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ID Date Authordown Type Category Subject
  169   Wed Dec 5 18:22:03 2007 tobinUpdatePSLISS dark noise
Attached is a plot of the dark noise spectrum of the ISS photodiodes (1) before fooling with them, (2) after replacing the 4151's with 4131's (improvement!), and (3) after replacing the cables and changing the wiring (disaster!).
  171   Wed Dec 5 20:32:51 2007 tobinUpdatePSLISS dark noise
The ISS dark noise is not coming from the PD heads; the spectrum is essentially unchanged when the PD is unplugged from the ISS. Did the input opamps both get semi-fried in the same way? (They worked so well when they were first installed.) What else changed? I'm baffled. Frown
  177   Thu Dec 6 19:30:43 2007 tobinUpdatePSLISS dark noise - 60 Hz!
A higher resolution spectrum [attached] shows that nearly all of the excess dark noise on the ISS is in 60 Hz harmonics (with some 256 Hz harmonics too--are these from the DAQ?).

With the loop closed and the slider at 5dB, the laser light coming out has a noise floor of 10^-7 RIN or better from 40 Hz to 8 kHz.

Now to figure out why all this 60 Hz is getting in... (I tried turning off all the lights and the HEPA, and moving the SR785 further away, none of which did anything.)
  181   Fri Dec 7 18:28:30 2007 tobinUpdateComputer Scripts / Programscompiled matlab hoses itself
Andrey pointed out to me that some matlab functions in the Signal Processing Toolbox were dying with errors. Looking into the .m file (identified using the "which" command), I was surprised to see binary garbage rather than glistening, clear Matlab prose. Then I noticed the directory in which it was finding the .m file:
>> which decimate
/cvs/cds/caltech/apps/mDV/extra/linetrack_c_mcr/toolbox/signal/signal/decimate.m
See that "linetrack_c_mcr" directory? This is what is generated when a "compiled" (grumble) Matlab program is run--it decompresses itself into a subdirectory containing weird semi-compiled binary .m files. Unfortunately this is somehow getting incorporated into the matlab path. (I assume there is something in mDV that says "put all subdirectories into the path.")

I hate the Matlab compiler.
  182   Fri Dec 7 18:31:30 2007 tobinUpdateComputer Scripts / Programscompiled matlab hoses itself
Addendnum. The reason the linemon_mcr command was in the path was because of the user issuing the command "addpath(genpath(pwd))" where genpath(D) "returns a path string starting in D, plus, recursively, all the subdirectories of D."

The Matlab compiler is still bad, however.
  183   Fri Dec 7 19:14:30 2007 tobinUpdatePSLISS dark noise - ground loop enlightenment
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 tobinUpdatePSLISS RIN script
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.
  186   Mon Dec 10 19:08:03 2007 tobinConfigurationPSLMZ
The MZ seems finicky today--it keeps unlocking and relocking.

I've temporarily blocked one of the MZ arms while I work on the ISS.
  187   Mon Dec 10 20:35:59 2007 tobinConfigurationComputer Scripts / Programsautolocking scripts
I added this tidbit of csh code to the MZ autolocker to prevent multiple copies from running (on one computer):
if (`pgrep lockMZ | wc -l` > 1) then
   echo lockMZ is already running! 
   exit
endif
Similarly, here's some bash code that does something similar; I'll add it to the other autolocker scripts:
if                                                                                                                       
  pgrep `basename $0` | grep -v $$ > /dev/null                                                                           
then                                                                                                                     
  echo Another copy of this program is already running.  Exiting!                                                        
  exit 1                                                                                                                 
fi
This code searches for all processes with the same name as this script ($0) and then use grep to exclude (-v) the current process ID ($$).
  189   Wed Dec 12 22:24:48 2007 tobinFrogsPEMweather station
I poked at the weather station briefly this evening.

