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ID Date Author Type Category Subjectup
  896   Fri Aug 29 10:20:32 2008 YoichiConfigurationPSLbeam block distorted

Quote:
There was a beam block after the Mach Zender. Who or what put this there?

The going to the MC now looks distorted as if someone has left something funny in the beam or maybe the new PMC has started to degrade??

Use the ELOG people...its good for you.


I put the block. I was frequently reaching to the FSS box to change the test point probes. I put the block to protect my hands/clothes from being burnt accidentally.
  902   Fri Aug 29 16:35:18 2008 YoichiConfigurationPSLbeam block distorted

Quote:
There was a beam block after the Mach Zender. Who or what put this there?

The going to the MC now looks distorted as if someone has left something funny in the beam or maybe the new PMC has started to degrade??

Use the ELOG people...its good for you.


The apparent distortion of the MC refl. was caused by mis-alignment of the MC mirrors.
Because the MC1 was mis-aligned, the reflected light was clipped by a steering mirror.
I restored the MC angle bias values from the conlog history and now the MC locks.
According to conlog, the MC alignment was changed at around 18:30 on Thursday PDT.
It could have been caused by the computer reboots.
  9420   Thu Nov 21 10:24:50 2013 KojiUpdateSUSbeam dumps

You don't need the fourth glass piece on the diamond beam dump.

  9448   Fri Dec 6 15:57:41 2013 SteveUpdateIOObeam dumps for PSL pointing monitoring

Quote:

Since the pointing has gone bad again, I went to the PSL to investigate. Found some bad things and removed them:

1) There was a stopped down iris AGAIN in the main beam path, after the newly installed mirror mount. I opened it. Stop closing irises in the beam path.

2) The beam dump for the IOO QPD reflection was just some black aluminum. That is not a real dump. I removed it. We need two razor blade dumps for this.

3) There was an ND filter wheel (???) after one of the PMC steering mirrors. This is not good noise / optics practice. I removed it and dumped the beam in a real dump. No elog about this ?!#?

 

The attached trend shows the last 20 days. The big step ~2 weeks ago is when Steve replaced the steering mirror mount with the steel one. I don't understand the drift that comes after that.

 

Today I also spent ~1 hour repairing the Aldabella laptop. Whoever moved it from the PSL area to the SP table seems to have corrupted the disk by improper shutdown. Please stop shutting the lid and disconnecting it from the AC power unless you want to be fixing it. Its now running in some recovery mode. Lets leave it where it is next to the PSL and MC1.

I steered the MC suspensions back to where they were on the trends before the PSL mirror mount swap and then aligned the PSL beam into it by touching the last 2 steel mounts. Once the alignment was good without WFS, I centered the beams on the IOO QPDs. If it behaves good overnight, I will center the unlocked beams on the MC WFS.

 

Please stay off the PSL for a couple days if you can so that we can watch the drift. This means no opening the doors, turning on the lights, or heavy work around there.

 IOO pointing monitoring qpds received razor beam dumps on their refs.

The Pos QPD was rotated and recentered.

The Ang QPD was left untouched.

TREND plot of 23 days is attached.

Attachment 1: IOO_QPD_MONS.jpg
IOO_QPD_MONS.jpg
Attachment 2: PointingTrend23d.png
PointingTrend23d.png
  9974   Tue May 20 11:48:22 2014 SteveUpdateSUSbeam dumps added to ETMX_ISCT

Anodized aluminum dumps replaced by 6 razor beam dumps.

Two more razor beam dumps added this afternoon.   The picture will updated tomorrow.

Attachment 1: razorbeamdumps.jpg
razorbeamdumps.jpg
Attachment 2: razorbeamdumpss.jpg
razorbeamdumpss.jpg
  9325   Fri Nov 1 09:45:32 2013 SteveUpdateIOObeam dumps to be find

Quote:

Quote:

Steve, can you please put 2 mounted  razor dumps near the WFS for this purpose??    

            Tuesday: Razor dumps are waiting for you.

 I couldn't find any dumps near the WFS. Koji looked. I looked twice. Maybe they are spooky and absorbing all of the light?

The MC alignment was bad and the WFS were making it drift. Koji aligned the beam into the PMC. I then restored the MC suspensions to where they were 8 days ago (back when the transmission and reflection were good). With the WFS OFF, this gave us a MC trans ~ 16000. With WFS ON it goes to 17500 which is about as good as its been over the last 80 days.

I centered the beam on the WFS with the MC unlocked and also centered the beam on the whole WFS path (it was near clipping between WFS 1 & 2). Also for some reason that beamsplitter which steers the beam onto WFS1 is a R=33% (!? why is this not a R=50% ??).

Steve, please swap this out to a BS1-1064-50-1025-45S if we have one sitting around. If not, we want to add this to the CVI purchase list, but not buy until we get a bigger list together.

I also centered this newly aligned beam into the IMC onto the PSL QPDs. We should now use these as a pointing reference for the beam into the IMC.

While doing this I noticed that the beam was almost clipping on the Uniblitz shutter used to block the PSL beam. That shutter is mounted too short and was also not centered horizontally. I removed it for now so that Steve can find a more adjustable mount for it and put it back into play. The beam going into the IMC is BIG, so you have to very careful when centering the shutter. Might be that we cannot leave it at 45 deg and still get a big enough aperture.

