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ID Dateup Author Type Category Subject
  3278   Fri Jul 23 15:54:38 2010 kiwamuUpdateSUSPRM and TT installed

[ Jenne, Koji and Kiwamu]

 We have installed the PRM and the tip-tilt (TT) in the BS chamber.

We have started the in-vac work which takes about a week.

Today's mission was dedicated to installing the PRM and two TTs, one for the PRC and the other for the SRC, on the BS table in the chamber.

The work has been smoothly performed and we succeeded in installation of the PRM and a TT for the PRC.

But unfortunately the other TT got broken during its transportation from Bob's clean room.

 


 (what we did)

 (1) opened the light door of the BS chamber.

 (2) moved the BS tower to the right position according to Koji's layout drawing.

    - Prior to this work we screwed down the earthquake stops so that the mirror is fixed to the tower. Also we disabled the watchdog.

    - When moving it we used an allen key as a lever with an screw as a fulcrum. This idea was suggested by Jenne and it really worked well.

     The reason why we used this technique is that if we slide the tower by hands the tower can't go smoothly and it may sometimes skips.

     After that we checked the postion from some reference screw holes by using a caliper and we made sure that it was on the right position.

 (3) removed all of the square-shaped mirrors.

    - After this removal the mirrors were wrapped by aluminum foils and put in a usual clear box.

 (4) removed some optics because they had made the chamber space crowded.

    - These were also wrapped by aluminum foils and put in the box. Later we will put them back to the BS table.

 (5) brought the PRM tower from the Bob's clean room  and put it on the BS table.

   - The position of the PRM were coarsely aligned since we still don't have any 1064 beam going through the PRM.

 (6) brought two TTs also from Bob's clean room and put one of the TTs on the table.  

   - The position of the installed TT was coarsely adjusted. 

   - After we brought them we removed the aluminum foils covering the TTs and we found the wire of a TT got broken.

     It may have been damaged during its transportation from Bob's room because it was fine before the transportation.

 (7) closed the door

 

(the next things to do)

  * Installation of the OSEMs to the PRM

  * Installation of the pick off mirror and its associated optics

  * Arrangement of  the pzt mirror

 

Attachment 1: DSC_2275.JPG
DSC_2275.JPG
  3279   Fri Jul 23 16:00:35 2010 steveUpdateSAFETYcrane load test tomorrow

All 3 cranes will be load tested at 1 ton tomorrow morning between 9am and 2pm

Do not come to the 40m lab during this period. We may disturb your experiment.

Please prepare your touchy set ups to take this test.

  3280   Fri Jul 23 16:02:16 2010 RanaUpdatePSLReference Cavity Insulation

This is the trend so far with the copper foil wrapping. According to Megan's calculation, we need ~1 mm of foil and the thickness of each layer is 0.002" (1/20th of a mm), so we need ~20 layers. We have ~5 layers so far.

As you can see the out-of-loop temperature sensor (RCTEMP) is much better than before. We need another week to tell how well the frequency is doing -

the recent spate of power cycles / reboots of the PSL have interrupted the trend smoothness so far.

Attachment 1: Untitled.png
Untitled.png
  3281   Fri Jul 23 18:55:25 2010 kiwamuUpdateSUSPRM and TT installed

I updated the last entry.

  3282   Fri Jul 23 21:14:29 2010 RanaUpdatePSLReference Cavity Insulation

I wrapped another ~3 layers onto there. It occurs to me now that we could just get some 2mm thick copper plates made to fit over the stainless steel can.

They don't have to completely cover it, just mostly. I also took the copper circles that Steve had made and marked them with the correct beam height

and put them on Steve's desk. We need a 1" dia. hole cut into these on Monday.

To compensate for the cooling during my work, I've set the heater for max heating for 1 hour and then to engage the temperature servo.

I also noticed the HEPA VARIAC on the PSL was set to 100. Please set it back to 20 after completing your PSL work so that it doesn't disturb the RC temperature..

  3283   Fri Jul 23 21:35:48 2010 ranaUpdateCDSRerouted RFM around c1lsc, took RFM card out of c1lsc

 I just realized that an unfortunate casualty of this LSC work was the deletion of the slow controls for the LSC which we still use (some sort of AUX processor). For example, the modulation

depth slider for the MC is now in an unknown state.

  3284   Sat Jul 24 13:13:41 2010 rana, steve, albertoUpdateGeneralInitial Crane Inspection reveals flaws: wiring and oil

The guy from KroneCrane (sp?) came today and started the crane inspection on the X End Crane. There were issues with our crane so he's going to resume on Monday. We turned off the MOPA fur the duration of the inspection.

  1. None of our cranes have oil in the gearbox and it seems that they never did since they have never been maintained. Sloppy installation job. The crane oiling guy is going to come in on Monday.
  2. They tried to test the X-End crane with 2500 lbs. (its a 1 ton crane). This tripped the thermal overload on the crane as intended with this test. Unfortunately, the thermal overload switch disabled the 'goes down' circuit instead of the 'goes up' circuit as it should. We double checked the wiring diagram to confirm our hypothesis. Seems the X-End crane was wired up incorrectly in the first place 16 years ago. We'll have to get this fixed.

The plan is that they will bring enough weight to test it at slightly over the rating (1 Ton + 10 %) and we'll retry the certification after the oiling on Monday.

  3285   Sat Jul 24 14:03:19 2010 AlbertoUpdateElectronicsFSS Oscilaltor Phase Noise Measurement

[Rana, Alberto]

Today we measured the phase noise of the oscillator used for the FSS.

The source is a Wenzel crystal at about 21.5MHz that Peter Kalmus built some time ago.

We basically used the same technique that Frank and Megan have been using lately to measure the Marconi's phase noise.

Today we just did a quick measurement but today next week we are going to repeat it more carefully.

Attached is a plot that shows the measurement calibrated for a UGF at about 60 Hz. The noise is compared to that specified by Wenzel for their crystal.

The noise is bigger than that of the MArconi alone locked to the Rubidium standard (see elog entry). We don't know the reason for sure yet.

We'll get back to this problem next week.

