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ID Date Author Type Category Subject
  2986   Tue May 25 17:22:56 2010 KevinUpdateIOOBeam Profile After Mode Cleaner

Quote:

Very nice as usual. Can you add the curve to show the ideal mode of the MC on the profile plot?

Quote:

I fit the data from the beam profile that Jenne measured on 5/21/2010. The distances are measured from halfway between MC1 and MC3 to the beam scanner. The fits give the following where w0 is the waist size and z0 is the distance from the waist to halfway between MC1 and MC3.

For the horizontal profile:

reduced chi^2 = 0.88

z0 = (1 ± 29) mm

w0 = (1.51 ± 0.01) mm

For the vertical profile:

reduced chi^2 = 0.94

z0 = (673 ± 28) mm

w0 = (1.59 ± 0.01) mm

I calculated the radius of curvature of MC2 using these values of w0:

horizontal: (16.89 ± 0.06) m

vertical:   (17.66 ± 0.07) m

For this calculation, I used the value of (13.546 ± .0005) m for the length of the mode cleaner measured on 6/10/2009. The specification for the radius of curvature of MC2 is (18.4 ± 0.1) m.

Here is the plot with the ideal mode of the mode cleaner shown in brown. The ideal mode was plotted with the radius of curvature of 18.4. The blue curve is the fit to the vertical beam radius, the purple curve is the fit to the horizontal beam radius, * denotes a data point from the vertical data, and + denotes a data point from the horizontal data.

Attachment 1: mcfit.png
mcfit.png
  2985   Tue May 25 17:09:22 2010 KojiUpdateIOOBeam Profile After Mode Cleaner

Very nice as usual. Can you add the curve to show the ideal mode of the MC on the profile plot?

Quote:

I fit the data from the beam profile that Jenne measured on 5/21/2010. The distances are measured from halfway between MC1 and MC3 to the beam scanner. The fits give the following where w0 is the waist size and z0 is the distance from the waist to halfway between MC1 and MC3.

For the horizontal profile:

reduced chi^2 = 0.88

z0 = (1 ± 29) mm

w0 = (1.51 ± 0.01) mm

For the vertical profile:

reduced chi^2 = 0.94

z0 = (673 ± 28) mm

w0 = (1.59 ± 0.01) mm

I calculated the radius of curvature of MC2 using these values of w0:

horizontal: (16.89 ± 0.06) m

vertical:   (17.66 ± 0.07) m

For this calculation, I used the value of (13.546 ± .0005) m for the length of the mode cleaner measured on 6/10/2009. The specification for the radius of curvature of MC2 is (18.4 ± 0.1) m.

 

  2984   Tue May 25 17:04:37 2010 KevinUpdate Beam Profile After Mode Cleaner

I fit the data from the beam profile that Jenne measured on 5/21/2010. The distances are measured from halfway between MC1 and MC3 to the beam scanner. The fits give the following where w0 is the waist size and z0 is the distance from the waist to halfway between MC1 and MC3.

For the horizontal profile:

reduced chi^2 = 0.88

z0 = (1 ± 29) mm

w0 = (1.51 ± 0.01) mm

For the vertical profile:

reduced chi^2 = 0.94

z0 = (673 ± 28) mm

w0 = (1.59 ± 0.01) mm

I calculated the radius of curvature of MC2 using these values of w0:

horizontal: (16.89 ± 0.06) m

vertical:   (17.66 ± 0.07) m

For this calculation, I used the value of (13.546 ± .0005) m for the length of the mode cleaner measured on 6/10/2009. The specification for the radius of curvature of MC2 is (18.4 ± 0.1) m.

In the following plots, the blue curve is the fit to the vertical beam radius, the purple curve is the fit to the horizontal beam radius, * denotes a data point from the vertical data, and + denotes a data point from the horizontal data.

Attachment 1: mcfit.png
mcfit.png
Attachment 2: mcerrors.png
mcerrors.png
  2983   Tue May 25 16:40:27 2010 josephb, alexUpdateCDSFinally tracked down why new models wouldn't talk to each other

The problem with the new models using the new shared memory/dolphin/RFM defined as names in a single .ipc file.

The first is the no_oversampling flag should not be used.  Since we have a single IO processor handling ADCs and DACs at 64k, while the models run at 16k, there is some oversampling occuring.  This was causing problems syncing between the models and the IOP.

It also didn't help I had a typo in two channels which I happened to use as a test case to confirm they were talking.  However, that has been fixed.

  2982   Tue May 25 16:32:26 2010 kiwamuHowToElectronicsfront ends are back

 [Alex, Joe, Kiwamu]

Eventually all the front end computers came back !! 

There were two problems.

(1): C0DCU1 didn't want to come back to the network. After we did several things it turned the ADC board for C0DCU1 didn't work correctly.

(2): C1PEM1 and C0DAQAWG were cross-talking via the back panel of the crate.


(what we did)

* installed a VME crate with single back panel to 1Y6 and mounted C1PEM1 and C0DAQAWG on it. However it turned out this configuration was bad because the two CPUs could cross-talk via the back panel.

* removed the VME crate and then installed another VME crate which has two back panels so that we can electrically separate C1PEM1 and C0DAQAWG.  After this work, C0DAQAWG started working successfully.

 * rebooted all the front ends, fb40m and c1dcuepics.

 * reset the RFM bypath. But these things didn't bring C0DCU1 back.

 * telnet to C0DCU1 and ran "./startup.cmd" manually. In fact "./startup.cmd" should automatically be called when it boots.

 * saw the error messages from "./startup.cmd" and found it failed when initialization of the ADC board. It saids "Init Failure !! could not find ICS"

*  went to 1Y7 rack and checked the ADC. We found C0DCU1 had two ADC boards, one of two was not in used.

* disconnected all two ADCs and put back one which had not been in used. At the same time we changed the switching address of this ADC to have the same address as the other ADC. 

* powered off/on 1Y7 rack. Finally C0DCU1 got back.