* There's almost nothing in the elog about it.
* It exists. It is located on the North wall, just north of the beam splitter.
* It seems to be displaying reasonable data for the indoors, but nothing for the outdoor sensors.
* c1pem didn't seem to be starting up (couldn't telnet into it, etc). I altered its startup file and reset it several times, and eventually it came to life.
* the weather station has a serial cable that goes all the way to c1pem. I plugged it in.
* however, the Weather.st program complains "NO COMM"--it gets no data from the weather station
* The next thing to do is to plug in a laptop to that serial cable and see if the weather station can be convinced to talk.
  196   Tue Dec 18 16:50:35 2007 tobinUpdateSAFETYuvex laser safety glasses defective
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.
  197   Tue Dec 18 21:31:31 2007 tobinUpdatePSLISS RIN
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.
  210   Fri Dec 21 20:32:25 2007 tobinUpdatePhotosGigE camera
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.
  211   Sat Dec 22 00:52:57 2007 tobinConfigurationPSLISS surgery
In an attempt to quell oscillations in the (unused) outer loop portion of the ISS, I shorted the "PD+" and "PD-" signals from the (nonexistent) outer-loop diodes, and soldered in 47pf compensation capacitors in C92 and C220. This seems to have eliminated oscillations seen at TP41 and TP42. There's still something amiss at TP30 and maybe TP20. Otherwise, the ISS seems happy. I can turn the gain slider to +15dB without saturation (with the HEPA off), though there seems to be less light on the diode (~3.9V) than a week or two ago.
  212   Sat Dec 22 15:32:11 2007 tobinAoGEnvironmentants
Ants are everywhere: on the PSL table, on the circuit board I'm soldering...

I believe I have discovered their energy source.
  219   Wed Jan 2 11:38:56 2008 tobinSummaryWIKI-40M Updatewiki spam
Our wiki keeps getting spammed. It turns out that you can upload attachments without a password, which is a bug. I'll ask David Barker whether there's a fix for this.
  231   Thu Jan 10 00:12:01 2008 tobinSummaryLockingDR
[John, Tobin, Rana]

1. We found SUS_BS_SENSOR_UL to have a ratty signal and low DC value. Twiddling the cables at the BS satellite amplifier and vacuum feedthrough brought the signal back (to 0.667V), but it is still spiky, spiking up to a couple times per second. Rana suggested that these spikes might be scattered YAG laser light (as hypothesized in August). The spikes go away when we misalign the PRM or either ITM, and when we unlock the mode cleaner, lending credance to this theory. SUS_BS_SENSOR_UR also spikes, but much less frequently. We turned off C1:SUS-BS_ULSEN_SW2 and continued.

2. After dither alignment the oplev beams were centred and we were able to lock DRM plus either arm reliably (however locking in this state broke ./drstep_bang at the first ``Going DD''). We ran scripts/DRFPMI/bang/nospring/drdown_bang and were subsequently able to lock DRFPMI (i.e., full IFO) a couple times.

3. To do: Debug ./drstep_bang with just the DRM (no arms).
  238   Mon Jan 14 23:11:26 2008 tobinConfigurationGeneralfiber
John and I removed the fiber that ran from the SP table to the cleanroom. We plan to build a MZ interferometer with this fiber inserted into one of the arms, for the purpose of measuring its phase noise.
  239   Tue Jan 15 13:15:27 2008 tobinUpdateEnvironmentlots of noise
They're throwing concrete around at the construction site.
  243   Wed Jan 16 19:57:49 2008 tobinConfigurationPhotosISCT_EX
Here's a photo of the ISCT_EX table, for the purpose of planning our auxiliary laser arm locking scheme. Note the (undumped!) beam from the beamsplitter before QPDX (the leftmost gold-colored box); perhaps we could inject there.
  247   Thu Jan 17 20:50:55 2008 tobinUpdateGeneralfiber coupling
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.)
  250   Fri Jan 18 20:53:56 2008 tobinConfigurationGeneralETMY oplev
I monkeyed around with the ETMY oplev, adding a folding mirror and moving the HeNe so that John, Sam, and I have more room for our auxiliary laser setup. (The ISCT-EY has more room than ISCT-EX; the latter has an extra photodiode for IP ANG.) I believe I successfully recommissioned the oplev, though it might not be up to the SV standard. I verified that wiggling the ETMY alignment sliders showed corresponding wiggles in the oplev signals. However, it seems poorly diagonalized.