Attachment 1: FSScrystalPhaseNoiseHigherGain.pdf
FSScrystalPhaseNoiseHigherGain.pdf
  3286   Sat Jul 24 14:27:36 2010 ranaUpdateElectronicsFSS Oscilaltor Phase Noise Measurement

I reconnected the RF signal to the FSS and to the FSS' EOM so that we could lock the refcav again.

I then started a 3 sec. period trianglewave on the AOM drive amplitude to see if there is a direct coupling from RIN to Frequency. Ideally we will be able to measure this by looking at the RCTRANS and the FSS-FAST.

  3287   Sun Jul 25 18:47:23 2010 AlbertoUpdateSVNOptickle 40mUpgrade model updated to include short cavity length corrections

I uploaded an updated optickle model of the upgrade to the SVN directory with the optickle models (here).

  3288   Mon Jul 26 08:51:31 2010 steveUpdatePEM lowering AC setpoint by 2F makes PSL happy

Quote:

The control room temp is warmer than usual. The heat exchanger Office Pro 18 set point was lowered from 70 to 68F yesterday.

The MOPA headtemp is higher also. The Neslab chiller bath temp peaks around 21.6 C daily. This should be rock solid 20.00 C

It did not have any effect.

Now, I have just lowered the thermostat setting of room 101 from 73 to71F  I  hope Koji can take this.

 Little change in the AC set temp can make wonders. Neslab chiller bath temp 19.99C is back to normal and daily variation of PSL are much better.

Attachment 1: htempRTemp.jpg
htempRTemp.jpg
  3289   Mon Jul 26 10:02:42 2010 josephbUpdateCDSRerouted RFM around c1lsc, took RFM card out of c1lsc

If you're refering to just the medm screen,  those can be restored from the SVN.  As we're moving to a new directory structure, starting with /opt/rtcds/caltech/c1/, the old LSC screens can all be put back in the /cvs/cds/caltech/medm/c1/lsc directory if desired.

The slow lsc aux crate, c1iscaux2, is still working, and those channels are still available.  I confirmed that one was still updating. As a quick test, I went to the SVN and pulled out the C1LSC_RFADJUST.adl file, renamed it to C1LSC_RFadjust.adl and placed it in /cvs/cds/caltech/medm/c1/lsc/, and checked it linked properly from the C1IOO_ModeCleaner.adl file.  I haven't touched the modulation depths, as I didn't want to mess with the mode cleaner, but if I get an OK, we can test that today and confirm that modulation depth control is still working.

Quote:

 I just realized that an unfortunate casualty of this LSC work was the deletion of the slow controls for the LSC which we still use (some sort of AUX processor). For example, the modulation

depth slider for the MC is now in an unknown state.

 

  3290   Mon Jul 26 10:04:24 2010 steveUpdateGeneralInitial Crane Inspection reveals flaws: wiring, oil and imbalance

Quote:

The guy from KroneCrane (sp?) came today and started the crane inspection on the X End Crane. There were issues with our crane so he's going to resume on Monday. We turned off the MOPA fur the duration of the inspection.

  1. None of our cranes have oil in the gearbox and it seems that they never did since they have never been maintained. Sloppy installation job. The crane oiling guy is going to come in on Monday.
  2. They tried to test the X-End crane with 2500 lbs. (its a 1 ton crane). This tripped the thermal overload on the crane as intended with this test. Unfortunately, the thermal overload switch disabled the 'goes down' circuit instead of the 'goes up' circuit as it should. We double checked the wiring diagram to confirm our hypothesis. Seems the X-End crane was wired up incorrectly in the first place 16 years ago. We'll have to get this fixed.

The plan is that they will bring enough weight to test it at slightly over the rating (1 Ton + 10 %) and we'll retry the certification after the oiling on Monday.

 The south end crane has one more flaw. The wall cantilever is imbalanced: meaning it wants to rotate south ward, because its axis is off.

This effects the rope winding on the drum as it is shown on Atm2

Atm1 is showing Jay Swar of KoneCrane and the two 1250 lbs load that was used for the test. Overloading the crane at 125% is general practice at load testing.

It was good to see that the load brakes were working well at 2500 lbs. Finally we found a good service company! and thanks for Rana and Alberto

for coming in on Saturday.

Attachment 1: 2500.JPG
2500.JPG
Attachment 2: sedrum.JPG
sedrum.JPG
  3291   Mon Jul 26 11:15:23 2010 GopalHowToCOMSOL TipsPictures from Transfer Function Tutorial on the Wiki

The attached pictures give a brief overview of my transfer function measurement procedure in COMSOL. For more details, please see the Wiki.

Screen_shot_2010-07-23_at_2.57.14_PM.png

Screen_shot_2010-07-23_at_2.57.38_PM.png

Screen_shot_2010-07-23_at_2.57.45_PM.png

Screen_shot_2010-07-23_at_2.58.05_PM.png

Screen_shot_2010-07-23_at_2.58.18_PM.png

Screen_shot_2010-07-23_at_2.59.02_PM.png

Screen_shot_2010-07-23_at_3.00.37_PM.png

  3292   Mon Jul 26 12:31:36 2010 kiwamuUpdateCDSfront end machine for the X end

A brief report about the new front end machine "C1ISCEX" installed on the X end (old Y end).

Still the DAC is not working.

 

- Timing card

It's working correctly.

The 1PPS clock signal is supplied by the vertex clock distributer via a 40m long fiber.

 

- ADC

All 16 channels are working well.

We can see the signals in the medm screen while injecting some signals to the ADC by using a function generator.

 

-DAC

All 16 channels do NOT work.

We can not see any signals at the DAC SCSI cable while digitally injecting a signal on the medm screen.

  3293   Mon Jul 26 14:24:46 2010 josephb, kiwamuUpdateCDSRFM test take 1

Kiwamu and I strung a temporary RFM fiber from the c1iscex machine (in the new 1X9 rack) to the c1sus machine (in the new 1X4 rack).  This was connected into the respective RFM cards.  Once we put the fiber in correctly, the status lights came on the RFM card, which is a good sign.  This did not go through the RFM bypass, and did not interfere with any other RFM connections.

