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ID Date Author Type Category Subject
  6550   Thu Apr 19 16:21:04 2012 ZachUpdateComputer Scripts / ProgramsArbcav updated, made badass

I have modified Arbcav to be way cooler than it used to be.

Main modifications:

  • Can now truly model an arbitrary cavity geometry
    • The previous version could only handle a few different topologies. In each case, it would unfold the cavity into the equivalent linear cavity and use the g-parameter method to calculate gouy phases, etc.
    • The new model uses the closed cavity propagation matrix to find the supported mode, and then explicitly calculates the accumulated gouy phase by propagating the beam through the full cavity. This is done analytically with zR, so there is negligible slow-down.
  • Now plots a diagram of the cavity geometry, both to help you and for you to verify that it is calculating the right thing (<-- this is the cool part)
    • Plots the beam path and mirror locations
    • Specifies whether mirrors are curved or flat
    • Prints mirror parameters next to them
    • Finds all intracavity waist locations and plots them
    • Gives waist information (size in X, Y)

Since the information is already there, I will have the output structure include things like the input beam q parameter, which could then be fed directly to mode matching tools like ModeMatchr.

The function takes as input the same arguments as before. Example for a square cavity:

out = arbcav([200e-6 50e-6 200e-6 50e-6],[0.75 0.75 0.75 0.75],[1e10 9 1e10 9],[45 45 45 45],29.189e6,10e-6,1064e-9,1000);

i.e.,

out = arbcav(transmissivity_list, length_list, RoC_list, angle_list, modulation_freq, loss_list_or_loss_per_mirror, wavelength, num_pts_for_plot);

If you don't give it a modulation frequency, it will just plot carrier HOMs. If you don't give it RoCs and angles, it will just plot the transmission spectrum.

 

I'm still fine-tuning some functionality, but I should have it up on the SVN relatively soon. Comments or suggestions are welcome!

 

Some screenshots:

Cavity geometry plots (linear, triangular, square, bowtie):

linear.pngtriangular.pnggyro.pngbowtie.png

 

Transmission and HOM spectra (these correspond to the square cavity at lower left, above):

gyro_spect.pnggyro_HOM.png

  6549   Thu Apr 19 09:45:43 2012 SureshUpdateGeneralMC2 Oplev signals redirected for use in WFS servo

Quote:

 
Quote:
  • there are no oplev signals in MC1, MC2, and MC3

 None of the 3 MC optics have oplevs, so there shouldn't be any oplev signals. Although MC2 has the trans QPD, which was once (still is??) going through the MC2 oplev signal path.

.......

 

The MC2 Oplev signal path has been modified in the c1mcs model.  The ADC channels have been sent over the rfm into c1ioo model and are currently used in the WFS servo loops.  Please see this elog 5397.

 

  6548   Thu Apr 19 08:43:16 2012 JamieUpdateCDSoaf

Quote:

Edit: Old version (~september) of the code and oaf model is running now. In the 2.1 code there was a link from src/epics/simLink to oaf code for each DOF. It seems that 2.5 version finds models and c codes in standard directories. I need to move working code to the proper directory.

 Yes, things have changed.  Please wait until I have things cleaned up before working on models.  I'll explain what the new setup is.

  6547   Wed Apr 18 23:12:49 2012 DenUpdateCDSoaf

Adaptive filter outputs some non-zero signal in the OFF position

Screenshot.png

I turned "ON" one of them and c1lsc suspended, I've rebooted it and restarted models on c1lsc and c1sus.

Now it also outputs something non-zero though the first line of the adaptive code is "if(OFF) output=0.0; return;" May be another version of the code has been compiled.

Edit: Old version (~september) of the code and oaf model is running now. In the 2.1 code there was a link from src/epics/simLink to oaf code for each DOF. It seems that 2.5 version finds models and c codes in standard directories. I need to move working code to the proper directory.

  6546   Wed Apr 18 19:59:48 2012 JamieUpdateCDSCDS upgrade success

The upgrade is nearly complete:

  • new daqd code is running on fb
  • the fe/daqd timing issue was resolved by adjusting the GPS offset in the daqdrc.  I will document this more later.
  • the power outage conveniently rebooted all the front-end machines, so they're all now running new caRepeater
  • all models have been successfully recompiled with RCG 2.5 (with only a couple small glitches)
  • all new models are running on all front-end machines (with a couple exceptions)
  • all suspension models seem to be damping under local control (PRM is having troubles that are likely unrelated to the upgrade).
  • a lot of cleanup has been done

Remaining tasks/issues:

  • more testing OF EVERYTHING needs o be done
  • I did not yet update the DIS dolphin code, so we're running with the old code.  I don't think this is a problem, but it would be nice to get us running what they're running at the sites
  • I tried to cleanup/simplify how front-end initialization is done.  However, there is a problem and models are not auto-starting after reboot.  This needs to be fixed.
  • the userapps directory is in a new place (/opt/rtcds/userapps).  Not everything in the old location was checked into the repository, so we need to check to make sure everything that needs to be is checked in, and that all the models are running the right code.
  • the c1oaf model seems to be having a dolphin issue that needs to be sorted
  • the c1gfd model causes c1ioo to crash immediately upon being loaded.  I have removed it from the rtsystab.  That model needs to be fixed.
  • general model cleanup is in order.
  • more front-end cleanup is needed, particularly in regards to boot-up procedure.
  • document the entire upgrade procedure.

I'll finish up these remaining tasks tomorrow.

  6545   Wed Apr 18 11:54:31 2012 JenneUpdateGeneralPower outage last night

Quote:

None of the 3 MC optics have oplevs, so there shouldn't be any oplev signals. Although MC2 has the trans QPD, which was once (still is??) going through the MC2 oplev signal path.

 Duh.  Unawake brain.  The MCs look fine.

  6544   Wed Apr 18 11:46:14 2012 JenneUpdateGeneralPower outage last night

Quote:

  • there are no oplev signals in MC1, MC2, and MC3
  • Something is wrong with PRM.  He is very noisy.  Turning on his oplev servo makes him go crazy.

 None of the 3 MC optics have oplevs, so there shouldn't be any oplev signals. Although MC2 has the trans QPD, which was once (still is??) going through the MC2 oplev signal path.

PRM was noisy last week too.  But turning on his oplev shouldn't make him crazy. That's not so good. Try restoring PRM (the ! near the PRM label on the IFO align screen), then checking if his oplev is ~centered.  Maybe PRM wasn't in the nominal position at the time you restored from.

  6543   Wed Apr 18 10:05:40 2012 JamieUpdateGeneralPower outage last night

All of the front-ends are back up and I've been able to recover local control of all of the opitcs (snapshots from saturday). Issues:

  • I can't lock the PMC.  Still unclear why.
  • there are no oplev signals in MC1, MC2, and MC3
  • Something is wrong with PRM.  He is very noisy.  Turning on his oplev servo makes him go crazy.
  • There are all sorts of problems with the oplevs in general.  Many of the optics have no oplev settings.  This is probably not related to the power outage.

On a brighter note, ETMX is damped with it's new RCG 2.5 controller!  yay!

  6542   Wed Apr 18 08:53:50 2012 JamieUpdateGeneralPower outage last night

Apparently there was a catastrophic power failure last night.  Bob says it took out power in most of Pasadena.

Bob checked the vacuum system when he got in first thing this morning and everything's back up and checks out.  The laster is still off and most of the front-end computers did not recover.

I'm going to start a boot fest now.  I'll be able to report more once everything is back on.

  6541   Tue Apr 17 19:03:09 2012 JamieUpdateCDSCDS upgrade in progress

Upgrade progresses, but not complete.  There are some relatively minor issues, and one potentially big issue.

All new software has been installed, including the new epics that supports long channel names.

I've been doing a LOT of cleanup.  It was REALLY messy in there.

The new framebuilder/daqd code is running on fb.

Models are compiling with the new RCG and I am able to get them running.  Some of them are not compiling for relatively minor reasons (the simulink models need updating).  I'm also running into compile problems with IOPs that are using the dolphin drivers.

The major issue is that the framebuilder and the models are not syncing their timing, so there's no data collection.  I've spoken to Alex and he and Rolf are going to come over tomorrow to sort it out.  It's possible that we're missing timing hardware that the new code is expecting.

There are still some stability issues I haven't sorted out yet, and I have a lot more cleanup to do.

At this rate I'm going to shoot for being done Thursday.

  6540   Tue Apr 17 11:05:04 2012 JamieUpdateCDSCDS upgrade in progress

I am continuing to attempt to upgrade the CDS system to RTS 2.5.  Systems will continue to be up and down for the rest of the day.

  6539   Tue Apr 17 10:55:50 2012 RyanUpdateComputersUpdating aLIGO Conlog

Quote:

Over the next few days, I will be working on upgrading the aLIGO Conlog install to include new bugfixes distributed by Patrick T.  The currently running conlog *should* not be affected, but please let me know if it is (ryan.fisher@ligo.org).

 The upgrade to the aLIGO Conlog is completed.  The conlog is once again running on megatron in a screen session. (see http://nodus.ligo.caltech.edu:8080/40m/6396)

  6538   Mon Apr 16 14:37:01 2012 DenUpdatePEMgur2_x

Quote:

Quote:

Already not for the first time I notice that GUR2 readjusts its X zero position

As a result the coherence between GUR1X and GUR2X is lost, but between GUR2X and GUR2Y shows up. It seems that these two signals mix at some point.

