40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log, Page 36 of 344  Not logged in ELOG logo
ID Date Author Type Categorydown Subject
  5291   Tue Aug 23 17:45:22 2011 jamieUpdateSUSITMX, ITMY, ETMX clamped and moved to edge of tables

In preparation for tomorrow's drag wiping and door closing, I have clamped ITMX, ITMY, and ETMX with their earthquake stops and moved the suspension cages to the door-edge of their respective tables.  They will remain clamped through drag wiping.

ETMY was left free-swinging, so we will clamp and move it directly prior to drag wiping tomorrow morning.

  5293   Tue Aug 23 18:25:56 2011 jamieUpdateSUSSRM diagnalization OK

By looking at a longer data stretch for the SRM (6 hours instead of just one), we were able to get enough extra resolution to make fits to the very close POS and SIDE peaks.  This allowed us to do the matrix inversion.  The result is that SRM looks pretty good, and agrees with what was measured previously:

SRM SRM.png        pit     yaw     pos     side    butt
UL    0.869   0.975   1.140  -0.253   1.085  
UR    1.028  -1.025   1.083  -0.128  -1.063  
LR   -0.972  -0.993   0.860  -0.080   0.834  
LL   -1.131   1.007   0.917  -0.205  -1.018  
SD    0.106   0.064   3.188   1.000  -0.011 
4.24889

 

  5294   Wed Aug 24 09:11:19 2011 jamieUpdateSUSETMY SUS update: looks good. WE'RE READY TO CLOSE

We ran one more free swing test on ETMY last night, after the last bit of tweaking on the SIDE OSEM.  It now looks pretty good:

ETMY ETMY.png       pit     yaw     pos     side    butt
UL   -0.323   1.274   1.459  -0.019   0.932 
UR    1.013  -0.726   1.410  -0.050  -1.099 
LR   -0.664  -1.353   0.541  -0.036   0.750 
LL   -2.000   0.647   0.590  -0.004  -1.219 
SD    0.021  -0.035   1.174   1.000   0.137 
4.23371

 So I declare: WE'RE NOW READY TO CLOSE UP.

  5295   Wed Aug 24 11:30:27 2011 jamie, jenne, kiwamu, suresh, steveUpdateSUSETMX wiped, replaced, door on

We've closed up ETMX:

  • the optic was drag wiped
  • the suspension tower was put back in place
  • earthquake stops were backed off the appropriate number of turns, and de-ionized
  • chamber door was put on
  5296   Wed Aug 24 11:40:21 2011 jamie, jenne, kiwamu, suresh, steveUpdateSUSproblem with ITMX

ITMX was drag wiped, and the suspension was put back into place.  However, after removing all of the earthquake stops we found that the suspension was hanging in a very strange way.

The optic appears to heavily pitched forward in the suspension.  All of the rear face magnets are high in their OSEMs, while the SIDE OSEM appears fine.  When first inspected, some of the magnets appeared to be stuck to their top OSEM plates, which was definitely causing it to pitch forward severely.  After gently touching the top of the optic I could get the magnets to sit in a more reasonable position in the OSEMs.  However, they still seem to be sitting a little high.  All of the PDMon values are also too low:

  nominal now
UL 1.045 0.767
UR 0.855 0.718
LR

0.745

0.420

LL

0.780

0.415
SD

0.840

0.752

Taking a free swing measurement now.

  5297   Wed Aug 24 12:08:56 2011 jamieUpdateSUSITMX, ETMX, ETMY free swinging

ITMX: 998245556

ETMX, ETMY: 998248032

  5298   Wed Aug 24 16:13:36 2011 kiwamuUpdateSUSbroke UL magnet on ITMX

I broke the UL magnet on ITMX

The ITMX tower was shipped into the Bob's clean room to put the magnet back on.

 

 Since we found that all the magnets were relatively high (#5296) in the shadow sensors, we decided to slide the OSEM holder bar upward.

During the work, I haven't made the OSEMs far enough from the magnets.

So the magnets and OSEMs touched as I moved the holder.

Then the UL magnets were broken off and fell into the UL coil.

 

  5299   Wed Aug 24 17:05:11 2011 JenneUpdateSUSBroken UL magnet on ITMX

Quote:

The ITMX tower was shipped into the Bob's clean room to put the magnet back on. 

 Repair work is delayed.  I need the "pickle pickers" that hold the magnet+dumbbell in the gluing fixture, for gluing them to the optic.  Here at the 40m we have a full set of SOS gluing supplies, except for pickle pickers.  We had borrowed Betsy's from Hanford for about a year, but a few months ago I returned all of the supplies we had borrowed.  Betsy said she would find them in her lab, and overnight them to us.  Since the problem occurred so late in the day, they won't get shipped until tomorrow (Thursday), and won't arrive until Friday.