Our current plan is to have an NPRO, EOM, and fiber coupler on the SP table. This fiber will take light to ISCT-EY where we'll have a mode-matching telescope and inject light to the Y arm via a polarized beamsplitter. This auxiliary beam will have polarization orthogonal to the beam from the PSL.
  253   Tue Jan 22 13:11:03 2008 tobinUpdateASCETMY oplev recentered
The light wasn't even on the diode.
  277   Sun Jan 27 13:13:21 2008 tobinMetaphysicsGeneraldeparture
It's been grand. Thanks for having me!

GWAVES IN '08!

Sugar napoleons may be forwarded to T. F., c/o LLO, P.O. Box 940, Livingston, LA 70754-0940.
  498   Sun May 25 21:14:14 2008 tobinConfigurationComputersEPICS proxy server
I set up an EPICS gateway server on Nodus so that we can look at 40m MEDM screens from off-site.
The gateway is set up to allow read access to all channels and write access to none of them.

The executable is /cvs/cds/epics/extensions/gateway; it was already installed. A script to start
up the gateway is in target/epics-gateway. For the time being, I haven't set it up to start itself
on boot or anything like that.

To make it work, you have to set the environment variable EPICS_CA_ADDR_LIST to the IP address of
Nodus. For instance, something like this should work:

setenv EPICS_CA_ADDR_LIST 131.215.115.52

On Windows you can set up environment variables in the "System" Control Panel. On one of the tabs
there's a button that lets you set up environment variables that will be visible to all programs.

On Andrey's machine I installed the Windows EPICS extensions, i.e. MEDM and its friends. I also
installed the cool Tortoise SVN client which lets you interact with SVN repositories through
the windows explorer shell. (The right-click menu now contains SVN options.) I checked out
the MEDM directory from the 40m SVN onto the desktop. You should be able to just right-click in
that window and choose "SVN Update" to get all the newest screens that have been contributed to
SVN; however, there are currently some problems with the 40m SVN that make that not go smoothly.

At the moment on Andrey's (Windows) machine you can go into the MEDM folder and double-click on
any screen and it will just work, with the exception that not all the screens are installed
due to SVN difficulties.
  500   Tue May 27 16:24:54 2008 tobinConfigurationComputer Scripts / Programsndsproxy
The NDS Proxy is a program that accepts NDS (LIGO Network Data Server) connections from the internet and relays them to
our internal frame-builder, so that you can get DAQ and test-point channel data from off-site.

I stopped the ndsproxy that was running on rana and started it on nodus, its new home. This will be
documented in the wiki.

So far I haven't found a mechanism by which the ndsproxy was restarted automatically on rana. Has it just been
restarted by hand?

The ndsproxy stuff lives in target/ndsproxy. Restarting it seems to be just a matter of running "start_ndsproxy" in
that directory.
  508   Fri May 30 21:30:15 2008 tobinConfigurationComputerssvn on solaris
I installed svn on op440m.  This involved installing the following packages from sunfreeware:

apache-2.2.6-sol9-sparc-local  libiconv-1.11-sol9-sparc-local   subversion-1.4.5-sol9-sparc-local
db-4.2.52.NC-sol9-sparc-local  libxml2-2.6.31-sol9-sparc-local  swig-1.3.29-sol9-sparc-local
expat-2.0.1-sol9-sparc-local   neon-0.25.5-sol9-sparc-local     zlib-1.2.3-sol9-sparc-local
gdbm-1.8.3-sol9-sparc-local    openssl-0.9.8g-sol9-sparc-local

The packages are located in /cvs/cds/caltech/apps/solaris/packages.  The command line to install
a package is "pkgadd -d " followed by the package name.  This can be repeated on nodus to get
svn over there.  (Kind of egregious to require an apache installation for the svn _client_, I 
know.)
  510   Sun Jun 1 19:39:35 2008 tobinConfigurationComputerselog, etc
Phil Ehrens gave me a DVD of the 40m elog, apache, and (Jamie's) SVN archive.
I copied it to nodus:/home/controls/dvd-from-ehrens.  Once we get the elog
running on nodus, we can copy the datafile over again from dziban (so that
we don't lose any elog entries) and switch over.
  513   Tue Jun 3 10:19:45 2008 tobinConfigurationComputersbig machine
Several of us transported the big new awesome Sun box from Bridge over to
the 40m last week. If I recall correctly, it's a SunFire X4600 with
something like sixteen 64-bit AMD processor cores at 2.8 GHz. It sounds
like a jet engine when it starts up (before the cooling fans are throttled
back) and has four power supplies (each with its own connection
to the wall). It has slick removable hard disks and fan units too. Our
working name for it is "megatron".

