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ID Date Author Typedown Category Subject
  4291   Mon Feb 14 18:27:39 2011 josephbUpdateCDSBegan updating to latest CDS svn, reverted to previous state

[Joe, Alex]

This morning I began the process of bringing our copy of the CDS code up to date to the version installed at Livingston. The motivation was to get fixes to various parts, among others such as the oscillator part.   This would mean cleaning up front end model .mdl files without having to pass clk, sin, cos channels for every optic through 3 layers of simulink boxes.

I also began the process of using a similar startup method, which involved creating /etc/init.d/ start and stop scripts for the various processes which get run on the front ends, including awgtpman and mx_streams.  This allows the monitor software called monit to remotely restart those processes or provide a web page with a real time status of those processes.  A cleaner rc.local file utilizing sub-scripts was also adapted.

I did some testing of the new codes on c1iscey.  This testing showed a problem with the timing part of the code, with cycles going very long.  We think it has something to do with the code not accounting for the fact that we do not have IRIG-B timing cards in the IO chassis providing GPS time, which the sites do have.  We rely on the computer clock and ntpd.

At the moment, we've reverted to svn revision 2174 of the CDS code, and I've put the previously working version of the c1scy and c1x05 (running on the c1iscey computer) back. Its from the /opt/rtcds/caltech/c1/target/c1x05/c1x05_11014_163146 directory.  I've put the old rc.local file back in /diskless/root/etc/ directory on the fb machine.  Currently running code on the other front end computers was not touched.

  4292   Mon Feb 14 21:59:35 2011 ranaUpdateCDSUpdated some DAQ channel names

Although Joe and Kiwamu claim that they have inserted the correct DAQ names for the OPLEVs (e.g. PERROR and YERROR) back in Jan. 11, when I look today, I see that these channels are missing!

I want my PERROR/YERRORs back!

 

  4295   Tue Feb 15 03:10:37 2011 kiwamuUpdateASCIR beam alignment for Xarm : TRX reduction

I tried aligning the IR beam axis for the X arm to have good beam centering on ITMX and ETMX.

As a first attempt, I started translating the beam upward by steering PZT1 and PZT2, since the pitch was quite off from the center on ITMX.

As a result I could decrease the pitch off-centering down to about 0.5 mm on ITMY, but on the other hand TRX decreased a lot (by a factor of 4).

I am worrying if something in the central part of IFO might be clipping the beam.

 


(notes)

When I was touching PZT1 and PZT2, I payed attention on IP_ANG so that I don't lose a beam spot on IP_ANG.

As long as the beam is on the IP_ANG QPD, the angle of the beam should not be so much different.

Each time after I touched the PZTs, I realigned ITMX and ETMX to maximize the transmitted light.

In this way I proceeded the alignment by changing the PZT offsets little by little while keeping the X arm locked always.

At the beginning, all the PZT offsets were zero. And at the end of this work they became:

 C1:LSC-PZT1_Y = 1.880

 C1:LSC-PZT2_Y = -1.699

But during this alignment work TRX gradually decreased eventually down to 0.25, which had been 1 at the beginning (TRX is calibrated by dividing it by its maximum power).

Along with this TRX reduction, I found that the optical gain also decreased by a factor of about 5.

This fact has been confirmed by intentionally increasing the filter gain such that the servo oscillates at the UGF.
 

Quote:

The amounts of the X arm's beam off-centering have been measured by the A2L technique.

     - ETMX

         PIT  = -1.61 mm

         YAW =  -0.918 mm

    - ITMX

         PIT = -3.76 mm

        YAW = -2.24 mm

 

  4296   Tue Feb 15 06:15:07 2011 SureshUpdateASCno signal from IP_ANG_Seg1

[Valery, kiwamu, Jenne, Suresh]

    I first interchanged the two QPD's on the Y end table to see if the problem QPD related.  Exchanging the units did not make any difference.  The problem therefore had to be in the cables or the circuit boards in 1X4

    We traced the signals pertaining to the IP_ANG QPD ( "Initial Pointing Beam") using  Jay's wiring diagram (pages 2 and 5 of 7).  We noted that while the signals were available on all Segments till the Monitors (Lemo) on 1X4-2-2A card, two of the lines did not reach the output of the cross connect 1X4-B8.  We checked card to make sure that the signals were indeed reaching the back plane of the 1X4-2 chassis using a D990612 extension board.  The card was found to be okay.  We therefore suspected that the cable (CAB_1X4_?) going from the card to the cross connect 1X4-B8 was faulty.  Indeed visual inspection showed that the crimping of the connector was poor and weight of the cable had put further strain on the crimping.  

   I changed the 64-pin connector on the 1X3-2-2A side of the cable. 

When I connected everything back together the problems persisted. Namely the lines P1-1A  (Segment 1 high) and P1-2C (Segment 2 Low) were floating They were not reaching points 2T and 3T respectively on the output of the cross connect.

   I therefore replaced 1X4-B8 with a similar unit which I found in one of the shelves along the East (Y) arm. 

I then checked with the StripTool to make sure that all the quadrants are showing similar response to a flashlight on the QPD.   All Segments are working fine now. Currently the IR Initial Pointing beam reaches the QPD but is not centered on it. 

I did not attempt to center it since the beam appeared to be clipped and may anyway require repositioning.

JD: We need to meditate on where this beam could be getting clipped.  Suresh and I checked that it's not on the viewport on the beam's way out of the ETMY chamber by seeing that the beam is far away from the edges of the viewport, and also far away from the edges of the black beamtube between the viewport and the table.  Suresh mentioned that the clipping nature of the IP_ANG beam sometimes goes away.  I don't know if this is the same clipping that Kiwamu might be seeing with the main beam, or if this is separate clipping just with the IP beam, after it's been picked off.  I suspect it's the same as what Kiwamu is seeing....maybe when we move PZT1, we clip on one of the MMT mirrors or PZT2??  If this is true, it's a total pain since we might have to vent if we can't steer around it.

Y-end_beam.JPG

 

  4298   Tue Feb 15 11:43:53 2011 JenneUpdateComputersOccasional error with NDS2

Just in case anyone has encountered this / knows how to fix it....