Note #3 for Steve: please also replace the mount for last steering mirror into the IMC with a Polanski or a Superman, that black Ultima is no good. Also the dogs must be steel - no aluminum dogs for our sensitive places.

No wonder they could not find the beam dumps. Last night was Haloween. They should of just said: Trick or treat! where are the beam dumps?

Attachment 1: razor_beam_dumps.jpg
razor_beam_dumps.jpg
  7801   Sun Dec 9 01:21:51 2012 DenUpdateLSCbeam inside DRMI is clipping on PR3 Tip-Tilt

Quote:

 Today I wanted to check that AS and REFL beams are real and contain proper information about interferometer. For this I locked YARM using AS55_I and REFL11_I. Then I compared spectrum with POY11_I locking. Everything is the same. I've also adjusted phase rotations of AS55 (0.2 ->24) and REFL11 (-34.150 -> -43).

 I studied more carefully beam path inside DRMI using PRM face camera and found that beam is clipping on PR3 edge.

Step 1: PRCL LOCK, MICH LOCK, power build up 30.

Note: left is right and vice versa on the PRM camera

prcl_lock.mjpg

 Step 2: PRLC - UNLOCK, MICH - LOCK, PRM is still aligned. Right photo is AS port. I've slightly misaligned ITMs such that disturbance of AS beam is clearly seen.

PRM_UNLOCK.bmp       AS_UNLOCK.bmp

 

Step 3: PRCL - UNLOCK, MICH - LOCK, PRM misalined in yaw such such that the beam LASER -> PRM -> PR2 -> PR3 -> BS -> ITMX -> BS -> PR3 -> PR2 -> PRM -> PR2 -> PR3 is completely clipped on the TT edge. AS beam is now not clipped.

PRM_MISALIGN.bmp    AS_MISALIGN.bmp

So the conclusion is that when PRC is not locked and beam is thin, it can avoid clipping. When PRC locked, beam size grows and it starts to clip. I think we need to move the mount next to PR3 because of it we to not have enough space to align the TT.

Step 4: PSL shutter is closed.

PRM_BLOCK.bmp

  7802   Sun Dec 9 17:51:53 2012 ranaUpdateLSCbeam inside DRMI is clipping on PR3 Tip-Tilt

 

 Some explanation of how you define power buildup please. Also some plots showing the evidence.

  7803   Mon Dec 10 03:02:03 2012 DenUpdateLSCbeam inside DRMI is clipping on PR3 Tip-Tilt

Quote:

 

 Some explanation of how you define power buildup please. Also some plots showing the evidence.

 I think about power buildup as a ratio of the power in the cavity when it is locked and unlocked = (POYDC_LOCKED - POYDC_OFFSET) / (POYDC_UNLOCKED - POYDC_OFFSET). I do not multiply this number by PRM transmission.

POYDC_OFFSET = -0.006

POYDC_UNLOCK = 0.063

For example, on the plot below power buildup is 15.

PRCL_LOCK.png

  7804   Mon Dec 10 10:13:41 2012 DenUpdateLSCbeam inside DRMI is clipping on PR3 Tip-Tilt

 

That's OK, but its best to use standard notation. The power recycling gain is defined as the power incident on the BS divided by the power incident on the PRM from the laser side. You should also compare it with the PRC gain that you expect from mirror transmissions.

  7806   Mon Dec 10 22:34:34 2012 DenUpdateLSCbeam inside DRMI is clipping on PR3 Tip-Tilt

Quote:

 

That's OK, but its best to use standard notation. The power recycling gain is defined as the power incident on the BS divided by the power incident on the PRM from the laser side. You should also compare it with the PRC gain that you expect from mirror transmissions.

 I've made snapshots of PR2, PRM, ITMY and ITMX mirrors. Power buildup recycling gain (POWER BS / POWER PRM) was equal to 3-4.

PR2.bmp    PRM_LOCK.bmp    ITMY.png    ITMX.png

  7820   Thu Dec 13 03:20:48 2012 DenUpdateLSCbeam inside DRMI is clipping on PR3 Tip-Tilt

Quote:

 

 I've made snapshots of PR2, PRM, ITMY and ITMX mirrors. Power buildup recycling gain (POWER BS / POWER PRM) was equal to 3-4.

           

 We've looked at PR2 face camera when PRM, BS and one of the ITMs were aligned. We saw an extra beam at PR2 when ITMX was aligned (right plot). This spot stays on the PR2 when prcl is locked.

PR2_ITMX.png   PR2_ITMY.png

Then we looked at PR3 transmission mirror and saw that the main beam is not on the edge of the mirror. Secondary beam is clipping on the mirror mount of PR3 that we see on BS_PRM camera.

PR3_LOCK.png

Measured beam spot positions:

Optics Pitch, mm Yaw, mm
ITMX 5.6 1.5
ETMX -1.5 1.5
ITMY 4.8 -1.5
ETMY -1.4 5.6
PRM 2.7 4.1

"+" for pitch means that the beam is too high, "-" too low

"+" for yaw means that the beam is left if you look from the back, "-" is right

Beam spots were measured using x, y arm and prcl locking to the carrier.

  4039   Thu Dec 9 23:17:47 2010 kiwamuUpdateSUSbeam pointing has been done

[Koji, Osamu and Kiwamu]

 We aligned the beam axis pointing down to both X and Y arm.

Now the beams are hitting the centers of both ETMX and ETMY.

