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  40m Log, Page 118 of 341  Not logged in ELOG logo
ID Date Author Typeup Category Subject
  3481   Fri Aug 27 19:30:31 2010 ranaUpdateCDSSLOW controls

For the future SLOW controls our current plan is to keep using the VME based stuff and associated processors (Baja, Motorola, etc.). This is not

a sustainable plan since these are obsolete and eventually will die. One option is to use these boxes from Diamond Systems:



  3482   Fri Aug 27 22:09:37 2010 JenneUpdatePSLThe beginnings of the new PSL

[Rana, Jenne]

Like a new phoenix, the 40m PSL is in the process of being reborn...


We cleared many old optics and components (including Alberto's favorite periscope) off of the north end of the PSL table.  Some optics are stored on the SP table, others on the shelf inside the PSL enclosure.

The new Innolight 2W NPRO is on the table, the PMC has been moved, and the main path of the laser has been sketched out using steering mirrors. Since we still don't have a beam, we're roughly placing all of our optics, and we'll finalize the alignment after turning on the laser.

Using a leveled HeNe, I checked the height of optics we should use to match the height of optics in the chambers by shining the light at the first steering mirror in the chamber, and ensuring that the beam hit the center of that optic .  Since the new PSL table height is identical to the AP table, it's not a surprise that from now on we will be using a 4" beam height on the PSL table, rather than the old PSL 3" beam height.

On the to-do list is to make a plate with 4 through holes to raise the PMC up by 1 inch, and to make an adapter plate (or come up with another plan) for mounting the AOM that goes directly after the NPRO/Faraday, among many other things.  We also still need to make some space for the RefCav to be put in its new place on the table, and then install it with Steve's help.   

  3483   Sat Aug 28 01:02:31 2010 ranaUpdatePSLThe beginnings of the new PSL

In fact, many of the mounts need to be adapted to 4": the beefy steering mirrors going into the PMC, the PMC RFPD, the ISS AOM, the Faraday between the NPRO and the AOM, the NPRO itself, the ISS PDs.

Also for the FSS: the 21.5 MHz EOM, the PBS, the AOM, the refcav periscope, and the RFPD.

Its obvious, in retrospect, that we would have to do this, but it somehow didn't occur to me until actually trying to put things on the table...

The NPRO itself is already tapped with 3 (metric) M3 holes. It also has 4 (un-tapped) holes at its 4 corners which look like they are for feet. Anyone have a mount design for the Innolight NPRO already?

We also started labeling the table with the new coordinate system. In this system, the NE corner is the origin. The screw hole which is most NE is 1,1. The numbering increases in the south (+X) direction and goes negative in the west (-Y) direction.

  3484   Sat Aug 28 08:17:51 2010 AbertoUpdateElectronicsFSS Frequency Generation Box under test

I've taken the FSS frequency generation box out of the 1Y1 rack. It's sitting on one of the electronics benches. I'm measuring its phase noise.

  3485   Sun Aug 29 21:18:00 2010 ranaUpdateComputerskallo -> rossa

We changed the name of the new control room computer from kallo to rossa (since its red).

I also tried to install the nVidia graphics driver, but failed. I downloaded the one for the GeForce 310

for x86_64 from the nVidia website, but it failed to work. I installed it, but then X windows wouldn't start.

I've left it running a basic VESA driver.

Kiwamu updated the host tables to reflect the name change. We found that both rossa and allegra were

set up to look at the old 131.* DNS computers and so they were not resolving correctly. We set them up for new way.

  3486   Mon Aug 30 11:41:34 2010 kiwamuUpdateComputersdisable sendmail and isdn

 {Rana and Kiwamu}

Yesterday we disabled the sendmail daemon and the isdn daemon on allegra because we don't need these daemons always running.


-   How to disable/enable daemons:

sudo ntsysv

  3489   Mon Aug 30 18:35:22 2010 JenneUpdateWienerFilteringSecret Hiding Place for Raw Data

As it turns out, data seems to fall off the 16Tb drives after ~20 days.  Which makes it a good thing that I saved all of my raw data from my good Mode Cleaner / seismic weekend for offline Wiener Filtering in the following secret place:


It's not linked to the svn, since it's a boatload of data.

