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ID Date Author Type Category Subject
9318   Wed Oct 30 08:32:55 2013 EvanHowToComputer Scripts / Programsmatplotlibrc

FYI, you can trick out matplotlib by creating a matplotlibrc config file. This allows you to set defaults for plot size, trace color, fonts, grids, etc., analogous to what is achieved in ATF:1840 for Matlab.

Note also that matplotlib supports LaTeX by default (if you have LaTeX installed), which means, for example, that you can include true square roots on your spectral densities:

plt.ylabel('Voltage spectral density (V/$\\sqrt{\\mathrm{Hz}}$)')

Since the backslash is used for escape characters in python, you must escape LaTeX backslashes.

For maximum effect, you can set the following lines in your matplotlibrc file:

text.usetex = True

text.latex.preamble = \usepackage{txfonts}

Then all text and mathematics in your plot will be sent through LaTeX for processing and will appear in Times.

Also, why is the conversion from watts to volts V = 50 * sqrt(W) and not V = sqrt(50 * W)?

1971   Mon Sep 7 23:51:48 2009 ranaConfigurationComputersmatlab installed: 64-bit linux

I have wiped out the 2008a install of 64-bit linux matlab and installed 2009a in its place. Enjoy.

5019   Fri Jul 22 15:39:55 2011 haixingUpdateSUSmatching the magnets

Yi Xie and Haixing,

We used the Gauss meter to measure the strength distribution of bought magnets, which follows a nice Gaussian distribution.
We pick out four pairs--four fixed magnets and four for the levitated plate that are matched in strength. The force difference is
anticipated to be within 0.2%, and we are going to measure the force as a function of distance to further confirm this.

In the coming week, we will measure various transfer functions in the path from the sensors to the coils (the actuator). The obtained
parameters will be put into our model to determine the control scheme. The model is currently written in mathematica which can
analyze the stability from open-loop transfer function.

1682   Wed Jun 17 01:07:50 2009 robConfigurationComputersmatapps on /cvs/cds

I checked out a copy of matapps into /cvs/cds/caltech/apps/lscsoft so that I could find the matlab function strassign.m, which is necessary for some old mDV commands to run.  I don't know why it became necessary or why it disappeared if it did.

10456   Fri Sep 5 03:36:00 2014 ranaUpdateComputer Scripts / Programsmartian wireless tweak

I changed the Martian wireless router to use channel 10 instead of something random (as it was). Using the Android app 'Wifi Analyzer' we could see that the usual channels are dominated by FlumeLab and Caltech Beaver.

The range from 9-13 looked clean so we put it up there. Also, the signal strength drops from -45 to -70 dBm as we walk from the BS down to the ends. We need to tweak the router position and orientation to give us another 10 dB so that we can reliably run the laptops at the ends.

3627   Thu Sep 30 14:09:33 2010 yutaUpdateComputersmariabella connects to the wireless network

Background:
We need laptops that connect to the wireless network to use them in the lab.

mariabella:
Dell Inspiron 1210 laptop
Broadcom Corporation BCM4312 802.11b/g (rev 01) (PCIID: 14e4:4315 (rev 01))

What I did:
1. I followed the same steps I did for aldabella: http://nodus.ligo.caltech.edu:8080/40m/3623
Except I unzipped R151517-pruned.zip.

2. Note that the PCIID is important for driver selection. Not the model No.
To check whether your driver selection is correct, run:
# ndiswrapper -l
after installing the driver.
If the driver selection is wrong, it will return only:
bcmwl5 : driver installed
If correct, it will return:
bcmwl5 : driver installed          device (14E4:4315) present (alternate driver: hoge)

Result:
aldabella now connects to the wireless martian network.

Note:

Broadcom official driver didn't work for mariabella, too.

1019   Thu Oct 2 02:45:50 2008 robUpdateLockingmarginally better
Locking the DRMI with the +f2 sideband was marginally better tonight. I was able to get it lock stably enough to take transfer
functions and handoff MICH & PRC to double demod signals. After re-alignment, however, behaviour was similar to last night
(locks quickly but only for a few seconds), so that lends some credence to HOM-as-bad-guy theories.
2138   Fri Oct 23 15:02:00 2009 robUpdateloremarconi phase

So, it appears that one doesn't even have to change the Marconi set frequency to alter the phase of the output signal.  It appears that other front panel actions (turning external modulations on/off, changing the modulation type) can do it as well.  At least that's what I conclude from earlier this morning, when after setting up the f2 Marconi (166MHz) for external AM, the double-demod handoff in the DRMI no longer worked.  Luckily this isn't a real problem now that we have the setDDphases and senseDRM scripts.