* burtrestored the epics to the last Friday, May 21st 6:07am

  2981   Tue May 25 10:06:09 2010 kiwamuUpdateElectronicsbad power supply of a vme rack

 I got a VME crate from Peter's lab. It is already installed in 1Y6 instead of the old broken one.

I checked its power supply, and it looked fine. It successfully supplies +5, +12 and -12 V. And then I put c0daqawg and c1pem1 back from 1Y7.

Now I am trying to reboot all the front end computers with Peter's VME crate. A picture of the VME crate will be updated later.

  2980   Tue May 25 09:12:46 2010 kiwamuConfigurationGreen Lockingeffect from air conditioner

We should completely turn off the air conditioner when working on green locking.

Even if green beams propagates inside of chambers, the air conditioner does affect the spatial jitter of the beam. 

The attached picture was taken when Steve and I were seeing how the green beam jittered. 

At that time the beam was injected from the end table and going through inside of the ETM, the ITM and the BS camber.

Eventually it came out from the camber and hit the wall outside of the chamber. It was obvious, we could see the jittering when the air cond. was ON.

Attachment 1: green_spot.png
green_spot.png
  2979   Tue May 25 07:58:23 2010 kiwamuUpdateelogelog down

I found the elog got down around 7:30 am in this morning.

So I restarted it by running the script: "start-elog-nodus" as instructed on the wiki.

http://lhocds.ligo-wa.caltech.edu:8000/40m/How_To/Restart_the_elog

  2978   Tue May 25 07:22:59 2010 kiwamuUpdateElectronicsbad power supply of a vme rack

Notes on May 25th

 Don't do the following things !! This causes bad cross-talking of CPUs mounted on the crate.

 


I moved c0daqawg and c1pem1 from 1Y6 vme crate to 1Y7 crate due to the bad power supply.

Another problem: c0dcu1 doesn't come back to the network. 

After moving them, I tried to get back them into the RFM network. However  c0dcu1 never came back, it still indicates red in C0DAQ_DETAIL.adl screen.

Alberto and I did even "nuclear option" (as instructed), but no luck.

  2977   Tue May 25 00:10:24 2010 ZachUpdateIOOIMC table leveled again

The IMC table had to be leveled again, for two reasons: 1) It was un-leveled when Jenne and Kiwamu removed an extra beam dump when they took the beam profile measurements, and 2) the stack of weights I had put there before was too tall to allow the beam to pass (I didn't realize that the BS chamber is offset a bit to the north, so the beam passes right over the NE edge of the IMC table).

First of all, I was wrong before when I said that the stack of weights was 4 blocks tall; it was 6 blocks tall. I re-leveled the table this afternoon by removing the top three blocks and placing them immediately south of the bottom three in the original stack, while also moving the circular weight north of its previous position. The table is now balanced roughly to within the tolerance of the bubble level I was using.

After the leveling, I tried to re-lock the modecleaner. Upon removing the beam block on the PSL table, I got some sort of resonance flashes on the MC TRANS monitor. With some minor adjustments to MC2&3, I was able to get a decent TEM00 mode to hit. The cavity wouldn't lock, so I went to the AP table and checked to make sure that the REFL beam was hitting the PD. It was, but the beam was very close to the edge of the focusing lens, so I moved the steering mirror slightly to make the situation a little better.

I then went to the control room to finish the by-now-mundane task of fine-tuning the MC lock, but today's was a worthier opponent. For some reason, the thing didn't want to lock for more than a few seconds at a time. I saw that the spot on MC2 was quite a bit off-center, so I ran the MC2_spot_xxx scripts to get it visually in place, then revisited the AP table to ensure that the REFL beam was still on the PD. No dice.

I don't know what was different. I had Ameristat over the opening between the tanks, with posters on top and on the sides (as usual), and I checked to ensure that the servo gains were at the appropriate levels. Joe pointed out that IOO VME was not responding, but we didn't seem to think that this was the problem (based on nothing I can put in words or stick figure cartoons), and the "alive" indicator on the Auto-Lock control in the MEDM screen was not blinking, as it usually is, but I don't know what bearing this has on anything.

I will try to lock again tomorrow.

 

  2976   Mon May 24 16:34:22 2010 KevinUpdatePSLND Filters for 2W Beam Profile

I tried to measure the beam profile of the 2W laser today but ran into problems with the ND filters. With the measurements I made a few weeks ago, I used a reflective ND 4.0 filter on the PD. The PD started to saturate and Koji and I noticed that a lot of the metallic coating on the filter had been burnt off. Koji told me to use an absorptive ND 4.0 filter in front of a reflective ND 0.6 filter. I tried this today but noticed that a few holes were being burned into the absorptive filter and that the coating on the reflective filter behind it was also being burned off in spots. I don't think we wanted to use a polarizing beam splitter to reduce the power before the PD but I didn't want to ruin any more filters.

  2975   Mon May 24 14:28:35 2010 kiwamuUpdateElectronicsbad power supply of a vme rack

In this morning I found daqawg didn't work.

After looking for the cause, I found one of the vme racks mounted on 1Y6 doesn't work correctly.

It looks like the vme rack mounting c0daqawg could not supply any power to the frontends.

 

Now Steve and I are trying to look for a spare for it.

  2974   Mon May 24 11:32:05 2010 ranaUpdateLSC40mUpgrade Field Power and RF Power Spectrum at the ports. 38m/38.55m arm length issue.

Quote:

 

 If you have a working 40m Optickle model, put it in a common place in the SVN, not in your own folder.

I can't figure out why changing the arm length would effect the RF sidebands levels. If you are getting RF sidebands resonating in the arms, then some parameter is not set correctly.

As the RF sideband frequency gets closer to resonating in the arm, the CARM/DARM cross-coupling to the short DOFs probably gets bigger.

I uploaded the latest iscmodeling package to the SVN under /trunk. It includes my addition of the 40m Upgrade model: /trunk/iscmodeling/looptickle/config40m/opt40mUpgrade2010.m.

I don't know the causes of this supposed resonances yet. I'm working  to try to understand that. It would be interesting also to evaluate the results of absolute length measurements.