We created a simple model to test the RFM card, which basically was 4 RFM memory locations passing back and forth between 2 filters on each machine.  These models were called c1rf0 (on c1sus) and c1rf1 (on c1iscex).  We added 4 entries to the /cvs/cds/caltech/chans/ipc/C1.ipc file corresponding to the 4 RFM memory locations, set their ipcType=RFM and set the ipcRate to 65536.  The ipcNum were set from 0 to 3. The models ran, however, the data we were trying to pass over the RFM card did not seem to be being passed.  Currently trying to contact Alex via e-mail to get debugging advice, and confirm the ipc file is setup correctly.

  3294   Mon Jul 26 20:12:18 2010 kiwamuUpdateSUSOSEMs on PRM

 [Alberto and Kiwamu]

We installed the OSEMs to the new PRM.

As I wrote down on the elog (see here)  today's mission was to install the OSEMs to the PRM.

After putting them on the tower we adjusted the readout offsets by sliding the OSEMs so that they can stay in the linear sensing ranges. 

Now all of the OSEMs have almost good separation distances from the PRM.

In the attached picture you can see the OSEMs installed on the PRM tower ( middle: PRM tower, left: BS tower)


(what we did)

 1. moved the PRM tower close to the door so that we could easily access the PRM.

 2. leveled the table by putting some weights and confirmed the level by a  bubble level tool.

     - We must level the table every time when we set / adjust any OSEMs,  otherwise the readout voltages of  the OSEMs vary every time due to the tilted table.

 3. released the PRM by loosing the earthquake stops

 4. put the OSEMs with approximately right separation distances from the PRM.

      -  At this phase we can see the readout of the OSEMs, which were oscillating freely because we still didn't enable the damping.

        -  The OSEM positions were checked by looking at useful notes on the wiki (see here).

 5. turned on the damping servo of the OSEMs

       - Without changing any gains, it worked well. 

      - Then we could see stable readouts of the OSEMs which didn't show any oscillations in turn because of the damping.

 6. checked the level of the table again

 7. set each of the OSEM readouts to the half of its maximum value by sliding their positions slightly.

      - The readout offsets were at almost the half value within +/- 100 mV accuracy (this was the best accuracy we could adjust by our hands)

 8. screwed down the earthquake stops to lock the PRM.

      - Now the damping is off.

 9. closed the door

 


(to be done)

 *  Putting the PRM tower back to the designed place

 *  Installation of the pick off mirror

 *  Arrangement of the PZT mirror

Attachment 1: DSC_2279.JPG
DSC_2279.JPG
  3295   Mon Jul 26 20:30:35 2010 JenneUpdateSUS2 Tip Tilts suspended and balanced

[Koji, Jenne]

We were on Team Cleanroom, while Kiwamu and Alberto were on Team Chamber.  Team Cleanroom suspended and balanced 2 Tip Tilts this afternoon.

One of the TTs that was suspended today is the one which was broken on Friday (see elog 3278).  We resuspended it using the regular 0.0036" diameter wire (91um).  We balanced it using the HeNe oplev, and then set it aside.  This TT has serial number 2.

We noticed that, like the previous 2 TT suspensions (this one before it was broken, and the one actually installed in the BS chamber on Friday, which is #3), there seems to be a little bit of hysteresis in the pointing.  The difference comes if we poke the top of the mirror holder and observe the place the reflected beam spot comes to rest at, and if we poke the bottom of the mirror holder.  The beam spot stays a little higher when we poke the top vs. when we poke the bottom. 

To combat this, we tried suspending our second TT of the day (the one that Kyung Ha and I had half finished) using thinner wire for the mirror holder.  We used the 0.0017" diameter wire (43um) that is used for the SOSes.  Unfortunately, it still seems like there is a similar hysteresis.  The thin-wire TT has serial number 4.

While working on TT4, we recalled that we have to include rubber dampers for the vertical blade springs.  Oooops!  We used some of the leftover #4-40 screws with viton tips that Zach and Mott had made for Earthquake stops to damp the vertical resonance of the blades.  We measured the Q factor by flicking the blades up or down.  We changed the oplev setup to be a shadow sensor setup, and watched the ringdown of the vertical mode on the 'scope.  We counted #cycles/time = frequency, and the t(1/2) time for the exponential ringdown to calculate the Q.  For the shadow sensor, we positioned the QPD in line with the initial HeNe beam, and placed the edge of the mirror holder clamp partially in the beam, so the beam was partly occluded.  When the mirror shook up and down, more or less of the beam was blocked, and we could see this power fluctuation on the 'scope.

Using the formula Q = pi  f0 T1/2 / ln(2) = 4.53 f0 T1/2, where T1/2 is the the time it takes for the amplitude to decay by half, we measured a Q of 31 for the vertical mode with no damping, and a Q of 14 with damping.  Koji confirmed the calculation and put it into wiki.

We need to go through the other TTs that have been assembled and give them their rubber dampers.

 

  3296   Tue Jul 27 11:24:53 2010 josephbHowToComputer Scripts / Programskilldataviewer script

I placed a script for killing all instances of the dataviewer program on the current computer in /cvs/cds/caltech/scripts/general/.  Its called killdataviewer.  This is intended to get rid of a bunch of zombie dataviewer processes quickly.  These processes get into this bad state when the dataviewer program is closed in any way other than the graphical menu File -> Exit option.

Its contents are very simple:

#/bin/bash

kill `ps -ef | grep dataviewer | grep -v grep | grep -v killdataviewer | awk '{print $2}'`

  3297   Tue Jul 27 11:43:24 2010 steveUpdatePEMair quality is bad today

The lab is at 30,000 and Pasadena air is at 1.1 e+6 particles /cf min of 0.5 micron.

Attachment 1: pemtoday.jpg
pemtoday.jpg
  3298   Tue Jul 27 12:02:31 2010 GopalUpdateOptic StacksPreliminary Transfer Function Measurements on MC1/MC3

I have successfully completed a preliminary transfer function measurement test on the MC1/MC3 stack in COMSOL. Using the measurement scheme described on the Wiki, I initialized a 1 N/m^2 sinusoidal perturbation on the bottom of the stack and measured the maximum displacement of the top layer. This preliminary test just calculated the responses to 1-,2-,3-,4-, and 5-Hz drives along the x-axis (pictures attached).

Currently, I am rerunning the same test but from 1-10 Hz with 0.1-Hz steps. When both x- and y-axis responses have been plotted, I can move on to repeating this entire process on the MC2 stack.