2139   Sat Oct 24 04:57:33 2009 ranaUpdateloremarconi phase

 Quote: So, it appears that one doesn't even have to change the Marconi set frequency to alter the phase of the output signal.  It appears that other front panel actions (turning external modulations on/off, changing the modulation type) can do it as well.  At least that's what I conclude from earlier this morning, when after setting up the f2 Marconi (166MHz) for external AM, the double-demod handoff in the DRMI no longer worked.  Luckily this isn't a real problem now that we have the setDDphases and senseDRM scripts.

The real problem is that we are using frequency synthesizers to make the beat signals (133 and 199) instead of mixers. Luckily, the future 40m will not use beat signals (?) or synthesizers.

5124   Fri Aug 5 14:03:12 2011 steveUpdateGeneralmalfunctioning crane at ETMY

The horizontal trolley drive stopped working  at the east end this morning. It is working intermittently. In the worst case we can take the door off with the manual -Genie- lift.

I'm working with Konecrane to solve  the wormgear drive problem.

5193   Thu Aug 11 15:31:43 2011 steveUpdateGeneralmalfunctioning crane at ETMY

 Quote: The horizontal trolley drive stopped working  at the east end this morning. It is working intermittently. In the worst case we can take the door off with the manual -Genie- lift. I'm working with Konecrane to solve  the wormgear drive problem.

Gear box found, it's  lead time one week at \$825    The crane may be functional round August 25

14799   Mon Jul 22 21:04:40 2019 ranaUpdateComputersmaking rossa great again
• copied over /etc/fstab lines from pianosa sothat the NFS mounts work correctly
• added symlinks so that the NFS dirs mount in the right dirs
• installed Opera browser
• symlink libsasl2.so.3 -> libsasl2.so.2 and now DTT runs and can get data now and in the past
• DTT can natively produce PDF so you don't have to take screen caps of your camera phone and make a chalk drawing of that anymore
• sitemap/MEDM is working
• after editing fonts.alias as detailed in Thorne wiki, I ran 'sudo xset fp rehash' to get MEDM to notice new fonts. MEDM Scalable fonts are back!!
• installed Grace and now dataviewer works
• ndscope not running: yum install ndscope breaks because it can't find a couple of python34 packages
• tested that AWGGUI also runs and puts in real sine waves
14831   Tue Aug 6 14:12:02 2019 yehonathanUpdateComputersmaking rossa great again

cdsutils is not working on rossa.

Import cdsutils produces this error:

In [2]: import cdsutils
---------------------------------------------------------------------------
OSError                                   Traceback (most recent call last)
<ipython-input-2-949babce8459> in <module>()
----> 1 import cdsutils

/ligo/apps/linux-x86_64/cdsutils-480/lib/python2.7/site-packages/cdsutils/__init__.py in <module>()
53
54 try:
---> 55     import awg
56 except ImportError:
57     pass

/ligo/apps/linux-x86_64/cdsutils-480/lib/python2.7/site-packages/cdsutils/awg.py in <module>()
30 """
31
---> 32 import sys, numpy, awgbase
33 from time import sleep

/ligo/apps/linux-x86_64/cdsutils-480/lib/python2.7/site-packages/cdsutils/awgbase.py in <module>()
17 libawg = CDLL('libawg.so')
18 libtestpoint = CDLL('libtestpoint.so')
---> 19 libSIStr = CDLL('libSIStr.so')
20
21 ####

/ligo/apps/anaconda/lib/python2.7/ctypes/__init__.pyc in __init__(self, name, mode, handle, use_errno, use_last_error)
364
365         if handle is None:
--> 366             self._handle = _dlopen(self._name, mode)
367         else:
368             self._handle = handle

OSError: libSIStr.so: cannot open shared object file: No such file or directory

3785   Tue Oct 26 12:45:20 2010 yutaHowToCDSmaking a new master file for medm screens

(Joe, Yuta)

In elog #3708, we showed how to edit all the similar medm screens easiliy.
But if there are no master files you want to edit in /opt/rtcds/caltech/c1/medm/master/ directory, you can make one.
Say, you want to edit all the similar medm screens named C1SUS_NAME_XXX.adl.

2. Go to that directory and
sed -i 's/NAME/DEFAULTNAME/g' C1SUS_DEFUALTNAME_XXX.adl

5. Run ./generate_master_screens.py

That's all!!

8549   Wed May 8 17:03:35 2013 JamieConfigurationCDSmake direct IPC connections between c1lsc and c1sus/c1mcs

Previously, for some reason, many IPC connections were routed through the c1rfm model, even if a direct IPC connection was possible.  It's unclear why this was done.  I spoke to Joe B. about it and he couldn't remember either.  Best guess is that it was just for book keeping purposes.  Or maybe some old timing issue that has been fixed by DMA fixes in the RTS.  So the point is that it's no longer needed, and we can reduce delays by making direct connections.