Amazingly Osamu made X arm flashing by aligning the cavity.


(what we did)

- opened almost all the chambers except for the MC2 chamber.

- locked and aligned the MC.

   We set Marconi to the right frequency, which had been set to the default values, probably due to the power outage in the last weekend.

   Also we found a DAC cable disconnected from the IO chassis of c1sus. So we connected it in order to damp the MC suspensions.

- aligned MMT2 and PZT2 in order to let the beam go through the center of PRM.

- checked the beam centering at the two TTs (PR2, PR3).

- rotated PR3 to make the beam go through the centers of both ITMY and BS at the same time.

- tried finding the beam spot at the ETMY chamber, and successfully found it.

    To see such faint beam spot, we used an IR viewer.

    In addition to that, we put a large piece of aluminum foil as a screen in the chamber.

- aligned the beam to the center of ETMY by tweaking the PZT mirror (SM2).

- aligned the BS so that the reflected beam at the BS goes through the center of ITMX.

- tried finding the beam spot at the X end, and successfully found it hitting the wall in the chamber.

- aligned the BS in order to let the beam hit the center of ETMX.

- tried aligning ETMX and ITMX to the beam.

Eventually we made the X arm flashing.

However the flash was a bit too weak to completely align the cavity.

 

(plan for tomorrow)

- reinstall some steering mirrors into the BS chamber

- check and neutralize PZT1

- alignment of IP_ANG

 

  4040   Fri Dec 10 09:58:57 2010 AidanUpdateSUSbeam pointing has been done

Good news. I feel multi-chromatic-locking success is just around the corner.

By the way, there's a new presentation on the DCC from the ANU group where they've locked a short single cavity with both colors - G1000735:

https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?docid=14040

 

 

Quote:

[Koji, Osamu and Kiwamu]

 We aligned the beam axis pointing down to both X and Y arm.

Now the beams are hitting the centers of both ETMX and ETMY.

Amazingly Osamu made X arm flashing by aligning the cavity.


 

  4874   Fri Jun 24 00:13:24 2011 kiwamuUpdateABSLbeam profile measurement of LWE

The beam profile of the LWE (LightWave Electronics) NPRO was measured.

Mode matching telescopes will be designed and setup soon based on the result of the measurements.

 

Here is a plot of the measured beam profile.

beam_profile.png

 (some notes)

The measurement was done by using Kevin's power attenuation technique (#3030).

An window was put just after the NPRO and the reflected beam was sampled for the measurement to avoid the beam scan saturated.

  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.

Attachment 1: 2010_09_10_w.mat
  7527   Thu Oct 11 11:20:05 2012 janoschUpdateGeneralbeam shape simulation, PRC

I started to create a Finesse model of the PRC cavity. We have the phase maps for the PRC and the two ITMs. I could not find anything for PR2,3 and BS. All files can be found in my SVN folder /janosch/PRC40m. I used the AutoCAD model to determine angles of incidence and distances. These numbers are largely inconsistent with numbers that you can find elsewhere on the 40m wiki, but this certainly depends on what accuracy is required for interferometer alignment and I don't understand anything about alignment.

The phase maps come in a format that needs to be modified before they can be used in Finesse. I have started with this work, but maybe someone else can take over. The phase maps show tilts and the PRC also has the curvature. These have to be subtracted out before the maps can be loaded into Finesse. I asked GariLynn for the code that they use. The Finesse model (MichPRC_40m.kat) does not load the phasemaps yet, and I just wrote some random parameter values for the TEM00 input beam to the PRC. So these Gauss parameters need to be corrected.

I will only go on with this work if Rana tells me that I should do so, otherwise it is on hold until we have a volunteer.

  4110   Wed Jan 5 03:06:02 2011 kiwamuUpdateIOObeam spots on MC mirrors

I checked the spot positions on MC1 and MC3 by running Yuta's A2L script.

The amounts of the off-centering were good except for YAW of MC1.

 So we have to adjust the YAW alignment of the beam axis by steering the mirrors at the PSL table.

- - - (measured off-centering) - - - 

MC1_PIT  =  -0.711 mm

MC1_YAW =  1.62 mm

MC3_PIT  =   -0.0797 mm

MC3_YAW  =  - 0.223 mm

 

Quote:

We will check the spot positions more accurately by A2L technique.

 

  528   Tue Jun 10 08:37:18 2008 steveUpdatePSLbeam trap is being tested
High power beam trap is being tested just west of FSS area on psl enclosure.

When the pmc is operating at low power that means that the rest of the 3W is going into the
circular SS trap.

Please beware of the high power beam trap test
Attachment 1: trapss3w.png
trapss3w.png
  6648   Thu May 17 15:31:22 2012 steveUpdateGeneralbeam trap posts & clamps for vacuum

 Aluminum posts and SS clamps for green glass traps in vacuum will be out of the shops by June 6, 2012 the latest

 

Attachment 1: 05161201.PDF
05161201.PDF 05161201.PDF
Attachment 2: 05151201.PDF
05151201.PDF
  5047   Wed Jul 27 15:38:01 2011 steveUpdateVACbeam traps for vacuum

We have cleaned, baked, rga scaned traps for vacuum. Thorlabs LB1 on 1" OD ss posts and forks. The effective surface area is 43 x 18 mm of stacked razors.