Anyway. It came with two hard disks, one with Solaris 10 installed. I took
the other hard disk over to Alex, who copied a Realtime Linux installation
onto it. Alex says it boots and runs fine.

It remains for you guys to install the machine onto rails and install the
whole thing into a rack. Before it goes into service as a realtime control
machine, you might as well install Matlab on it and do some heavy-duty
computation.

  514   Tue Jun 3 10:40:27 2008 tobinConfigurationComputersnew dataviewer
Alex let me know the secret location of the latest dataviewer executable for Linux. It is:

http://www.ligo.caltech.edu/~aivanov/upload/dv/Control/dc3

If your linux dataviewer on linux2 has the "year field not filled in" bug, you should download this into /usr/local/bin/dc3 (after making a backup of that file).

It looks like there's no dataviewer installed on rosalba yet. We should figure out a better directory layout for the linux machines; currently dataviewer is installed locally on linux2. It should be in /cvs/cds/caltech/apps/linux/something so that all the linux machines see the same installation.
  636   Sun Jul 6 16:17:40 2008 tobinHowToComputersSVN
I was able to check out the 40m SVN here in Livingston using this command:

svn co svn+ssh://controls@nodus.ligo.caltech.edu/cvs/cds/caltech/svn/trunk/medm

As you might guess, this uses ssh in place of the web server (which we don't have yet).
  340   Sun Feb 24 10:51:58 2008 tfFrogsEnvironment40m in phdcomics?
  14110   Sat Jul 28 00:45:11 2018 terra, sandrineSummaryThermal CompensationHeater measurements overview

[Sandrine, Koji, Terra]

Summary: We completed multiple scans at different heating powers for the reflector set up, observing unique HOM peak shifts of tens of kHz. We also observed HOM5 shifts with the cylinder set up. Initial Lorentzian fittings of the magnitude give tens of Hz resolution. I summarize the main week's work below. 

Set-up

Heater set-up is described in several previous elogs, but attachments #1 and #2 show the full heater set-up and wiring/pinouts in and out of vacuum, since we're all intimately aware of how confusing in-vacuum pinouts can be. We are not using the Sorenson power supply (as described in 14071); we just have the BKPrecision power supply 1735 sitting next to the ETMY rack and are manually going out to turn on/off. 

We've continued to use the scan setup described in elog 14086, which is run using /users/annalisa/postVent/AGfast.py. Step by step notes for setting up the scan, running the scans, and processing the scans are attached in notes.txt.

Inducing/witnessing HOMs

The aux input beam was already clipped and on wednesday (after Trans was centered, 14093) we also clipped the output aux beam with razor blade (angled vertically and horizontally, elog 14103) before PDA255; we clipped ~1/3 of the output beam. Attachment #3 shows before and after clipping output, where orange 'cold' == unclipped, black 'mean' == clipped (all in cold state). Up to HOM5 is visible. 

Measurements

Below is a summary of the available scan data. We also have cold (0A) scans CAR-HOM5 and full FSR scans for most configurations. 

Elliptic Reflector
current[A] voltage[V] power[W] scans
0.4 2 0.8 CAR-HOM3(x1)
0.5 3.4 1.7 CAR-HOM3(x1)
0.6 5 3.0 CAR-HOM3(x1)
0.8 9.4(9.7) 7.5(7.8) CAR-HOM5(>x5)
0.9 12 10.8 CAR-HOM5(x4)
1.09 17 18.5 CAR-HOM3

 

 

 

 

 

 

 

Cylinder + Lenses
current[A] voltage[V] power[W] scans
0.9 15 13.5 CAR-HOM5(odds x4)

We tried the cylinder set-up again tonight for the first time since inital try and can see shifts of HOM5 - see attachment #5; we haven't looked in detail yet, but it looks like odd modes are more effected, suggesting the ring heat pattern is off centered from the beam axis. 