I also can't find our magnet-to-dumbbell gluing fixture, so I asked her to send us her one of those, as well. 

I have 2 options for fixing ITMX.  I'll write down the pros and cons for each, and we can make a decision over the next ~36 hours.

OPTIONS:

(#1) Remove dumbbell from optic.  Reglue magnet to dumbbell. Reglue magnet+dumbbell to optic.

(#2) Carefully clean dumbbell and magnet, without breaking dumbbell off of optic.  Glue magnet to dumbbell.

PROS:

(#1) Guarantee that magnet and dumbbell are axially aligned.

(#2) Takes only 1 day of glue curing time.

CONS:

(#1) Takes 2 days of glue curing time. (one for magnet to dumbbell, one for set to optic.)

(#2) Could have slight mismatch in axis of dumbbell and magnet.  Could accidentally drop a bit of acetone onto dumbbell-to-optic glue, which forces us into option 1, since this might destroy the integrity of the glue joint (this would take only the 2 days already required for option 1, it wouldn't force us to take 2+1=3 days).

  5300   Thu Aug 25 08:12:09 2011 steveUpdateSUSETMY & ITMY wiped, replaced, vac door on

Quote:

We've closed up ETMX:

  • the optic was drag wiped
  • the suspension tower was put back in place
  • earthquake stops were backed off the appropriate number of turns, and de-ionized
  • chamber door was put on

 jamie, jenne, kiwamu, suresh, steve

 

ETMY and ITMY were treated the same way as ETMX. The BS chamber was closed with heavy vac door yesterday also. The IOO access connector's inner jamnuts are torqued to 45 ft/lbs as all vac door bolts.

The vac envelope is ready for pumpdown condition, except ITMX chamber with light atm door cover.

Jenne will summeries the condition of dust on the  TMs before and after the drag wipes.

  5301   Thu Aug 25 13:10:42 2011 JenneUpdateSUSDrag wiping

As we have seen in the past, both of the ITMs were more dusty than the ETMs, presumably because we have the vertex open much more often than the ends.  Kiwamu and I wiped all of the optics until we could no longer see any dust particles within a ~1.5 inch diameter area around the center. 

Since we have ITMX out for magnet gluing, I'll probably drag wipe both front and back surfaces before putting it back in the suspension cage.  All of the optics have clear dust on the AR surfaces, but we can't get to that surface while the optics are suspended.  For the ETMs this isn't too big of a deal, but it does concern me a bit for the ITMs and other transmissive optics we have.  I don't think it's bad enough yet though to warrant removing optics from suspensions just to wipe them.

  5302   Thu Aug 25 15:20:03 2011 JenneUpdateSUSBroken UL magnet on ITMX

Dmass just reminded me that the usual procedure is to bake the optics after the last gluing, before putting them into the chambers.  Does anyone have opinions on this? 

On the one hand, it's probably safer to do a vacuum bake, just to be sure.  On the other hand, even if we could use one of the ovens immediately, it's a 48 hour bake, plus cool down time.  But they're working on aLIGO cables, and might not have an oven for us for a while.  Thoughts?

  5305   Thu Aug 25 17:57:35 2011 SureshUpdateSUSBroken UL magnet on ITMX

Quote:

Dmass just reminded me that the usual procedure is to bake the optics after the last gluing, before putting them into the chambers.  Does anyone have opinions on this? 

On the one hand, it's probably safer to do a vacuum bake, just to be sure.  On the other hand, even if we could use one of the ovens immediately, it's a 48 hour bake, plus cool down time.  But they're working on aLIGO cables, and might not have an oven for us for a while.  Thoughts?

I think we should follow the established procedure in full, even though it will cost us a few more days.  I dont think we should consider the vacuum bake as something "optional".  If the glue has any volatile components they could be deposited on the optic resulting in a change in the coating and consequently optical loss in the arm cavity.

 

 

  5306   Fri Aug 26 07:53:59 2011 steveUpdateSUSBroken UL magnet on ITMX

Quote:

Dmass just reminded me that the usual procedure is to bake the optics after the last gluing, before putting them into the chambers.  Does anyone have opinions on this? 

On the one hand, it's probably safer to do a vacuum bake, just to be sure.  On the other hand, even if we could use one of the ovens immediately, it's a 48 hour bake, plus cool down time.  But they're working on aLIGO cables, and might not have an oven for us for a while.  Thoughts?

 Follow full procedure for full strength, minimum risk

  5308   Fri Aug 26 15:30:36 2011 JenneUpdateSUSITMX magnet reglued
The ITMX UL magnet has been reglued.

I *very carefully* using the corner of a cleaned razor blade dropped single drops of acetone onto the top of the dumbbell, and scratched off the residual glue. I didn't want to get even a sprinkle of acetone on the dumbbell-glass junction, and I managed to avoid it. Also, the dumbbell never broke off of the glass (something I've never been able to achieve before), so all I had to do was glue the magnet back onto the dumbbell.