I'm running NDS2 on Rossa, trying to get a bunch of raw data from S5.  I get 10min of data at a time, and it goes through ~200 iterations successfully, and then throws the following error:

Getting new data
Connecting.... authenticate ... done
daq_recv_id: Wrong length read (0)
Error reading writerID in daq_recv_block
Warning: daq_request_data failed
 
??? Error using ==> NDS2_GetData
Fatal Error getting channel data.

Error in ==> getDARMdataTS at 37
oot = NDS2_GetData({...

Error in ==> SaveRawData_H1_DARM at 40
    oot = getDARMdataTS(t0s(ii), strideDuration, srate);

  4300   Tue Feb 15 11:56:17 2011 josephbUpdateCDSUpdated some DAQ channel names
That is my fault for not running the activateDAQ.py script after a round of rebuilds. I have run the script this morning, and confirmed that the oplev channels are showing up in dataviewer.

Quote:

Although Joe and Kiwamu claim that they have inserted the correct DAQ names for the OPLEVs (e.g. PERROR and YERROR) back in Jan. 11, when I look today, I see that these channels are missing!

I want my PERROR/YERRORs back!

 

 

  4302   Tue Feb 15 15:06:25 2011 josephbUpdateCDSCDS todo list for tomorrow morning

Currently, there is a test directory called /opt/rtcds/caltech/c1/new_core where we have the latest svn checkout.  Tomorrow (after everything works), it will become the core directory.

1) Modify on the fb machine the /diskless/root/etc/ld.so.cache file.  This is done by logging into fb, going to /etc/ld.so.conf.d/, modifying epics-x86_64.conf to only have .10 stuff , and running sudo /sbin/ldconfig.  Copy the newly generated /etc/ld.so.cache file to /diskless/root/etc/.

2) Modify the rc.local file on the fb machine in /diskless/root/etc/ to take advantage of the new subscripts and init.d/ start scripts.

3) Add the no_rfm_dma to all the iop models (c1x01,c1x02,c1x03,c1x04,c1x05).

4) Rebuild all front end models with new code.  Install.

5) Build awgtpman and mx_streams with new code.

6) Rerun activateDaq.py (to fix channel names from all the rebuilt code).

7) Double check Burt request files have the switch fix.

8) Restart the front ends.

9)Restart the frame builder.

9) Check channels, exitations, RFM connections.

10) Check Monit is working.

  4303   Tue Feb 15 17:48:22 2011 JenneUpdateIOOMode Cleaner resonating again

[Valera, Jenne]

After Steve and Valera switched out the PMC, the Mode Cleaner resonance needed to be brought back.  We spent some time playing with the 2 steering mirrors directly after the PMC, to get the beam through the EOM, and to achieve flashing in the MC.  Valera then adjusted those 2 steering mirrors to minimize MC_REFL_DC.  I did a little bit more, and it's kind of close now, but we're only at ~half normal transmitted power.  Since the 2 steering mirrors after the PMC are so close together, the beam alignment is pretty sensitive to even small touches.  So it's probably time to move on to using the last zigzag steering mirrors on the PSL table, since they're farther apart. 

I have to head out for a little while, but I'll be back in a few hours. Kiwamu said he might continue the alignment into the MC, if he needs the IFO.  Also, we should measure the power before and after the EOM, just to confirm that we're getting through it optimally.  The beam looks good after the EOM, and the MC is resonating, so it should be fine, but it can't hurt to check.

  4304   Tue Feb 15 21:45:08 2011 ranaUpdateIOOThe MC TRANS Story

I forgot to elog that last night I touched up the MC2_TRANS QPD setup. I was perplexed by it always going out of alignment so I investigated.

I found that the fork clamp for the steering mirror for the QPD was not tightened. Shame. The beam diameter was equal to the aperture of the QPD and was clipping. Double shame.

I added a lens and tightened the mounts and centered the beam at ~9 PM yesterday. You can see in the attached trend that the measured power went up by ~10%.

Later, there's a big gap where Valera and Steve change out the PMC. You can see that the MC REFL voltage goes from 4.5 V to 5 V (10% increase in the power delivered to the MC).

There's essentially no change in the total transmission - this indicates that although the PMC transmission is now higher by ~10%, the matching to the IMC has been degraded by an equivalent fraction.

Needs some mode matching work.

Attachment 1: a.png
a.png
  4305   Wed Feb 16 01:03:59 2011 JenneUpdateIOOMC alignment work

So.... Kiwamu and I were concerned (still a little concerned) that ETMY is not damping as nicely as it should be.  (It's fine, but the UL rms is ~5, rather than ~1 or less. BURT restores by Kiwamu didn't change anything.) Anyhow, I was heading out to push the annoying ribbon cables more firmly into the satellite adapter board things that are tied to the racks in various places (The back of 1X5 for the corner optics and the end station racks for the ETMs).  The point was to push in the ETMY one, but while I was out in the lab and thinking about it, I also gave all of the corner connectors (MC1, MC2, MC3, ITMx, ITMY, BS, PRM, SRM) a firm push. 

Kiwamu noticed that when I did this, the Mode Cleaner alignment got a little bit worse, as if the connection to the satellite adapter boards hadn't been great, I pushed the connectors in and the connection got better, but we also got a bit of a DC offset in the MC alignment.  Anyhow, the MC_TRANS power went down by ~2, to about the place it had been before Kiwamu adjusted the position of the lens in between the zigzag mirrors.  (I don't know if Kiwamu elogged it earlier, but he scooted the lens a teensy bit closer in the optical path to the Mode Cleaner). 

To counteract this loss in MC transmitted power as a result of my connector actions, I went back to the PSL table and fiddled with the zigzag steering mirrors that steer the beam from the PSL table over to the mode cleaner.  I got it a little better, but it's still not perfect.

Kiwamu has noted that to improve the mode matching into the Mode Cleaner with the new PMC in place, we might have to move the lens which is currently between the zigzag steering mirrors, and put it after the second mirror (so in between the last steering mirror and the pickoff window that sends a piece of the beam over to PSL_POS and PSL_ANG).  This will make the waist between MC1 and MC3 tighter. 

Moral of the story:  To improve IMC mode matching we need to move the last lens closer in the optical path to the mode cleaner waist. Twiddle with zigzag steering mirrors to optimize.

  4306   Wed Feb 16 02:04:11 2011 kiwamuUpdateASCIR beam alignment

[Jenne and Kiwamu]

 This time we aligned the vertical angle (not the translation) of the IR beam so that the transmitted light from BS shoots the center of ETMY.