  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... 

  3492   Tue Aug 31 02:50:45 2010 kiwamuUpdateCDSvertex suspensions controlled by the new CDS

I plugged the new CDS to the vertex suspensions. 

Now PRM, SRM, ITMs, MCs and BS are under the control of the new CDS. 

From now on we will never go back to the old system.


Though,  the watchdogs are still running on the old system.

So if you need to turn on/off the watchdogs, you can simply enable/disable them from the usual medm screens.

  3493   Tue Aug 31 10:44:17 2010 steveUpdatePEMconcrete sealed

The PSL -leg concrete was sealed with a single coat of SCOFIELD Cureseal-S to minimize shedding of particles.

The optical table was covered  and optics were removed from the shelf. Accelerometers were turned off.

  3494   Tue Aug 31 11:50:14 2010 kiwamuUpdateCDSmaximum number of BIOs

 { Joe and Kiwamu },

 Now we  are able to compile the model file with more than 4 binary input/outputs (BIOs).

 As I wrote in a past entry (see here), the number of the BIOs was limited to 4, which is not enough for us.


  We modified a header file called "cdsHardware.h"  in order to allow model files having more than four BIOs.

The header file lives under /cvs/cds/caltech/advLigoRTS/src/include/drv/.

There was a sentence defining the maximum number in the file:

 #define MAX_DIO_MODULES         4.

We changed this to

 #define MAX_DIO_MODULES         8.

  3495   Tue Aug 31 13:31:00 2010 steveUpdatePEMroom temp lowered

I lowered room 101 thermostat setting from 74F to 72F

  3497   Tue Aug 31 15:26:46 2010 ranaUpdatePEMroom temp lowered

And I raised it back to 73F. The thermometers on the wall show 74-75F as the actual room temp. The dial on the temperature controller is not calibrated.

  3498   Tue Aug 31 16:42:26 2010 josephbUpdateCDSTemporarily reverting to CDS revision 2005

Apparently updating to the latest revision of the RCG has some issues with diaggui and awgtpman.  Alex had to do some recompiling up at Hanford which apparently took him some time.  He'll be coming by tomorrow to try to bring those codes to the front end machines.

As a temporary fix, until Alex gets here tomorrow, we're reverting to the 2005 revision in the svn of the cds code.  I'm placing it in the location it is supposed to go in the new advLIGO scheme, which is /opt/rtcds/caltech/c1/core/, which is where Keith had it at LLO.  Once we get the new codes working, we will do an svn update on that location and migrate our work to that install location, at which point I'll remove the old /cvs/cds/caltech/cds/advLigoRTS/ location.

  3499   Tue Aug 31 17:58:38 2010 AlbertoUpdateElectronicsFSS Frequency Generation Box - Phase Noise

A few weeks ago, on Jul 24, Rana and I measured the phase noise of the FSS frequency box (aka the 'Kalmus Box'). See elog entry 3286.

That time, for some reason, we measured a phase noise higher than we expected; higher than that of the Marconi.

I repeated the measurement today using the SR785 spectrum analyzer. Here is the result:


(The measurement of July 24 on the plot was not corrected for the loop gain. The UGF was at about 30 Hz)

To make sure that my measurement procedure was correct, I also measured the combined phase noise of two Marconis. I then confirmed the consistency of that with what already measured by other people in the past (i.e. Rana elog entry 823 in the ATF elog).

This time the noise seemed reasonable; closer to the Marconi's phase noise, as we would expect. I don't know why it was so bad on July 24.

The shoulder in the Marconi-to-Marconi measurement between 80Hz and 800Hz is probably due to the phase noise of the other Marconi, the one used as LO.

I'm going to repeat the measurement connecting the setup to the DAQ, and locking the Marconi to the Rubidium standard.

Ultimately, the goal is to measure the phase noise of the new Sideband Frequency Generation Box of the 40m Upgrade.

