The BS sus damping was lost at 8am Sunday morning.

Attachment 1: bssdl.jpg

227

Tue Jan 8 15:20:17 2008

[Tobin , Pinkesh]

Finally we got the camera doing something (other than giving out its attributes). The only thing that seems to work so far is a program called AAviewer, which converts the image into an ASCII format and displays it on the screen. If you want to play around with it, log into mafalda (131.215.113.23) via rana.ligo.caltech.edu. Access /cvs/cds/caltech/target/Prosilica/bin-pc/x86/ and there should be a few programs in there, one of which is AAviewer, which requires you to get an IP address (which is 131.215.113.103) for the camera right now. (You can also get the IP information via the ListCameras program). The camera is physically in the 40m near the network rack.

Other programs dont seem to be working and its probably due to the network/packetsize issues. Since linux2 can change its packetsize to a higher number, I will get it to compile on linux2 for now and then give it a shot.

228

Wed Jan 9 10:47:15 2008

fricke

ethernet wiring in office/control room

Computers

The electrical people have been here for three days, installing ethernet cables and drops in the 40m office area, in the old conduits where there was power and 10base2. Soon we will have reliable ethernet connections, instead of relying on switches hanging from the ceiling, etc!

230

Wed Jan 9 20:36:42 2008

Treasure

Money in lab

Go's Desk.

Attachment 1: DSC_0370.JPG

232

Thu Jan 10 10:38:02 2008

etmy damping restored

The IST building onstruction has really started yesterday and continuing today with big heavy ground breaking
machinary. The MC is holding lock and the suspentions are hanging on.

ETMY does not like this.

SUS-MC2_LLPD_VAR monitor is a good indicator of seismic activity on this 12 days plot

Attachment 1: etmysus.jpg

Attachment 2: sustrend16d.jpg

233

Thu Jan 10 12:08:23 2008

Attachment 1: bshopped.jpg

234

Thu Jan 10 13:45:52 2008

So, I have tried to compile the camera files which are in /cvs/cds/caltech/target/Prosilica/examples for the past 2 days now and have been unable to get rid of the following error. (specifically ListCameras.cpp, as it doesnt have any other libraries required, which unnecessarily complicates things)

../../bin-pc/x86/libPvAPI.so: undefined reference to `__stack_chk_fail@GLIBC_2.4'
collect2: ld returned 1 exit status
make: *** [sample] Error 1

I used to get this error on mafalda too, but I had fixed it by installing the latest version of the glibc libraries. Inspite of doing so on linux2, the error still persists. I suspect it had something to do with it being a FC3 machine. My own laptop, which also runs Ubuntu works fine too. The problem with these Ubuntu machines is that they dont let me set the packet sizes to 9 kb which is required by the camera. Linux2 does.

If anyone has any idea how to resolve this issue, please let me know.

Thanks
Pinkesh.

235

Thu Jan 10 15:04:04 2008

illuminator light effect on BS position

The bs chamber illuminator light was turned on this morning and left on.
Earlier on Rana noticed that the bs moved.
I follwed up to see what happened. I turned off oplev servo and tried to recenter on oplev pd
by adjusting pitch and yaw biases. It did not move. I looked at suspention and realized that the
illuminator was still on. I turned it off and to my amazement the the AP spot started flashing

Attachment 1: bssusilum.jpg

236

Fri Jan 11 17:01:51 2008

So, here I detail all the efforts on the GigE so far

(1) The GiGE camera requires a minimum of 9 kb packet size, which is not available on mafalda or on my laptop ( both of which run Ubuntu and the Camera programs compile there). The programs which require smaller sizes work perfectly fine on these machines. I tried to statically compile the files on these machines so that I could then port them to the other machines. But that fails because the static libraries given by the company dont work.

(2) On Linux2, which lets me set a packet size as high as 9 Kb, it doesnt compile because of a GLIBC error. I tried updating the glibc and it tells me that the version already existing is the latest ( which it clearly is not). So I tried to uninstall GLIBC and reinstall it, but it wont let me uninstall (it == rpm) glibc, since there are a lot of dependencies. A dead end in essence.

Steps being taken

(1) Locally installing the whole library suites on linux2. Essentially install another version of gcc and g++ and see if that helps.
(2) IF this doesnt work, then the only course of action I can take is to cannibalize linux2's GigE card and put it on mafalda. ( I need permission for this Smile

).

Once again any suggestions welcome.

237

Mon Jan 14 14:41:09 2008

etmy sus damping restored & mz relocked

Tree days trend of MZ HV drift is typical these days.
So as the etmy sus inability to hold damping for longer then 2-3 days.

Attachment 1: etmysus&mzhvtrend.jpg

239

Tue Jan 15 13:15:27 2008

They're throwing concrete around at the construction site.

240

Wed Jan 16 14:06:24 2008

rob, tobin, johnnie

We did some locking work monday night, with decent progress. Working in the PRFPMI style, we managed to get through the part of the script that hands off the offset-CARM DOF to the MCL, but were not successful in engaging the AO path.

We also confirmed the problem with tdsread which prevent it from reading from multiple TLS (Three Lettered Subsystems) at the same time. Tobin traced this to a problem with the ezca library which tds uses, but it's not clear how to fix it. For now we just split the tdsread calls so that there are no multiple TLS calls. Tobin will report further on this.

241

Wed Jan 16 14:09:45 2008

I got a little further with the locking (PRFPMI) last night, after discovering that the cable going from the CM board to the MC board was unplugged at the MC side. This explains why we weren't able to engage the AO path last night. Tonight, I got up to the point where DARM is handed off to OMC transmission, a step which repeatedly failed.
Eventually I realized that although all the lights are the green, the OMC Trans signal was not being updated in the LSC's memory. I suspect this is because the c1ass machine was powered down. Work continues.