I also scratched the glue from the magnet, after soaking in acetone. I made sure to keep track of which way the magnet had been glued by putting it in the pickle picker that I received from Betsy before getting rid of the glue. I specifically did not compare the polarity of this magnet to the others still glued, because I have seen that in the past break magnets from dumbbells. They can't really handle sideways forces. But since it's glued the same way that it was, it should be fine.

I then aligned the optic in the gluing fixture. I test-fit the pickle picker with magnet, to ensure that the axes of the dumbbell and magnet were aligned as closely as possible. I adjusted the optic to make this axial alignment as perfect as I could see with my eye. Unfortunately the fixture doesn't allow a whole lot of viewing angles of the magnet-dumbbell joint, so we'll see how well I did after I remove it from the fixture.

I put a little dab of epoxy on the end of the magnet, spread it around so it coated the whole surface, and glued it on.

I'll come in tomorrow (Saturday) to check on it, and take it out of the fixture. If it's going to break coming out of the fixture, which I hope won't happen, but has happened before, then I want to be able to fix it again asap.
  5311   Sat Aug 27 14:33:04 2011 JenneUpdateSUSITMX magnet status

As I feared, since I couldn't see the magnet-to-dumbbell joint from all angles, they ended up being off by ~1/3 of a magnet diameter. 

Because I don't want to deal with finding another failed glue joint tomorrow, I removed the magnet and dumbbell from the optic, and broke the manget off of the dumbbell.  As with yesterday, I kept track of which end of the magnet had been glued to the dumbbell. 

I got a new dumbbell, removed all the glue from the magnet, and reglued them together, in the fixture that ensures they are well aligned. 

Tomorrow I will come in and glue the magnet dumbbell assembly to the ITM.

  5314   Sun Aug 28 20:15:11 2011 JenneUpdateSUSITMX magnet status

Quote:

Tomorrow I will come in and glue the magnet dumbbell assembly to the ITM.

 Glued.

Tomorrow afternoon I'll remove the optic from the fixture, and put it in the oven.

  5318   Mon Aug 29 16:27:34 2011 ManuelConfigurationSUSSUS Summary Screen

I edited the C1SUS_SUMMARY.adl file and set the channels in alarm mode to show the values in green, yellow and red according to the values of the thresholds (LOLO, LOW, HIGH, HIHI)

I wrote a script in python, which call the command ezcawrite and ezcaread, to change the thresholds one by one.

You can call this program with a button named "Change Thresholds one by one" in the menu come down when you click the  button.

I'm going to write another program to change the thresholds all together.

  5320   Mon Aug 29 18:24:11 2011 jamieUpdateSUSITMY stuck to OSEMs?

ITMY, which is supposed to be fully free-swinging at the moment, is displaying the tell-tale signs of  being stuck to one of it's OSEMs.  This is indicated by the PDMon values, one of which is zero while the others are max:

UL: 0.000
UR: 1.529
LR: 1.675
LL: 1.949
SD: 0.137

Do we have a procedure for remotely getting it unstuck?  If not, we need to open up ITMYC and unstick it before we pump.

 

  5322   Tue Aug 30 10:49:29 2011 steveUpdateSUSBS & PRM damping restored

I have restored the damping of BS and PRM. Today is janitor day. He is shaking things around the lab.

  5326   Tue Aug 30 14:44:06 2011 kiwamuUpdateSUSITMY released without opening chambers

The ITMY mirror was released. The OSEM readouts became healthy.

 

To see what is going on, I changed the PIT DC bias slider on ITMY from 0.8 to -1 or so, and then the optic started showing a free swinging behavior.

If there were no responses to the DC bias, I was going to let people to open the chamber to look at it closer, but fortunately it released the optic.

Then I brought the slider back to 0.8, and it looked still free swinging. Possibly the optic had been stacked on some of the OSEMS as Jamie expected.

Quote from #5320

ITMY, which is supposed to be fully free-swinging at the moment, is displaying the tell-tale signs of  being stuck to one of it's OSEMs. 

Do we have a procedure for remotely getting it unstuck?  If not, we need to open up ITMYC and unstick it before we pump.

 

  5332   Thu Sep 1 15:07:45 2011 steveUpdateSUSwhy ITMY is moving more ?

Atm1, ITMY and the SRM are on the same isolation stack.  So why does  the SRM move twice as much?

Atm2, We should check the ITMY  SIDE_OSEM before pump down. Anatomically correct, beautiful picture taken by Kiwamu on August 22

Attachment 1: itmy_srm_etmx.jpg
itmy_srm_etmx.jpg
Attachment 2: P8220152.JPG
P8220152.JPG
  5333   Thu Sep 1 15:59:46 2011 steveUpdateSUSlight doors on at the ITMs

Suresh, Kiwamu and Steve

Heavy chamber doors replaced by light ones at  ITMX-west and ITMY-north locations.