Seven pieces are mounted on New Focus #9962  1" OD SS vented-  pedestrals to 5.5" center height and 5 pieces to 4.875"

Attachment 1: P1080095.JPG
P1080095.JPG
  8087   Fri Feb 15 09:58:49 2013 SteveUpdateGeneralbeam traps ready to be installed

Black-green glass traps are ready for light in vacuum. I can assemble more if needed. These three sizes are available.

Attachment 1: IMG_0083.JPG
IMG_0083.JPG
Attachment 2: IMG_0084.JPG
IMG_0084.JPG
  8089   Fri Feb 15 16:09:19 2013 KojiUpdateGeneralbeam traps ready to be installed

For the hexagonal one, insert one of the glass plate only half. Use a 1"x.5" piece if exists.

For the diamond one, you don't need the forth glass piece.

 

Attachment 1: HexBeamDump.pdf
HexBeamDump.pdf
Attachment 2: DiamondBeamDump2in.pdf
DiamondBeamDump2in.pdf
  5872   Fri Nov 11 12:32:45 2011 KatrinUpdateGreen Lockingbeat PSL - YARM laser

[Suresh, Katrin]

Measured frequency fluctuation of the beat between PSL and YARM lasers.

beat_psl_y.png

Yesterday, it was very tricky to adjust the voltage offset to the slow YARM laser input to achieve the appropriate beat frequency. Today, it was much easier. During measurement beat around 25 MHz. Calibration factor 40 mV per 10 MHz.

  4211   Thu Jan 27 11:04:27 2011 KojiUpdateGreen Lockingbeat freq scan

Experiment in the night of Jan 26.

o The arm was locked for the IR beam and was aligned for it.
o The green was aligned to the arm
o The beat freq was observed with the RF analyzer and the webcam.
o Engaged the ALS servo
o Compared the fluctuation of the beat freq with and without ALS
o Scanned the beat freq in order to find an IR resonance

The beat freq was scanned. A resonance for IR was found.
However, the residual motion of the arm was not within the line width of the IR resonance.

 To Do
- Improve the ALS servo (==>Koji)
- VCO noise characterization (==>Suresh is on it)
- Calibrate the PLL feedback (i.e. ALS error) into Hz/rtHz (==>Suresh)
- Calibrate the end green PZT fb into Hz/rtHz (==>Osamu is on it)
- Tuning of the suspension filters to reduce the bounce mode coupling.


DETAILS

o How to lock the arm with IR

  • Coarsely align the arm without lock. Transmittion was ~300 with MCTRANS ~40000
  • REFL11I is the error signal. unWhiten filter (FM1) should be on.
  • Unlock the MC and null the error and the arm trans offset by running the following commands

ezcaservo -g -0.1 -r C1:LSC-REFL11_I_OUTPUT C1:LSC-REFL11_I_OFFSET
ezcaservo -g -0.1 -r C1:LSC-REFL11_Q_OUTPUT C1:LSC-REFL11_Q_OFFSET
ezcaservo -g 0.1 -r C1:LSC-TRX_OUTPUT C1:LSC-TRX_OFFSET

  • Confirm the input matrix to pass REFL11I to MC path (why don't we use XARM path...?)

ezcawrite C1:LSC-MTRX_81 1.0

  • Servo configuration
    • For acquisition: Gain of 2. Only FM1 (1000:10) has to be on.
    • After the acquisition (TRX>200): The gain is to be changed to 1. FM2 and FM3 can be turned on for the LF boost.
  • Actuator matrix: connect MC path to ETMX and MC2

ezcawrite C1:LSC-OM_MTRX_18 1.0
ezcawrite C1:LSC-OM_MTRX_78 1.0

 

o How to align the green beam

  • After the alignment I went the end and aligned the last two steering mirrors.


o The beat freq monitor

  • Put the RF analyzer at the RF splitter of the RFPD output.
  • Used Zonet webcam (http://192.168.113.201:3037) for the remote monitoring

 

o How to engage the ALS servo

  • Preparation:
    • VCO PLL feedback comes to X_FINE path.
    • Put an offset of -850 to cancel too big offset (when the VCO is unlocked)
    • Use Y_FINE channel for the offset addtion. FM1 is 10mHz LPF in order to make the offset smooth.
    • Add X_FINE and Y_FINE by the matrix.
  • Control
    • Turn off X_FINE out. Leave Y_FINE output turned on.
    • Turn on ETMX ALS path.
    • Servo setting: FM1 1000:30 ON, others OFF, gain1
    • Wait for the beat comes in to the locking range at around 80MHz.
    • If the peak is too far, sweep Y_FINE offset in order to . Or change GCV slow thermal offset to let the beat freq jump.
    • You may have ambiguity of the feedback sign depending on which green has higher freq.
    • After the capture of the ALS lock, increse the gain up to 20. Turn on 0.1:boost at FM3.

 

o Comparison of the stability of the beat freq (Attachment3)

  • The spectra of the VCO PLL feedback was measured.
  • First of all, the signal was measured without ALS (blue).
    The PLL lost lock quite frequently, so the careful adjustment of the offset was necessary.Still I think there was slight saturation upconversion.
  • Then, the ALS was turned on (red). The gain was 20. This is an in-loop evaluation of the servo. The suppression was ~1000 at 1Hz.

o Beat freq scanning

  • The following command was used for the beat note scanning 

ezcastep -- "C1:GCV-YARM_FINE_OFFSET" "5,500"

  • Once the IR transmission was found, the scan was stopped.
  • Because the resultant rms stability of the arm was not within the line width of the cavity, the smooth resonant curve was not obtained.
  • From the shape of the error signal the peak-to-peak displacement (f>1Hz) was estimated to be +/-0.7nm. The dominant displacement
    in the period is 16Hz component.