  3500   Tue Aug 31 19:46:00 2010 ranaUpdatePSLPSL upgrade update
  1. Steve is handling the mount height increase for the PMC and RC steering mirrors, as well as a mount (non-steerable) for the ISS' AOM.
  2. Rana is working on the laser mount.
  3. Jenne is drawing and getting the PMC mount made.
  4. We got the lenses from CVI for the mode matching, but not the metric screws for the laser mounting. I am tempted to tap holes in the laser base.
  3502   Wed Sep 1 08:28:43 2010 KojiUpdatePSLPSL upgrade update

  1. We got the lenses from CVI for the mode matching, but not the metric screws for the laser mounting. I am tempted to tap holes in the laser base.

I am feeling that it is ok to carefully make new holes and threads as far as the holes do not penetrate the plate.
The thickness of the plate can be measured by the four holes at the corners.


  3505   Wed Sep 1 10:54:15 2010 steveUpdatePEM more crane balancing

Crane balancing at the south end is continuing today.

  3506   Wed Sep 1 11:34:39 2010 AlbertoUpdateElectronicsFSS Box Phase Noise from DAQ

I measured the phase noise of the LO output of the FSS box from the DAQ. I'm attaching the results.

As we expected, the measurement is limited by the internal phase noise of the Marconi.


The measurement was done as shown in this diagram.


  3507   Wed Sep 1 12:24:47 2010 josephbUpdateCDSTrying to get up to date CDS code runnning

Alex, Joe:

We copied the latest x02 to c1x02 and modified to our the config block in it.

We removed gds_node_id.  We just have one number now, the dcuid, which is unique for each controller, simulated plant and IOP.  Set site to C1 and host to c1sus.

Alex made the latest awgtpman backwards compatible, and checked that into svn.

We installed the latest framecpp onto c1sus from www.ldas-sc.ligo.caltech.edu/packages/ using wget.

wget www.ldas-sc.ligo.caltech.edu/packages/framecpp-1.18 and then used make.

This let us compile diagd on c1sus, using the command make stand in the /advLigoRTS/build area.

We copied gds from the seiteststand over at handford and are trying to build that on megatron.  However, there's a bunch of packages we need for it to install properly.  Alex said he'd work on that later, possibly trying to make some portable binaries.

Checked out the latest dataviewer into /opt/rtcds/caltech/c1/core/daq, however its not quite working yet either.  This is another thing Alex said he'll work on later.

We are also going to test Alex and Rolf's kernel patch over on c1iscex on Centos base kernel (apparently they've been using Gentoo up at hanford for the test stands...) and see how that works.

  3508   Wed Sep 1 12:34:14 2010 ranaUpdateElectronicsFSS Box Phase Noise from DAQ

The differences between this setup and the one used previously is the lack of the 50 Ohm terminator in the mixer output and

that the SR560 readout with the G=100 should come before the first SR560 via T, so as not to be spoiled by the high noise of the G=1 SR560.

  3509   Wed Sep 1 16:29:28 2010 AlbertoUpdateElectronicsFSS Box Phase Noise from DAQ - Measurement setup modified


The differences between this setup and the one used previously is the lack of the 50 Ohm terminator in the mixer output and

that the SR560 readout with the G=100 should come before the first SR560 via T, so as not to be spoiled by the high noise of the G=1 SR560.

I removed the 50 Ohm in-line terminator when I did the measurement with the SR785. The for some reason I was getting more noise, so I removed it.

Now I put it back in and I did the measurement with the DAQ. I also moved the SR560 that amplifies the signal for the DAQ, Tee'ing it with the input of the in-loop SR560.

Now the setup looks like this:


And the phase noise that I measure is this:


Comparing it with the phase noise measured with the previous setup (see entry 3506), you can see that the noise effectively is reduced by about a factor of 2 above 10 Hz.


  3510   Wed Sep 1 17:17:42 2010 ranaUpdateElectronicsFSS Box Phase Noise from DAQ - Measurement setup modified

With the setup now working, we should now test the power filtering for the crystal and amplifier.

  3511   Thu Sep 2 01:44:13 2010 JenneUpdatePSLPSL beam hitting the PMC!

[Rana, Jenne]

More PSL progress. 

The new laser was raised to a 4 inch beam height using basically the most randomly thrown together method possible.  (It'll work just fine for aligning things, but we seriously need to get a nice block made.)  The PMC and the nice Osamu-mirror mount to go into the PMC also have temporary risers, so we'll need to replace them with the real deal as soon as we get things back from the shop.