  5337   Fri Sep 2 17:52:16 2011 kiwamuUpdateSUSITMX realigned

The new ITMX was aligned by changing the DC biases.

The resultant DC biases are reasonably small.

C1:SUS-ITMX_PIT_COMM = -0.2909

C1:SUS-ITMX_YAW_COMM = -0.0617

 

The alignment was done by trying to resonate the green light in the X arm cavity.

The spot position of the green light on the ITMX mirror looked good. This was confirmed by inserting a sensor card.

I did the OSEM mid-range adjustment and the rotation adjustment but at the end the OSEM DC voltage has changed due to the DC bias operation.

The OSEM rotation was approximately optimized so that all the face shadow sensors are sensitive to the POS motion but the SIDE shadow sensor is insensitive to the POS motion.

It needs a free swinging diagnosis.

  5338   Fri Sep 2 17:57:18 2011 kiwamuUpdateSUSRe: ITMY released without opening chambers

It stacked again . We should take a closer look at it.

Quote from #5326

The ITMY mirror was released. The OSEM readouts became healthy.

 

  5341   Tue Sep 6 08:05:53 2011 steveUpdateSUSITMX must be touching

Quote:

The new ITMX was aligned by changing the DC biases.

The resultant DC biases are reasonably small.

C1:SUS-ITMX_PIT_COMM = -0.2909

C1:SUS-ITMX_YAW_COMM = -0.0617

 

The alignment was done by trying to resonate the green light in the X arm cavity.

The spot position of the green light on the ITMX mirror looked good. This was confirmed by inserting a sensor card.

I did the OSEM mid-range adjustment and the rotation adjustment but at the end the OSEM DC voltage has changed due to the DC bias operation.

The OSEM rotation was approximately optimized so that all the face shadow sensors are sensitive to the POS motion but the SIDE shadow sensor is insensitive to the POS motion.

It needs a free swinging diagnosis.

 ITMX OSEMs   UL 1.8V,   UR 1.7V,   LR 0V,   LL 0V,   SD 1.3V  at the same bias setting shown above. May be a lose earth quake tip?or magnet is touching?

Attachment 1: osemITMX.jpg
osemITMX.jpg
  5342   Tue Sep 6 11:21:33 2011 JenneUpdateSUSITMX rehung (Friday)

[Jenne, Katrin, Jamie]

I'm a bad kid, and forgot to elog my Friday morning work...

Bob gave me back ITMX after a 48hour bake at 80C + clean RGA scan Friday morning after coffee and doughnuts.  Katrin helped me put it back in the suspension wire. 

While I was leveling the optic (making sure the scribe lines on each side of the optic are at the same height off the table), Katrin cut some new viton for replacement EQ stops.  The optic was missing one lower earthquake stop (the one that Jamie noticed last week), and somehow one other rubber piece came out of the EQ stop on another lower screw while we were re-suspending the optic.  We put the new stops in, and then checked the balance of the test mass.

The oplev is still the HeNe laser that is leveled to the level optical table in the cleanroom.  The lever arm is ~1.5 meters, and over that distance the reflected beam was pointed "up" in pitch by ~1.5mm, which is less than one beam diameter of the HeNe.  This is well within our ability to correct using the OSEMs.

We then locked the test mass, and installed it in the chamber.  I approximately did the half-voltage centering of the OSEMs, leaving the fine-tuning to Kiwamu for after lunch. 

  5345   Tue Sep 6 17:48:57 2011 kiwamuUpdateSUSfree swinging test on ITMY

Tue Sep  6 17:48:02 PDT 2011
999391697

  5346   Tue Sep 6 17:56:12 2011 JenneUpdateSUSfree swinging test on ITMX

Quote:

Tue Sep  6 17:48:02 PDT 2011
999391697

 Kiwamu excited ITMY (which Suresh had already started).  I just kicked ITMX:

Tue Sep  6 17:55:21 PDT 2011
999392136

  5349   Tue Sep 6 21:33:21 2011 JenneUpdateSUSDiagonalizability of ITMX and ITMY is acceptable

[Rana and Kiwamu on ITMX, Jenne and Suresh on ITMY, Zombie/brains meeting on accepting the matricies]

 

Optic Spectra Matrix "Badness"
ITMX ITMX.png       pit     yaw     pos     side    butt
UL    0.584   0.641   1.396  -0.578   0.558 
UR    0.755  -1.359   0.120  -0.286   0.262 
LR   -1.245  -0.139   0.604  -0.388   0.511 
LL   -1.416   1.861   1.880  -0.681  -2.669 
SD   -0.753   0.492   3.263   1.000  -1.523 
 5.85983
ITMY  ITMY.png           pit     yaw     pos     side    butt
UL    1.000   0.572   1.134  -0.059   0.951  
UR    0.578  -1.428   0.916  -0.032  -1.024  
LR   -1.422  -0.531   0.866  -0.009   1.086  
LL   -1.000   1.469   1.084  -0.036  -0.939  
SD   -0.662   0.822   1.498   1.000   0.265  
4.47727
 

 OSEMs were tweaked.  We have decided that both ITMs are okay in terms of their diagonalization.  ITMY isn't stellar when you look at the spectra, but it's kind of close enough.  Certainly the matrix looks fine.

