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ID Date Author Typeup Category Subject
  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];

to

$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!

NPRO

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.

 

Faraday

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.

 

Lenses

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.

Attachment 1: suspension_model.pdf
suspension_model.pdf
  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:

DSC_2467.JPG

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.

DSC_2433.JPG
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:

2010-09-06_FreqBoxAmplifierTemperatureTrend.png

Conclusion
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.

2010-09-03_FreqBoxPhaseNoise_AllOutputsComparison_smooth.png

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.

Attachment 2: 2010-09-03_FreqBoxPhaseNoise_AllOutputsComparison_smooth.pdf
2010-09-03_FreqBoxPhaseNoise_AllOutputsComparison_smooth.pdf
  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:

Visio-RFsystem_plan_distributiont.png

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

 RFsystem_plant_distribution_priority.png

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.

Quote:

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.

 

Attachment 1: 40mPSL.png
40mPSL.png
  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

Quote:

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

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

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

 

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

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

Atm2,   24V line to interlock rerouted

Atm3,   job is completed

 

SAFETY GLASSES REQUIRED !  SAFETY GLASSES REQUIRED!

 

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

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

Please  come forward voluntarily.

Attachment 1: P1060813.JPG
P1060813.JPG
Attachment 2: P1060814.JPG
P1060814.JPG
Attachment 3: P1060816.JPG
P1060816.JPG
  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:

FreqBoxAmplitudeNoiseMeasurementSetup.png

(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:

 FreqBoxAmplitudeNoise_BusbyBox_AllChannels.png

Considerations:

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.

Attachment 1: SingleSUS.png
SingleSUS.png
  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.

Attachment 1: DSC_2502.JPG
DSC_2502.JPG
Attachment 2: DSC_2505.JPG
DSC_2505.JPG
  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.

Attachment 1: pmc.pdf
pmc.pdf
Attachment 2: pmc-abcd.tiff
  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.

Attachment 1: fss.pdf
fss.pdf
Attachment 2: fssaom-abcd.tiff
Attachment 3: fssrc-abcd.tiff
  3562   Mon Sep 13 00:19:32 2010 ranaUpdate VCO Driver Output power v. slider control voltage

I measured the RF power output of the VCO Driver box as a function of slider value. I measured using the Gigatronics Handheld power meter and connected to the AOM side of the cable after the white Pasternak DC block.

* at low power levels, I believe the waveform is too crappy to get an accurate reading - that's probably why it looks non-monotonic.

* the meter has a sticker label on it saying 'max +20 dBm'. I went above +20 dBm, but I wonder if maybe the thing isn't linear up there...

Attachment 1: vco.png
vco.png
  3564   Mon Sep 13 10:22:48 2010 josephbUpdateCDSRCG bugs/feature request wiki page

I've started a wiki page under the Upgrade 09/New CDS section regarding known bugs and pending feature requests for the Real Time Code Generator.   It can be found at http://lhocds.ligo-wa.caltech.edu:8000/40m/Bugs_and_Pending_Feature_requests_for_the_RCG.  If you have any ideas to improve the RCG or encounter a bug in the code generation process (say a particular part doesn't work inside subsystems for example), please note them here.

Currently there are bugs with excitation points (they don't work inside of a subsystem block) and tags (they don't respect scope and only 1 "from" tag for each "goto" tag connected to the output of a subsystem block).

  3565   Mon Sep 13 11:40:50 2010 AlbertoUpdateElectronicsFrequency Box Documentation Added to the SVN

I uploaded all the material about the RF frequency Generation Box into the SVN under the path:

https://nodus.ligo.caltech.edu:30889/svn/trunk/docs/upgrade08/RFsystem/frequencyGenerationBox/

I structured the directory as shown in this tree:

freqBoxSVNdierctoryStructure.png

I'm quickly describing in a section of the Rf system upgrade document with LIGO # T1000461.

  3566   Mon Sep 13 11:49:34 2010 kiwamuUpdatePSLmode matching from PMC to IMC

I have been working on the mode matching lenses which are sitting after the boradband EOM.