Here is what I also found:

reflRFpowerVsArmLength.png

It seems that 44, 66 and 110 are resonating.

If that is real, than 37.5m could be a better place. Although I don't have a definition of "better" yet.  All I can say is these resonances are smaller there.

  2973   Mon May 24 10:03:14 2010 ranaUpdateLSC40mUpgrade Field Power and RF Power Spectrum at the ports. 38m/38.55m arm length issue.

 

 If you have a working 40m Optickle model, put it in a common place in the SVN, not in your own folder.

I can't figure out why changing the arm length would effect the RF sidebands levels. If you are getting RF sidebands resonating in the arms, then some parameter is not set correctly.

As the RF sideband frequency gets closer to resonating in the arm, the CARM/DARM cross-coupling to the short DOFs probably gets bigger.

  2972   Mon May 24 07:53:57 2010 steveConfigurationPEMair cond. just turned ON

IFO room temp 27.5C , Please remember to turn AC back on !

Attachment 1: acoff.jpg
acoff.jpg
  2971   Fri May 21 16:41:38 2010 Alberto, JoUpdateComputersIt's a boy!

Today the new Dell computer for the GSCS (General SURF Computing Side) arrived.

We put it together and hooked it up to a monitor. And guess what? It works!

I'm totally impressed by how the Windows get blurred on Windows 7 when you move them around. Good job Microsoft! Totally worth 5 years of R&D.

  2970   Fri May 21 16:37:35 2010 steveConfigurationVACtp3's drypump replaced

Bob replaced the tipseal in an other drypump and I swapped it in. TP3 turbo is running again, it's foreline pressure is 40 mTorr. The RGA is still off

  2969   Fri May 21 16:27:45 2010 AlbertoOmnistructureEnvironmentThe control room is molding...

... not just because we haven't locked the interferometer for quite some time. I mean, it literally stinks. The chiller's chiller is molding. Its' dripping water and there's mold all under it (Jo just confirmed: "yeah, it's mold").

Someone from Caltech maintenance just crossed the door. Hopefully he'll help us fix it.

I'll keep you updated. Stay tuned.

  2968   Fri May 21 16:24:11 2010 KojiUpdateLSC40mUpgrade Field Power and RF Power Spectrum at the ports. 38m/38.55m arm length issue.

1. Give us the designed arm length. What is the criteria?

2. The arm lengths got shorter as the ITMs had to shift to the end. To make them longer is difficult. Try possible shorter length.

  2967   Fri May 21 14:31:46 2010 josephb,alexUpdateCDSNew computer and IO chassis working in 1X4

Alex brought over a ADC, DAC, and PCIe card which goes into the computer and talk to the IO chassis.  We tried installing the new "small" IO chassis in 1X4, but initially it couldn't find the ADC/DAC boards, just the Contec Binary out board.

We tried several different configurations (different computer, different IO chassis, the megatron chassis, the megatron IO chassis with new cards, a new IO chassis with megatron cards.

The two things were concluded once we got a new IO chassis talking with the new computer. 

1) Its possible one of the slots is in the IO chassis as we didn't see the ADC until we moved it to a different slot in the new chassis

2) The card that Alex had brought over to put in the computer doesn't behave well with these IO chassis.  He went back to downs to try and figure out what it is, and test it with the chassis over there.

Currently, Megatron's IO chassis is sitting on a table behind racks 1Y5 and 1Y6, along with the new "large" IO chassis.  Megatron's PCIe card for talking to the IO chassis was moved to the computer in 1X4.  The computer in 1X4 is currently being called c1iscex with IP 192.168.113.80. 

  2966   Fri May 21 11:56:34 2010 AlbertoUpdate40m Upgrading40mUpgrade Field Power and RF Power Spectrum at the ports. 38m/38.55m arm length issue.

I update my old 40mUpgrade Optickle model, by adding the latest updates in the optical layout (mirror distances, main optics transmissivities, folding mirror transmissivities, etc). I also cleaned it from a lot of useless, Advanced LIGO features.

I calculated the expected power in the fields present at the main ports of the interferometer.

I repeated the calculations for both the arms-locked/arms-unlocked configurations. I used a new set of functions that I wrote which let me evaluate the field power and RF power anywhere in the IFO. (all in my SVN directory)

As in Koji's optical layout, I set the arm length to 38m and I found that at the SP port there was much more power that I woud expect at 44Mhz and 110 MHz.

It's not straightforward to identify unequivocally what is causing it (I have about 100 frequencies going around in the IFO), but presumably the measured power at 44MHz was from the beat between f1 an f2 (55-11=44MHz), and that at 110MHz was from the f2 first sidebands.

Here's what i found:

RFPower_locked_38m.png

RFPower_unlocked_38m.png

FieldPower_locked_38m.png

FieldPower_unlocked_38m.png

 

I found that When I set the arm length to 38.55m (the old 40m average arm length), the power at 44 and 110 MHz went significantly down. See here:

RFPower_3855m.png

 FieldPower_3855m.png

I checked the distances between all the frequencies circulating in the IFO from the closest arm resonance to them.

I found that the f2 and 2*f2 are two of the closest frequencies to the arm resonance (~80KHz). With a arm cavity finesse of 450, that shouldn't be a problem, though.

40mUpgrade_distanceFromResonance_38m.png

 I'll keep using the numbers I got to nail down the culprit.

Anyways, now the question is: what is the design length of the arms? Because if it is really 38m rather than 38.55m, then maybe we should change it back to the old values.

  2965   Fri May 21 08:28:29 2010 steveConfigurationVACTP3 turned off

Quote:

[Jenne, Kiwamu, and Steve via phone]

Around 9:30pm, Kiwamu and I came back from dinner, and were getting ready to begin the beam scan measurements.  I noticed that one of the vacuum pumps was being very loud.  Kiwamu noted that it is the fore pump for TP3's turbo, which he and Steve replaced in January (elog 2538).  We had not noticed these noises before leaving for dinner, around 8pm.