The idea is to use ETMY as a beam pointing reference instead using IP_ANG, assuming the translation is not so bad.

As a result it looks like we are wining. A quick A2L test on ITMX_PITCH showed a small off-centering at sub-milimeter level.

 

 We are concluding that the initial beam after PZT2 had been pointing downward somehow.

Before doing this whole job, we checked the spot shape on IP_POS to see if the beam is clipped or not. It was a round shape, which means no clipping around MMT.

But on the other hand, the spot on IP_ANG had been clipped more than half of its bottom as Suresh reported on his elog (see here).

I found that this clipping is able to be fixed by moving the beam angle upward. I guess the clipping happened at one of the steering mirror in the ETMY chamber.

According to these information, we imagined that the beam was somehow pointing downward after PZT2.

So we started aligning the beam by touching only PZT2 for vertical direction. Then we found a beam spot on ETMY's suspension frame, and brought it to the center.

Then we aligned BS and X arm for this new beam axis. The it resulted a small off-centering on pitch.

Once the MC fully gets back, we will examine the TRX degradation with this configuration.

  4307   Wed Feb 16 10:35:40 2011 Larisa ThorneUpdateIOOWFS quantum efficiency as a function of angle

 Here is the followup on Jenne's February 14th, 2011 update on the quantum efficiency measurements of WFS2.

http://nodus.ligo.caltech.edu:8080/40m/4289

 

Attached is a PDF of my calculations, based on measurements ranging between 0-25 degrees in 5 degree increments.

The graph at the bottom plots these angles versus the calculated quantum efficiency at each point and the responsivity. Since quantum efficiency and responsivity only differ by a factor of some natural constants (lamda, e, h, c), I used a graph with two vertical axes, because the points would be plotted at essentially the same location if quantum efficiency (%)  and responsivity (Amps/Watts) were graphed on two separate plots.

The calculated values for quantum efficiency based on my measurements (labelled "ExpAverage") were pretty close to what Jenne had calculated in earlier attempts, which was around 60%. Just to test, I compared my quantum efficiency result against the calculation of quantum efficiency using the responsivity value for silicon, 0.5 Amps/Watt, which is labelled as "Spec". Comparison of "ExpAverage" and "Spec" shows that they differ by only about 2%, so I conclude that the theoretical quantum efficiency calculated using a given responsivity agrees with my measurement-based experimental result.

Attachment 1: QEcalcs.pdf
QEcalcs.pdf
  4308   Wed Feb 16 12:16:14 2011 josephbUpdateCDSFixed Optical level SUM channel names

[Joe,Valera]

Valera pointed out the OPLEV SUM channels were incorrect.  We changing the optical level sum channel to _OPLEV_SUM when it should have been OL_SUM.  This has been fixed in the activateDAQ.py script.

  4309   Wed Feb 16 23:54:34 2011 ranaUpdateCDSToday's CDS problems
  1. ETMX cannot load his filter coefficients. Even if I change the file, the load button doesn't work. I tried changing the lockin filters but they won't load.
  2. The ETMX filter modules appear to have 2048 for some of the modules and 16384 for some of the others. How come the make script doesn't make them all 16384?
  3. There are a bunch of kill/start scripts in the scripts/ directory instead of in the scripts/FE/ directory. Did this get reverted after a new code exchange?
  4. I tried restarting the code using c1startscx, but that doesn't work correctly. It cannot find the burtrb and burtwb files even though they are in the normal path.
  5. Kiwamu was using a bunch of cockamamie filters I found.
  6. I can't get any minute trend data. I tried on rossa, rosalba, and op440m.
MC damp dataviewer diaggui AWG c1lsc c1ioo c1sus c1iscex c1iscey RFM The Dolphins Sim.Plant Frame builder TDS Cabling
                             
  4311   Thu Feb 17 11:20:04 2011 josephbUpdateCDSstart scripts no longer need sudo

I've modified the rc.local file to run the IOC codes as controls, which means they no longer write root permission log files on startup.

The awgtpman, which was the other permission issue with the start scripts, is started by a run script now.  This new version seems to be content to keep the permissions of the current log file, which is set to controls.

This should prevent the issue of sudo wiping your path environment variable for just that command. (Try "sudo which burtwb" versus "which burtwb" for example).  This apparently a security feature of sudo.

If you should happen to use sudo to run a start script, the easiest solution to fix the permissions is just got to the target directory (type "target") and run "sudo chown controls:controls -R *" on one of the workstations (the front ends don't handle the groups properly at the moment).

This should allow the scripts to properly use burtrb and burtwb to write and backup burt files.

  4312   Thu Feb 17 11:49:48 2011 josephbUpdateCDSFront end start/stop scripts go to /scripts/FE again

I modified the core/advLigoRTS/Makefile to once again place the startc1SYS and killc1SYS scripts in the scripts/FE/ directory.

It had been reverted in the SVN update.

  4313   Thu Feb 17 11:51:14 2011 josephbUpdateCDSLockin filter names too long - broke loading

Problem:

Could not load filters into the C1:SUS-ETMX_LOCKIN1_SIG filter bank.

Reason:

Apparently the filter bank name was too long.  I'm not sure why this isn't caught by the real time code generator, I'm planning on asking Alex and Rolf about it today.

Solution:

Reduce the name of the components.  Basically LOCKIN1 needs to become something like LOCK1 or LIN1.

 

In related news, it looks like the initial filters are hard coded to be 2048 Hz.  Given that they start out empty they won't cause things to break immediately, and if you're editing the file you can update the rate as you add the filter.  I'll also bring this up with Alex and Rolf and see if the RCG can't be more intelligent about its filter generation.

 

  4314   Thu Feb 17 13:20:06 2011 SureshUpdateVIDEOSome more labels

[Larisa, Kiwamu, Steve and Suresh]

 

  We continued the labeling of video cables. All exiting cables which are going to be used used in the new scheme have been labeled.

We also labeled the cables running from the video mux to the TV monitors in the computer room. Some of these will be removed or reallocated.

We will continue next Wednesday (after the meeting) and will lay cables that are most urgently required. 

 i

  4315   Thu Feb 17 14:17:27 2011 SureshUpdateElectronicsRF Distribution box and REFL11

 

The Distribution box is several steps nearer to completion.

 

1) Soldered capacitors and DC power lines for four units of the distribution box.

2) mounted all the components in their respective places.