Aside from checking on POX, I think we're now ready to close up.  Check back later tonight for a final decision announced on the elog.

  5352   Wed Sep 7 00:39:34 2011 ranaUpdateSUSITMX adjustments

(What we did)

* Moved SUS to edge of table for OSEM adjustment.

* Leveled the table in this temporary tower position.

* Rotated all OSEMs to give some seperation between magnets and LED/PD packages.

* Moved the upper OSEM bracket a little bit upward.

* All the OSEM holding set screws were short with flat heads; this is annoying since we would like to use them more like thumbscrews. Steve took the long set-screws out of the old ITMX cage and we swapped them. Need to order ~100 silver-plated socket head spare/replacements.

* Took pictures of OSEMs.

* Moved tower back to old position.

* Releveled the table (added one rectangular weight in the NW corner of the table).

* Find that ITMX OSEMs were a couple 100 micron out of position; we adjusted them in-situ in the final position of the tower, trying not to rotate them. All mean voltages now are within 100 mV of ideal half-light.

* Back/front EQ positions adjusted by the screw method. bottom/top stops adjusted earlier.

* OSEM cables tied down with copper wire.

* Increased the incident power up to 91 mW going into MC to temporarily make the POX beam more visible.

* The POX beam was checked. It was exiting from the chamber and going through about the center of the viewport.

  5353   Wed Sep 7 00:44:51 2011 JenneUpdateSUSFreeswing all

I just started a freeswing all, as a final check before we pump:


Wed Sep  7 00:43:21 PDT 2011
999416616

Wed Sep  7 00:43:32 PDT 2011
WATCHDOGS WILL BE RESET 5 HOURS AFTER THIS TIME
sleeping for 5 hours...

Jamie: Please do a quickie analysis (at least for the ITMs) before helping Steve with the heavy doors.

I closed the PSL shutter.

Both ITM chambers were checked for tools, so there should be nothing left to do but put the heavy doors on, and begin pumping.

  5355   Wed Sep 7 08:14:01 2011 steveUpdateSUSfinal OSEM check

All fine, except ITMX_sensor_UL's  60  counts deep hoop for an hour.

Attachment 1: finalcheck.jpg
finalcheck.jpg
Attachment 2: ITMX10min.jpg
ITMX10min.jpg
Attachment 3: finalsum.png
finalsum.png
  5356   Wed Sep 7 09:21:57 2011 jamieUpdateSUSSUS spectra before close up

Here are all suspension diagonalization spectra before close up. Notes:

  • TMX looks the worst, but I think we can live with it. The large glitch in the UL sensor at around 999423150 (#5355) is worrying. However, it seemed to recover. The spectra below were taken from data before the glitch.
  • ITMY has a lot of imaginary components. We previously found that this was due to a problem with one of it's whitening filters (#5288). I assume we're seeing the same issue here.
  • SRM needs a little more data to be able to distinguish the POS and SIDE peaks, but otherwise it looks ok.
ITMX ITMX.png        pit     yaw     pos     side    butt
UL    0.355   0.539   0.976  -0.500   0.182 
UR    0.833  -1.406  -0.307  -0.118   0.537 
LR   -1.167   0.055   0.717  -0.445   0.286 
LL   -1.645   2.000   2.000  -0.828  -2.995 
SD   -0.747   0.828   2.483   1.000  -1.637 
8.01148
ITMY  ITMY.png        pit     yaw     pos     side    butt
UL    1.003   0.577   1.142  -0.038   0.954  
UR    0.582  -1.423   0.931  -0.013  -1.031  
LR   -1.418  -0.545   0.858   0.008   1.081  
LL   -0.997   1.455   1.069  -0.017  -0.934  
SD   -0.638   0.797   1.246   1.000   0.264
 4.46659
BS  BS.png        pit     yaw     pos     side    butt
UL    1.612   0.656   0.406   0.277   1.031  
UR    0.176  -1.344   1.683  -0.058  -0.931  
LR   -1.824  -0.187   1.594  -0.086   0.951  
LL   -0.388   1.813   0.317   0.249  -1.087  
SD    0.740   0.301  -3.354   1.000   0.035 
 5.49597
PRM  PRM.png        pit     yaw     pos     side    butt
UL    0.546   1.436   1.862  -0.345   0.866  
UR    1.350  -0.564   0.551  -0.055  -0.878  
LR   -0.650  -0.977   0.138   0.023   0.858  
LL   -1.454   1.023   1.449  -0.268  -1.398  
SD    0.634  -0.620  -0.729   1.000   0.611
 5.78216
SRM      
ETMX ETMX.png        pit     yaw     pos     side    butt
UL    0.863   1.559   1.572   0.004   1.029  
UR    0.127  -0.441   1.869   0.480  -1.162  
LR   -1.873  -0.440   0.428   0.493   0.939  
LL   -1.137   1.560   0.131   0.017  -0.871  
SD    1.838   3.447  -0.864   1.000  -0.135 
 5.5259
ETMY  ETMY.png        pit     yaw     pos     side    butt
UL   -0.337   1.275   1.464  -0.024   0.929  
UR    1.014  -0.725   1.414  -0.055  -1.102  
LR   -0.649  -1.363   0.536  -0.039   0.750  
LL   -2.000   0.637   0.586  -0.007  -1.220  
SD    0.057  -0.016   1.202   1.000   0.142 
 4.22572
MC1  MC1.png        pit     yaw     pos     side    butt
UL    0.858   0.974   0.128   0.053  -0.000  
UR    0.184  -0.763   0.911   0.018   0.001  
LR   -1.816  -2.000   1.872   0.002   3.999  
LL   -1.142  -0.263   1.089   0.037   0.001  
SD    0.040   0.036  -0.216   1.000  -0.002 
 5.36332
MC2  MC2.png        pit     yaw     pos     side    butt
UL    1.047   0.764   1.028   0.124   0.948  
UR    0.644  -1.236   1.092  -0.088  -0.949  
LR   -1.356  -0.680   0.972  -0.096   1.007  
LL   -0.953   1.320   0.908   0.117  -1.095  
SD   -0.092  -0.145  -0.787   1.000  -0.065 
 4.029
MC3  MC3.png        pit     yaw     pos     side    butt
UL    1.599   0.343   1.148   0.168   1.101  
UR    0.031  -1.647   1.139   0.202  -1.010  
LR   -1.969   0.010   0.852   0.111   0.893  
LL   -0.401   2.000   0.861   0.077  -0.995  
SD   -0.414   0.392  -1.677   1.000   0.018 
3.61734

 

  5370   Fri Sep 9 14:55:03 2011 kiwamuUpdateSUSOSEM pictures on ITMs

The OSEM pictures taken in Sep/6 have been uploaded to Picasa.

https://picasaweb.google.com/foteee

  5375   Sat Sep 10 02:28:45 2011 kiwamuUpdateSUSfree swinging test in vacuum condition

All the optcs were excited

Sat Sep 10 02:14:11 PDT 2011
999681266

 

  5376   Sat Sep 10 11:07:37 2011 ranaHowToSUSOptical Lever Servo Tuning thoughts

Now that we are in a moderately stable condition, its time to design the optical lever feedback transfer functions. We should think carefully about how to do this optimally.

In the past, the feedback shape was velocity damping from 0-10 Hz, with some additional resonant gain around the pendulum and stack modes. There were some low pass filters above ~30 Hz. These were all hand tuned.

I propose that we should look into designing optimal feedback loops for the oplevs. In principle, we can do this by defining some optimal feedback cost function and then calculate the poles/zeros in matlab.

How to define the cost function (? please add more notes to this entry):

1) The ERROR signal should be reduced. We need to define a weight function for the ERROR signal: C_1(f) = W_1(f) * (ERR(f)^2)

2) The OL QPDs have a finite sensing noise, so there is no sense in suppressing the signal below this level. Need to determine what the sensing noise is.

3) The feedback signal at high frequencies (30 Hz < f < 300 Hz) should be low passed to prevent adding noise to the interferometer via the A2L coupling. It also doesn't help to reduce this below the level of the seismic noise. The cost function on the feedback should be weighted apprpriately given knowledge about the sensing noise of the OL, the seismic noise (including stack), and the interferometer noise (PRC, SRC, MICH, DARM).

4) The servo should be stable: even if there is a negligible effect on the ERROR signal, we would not want to have more than 10 dB of gain peaking around the UGFs.

5) The OL QPDs are dominated by drift of the stack, laser, etc. at some low frequencies. We should make sure the low frequency feedback is high passed appropriately.

6) Minimize transmitted power rms in single arm lock etc.

  5403   Wed Sep 14 07:51:20 2011 steveUpdateSUSPRM damping restored

The PRM damping was restored at side sensor var 1050

  5409   Wed Sep 14 20:30:36 2011 ranaUpdateSUSSome screens are still bad

I've found that a few of the screens still have Whited-Out fields due to naming changes (OL SUM and ALS-> TM OFFSET). I attach a screen shot of it.