We called Steve at home, and he could hear the noise through the phone. He said that even though it was really loud, since it was reading 3.3mTorr (on the display of the controller, in the vacuum rack just above head-height) which is close to the nominal value, it should be fine to leave.  He will check it out in the morning.  If it had been reading at or above ~1Torr, that's indicative of it being really bad, and we would have needed to shut it off.

For future reference, in case we need to turn it off, Steve said to use the following procedure:

1. Close VM3, to isolate the RGA, which is what this pump is currently (while we're at atmosphere) pumping on.  I don't know if there are other things which would need to be shut at this stage, if we were at vacuum nominal.

2. Close VM5, which is right in front of TP3, so TP3's pump is just pumping on itself.

3. Push the "Stop" button on the Turbo controller for TP3, in the vacuum rack, about waist level.  Turning off the turbo will also turn off the fore pump.

UPDATE, 1am: The controller in the rack is reading 3.1mTorr, so the pump, while still noisy, still seems to be working.

 The foreline pressure of TP3 is 2.9 mTorr  The drypump is loosing it's bearing and it is very noisy.

V3, V5 closed and TP3 small turbo controller off. This turned off the noisy forepump that has to be replaced.

RGA is running at cc4 2e-6 Torr

The RGA was turned off at cc4 1e-5 Torr

  2964   Fri May 21 00:51:06 2010 JenneUpdateIOOFirst MC mode measuring (hopefully) done

[Jenne, Kiwamu, Steve]

Round 1 of measuring the MC mode is pretty much done.  Yay.

Earlier today, Steve and I launched the MC beam off the flat mirror just after the Faraday, and sent it down toward ETMY(new convention). We ended up not being able to see it all the way at the ETM because we were hitting the beam tube, but at the ITM chamber we could see that the beam looked nice and circle-y, so wasn't being clipped in the Faraday or anywhere else.  To do this we removed 2 1inch oplev optics.  One was removed from the BS table, and wrapped in foil and put in a plastic box.  The other was just layed on its' side on the BS table. 

I then took the beam out of the BS chamber, in order to begin measuring the mode.  I left the flat fixed mirror in the place of what will be PZT SM1, and instead used the PZT mirror to turn the beam and get it out the BS chamber door.  (Thoughts of getting the beam to the BS oplev table were abandoned since this was way easier, since Kiwamu and Steve had made the nifty table leg things.)  Kiwamu and I borrowed an 2inch 45P Y1 optic from the collection on Koji's desk (since we have ZERO 2inch optics on the random-optic-shelf....no good), to shoot the beam down the hallway of the Yarm (new convention).  We used the beam scan on a rolling cart to measure the beam at various distances.  I made some sweet impromptu plum bobs to help make our distance measurements a bit more accurate.

We stopped at ~25 feet from the BS chamber, since the spot was getting too big for the beam scanner.  If it turns out that I can't get a good fit with the points I have, I'll keep everything in-chamber the same, and do the farther distances using the good ol' razor blade technique.

I have measurements for the distances between the beam scan head and the opening of the BS chamber.  Tomorrow, or very soon after, I need to measure the distances in-chamber between the MC and the BS chamber opening.  Plots etc will come after I have those distances.

Next on the to-do list:

1.  Measure distances in-chamber for first mode scan.

2.  Plot spot size vs. distance, see if we need more points. Take more points if needed.

3.  Put in MMT1, repeat measurements.

4.  Put in MMT2, rinse and repeat.

5.  Move the PZT mirror to its new place as SM1, and figure out how to connect it.  Right now the little wires are hooked up on the BS table, but we're going to need to make / find a connector to the outside world from the IOO table. This is potentially a pretty big pain, if we don't by happenstance have open connectors on the IOO table.

  2963   Fri May 21 00:30:44 2010 JenneUpdateVACTP3 fore pump is very loud

[Jenne, Kiwamu, and Steve via phone]

Around 9:30pm, Kiwamu and I came back from dinner, and were getting ready to begin the beam scan measurements.  I noticed that one of the vacuum pumps was being very loud.  Kiwamu noted that it is the fore pump for TP3's turbo, which he and Steve replaced in January (elog 2538).  We had not noticed these noises before leaving for dinner, around 8pm.

We called Steve at home, and he could hear the noise through the phone. He said that even though it was really loud, since it was reading 3.3mTorr (on the display of the controller, in the vacuum rack just above head-height) which is close to the nominal value, it should be fine to leave.  He will check it out in the morning.  If it had been reading at or above ~1Torr, that's indicative of it being really bad, and we would have needed to shut it off.

For future reference, in case we need to turn it off, Steve said to use the following procedure:

1. Close VM3, to isolate the RGA, which is what this pump is currently (while we're at atmosphere) pumping on.  I don't know if there are other things which would need to be shut at this stage, if we were at vacuum nominal.

2. Close VM5, which is right in front of TP3, so TP3's pump is just pumping on itself.

3. Push the "Stop" button on the Turbo controller for TP3, in the vacuum rack, about waist level.  Turning off the turbo will also turn off the fore pump.

UPDATE, 1am: The controller in the rack is reading 3.1mTorr, so the pump, while still noisy, still seems to be working.

  2962   Fri May 21 00:21:24 2010 JenneUpdateSAFETYDon't walk down the Y(new convention) arm tonight!

All clear.

Quote:

Please don't go down the Yarm (Old Xarm) for right now, or if you do, please be very careful.  Kiwamu and I are set up to take beam scan measurements down the walkway, and so there are some cables / carts / other stuff down there.  We are going to get dinner really quickly before beginning the measurements. 

Right now, the PSL shutter is Closed, so there is no beam hazard outside of the chambers, just crowded space hazard.

 

  2961   Thu May 20 20:03:37 2010 JenneUpdateSAFETYDon't walk down the Y(new convention) arm tonight!

Please don't go down the Yarm (Old Xarm) for right now, or if you do, please be very careful.  Kiwamu and I are set up to take beam scan measurements down the walkway, and so there are some cables / carts / other stuff down there.  We are going to get dinner really quickly before beginning the measurements. 