3) Tomorrow we prepare the RF cables and that is the last step of the mechanical assembly. 

4) we plan to test both the generator and distributon parts together.

 

 

 

REFL 11

 

[Kevin, Suresh]

Kevin took a transfer function of the newly assembled PD and noticed that the frequency has shifted to 14.99  freom 11. MHz.

We needed to find the current RLC combination.  So we  removed the ferrite core from L5 rendiring it to its aircore value of  0.96/muH. We then used this to find the Capacitance of the PD (117pF)

We  used this value to compute the inductance required to achieve 11.065MHz  which turned out to be 1.75microH.

This was not reachable with the current L5 which is of the type  143-20J12L (nominal H=1.4 micro Henry).

We therefore changed the inductor to SLOT 10 -3-03. It is a ferrite core, shielded inductor with a plasitc sleeve. Its nomial valie is 1.75 microH

We then tested the DC output to see if here is a response to light. There was nonel. l

The problem was traced to the new inductor.  Surprisingly the inductor coil had lost contact with the pins.

I then replacd the inductor and checked again.  The elecronics seems to work okay..   but there is a very small signal 0.8mV for 500microW. 

There seems to be still something wrong with the PD or its electronics.

 

 

  4316   Thu Feb 17 14:52:27 2011 JenneUpdateIOOMC alignment work

I worked a little bit more on optimizing the mode matching to the MC, but it's still not great.  I've only gotten a visibility of ~45%, but Koji said that it used to be ~87%.  So there is a long way to go.  Kiwamu said he can work with the lower-power configuration for a few days, and so my next step will be to measure the beam profile (stick a window in the path, and look at the refl from the window....that way we don't get thermal lensing from transmission through an optic), and redo the mode matching calculation, to figure out where the last lens should actually sit.

Quote:

So.... Kiwamu and I were concerned (still a little concerned) that ETMY is not damping as nicely as it should be.  (It's fine, but the UL rms is ~5, rather than ~1 or less. BURT restores by Kiwamu didn't change anything.) Anyhow, I was heading out to push the annoying ribbon cables more firmly into the satellite adapter board things that are tied to the racks in various places (The back of 1X5 for the corner optics and the end station racks for the ETMs).  The point was to push in the ETMY one, but while I was out in the lab and thinking about it, I also gave all of the corner connectors (MC1, MC2, MC3, ITMx, ITMY, BS, PRM, SRM) a firm push. 

Kiwamu noticed that when I did this, the Mode Cleaner alignment got a little bit worse, as if the connection to the satellite adapter boards hadn't been great, I pushed the connectors in and the connection got better, but we also got a bit of a DC offset in the MC alignment.  Anyhow, the MC_TRANS power went down by ~2, to about the place it had been before Kiwamu adjusted the position of the lens in between the zigzag mirrors.  (I don't know if Kiwamu elogged it earlier, but he scooted the lens a teensy bit closer in the optical path to the Mode Cleaner). 

To counteract this loss in MC transmitted power as a result of my connector actions, I went back to the PSL table and fiddled with the zigzag steering mirrors that steer the beam from the PSL table over to the mode cleaner.  I got it a little better, but it's still not perfect.

Kiwamu has noted that to improve the mode matching into the Mode Cleaner with the new PMC in place, we might have to move the lens which is currently between the zigzag steering mirrors, and put it after the second mirror (so in between the last steering mirror and the pickoff window that sends a piece of the beam over to PSL_POS and PSL_ANG).  This will make the waist between MC1 and MC3 tighter. 

Moral of the story:  To improve IMC mode matching we need to move the last lens closer in the optical path to the mode cleaner waist. Twiddle with zigzag steering mirrors to optimize.

 

  4318   Thu Feb 17 23:11:40 2011 ranaUpdateElectronicsVCO Frequency Noise Measurement with the MFD

This is the 140 ft. MFD measurement of the VCO phase noise. It is open loop and so should be a good measurement. The RMS is 30 Hz integrated down to 2 mHz.

I don't know why this doesn't agree with Suresh's measurements of the same thing which uses the PLL feedback method.

In BLUE, I also plot the frequency noise measured by using a Stanford DS345 30 MHz func. generator. I think that this is actually the noise of the FD (i.e. the SR560 preamp) and not the DS345. Mainly, it just tells you that the PINK VCO noise measurement is a real measurement.

I calibrated it by putting in a 5 kHz_pp triangle wave on the sweep of the DS345 and counting the counts in DV.

Attachment 1: vco.png
vco.png
  4320   Thu Feb 17 23:56:53 2011 josephbUpdateCDSDaqd was rebuilt, now reverted.

As one of the trouble shooting steps for the daqd (i.e. framebuilder) I rebuilt the daqd executable.  My guess is somewhere in the build code is some kind of GPS offset to make the time correct due to our lack of IRIG-B signal.

The actual daqdrc file was left untouched when I did the new install, so the symmetricom gps offset is still the same, which confuses me.

I'll take a look at the SVN diffs tomorrow to see what changed in that code that could cause a 300000000 or so offset to the GPS time.

 

 

  4321   Fri Feb 18 00:13:55 2011 kiwamuUpdateCDSRe:Daqd was rebuilt, now reverted.

THANK YOU, JOE !!! 

Quote:

As one of the trouble shooting steps for the daqd (i.e. framebuilder) I rebuilt the daqd executable.

  4323   Fri Feb 18 13:41:22 2011 josephbUpdateCDSCDS fixes

I talked to Alex today and had two things fixed:

First the maximum length of filter names (in the foton C1SYS.txt files in /chans) has been increased to 40, from 20.  This does not increase EPICS channel name length (which is longer than 20 anyways).

This should prevent running into the case where the model doesn't complain when compiled, but we can't load filters.

Additionally, we modified the feCodeGen.pl script in /opt/rtcds/caltech/c1/core/advLigoRTS/src/epics/util/ to correctly generate names for filters in all cases.  There was a problem where the C1 was being left off the file name when in the simulink .mdl file the filter was located in a box which had "top_names"  set.

  4324   Fri Feb 18 15:05:49 2011 kiwamuUpdateGreen Lockingtransfer function of angle to beat note (length)

[Koji and Kiwamu]

 We took transfer functions (TF) from the angle excitations at ETMX and ITMX to the green beat note signal (i.e. angle to length TF).