242

Wed Jan 16 18:24:41 2008

Because Steve keeps complaining about ETMY, I looked at some minute trend to see if there was something exotic happening at that time. It looks like there is some tremendous seismic activity to make it happen.

The trend shows that there is nothing special happening on the ETMX accelerometer or the ETMX suspension. At the same time, however, there is a huge jump in the ETMY sensors and therefore the watchdog signal. Whenever the watchdog value goes above 140, it trips.

After Andrey moves some accelerometers over to the Y end we can see the effect more directly.

Attachment 1: A.pdf

244

Thu Jan 17 14:13:20 2008

Incremental progress on locking yet again. This time the handoff of DARM to the OMC worked, and progress halted at handing off control of the common mode to REFL166.

245

Thu Jan 17 15:11:13 2008

1) I can statically compile the ListCamera code (which basically just goes out and finds what cameras are connected to the network) on Malfalda and use that compiled code to run on Linux2 without a problem. Simply needed to add explicit links to libpthread.a and librt.a.
(i.e. -Bstatic -L /usr/lib/ -lpthread -Bstatic -L /usr/lib -lrt)

With appropriate static libraries, it should be possible to port this code to other linux machines even if we can't get it to compile on the target machine itself.

2)I've modified the Snap.cpp file so that it uses a packet size of 1000 or less. This simply involves setting the "PacketSize" attribute with the built in functions they provide in their library. After un-commenting some lines in that code, I was able to save tiff type images from the camera of up to 400x240 pixels on Malfalda. The claimed maximum resolution for the camera is 752x480, but it doesn't seem to work with the current setup. The max number of pixels seems to about 100 times the packet size. I.e. packet size of 1000 will allow up to 400x240 (96000) but not 500x240 (120,000). Not sure if this is an issue just with snap code or the general libraries used.

3)Will be working towards getting video running over the next day or so.

246

Thu Jan 17 18:22:14 2008

Alberto

RF Monitor Band-pass Filter

Electronics

After we finalized the schematic for the RF monitor board based on buffered LC resonators, on Richard Abbott's suggestion to avoid the complication brought in by the fast op-amps, we gave another chance to the a passive configuration of the band-pass filter based on a Chebyshev topology. Rich and Ben gave me an old but very powerful software tool to design that kind of filters and showed me the way to circumvent many hassles in making RF test boards.

I made a test circuit for the 166MHz line (see attached schematic), using tunable inductors. The TF are also attached.
We get more than 20 dB of isolation after 33MHz (with a loss of only few dB at the resonance - it could be less), which is enough for all the other frequencies (33,133,199 MHz) but we would like more for the 166. We are going to add one or two extra orders to the filter.

We also have to understand the spike at about 320Mhz and eventually somehow get rid of it.

Alberto

Attachment 1: RF166Mhz.png

Attachment 2: Chebyshevb.png

Attachment 3: Chebyshev2b.png

247

Thu Jan 17 20:50:55 2008

Sam, John, and I matched the beam from an NPRO into a fiber on the SP table today. In doing so we used our GigE camera for a physics application for perhaps the first time, viewing the transmitted mode from the fiber during initial alignment. (I used my laptop running Windows and a 100 megabit switch.)

248

Fri Jan 18 11:53:50 2008

Alberto

RF Monitor Band-pass Filter

Electronics

The response is asymmetric and on the left side of the peak, we have at least 33dB within 33Mhz, which is enough for all the frequencies. We probably don't need an higher order filter but just low pass filters in series.

The spike at 320MHz doesn't depend on the circuit board. It's either the cables, their connection, or the splitters.

Note that the frequency of this test circuit has still to be tuned exactly at 166MHz (now it's 149).

Alberto

Quote:

Attachment 1: Chebyshevb.png

249

Fri Jan 18 15:31:47 2008

rob, johnnie, andrey

On Thursday night we got the intereferometer fully locked in a power-recycled FPMI state. The obstacles included the REFL166 phase being wrong by 180 deg (because that's the correct phase for DRMI locking) and getting confused (again) by the "manual" mode dewhite switching at the ETMs. After turning on the dewhites and the MICH correction, we took the noise spectrum below.

Attachment 1: DARMnoise080118.png

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

252

Tue Jan 22 02:33:45 2008

0) The ETMY oplev needs work/centering

1) recentered DRMI oplevs

2) Did some light DRMI locking. Looked at the loops and the DD signals. The PODD signals look flaky; the beam may not be on the diode. MICH and PRC handoffs to DD signals were spotty, but not a total disaster. Changed the PD9 phase by 115 degs. Work continues on the DD_handoff subscript.

3) John says "There are ants everywhere."

4) Andrey is now versed in the arts of decimation.

253

Tue Jan 22 13:11:03 2008

tobin

ASC

ETMY oplev recentered

The light wasn't even on the diode.

254

Wed Jan 23 09:27:55 2008

etmy sus damping restored

Seismis event trips etmy

Attachment 1: etmysus.jpg

255

Wed Jan 23 11:41:06 2008

Led - acid car batteries were overcharged in the machine shop next door
and sulfuric acid smell is coming over to the ifo room.

Entry room 103 is specially bad.

258

Thu Jan 24 11:52:56 2008

the mud is cleaned up & MOPA shutter is opened

PEM

Safety glasses are required again!

I have just opened the mopa shutter.
One janitor came to help with muddy floor.
Rack 1x1 toward ITMX chamber and the south wall of these area
were completely covered by mud. I wiped the floor of bottom of the rack
with towels. The cables were lifted and still should be wiped.

The bottom of LSC rack got less water, only on the west side.

We are ready to bring up the computers.

Thanks to ALL with the clean up, including Alan Rice
who was really helpful.

264

Fri Jan 25 09:22:21 2008