So far we've got (1) the lens after the laser, (2) a Half Wave Plate (no quarter wave plate yet), (3) steering mirror that will go after the EOM, (4) 2 steering mirrors to get into the PMC, in addition to all of the stuff that we did the other day.  With all of this stuff we've got the beam hitting the 1st PMC mirror. We still don't have the EOM and AOM in the beam path however.

To get the rough alignment that we did, we turned on the new 2W NPRO, operating at the minimum power we could see on a card.  We turned it off after use, so it is still off.  Steve, we left the cable for the interlock sitting on the PSL table on the NW corner....can you please hook it up tomorrow?  Also, after the interlock is installed we should go back to regular running laser hazard mode. 



  3515   Thu Sep 2 16:45:48 2010 josephbUpdateCDSNumbering scheme of the PCI bus

Rolf has recently written a document describing how one should fill out an IO chassis and how the numbering works out.  This can be found in the DCC at Rolf's PCIe numbering guide (T1000523).

Basically it works out that slot 1 corresponds to PCIe number 1, but slot 2 corresponds to PCIe number 6.  And so forth.  The following table gives a quick summary.

Slot 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
PCIe Number 1 6 5 4 9 8 7 3 2 14 13 12 17 16 15 11 10


  3516   Thu Sep 2 17:43:30 2010 josephbUpdateCDSOne working BO output module, others not so much

 Joe and Kiwamu:

We found one bug in the RCG code, where the second input for the CDO32 part (32 binary output) was simply a repeat of the first input, and totally ignored the second input.  This was fixed in the /advLigoRTS/src/epics/util/lib/CDO32.pm file by changing 

$calcExp .= $::fromExp[0];


$calcExp .= $::fromExp[1];

This fix has been added to the svn.  Unfortunately, while we have a single working binary output module, the 2nd and later modules do not seem to be responding at all.  We've done the usual swaping parts of the path in both software and hardware and can't find any bad pieces in our model files or the actual hardware.   That leaves me wondering about the c code, specifically if the CDO32Output[1], CDO32Output[2], and so forth array entries in the code are being handled properly.  I'll try to get some thoughts on it from Alex tomorrow.

  3519   Fri Sep 3 06:55:42 2010 ranaUpdatePSLPSL beam hitting the PMC!


Koji and I inspected and photographed the laser after opening up its case. I then drilled the clearance holes in the 4 corners and tapped holes for 1/4-20. I was careful to tap with the laser sideways, to avoid shavings getting into the laser and suctioned out as much of the pieces as I could. The laser is now mounted on some bad 1/4-20 based NewFocus style pedestals. The riser block can now be made with 1/4-20 through holes and the laser will sit on its for corner feet. We'll make the base aluminum to avoid differential CTE based stress in the laser base.

We checked the level of the laser. With the new mounting the beam is level to within ~1 mrad and has a 4" beam height.



I've mounted the Faraday Rotator from the old MOPA. It has 8-32 mounting holes (who's shafts are curiously not parallel). We need an aluminum block of the proper height (2 3/4" ??) to make a permanent solution.

I've also mounted the thin-film polarizer. This works well, but it also needs a block machined to get the mounting to be less Mickey Mouse.


Pockel Cell for phase correction and 35.5 MHz PMC modulation

The EOM is mounted as before on the angle bracket to align it for P-pol light. The beam now goes cleanly through there. No further mounting hardware required.



The 2 lenses in the 'mode matching telescope' between the laser and the PMC are in place, but not placed with any accuracy.


By sheer luck, I saw the PMC flashing in the TEM27 mode without any alignment from me. Next step is to get the lens positions tuned and then do the beam scan on the beam going towards the PMC to verify the approximate mode matching. This is all crude, but I just want to get the beam going into the vacuum as fast as possible.

  3523   Fri Sep 3 23:42:34 2010 JenneUpdatePSLPSL update of the day

Rana and I were poking around on the PSL table today, getting a few more items raised to the correct height.