It turned out that the coupling from ETMX_PIT is quite large.

I wonder how f2p of the ETMX changes this coupling. We'll see.

 

a2l_TF.png

 

The plot above shows a set of the transfer functions from the angle excitation to the green beat note.

Note that the y-axis has not been calibrated, it is just a unit of counts/counts.

You can see that the TF from ETMX_PIT to the beat (red cruve) is larger than the others by about a factor of 10 over most of the frequency range.

This means that any PIT motions on ETMX can be coupled into the green beat signal somewhat over the wide frequency range.

It looks having a resonance at 1.5 Hz, but we don't exactly know why.

At that time the coil gains on only ITMX were tuned by applying f2p filters, but ETMX wasn't because of a technical reason coming from epics.

 

- - - - measurement conditions

  * PSL laser was locked to X arm by feeding back the IR PDH signal to MC2.

  * the green laser was locked to Xarm as usual.

  * took the green beat note signal (approximately 0 dBm) into Rana's MFD with the cable length of about  6 m.

  * the output from the MFD was connected to XARM_COARSE channel without a whitening filter.

  * excitation signal was injected into either ASC_PIT or ASC_YAW. The excitation was Gaussian noise with frequency band of 10 Hz and amplitude of 300 counts.

  * only ITMY had the f2p filters, which balance the coil gains all over the frequency.

 

  4325   Fri Feb 18 17:52:25 2011 josephb, valeraUpdateCDSc1ass updated

We updated the c1ass model to include the BS.  We removed the dither excitation of the PZTs.  PZT control goes to epics. To do this, modified the /cvs/cds/caltech/target/c1iscaux/PZT_AI.db file.  We basically have it sum both the existing epics slider and our new output from c1ass.

More importantly we updated the color scheme.

We compiled and tested the Dolphin and RFM which work.

I should note we can't figure out why testpoints are not working properly with just this model.  Alex and Joe spent well over an hour trying to debug it to no success.  Current workaround is to add what channels you want from c1ass to the DAQ recording.  Other testpoints on other models appear to be working.

Attachment 1: c1ass_updated.png
c1ass_updated.png
  4330   Sat Feb 19 05:25:20 2011 SureshUpdateElectronicsRF: Distribution box

Most of the RF cables required for the box are done.   There are two remaining and we will attend to these tonight. 

We expect to have finished the mechanical assembly by Sunday and start a quality test on Monday.

 

 

  4332   Mon Feb 21 11:05:51 2011 ZachUpdateelogrestarted

 I restarted the elog using the script.

  4336   Tue Feb 22 00:41:34 2011 SureshUpdateElectronicsRF Distribution box: assembly completed

The mechanical assembly of RF distribution box is 99% complete.  Some of the components may be bolted to the teflon base plate if needed. 

All RF cables and DC voltage supply lines have been installed and tested.  I removed the terminal block which was acting as a distribution box for the common zero voltage line.  Instead I have used the threaded holes in the body of each voltage regulator.   This allows us to keep the supply lines twisted right up to the regulator and keeps the wiring neater.  The three regulator bodies have been wired together to provide a common zero potential point. 

I did a preliminary test to see if everything is functioning. All units are functioning well.  The output power levels may need to be adjusted by changing the attenuators. 

The 2x frequency multiplier outputs are not neat sine waves.  They seem to produce some harmonics, unlike the rest of the components.

I will post the measured power output at each point tomorrow.  The RF power meter could not be found in the 40m lab.  We suspect that it has found its way back to the PSL lab.

 

  4337   Tue Feb 22 11:53:38 2011 steveUpdateElectronicsRF Distribution box: assembly completed

Quote:

The mechanical assembly of RF distribution box is 99% complete.  Some of the components may be bolted to the teflon base plate if needed. 

All RF cables and DC voltage supply lines have been installed and tested.  I removed the terminal block which was acting as a distribution box for the common zero voltage line.  Instead I have used the threaded holes in the body of each voltage regulator.   This allows us to keep the supply lines twisted right up to the regulator and keeps the wiring neater.  The three regulator bodies have been wired together to provide a common zero potential point. 

I did a preliminary test to see if everything is functioning. All units are functioning well.  The output power levels may need to be adjusted by changing the attenuators. 

The 2x frequency multiplier outputs are not neat sine waves.  They seem to produce some harmonics, unlike the rest of the components.

I will post the measured power output at each point tomorrow.  The RF power meter could not be found in the 40m lab.  We suspect that it has found its way back to the PSL lab.

 

 http://www.timesmicrowave.com/wireless/index.shtml  

Frank is recommending these PhaseTrack-210 as phase stable low loss rf coax cables.

  4338   Tue Feb 22 14:37:24 2011 steveUpdateSAFETYLarisa received 40m safety training

Larisa Thorne received 40m lab specific, basic safety training. She will attend P. King's Basic Laser Safety Training Session tomorrow.

 

  4339   Tue Feb 22 23:11:42 2011 valeraUpdate new medm screens: C1ASS.adl and C1MCASS.adl
Attachment 1: C1MCASS.jpeg
C1MCASS.jpeg
Attachment 2: C1ASS.jpeg
C1ASS.jpeg
  4340   Tue Feb 22 23:40:31 2011 KojiUpdateIOOMC mode mach improvement

As per Kiwamu's request I made a light touch to the input steering and the mode matching lens.

Here V_ref and V_trans are C1:IOO-MC_RFPD_DCMON and C1:IOO-MC_TRANS_SUM, respectively.

Result: Visibility = 1 - V_ref(resonant) / V_ref(anti_reso) = 1 - 0.74 / 5.05 = 85%

What has been done:

  • Alignment of the steering mirrors before and after the last mode matching lens
       V_ref: 2.7 ==> 2.2, V_trans: 34000 ==> 39000
  • Moving of the last mode matching lens away from the MC (+ alignment of the steering mirrors)
       V_ref: 2.2 ==> 0.74, V_trans: 39000 ==> 55000
Attachment 1: IOO_MMT_110222.png
IOO_MMT_110222.png
  4341   Wed Feb 23 04:56:59 2011 kiwamuUpdateGreen Lockingnoise curve update

New noise spectra of the green locking have been updated.

The plot below shows the in-loop noise spectra when the beat signal was fedback to ETMX.