Last Friday I checked the mode profile after the first mode matching lens (f=-150mm). The measured mode was good.

According to the calculation done by ABCD software, the waist size is supposed to be 80.9 um after that lens.

The measured waists are 80.5 um for the vertical mode and 79.4 um for the horizontal mode.

The screenshot of the ABCD's result and the plot for the mode measurement are shown below.

I didn't  carefully check the mode after the last convex lens (f=200mm), but it must be already good because the beam looks having a long rayleigh range.

Now the beam is reflected back from MC1 and goes to the AP table since I coarsely aligned the beam axis to the MC.

newMM.png  psl_mmt1.png

 

/****  fitting result ****/

w0_v =  80.4615      +/- 0.1695 [um] 

w0_h =  79.4468      +/- 0.1889 [um]

z_v =  -0.115234        +/- 0.0005206  [m]

z_h =  -0.109722        +/- 0.0005753 [m]

 

  3568   Mon Sep 13 19:41:38 2010 ranaUpdatePSLFSS AOM alignment

The IR sensitive Olympus 570 camera gives us a really nice view of these IR beams. Its actually a lot better than what you can get with the analog IR viewers:

 

PSLAOMdogs
  3569   Mon Sep 13 21:52:53 2010 kiwamuUpdateGreen Lockingthe X end laser is ON

 I turned ON the laser at the X end station, which had been OFF for several weeks because of the crane business.

Now the green beam hits the ITMX and I got a reflection back to the end table.   

This green beam will be a nice reference when we install the green periscope in the chamber.

If it's necessary, feel free to correct the alignment of the green beam during my absence.

  3572   Tue Sep 14 18:07:41 2010 AlbertoUpdateElectronicsFrequency Box Documentation Added to the SVN

I completed a LIGO document describing design, construction and characterization of the RF System for the 40m upgrade.

It is available on the SVN under https://nodus.ligo.caltech.edu:30889/svn/trunk/docs/upgrade08/RFsystem/RFsystemDocument/

It can also be found on the 40m wiki (http://lhocds.ligo-wa.caltech.edu:8000/40m/Upgrade_09/RF_System#preview), and DCC under the number T1000461.

  3573   Wed Sep 15 01:27:52 2010 rana, steve, valeraUpdatePSLFSS cables connected

- connected the TTFSS cables (FSS fast goes directly to NPRO PZT for now)

- measured the reference cavity 21.5 MHz EOM drive to be 17.8 dBm

-  turned on the HV for the FSS phase correcting EOM (aka PC) drive

- connected and turned on the reference cavity temperature stabilization

- connected the RefCav TRANS PD

- fine tuned the RefCav REFL PD angle

  3574   Wed Sep 15 01:58:28 2010 valeraUpdatePSLFSS locking

The RefCav is locked and aligned. I changed the fast gain sign by changing the jumper setting on the TTFSS board. The RefCav visibility is 70%. The FSS loop ugf is about 80 kHz (plot attached. there is 10 dB gain in the test point path. this is why the ugf is at 10 dB when measured using in1 and in2 spigots on the front of the board.)  with FSS common gain max out at 30 dB. There is about 250 mW coming out of the laser and 1 mW going to RefCav out of the back of the PMC. So the ugf can be made higher at full power. I have not made any changes to account for the PMC pole (the FSS is after the PMC now). The FSS fast gain was also maxed out at 30 dB to account for the factor of 5 smaller PZT actuation coefficient - it used to be 16 dB according to the (previous) snap shot. The RefCav TRANS PD and camera are aligned. I tuned up the phase of the error signal by putting cables in the LO and PD paths. The maximum response of the mixer output to the fast actuator sweep of the fringe was with about 2 feet of extra cable in the PD leg.

I am leaving the FSS unlocked for the night in case it will start oscillating as the phase margin is not good at this ugf.

Attachment 1: DSC_2510.JPG
DSC_2510.JPG
  3575   Wed Sep 15 03:08:26 2010 KojiUpdatePSLFSS locking

Brilliant! This is the VERY way how the things are to be conquered!