 

Attachment 1: arm_scan.pdf
arm_scan.pdf
Attachment 2: arm_cav_scan3.png
arm_cav_scan3.png
Attachment 3: 110126_ALS_inloop.pdf
110126_ALS_inloop.pdf
  4268   Thu Feb 10 05:06:35 2011 kiwamuUpdateGreen Lockingbeat noise : a little bit better, and 1Hz peak from amplitude noise coupling

 I repeated the same measurement as that Koji did before (see here) with the mixer-based frequency discriminator.

The frequency fluctuation of the beat note is now 50 kHz in rms integrated down to 0.1 Hz, which is a bit better than before.

However there still is the same undesired structure in the spectrum below 10 Hz.

 

 Screen_shot_2011-02-10_at_4.01.43.png

Fig.1 power spectra of the green beat note fluctuation in terms of frequency fluctuation.

   Red curves were taken when the IR was locked to the MC, and the green was locked to the X arm.

Blue curves were taken when both the IR and the green were locked to the X arm.

Black curve was also the one taken when the IR and the green were locked to the X arm, but showing the lower noise level.

I have no idea what exactly was going on when I took the black curve, but this noise level sometimes showed up.

The discrepancy may come from a kind of calibration error although I kept using the same calibration factor to convert the data from count to frequency.

Need more investigations.

 


 Additionally Koji and I took the coherence between the beat fluctuation and the transmitted lights of both the IR and the green.

It showed a strong coherence at 1 Hz, which is one of the dominant noise of the beat note.

This probably indicates that the 1 Hz peak is produced by a coupling from amplitude fluctuation.

Screen_shot_2011-02-10_at_4.52.13.png

 For monitoring the green transmitted light, I used the Jenne's PD (see here)

  6302   Tue Feb 21 22:06:18 2012 jamieUpdateLSCbeatbox DFD installed in 1X2 rack

I have installed a proto version of the ALS beatbox delay-line frequency discriminator (DFD, formally known as MFD), in the 1X2 rack in the empty space above the RF generation box.

That empty space above the RF generation box had been intentionally left empty to provide needed ventilation airflow for the RF box, since it tends to get pretty hot.  I left 1U of space between the RF box and the beatbox, and so far the situation seems ok, ie. the RF box is not cooking the beatbox.  This is only a temporary arrangement, though, and we should be able to clean up the rack considerably once the beatbox is fully working.

For power I connected the beatbox to the two unused +/- 18 V Sorensen supplies in the OMC power rack next to the SP table.  I disconnected the OMC cable that was connected to those supplies originally.  Again, this is probably just temporary.

Right now the beatbox isn't fully functioning, but it should be enough to use for lock acquisition studies.  The beatbox is intended to have two multi-channel DFDs, one for each arm, each with coarse and fine outputs.  What's installed only has one DFD, but with both coarse and fine outputs.  It is also intended to have differential DAQ outputs for the mixer IF outputs, which are not installed in this version.

The intended design was also supposed to use a comparator in the initial amplification stages before the delay outputs.  The comparator was removed, though, since it was too slow and was limiting the bandwidth in the coarse channel.  I'll post an updated schematic tomorrow.

I made some initial noise measurements:  with a 21 MHz input, which corrseponds to a zero crossing for a minimal delay, the I output is at ~200 nVrms/\sqrt{Hz} at 5 Hz, falling down to ~30 nVrms about 100 Hz, after which it's mostly flat.  I'll make calibrated plots for all channels tomorrow.

The actual needed delay lines are installed/hooked up either.  Either Kiwamu will hook something up tonight, or I'll do it tomorrow.

  6794   Mon Jun 11 21:50:08 2012 yutaUpdateGreen Lockingbeatbox looks OK

Summary:
  We need I-Q frequency deiscriminator to control the arm length fine and continuously.
  I checked the beatbox (LIGO-D1102241-v4; see elog #6302) and it was working.

What I did:
  1. Measured some transferfunctions with a network analyzer (Aligent 4395A) and checked the cabling is correct.

  2. Put 30 m/1.5 m delay line and checked I-Q outputs are actually orthogonal. I did this by sweeping the frequency of RF input to the beatbox. See attached picture. You can see nice circle on the oscilloscope.

Some measurement results:

  - Gains of the transferfunctions(@ 10-100MHz) between;

   RF in -> RF mon: -25 to -20 dB
   RF in -> fine delay out: -50 to -40 dB
   RF in -> coarse delay out: -50 to -40 dB
   RF in -> LO of mixer RMS-1: ~ +4 dB  (RMS-1 needs +7 dB LO)
 
  - 30m delay line(RG-142B/U) had -2 dB loss.

Note:
  - RF input must be larger than about -3 dBm to get enough LO to the mixer. Otherwise, you won't get I-Q outputs.
  - The comparator, whitening filter and differential DAQ outputs are not installed in the current beatbox.
  - Current beatbox only has electronics for the one arm.
  - The print on the board D1102241 says +15V and -15V, but they are actually opposite. Cabling is swapped in order to supply correct power to the ICs.