 Can you go back in time before the X-position jumped to plot the x1-x2 and x2-y2 coherences?  Just to see what things look like?

DAQ is not working now but ordinary the coherence between GUR1X and GUR2X is ~1 at 0.1 - 10 Hz and between GUR2X and GUR2Y is ~0.

  6537   Mon Apr 16 09:44:54 2012 JenneUpdatePEMgur2_x

Quote:

Already not for the first time I notice that GUR2 readjusts its X zero position

As a result the coherence between GUR1X and GUR2X is lost, but between GUR2X and GUR2Y shows up. It seems that these two signals mix at some point.

 Can you go back in time before the X-position jumped to plot the x1-x2 and x2-y2 coherences?  Just to see what things look like?

  6536   Mon Apr 16 09:10:37 2012 DenUpdatePEMgur2_x

Already not for the first time I notice that GUR2 readjusts its X zero position

seisms.png

 

As a result the coherence between GUR1X and GUR2X is lost, but between GUR2X and GUR2Y shows up. It seems that these two signals mix at some point.

gur12_coh.jpg

  6535   Sat Apr 14 00:19:35 2012 SureshOmnistructureLSCOptical Fibers for insitu RFPD characterisation

   I have worked out the fibers we need to get for the following distribution scheme:

1) We have a laser placed at the 1Y1 rack.  A part of the power is split off for monitoring the laser output and sent to a broadband PD also placed in the same rack.  The RF excitation applied to the laser is split and sent to LSC rack (1Y2) and used to calibrate the full PD+Demod board system for each RFPD.

2) A single fiber goes from the laser to a 11+ way switch located in the OMC electronics cabinet next to the AP table.  From here the fibers branch out to three different tables.

Table / Rack   RF PDs on the table Number of PDs Fiber Length from OMC
The AP table AS11,AS55,AS165,REFL11,REFL33,REFL55,REFL165 7 6 m
The ITMY table POY11 1 12 m
The ITMX table POX11, POP22/110 and POP55 3 20 m

 

Cable for the laser source to the OMC table:

The 1Y1 Rack to OMC rack AM Laser Source to Switch 25 m

We also require a cable going from PSL table to the ETMY table:   This is not a part of the RFPD characterisation.  It is a part of the PSL to Y-end Aux laser lock  which is a part of the green locking scheme.  But it is  fiber we need and might as well order it now along with the rest.

PSL Table to ETMY Table PSL to ETMY Aux laser 75m

 

If you would like to add anything to this layout / scheme, please comment.  On Monday Eric is going to take a look at this and place orders for the fibers.

(I have included the lengths required for routing the fibers and added another 20% to that ) 

 

  6534   Fri Apr 13 16:09:43 2012 SureshUpdateComputer Scripts / ProgramsACAD 2002 installed on C21530

I have installed ACAD 2002 on one of the Windows machines in the Control Room.    It is on the machine which has Solid Works (called C21530). 

The installation files are in MyDocuments under Acad2002.  This a shared LIGO license which Christian Cepada had with him.

I hope we will be able to open our optical layout diagrams with this and update them even though it is an old version.

 

 

  6533   Fri Apr 13 01:27:10 2012 JenneUpdateSUSOplevs recentered

It's been a while since I think anyone has done it, and several optics were pretty far from centered, so I centered all of the oplevs except for SRM.

I am confident about my arm alignment, MICH and PRC (so BS, ITMX, ITMY, PRM, ETMX and ETMY), but I wasn't sure if I was getting SRC right, so I didn't touch the SRM's oplev.

Suresh removed all of the IPPOS measurement optics, so there was nothing blocking the BS and PRM oplevs.

However, the PRM oplev was ridiculously bad, and I don't know how long it's been that way.  Some of the optics shooting the beam into the chamber weren't optimally aligned, so the beam coming out of the chamber was hitting the lowest edge of the optic mount, for the first optic the beam encountered.  I adjusted the mirror launching the beam into the chamber by a teeny bit, so that the outcoming beam was ~horizontal and hitting the center of the first steering mirror in pitch.  I had to move that steering mirror a little to the right (if you are staring at the HR face of the mirror), to get the beam to come close to the horizontal center of the optic.  Then I proceeded to do normal oplev alignment.

Also, I've noticed lately that ITMX is noisier than all the other optics.  It's kind of annoying.  The sensor RMS values reported for the ITMX watchdogs for UL and LL are rarely below 2, and are often (~70% of the time?) above 3.  The SD RMS is a normal 1-ish.