Quote:

The RefCav is locked and aligned. I changed the fast gain sign by changing the jumper setting on the TTFSS board. The RefCav visibility is 70%. The FSS loop ugf is about 80 kHz (plot attached)  with FSS common gain max out at 30 dB. There is about 50 mW coming out of the laser and a few mW going to RefCav out of the back of the PMC. So the ugf can be made higher at full power. I have not made any changes to account for the PMC pole (the FSS is after the PMC now). The FSS fast gain was also maxed out at 30 dB to account for the factor of 5 smaller PZT actuation coefficient - it used to be 16 dB according to the (previous) snap shot. The RefCav TRANS PD and camera are aligned. I tuned up the phase of the error signal by putting cables in the LO and PD paths. The maximum response of the mixer output to the fast actuator sweep of the fringe was with about 2 feet of extra cable in the PD leg.

I am leaving the FSS unlocked for the night in case it will start oscillating as the phase margin is not good at this ugf.

 

  3577   Wed Sep 15 16:00:26 2010 koji, steveUpdateMOPA 

We removed the Lightwave MOPA Controller from 1X1 (south)  It was a real painfully messy job to pull out the umbilical.

Note: the umbilical is shading it plastic cover. It is functional but it has to be taken out side and cleaned. Do not remove it from it's plastic bag in a clean environment.

Now Joe has room for IOO chassy  in this rack.

We also removed the Minco temp controller and ref. cavity ion pump power supply.

 

  3578   Wed Sep 15 16:12:35 2010 koji, steveUpdateMOPAMOPA Controller is taken out of the PSL rack

We removed the Lightwave MOPA Controller, PA#102, NPRO206 power supply to make room for the IOO chassy at 1X1 (south) rack.

The umbilical cord was a real pain to take out. It is shading its plastic cover. The unused Minco was disconnected and removed.

The ref. cavity ion pump controller- power supply was temporarily taken out also.

Attachment 1: P1060843.JPG
P1060843.JPG
  3580   Fri Sep 17 01:36:14 2010 valeraUpdate PMC line width

The attached plots show the PMC cavity line width measurement with 1 mW and 160 mW into the PMC. The two curves on each plot are the PMC transmitted power and the ramp of the fast input of the NPRO. The two measurements are consistent within errors - a few %. The PMC line width  3.5 ms (FWHM) x 4 V / 20 ms (slope of the ramp) x 1.1 MHz / V (NPRO fast actuator calibration from Innolight spec sheet) = 0.77 MHz.

Here is the output of the calculation using Malik Rakhmanov code:

 

modematching =  8.4121e-01

transmission1 =   2.4341e-03

transmission2 =   2.4341e-03

transmission3 =   5.1280e-05

averageLosses =  6.1963e-04

visibility =  7.7439e-01

Here are the inputs for the calculation in the param.m:

 

fw = 0.77e6;                % width of resonance (FWHM) in Hz

Plas = 0.164;                % power into the PMC in W

 

% the following number refer to the in-lock cavity state

 

Pref = 0.037;                % reflected power in W

Ptr = 0.0712;                 % transmitted power in W

Pleak = 0.0015;              % power leaking from back of PMC in W

 

 

Attachment 1: TEK00009.PNG
TEK00009.PNG
Attachment 2: TEK00010.PNG
TEK00010.PNG
  3581   Fri Sep 17 03:06:06 2010 KojiUpdateSUSSOS sent for baking

Two SOS suspensions for the ETMs were disassembled and packed for cleaning and baking by Bob.

These suspensions have been stored on the X end flow bench long years, and looked quite old.

They have some differences to the modern SOSs.

- The top suspension block is made of aluminum and had dog clamps to fix the wires.
- The side bars are not symmetric: the side OSEM can only be fixed at the right bar (left side in the picture).
- EQ stops were made of Viton.
- One of the tower bases seems to have finger prints (of Mike Zucker?).

I found that the OSEM plates had no play. We know that the arrangement of the OSEMs gets quite difficult
in this situation. Therefore the holes of the screws were drilled with the larger drill.