The rms noise integrated from 0.1 Hz to 100 Hz went down to approximately 2 kHz.

noise_suprresion.png

The red curve was taken when the beat was controlled only by a combination of some poles sand zeros on the digital filter banks. The UGF was at 40Hz.

This curve is basically the same as that Koji took few weeks ago (see here). Apparently the rms was dominated by the peaks at 16 Hz and 3 Hz.

The blue curve was taken when the same filter plus two resonant gain filters (at 16.5 Hz and 3.15 Hz) were applied. The UGF was also at 40Hz.

Due to the resonant gain filter at 16.5 Hz, the phase margin became less, and it started oscillating at the UGF as shown in the plot.

  4342   Wed Feb 23 08:53:58 2011 SureshUpdateElectronicsRF Distribution box: Output power levels

We wish to have roughly 2 dBm of output power on each line coming out of the RF distribution box.  So I adjusted the attenuators inside the box to get this.

I also looked at why the 2x output looked so distorted and found that the input power was around 17 dBm whereas the maximum allowed (as per the datasheet of Minicircuits MK-2) is 15dBm.  So I increased the attentuation on its input line to 5dBm (up by 2dBm)  The input power levels are around 14.6dBm now  and the distortion has come down considerably.  However the net output on the 2x lines is now down to 0.7dBm.  We will have to amplify this if we need more power.

The schematic and the power output are now like this:

RF_Distribution_box_23rdFeb.jpg


  4344   Wed Feb 23 11:53:30 2011 josephbUpdateCDSUpdated mx drivers

Alex and I updated the open mx drivers from 1.3.3 to 1.3.901 (1.4 release candidate).  We downloaded the drivers from: http://open-mx.gforge.inria.fr/

We put them in /root/open-mx-1.3.901 on the fb machine (and thus get mounted by all the front ends.).  We did configure and make and make install.

We did a quick check with /opt/mx/bin/mx_info on the fb machine at this point and realized the MAC addresses and host names were all messed up, including two listings for c1iscex with different mac addresses (neither of which was c1iscex).

We then brought all the front ends mx_streams down, brought the fb down, then cleared all the peer names with mx_hostname.  We then brought the fb up, and the front end mx_stream processes.

/opt/mx/mx_info now shows a clean and correct set of hostnames and mac addresses.  Testpoints and trends are working.

  4346   Wed Feb 23 16:56:17 2011 Larisa ThorneUpdateVIDEOCable laying...continued

Having finished labeling the existing cables to match their new names, we (Steve, Kiwamu and Larisa) moved on to start laying new cables and labeling them according to the list.

 

Newly laid cables include: ETMXT (235'), ETMX (235'), POP (110') and MC2 (105').  All were checked by connecting a camera to a monitor and checking the clarity of the resulting image. Note that these cables were only laid, so they are not plugged in.

 

The MC2 cable needs to be ~10' longer; it won't reach to where it's supposed to. It is currently still in its place. 

The three other cables were all a lot longer than necessary.

  4347   Thu Feb 24 00:54:33 2011 KevinUpdateElectronicsCalculated Dark Noise for POX and POY

[Kevin, Rana, Koji]

I calculated the dark noise of POX and POY due to Johnson noise and voltage and current noise from the MAX4107 op-amp using nominal values for the circuit components found in their data sheets. I found that the dark noise should be approximately 15.5 nV/rtHz. The measured dark noise values are 18.35 nV/rtHz and 98.5 nV/rtHz for POX and POY respectively. The shot noise plots on the wiki have been updated to show these calculated dark noise sources.

The measured dark noise for POY is too high. I will look into the cause of this large noise. It is possible that the shot noise measurement for POY was bad so I will start by redoing the measurement.

  4348   Thu Feb 24 10:56:04 2011 JenneUpdateWienerFilteringOne month of H1 S5 data is now on Rossa

Just in case anyone else wants to access it, we now have 30 days of H1 S5 DARM data sitting on Rossa's harddrive.  It's in 10min segments.  This is handy because if you want to try anything, particularly Wiener Filtering, now we don't have to wait around for the data to be fetched from elsewhere.

  4349   Thu Feb 24 11:18:08 2011 steveUpdateSUSSRM sus-cables

Cheater cables   for SRM sus tied up. They were dangling aimlessly on the floor.

Attachment 1: P1070428.JPG
P1070428.JPG
  4351   Thu Feb 24 17:42:00 2011 AidanUpdateGreen Locking15% of end laser sideband power transmitted through cavity

I did a quick calculation to determine the amount of sideband transmission through the FP cavity.

The modulation frequency of the end PDH is 216kHz. The FSR of the cavity is about 3.9MHz. So the sidebands pick up about 0.17 radians extra phase on one round trip in the cavity compared to the carrier.

The ITM reflectance is r_ITM^2 = 98.5% of power, the ETM reflection is r_ETM^2 = 95%.

So the percentage of sideband power reflected from the cavity is R_SB = r_ITM*r_ETM*(exp(i*0.17) - 1)^2 / (1 - r_ETM*r_ITM exp(i*0.17) )^2 = 0.85 = 85%

So about 15% of the sideband power is transmitted through the cavity. The ratio of the sideband and carrier amplitudes at the ETM is 0.05

So, on the vertex PD, the power of the 80MHz +/-200kHz sidebands should be around sqrt(0.15)*0.05 = 0.02 = 2% of the 80MHz beatnote.

Once we get the green and IR locked to the arm again, we're going to look for the sidebands around the beatnote.

 

 

  4352   Thu Feb 24 18:21:24 2011 kiwamuUpdateGreen Lockingin-loop and out-of-loop measurements

Two different measurement have been performed for a test of the green locking last night.

Everything is getting better. yes. yes.

green_lock_setup.png

 


[ measurement 1 : IR locking]

The X arm was locked by using the IR PDH signal as usual (#4239#4268) .

The in-loop signal at from the IR path and the out-of-loop signal at from the green beat note path were measured.

measurement1.png

Let us look at the purple curve. This is an out-of-loop measurement by looking at the green beat note fluctuation.

The rms down to 0.1 Hz used to be something like 60 kHz (see here), but now it went down to approximately 2 kHz. Good.

This rms corresponds to displacement of about 260 pm of the X arm. This is barely within the line width. The line width is about 1 nm.

 

 


[ measurement 2 : green locking]

The motion of the X arm was suppressed by using the green beat signal and feeding it back to ETMX.