  6532   Thu Apr 12 23:52:49 2012 JenneUpdateLockingPRMI locked - 'bouncy'

I am locking some things, and have the PRM aligned, and it will stay locked for short periods of time, but as Kiwamu warned me, when the PRM alignment is better, the lock is more "crazy" and unstable.  This should go on our list of mysteries.

 

  6531   Thu Apr 12 23:12:16 2012 SureshUpdateIOOBeam Profile measurement: IPPOS beam: Possible Clipping

WiQuote:

[Suresh, Jenne]

  The input beam is most probably being clipped at the Faraday Isolator.  

Evidence: 

.....

We plan to investigate this further to be sure.. 

.....

 

I tried to determine an optimal WFS2YAW offset to be used so that we may avoid clipping.

Initially, I just measured the beam diameter as a function of offset.  If the beam diameter would become independent of offset if it is not clipped.  However a systematic effect became apparent when I shifted the beam on the detector to a slightly different location.  So I repeated the measurements while recentering the beam to the same location everytime  (centered at -1650+/- 50 for both H and V directions).

I have attached plots of the scans for both cases, with recentering and without.    I have not been able to figure out what is going on since the beam diameter does not become independent of the offset.  While the beam profile becomes more gaussian beyond offsets of about 7 or so, the beam diameter does not seem to follow a clear pattern.  The measurements are repeatable (within one sigma) so the experimental errors are smaller than 1 sigma.

The photographs below show the improvement of Horizontal beam profile with WFS2Yaw offset.  These seem to indicate a good gaussian beam for offsets beyond 7 or so.  At offsets more than 12 the MC unlocks.

 

Hor_OSet-2.png Hor_OSet0.png Hor_OSet2.png Hor_OSet8.png
 Offset = -2   Offset = 0   Offset = 2   Offset = 8

 

 

HorizontalNoRecenter.png  HorizontalRecentered.png
  This seems to indicate that the beam diameter does not vary for WFS2Yaw offset > 8  But if we recenter the beam for each measurement this effect seems to vanish

        

 Will continue tomorrow.   Jenne wants to do some IFO locking now.

 

  6530   Thu Apr 12 22:04:17 2012 Mike J.UpdateComputersNew Hysteresis Model & Plots

The new hysteresis model uses a triangle wave with offset zero points as the position function and a sinusoidal force function, creating a loop similar to this. Model is at /users/mjenson/matlab/ferro_hyst.mdl.

ferro_hyst.pnghyst_combo.png

  6529   Thu Apr 12 20:56:07 2012 DenUpdatePEMdaq

GUR1 XYZ, GUR2 XYZ, MC_F channels are now recorded at 256 Hz.

EDIT by JCD:  What Den means to say here is that (a) he modified some .ini files, and (b) he restarted the fb.

  6528   Thu Apr 12 14:48:44 2012 SureshUpdateSUSlocal damping and WFS

    WFS servo is moving the MC mirror angles to minimise TEM01 and TEM10 modes within the MC cavity.    This means it will compensate not only for angular noise in the mirrors but also for the PSL beam pointing fluctuations.  So the extra "noise" we see when WFS loops are on is because they are active below the WFS UGF of about 2 Hz.  Also if the HEPA airflow is above 20% (of its max), the PSL beam jitter (caused by the airflow) will add broadband noise into the WFS servo loops and this will show up in the OSEM signals.  See elog 5943 for details.

 

 

Quote

    ......            

Then I compared MC1, MC2, MC3 suspos, suspit, susyaw and susside positions with WFS on (black curve) and off (red curve). WFS add noise to MC1 and MC3 measured by osems (MC2 is fine though). WFS should change osem readings but is it a correct way to do this below 0.5 Hz (?) It looks like just a flat noise. Need to think about the conclusion.

 

 wfsmc1.png                      

 

 

 

  6527   Thu Apr 12 08:49:14 2012 DenUpdateSUSlocal damping and WFS

I tried to figure out what can add noise below 0.5 Hz to the MC_F. I compared MC1, MC2, MC3 suspos, suspit, susyaw and susside positions with damping (black curves) and without (red curves). Local damping is fine.

 mc1.png        mc2.png          mc3.png

Then I compared MC1, MC2, MC3 suspos, suspit, susyaw and susside positions with WFS on (black curve) and off (red curve). WFS add noise to MC1 and MC3 measured by osems (MC2 is fine though). WFS should change osem readings but is it a correct way to do this below 0.5 Hz (?) It looks like just a flat noise. Need to think about the conclusion.