I made direct IPC connections from c1lsc to both c1sus and c1mcs, bypassing the c1rfm, through which they had previously been routed.  All models were rebuilt/installed/restarted and everything seems to be working fine.

4493   Wed Apr 6 18:55:49 2011 Jamie, LarisaConfigurationLSCmajor AP table cleanup

We ripped out all of the old AS, PLL, and REFL paths, green, orange, and cyan respectively on the old AP table layout photo:

• AS (green): had already been re-purposed by putting a ThorLabs diode right after the first steering mirror.   Everything downstream of that has been removed.
• PLL (orange): everything removed.
• REFL (cyan): CCD was left in place, so everything upstream of that was not touched.  Everything else was removed, including all of the REFL detectors.
• OMCT (purple): previously removed
• OMCR (blue): left in place, but the diode and CCD are not connected (found that way).
• MCT (magenta): previously removed.
• IMRC (red): untouched

All optics and components were moved to the very south end of the SP table.

We also removed all spurious cables from the table top, and from underneath, as well as pulled out no-longer-needed power supplies.

3549   Thu Sep 9 08:23:45 2010 steveUpdateSAFETYmain laser turned off

Innolight 2W 1064nm main laser was turned off for more enclosure related work.

The electrician re rooting the power- conduit to the interlock under the floor and bring it through the new concrete tunnel.

Emergency laser power shut off switch was tested at entry door 104M.  It worked fine.

No laser glasses required. Laser will be turned back on around 11 am today.

14259   Wed Oct 17 09:31:24 2018 SteveUpdatePSLmain laser off

The main laser went off when PSL doors were opened-closed. It was turned back on and the PSL is locked.

3550   Thu Sep 9 11:17:15 2010 steveUpdateSAFETYmain laser is back ON

 Quote: Innolight 2W 1064nm main laser was turned off for more enclosure related work. The electrician re rooting the power- conduit to the interlock under the floor and bring it through the new concrete tunnel. Emergency laser power shut off switch was tested at entry door 104M.  It worked fine.   No laser glasses required. Laser will be turned back on around 11 am today.

Atm1,   AC power line to enclosure and interlock  was extended.

Atm2,   24V line to interlock rerouted

Atm3,   job is completed

SAFETY GLASSES REQUIRED !  SAFETY GLASSES REQUIRED!

The laser is turned on. Injection current set to 0.871A.

Actually some one turned the  laser  off last night and did  not enter it into the elog ! Burned toast award is granted !

3554   Thu Sep 9 16:54:56 2010 ranaUpdateSAFETYmain laser is back ON

I turned off the laser last night to protect against the electricians. but failed to elog it. I accept the burnt toast completely.

2245   Wed Nov 11 21:30:20 2009 HaixingUpdateGeneralmagnetic levitation modelling files uploaded to svn

I have created a directory under the svn. The link is https://nodus.ligo.caltech.edu:30889/svn/trunk/docs/haixing

In the directory, there are three folders are related to the magnetic levitation.

The experimental data is in the "experiment_data".

The comsol numerical modelling files are in "mag_levi_comsol_modelling" which contains "1x1 magnets",

"4x4 magnets" and "16x16 magnets" sub-folders where detailed modelling results are included.The mathematica

notebooks in those folders are used to produce the plots I posted on the wiki page.

The "mag_levi_feedback" contains the Simulink modelling of the feedback loop. To generate the plot for the

open-loop transfer function. One needs to ruc the "mag_lev.m" file.

1672   Fri Jun 12 15:34:49 2009 steveConfigurationVACmaglev is running

 Quote: Joe and Steve   The retrofitted Osaka 390 was installed on the pumpspool yesterday. V1 gate valve is disabled for safety by disconnected pneumatic power plug. The foreline of this maglev now have a KF25 size viton o-ring directly on the turbo. This is bad for leak hunting. Joe is ready with new interface cable. Power supply and cables are in place. The maglev was pumped down this morning. All new gas kits and metal hose were leak checked by sprayed methanol. There is no obvious sign of leak. I was expecting the pressure to drop below 1e-5 Torr in one hour. TP2 is drying out the levitating coils of the turbo at ~7 l/s for N2 We'll start the pump as soon as Joe is in.

Joe and Steve

The Maglev is running at 680 Hz, 40,800 RPM with V1 gate valve  closed and  valve disabled to change position. C1vac2 was rebooted before starting.