Attachment 1: CIMG1522.JPG
CIMG1522.JPG
  734   Thu Jul 24 11:49:07 2008 MashaSummaryAuxiliary lockingbelated weekly summary
I designed a high pass filter to whiten the spectrum from the Mach Zehnder to optimize the
input into the ADC. The swept sine response measurement and the effect of the filter on the
spectrum are attached. If I start using the digital system (it is currently down in Bridge),
I will decide if the filter needs to be improved/better matched to the ADC there.

I moved from the 40m to Rana's lab in bridge. I am making a new and improved Mach Zehnder
setup with a 50m fiber in one arm; currently the transmission through the fiber is 44%. I
am working out how to mode match the laser to the fiber to improve this number.
Attachment 1: filter_tr_function.pdf
filter_tr_function.pdf
Attachment 2: filtered_spectr0724.pdf
filtered_spectr0724.pdf
  7342   Tue Sep 4 20:25:22 2012 jamieOmnistructureVACbetter in-air "lite" access connector needed

We really need something better to replace the access connector when we're at air.  This tin foil tunnel crap is dumb.  We can't do any locking in the evening after we've put on the light doors.  We need something that we can put in place of the access connector that allows us access to the OMC and IOO tables, while still allowing IMC locking, and can be left in place at night.

  7343   Wed Sep 5 09:50:25 2012 SteveOmnistructureVACbetter in-air "lite" access connector needed

Quote:

We really need something better to replace the access connector when we're at air.  This tin foil tunnel crap is dumb.  We can't do any locking in the evening after we've put on the light doors.  We need something that we can put in place of the access connector that allows us access to the OMC and IOO tables, while still allowing IMC locking, and can be left in place at night.

 It is in the shop. It will be ready for the next vent. Koji's dream comes through.

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  7344   Wed Sep 5 10:50:15 2012 jamieOmnistructureVACbetter in-air "lite" access connector needed

Quote:

Quote:

We really need something better to replace the access connector when we're at air.  This tin foil tunnel crap is dumb.  We can't do any locking in the evening after we've put on the light doors.  We need something that we can put in place of the access connector that allows us access to the OMC and IOO tables, while still allowing IMC locking, and can be left in place at night.

 It is in the shop. It will be ready for the next vent. Koji's dream comes through.

 Can we see the full design?  If we can't lock the mode cleaner with this thing on then it's really of no use.  We want it to be equivalent to the light doors, but allow us to keep the mode cleaner locked.  That's the most important aspect.

  7345   Wed Sep 5 13:11:43 2012 jamieOmnistructureVACbetter in-air "lite" access connector needed

Quote:

Quote:

Quote:

We really need something better to replace the access connector when we're at air.  This tin foil tunnel crap is dumb.  We can't do any locking in the evening after we've put on the light doors.  We need something that we can put in place of the access connector that allows us access to the OMC and IOO tables, while still allowing IMC locking, and can be left in place at night.

 It is in the shop. It will be ready for the next vent. Koji's dream comes through.

 Can we see the full design?  If we can't lock the mode cleaner with this thing on then it's really of no use.  We want it to be equivalent to the light doors, but allow us to keep the mode cleaner locked.  That's the most important aspect.

 It also needs to be wide enough that the MMT beam can go through, so that we can not only lock the MC, but also work on the rest of the IFO.

  7952   Tue Jan 29 10:59:37 2013 lazy personFrogsGeneralbetter plan

 

 I propose we work around this problem with giant flip-flops.  These are in the vein of the take-off-your-shoes-and-put-on-Crocs, without the taking off your shoes part.  They're a little annoying on the sticky mats, but otherwise great.  They are also super easy to put on and take off without hands, so there's no excuse for wearing them around the control room. 

I propose we buy many pairs of the smalls in green (since we already have one green small...they are big on me, so should be just right for most people), and a few mediums in, say, blue, and a few larges in black, and then maybe a few extra larges in green for people with extraordinarily large feet (they only have 3 colors).  Then we can keep a few pairs of each by each door to the lab, and have no more tracking dirty control room filth into the lab.

  2670   Fri Mar 12 17:08:22 2010 steveConfigurationVACbg-RGAscan at d18

RGA scan of rga-region only at day 18   This is the back ground of the rga with some calibration gas.

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  11040   Mon Feb 16 21:52:51 2015 ranaHowToTreasurebig Dataviewer windows

Following this entry, I have made the same change in the controls account on rossa:

In the ~/.grace/gracerc file (create one if it doesn't exist), put in a line which reads:

PAGE LAYOUT FREE

Now we can scale our dataviewer live and playback plots by stretching the window with our mouse. The attached screenshot shows how I filled up one of the vertical monitors with a DV window for arm locking.

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  15680   Tue Nov 17 13:24:40 2020 ChubUpdateGeneralbig UPS on the way

Ordered 11/16 from CDW, on PO# S492940, the high voltage Tripp Lite SMART5000XFMRXL  for TP-1.  Should be arriving in about a week.

  894   Thu Aug 28 19:02:25 2008 rana, josephb, robSummaryComputersbig boot
This afternoon Joe did something with an .ini file (look for his detailed elog entry) and the computers went bad.
RFM network screen not active - filter modules not working.