 

 wfsmc1.png           wfsmc2.png            wfsmc3.png

  6526   Thu Apr 12 01:17:56 2012 SureshUpdateIOOBeam Profile measurement: IPPOS beam: Possible Clipping

[Suresh, Jenne]

  The input beam is most probably being clipped at the Faraday Isolator.  

Evidence: 

a)  The beam scan of the IPPOS beam showed a nongaussian beam in the horizontal direction.  This was visible in the beam scan since it overlays a gaussian-fit over the data.

b)  I was able to remove this departure from gaussian profile by introducing an offset of 5 into the C1:IOO-WFS2_YAW_OFFSET.  

c)   We made a few measurements of the beam diameter as a function of distance at an offset of 7.  At a distance of beyond 3 m the deviation from gaussian profile was once again apparent. 

d)  We increased the offset to 14 to remove this deviation. 

e)  When we measured the beam diameter again with this new offset the horizontal diameter and vertical diameters dropped by 2.sigma.  Indicating there the beam was clipped till then.

f)   We increased the offset to 16 and the beam diameter did not change further (within 1.sigma). Implying no more clipping, hopefully. 

And then the earthquake stopped us from proceeding further. 

We plan to investigate this further to be sure..  Data attached.

 

Subsidiary effects to keep track of:

1) Introducing an offset into the WFS loops decreases the coupling from PSL into MC. 

2) If the beam is being clipped at the Faraday Isolator then the REFL beam would also show lesser clipping with WFS offsets.

Attachment 1: BeamProfileData_IPPOS_2.xlsx
  6525   Thu Apr 12 00:40:45 2012 JenneUpdateSUSPRM, BS oplevs off

There's a beam dump after the HeNe on the BS oplev table, since the IPPOS measurement optics (steering mirrors) are in the way of the oplev beams. 

Don't enable the BS or PRM oplevs!!!!  We'll post a notice in the elog when the oplevs are back to normal. 

Self, remember to disable the oplevs manually if they come on with any restore scripts.

  6524   Thu Apr 12 00:16:38 2012 JenneUpdateEnvironmentEarthquake - moderate

 


M4.7 - Santa Isabel, Mexico 2012-04-12 06:48:38 UTC

Mode Cleaner doesn't want to stay locked.  Seismic is coming down from an earthquake ~20min ago.  

We're in the process of measuring IPPOS, so this is obnoxious.

EDIT:  Followed by a 6.2 and a 7.1 at 07:06UTC and 07:15UTC in the same area.

We're following the tried and true tradition of going home when there's an earthquake big enough that the MC won't stay locked.

Several optics have rung up, PRM is the only one which has tripped so far, because the side sensor has the extra gain, but the watchdog threshold is set for the face OSEMs.

  6523   Wed Apr 11 22:48:39 2012 ranaUpdateEnvironmentBLRMS

seis_blrms.png

  6522   Wed Apr 11 18:19:51 2012 JenneUpdateIOOMode matching recollections and conclusions

Another histogram.  This one allows the MMT mirror positions to move, the MMT incident angle for both curved optics to change, and the MC waist size and position to change.  The error quoted for the MC waist size measurement from 2010

was +\- 0.01mm, and the MC waist position was +\- 28mm.  

This histogram is showing that we're pretty sensitive to the MC waist measurement, which is used to define the beam.  We can be up to ~2% off in our ideal mode matching to the arms if we're using the incorrect initial beam for the telescope design.

ModeMismatch_MMTpos_MMTang_MCw0_MCwz_change_LowRes.png

  6521   Wed Apr 11 17:56:26 2012 JenneUpdateGeneralSummary of things to figure out with the IFO

Questions:

Power recycling gain

   * It should be ~40, but we observe/measure it to be ~7.  Even if mode matching of ~50% is assumed, gain is calculated to be ~15

   * Would like to measure PR gain independent of mode matching, if possible

Power recycling cavity mode matching

   * Reflectivity of PRMI was measured to be ~50%.  That's pretty high.  What's going on?

   * Even if we're mode matched to the arm, are we appropriately mode matched to the PRC?

Is beam from MC clipped in the Faraday?

   * We had to use MC axis for input pointing since PZTs aren't totally working.

   * Need to measure IPPOS beam for different MC alignments to see if horizontal waist measurement stays constant.

PRM flipped?

   * Not likely, but it can't hurt to confirm for sure.

   * Want to know, since it could give us a different plan for MMT moving than if the PRM is correct.

Thick optic non-normal incidence in IPPO - does this exaggerate astigmatism, which would help explain IPPOS measurement?

Is PRC waist same size / position as arm cavity waist, given the current "known" positions of all the optics?

   * How is this effected by moving the PRM?