We decided to replace all of the screws to the new ones as all of the screws are Ag plated and got corroded
by silver sulfide (Ag2S). I checked our stock in the clean room. We have enough screws.

Important note: Use stainless screws in aluminum / Silver-plated screws in stainless
There exists some study about galling: LIGO-G020394-00-D

Attachment 1: IMG_3596.jpg
IMG_3596.jpg
Attachment 2: IMG_3597.jpg
IMG_3597.jpg
  3582   Fri Sep 17 03:32:11 2010 KojiUpdateSUSArrangement of the SUS towers

The day before yesterday, I was cleaning a flow bench in the clean room.

I found that one SOS was standing there. It is the SRM suspension.

I thought of the nice idea:

- The installed PRM is actually the SRM (SRMU04). It is 2nd best SRM but not so diiferent form the best one.
==> Use this as the final SRM

- The SRM tower at the clean room
==> Use this as the final PRM tower.
==> The mirror (SRMU03) will be stored in a cabinet.

- The two SOS towers will be baked soon
==> Use them for the ETMs

This reduces the unnecessary maneuver of the suspension towers.

  3583   Fri Sep 17 12:11:42 2010 josephbUpdateCDSDowns update

In doing a re-inventory prior to the IOO chassis installation, I re-discovered we had a missing interface board that goes in an IO chassis.  This board connects the chassis to the computer and lets them talk to each other.  After going to Downs we remembered Alex had taken a possibly broken interface board back to downs for testing. 

Apparently the results of that testing was it was broken.  This was about 2.5 months ago and unfortunately it hadn't been sent back for repairs or a replacement ordered.  Its my fault for not following up on that sooner.

I asked Rolf what the plan for the broken one was.  His response was  they were planning on repairing it, and that he'd have it sent back for repairs today.  My guess the turn around time for that is on the order of 3-4 weeks (based on conversations with Gary), however it could be longer.  This will affect when the last IO chassis (LSC) can be made fully functional.  I did however pickup the 100 foot fiber cable for going between the LSC chassis and the LSC computer (which will be located in 1X3).

As a general piece of information, according to Gary the latest part number for these cards is OSS-SHB-ELB-x4/x8-2.0 and they cost 936 dollars (latest quote).

  3584   Fri Sep 17 14:55:01 2010 josephbUpdateCDSTook 5565 RFM card from IOVME to place in the new IOO chassis

I took the 5565 RFM card out of the IOVME machine to so I could put it in the new IO chassis that will be replacing it.  It is no longer on the RFM network.  This doesn't affect the slow channels associated with the auxilliary crate.

  3585   Fri Sep 17 17:35:35 2010 steveUpdatePEMcleaned up at 1Y1 PSL rack

Cleaned up cables on the top and bottom. Vacuumed both areas. We still have some remaining shading from the MOPA umbilical and more unknown BNC cables hanging around.

  3589   Mon Sep 20 11:39:45 2010 josephbUpdateCDSSwitch over

I talked to with Alex this morning, discussing what he needed to do to have a frame builder running that was compatible with the new front ends.

 

1) We need a heavy duty router as a separate network dedicated to data acquisition running between the front ends and the frame builder.  Alex says they have one over at downs, although a new one may need to be ordered to replace that one.

2) The frame builder is a linux machine (basically we stop using the Sun fb40m and start using the linux fb40m2 directly.).

3) He is currently working on the code today.  Depending on progress today, it might be installable tomorrow.

  3590   Mon Sep 20 16:59:26 2010 josephbUpdateCDSMegatron in 1X2 rack, to be come c1ioo

[Rana, Koji, Joe]

We pulled the phase shifters in the 1X2 rack out to make room for megatron.  Megatron will be converted into c1ioo, and the 8 core, 1U computer will be used as c1lsc.  A temporary ethernet cable was run from 1X2 to 1X3 to connect megatron to the same sub-network.