Scan data is saved in the following format: users/annalisa/postVent/scandata/{reflector,cylinder}/{parsed,unparsed}/{CAR,HOM1,HOM2,HOM3,HOM4,HOM5}{_datetime}{_parsed,_unparsed}.{txt,pdf}

Minimum heating

On 7/26 we increased the power to the elliptical reflector heater in steps to find the minimum heater power required to see frequency shifts with our measurement setup. Lowest we can resolve is a shift in HOM3 with 1.7W (0.5A/3.4V). According to Annalisa's measurements in elog 14050, this would be something like 30-60 mW radiated power hitting the test mass. We only looked at CAR - HOM3 for this investigation; data for scans at 0.4A, 0.5A, 0.6A is available as indicated above.

Lorentizian Fitting

The Lorentzian fitting was done using the equation a + b / sqrt(1+((x-c)/d*2), where a = constant background, b = peak height above background, c = peak frequency, d = full width at half max. 

The fitting is still being edited and optimized. We will crop the data to zoom in around the peak more.

The Lorentzian fit of the magnitude shows ~10Hz of resolution. (See attachment 6 for the carrier at 8A and attachment 7 for HOM 1 at 9A)

We're working on fitting the full complex data.

 

 

  14105   Thu Jul 26 01:52:01 2018 terraUpdateThermal Compensationheater work update

Just a quick update: over the past few days we've taken (at least) 5 scans around each peak [carrier - HOM3] at 9.4V/0.8A, 4 scans around [carrier - HOM5] at 12V/0.9A hot state with the reflector setup. We also have (at least) 5 scans of carrier - HOM5 in cold state. I attach a rough overview of the peak magnitude shifts in the first attachment. Analysis ongoing. All data stored in annalisa/postVent/{date}

Initial shifts just based on rought peak placement in the meantime:

            [9.4V/0.8A]   [12V/0.9A]

HOM1    10 kHz         20 kHz

HOM2    18 kHz         28 kHz

HOM3     30 kHz        40 kHz

HOM4     N/A             26 kHz

HOM5     N/A             35 kHz

I also attach the heating thermal transient from today (12V/0.9A) as seen by the opLevs. We see a shorter time constant for pitch, longer for yaw, preceeded by a dip in yaw. Similar behavior yesterday for slightly less heating, though less pronounced pre-dip. The heater is offcentered on the optic horizontally; likely this is part of the induced yaw. The spikey stuff i removed is from people walking around inside during the transient.

I've left the heater and LSC off for the night. Heater off at 2:07 am local time.

Please don't touch the oplevs; we're taking a cool down measurement.

  3570   Mon Sep 13 22:51:07 2010 tara,valeraConfigurationPSLbeam scan for RCAV

On Friday, Valera and I calculated the modematching for reference cavity from AOM.

We scan the beam profile where the spot should be.

The first beam waist in the AOM is 103 um, the lens (f= 183 mm, I'm not sure if I have the focal length right) is 280 mm away.

The data is attached. The first column is marking on the rail in inches,

the second column is distance from the lens, the third and fourth column are

vertical and horizontal spot radius in micron. Note that the beam is very elliptic because of the AOM.

  3210   Tue Jul 13 21:04:49 2010 tara,ranaSummaryPSLTransfer function of FSS servo

 I measured FSS's open loop transfer function.

For FSS servo schematic, see D040105-B.  

4395A's source out is connected to Test point 2 on the patch panel.

Test Point 2 is enabled by FSS medm screen.

"A" channel is connected to In1, on the patch panel.

"R" channel is connected to In2, on the patch panel.

the plot shows signal from A/R.

Note that the magnitude has not been corrected for the impedance match yet.

So the real UGF will be different from the plot.

 

-------------------------

4395A setup

-------------------------

network analyzer mode

frequency span 1k - 10MHz

Intermediate frequency bandwidth 100Hz

Attenuator: 0 for both channels

Source out power: -30 dBm

sweep log frequency

------------------------------

medm screen setup

-----------------------------

TP2: enabled

Common gain -4.8 dB

Fast Gain 16 dB

  3163   Wed Jul 7 00:15:29 2010 tara,RanaSummaryPSLpower spectral density from RefCav transmitted beam

I measured the RC transmitted light signals here at the 40m. I made all connections through the PSL patch panel.