I checked the polarization state of the new NPRO by using a HWP to minimize the transmission through a PBS cube, and then compared the power transmitted through the cube vs. reflected.  When the NPRO current was 0.772 \pm 0.001 (as read on the LCD), the transmission through the cube was 1.44mW, while the reflected was 10.53mW.  The reading of the Ophir power meter with no incident light was 0.03mW.  This factor of 10 means that the NPRO beam is ~10% circularly polarized and ~90% linearly polarized.  In order to improve the beam, we need a Quarter Wave Plate, which it turns out we don't have.  We need a QWP!

After that, using the linearly polarized part of my beam (maximizing the transmission through the PBS by rotating my HWP by 45deg), I tried to tune the angle of the polarizers that Rana pulled out of the MOPA.  I think I'm confused / too tired, because I can only get the polarizer to reflect a bunch of light, and I can't get it to pass any significant amount of light through, no matter where in its actuation range I put it (It's on a rotation stage with a few degrees of range).  It should just be a Brewster's Angle thing, and since I already have P-pol coming through the BS cube, this shouldn't be so hard.....

In any case, it may not be useful to do the final fine tuning of these polarizers until they are in their final places.  The hacky stack of mounts that I have has some slop in the position / alignment of the base of the polarizer, so no matter what we'll have to redo the tuning after the mounts are finalized.

  3525   Mon Sep 6 01:46:58 2010 ranaUpdatePSLPSL update of the day

To bypass the polarizer issue, I just used cubes. One I took from the FSS-Refcav path and the other from the power control part of the old MOPA, just downstream of the MOPA's periscope.

We'll swab these out with the thin-film polarizers after we get the mounts made.

With the cubes in, I also installed the Faraday + its 1/2-wave plate. The transmission looks good and we're getting into the PMC and its flashing a TEM00 mode sometimes. I set up a signal generator to drive the SLOW actuator by 1 FSR at 0.1 Hz.

I have set up a PMC transmission camera and transPD so that its easy to align. The flashing mode already allows us to align most of the rest of the table (except FSS).

Our next step should be to run the cables for locking the PMC:

  1. RF cables to the PMC_REFL
  2. Dsub for the PMC RFPD
  3. HV cable between the PMC servo board and the PMC PZT (why is this not RED? we have to make sure to abide by the cabling color code).
  4. RF cable from 35.5 MHz Frequency Reference card to the PMC EOM via the RF summing box on the table.

On Tuesday, we need to make sure that all of our mounts' drawings are in the cue for the shop. I'll put the list of mounts onto the PSL upgrade wiki page.

We also have to come up with a plan for wiring some of the 2W NPRO's channels into the cross-connect so that we can have some laser channels recorded by EPICS.

  3527   Mon Sep 6 20:38:58 2010 KojiUpdateCDSSusension model reviewed

I have reviewed the suspension model of C1SUS and refined it.

It is comaptible to the current one but has minor additions.

  3528   Mon Sep 6 21:08:44 2010 ranaUpdateCDSSusension model reviewed

We must remember that we are using the Rev.B SOS Coil Drivers and not the Rev. A. 

The main change from A->B was the addition of the extra path for the bias inputs. These inputs were previously handled by the slow EPICS system and not a part of the front end. So we used to have a separate bias screen for these than the bias which is in the front end. The slow bias is what was used for the alignment to avoid overloading the range of the main coil driver path.

  3529   Mon Sep 6 22:09:11 2010 AlbertoUpdateElectronicsRF Frequency Generation Box heat sink installed and tested

Last week I noticed that the high power amplifiers in the Frequency Generation Box became hot after 2 hours of continuous operation with the lid of the box closed. When I measured their temperature it was 57C, and it was still slowly increasing (~< 1K/hr).
According to the data sheet, their maximum recommended temperature is 65C. Above that their performances are not guaranteed anymore.

These amplifiers aren't properly dissipating the heat they produce since they sit on a plastic surface (Teflon), and also because their wing heat dissipator can't do much when the box is closed. I had to come up with some way to take out their heat.
The solution that I used for the voltage regulators (installing them on the back panel, guaranteeing thermal conduction but electrical isolation at the same time) wouldn't be applicable to the amplifiers.