Attachment 1: MC1_MC3_FDA_1.png
MC1_MC3_FDA_1.png
Attachment 2: MC1_MC3_FDA_2.png
MC1_MC3_FDA_2.png
Attachment 3: MC1_MC3_FDA_3.png
MC1_MC3_FDA_3.png
Attachment 4: MC1_MC3_FDA_4.png
MC1_MC3_FDA_4.png
Attachment 5: MC1_MC3_FDA_5.png
MC1_MC3_FDA_5.png
  3299   Tue Jul 27 16:03:36 2010 ranaSummaryDAQDAQ timing test

Quote:

Since we now have a good measurement of the phase noise of the Rb clock Marconi locked to the Rb clock, I wanted to use that to check out the old DAQ system:

I used Megan's phase noise setup - Marconi #2 is putting out 11000013 Hz at 13 dBm into the ZP-3MH mixer. Marconi #1 is putting out 3 dBm at 11000000 Hz into the RF input.

The output goes through a 50 Ohm load and then a Mini-Circuits BNC LP filter (either 2 or 5 MHz). Then an SR560 set for low noise, G = 5, AC coupling, 1-pole LP @ 1 kHz.

This SR560 output goes into the channel C1:IOO-MC_DRUM1 (which is sampled at 16384 Hz with ICS-110B after the usual Sander Liu AA chassis containing the INA134s).

 This is the 0.3 mHz BW spectrum of this test - as you can see the apparent linewidth (assuming the width is all caused by the DAQ jitter) is comparable to the BW and therefore not resolved.

Basically, the Hanning window function is not sharp enough to do this test and so I will do it offline in Matlab.

Attachment 1: Untitled.png
Untitled.png
  3300   Tue Jul 27 16:33:50 2010 KojiSummaryGeneralHigh school students tour

Jenne made the 40m tour for the annual visit of 30-40 students.

c.f.

Tour 2009 http://nodus.ligo.caltech.edu:8080/40m/1717

Tour 2008 http://nodus.ligo.caltech.edu:8080/40m/737

 

Attachment 1: IMG_2657.jpg
IMG_2657.jpg
  3301   Tue Jul 27 18:42:57 2010 GopalUpdateOptic StacksBode Magnitude Plot and Concerns

I completed the frequency domain analysis mentioned previously in the x-direction. Although I ran it from 1-10 Hz, with 0.1-Hz increments, COMSOL was unable to complete the task past 7 Hz because the relative error was beyond the relative tolerance. To solve this issue, I'd have to rerun the simulation with a finer mesh, an unfavorable option because of the already-extensive run times. The Bode magnitude plot from this simulation is attached:

Bode_Mag_MC1_MC3.png

 

This simulation raises some questions about the feasibility of this method:

 

1) Do we have the computing power necessary?

 

I already moved my work from my personal Mac Pro to Kallo (4 GB --> 12 GB RAM difference). Now, instead of crashing the program constantly, I typically wait a half hour for a standard run of the model. Preferably, I could move my work to Megatron or some other workhorse-computer... but I also know that many of the big boys are already being strained as is.

 

2) Is it possible to take measurements through Matlab?

 

This way, I could write a script to instruct COMSOL and just run a few tests at a time overnight. Also, I wouldn't have to sit and record measurements manually as I've done here. The benefits of such an improvement warrant further attention. I'll work on this option next.

 

3) Up until what frequency do we need to model?

 

As I've shown, normal meshing yields data up to 7 Hz. Is this enough? Do we need more data? Certainly not less, I'm quite sure. We need to keep in mind that as frequency range increases, run times increase exponentially.

 

4) How do we incorporate gravity into the equation?

 

Gravity will produce a bit of extra force in the non-restoring direction for off-axis deviations, slightly decreasing the expected frequency. Whether or not this is an important effect is questionable, since the deviations are typically on the order of a micron, which is orders of magnitude smaller than the initial displacement I'm using on the base. I've decided to ignore this complication for now.

 

 

  3302   Tue Jul 27 21:38:21 2010 kiwamuUpdateSUSinstallation of in-vac optics

[Alberto and Kiwamu] 

We put the PRM back approximately on the right place.

Also we installed the pick off mirrors and the PZT mirror.

Since the main beam after the MMT still has not been well aligned , we put those optics approximately on the right place. A fine alignment of those will be performed later

The offsets of the PRM OSEMs are still kind of okay.

The next things we have to do are

(1) installation of a tip-tilt for the SRC, (2) alignement of those optics by using the main laser and (3) installation of the green optics.

 


what we did

 1. put the PRM back to the designed place.

     - After this, we released the PRM from the earthquake stops and turned on the damping servo.

      - Now the earthquake stops are at a distance of approximately 1mm from the PRM. These separation distances were tuned by counting the turn number when we screwed them off.

 2. leveled the table

 3. adjusted the separation distances from the PRM to the OSEMs.

    - The table below summarize the current OSEM offsets. LL may still need to be adjusted.

  Max./2 [V]

measured offsets [V] 

after adjustment 

discrepancy [%]
UL 0.874 0.928 + 6.2 %
UR 0.848 0.777 - 8.4 %
LL 1.038 0.796 - 23 %
LR 0.967 0.845 -12 %
SD 0.840 0.745 - 11%

 4. put the PZT mirror on the right place.

      -  This PZT mirror is going to be used for beam steering after the MMT.

 5. put the pick off mirror and its associated optics.

     -  This pick off mirror provides with the beam eventually going to IP_ANG and IP_POS.

 


current status

The table below shows the current status of the installed optics.

Red letters represent the incomplete states which still need further adjustment.

Blue letters represent the complete status which don't need any further adjustment.