Right now, the PSL shutter is Closed, so there is no beam hazard outside of the chambers, just crowded space hazard.

  2960   Thu May 20 14:18:59 2010 kiwamuUpdateGreen Lockingmode profile of 40m cavity

The mode profile of the green beam going through 40m cavity was measured.

According to the fitting the coupling efficiency to the cavity is 98.46%, but still the beam looks loosely focused.

This measurement has been done by using the oplev legs (entry #2957) to allow the beam to go through the 40m walkway.

With a beam scan set on a movable cabinet, I measured it along the 40m chamber.

Since the plot looks not so nice,  I am going to work on this measurement a little bit more after I improve the mode matching.

 


Here is the parameters from the fitting

target waist [mm] 2.662
measured waist x [mm] 2.839
measured waist x [mm] 3.111
   
target waist position [m] 43.498
measured waist position x [m] 42.579
measured waist position y [m] 38.351

 

I believe the error for the travel length was within 0.5 meter. The length was always measured by a tape measure.

A thing I found was that: spatial jittering of the beam gets bigger as the beam goes further. This is the main source of the error bar for the spot size. 

 

 

Attachment 1: MMT40mcavity.png
MMT40mcavity.png
  2959   Thu May 20 13:29:40 2010 kiwamuUpdateGreen Lockingmode profile at PPKTP crystal

 I measured again the mode profile of the beam going through the PPKTP crystal by using the beam scan.

The aimed beam waist is 50 um (as described in entry 2735),

and the measured profile had pretty good waist of wx=51.36 +/- 0.0999 um and wy=49.5 +/- 0.146 um 

The next things I have to do are - (1). re-optimization of the temperature of the crystal (2). measurement of the conversion efficiency

The attached figure is the result of the measurement. 

Attachment 1: PPKTPmode.png
PPKTPmode.png
  2958   Thu May 20 13:12:28 2010 josephbUpdateCDSPreparations for testing lsc,lsp, scy,spy together

In /cvs/cds/caltech/target/fb modified:

master: cleaned up so only io1 (IO processor), LSC, LSP, SCY, SPY were listed, along with their associated tpchan files.

daqdrc: fixed "dcu_rate 9 = 32768" to "dcu_rate 9 = 65536" (since the IO processor is running at 64k)

Added "dcu_rate 21 = 16384" and "dcu_rate 22 = 16384"

Changed "set gds_server = "megatron" "megatron" "megatron" 9 "megatron" 10 "megatron" 11;" to

set gds_server = "megatron" "megatron" 9 9;

The above change was made after reading Rolf's Admin guide: http://lhocds.ligo-wa.caltech.edu:8000/40m/Upgrade_09/CDS?action=AttachFile&do=get&target=RCG_admin_guide.pdf
The set gds_server is simply telling which computer the gds daemons are running on, and we don't need to do it 5 times.


In /cvs/cds/caltech/gds/params modified:

testpoint.par: added C-node7 and C-node8 for SCY and SPY respectively.

  2957   Thu May 20 12:34:46 2010 kiwamuConfiguration40m Upgradingoptical breadboards with legs

Yesterday Steve and I revived two legs to mount some optical breadboards outside of the end table.

These legs had been used as oplev's mounts many years ago, but now they are served for 40m upgrading. These are really nice.

By putting them on the side of the end table, a mirror mounted on the top of the leg can reflect the beam outside of the end table.

Once we pick off the green beam from the end table to its outside, the green beam can propagate through the 40m walkway along the Y-arm.

So that we can measure the beam profile as it propagates.

These legs are also going to be used during mode matching of the vacuum optics.

Attachment 1: leg1_small.png
leg1_small.png
Attachment 2: leg2_small.png
leg2_small.png
  2956   Thu May 20 12:10:44 2010 kiwamuUpdatePhotosETMY end table

 I updated the photo of ETMY end table on the wiki.

http://lhocds.ligo-wa.caltech.edu:8000/40m/Optical_Tables

Attachment 1: ETMY_s.png
ETMY_s.png
  2955   Thu May 20 10:06:56 2010 AidanHowToPhase CameraPhase Camera- raw data video


 

  2954   Wed May 19 22:28:05 2010 KojiUpdateIOOHooray! We locked the MC! (and some other stuff)

Good! What was the key?

The MC2 spot looks very high, but don't believe the TV image. Believe the result of script/A2L/A2L_MC2. What you are looking at is the comparison of the spot at the front surface and the OSEMs behind the mirror.

Quote:

[Jenne, Kevin]

We opened up the MC chambers again, and successfully got the MC locked today!  Hooray!  This meant that we could start doing other stuff....

First, we clamped the Faraday.  I used the dog clamps that Zach left wrapped in foil on the clean cart.  I checked with a card, and we were still getting the 00 mode through, and I couldn't see any clipping.  2 thumbs up to that.

Then we removed the weight that was on the OMC table, in the way of where MMT2 needs to go.  We checked the alignment of the MC, and it still locks on TEM00, but the spot looks pretty high on MC2 (looking at the TV view). We're going to have to relevel the table when we've got the MMT2 optic in the correct place.

We were going to start moving the PZT steering mirror from the BS table to the IOO table, place MMT2 on the OMC table, and put in a flat mirror on the BS table to get the beam out to the BS oplev table, but Steve kicked us out of the chambers because the particle count got crazy high.  It was ~25,000 which is way too high to be working in the chambers (according to Steve).  So we closed up for the day, and we'll carry on tomorrow.  

Photos of the weight before we removed it from the OMC table, and a few pictures of the PZT connectors are on Picasa

 

  2953   Wed May 19 16:09:11 2010 josephbUpdateCDSRacks to small for IO Chassis rails

So I discovered the hard way that the racks are not standard width, when I was unable to place a new IO chassis into the racks with rails attached.  The IO chassis is narrow enough to fit through without the rails however. 

I've talked to Steve and we decided on having some shelves made.  I've asked Steve to get us 6.  1 for each end (2), 1 for SUS, 1 for LSC, 1 for IO, and 1 extra.