We went around and booted every machine as has been done before. The correct order for a memory corruption
fixing big boot is the following:

    [1] RESET the RFM switches near the FB racks.
    [2] Power cycle c1dcuepics.
    [3] Power cycle all other crates with real time CPUs:
    c1iscey, daqctrl, daqawg, c1susvme1, c1susvme2, c1sosvme, c1iovme, c1lsc, c1asc, & c1iscex
    [4] Start up all FEs as described in Wiki.
    [5] Burt restore everyone (losepics, iscepics, assepics, omcepics?)
  13731   Thu Apr 5 13:46:42 2018 gautamUpdateSUSbig earthquake

Seems like there was a 5.3 magnitude EQ ~10km from us (though I didn't feel it). All watchdogs were tripped so our mirrors definitely felt it. ITMX is stuck (but all the other optics are damping fine). I tried the usual jiggling of DC bias voltage but ITMX still seems stuck. Probably a good sign that the magnet hasn't come off, but not ideal that I can't shake it free..

edit: after a bit more vigorous shaking, ITMX was freed. I had to move the bias slider by +/-10,000 cts, whereas initially I was trying +/-2000 cts. There is a tendency for the optic to get stuck again once it has been freed (while the optic's free swinging motion damps out), so I had to keep an eye out and as soon as the optic was freed, I re-engaged the damping servos to damp out the optic motion quickly.

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  7923   Tue Jan 22 09:10:19 2013 SteveUpdatePEMbig foot is dirty

Please wipe, clean car wheels and wear booties entering the 40m lab.

Obviously this person has no idea about our clean room rules.

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  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.

  3490   Mon Aug 30 22:45:49 2010 kiwamuUpdateCDSbinary outputs for the new CDS

{ Joe and Kiwamu }

Today we made some efforts to get the binary outputs (BOs) working.

They still are not working but the situation is getting better.

    So far the BO cards were not recognized by any realtime codes when we ran the codes on the new front end machine C1SUS.

We put some printk commands in an initialization code like Yoichi did (see this entry) to confirm if the initialization of the BOs properly happens or not.

Then we found that we had to put the BO modules also in an IOP model file which controls all the ADCs and the DACs.

We put the BO modules in the IOP file and then BOs started being recognized by the IOP, however they still are not fully recognized by the realtime control process.

We continue this work...

 

[Some notes]


[front end code]

First of all we looked at the front end c-code c1sus.c living under /cvs/cds/calech/cds/advLigoRTS/src/fe/c1sus/.

It was okay because there was a proper BO statement like

CDS_CARDS cards_used[] = { {CON_32DO,0}, {CON_32DO,2}};

 

[initialization code]

 There is an initialization code called map.c living under /cvs/cds/calech/cds/advLigoRTS/src/fe.

This code is complied when we do the make commands as described on the wiki.

Eventually the initialization code is executed only when the IOP starts up. This happens when we type startc1x02 at /cvs/cds/rtcs/caltech/c1/script/.

 

[printk statments]

   We made a backup file named map_20100830.c.back for map.c. Then we added to map.c some pintk statements in a while loop which looks for available BOs.   

After running the make commands for the IOP file and startc1x02, we basically can check the results of those printk statements by using dmesg.

We found that map.c was running correctly because  map.c went in the while loop 4 times which is exactly the same number as the BOs we put in the model file.

However the code failed to install the BOs each time.

 

[BO modules in IOP file]

  Joe pointed out the failure in map.c was caused by lack of the BO modules in the IOP file c1x02.mdl.

Indeed putting the BO modules in the IOP fixed the problem. 

Another thing we found at this time is that there is a maximum number of BOs we can put in a model file.

The maximum number is 4, which is not enough for us because we need to put 5 of them including a 16bit BIO and four 32bit BOs.

Now Joe is asking to Alex about this issue.

Anyway now the IOP can recognize the BO cards, this fact can be found if you look at the log file /cvs/cds/rtcds/caltech/c1/target/c1x02/logs/log.txt.

The log file saids "3 Contec 32ch PCIe DO cards found", which is a good sign. 

 

[BO modules in realtime code] 

Although the IOP started seeing the BO cards, the realtime code c1sus still didn't fully recognize the BO cards.

If we look at the log file log.txt at /cvs/cds/rtcds/caltech/c1/target/c1sus/logs/, there is an evidence that the code found some cards.

The log file saids  

   Model 6 = 10

   Model 7 = 4

   Model 8 = 4

   Model 9 = 4

   Model 10 = 0.

 It looks like these corresponds to the BO cards.

So the code found some cards, but doesn't know what they are.

We need few more debugging for the BOs... 

  6616   Mon May 7 21:05:38 2012 DenUpdateCDSbiquad filter form

I wanted to switch the implementation of IIR_FILTER from DIRECT FORM II to BIQUAD form in C1IOO and C1SUS models. I modified RCG file /opt/rtcds/rtscore/release/src/fe/controller.c by adding #define CORE_BIQUAD line:

#ifdef OVERSAMPLE
#define CORE_BIQUAD      
#if defined(CORE_BIQUAD)