The OL screens have the wrong SUM names and the IFO ALIGN screen is pointing to the wrong SUS screens.

Untitled.png

  5411   Wed Sep 14 22:07:41 2011 ranaUpdateSUSITM Oplevs are broken

I went to see what was wrong with the ITMs and found that people have been working on them and have left them in a broken state with no elog entry.

This is sad and unacceptable.

Whoever is working on these should post into the elog what the Oplev layout plan is, have someone check it, and ONLY THEN get to work on it.

The layout as it looks tonight is too complicated. With too many optics we will not have a low noise optical lever setup. The new layout should use a bare minimum number of optics and only use very stable mounts.

mm.jpg

  5415   Thu Sep 15 07:28:08 2011 steveUpdateSUSPRM damping restored

Quote:

The PRM damping was restored at side sensor var 1050

 The PRM sus damping restored.

  5417   Thu Sep 15 15:11:38 2011 kiwamuUpdateSUSf2a filters on BS and PRM

The f2a filters were newly designed and installed on BS and PRM.

So the lock of PRMI will be more stable .

Once the SRM oplev project settles down, I will adjust the f2a filters on SRM too.

Attachment 1: PRMf2a.png
PRMf2a.png
Attachment 2: BS_f2a.png
BS_f2a.png
  5418   Thu Sep 15 16:45:59 2011 PaulUpdateSUSITMY and SRM Oplev status

Today I worked on getting the ITMY and SRM oplevs back in working order. I aligned the SRM path back onto the QPD. I put excitations on the ITMY and SRM in pitch and yaw and observed the beam at the QPDs to check for clipping. They looked clean from clipping.

 
Measurements of the beam power at various points:
 
Straight after the laser - 7.54mW
After the BS in the SRM path - 1.59mW
After the BS in the ITMY path - 3.24mW
Incident on the SRM QPD - 0.03mW
Incident on the ITMY QPD - 0.25mW
 
Counts registered from the QPD sum channels:
 
SRM QPD SUM dark count - 1140
SRM QPD SUM bright count - 3250
 
ITMY QPD SUM dark count - 150
ITMY QDP SUM bright count - 12680
 
The power incident on the SRM QPD seems very low with respect to the ITMY QPD. Is the SRM mirror coating not very reflective for the He-Ne laser?There are some back reflections from lenses, which we should be careful of to avoid scattering.
  5419   Thu Sep 15 17:00:10 2011 Paul and SteveUpdateSUSNew ITMY and SRM oplev plan

 We have made a new plan for the ITMY and SRM oplev optical path which uses as few optics as possible. This should help to reduce coupling from vibrations of optics in the oplev path back into the GW channel. To get enough room for the turning mirror into the SRM it might be necessary to move the POY optics a bit nearer to the tank. 

Attachment 1: oplev_plan1.png
oplev_plan1.png
  5421   Thu Sep 15 18:12:21 2011 JenneUpdateSUSfree swinging test in vacuum condition

Quote:

All the optcs were excited

Sat Sep 10 02:14:11 PDT 2011
999681266

 

 

Optic The Plot Input Matrix BADness
ITMX  ITMX.png       pit     yaw     pos     side    butt
UL    0.601   0.680   1.260  -1.009   0.223 
UR    0.769  -1.254  -0.175  -0.179   0.581 
LR   -1.231   0.065   0.566  -0.480   0.252 
LL   -1.399   2.000   2.000  -1.310  -2.944 
SD   -0.580   0.868   2.451   1.000  -1.597 