  2952   Wed May 19 16:00:18 2010 JenneUpdateIOOHooray! We locked the MC! (and some other stuff)

[Jenne, Kevin]

We opened up the MC chambers again, and successfully got the MC locked today!  Hooray!  This meant that we could start doing other stuff....

First, we clamped the Faraday.  I used the dog clamps that Zach left wrapped in foil on the clean cart.  I checked with a card, and we were still getting the 00 mode through, and I couldn't see any clipping.  2 thumbs up to that.

Then we removed the weight that was on the OMC table, in the way of where MMT2 needs to go.  We checked the alignment of the MC, and it still locks on TEM00, but the spot looks pretty high on MC2 (looking at the TV view). We're going to have to relevel the table when we've got the MMT2 optic in the correct place.

We were going to start moving the PZT steering mirror from the BS table to the IOO table, place MMT2 on the OMC table, and put in a flat mirror on the BS table to get the beam out to the BS oplev table, but Steve kicked us out of the chambers because the particle count got crazy high.  It was ~25,000 which is way too high to be working in the chambers (according to Steve).  So we closed up for the day, and we'll carry on tomorrow. 

 

Photos of the weight before we removed it from the OMC table, and a few pictures of the PZT connectors are on Picasa

  2951   Wed May 19 14:36:46 2010 AidanHowToPhase CameraPhase Camera algorithm and stuff

 I had a think about the algorithm we might use for the phase camera measurement. MATLAB has an fft function that will allow us to extract the data that we need with a single command.

We record a series of images from a camera and put them into a 3D array or movie, image_arr, where the array parameters are [x-position, y-position, time], i.e. a 2D slice is a single frame from the camera. Then we can do an FFT on that object with the syntax, f3D = fft(image_arr, [ ], 3), which only does the FFT on the temporal components. The resulting object is a 3D array where each 2D slice is an 2D array of amplitude and phase information across the image for a single temporal frequency of the movie.

So if we recorded a movie for 1s where the sample rate is 58Hz, then the 1st frame of f3D is just a DC image of the movie, the 2nd frame are the complex 1Hz components of the movie, etc all the way up to 29Hz. 

Suppose then that we have a image, part of which is being modulated, e.g. a chopper wheel rotating at 20 or 24Hz, or a laser beam profile which contains a 1kHz beat between a sideband and a reference beam. All we have to do is sample at at least twice that modulation frequency, run the command in MATLAB, and then we immediately get an image which contains the phase and magnitude information that we're interested in (in the appropriate 2D slice o the FFT).

As an example, I recorded 58 frames of data from a camera, sampling at 58Hz, which was looking at a spinning chopper wheel. There was a white sheet of paper behind the wheel which was illuminated from behind by a flashlight. The outer ring was chopping at 24Hz and the inner ring was chopping at 20Hz. I stuck all the images into the 3D array in MATLAB, did the transformation and picked out the DC, 20Hz and 24Hz signals. The results are shown in the attached PDFs which are:

  1. phase_camera_DC_comp.pdf - a single image from the camera and the DC component (zoomed in) of the FFT
  2. phase_camera_F1_comp.pdf - the magnitude and phase information of the 20Hz component of the FFT
  3. phase_camera_F2_comp.pdf - the magnitude and phase information of the 24Hz component of the FFT (this PDF contains a typo that says 25Hz).
  4. load_raw_data.m - the MATLAB routine that loads the saved data from the camera and does the FFT

You can, and I have, run the MATLAB engine from C directly. This will allow you to transfer the data from the camera to MATLAB directly in memory, rather than via the disk, but it does need proper memory allocation to avoid segmentation faults - that was too frustrating for me in the short term. In this case, the 58 frames were recorded to a file as a contiguous block of data which I then loaded into MATLAB, so it was slower than it might've otherwise been. Also the computer I was running this on was a bit of a clunker so it took a bit of time to do the FFT.

The data rate from the camera was 58fps x (1024 x 1024) pixels per frame x 2 bytes per pixel = 116MB per second. If we were to use this technique in a LIGO phase camera, where we want to measure a modulation which is around 1kHz, then we'd need a sample rate of at least 2kHz, so we're looking at at least a 30x reduction in the resolution. This is okay though - the original phase camera had only ~4000 spatial samples. So we could use, for instance, the Dalsa Falcon VGA300 HG which can give 2000 frames per second when the region of interest is limited to 64 pixels high.

Attachment 1: phase_camera_DC_comp.pdf
phase_camera_DC_comp.pdf
Attachment 2: phase_camera_F1_comp.pdf
phase_camera_F1_comp.pdf
Attachment 3: phase_camera_F2_comp.pdf
phase_camera_F2_comp.pdf
Attachment 4: load_raw_data.m
% load a raw data file into MATLAB

fid = fopen('phase_camera_data.dat');
n1 = 750;
A3D = ones(n1, n1, 58);

for jj = 1:58
    A = fread(fid, [1024, 1024], 'uint16');
    A3D(:,:,jj) = A((512-floor(n1/2)):(512-floor(n1/2))+n1-1, ...
                    (512-floor(n1/2)):(512-floor(n1/2))+n1-1);
... 64 more lines ...
  2950   Tue May 18 23:03:08 2010 JenneUpdateIOONo real progress....

[Jenne, Kevin]

No real progress today.  We opened the chambers and again tried to lock the MC.  Gave up after ~2.5 hours (and closed up the chambers with light doors, replaced manual beam block, etc...).  With Koji's helpful coaching, hopefully we'll finally get it done tomorrow.  Then we can move forward with the actual to-do list. 

 

  2949   Tue May 18 16:44:35 2010 KojiUpdateIOOFirst steps toward MC mode measuring

Here is the upadted list http://lhocds.ligo-wa.caltech.edu:8000/40m/Upgrade_09/Optics

Quote:

I will update how the mirrors should be migrated from the table to the table. 