Interlocks are not tested yet, but the medm COVAC_MONITOR.adl screen is reading correctly. RGA scan will determine the need for baking on Monday

The foreline pressure is still  ~2e-5 Torr

Acceleration takes 3 minutes 30sesconds without load. There is no observabale temp effect on the body of the turbo during braking and acceleration.

The IFO is still pumped by the CRYO only

1506   Tue Apr 21 18:18:27 2009 steveUpdateVACmaglev failed

Our Osaka TG360MB maglev failed with CSB error message. This means that the dry emergency landing bearing has to be replaced.

I will consalt with Osaka about the choice of replacing bearing or installing new spare  tomorrow.

Mean while V1 is closed and the vac envelope is not pumped.

Valve configuration: BG -background, pumping on the RGA-only

High voltage to IOO PZT steering mirrors and OMC are turned off.

PSL output shutter is closed and manual block is in place.

I will start cooling the CYO pump in the morning, so the IFO will be pumped by noon.

Outgassing plus leakrate after  10 hrs the pressure is 2.3 mTorr

This rate of rise is normal and it is safe to work with the ifo.

3200   Mon Jul 12 21:26:02 2010 Katharine, SharmilaUpdateelogmaglev coils

The connection between our coil wires and BNC terminals was pretty awful (soldered wires broke off ) so we removed the old heat shrink and re-soldered the wires.  We then chose more appropriately sized heat shrinks (small one around each of the two soldered wires, a medium-sized shrink around the wires together, a large one covering the BNC terminal and the wire) and used the solder iron and heat gun to shrink them.

1594   Sun May 17 20:50:38 2009 robOmnistructureEnvironmentmag 5.0 earthquake in inglewood

## 2009 May 18 03:39:36 UTC

### Earthquake Details

Magnitude 5.0 Monday, May 18, 2009 at 03:39:36 UTC Sunday, May 17, 2009 at 08:39:36 PM at epicenter 33.940°N, 118.338°W 13.5 km (8.4 miles) GREATER LOS ANGELES AREA, CALIFORNIA 2 km (1 miles) E (91°) from Lennox, CA 2 km (1 miles) SSE (159°) from Inglewood, CA 3 km (2 miles) NNE (22°) from Hawthorne, CA 7 km (4 miles) ENE (72°) from El Segundo, CA 15 km (10 miles) SSW (213°) from Los Angeles Civic Center, CA horizontal +/- 0.4 km (0.2 miles); depth +/- 0.9 km (0.6 miles) Nph=139, Dmin=7 km, Rmss=0.42 sec, Gp= 40°, M-type=local magnitude (ML), Version=C California Integrated Seismic Net: USGS Caltech CGS UCB UCSD UNR ci10410337
784   Sat Aug 2 16:05:38 2008 ranaConfigurationComputer Scripts / ProgramsmDV update
I did an svn update on our mDV directory. Justin has improved it so that the NDS client binaries
are included for solaris, mac, linux32, and linux64. Now you can just use this version without
having to worry about any path definitions.
631   Thu Jul 3 13:54:26 2008 robConfigurationComputersmDV on rosalba

Does mDV work on rosalba? It can't find NDS_GetChannels. Looking on mafalda, I see that NDS_GetChannels is a mexglx. I think this means someone may need to compile it for 64-bit matlab before we can have mDV on rosalba. When that's done, we should get mDV running on megatron.
270   Fri Jan 25 21:36:40 2008 ranaUpdateCDSmDV / channel issues
Fri Jan 25 21:30:00 2008

As it turns out, the residual problem with the mDV stuff was not to do with our button pushing episode but instead fallout from the 'turning off of the computers' during the water leak caused by the rain and construction.

The /frames partition from fb0 (the FrameBuilder) is not mounted to the control machines via vfstab; it does not remount on bootup. I originally did this because Ben Johnson and Dave Barker had warned me that during a power outage, fb0 may not come up right away. This could make the control room machines hang up for awhile. I elected to have the mount be by hand.

So the thing to do is to put the mount command into the cold start procedures (Andrey). Its in an old elog entry of mine from Feb '07.
5008   Wed Jul 20 22:16:27 2011 Ishwita, ManuelUpdateElectronicslying seismometer cable and plugging it

We laid the cable along the cable keeper from the BACARDI seismometer to the rack 1X6, the excess cable has been coiled under the X arm.

We plugged the cable to the seismometer and to the seismometer electronics box in rack 1X6. We also plugged the AC power cable from the box to an outlet in rack 1X7 (because the 1X6 outlets are full)

With the help of a function generator we tested the following labeled channels of AA board...

2, 3, 11, 12, 14, 15, 16, 18, 19, 20 and 24

that are the channels that can be viewed by the dataviewer, also the channel 10 can be viewed but it's labeld BAD so we cannot use it.