 

name on the drawing

(see the wiki ) 

status
BS tower BS well aligned by a caliper
PRM tower PRM approximately aligned. LL OSEM
TIp-TIlt PR3 approximately aligned
Pick off Window (wedged) IPPO

wedge is correctly set (fat part is on the left).

 approximately aligned

steering mirror IPPOSSM1 mirror is correctly flipped. approximately aligned
steering mirror IPANGSM1 mirror is correctly flipped. approximately aligned
steering mirror IPANGSM2 approximately aligned
pzt mirror SM2 approximately aligned

 

Attachment 1: DSC_2284.JPG
DSC_2284.JPG
Attachment 2: DSC_2291.JPG
DSC_2291.JPG
  3303   Tue Jul 27 23:46:45 2010 JenneUpdateSUSQ measurements of 2 TTs

[Koji, Jenne]

We took measurements of the Q of all the modes that we could think of for TT#4, and then repeated several of the same measurements for TT#2.  We noticed that when we took off the backplane and then replaced it on TT#4, the pitch pointing had changed, so we had to repeat the balancing procedure by slightly shifting the position of the wire clamps relative to the mirror holder. No fun. We decided to quit removing the backplanes. 

The main conclusion of this evening's measurements of TT#4 is that everything looks very close to the design ideas.  Good work team!

TT#4:

'Free Swinging' values (just for interest)

Vert, no damping:   Q = 31.4

Pitch, no damping (ECD backplane removed): Q = ~700

Yaw, no ECDs: Q = ~900

Pos, no ECDs (no measurement) - we had already put the backplane back on, and didn't want to take it off again.

 

Damped Values:

Vert, with damping: Q = 14.3

Pitch, with ECDs: overdamped, so Q < 1/2

Yaw, with ECDs: Q = 2.3

Pos, with ECDs: Q = 1.4

Side, with ECDs: Q = 1.9

 

We also measured the resonant frequency of each of the ECDs for this TT (since we had the backplane removed anyway...)

ECD UL: 10.05Hz

ECD UR: 10.15Hz

ECD LL: 10.21Hz

ECD LR: 10.21Hz

 

TT#2:

Yaw, with ECDs: Q = 7.0

Pitch, with ECDs: overdamped, so Q < 1/2

Vert: Problematic.  No damping, f = 25.9Hz, Q = 36.  With rubber dampers, f = 20.0Hz, Q = 42.   Yes, you read that right.  The frequency is lower, and the Q is higher *with* the damping.  Perhaps our brains are fried.  Perhaps we've discovered new, inconsistent physics (awfully unlikely....). We'll revisit this again tomorrow to figure out what mistake we're making.

  3304   Wed Jul 28 01:05:44 2010 ranaUpdateSEIBode Magnitude Plot and Concerns

1) Gravity has to be included because the inverted pendulum effect changes the resonant frequencies. The deflection from gravity is tiny but the change in the dynamics is not. The results are not accurate without it. The z-direction probably is unaffected by gravity, but the tilt modes really feel it.

2) You should try a better meshing. Right now COMSOL is calculating a lot of strain/stress in the steel plates. For our purposes, we can imagine that the steel is infinitely stiff. There are options in COMSOL to change the meshing density in the different materials - as we can see from your previous plots, all the action is in the rubber.

3) I don't think the mesh density directly limits the upper measurement frequency. When you redo the swept-sine using the matlab scripting, use a logarithmic frequency grid like we usually do for the Bode plots. The measurement axis should go from 0.1 - 30 Hz and have ~100 points.

In any case, the whole thing looks promising: we've got real solid models and we're on the merge of being able to duplicate numerically the Dugolini-Vass-Weinstein measurements.

  3305   Wed Jul 28 12:09:06 2010 Sharmila,KatharineUpdateWIKI-40M UpdateMaglev

We have modeled our maglev setup in simulink but we have a few corrections to make since the system goes into undamped oscillations for an impulse in the input.

We have made a stable mount for the system and started to work on the 2X2 system using this mount. We have to figure out a way to match the magnets with the gain. We have attached the simulink block.

Picture_1.png

  3306   Wed Jul 28 12:16:03 2010 GopalUpdateSEIBode Magnitude Plot and Concerns

Quote:

1) Gravity has to be included because the inverted pendulum effect changes the resonant frequencies. The deflection from gravity is tiny but the change in the dynamics is not. The results are not accurate without it. The z-direction probably is unaffected by gravity, but the tilt modes really feel it.

2) You should try a better meshing. Right now COMSOL is calculating a lot of strain/stress in the steel plates. For our purposes, we can imagine that the steel is infinitely stiff. There are options in COMSOL to change the meshing density in the different materials - as we can see from your previous plots, all the action is in the rubber.

3) I don't think the mesh density directly limits the upper measurement frequency. When you redo the swept-sine using the matlab scripting, use a logarithmic frequency grid like we usually do for the Bode plots. The measurement axis should go from 0.1 - 30 Hz and have ~100 points.

In any case, the whole thing looks promising: we've got real solid models and we're on the merge of being able to duplicate numerically the Dugolini-Vass-Weinstein measurements.

I made some progress on a couple issues:

1) I figured out how to create log-transfer function plots directly in COMSOL, which eliminates the hassle of toggling between programs.

2) Instead of plotting maximum displacement, which could lead to inconsistencies, I've started using point displacement, standardizing to the center of the top surface.

3) I discovered that the displacement can be measured as a field vector, so the minor couplings between each translational direction (due to the asymmetry in the original designs) can be easily ignored. 

Bode_Disp_MC1_MC3_y.png

  3307   Wed Jul 28 12:31:00 2010 GopalUpdateWIKI-40M Update7.21.10-7.28.10 Weekly Update

Summary of this week's activities:

7/21: Frequency Domain Analysis of rectangular bar; discussed with Koji how to convert complex eigenfrequencies into phase factors.

7/23: Created Wiki page about FDA; Journal Club

7/26: Recreated Stack_1234.mph due to boundary value issues; FDA for 1,2,3,4,5 Hz

7/27: Discovered MC2 logbooks for later design; ran the complete x-translational FDA for Stack_1234.mph

7/28: Finished y-translational FDA (posted previously); "Tapered Cantilever" COMSOL tutorial for gravity-load analysis.

  3308   Wed Jul 28 12:53:32 2010 channaUpdateComputersnds data listener

For the sake of writing it down: /cvs/cds/caltech/apps/linux64/rockNDS

  3309   Wed Jul 28 13:06:47 2010 RazibUpdatePhase Camera 

Attached are some calculation that I did previously for the phasecamera setup. This shows the nature of the beat signal that we are measuring.