The c1lsc machine was worked on today, setting it up to run the real time code, along with the correct controls accounts, passwords, .cshrc files, etc.  It needs to be moved from 1X1 to 1X4 tomorrow.

  3593   Tue Sep 21 16:05:21 2010 josephbUpdateCDSFirst pass at rack diagram

I've made a first pass at a rack diagram for the 1X1 and 1X2 racks, attached as png.

Gray is old existing boards, power supplies etc.  Blue is new CDS computers and IO chassis, and gold is for the Alberto's new RF electronics.  I still need to double check on whether some of these boards will be coming out (perhaps the 2U FSS ref board?).

Attachment 1: 1X1_1X2_racks.png
1X1_1X2_racks.png
  3594   Wed Sep 22 16:35:45 2010 josephbUpdateCDSFibers pulled, new FB install tomorrow

[Aidan, Tara, Joe]

We pulled out what used to be the LSC/ASC fiber from the 1Y3 arm rack, and then redirected it to the 1X1 rack.  This will be used as the c1ioo 1PPS timing signal.  So c1ioo is using the old c1iovme fiber for RFM communications back to the bypass switch, and the old LSC fiber for 1PPS.

The c1sus machine will be using the former sosvme fiber for communications to the RFM bypass switch.  It already had a 1 PPS timing fiber.

The c1iscex machine had a new timing fiber already put in, and will be using the c1iscey vme crate's RFM for communication.

We still need to pull up the extra blue fiber which was used to connect c1iscex directly to c1sus, and reuse it as the 1PPS signal to the new front end on the Y arm. 

Alex has said he'll come in tomorrow morning to install the new FB code.

 

  3600   Thu Sep 23 12:05:20 2010 josephb, alexUpdateCDSfb40m down, new fb in progress

Alex came over this morning and we began work on the frame builder change over.  This required fb40m be brought down and disconnected from the RAID array, so the frame builder is not available.

He brought a Netgear switch which we've installed at the top of the 1X7 rack.  This will eventually be connected, via Cat 6 cable, to all the front ends.  It is connected to the new fb machine via a 10G fiber.

Alex has gone back to Downs to pickup a Symmetricon (sp?) card for getting timing information into the frame builder.  He will also be bringing back a harddrive with the necessary framebuilder software to be copied onto the new fb machine.

He said he'd like to also put a Gentoo boot server on the machine.  This boot server will not affect anything at the moment, but its apparently the style the sites are moving towards.  So you have a single boot server, and diskless front end computers, running Gentoo.  However for the moment we are sticking with our current Centos real time kernel (which is still compatible with the new frame builder code).  However this would make a switch over to the new system possible in the future.

At the moment, the RAID array is doing a file system check, and is going slowly while it checks terabytes of data.  We will continue work after lunch. 

 Punchline: things still don't work.

  3602   Thu Sep 23 21:01:11 2010 josephb, alexUpdateCDSfb40m still down, new fb still in progress
Unfortunately, copying the data to the USB/SATA drive over at downs took longer than expected for Alex. We will be installing the new code on the new fb machine tomorrow and running it. We will be running off of a timer on that machine until Monday. On Monday, a Symmetricom card will be arriving from LLO so that we can connect an IRIG-B timing signal into the frame builder and use a proper time signal. There is no running frame builder for tonight and thus will be no trends until we get the new FB running tomorrow morning.
  3604   Fri Sep 24 00:56:35 2010 koji, taraUpdateElectronicstesting TTFSS

We found that a transistor was broken from yesterday spark too. We partially fixed TTFSS, and it should be enough for  testing purpose.

 

From yesterday test, we found that the RF amplifier for LO signal was broken. There was no spare at the electronic shop at Downs,

so we shorted the circuit for now.  Another part which was broken too was a transistor, Q3 PZT2222A, on D0901846.

It was removed and two connections, which are for Q3's 1 and 3 legs, are shorted. Now the voltages out from the regulators are back to normal.

 

We are checking a MAX333A switch, U6A on D0901894. it seems that the voltage that controls the switch disappears.

There might be a bad connection somewhere. This will be investigated next.

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