We leveled the seismometer and unlocked it, and saw his X,Y,Z velocity signals with an oscilloscope.

6332   Tue Feb 28 16:12:59 2012 DenUpdateAdaptive Filteringlunch talk

Just to be clear what I said at the meeting, I write all this down here. Adaptive filtering of real signals (MC_F and GUR1_X) with all noises inside is

This is offline filtering but with real signals and with the C-code that is compiled at the 40m now. We can reduce the MC_F signal by ~100 below 10 Hz, but  the problem is that reducing the adaptation gain, the error increases. As a result when we move towards FxLMS algorithm with AA, AI and downsampling, we have to take the gain equal to ~1e-2 and we do not reduce any noise.

The second demonstration of this problem is static Wiener filtering. This is the result

We can see that adaptive filtering outperforms the "optimal" filtering. This is because an adaptive filter can follow the changes of coefficients immediately while the Wiener filter averages them. This is the mathematical formulation:

mcl_real = coeff _real* seismic_noise_real + other_noise

mcl_real - the real length of the MC,

coeff_real - real coefficients, that represent the transfer function between seismic noise and MC length,

other_noise - noise uncorrelated to the seismic noise seismic_noise_real

But in the world of our measured signals we have the equation

mcl_measured = coeff * seismic_noise_measured + other_noise

mcl_measured = TF_mcl * mcl_real

seismic_noise_measured = TF_seis * seismic_noise_real

where TF_mcl and TF_seis - transfer functions from the real world to measurements.

It seems to me that TF_mcl or TF_seis are not constants and for that reason the TF between measured seismic noise and mcl is not constant. But it is exactly what an adaptive or Wiener filter tries to define:

coeff(time) = average(coeff(time)) + delta(coeff(time))

The result of applying average(coeff) is the green line in the Figure 2 - error after applying the Wiener filtering.

delta(coeff) - the changing part of the transfer function is caught by the adaptive filtering. The lower the gain, the lower is the capability of adaptive filter to catch these changes. Theoretically. the error after applying adaptive filter can be presented like this:

E(error*error) = E(other_noises*other_noises) + 1/(2-mu)*mu*E(other_noises*other_noises)  + 1/ {mu*(2-mu)} * Tr(Q) * A

Q - covariance matrix of delta(coeff)

A - norm of the seismic signal

The first term in this equation is the dispersion of other noises, the second term is the error of the adaptive filter due to non-zero gain, the third term is due to the changes in the transfer function - we can see that it is proportional to 1/mu. This term explains why the error increases while mu decreases.

Now I'm looking for the part in the path of the signals where the transfer function can change. As I mentioned above, this is not a change in the real world, it is the change in the measured signlals. My first guess is the quantization error - we do not have not enough counts. If this is not the case, I'll move to other things of the signal path.

2877   Tue May 4 13:14:43 2010 josephbUpdateCDSlsc.mdl and ifo.mdl to build (with caveats)

I got around to actually try building the LSC and IFO models on megatron.  Turns out "ifo" can't be used as a model name and breaks when trying to build it.  Has something to do with the find and replace routines I have a feeling (ifo is used for the C1, H1, etc type replacements throughout the code).  If you change the model name to something like ifa, it builds fine though.  This does mean we need a new name for the ifo model.

Also learned the model likes to have the cdsIPCx memory locations terminated on the inputs if its being used in a input role (I.e. its bringing the channel into the model).  However when the same part is being used in an output role (i.e. its transmitting from the model to some other model), if you terminate the output side, it gives errors when you try to make.

Its using the C1.ipc file (in /cvs/cds/caltech/chans/ipc/) just fine.  If you have missing memory locations in the C1.ipc file (i.e. you forgot to define something) it gives a readable error message at compile time, which is good.  The file seems to be being parsed properly, so the era of writing "0x20fc" for block names is officially over.

2885   Thu May 6 11:34:35 2010 robUpdateCDSlsc.mdl and ifo.mdl to build (with caveats)

 Quote: I got around to actually try building the LSC and IFO models on megatron.  Turns out "ifo" can't be used as a model name and breaks when trying to build it.  Has something to do with the find and replace routines I have a feeling (ifo is used for the C1, H1, etc type replacements throughout the code).  If you change the model name to something like ifa, it builds fine though.  This does mean we need a new name for the ifo model. Also learned the model likes to have the cdsIPCx memory locations terminated on the inputs if its being used in a input role (I.e. its bringing the channel into the model).  However when the same part is being used in an output role (i.e. its transmitting from the model to some other model), if you terminate the output side, it gives errors when you try to make. Its using the C1.ipc file (in /cvs/cds/caltech/chans/ipc/) just fine.  If you have missing memory locations in the C1.ipc file (i.e. you forgot to define something) it gives a readable error message at compile time, which is good.  The file seems to be being parsed properly, so the era of writing "0x20fc" for block names is officially over.