I am also trying to characterize the noise source of the camera also. Following images shows the mean dark noise (with no light on the camera) and the standard deviation for 100 snaps at an exposure time of 500 µs.

mean_100_snaps.pngstd_100_snaps.png

My target now is to measure the response gain of each pixel and how they vary over intensity. I already have a simplified setup on the table and will work on it today. Details will follow at the end of the day.

Attachment 3: phase_cam_calc.pdf
phase_cam_calc.pdf phase_cam_calc.pdf phase_cam_calc.pdf
  3310   Wed Jul 28 14:34:29 2010 channaUpdateComputersinstallation on allegra

I have done the following on allegra and rosalba:

[root@allegra caltech]# yum install glade2

On rosalba the matplotlib was out of date with respect to allegra.  I have no idea how the version 0.98 on allegra got there, but I left it.  However I updated rosalba to the epel version

  1 yum remove python-numpy
  2 yum install python-matplotlib numpy scipy --enablerepo=epel --disablerepo=rpmforge

 

This is all to support the LIGO data listener which now has a shortcut on rosalba and allegra's desktop.  It seems to work for (live mode) right now.
 

 

  3311   Wed Jul 28 14:54:56 2010 steveUpdateSAFETYevacuation drill at the 40m

Head count at the evacuation drill today. I checked  alarms and flashers  at room 104,102,101, 103, 105 and 107. They were really loud and bright. 

Attachment 1: P1060520.JPG
P1060520.JPG
  3312   Wed Jul 28 16:42:21 2010 steveUpdateGeneralCrane gear box cheched

Quote:

Quote:

The guy from KroneCrane (sp?) came today and started the crane inspection on the X End Crane. There were issues with our crane so he's going to resume on Monday. We turned off the MOPA fur the duration of the inspection.

  1. None of our cranes have oil in the gearbox and it seems that they never did since they have never been maintained. Sloppy installation job. The crane oiling guy is going to come in on Monday.
  2. They tried to test the X-End crane with 2500 lbs. (its a 1 ton crane). This tripped the thermal overload on the crane as intended with this test. Unfortunately, the thermal overload switch disabled the 'goes down' circuit instead of the 'goes up' circuit as it should. We double checked the wiring diagram to confirm our hypothesis. Seems the X-End crane was wired up incorrectly in the first place 16 years ago. We'll have to get this fixed.

The plan is that they will bring enough weight to test it at slightly over the rating (1 Ton + 10 %) and we'll retry the certification after the oiling on Monday.

 The south end crane has one more flaw. The wall cantilever is imbalanced: meaning it wants to rotate south ward, because its axis is off.

This effects the rope winding on the drum as it is shown on Atm2

Atm1 is showing Jay Swar of KoneCrane and the two 1250 lbs load that was used for the test. Overloading the crane at 125% is general practice at load testing.

It was good to see that the load brakes were working well at 2500 lbs. Finally we found a good service company! and thanks for Rana and Alberto

for coming in on Saturday.

 Jeff Stinson, technician of KoneCrane inspected the south end crane hoist gear box. This was the one that was really low on oil. The full condition require

~ 950cc of EPX-7 (50-70W) high viscosity gear oil. The remaining 120 cc oil was drained and the gear box cover was removed. See Atm 1

He found the gear box, load brake and gearing in good condition. The slow periodic sound of the drive was explained by the split bearings at Atm 3

The Vertex and the east end crane gear boxes needed only 60 cc oil to be added to each Atm 4 and their drives were tested.

Conclusion: all 3 gear boxes and drives are in good working condition.

Tomorrow's plan: load test at 1 ton and correct-check  3 phase wiring.

Attachment 1: P1060503.JPG
P1060503.JPG
Attachment 2: P1060511.JPG
P1060511.JPG
Attachment 3: P1060515.JPG
P1060515.JPG
Attachment 4: P1060517.JPG
P1060517.JPG
  3313   Wed Jul 28 17:32:37 2010 kiwamuUpdateSUSinstallation of in-vac optics

[Jenne, Koji and Kiwamu]

We have installed two steering mirrors and the green periscope.

Also we took the tip-tilt out from the chamber for characterization.


1. installed two steering mirrors

     - We installed IPPOSSM2 and IPPOSSM3.

    - Because IPPOSSM2 is a new 0 deg mirror so we newly engraved "Y1-LW1-2037-1064-0-AR" on the mount and deleted  the previous enegravement.

      For the 0 deg mirror itself, it had already been engraved by Koji. The wedge was horizontally aligned.

      Now IPPOSSM2 is off from the right place by 5 inch for convenience because it may touch our stomachs when we try to lean further into the chamber.

    - IPPOSSM3 is a 45 deg mirror which used to be in the chamber and had been already correctly engraved, so we didn't have to newly engrave on it. Now it's on the right place approximately.

 2. put three oplev mirrors

      - Two of them are approximately on the place, but one which is going to be on the center of the table is not on the place because there is a cable distributer sitting exactly there.

 3. installed the green periscope

      - Both the mirrors and the periscope were correctly engraved.

     - Now it's sitting on the right place approximately.

 4. removed the tip-tilt 

      -  This tip-tilt is now in the clean room and the mechanical mode will be characterized. 

 


 The next things to be done

* Cross-coupling evaluation of the PRM OSEMs

* Rearrangement of the cable distributer panel.

   - In order to do this we have to pull its cables which are attached to the stack.

* Installation of three green steering mirrors

   - All of them need to be engraved.

* Installation of two tip-tilt

  - One for the SRC and the other for the PRC

  3314   Wed Jul 28 18:24:57 2010 JenneUpdateGreen Locking2 Green Periscopes have mirrors, aligned

[Koji, Jenne, Kiwamu]

This is to describe the work that went on in the Cleanroom today.  Kiwamu's entry will detail the tidbits that happened in the chamber.

We engraved the periscope mounts with the mirror info for the mirrors which were placed in the periscope.  We also engraved the barrels of the optics with their info, for posterity.  Koji carefully put the mirrors into the periscopes.  Since we have wedged optics, the goal was to have the front HR surface of the mirror parallel to the plane of the mount, and leave a bit of space behind one side of the optic (if we just pushed the optic fully in, the HR surface wouldn't be flat, and would send the beam off to the left or right somewhere).  Once the mirrors were mounted in the periscopes, we checked the vertical levelness of the outcoming beam.  For the first periscope (the one which has been installed on the BS table), the beam was deflected upward (2.5)/32 inches over 55inches.  This corresponds to a 1.4mRad vertical deflection.  The second periscope (which will eventually be installed on the OMC table) had a deflection of 1/32 over 55inches, or 0.6mRad.  We did not check the side-to-side deflection for either of the periscopes.