I discussed the problem with Steve and Koji and we thought of building a heat sink that would put the amplifier in direct contact with the metal walls of the box.
After that, on Friday I've got Mike of the machine shop next door to make me this kind of L-shaped copper heat sink:


On Saturday, I completely removed the wing heat dissipator, and I only installed the copper heat sink on top of the amplifier. I used thermal paste at the interface.

I turned on the power, left the lid open and monitored the temperature again. After 2 hours the temperature of the amplifier had stabilized at 47C.

Today I added the wing dissipator too, and monitored again the temperature with the lid open. then, after a few hours, I closed the the box.
I tracked the temperature of the amplifier using the temperature sensors that I installed in the box and which I have attached to the heat sink.
I connected the box temperature output to C1:IOO-MC_DRUM1. With the calibration of the channel (32250 Counts/Volt), and Caryn's calibration of the temperature sensor (~110F/Volt - see LIGO DOC # T0900287-00-R), the trend that I measured was this:


The heat sink is avoiding the amplifier to overheat. The temperature is now compatible with that of the other component in the box (i.e., crystal oscilaltors, frequency multiplier).
Even with the lid closed the temperature is not too high.

Two things remain untested yet:
1) effect of adding a MICA interface sheet between the heat sink and the wall of the chassis. (necessary for gorund isolation)
2) effect of having all 3 amplifiers on at the same time

I am considering opening air circulation "gills" on the side and bottom of the chassis.

Also we might leave the box open and who ever wants can re- engineer the heat sink.

For posterity.
- Ideally we would like that the heat sink had the largest section area. A brick of metal on top the amplifier would be more effective. Although it would have added several pounds to the weight of the box.
- We need these amplifiers in order to have the capability to change the modulation depth up to 0.2, at least. The Mini-Circuit ZHL-2X-S are the only one available off-the-shelf, with a sufficiently low noise figure, and sufficiently high output power.

  3530   Tue Sep 7 08:56:00 2010 AlbertoUpdateElectronicsFrequency Generation Box Assembly - Phase Noise Measurements

Here are the results of my phase noise measurements on the 7 outputs of the Frequency Generation Box. (BIN=95L applied by DTT). See attached pdf for a higher definition picture.


The plot shows that the phase noise of the 11 MHz outputs (Source, EOM modulation signal, Demodulation signal) is as low as that of the Marconi. The Marconi is limiting my measurement's resolution.

The mode cleaner signal's oscillator (29.5 MHz output, blue trace) is higher than the 11MHz above 1KHz.

The 55MHz signals have all the same phase noise (traces overlapped), and that is higher than the 11 MHz ones from about 100Hz up. i don't know what's going on.

I need to use the spare 11MHz Wenzel crsytal to have a better reference source for the measurement.

  3532   Tue Sep 7 13:31:49 2010 AlbertoUpdateElectronicsRF System - Frequency Distribution Box - Priority Plan

We need a distribution unit in the LSC rack to: 1) collect the demod signals coming from the Frequency Generation Box 2) adjust the power level 3) generate 2nd harmonics (for POP) 4) distribute the demod signals to the single demodulation boards.

The base line plan is the following:


The box can be build up gradually, but the priority goes to these parts:


I need help for this work. I know exactly how to do it, I just don't have the time to do it all by myself.

 Besides the Distribution Box, the demodulation part of the upgrade would still require two steps:

1) upgrade the Band Pass Filters of the demodulation boards (I have all the parts)

2) cabling from the distribution box to the demod board (one-afternoon kind of job)

  3534   Tue Sep 7 15:31:28 2010 josephb, alexUpdateCDSBinary Output working/ IO chassis fixed

As noted previously, we were having problems with getting multiple 32 channel binary output cards working.  Alex came by and we eventually tracked the problem down to an incorrect counter in the c code.  This has been fixed and checked into the CDS svn repository.  I tested the actual hardware and we are in fact able to turn our test LEDs on with multiple binary output boards.


Alex and I also looked at the non-functional IO chassis (the one which wouldn't sync with the 1PPS signal and wasn't turning on when the computer turned on.  We discovered one corner of the trenton board wasn't screwed down and was in fact slightly warped.  I screwed it down properly, straightening the board out in the process.  After this, the IO chassis worked with a host interface board to the computer and started properly.  We were able to see the boards attached as well with lspci.  So that chassis looks to be in working condition now.