I suggest "ITF" for the model name.

6750   Mon Jun 4 23:48:43 2012 jenneUpdateGreen Lockinglowered gain

We're trying to do a yarm measurement....before I forget, I want to write this down...

I changed the gain of each of the top 2 SR560's down, by a factor of 2.  This made the overload lights quit coming on.

9580   Tue Jan 28 09:51:47 2014 SteveUpdateIOOlow power pointing

PSL output is stable.

10112   Mon Jun 30 10:06:39 2014 SteveUpdateVAClow on pneumatic pressure of vacuum valves

This morning valve condition: V1, VM1, V4 and V5 valves were closed. IFO pressure rose to 1.3 mTorr

It was caused by low N2 pressure.  Our vacuum valves are moved-controlled by 60-70 PSI of nitrogen.

When this supply drops below 50-60 PSI the interlock closes V1 valve. This is the minimum pressure required to move the large valves.

It is our responsibility to check the N2 cylinder pressure supply.

The vacuum valve configuration is back to VAC. NORMAL,  CC1  4.8E-6 Torr

PS: Bob says that the second cylinder was full this morning, but the auto-switch over did not happen.

962   Thu Sep 18 09:30:12 2008 steveUpdateGenerallow noise metal film resistors are in
Low noise metal film resistor and capacitor kits from www.garrettelec.com are in.

manufacturer: Dale, 289 values, 25ea, surface mount,1206, 0.1% from 100 to 100K, 1/8 or 1/4W
additional values below 100 ohm and above 100K were purchased from Mouser with the same Dale specification

Ceramic capacitor kit from AVX
67 values, 25ea, surface mount, 1206 from 1.0 pF up

atm2: our new storage cabinet pick and put together by Jenni
9473   Sat Dec 14 13:46:54 2013 DenUpdateIOOlow bandwidth MCL loop

Last time we designed MCL loop with UGF ~ 30 Hz and I think, it was hard to lock the arm because of large frequency noise injected to IFO.

This time I made a low bandwidth MCL loop with UGF=8 Hz. MCL error RMS is suppressed by factor of 10 and arms lock fine.

Attached plots show MCL OL, MCL error suppression and frequency noise injection to arms.

It is interesting that spectrum of arms increases below 1 Hz meaning that IMC sensing noise dominates in this range.

I did not include the loop into the IMC autolocker. I think it is necessary to turn it on only during day time activity and when beatnote is moving too much during arm stabilization.

8083   Thu Feb 14 08:29:41 2013 SteveUpdateIOOlow MC1 OSEM voltage

MC1 -  LR, LL, UL & UR  OSEMs should be adjusted to get  1.2V

8107   Tue Feb 19 09:37:23 2013 SteveUpdateIOOlow MC1 OSEM voltage

See TT DB25 pin swapping   elog#7869

239   Tue Jan 15 13:15:27 2008 tobinUpdateEnvironmentlots of noise
They're throwing concrete around at the construction site.
13307   Mon Sep 11 12:56:40 2017 johannesUpdateComputer Scripts / Programslossmap attempts

I was trying to get a lossmap measurement over the weekend but had some trouble first with the IMC and then with the PMC.

For the IMC: It was a bit too misaligned to catch and maintain lock, but I had a hard time improving the alignment by hand. Fortunately, turning on the WFS quickly once it was locked restored the transmission to nominal levels and made it maintain the lock for longer, but only for several minutes, not enough for a lossmap scan (can take up to an hour). Using the WFS information I manually realigned the IMC, which made locking easier but wouldn't help with staying locked.

For the PMC: The PZT feedback signal had railed and the PMC had been unlocked for 8+ hours. The PMC medm screen controls were generally responsive (I could see the modes on the CCDs changing) but I just couldn't get it locked. c1psl was responding to ping but refusing telnet so I keyed the crate, followed by a burt restore and finally it worked.

After the PMC came back the IMC has already maintained lock for more than an hour, so I'm now running the first lossmap measurements.

12874   Wed Mar 8 18:18:51 2017 johannesUpdateComputer Scripts / Programsloss script

I started a loss script on Donatella that will scan the beam spot across ETMY, recording the reflected power from the arm via the networked scope at the AS port until later tonight (should be done by 9 pm). ITMX is currently strongly misaligned for this, but can be restored with the saved values. I mostly adapted the mapping scipts for the scope readout but still have to iron out a few kinks, which is why I'm running this test. In particular, I still need to calibrate how much the spot actually moves on the optic and control the ASS demodulation offsets to keep the beam stationary on ITMY.