We also engraved one more DLC mount with mirror info, and put a mirror into the mount.  This is one of the optics that was placed onto the BS table today, which Kiwamu will describe.

We removed TT#3 from the BS chamber so that it could have rubber vertical dampers installed, and be characterized.  For future reference, the #'s of the Tip Tilts refers to the serial number of the suspension block piece, which forms the top horizontal bar of the frame. 

  3315   Thu Jul 29 10:39:43 2010 kiwamuUpdateSUSRe: installation of in-vac optics

I updated the last entry about the in-vac work (see here)

  3316   Thu Jul 29 11:33:38 2010 kiwamuUpdateCDSPCI5565 driver for RFM

 Yesterday I installed a PCI-5565 driver on new C1SUS in order to test the RFM.

Since the RFM on the new CDS is not working, we had to test it by using some softwares.

I installed a driver for PCI-5565 on C1SUS and ran a test script wich is one of the packaged test scripts in the driver.

So far the RFM card on C1SUS looked correctly mounted, but I didn't check the memory location and the sending/ receiving functions.

This test will continue sometime on August because right now the RFM test is not higher priority.

 


Some notes:

Driver package

      Alex suggested to use a driver package for PIC-5565 called "RFM2g Linux 32/64-bit PCIE/PCI/PMC driver for x86 kernels R7.03" , which is available on  this web site.

And the package contains some useful test scripts which exactly we want to run for RFM test.

 

Installation and test script

      I downloaded the driver and put it on C1SUS.  

After doing usual "unzip", "tar" and "make" things, I ran one of the test script called "rfm2g_util".

Currently it lives under /home/controls/Desktop/162-RFM2G-DRV-LNX-R07_03-000/rfm2g/diags/rfm2g_util on C1SUS.

It invokes an interactive shell and firstly it asks the mount point of the RFM card.

I eventually found the card was mounted on #1 which means the card is correctly mounted.

 

Some detail procedures will be summarized on the wiki later.

  3317   Thu Jul 29 12:13:28 2010 kiwamuSummaryCDSnear term plan

 [Joe and Kiwamu]

current_setup_v2.png

  3318   Thu Jul 29 12:31:09 2010 KojiSummaryGeneralLab Schedule

July
29 Thu BS chamber work: Move cable towers / green steering mirrors / (2 TTs with TT charactrization) / Put the heavy door by 5PM.
30 Fri Pumping down
31 Sat WFS work by Nancy

Aug
1 Sun - 5 Thu WFS work by Nancy
5 Thu PSL Table prep
6 Fri PSL Table prep / Likely to shut down the PSL

9 Mon PSL Table prep / shutting down of the PSL (optional)
10 Tue PSL box Frame lifting
12 Thu PSL table tapping

16 Mon - 17 Tue concrete pouring preparation
19 Thu - 23 Fri Tripod placement
24 Tue - 26 Thu concrete pouring

Attachment 1: PSL_work_schedule.pdf
PSL_work_schedule.pdf
  3319   Thu Jul 29 12:31:24 2010 josephbUpdateCDSWorking DAC, working IOP - next up SUS

Ok, after a few minutes of talking to Alex, I got the correct "GUI syntax" through my head, and we now have a simple working green end control which in fact puts signals out through the DAC.

Note to self, do not put any additional filters or controls in the IOP module.  Basically just change the master block with GDS numbers, DCU_ID numbers, etc.  When using a control model, copy the approriate ADC and ADC selector or DAC to the control model.  It will magically be connected to the IOP.

A correct example of a simple control model is attached.

Next in line is to get the adapter boxes for SUS into the new 1X5 rack and get started on SUS filter conversion and figuring out which ADC/DAC channels correspond to which inputs.

 

Attachment 1: Simple_Green_Control.png
Simple_Green_Control.png
  3321   Thu Jul 29 15:35:21 2010 josephb, kiwamuUpdateCDSWorking out ADC/DAC/BO wiring

We are currently using the SUS wiring diagram found on Ben Abbott's page (link here) to determine the ADC/DAC/BO channel numbers for each individual optics inputs and outputs.  Basically it involves tracking the paths back from the Pentek's, XY220, and IC110Bs to a point where we can identify it as a Coil UL or a PD whitening filter control or whatever it might be.

Once done we will have a nice wiki page describing what the final wiring is going to be, along with which ADC effectively plugs into which analog board and so forth.

  3322   Thu Jul 29 17:11:16 2010 GopalUpdateCOMSOL TipsIncluding Gravity in COMSOL

[Gopal, Jan]

For the past couple of days, Jan and I have been discussing a major issue in COMSOL involving modeling both oscillatory and non-oscillatory forces simultaneously while using FDA. It turns out that he and I had run into the same problem at different times and with different projects. After discussing with an expert, Jan had decided in the past that this simple task was impossible via direct means.

The issue could still be resolved if there was a way for us to work on the Weak Form of the differential equations describing the system:

  • Usually, one must define weight as a body load in the negative-z direction. However, this problematically instantiates a new force in COMSOL, which is automatically driven over the range of frequencies during FDA.
  • Instead, we could define gravity as an anti-restoring force, since we assume that the base of the stack is fixed.
  • In other words, Fg = (ρ*g/L)*x + (ρ*g/L)*y for a point mass which is constrained on the bottom (for small angles).
  • Working in Weak Form then, we'd never have to define an explicit gravity load-- this could just be an extra couple of terms in the differential equation which are related entirely to the x- and y-vectors (well-defined for each mesh point). This would fool COMSOL into never tacking on the oscillatory term during FDA. 

According to current documentation however, Weak Form analysis is not yet possible in COMSOL 4.0. Jan suggested moving my work over to ANSYS or waiting for the 4.0 upgrade, but there's probably not enough time left in my SURF for either of these options. I suggested attempting a backwards-compatibility test to COMSOL 3.5; Jan and I will be exploring this option some time next week. 