C1IOO model compiled, installed and is running now. C1SUS model compiled, but during installation I've got an error:

controls@c1sus ~ 0$ rtcds install c1sus


Installing system=c1sus site=caltech ifo=C1,c1
Installing /opt/rtcds/caltech/c1/chans/C1SUS.txt
Installing /opt/rtcds/caltech/c1/target/c1sus/c1susepics
Installing /opt/rtcds/caltech/c1/target/c1sus
Installing start and stop scripts
/opt/rtcds/caltech/c1/scripts/killc1sus
Performing install-daq
Updating testpoint.par config file
/opt/rtcds/caltech/c1/target/gds/param/testpoint.par
/opt/rtcds/rtscore/branches/branch-2.5/src/epics/util/updateTestpointPar.pl -par_file=/opt/rtcds/caltech/c1/target/gds/param/archive/testpoint_120507_205359.par -gds_node=21 -site_letter=C -system=c1sus -host=c1sus
Installing GDS node 21 configuration file
/opt/rtcds/caltech/c1/target/gds/param/tpchn_c1sus.par
Installing auto-generated DAQ configuration file
/opt/rtcds/caltech/c1/chans/daq/C1SUS.ini
Installing EDCU ini file
/opt/rtcds/caltech/c1/chans/daq/C1EDCU_SUS.ini
Installing Epics MEDM screens
Running post-build script

ERROR: Could not find file: test.py
Searched path: :/opt/rtcds/userapps/release/cds/c1/scripts:/opt/rtcds/userapps/release/cds/common/scripts:/opt/rtcds/userapps/release/isc/c1/scripts:/opt/rtcds/userapps/release/isc/common/scripts:/opt/rtcds/userapps/release/sus/c1/scripts:/opt/rtcds/userapps/release/sus/common/scripts:/opt/rtcds/userapps/release/psl/c1/scripts:/opt/rtcds/userapps/release/psl/common/scripts
Exiting
make: *** [install-c1sus] Error 1

Jamie, what is this test.py?

  6622   Tue May 8 09:47:53 2012 JamieUpdateCDSbiquad filter form

Quote:

I wanted to switch the implementation of IIR_FILTER from DIRECT FORM II to BIQUAD form in C1IOO and C1SUS models. I modified RCG file /opt/rtcds/rtscore/release/src/fe/controller.c by adding #define CORE_BIQUAD line:

#ifdef OVERSAMPLE
#define CORE_BIQUAD      
#if defined(CORE_BIQUAD)

 I am really not ok with anyone modifying controller.c.  If we're going to be messing around with that we need to change procedure significantly.  This is the code that runs all the models, and we don't currently have any way to track changes in the code.

Did you change it back?  If not, do so immediately and stop messing with it.  Please consult with us first before embarking on these kinds of severe changes to our code.  This is the kind of shit that other people have done that has bit us in the ass in the past.

Futhermore, there is already a way to enable biquad filters in the new version with out modifying the RCG source.  All you need to do is set biquad=1 in the cdsParameters block for you model.

DO NOT MESS WITH CONTROLLER.C!

  6624   Tue May 8 10:43:42 2012 DenUpdateCDSbiquad filter form

Quote:

Quote:

I wanted to switch the implementation of IIR_FILTER from DIRECT FORM II to BIQUAD form in C1IOO and C1SUS models. I modified RCG file /opt/rtcds/rtscore/release/src/fe/controller.c by adding #define CORE_BIQUAD line:

#ifdef OVERSAMPLE
#define CORE_BIQUAD      
#if defined(CORE_BIQUAD)

 I am really not ok with anyone modifying controller.c.  If we're going to be messing around with that we need to change procedure significantly.  This is the code that runs all the models, and we don't currently have any way to track changes in the code.

Did you change it back?  If not, do so immediately and stop messing with it.  Please consult with us first before embarking on these kinds of severe changes to our code.  This is the kind of shit that other people have done that has bit us in the ass in the past.

Futhermore, there is already a way to enable biquad filters in the new version with out modifying the RCG source.  All you need to do is set biquad=1 in the cdsParameters block for you model.

DO NOT MESS WITH CONTROLLER.C!

 ok

  7041   Thu Jul 26 17:39:49 2012 DenUpdatedigital noisebiquad key is working

 I've filtered a 1 Hz sin wave excitation with a notch filter inside c1sus and c1rfm models. The biquad key is switched on in the last one, c1sus uses DF2. The results are indeed different.

df2_bqf.png    df2_bqf_spec.png

Still I do not like huge (2n+1) harmonics in the output of the biquad filter, I do not get them in the simulations. They are absent in the time series as well. So this is not a psd-estimation effect.

iir_time_notch.pngiir_psd_notch.png

 

  7045   Fri Jul 27 14:30:49 2012 JamieUpdatedigital noisebiquad key is working

What is "DQF"?  Is that the biquad?  And what is the difference between DF1 and DF2?  Why don't you just write out the name, so it's more clear.

  7050   Mon Jul 30 14:24:25 2012 DenUpdatedigital noisebiquad key is working

Quote:

What is "DQF"?  Is that the biquad?  And what is the difference between DF1 and DF2?  Why don't you just write out the name, so it's more clear.

DQF - biquad form
DF1 - direct form 1
DF2 - direct form 2
LNF - low-noise form
 
The difference between them is described in Matt's slides G0900928-v1. I think, LNF coefficients are incorrect in the presentation
 
lnf.png
  6748   Sun Jun 3 23:50:00 2012 DenUpdateCDSbiquad=1

From now all models calculate iir filters using biquad form. I've added biquad=1 to cdsParameters to all models except c1cal, built, installed and restarted them.

  4597   Mon May 2 13:43:05 2011 steveFrogsPhotosbirthday boys

.....Happy.... Birthday.... to.... Joseph... and... Jamie...Happy....Birthday..... to.... You............sing with us........Happy Birthday.....to you

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