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

Measurements to take and what information they give us:

IPPOS beam scan, with MC as-is

   * Confirm (or not) IPPOS measurements from last week

IPPOS beam scan with different MC alignments

   * Will tell us about Faraday clipping, if any

AS beam scan, misaligned PRM, misaligned SRM, misaligned ITMX, single bounce from ITMY

   * Can only take this measurement if beam is bright enough, so we'll just have to try

   * Will confirm IPPOS measurement, but includes going through the thick PRM, so can compare to calculated intra-PRC mode

REFL beam scan (already done....is the data satisfactory? If so, no need to redo), single bounce off of PRM

   * Will tell us about the potential PRM flipping

   * Need to compare with calculated mode at REFL port for flipped or non-flipped PRM

Look at POP camera, see 2nd pass through cavity

   * Try to match 1st and 2nd pass.  If they don't match, we're not well matched to PRC mode

Look at beam directly on ETMY cage, then beam from ETM, bounce off ITM, back to ETM cage

   * If the beams are the same size, we're well matched to arm cavity mode

   * Use fancy new frame-grabber.

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

MMT code things to calculate, and what information it gives us:

REFL beam path, for PRM flipping comparison

Thick IPPO non-normal incidence - I'm not sure how to do this yet, since I only know how non-normal incidence changes effective radii of curvature, and this is a flat optic, so *cos(theta) or /cos(theta)  won't do anything to an infinite RoC

Compare PRC waist to arm cavity waist, using "known" optic positions

Mode matching sensitivity to MC waist measurements

Mode matching sensitivity to PRM position

  6520   Wed Apr 11 16:33:16 2012 JenneBureaucracyGeneral40m Meeting Action Items

Action Items from Last Week:

(non-existant)

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

Action Items this Week and LEAD PERSON:

Assemble and ship 4 TTs from LHO - SURESH

Prepare electronics for TTs (coil drivers) - JAMIE

In-air TT testing to confirm we can control / move TTs before we vent (starting in ~2 weeks) - SURESH

Connect TTs to digital system and controls, lay cables if needed - JAMIE with SURESH

OAF comparison plot, both online and offline, comparing static, adaptive and static+adaptive - DEN

Static-only OAF noise budget (Adaptive noise budget as next step) - DEN

Black glass: big baffle pieces to clean&bake, get small pieces from Bob, put into baskets, make new basket for 1" pieces, get to clean&bake - KOJI

IPPOS beam measurement - SURESH with JENNE

AS beam measurement (if beam is bright enough) - SURESH and JENNE

Mode matching calculations, sensitivity to MC waist measurement errors, PRM position - JENNE

Summary of IFO questions, measurements to take, and game plan - JENNE

Think up diagnostic measurement to determine mode matching to PRC while chambers are open, while we tweak MMT - JAMIE, JENNE, KOJI, SURESH

  6519   Wed Apr 11 14:34:48 2012 JenneUpdateEnvironmentPlumbing guys are here

Quote:

I don't know why, but they're looking around on the roof, and inside our ceiling above the bathrooms.

 Bob tells me that the carpenter is going to move the nitrogen bottles to the other side of the outside door, so that the plumbers can install a safety shower / eyewash right outside our door.

Also, the carpenter just mounted a new glass door cabinet from Bob's lab in the IFO room, so we have some new storage space.

  6518   Wed Apr 11 12:25:11 2012 RyanUpdateComputersUpdating aLIGO Conlog

Over the next few days, I will be working on upgrading the aLIGO Conlog install to include new bugfixes distributed by Patrick T.  The currently running conlog *should* not be affected, but please let me know if it is (ryan.fisher@ligo.org).

  6517   Tue Apr 10 23:56:44 2012 ranaUpdateComputersSensoray

Now that Mike has got the Sensoray working, Jenne/Suresh should grab some new images of the ETM cage as Keiko did so that we can analyze them for another mode matching diagnostic.

  6516   Tue Apr 10 17:02:29 2012 JenneUpdateIOOMode matching recollections and conclusions

...Mostly just recollections at this point.

I re-looked at the mode matching's sensitivity to misplaced optics.  Here is the plot that the original MMT code from 2010 spits out:

IMMT_positionSensitivity_plotted10Apr2012_LowRes.png

What this plot is telling us is that we should lose no more than 0.1% of mode matching "goodness" if we messed up the curved optic's positions by up to 2 cm.  If we can't place optics to within 2 cm, we might as well go back to optics kindergarten, because that's pretty lame.

UPDATE: Here is a histogram using the new code, which definitely includes the non-unity index of refraction for the transmissive optics and the Faraday.  The only optics which are permitted to move are the 2 curved optics, and they are allowed a stdev of 20mm.  Again, we shouldn't be doing worse than ~99% mode matching, even if we're 2cm off from the MMT positions that we measured with a ruler.  This histogram only has 300 iterations, since it takes quite a while (~0.5sec) to calculate each iteration.  Note this is mode overlap using the measured MC waist, propagated through optics, compared to the ideal arm mode.  This is completely ignoring the IPPOS measurements so far.