12879   Thu Mar 9 22:28:11 2017 johannesUpdateComputer Scripts / Programsloss script

loss map script running on Rossa that moves the beam on ETMX. Yarm was misaligned for this, most recent PIT and YAW settings were saved beforehand. This will take until late at night, I estimate 2-3 am.

 Quote: I started a loss script on Donatella that will scan the beam spot across ETMY, recording the reflected power from the arm via the networked scope at the AS port until later tonight (should be done by 9 pm). ITMX is currently strongly misaligned for this, but can be restored with the saved values. I mostly adapted the mapping scipts for the scope readout but still have to iron out a few kinks, which is why I'm running this test. In particular, I still need to calibrate how much the spot actually moves on the optic and control the ASS demodulation offsets to keep the beam stationary on ITMY.

12880   Fri Mar 10 11:37:25 2017 gautamUpdateComputer Scripts / Programsloss script

This was still running at ~9.30am today morning, at which point I manually terminated it after confirming with Johannes that it was okay to do so. Judging by the StripTool traces in the control room, the mode cleaner remained locked for most of the night, there should be plenty of usable data...

Note that I re-aligned the Y-arm (to experiment further with photo-taking) at about 9.30am, so the data after this time should be disregarded...

 Quote: loss map script running on Rossa that moves the beam on ETMX. Yarm was misaligned for this, most recent PIT and YAW settings were saved beforehand. This will take until late at night, I estimate 2-3 am.

12882   Fri Mar 10 19:48:56 2017 johannesUpdateComputer Scripts / Programsloss script

Loss script running again, on Pianosa this time. Due to an oversight in the code the beam wasn't actually moved across ETMY last night. This time I confirmed that the correct offset value is written as a demodulation parameter to the correct mirror degree of freedom. Script will probably run through the night. Yarm is currently misaligned but previous alignment was saved.

12883   Sat Mar 11 20:11:58 2017 johannesUpdateComputer Scripts / Programsloss script

Yarm script running on Pianosa. Still working on visualization of the ETMX lossmap.

 Quote: Loss script running again, on Pianosa this time. Due to an oversight in the code the beam wasn't actually moved across ETMY last night. This time I confirmed that the correct offset value is written as a demodulation parameter to the correct mirror degree of freedom. Script will probably run through the night. Yarm is currently misaligned but previous alignment was saved.

35   Wed Oct 31 08:34:35 2007 ranaOtherIOOloss measurements
In the end, we were unable to get a good scatter measurement just because we ran out of steam. The idea was to get a frame
grab image of MC2 but that involves getting an unsaturated image.

In the end we settle for the ringdowns, Rob's (so far unlogged) cavity pole measurement, and the MC transmission numbers. They
all point to ~100-150 ppm scatter loss per mirror. We'll see what happens after wiping.
14243   Thu Oct 11 13:40:51 2018 yukiUpdateComputer Scripts / Programsloss measurements
 Quote: This is the procedure I follow when I take these measurements for the XARM (symmetric under XARM <-> YARM): Dither-align the interferometer with both arms locked. Freeze outputs when done. Misalign ETMY + ITMY. ITMY needs to be misaligned further. Moving the slider by at least +0.2 is plentiful to not have the other beam interfere with the measurement. Start the script, which does the following: Resume dithering of the XARM Check XARM dither error signal rms with CDS. If they're calm enough, proceed. Freeze dithering Start a new set of averages on the scope, wait T_WAIT (5 seconds) Read data (= ASDC power and MC2 trans) from scope and save Misalign ETMX and wait 5s Read data from scope and save Repeat desired amount of times Close the PSL shutter and measure the PD dark levels

Information for the armloss measurement:

• Script which gets the data:  /users/johannes/40m/armloss/scripts/armloss_scope/armloss_dcrefl_asdcpd_scope.py
• Script which calculates the loss: /users/johannes/40m/armloss/scripts/misc/armloss_AS_calc.py
• Before doing the procedure Johannes wrote you have to prepare as follows:
• put a PD in anti-symmetric beam path to get ASDC signal.
• put a PD in MC2 box to get tranmitted light of IMC. It is used to normalize the beam power.
• connect those 2 PDs to oscilloscope and insert an internet cable to it.
• Usage: python2 armloss_dcrefl_asdcpd_scope.py [IP address of Scope] [ScopeCH for AS] [ScopeCH for MC] [Num of iteration] [ArmMode]

Note: The scripts uses httplib2 module. You have to install it if you don't have.