After engaging the ALS servo, I brought the cavity length to the resonance by changing the feedback offset from epics.

Then took the spectra of the in-loop signal at the beat path and the out-of-loop signal at the IR PDH path.

 

 Here is a time series of TRX after I brought it to the resonance.

TRX_REFL11.png

TRX was hovering around at the maximum power, which is 144 counts.

measurement2.png

Since I put one more 10:1 filter to suppress the noise around 3 Hz, the rms of the in-loop beat spectrum went to about 1 kHz, which used to be 2 kHz (see #4341).

But the out-of-loop (IR PDH signal) showed bigger noise by a factor of 2 approximately over frequency range of from 2 Hz to 2 Hz. The resultant rms is 2.7 kHz.

The rms is primarily dominated by a peak at 22 Hz (roll mode ?).

I calibrated the IR PDH signal by taking the peak to peak signal assuming the finesse of the cavity is 450 for IR. May need a cooler calibration.

  4353   Thu Feb 24 19:59:25 2011 kiwamuUpdateGreen Lockingwhitening filter for ALS

I forgot to mention about the whitening filter for the ALS digital control system.

As usual I used a whitening filter to have a good SNR against ADC noise, but this time our whitening scheme is little bit different from the usual our systems.

I used two ADC channels for one signal and put a digital summing point  and digital filters to keep good SNR over the frequency range of interest.

It's been working fine but it's still primitive, so I will study more about how to optimize this scheme.


ACDC.png

     The diagram above shows our scheme for the signal whitening.

Basically the SNR at DC is bad when we use only a whitening filter as shown on the bottom part of the diagram because the signal is quite tiny at DC.

On the other hand if we take raw signal into ADC as 'DC path'  shown above, the SNR is better at DC but not good at intermediate frequencies (30 mHz - 1kHz).

So the idea to keep the good SNR over the frequency range of interest is to combine these 'DC path' and 'AC path' in a clever way.

     In our case, the 'DC path' signal is not as good as the 'AC path' signal above 30 mHz, so we cut off those high frequency signals by using a digital low pass filter.

In addition to it, I put a gain of 1000 in order to match the relative gain difference between 'DC path' and 'AC path'.

Then the resultant signal after the summing point keeps the good SNR with a flat transfer function up to 1 kHz. 

Quote:

Two different measurement have been performed for a test of the green locking last night.

Everything is getting better. yes. yes.

  4354   Thu Feb 24 21:46:30 2011 kiwamuUpdateGreen Lockinginstalled a summing box

In this past weekend I replaced a summing amplifier for the end green PDH locking by a home-made summing circuit box in order to increase the control range.

It's been working well so far.

However due to this circuit box, the demodulation phase of the PDH locking is now somewhat different from the past, so we have to readjust it at some point.

 

(background)

    At the X end station, the voltage going to the NPRO PZT had been limited up +/- 4 V because of the summing amplifier : SR560.

Therefore the laser was following the cavity motion only up to ~ +/- 4 MHz, which is not wide enough. (it's okay for night time)

So we decided to put a passive circuit instead of SR560 to have a wider range.

 

(summing box)

   We made a passive summing circuit and put it into a Pomona box.

The circuit diagram is shown below. Note that we assume the capacitance of the 1W Innolight has the same capacitance as that of the PSL Innolight (see #3640).

summing_box.png

The feedback signal from a PDH box goes into the feedback input of the circuit.

Then the signal will be low passed with the corner frequency of 200 kHz because of the combination of RC (where R is 681 Ohm and C is capacitance of the PZT).

Because of this low pass filter, we don't drive the PZT unnecessarily at high frequency.

On the other hand the modulation signal from a function generator goes into the other input and will be high passed by 50 pF mica capacitor with the corner frequency of 200 kHz.

This high pass filter will cut off noise coming from the function generator at low frequency.

In addition to it, the 50 pF capacitor gives a sufficient amount of attenuation for the modulation because we don't want have too big modulation depth.

 

Here is a plot for the expected transfer functions.

You can see that the modulation transfer function (blue curve) has non-zero phase at 216 kHz, which is our modulation frequency.

transfer_func.png
 

 

  4355   Fri Feb 25 01:48:54 2011 valeraUpdateASCmc auto alignment status

 I made several scripts to handle the mcass configuration and sensing measurements:

- The scripts and data are in the scripts/ASS directory

- The mcassUp script restores the settings for the digital lockins: oscillator gains, phases, and filters. The MC mirrors are modulated in pitch at 10, 11, 12 Hz and in yaw at 10.5, 11.5, and 12.5 Hz. The attached plot shows the comb of modulation frequencies in the MCL spectrum.

- The mcassOn and mcassOff scripts turn on and off the dither lines by ramping up and down the SUS-MC1_ASCPIT etc gains

- The senseMCdecenter script measures the response of the MCL demodulated signals to the decentering of the beam on the optics by imbalancing the coil gains by 10% which corresponds to the shift of the optic rotation point relative to the beam by 2.65 mm (75mm diameter optic) and allows calibration of the demodulated signals in mm of decentering. The order of the steps was MC1,2,3 pitch and MC1,2,3 yaw. The output of the script can be redirected to the file and analyzed in matlab. The attached plot shows the results. The plot was made using the sensemcass.m script in the same directory.

- The senseMCmirror script measures the response of the MCL demodulated signals to the mirror offsets (SUS-MC1_ASCPIT etc filter banks). The result is shown below (the sensemcass.m script makes this plot as well). There is some coupling between pitch and yaw drives so the MC coils can use some balancing - currently all gains are unity.

- The senseMCdofs scripts measures the response to the DOF excitation but I have not got to it yet.

- The next step is to invert the sensing matrix and try to center the beams on the mirrors by feeding back to optics. Note that the MC1/MC3 pitch differential and yaw common dofs are expected to have much smaller response than the other two dofs due to geometry of this tree mirror cavity. We should try to build this into the inversion.

Attachment 1: mcditherlines.pdf
mcditherlines.pdf
Attachment 2: mcdecenter.pdf
mcdecenter.pdf
Attachment 3: mcmirror.pdf
mcmirror.pdf
  4356   Fri Feb 25 10:11:56 2011 steveUpdateSAFETYhow not to

The beam of IR for doubling  is clipping on bnc cable to green beam transmitted pd.