  3323   Thu Jul 29 17:12:48 2010 josephb, kiwamuUpdateCDSRe:Working out ADC/DAC/BO wiring

We have installed  4 BO boards, 3 DAC boards and 1 ADC board for new C1SUS.

They are on the 1Y5 rack. 

 

 DSC_2302.png

  3324   Thu Jul 29 20:43:32 2010 GopalSummaryOptic StacksModeling Tips and Tilts

I have discovered a method of completely characterizing the 6x6 response of all six types (x-,y-, and z- translational/rotational) of oscillatory disturbances at the base of the stack.

  • "Tipping" drives are trivial, and simply require a face load in the appropriate direction.
  • "Tilting" drives could use a torque, but I am instead implementing multiple edge loads in opposing directions to create the appropriate net curl. This curl will be kept constant across the three axes for sake of comparing the resulting transfer functions.
  • "Tipping" responses are once again trivial, and merely require the displacement vector of the top center coordinate to be recorded.
  • "Tilting" responses require the normal vector to be recorded and manipulated to produce the angular coordinates (assuming right-handed coordinate system):
    • θx = tan-1(x/z)
    • θy = tan-1(y/z)
    • θz = tan-1(y/x)

The first three concepts have been confirmed through simulations to produce correct transfer functions. The last test seems to be producing some problems, in that the vector normal to the equilibrium position (an obvious and useless piece of information) is sometimes given instead of the vector normal to the position of maximum displacement. This means that, as of now, I have the capability of measure the half of the complete 6x6 matrix of transfer functions in the coming weeks. The first three of eighteen transfer functions are attached below and will be included in my progress report.

XTrans_XDisp.pngYTrans_XDisp.pngZTrans_XDisp.png

  3325   Thu Jul 29 21:13:39 2010 DmassUpdateGreen Lockingwaist positon of Gaussian beam in PPKTP crystals

Quote:

The mode profile of Gaussian beams in our PPKTP crystals was calculated.

I confirmed that the Rayleigh range of the incoming beam (1064 nm) and that of the outgoing beam (532 nm) is the same.

And it turned out that the waist postion for the incoming beam and the outgoing beam should be different by 13.4 mm toward the direction of propagation.

These facts will help us making optical layouts precisely for our green locking.


(detail)

The result is shown in the attached figure, which is essentially the same as the previous one (see the entry).

The horizontal axis is the length of the propagation direction, the vertical axis is the waist size of Gaussian beams.

Here I put x=0 as the entering surface of the crystal, and x=30 mm as the other surface.

The red and green solid curve represent the incoming beam and the outgoing beam respectively. They are supposed to  propagate in free space.

And the dashed curve represents the beams inside the crystal.

A trick in this calculation is that: we can assume that  the waist size of 532 nm is equal to that of 1064 nm divided by sqrt(2) . 

If you want to know about this treatment in detail,  you can find some descriptions in this paper;

"Third-harmonic generation by use of focused Gaussian beams in an optical super lattice" J.Opt.Soc.Am.B 20,360 (2003)"

If I understand your elog, you are just calculating the the offset in position space that you get by having a refractive index.

Did you end up changing the mode matching so that the rayleigh range (which changes with refractive index) was confocally focused inside the crystal (e.g. Zr = 15 mm?

 

  3326   Thu Jul 29 22:08:32 2010 AlbertoUpdateSUSMore optics installed on the BS table

[Koji, Steve, Kiwamu, Alberto]

- This afternoon we installed a few new optics on the BS table: GR_PBS, GRY_SM2, GRY_SM1.

- We pulled up the cables so that we had more freedom to move one of the cable towers farther South.

- Then we re-leveled the table. PRM OSEMs were adjusted to be nominal insertions.

- Koji released the earthquake stops on BS but the readout of the OSEMs was apparently frozen on the MEDM screens.
Initially we thought it was a software problem. a nuclear reboot didn't solve it. We spent the following three hours investigating the cause.
Eventually it turned out that the earthquake stops on BS weren't actually fully released.

We opened the tank and accessed to BS. Releasing the earthquake stops in full solved the issue. The OSEMs readout went back to normal.

  3327   Thu Jul 29 22:58:25 2010 kiwamuUpdateGreen Lockingwaist positon of Gaussian beam in PPKTP crystals

- As you said, I just calculated the waist position in the crystal because the speed of light changes in a medium and eventually the waist position also changes.

- Yes, I did. Once you get a beam with the right waist size, you just put your crystal at the waist position with the offset.

  In fact you don't have to think about the rayleigh range inside of the crystal because what we care is the waist size and it doesn't change.

Quote:

 If I understand your elog, you are just calculating the the offset in position space that you get by having a refractive index.

Did you end up changing the mode matching so that the rayleigh range (which changes with refractive index) was confocally focused inside the crystal (e.g. Zr = 15 mm?

  3328   Fri Jul 30 00:02:15 2010 DmassUpdateGreen Lockingwaist positon of Gaussian beam in PPKTP crystals

Quote:

- As you said, I just calculated the waist position in the crystal because the speed of light changes in a medium and eventually the waist position also changes.

- Yes, I did. Once you get a beam with the right waist size, you just put your crystal at the waist position with the offset.

  In fact you don't have to think about the rayleigh range inside of the crystal because what we care is the waist size and it doesn't change.

Quote:

 If I understand your elog, you are just calculating the the offset in position space that you get by having a refractive index.

Did you end up changing the mode matching so that the rayleigh range (which changes with refractive index) was confocally focused inside the crystal (e.g. Zr = 15 mm?

 I thought we cared about satisfying the confocal focusing parameter, that is to say we want to set Zr = 2L_crystal. If Zr changes inside the crystal, this is the number we care about..isn't it NOT the waist size, but the rayleigh range we care about? I am not entirely sure what youre response is saying you did...

  1. Calculate Zr = pi * wo^2/(lamba/n)
  2. Do mode matching to get this wo in free space
  3. Calculate the offset you need to move the oven by using n
  4. Move hte ovens

OR

  1. Calculate Zr = pi*wo^2/(lamba)
  2. Do mode matching to get this in free space
  3. Calculate the offset you need to move your ovens using n
  4. Move your ovens

I guess the waist size would also let me know - are you using 69 um or 53 um waist size?

ELOG V3.1.3-