Onwards to the RFM test.

  3542   Wed Sep 8 00:01:07 2010 rana, valeraUpdatePSLPMC update

We ran the cables for the PMC: The RF cable for the 35.5 MHz drive was cheap and so we swapped the 29.5 MHz cable for it.

There now remain 1 RG-174 cable to drive the FSS PC (21.5 MHz) and 3 Heliax for the Kiwamu Tri-Mod EOM (11, 29.5, and 55 MHz).

We also changed the BLACK HV drive cable for the RED one (previously used for the MZ). All HV cables MUST be RED.

The BLACK cable is now used for the PMC_REFL DC.

The Heliax cables are routed onto the table - it remains a Alberto/Kiwamu job to strain relieve them and attach them to the TriMod box and EOM in the morning.

The PMC is locked and we did some partially bootless alignment and mode-matching. It locks easily on a TEM00 mode (with very poor visibility), but the

rest of the beam train can now be aligned while Valera does the PMC matching mambo.   


  3543   Wed Sep 8 09:50:13 2010 ranaUpdatePSLPSL update

Also, Kiwamu has modified the layout drawing to add the green PLL stuff. This has collapsed the reference cavity's wave function placing it close to its original position.

WE (maybe Valera and Steve) can now put the reference cavity back on the table.

  3544   Wed Sep 8 11:46:53 2010 kiwamuUpdatePSLupdate of the layout

I put some green stuff on the layout drawing.

I continue to refine the positions of these stuff.


Notes :

 1. I flipped the reference cavity. So now the cavity is sitting on the left hand side of the layout.

  2. I removed the ISS stuf. We should think about where ISS should be.


Also, Kiwamu has modified the layout drawing to add the green PLL stuff. This has collapsed the reference cavity's wave function placing it close to its original position.

WE (maybe Valera and Steve) can now put the reference cavity back on the table.


  3546   Wed Sep 8 14:44:37 2010 josephbUpdateCDSUpdated parse_mdl_to_ipc.py and feCodeGen.pl

I updated parse_mdl_to_ipc.py to correctly work with the 3 new cdsIPCx parts, namely cdsIPCx_PCIE (for dolphin connections), cdsIPCx_RFM (for our traditional reflected memory connections), and cdsIPCx_SHMEM (local shared memory on the computer).  These parts replaced cdsIPCx awhile back (see here ).

The code now correctly counts each type independantly with regards to ipcNum (I.e. you can have ipcNum = 0 for RFM and ipcNum = 0 for SHMEM for example).


I also went in and modified a few sections of the feCodeGen.pl (in /opt/rtcds/caltech/c1/core/advLigoRTS/src/epics/util/) so as to properly assign names to matrix adl files, matrix of filter bank adl files, and filter bank adl files.

  3547   Wed Sep 8 16:17:58 2010 steveUpdatePEMparticle counter problem

I played with the particle counter this morning. Now it's running and reading the correct numbers on the old COCHECKLIST.adl medm screen.

However, it can not be seen with dataviewer.

Koji just rebooted the frame builder and the problem was solved.

  3548   Thu Sep 9 05:58:04 2010 kiwamuUpdatePSLmode matching from PMC to IMC

 I started mode matching of the beam going to IMC. The work is still going on.

According to Rana's calculation (see here), I put the first lens (f=200mm) in between two steering mirrors after PMC.

The distance from PMC to the first lens was adjusted by using a metal ruler.  So I believe the accuracy is something like 1mm.

I aligned the beam path going through the broadband EOM and the mode matching lenses.


  I could find the optimum position for the second lens  (f=-150mm) by sliding the position of the lens and measuring the mode after it.

But the optimum position looked a bit far from the EOM. It's off by about 3-4 inch from the designed position.

Somehow I feel that the beam before the second lens goes with a smaller divergence angle than that of designed.

So tomorrow I am going to restart the work from checking the mode before the second lens.

Maybe at first I should measure the mode without going through the EOM because it changes the waist position and makes the system not straightforward.

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

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

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

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


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

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


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

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

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


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

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

Atm2,   24V line to interlock rerouted

Atm3,   job is completed




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

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

Please  come forward voluntarily.