Attachment 1: Presentation1.jpg
Presentation1.jpg
  4358   Fri Feb 25 14:35:06 2011 Larisa ThorneUpdateElectronicsTotal harmonic distortion results for +7dBm mixer

 This experiment deals with measuring the total harmonic distortion (THD) contribution of mixers in a circuit.

(a circuit diagram is attached) where:

Mixer: ZFM-3-S+ at +7dBm

Attenuator: VAT-7+, at +7dB

Low-pass filter: SLP-1.9+, which is set to DC-1.9MHz

 

The total harmonic distortion can be calculated by the equation: 


\mbox{THD} =  \frac{V_2^2 + V_3^2 + V_4^2 + \cdots + V_\infty^2}{V_1^2}

where Vn represents the voltage of the signal at a certain harmonic n.

 

In this experiment, only the voltages of the first three harmonics were measured, with the first harmonic at 400Hz, the second at 800Hz, and the third at 1.2kHz. The corresponding voltages were read off the spectrum analyzer after it had time averaged 16 measurements. (picture of the general shape of the spectrum analyzer output is attached)


(results for this mixer's particular configuration are on the pdf attached)

 

There really isn't that much correlation between the modulations and the resulting THD.

We won't know how good these numbers are until more experiments on other mixers are done, so they can be compared. Since the rest of the mixers are relatively high levels (+17dBm, +23dBm in comparison to this experiment's +7dBm), an RF amplifier will need to be hooked up first to do any further measurements.

 

 

 

 

 

Attachment 1: THDcircuit.jpg
THDcircuit.jpg
Attachment 2: Photo_on_2011-01-17_at_12.25.png
Photo_on_2011-01-17_at_12.25.png
Attachment 3: THDwithoutamp.pdf
THDwithoutamp.pdf
  4360   Sat Feb 26 00:25:38 2011 KojiUpdateIOOMC servo improvement

[Rana / Koji]

The MC servo loop has been investigated as the MC servo was not an ideal state.

With the improved situation by us, the attached setting is used for the MC and the FSS.
The current UGF is 24kHz with phase margin is ~15deg, which is unbearably small.
We need to change the phase compensation in the FSS box some time in the next week.


- We found the PD has plenty of 29.5MHz signal in in-lock state. This was fixed by reducing the LO power and the modulation depth.

- The LO power for the MC demodulator was ~6dBm. As this was too high for the demodulator, we have reduced it down to 2dBm
by changing attenuator to 12dB (at 6 oclock of the dial) on the AM stabilization box.

- The RF power on the MC PD was still too high. The PD mush have been saturated. So the modulation slider for 29.5MHz was moved
from 0.0 to 5.0. This reduced the 29.5MHz component. (But eventually Koji restored the modulation depth after the servo shape has been modified.)

- The openloop gain of the loop has been measured using EXC A/TEST1/TEST2. The UGF was ~5kHz with the phase mergin of ~10deg. 

- This quite low phase margin is caused by the fact that the loop has f^-2 shape at around 4k-100kHz. The reference cavity has
the cavity pole of 40kHz or so while the IMC has the pole of ~4kHz. Basically we need phase lead at  around 10-100kHz.

- We decided to turn off (disable) 40:4000 boost of the MC servo to earn some phase. Then MC did not lock. This is because the LF gain was not enough.
So put Kevin's pomona box in the FAST PZT path (1.6:40). By this operation we obtain ~75deg (max) at 560Hz, ~35deg at 5kHz, ~20deg at 10kHz.

- In this setup the UGF is 24kHz. Still the phase margin is ~15kHz. This phase lag might be cause by 1)  the MC servo circut 2) PMC cavity pole

NEXT STEP

- Put/modify phase lead in the FSS box.
- Measure the PMC cavity pole
- Measure and put notch in the PZT path
- Increase the UGF / measure the openloop TF

Attachment 1: fss_servo.png
fss_servo.png
Attachment 2: mc_servo.png
mc_servo.png
  4361   Sat Feb 26 02:33:16 2011 kiwamuUpdateGreen Lockingsidebands on beatnote

The power ratio of the beatnote signal vs. the 216kHz sideband has been measured.

The measured ratio was -55 dB, which is smaller by about 20 dB than Aidan's estimation.

To confirm this fact we should check the modulation depth of the end PDH somehow.

 

The below is a picture showing the sidebands around the beatnote locked at 66.45 MHz.

Other than the +/-216 kHz sidebands, we can see some funny peaks at +/- 50 kHz and +/-150 kHz

I wonder if they come from the servo oscillation of the MC servo whose UGF is at 24 kHz.  We can check it by unlocking the MC.

beat_note.png

Quote: #4351 by Aidan

So, on the vertex PD, the power of the 80MHz +/-200kHz sidebands should be around sqrt(0.15)*0.05 = 0.02 = 2% of the 80MHz beatnote.

Once we get the green and IR locked to the arm again, we're going to look for the sidebands around the beatnote.

  4362   Sun Feb 27 09:43:59 2011 AidanUpdateGreen Lockingsidebands on beatnote

Can we set up a fiber-PD on the end table to look at the beat between the "end laser IR beam" and the "PSL IR beam fiber-transmitted end beam"? 

We should see the same thing on that PD that we see on the green PD (plus any fiber noise and I'm not really sure how much that'll be off the top of my head). If we unlock the lasers from the arm cavity then the free-running noise of the lasers wrt to each other will probably swamp the 50kHz and 150kHz signals. Maybe we could lock the end laser to the free-running PSL by demodulating the beat note signal from the fiber-PD and then we could look for the extra sidebands in the IN-LOOP signal. Then we could progressively lock the PSL to the MC and arm cavity and see if the sidebands appear on the fiber-PD at some point in that process. 

It's possible that the 216kHz drive of the PZT on the Innolight is somehow driving up some sub-harmonics in the crystal. I think this is unlikely though: if you look at Mott's measurements of the Innolight PZT response, there are no significant PM resonances at 50 or 150kHz.

 

Quote:

Other than the +/-216 kHz sidebands, we can see some funny peaks at +/- 50 kHz and +/-150 kHz.

 

Quote: #4351 by Aidan

So, on the vertex PD, the power of the 80MHz +/-200kHz sidebands should be around sqrt(0.15)*0.05 = 0.02 = 2% of the 80MHz beatnote.

Once we get the green and IR locked to the arm again, we're going to look for the sidebands around the beatnote.

 

ELOG V3.1.3-