 

  2948   Tue May 18 16:19:19 2010 josephbUpdateCDSWe have two new IO chassis

We have 2 new IO chassis with mounting rails and necessary boards for communicating to the computers.  Still need boards to talk to the ADCs, DACs, etc, but its a start.  These two IO chassis are currently in the lab, but not in their racks.

They will installed into 1X4 and 1Y5 tomorrow.  In addition to the boards, we need some cables, and the computers need the approriate real time operating systems setup.  I'm hoping to get Alex over sometime this week to help work on that.

  2947   Tue May 18 15:09:02 2010 steveConfigurationSAFETYPSL output shutter in order again

Quote:

As we learned yesterday, the PSL laser power out put mechanical shutter is not working in the remote mode. It only works in local manual mode.

Do not rely on the MEDM screen monitor readout! The position is only changing on the monitor. The main beam must be blocked before the output periscope.

Ben found the Sorenson 5V ps off. It was turned off since our last scheduled power outage. I wonder what else is running on 5V in the PSL? This power supply should be on the

"alarm handler"  list to avoid future repeat of this condition. However a real safety switch would have confirming position sensors of the shutter open or closed. Is there such thing at the sites?

  2946   Tue May 18 14:30:31 2010 josephbUpdateCDSLSC.mdl problem found and fixed

After having checked old possibilities and deciding I wasn't imagining the lsc.mdl file not working, but working as another name, I tracked Alex down and asked for help.

After scratching our heads, we finally tracked it down to the RCG code itself, as opposed to any existing code.

Apparently, the skeleton.st file (located in /home/controls/cds/advLigoRTS/src/epics/util/) has special additional behavior for models with the following names: lsc, asc, hepi, hepia, asc40m, ascmc, tchsh1, tchsh2.

Alex was unsure what this additional code was for.  To disable it, we went into the skeleton.st file, and changed the name "SEQUENCER_NAME_lsc" to "SEQUENCER_NAME_lsc_removed" where ever it occured.  These names were in #ifdef statements, so now these codes will only be used if the model is named lsc_removed.  This apparently fixed the problem.  Running startlsc now runs the code as it should, and I can proceed to testing the communication to the lsp model.

Alex said he'd try to figure out what these special #ifdef code pieces are intended for and hopefully completely remove them once we've determined we don't need it.

  2945   Tue May 18 12:04:13 2010 robUpdateIOOFirst steps toward MC mode measuring

Quote:

Another note: Don't trust the PSL shutter and the switch on the MEDM screens! Always use a manual block in addition!!! We discovered upon closeup that hitting the "Closed" button, while it reads back as if the shutter is closed (with the red box around the buttons), does not in fact close the shutter.  The shutter is still wide open.  This must be fixed.

 Has anyone tried pushing the "reset" button on the Uniblitz driver?

  2943   Tue May 18 11:54:29 2010 steveConfigurationSAFETYpsl mechanical shutter is not working

As we learned yesterday, the PSL laser power out put mechanical shutter is not working in the remote mode. It only works in local manual mode.

Do not rely on the MEDM screen monitor readout! The position is only changing on the monitor. The main beam must be blocked before the output periscope.

  2942   Tue May 18 01:40:56 2010 KojiUpdateIOOFirst steps toward MC mode measuring

OK. Don't worry. This is just an initial confusion which we also had for the suspensions a while ago.

The faraday must be clamped. It shakes the table terribly but it is fine. The leveling may change a bit but should be small enough. Otherwise, just tweak the weights. In fact, the faraday has enough large apertures and we hope we don't need to move it again, as far as the MC incident beam is not moved. But if necessary, we don't move the mirrors but move the faraday itself.

Usually the alignment of the MC is taken by MC2/MC3 such that we don't  move the refl. But if you think what have moved is the MC1/MC3 (i.e. activity in the IMC chamber), take the alignment of the MC1/MC3.

It is just a matter of time to get TEM00. If you get TEM11, it is already close. If you align for TEM11, it is enough aligned to lock TEM10 or TEM01. Once you got better mode, align for it again. Eventually you will get TEM00.

The leveling may change by moving the optics and the weight again. But once the leveling is recovered by arranging the weights somewhere else,
the pointing must be fine again. If necessary, You can remove two optics for squeezing injection (strange motorized rotating mirror and a mount sticking out from the table to south.)

Yes, we need to move the PZT mirror. For the connection, only Steve can give us the right way to do it. If it is too much hussle, just move only the mirror and ignore the wiring for now.

I will update how the mirrors should be migrated from the table to the table.

 

  2941   Mon May 17 19:42:11 2010 JenneUpdateIOOFirst steps toward MC mode measuring

[Jenne, Kevin, Steve]

We made some progress toward getting the MC's beam profile measured.  In the end, no changes were made to anything today, but we're more prepared to go for tomorrow.

What we did:

* Grabbed the scanning slit beam scan from the PSL lab.  It's the same kind as we had here at the 40m, so Kevin was able to hook it up to the computer, and confirmed that it works.

* Opened the IOO and OMC chamber doors, and locked the MC.  Unfortunately the MC mode was awful in Yaw.  Awful like TEM(0,10+). But it still locked.  

* Confirmed that the beam went through the Faraday.  I looked at the beam before and after the Faraday on a card, and it was the same nasty beam both before and after.  So it looks like Zach did a good job aligning the Faraday and everything else.  I was going to clamp the Faraday, but I didn't yet, since I wanted to see the nice happy TEM00 mode go through without clipping before risking moving the Faraday during clamping (I don't know how heavy it is, so I'm not sure how much it might potentially move during clamping.)

* Noticed that there is a whole lot of crap on both the OMC and BS tables that's going to have to move.  In particular, one of the weights leveling the OMC table is right where I need to put MMT2.  Steve suggested putting the optic there, in its approximate place, before doing too much other stuff, since it could potentially affect the leveling of the table, and thus the input pointing to the MC.  Unfortunately, to do that I'll need to move the weight, which is definitely going to change things.  Sad face.  Moving the weight will likely be one of the first things I do tomorrow, so that all 3 profile measurements have the same configuration. 