Other than two steering mirrors in front of the periscope, and the steering mirror for the RFPD which were used to steer

the beam into the cavity and the RFPD respectively, no optics are adjusted.

We re-aligned the beam into the cavity (the DC level increased from 2 V to 3.83V) (Fig2) (We could not recover the power back to what it was 90 days ago)

and the reflected beam to the center of the RFPD.

 

I measured the spectral density of the signal of the transmitted beam behind RefCav in both time and frequency domain.

This will be compared with the result from PSL lab later, so I can see how stable the signal should be.

I did not convert Vrms/rtHz to Hz/rtHz because I only look at the relative intensity of the transmitted beam which will be compared to the setup at PSL lab. 

 

 

 We care about this power fluctuation because we plan to measure

 photo refractive noise on the cavity's mirros

(this is the noise caused by dn/dT in the coatings and the substrate,

the absorption from fluctuating power on the coating/mirror changes

the temperature which eventually changes the effective length of the cavity as seen by the laser.)

      

      The plan is to modulate the power of the beam going into the cavity,

the absorption from ac part will induce frequency noise which we want to see.

Since the transmitted power of the cavity is proportional to the power inside the cavity.

 Fluctuations  from other factors, for example, gain setting,  will limit our measurement. 

That's why we are concerned about the stability of the transmitted beam and made this measurement.


 

  3812   Thu Oct 28 19:10:26 2010 taraUpdateElectronicsTTFSS for 40m

I keep a set of new TTFSS for 40m in electronic cabinet along the North arm.

The set number is #6. It is working and has not been modified by me.

Other two sets,# 5 and #7, are kept at PSL lab.

  4512   Mon Apr 11 20:03:05 2011 taraUpdateElectronicsTTFSS for 40m

I brought TTFSS set #7 to 40m and kept it in the electronic cabinet.

note that Q4 transistor has not been replaced back to PZT2907A yet. It's still GE82.

Q3 is now pzt3904, not PZT2222A.

 

  6514   Tue Apr 10 11:08:29 2012 taraUpdatePSLcurved mirror behind AOM removed

We removed the curved mirror behind the AOM (ROC=0.3m) on PSL table. The mirror is now in PSL lab. See PSL:905 for more detail.

  7904   Wed Jan 16 10:57:37 2013 taraSummaryIOONoise budget for MC

I calculated thermal noise in mode cleaner (MC) mirrors and compared it with the measured MC noise. Thermal noise won't be a significant noise source for MC.

== Motivation==

 There is an idea of using MC and a refcav to measure coating thermal noise. One laser is frequency locked to MC, another laser is locked to an 8" refcav. Then the two transmitted beams are recombined so that we can readout the frequency noise. In this case, the transmitted beam from MC is a better reference (less frequency noise) than the beam from refcav. However, we need to make sure that we understand the noise sources, for example brownian noise, thermoelastic noise in both substrates and coatings, in MC more thoroughly.

==Calculation==

I used Rana's code for MC's technical noise sources from, svn. The same plot can be found in appendix C of his thesis. Then I added my calculation to the plot.  Jenne pointed me to 40m:2984 for the spot size and the cavity length. The spot radius on MC1 and MC3 is ~ 1.5mm, and ~3.4 mm@MC2, The round trip length is ~27m, thus the frequency fluctuation due to thermal noise is lower than that of refcav by 2-3 orders of magnitude. I calculated Brownian noise in coatings, Brownian noise in substrate, Thermoelastic noise in substrate. I assumed that the coatings are SiO2/Ta2O5, quarter stacks, coatings thickness for MC1/3 = 5um, for MC2 = 8um. The code can be found in the attachment.

mc_nb_TN.png

==result==

Total thermal noise on MC (Brownian + Thermoelastic on substrate and coatings of MC1-MC3) is plotted in dashed red. It is already below 10^-5 Hz/rtHz at ~20 Hz. This is sufficiently low compared to other noise sources. Beat signal from CTN measurement with 8" cavities is plotted in pink, the estimated coating brownian noise is plotted in a yellow strip. They are well above the measured MC noise between 100 Hz to a few kHz. Measuring coating thermal noise on 8" refcav seems plausible with this method. We can beat the two transmitted beams from IMC and refcav and readout the beat signal to extract the displacement noise of refcav. I'll discuss this with Koji if this is a good surf project.

 mc_nb_TN_2013_01_18.png

[the internal thermal noise in the original plotted is removed and replaced with the total thermal noise plot instead]

 note:I'm not sure about the current 40m MC configuration. The parameters used in this calculation are summarized in mcnoiseS2L1.m (in the svn page).