  3551   Thu Sep 9 11:31:54 2010 steveUpdatePEMaccelerometer cable connection

I turned off/on the power to the accelerometers in order to re rout their connections. I found cable connector body-nut  #3 loose to Accelerometer 2X This connector should be checked for solid performance.

  3552   Thu Sep 9 12:02:03 2010 AlbertoUpdateElectronicsFrequency Generation Box - Amplitude Noise Measurements

I measured the amplitude noise of the source outputs and the EOM outputs of the Frequency Generation box.

the setup I used is shown in this diagram:


(NB It's important that the cables from the splitter to the RF and LO inputs of the mixers are the same length).

The results of the measurements are shown in the following plot:



1) both Crystals (29.5MHz and 11MHz) have the same noise

2) the 55MHz source's noise is bigger than the 11 MHz (~2x): the frequency multiplication and amplification that happen before it, add extra noise

3) the noise at EOM outputs is ~2x bigger than that of the relative sources


When I have the chance, I'll plot the results of my calculations of expected noise and compare them with the measurements.

  3553   Thu Sep 9 14:42:40 2010 josephbUpdateCDSUpdating suspensions model

I've been working on updating the suspensions model, incorporating Koji's refinements as well as trying to simplify the model and making it less cluttered. 

This had the side benefit of making an incorrect connection obvious.  I had incorrectly wired the ASCPIT input to be summed into the yaw path, and the ASCYAW input into the pitch path.  This has been corrected.

I've finished a single optic, and now I am in the process of propagating the changes to all the optics, as well as cleaning up the overall diagram using Rolf's new tags, which make things much less cluttered.  I've attached a screenshot of the PRM optic control model, and will be updating the Matlab web export once I've updated the full model.

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

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

  3558   Sat Sep 11 22:42:07 2010 valeraUpdatePSLPSL update

- The PMC REFL PD was moved from the temporary location to the one called for by the PSL layout (picture attached). The leakage beams were dumped.

- The FSS reference cavity was aligned using temporary periscope and scanned using NPRO temperature sweep. The amplitude of the sweep (sine wave 0.03 Hz) was set such that the PMC control voltage was going about 100 V p-p with. With rough alignment the visibility was as high as 50% - it will be better when the cavity is locked and better aligned but not better than 80% expected from the mode astigmatism that Tara and I measured on Thursday. The astigmatism appear to come from the FSS AOM as it depends on the AOM drive. We reduced the drive control voltage from 5 V to 4V beyond that the diffraction efficiency went below 50%. The FSS REFL PD was set up for this measurement as shown in the attached picture. There is also a camera in transmission not shown in the picture.

  3560   Sun Sep 12 23:02:53 2010 valeraUpdate PMC mode matching

Kiwamu and I found that the first lens in the PMC mode matching telescope was mislabeled. It is supposed to be PLCX-25.4-77.3-C and was labeled as such but in fact it was PLCX-25.4-103.0-C. This is why the PMC mode matching was bad. We swapped the lens for the correct one and got the PMC visibility of 82%. The attached plot shows the beam scans before and after the PMC. The data were taken with the wrong lens. The ABCD model shown in the plot uses the lens that was there at the time - PLCX-25.4-103.0-C. The model for the PMC is just the waist of 0.371 mm at the nominal location. The snap shot of the ABCD file is attached. The calculation includes the KTP for FI and LiNb for EOM with 4 cm length. The distances are as measured on the table.

  3561   Sun Sep 12 23:16:52 2010 valeraUpdate FSS mode matching

The attached plot shows the beam scans of the beam leaking from the back mirror of the PMC to the BS cube that first turns the S-pol beam 90 deg to the AOM and then transmits the AOM double passed and polarization rotated P-pol beam to the reference cavity. The beam from the PMC is mode matched to the AOM using a single lens f=229 mm. The ABCD file is attached. The data were taken with VCO control voltage at 5 V. We then reduced the voltage to 4 V to reduce the astigmatism. Tara has the data for the beam scan in this configuration in his notebook.

The beam from AOM is mode matched to the reference cavity using a single lens f=286.5 mm. The ABCD file is attached.

ELOG V3.1.3-