The locked arms are needed to calculate armloss but the alignment of PMC is deadly bad now. So at first I will make it aligned. (Gautam aligned it and PMC is locked now.)

gautam: The PMC alignment was fine, the problem was that the c1psl slow machine had become unresponsive, which prevented the PMC length servo from functioning correctly. I rebooted the machine and undid the alignment changes Yuki had made on the PSL table.

14245   Fri Oct 12 12:29:34 2018 yukiUpdateComputer Scripts / Programsloss measurements

With Gautam's help, Y-arm was locked. Then I ran the script "armloss_dcrefl_asdcpd_scope.py" which gets the signals from oscilloscope. It ran and got data, but I found some problems.

1. It seemed that a process which makes arm cavity mislaigned in the script didn't work.
2. The script "armloss_dcrefl_asdcpd_scope.py" gets the signal and the another script "armloss_AS_calc.py" calculates the arm loss. But output file the former makes doesn't match with the type the latter requires. A script converts format is needed.

Anyway, I got the data needed so I will calculate the loss after converting the format.

14248   Fri Oct 12 20:20:29 2018 yukiUpdateComputer Scripts / Programsloss measurements

I ran the script for measuring arm-loss and calculated rough Y-arm round trip loss temporally. The result was 89.6ppm. (The error should be considered later.)

The measurement was done as follows:

1. install hardware
1. Put a PD (PDA520) in anti-symmetric beam path to get ASDC signal.
2. Use a PD (PDA255) in MC2 box to get tranmitted light of IMC. It is used to normalize the beam power.
3. Connect those 2 PDs to oscilloscope (IP: 192.168.113.25) and insert an internet cable to it.
2. measure DARK noise
1. Block beam going into PDs with dampers and turn off the room light.
2. Run the script "armloss_dcrefl_acdcpd_scope.py" using "DARK" mode.
3. measure the ASDC power when Y-arm locked and misaligned
1. Remove dampers and turn off the room light.
2. Dither-align the interferometer with both arms locked. Freeze outputs when done. (Click C1ASS.adl>!MoreScripts>ON and click C1ASS.adl>!MoreScripts>FreezeOutputs.)
3. Misalign ETMX + ITMX. (Just click "Misalign" button.)
4. Further misalign ITMX with the slider. (see previous study: ITMX needs to be misaligned further. Moving the slider by at least +0.2 is plentiful to not have the other beam interfere with the measurement.)
5. Start the script "armloss_dcrefl_acdcpd_scope.py" using "ETMY" mode, which does the following:
1. Resume dithering of the YARM.
2. Check YARM dither error signal rms with CDS. If they're calm enough, proceed. (In the previous study the rms threshold was 0.7. Now "ETM_YAW_L_DEMOD_I" signal was 15 (noisy), then the threshold was set 17.)
3. Freeze dithering.
4. Start a new set of averages on the scope, wait T_WAIT (5 seconds).
5. Read data (= ASDC power and MC2 trans) from scope and save.
6. Misalign ETMY and wait 5s. (I added a code which switchs LSC mode ON and OFF.)
7. Read data from scope and save.
8. Repeat desired amount of times.
4. calculate the arm loss
1. Start the script "armloss_AS_calc.py", whose content is follows:
• requires given parameters: Mode-Matching effeciency, modulation depth, transmissivity. I used the same value as Johannes did last year, which are (huga)
• reads datafile of beam power at ASDC and MC2 trans, which file is created by "armloss_dcrefl_acdcpd_scope.py".
• calculates arm loss from the equation (see 12528 and 12854).

Result:

YARM
('AS_DARK =', '0.0019517200000000003') #dark noise at ASDC
('MC_DARK =', '0.02792') #dark noise at MC2 trans
('AS_LOCKED =', '2.04293') #beam power at ASDC when the cavity was locked
('MC_LOCKED =', '2.6951620000000003')
('AS_MISALIGNED =', '2.0445439999999997') #beam power at ASDC when the cavity was misaligned
('MC_MISALIGNED =', '2.665312')

$\hat{P} = \frac{P_{AS}-P_{AS}^{DARK}}{P_{MC}-P_{MC}^{DARK}}$ #normalized beam power

$\hat{P}^{LOCKED}=0.765,\ \hat{P}^{MISALIGNED}=0.775,\ \mathcal{L}=89.6\ \mathrm{ppm}$

• My first (wrong) measurement said the arm loss was negative(!). That was caused by lack of enough misalignment of another arm mirrors. If you don't misalign ITMX enough then the beam or scattered light from X-arm would bring bad. The calculated negative loss would be appeared only when $\frac{\hat{P}^{LOCKED}}{\hat{P}^{MISALIGNED}} > 1 + T_{ITM}$