Histogram_20mmStDev_MMTmovesOnly_LowRes.png

 

UPDATE 2: Allowed 5 degrees of incident angle motion for both curved optics, which changes the astigmatism of the beam downstream.  Still, no big change from ~99% mode matching efficiency.  Again, this doesn't include any information from the IPPOS measurements.  3000 iterations this time around, since I didn't need my computer.  Curved optics still allowed to move back and forth by 2cm. 

Histogram_20mmStDev_MMTmovesAndTilts_LowRes.png 

More meditations and conclusions to follow...  currently running hist code to allow tilt of optics, to account for astigmatism changes also. 

Suresh and I are going to do some beam measurements tomorrow with the beamscanner, and then we will do a few measurements with the razor blade technique, to confirm that we're doing things okey dokey.

  6515   Tue Apr 10 13:42:54 2012 JenneUpdateEnvironmentPlumbing guys are here

I don't know why, but they're looking around on the roof, and inside our ceiling above the bathrooms.

  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.

  6513   Mon Apr 9 20:02:19 2012 Mike J.UpdateComputersSensoray

The highest resolution available is 720x480 pixels. Bit depth of captured images and video is most likely 16 bits per pixel. Video may be captured raw as well, which will be necessary for image subtraction/enhancement, however it cannot currently be played raw. A captured image is shown below, along with MP4 video.

out_0.jpg

 

  6512   Mon Apr 9 18:18:14 2012 kiwamuUpdateLSCDRMI time series

Here is a time series when the DRMI is being locked.

You can see that the AS110 goes up because the SRCL is engaged and amplifies the 55 MHz sidebands.

 time_series1.png

  6511   Mon Apr 9 17:03:38 2012 DenUpdateEnvironmentLms vs Wiener

I tried to figure out why offline LMS filter subtract seismic noise much better from MC_F then the Wiener filter. I did the calculations twice - with my codes and with Matlab in-build functions, the results are the same. So this is not a code error.

The coherence between GUR 1, 2 and MC_F is still poor. Wiener filter is linear and its performance is confined to the frequency ranges where we see coherence. Lms filter is non-linear and it may be possible to subtract the noise even if non-linear effects are present in the system.

gur12_mcl.png

I've checked seismometer readout box again. I've soldered 50 Ohms to plus and minus inputs to VERT 1,2 N/S 1,2, E/W 1,2 - GUR 1 and 2 use these channels. Then I put the box back and connected it to the ADC.

seismboxnoise.png

The plot shows that the readout box noise is below the ADC noise. It is possible that amplifiers introduce non-linear effects. To check this I plotted the coherence between OSEM sensors and GUR1X signal:

gur1_osem.png

The coherence between OSEM sensors and GUR1X is pretty good, so may be witness path is not responsible for low coherence at 0.1 - 0.5 Hz between MC_F and GUR 1,2. IT seems that MC_F is bad at low frequencies. I terminated the input to the Channel 1 of the Pentek Generic board, where MC_F is plugged in.

mcl_noise.jpg

ADC is also good. Something else is wrong.

  6510   Mon Apr 9 15:09:34 2012 JenneUpdateLSCLocked MICH

Quote:

I was going to try some locking, but things are a little too noisy. 

Just so Kiwamu knows what I did today, in case he comes back....

I ran LSCoffsets, and aligned both X and Y arms and saved their positions, and aligned MICH, and saved the BS position. 

I'll play with it more later, when there aren't trucks driving around outside that I can hear / feel in the control room.

 After giving up on locking, the MC is getting unlocked every now and again (2 times so far in the last few minutes) from transient seismic stuff.

  6509   Mon Apr 9 15:02:30 2012 JenneUpdateLSCLocked MICH

I was going to try some locking, but things are a little too noisy. 

Just so Kiwamu knows what I did today, in case he comes back....

I ran LSCoffsets, and aligned both X and Y arms and saved their positions, and aligned MICH, and saved the BS position. 

I'll play with it more later, when there aren't trucks driving around outside that I can hear / feel in the control room.

  6508   Sat Apr 7 06:58:34 2012 kiwamuUpdateLSCDRMI lock : lost good alignment

Somehow I lost the good alignment, where the lock can be frequently acquired and hence I didn't go further ahead.

I will try locking the DRMI during the weekend again. My goal is to take time series when the DRMI is being locked and sensing matrix.