 

  7950   Mon Jan 28 21:36:44 2013 tall guyFrogsGeneralsmall people on notice

If I catch anyone putting small booties into the large bootie bin, I will make said person eat small booties.

  4371   Wed Mar 2 22:57:57 2011 sureshSummaryGeneralStuff from LLO

Here is a partial list of stuff which is being packed at LLO to be shipped to CIT.  The electronics ckt boards are yet to be added to this list.  Will do that tomorrow.

 

 

  4381   Mon Mar 7 17:58:14 2011 sureshSummaryGeneralStuff from LLO

Here is the updated list. These lists were used as packing lists and therefore are organised by Box #.
  4548   Wed Apr 20 22:29:07 2011 sureshUpdateRF SystemPlan for LSC rack

The suggested layout of the 1Y2 Rack is shown below.

To simplify the wiring, I have largely kept demod boards with the same same LO frequency close to each other. 

The Heliax cables land on the top and bottom of the of subracks.  These are currently flexible plastic sheets.  Steve has agreed to replace them with something more rigid.  It would be good to have eight N-type connectors on the top and eight  at the bottom.  As  demod boards occur in sets of eight per subrack.  So it would be convenient if the 11 and 55 Mhz Heliax cables land on the top and the rest at the bottom.  In the layout I have shown the current situation. 

The LO signals to the boards come from the RF Distribution box and this is kept in the middle so that cables to both the subracks can be kept short.

The outputs of the AA filter boards from both subracks  have to be connected to the SCSI Interface board with a twisted pair ribbon cable. 

1Y2_Rack_Layout.png

  5002   Wed Jul 20 17:43:33 2011 sureshUpdateComputersrestarted the frame builder

I restarted the frame builder in the last 15mins. 

I was making a change to a DAC channel in the C1IOO model.

  5013   Thu Jul 21 16:05:15 2011 sureshUpdateIOOPSL beam into MC realigned

 I realigned the PSL beam going into the MC.

The MC beam was realigned so as to maximise the power in the MC.  I minimised the MC_RFPD_DCMON dial on the MC_ALIGN screen while adjusting the two zig-zag mirrors at the end of the PSL table.

  6016   Sat Nov 26 07:22:20 2011 sureshUpdateComputers 

c1sus has been shutdown so that the optics dont bang around.  This is because the watch dogs are not working.

  6438   Thu Mar 22 17:41:15 2012 sureshUpdateCDSc1scx and c1scy not properly running

Quote:

It seems that neither c1scx nor c1scy is working properly as their ADC counts are showing digital-zeros.

Quote from #6434

The power was turned back on at 4pm It took some time for Suresh to restart the computers. We have damping but things are not perfect yet. Auto BURTH did not work well.

 When Steve and I restarted the c1iscex and c1iscey computers after the power shutdown, the models within them did not start-up automatically.  I had to start them manually from a terminal in the control room. 

I also tried rebooting the FB a couple of times.  Did not make any difference.

Manually starting the c1x05, c1scy and c1x01, c1scx models (with the Burt Restore button ON) did not resolve the issue of zeros in the epics screens.  though it did re-establish timing. 

  14008   Fri Jun 22 15:22:39 2018 sudoUpdateCDSDTT working
Quote:

Seems like DTT also works now. The trick seems to be to run sudo /usr/bin/diaggui instead of just diaggui. So this is indicative of some conflict between the yum installed gds and the relic gds from our shared drive. I also have to manually change the NDS settings each time, probably there's a way to set all of this up in a more smooth way but I don't know what it is. awggui still doesn't get the correct channels, not sure where I can change the settings to fix that.

DON"T RUN DIAGGUI AS ROOT

ELOG V3.1.3-