* Before closing up, I tried to align the MC, to get back to TEM00, to no avail.  I got as far as achieving TEM11 flashing, along with a bunch of other crappy modes, but didn't get 00.  That's also on the to-do list.

What we're going to do:

* Open the chambers, and align the MC to TEM00 (using the sliders on the MC align screen).

* Check with an IR card that the beam goes through the Faraday.

* Clamp the Faraday, reconfirm.

* Remove the weight on the OMC table.

* Place MMT2 on the OMC table in it's approximate final location.

* Realign the MC, and make sure the beam goes through the Faraday.  If this doesn't happen smoothly, I may need more instruction since I've never dealt with aligning the Faraday before.  What are the appropriate mirrors to adjust? 

* Move the PZT flat steering mirror from the BS table to the IOO table.  (Thoughts on this?  This will change the table leveling, and also includes the trickiness of needing to move the connectors for the PZT.)

* Place a flat mirror on the BS table to route the MC beam out to the BS/PRM/SRM oplev table. 

* Measure the mode using the beam scan: on the BS oplev table, on the POX table, and then perhaps by shooting the beam through the beamtube on the ETMY (new convention) table.

* Place MMT1 on the BS table, use flat mirrors to get it out of the chambers, repeat measurements.

* Place MMT2 in the correct position, use flat mirrors to get it out of the chambers, repeat measurements.

All of this may require some serious cleaning-up of the BS table, which is going to be ugly, but it has to happen sometime. Hopefully I can get away with only moving a minimal number of things, in order to get these measurements done.

 

Another note: Don't trust the PSL shutter and the switch on the MEDM screens! Always use a manual block in addition!!! We discovered upon closeup that hitting the "Closed" button, while it reads back as if the shutter is closed (with the red box around the buttons), does not in fact close the shutter.  The shutter is still wide open.  This must be fixed.

  2940   Mon May 17 17:17:49 2010 josephb, steve, alberto, kiwamuUpdateCDSNew CDS computers now in racks.

We placed 3 new computers in the racks.  One in 1X4 (machine running SCX) and 2 in 1Y4 (LSC and SUS).  These are 1U chassis, 4 core machines for the CDS upgrade.  I will be bringing over 2 IO chassis and their rails over tomorrow, one to be placed in 1Y4, and 1 in 1X4.

We still need some more 40 pin adapter cables and will send someone over this week to make them.  However, once we have those, we should be able to get two to three machines going, one end computer/chassis and the SUS computer/chassis.

After tomorrow we are still going to be owed 1 computer, another dolphin fiber, a couple of blue boxes, and the LSC, IO, and Y end IO chassis.  We also realized we need further fiber for the timing system.  We're going to need to get and then run fiber to both ends, as well as to 1X3, where the LSC IO chassis will be.

 

  2939   Mon May 17 10:57:16 2010 steveConfigurationSUSdamping restored to ETMYs

ETMY-south sus damping was restored

  2938   Mon May 17 02:10:10 2010 KojiConfigurationIOOHow to lock / align the MC

Let me remind you how to lock and align the IMC

To lock

1. Open the doors for the IMC/OMC chambers. Open the manual shutter of the PSL just in front of the optical window

2. Run scripts/MC/mcloopson

3. Set the MC length path gain 0.3 / Set the MC total gain "+20"

4. If you want to avoid excitation of the mirrors by air turbulence, put a big plastic film and put three posters on the top and both the sides on the floor to block the wind go into the chamber.

To shut down

1. Run scripts/MC/mcloopsoff

2. Close the manual shutter, Remove the wind blockers, and the light door of the chambers

To align the MC

1. Tweak MC2 and MC3 to get maximum transmittion and/or minimum reflection.

  2937   Sun May 16 19:25:45 2010 KojiUpdateGreen Lockingreflected beam at PD

Don't make a short cut. The beam size at a single place does not tell you anything.
Measure the mode of of the beam at multiple points. Calculate the mode matching ratio.

Align the mirrors precisely. Try to see the DC fringe. Predict the size of the DC fringe.

Test the demodulation system with a function generator. Find the 200kHz signal using the spectrum analyzer to find the signal and the optimal alignment.

Put the DC signal and the AC signal to the oscilloscope as X&Y.

Good luck.

 

  2936   Sun May 16 12:51:08 2010 kiwamuUpdateGreen Lockingreflected beam at PD

Mode matching to the cavity has been done.

Now the reflection from the cavity is successfully going into the PD.

However I could not see any obvious error signal.

I should compute and re-check the expected signal level.

 


(mode matching of the crystal)

On the last Wednesday, Kevin and I measured the mode profile before the PPKTP crystal,  and we found the Gaussian beam at the crystal is focused too tightly (w = 38 um).

In order to achieve the best conversion efficiency the waist size should be 50.0 um. So we moved a lens, which was located before the crystal, to 7 cm more away from the crystal. Eventually we obtained a better focus (w = 50.1 um).

Thanks, Kevin. You did a good job.

 

(mode matching of the cavity)

I put a lens with f=-50 mm after the crystal to diverge the green beam more quickly. Then the beam is going through the Faraday of 532 nm, two final modematching lenses and ETMY at last.

By shifting the positions of these lenses, I obtained the reflection from ITMY with almost the same spot size as that of the incident. This means modemathing is good enough.

I put two more steering mirrors before its injection to the ETM, this allows us to align the beam axis against the cavity.

I aligned the axis by using the steering mirrors and now the green beam are successfully hitting the center of both the ETM and the ITM.

Then the alignment of the ETM and the ITM was adjusted from medm, so that both reflection goes in the same path as that of the incident.

And then I put a PD (Thorlabs PDA36A) to see the reflection rejected by the Faraday.

Connecting a mixer and a local oscillator (Stanford func. generator) with f=200kHz, but I couldn't see any obvious PDH signal....

Since the PD is DC coupled, the signal is almost dominated by DC voltage. Even if I inserted a high pass filter to cut off the DC, the AC signal looks very tiny..

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