Quote from #6506

Currently SRM is slightly misaligned such that the MICH optical gain at AS55Q doesn't increase so much with the presence of SRM.

With this condition I was able to acquire the lock more frequently than how it used to be on the Wednesday.

The next step is to gradually align SRM, to optimize the controls and to repeat this process several times until SRM is fully aligned.

 

  6507   Sat Apr 7 02:01:29 2012 Mike J.UpdateComputersProjector Cable Management

I replaced the projector video and power cables with longer ones, and zip-tied them to the ceiling and wall so they don't block the image.

projector_cables.jpg

  6506   Sat Apr 7 01:56:05 2012 kiwamuUpdateLSCOSA signal in DRMI condition

It wasn't a dream or illusion -- I was locking the DRMI to the right condition last Wednesday (#6489).

Here is a snap shot of the AS-OSA signal taken today when the DRMI was locked with the same control settings (#6489).

The blue curve is data taken when the PRMI was locked for comparison.

You can see that both the upper and lower 55 MHz sideband are amplified by the SRC.

OSA.png

 

(Some notes)

Currently SRM is slightly misaligned such that the MICH optical gain at AS55Q doesn't increase so much with the presence of SRM.

With this condition I was able to acquire the lock more frequently than how it used to be on the Wednesday.

The next step is to gradually align SRM, to optimize the controls and to repeat this process several times until SRM is fully aligned.

Quote from #6489

A first thing I tried was : flipping the control sign of the SRCL while keeping the same control setups for the PRCL and MICH.

Occasionally the DRMI was "sort of" locked and hence I believe this setup must be a good starting point.

  6505   Sat Apr 7 01:45:02 2012 Mike J.UpdateComputersEven Better Hysteresis Model and Plots

 The new hysteresis model is slightly based on the SHO equation, but with the force being out of phase with the position by an amount of hysteresis {x(t)=Amp*sin(freq*t), F(t)=Amp*sin(freq*t+Hyst)}. The new model can be found at /users/mjenson/matlab/hyst_v_3.mdl.  Pictures are: new hysteresis model, x(t) subsystem in new model[xh''(t) only lacks -1 multiplier and includes hysteresis variable], new plots.

 hyst_v_3.pnghyst_v_3-x(t).pnghyst_v3.png

  6504   Sat Apr 7 00:31:12 2012 keikoUpdateLSCRAM simulation for Full ifo

I didn't understand how CARM can be decreased 2 orderes of magnitude and PRCL can be INCREASED by such small offsets (see the matrix quoted).

Apparently it was because of an optical-spring ish effect from the "detuning" (which is actually RAM position offsets). I put two plots which are CARM and PRCL tranfer functions to REFL f1 or POP f1, when there is a slight PRCL offset (0, 1e-14m, and 1e-15m cases are plotted). Looking at these plots, it was not a good idea to calculate the LSC matrix in DC because they are affected by this detuning a lot. I'll try f = 150 Hz for the matrix.

plot4a.pngplot4b.png

Quote:

*** Iteration *** 

%*.*.*. Resulting matrix w/ RAM .*.*.*

REFL f1 : 0.039125    -0.000000    0.003665       0.000005    -0.000007 

  AS f2 : 0.000010    1.000431    0.000009       -0.003500    -0.000002 

 POP f1 : 156.420221    -0.000246    15.586838    0.019406    -0.000154 

 POP f2 : 1.255806    -0.154275    0.047313       1.000008    0.024285 

 POP f2 : -34.814720    -0.006600    -1.884850    0.042950    1.000000 

Offsets converged to:

PRCL =  2.1e-15, MICH = 1.1e-17, SRCL = -3.8e-15, CARM = 2.2e-16, DARM = 0  

  6503   Fri Apr 6 20:38:41 2012 Mike J.UpdateComputersSensoray

 Turns out that the "MPEG-4 VES" video format is just bad for captured video.  Everything except "MP4" and "MPEG-TS" works for streaming, and "MP4" and "MPEG-TS" seem to be the only captured formats that can be viewed properly.

  6502   Fri Apr 6 20:24:31 2012 Mike J.UpdateComputersSensoray

The Sensoray device is currently viewing Monitor 4 and plugged into Pianosa.  The user interface is run at /home/controls/Downloads/sdk_2253_1.2.2_linux/python demo.py. It can preview and capture the video stream, however the captured files are terrible. I believe it has something to do with the bitrate, since the captured video with lower bitrates are not as bad as the ones with higher bitrates, but  I am not certain.

  6501   Fri Apr 6 20:05:12 2012 JamieSummaryGeneralLaser Emergency Shutoff

We reset the interlock and restarted the PSL.  The end AUX lasers seem to have come back online fine.  PMC and mode cleaner locked back up quickly.

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