 
7.95029
ITMY  ITMY.png       pit     yaw     pos     side    butt
UL    1.067   0.485   1.145  -0.195   0.929 
UR    0.548  -1.515   0.949  -0.142  -1.059 
LR   -1.452  -0.478   0.855  -0.101   1.051 
LL   -0.933   1.522   1.051  -0.153  -0.962 
SD   -0.530   0.903   2.115   1.000   0.142 
3.93939
ETMX ETMX.png       pit     yaw     pos     side    butt
UL    0.842   1.547   1.588  -0.018   1.026 
UR    0.126  -0.453   1.843   0.499  -1.173 
LR   -1.874  -0.428   0.412   0.511   0.934 
LL   -1.158   1.572   0.157  -0.006  -0.867 
SD    1.834   3.513  -0.763   1.000  -0.133
5.39825
ETMY ETMY.png       pit     yaw     pos     side    butt
UL   -0.344   1.280   1.425  -0.024   0.903 
UR    1.038  -0.720   1.484  -0.056  -1.161 
LR   -0.618  -1.445   0.575  -0.040   0.753 
LL   -2.000   0.555   0.516  -0.007  -1.184 
SD   -0.047  -0.038   0.986   1.000   0.083 
4.15747
BS  BS.png       pit     yaw     pos     side    butt
UL    1.549   0.655   0.393   0.263   0.997 
UR    0.192  -1.345   1.701  -0.063  -0.949 
LR   -1.808  -0.206   1.607  -0.085   0.952 
LL   -0.451   1.794   0.299   0.241  -1.101 
SD    0.724   0.293  -3.454   1.000   0.037 
5.66432
PRM  PRM.png       pit     yaw     pos     side    butt
UL    0.697   1.427   1.782  -0.337   0.934 
UR    1.294  -0.573   0.660  -0.068  -0.943 
LR   -0.706  -1.027   0.218   0.016   0.867 
LL   -1.303   0.973   1.340  -0.254  -1.257 
SD    0.369  -0.448  -0.496   1.000   0.456 
5.1026
SRM   Can't invert....need to fix the peak-finding.  
MC1  MC1.png       pit     yaw     pos     side    butt
UL    0.872   0.986   0.160   0.054   0.000 
UR    0.176  -0.752   0.917   0.018   0.000 
LR   -1.824  -2.000   1.840   0.002   3.999 
LL   -1.128  -0.262   1.083   0.038  -0.000 
SD    0.041   0.036  -0.193   1.000  -0.001 
5.31462
MC2  MC2.png       pit     yaw     pos     side    butt
UL    1.042   0.767   0.980   0.131   0.928 
UR    0.577  -1.233   1.076  -0.134  -0.905 
LR   -1.423  -0.640   1.020  -0.146   1.050 
LL   -0.958   1.360   0.924   0.120  -1.117 
SD   -0.073  -0.164  -0.702   1.000  -0.056 
4.07827
MC3  MC3.png       pit     yaw     pos     side    butt
UL    1.595   0.363   1.152   0.166   1.107 
UR    0.025  -1.629   1.135   0.197  -0.994 
LR   -1.975   0.008   0.848   0.105   0.904 
LL   -0.405   2.000   0.865   0.074  -0.995 
SD   -0.433   0.400  -1.624   1.000   0.022 
3.64881

 

  5422   Thu Sep 15 18:24:54 2011 PaulUpdateSUSITMY and SRM Oplev current status - comparison with ITMY

Just to find out where we are currently, I plotted the ITMY and SRM oplev spectra along with the ETMY oplev spectra. ETMY seems to be very good, so comparing with this seemed useful, so we know how much we have to improve by. The SRM power spectrum appears to be around 2 orders of magnitude higher than ETMY over pretty much the whole measurement band. The ITMY power spectrum is not so bad as the SRM above about 60Hz. Next thing to do is to check the dark noise level for the ITMY and SRM QPDs.

Attachment 1: oplev_spectra_comparison.pdf
oplev_spectra_comparison.pdf
  5423   Thu Sep 15 18:31:27 2011 PaulUpdateSUSITMY and SRM Oplev current status - comparison with ITMY

Quote:

Just to find out where we are currently, I plotted the ITMY and SRM oplev spectra along with the ETMY oplev spectra. ETMY seems to be very good, so comparing with this seemed useful, so we know how much we have to improve by. The SRM power spectrum appears to be around 2 orders of magnitude higher than ETMY over pretty much the whole measurement band. The ITMY power spectrum is not so bad as the SRM above about 60Hz. Next thing to do is to check the dark noise level for the ITMY and SRM QPDs.

 The title of this post should of course have been " ... - comparison with ETMY" not " ... - comparison with ITMY"

  5427   Thu Sep 15 22:26:32 2011 PaulUpdateSUSITMY Oplev QPD dark noise PSD

 I took a dark noise measurement for the ITMY QPD, for comparison with measurements of the oplev noise later on. Initially I was plotting the data from test points after multiplication by the oplev matrix (i.e. the OLPIT_IN1 / OLYAW_IN1), but found that the dark noise level seemed higher than the bright noise level (!?). Kiwamu realised that this is because at that test point the data is already divided by QPD SUM, thus making the dark noise level appear to be greater than the bright level, since QPD SUM is much smaller for the dark measurements. The way around this was to record the direct signals from each quadrant before the division. I took a power spectrum of the dark noise from each quadrant, then added them in quadrature, then divided by QPD SUM at the end to get an uncalibrated PSD. Next I will convert these into the equivalent for pitch and yaw noise spectra. To calibrate the plots in radians per root Hz requires some specific knowledge of the oplev path, so I won't do this until I have adjusted the path.

Attachment 1: ITM_dark_QPD_PSD.pdf
ITM_dark_QPD_PSD.pdf
  5428   Thu Sep 15 22:31:44 2011 ManuelUpdateSUSSummary screen

I changed some colors on the Summary of Suspension Sensor  using my italian creativity.

I wrote a script in Python to change the thresholds for the "alarm mode" of the screen.

The script takes a GPS-format start time as the 1st argument and a duration time as the second argument.

For every channel shown in the screen, it compute the mean value during this time.

The 3rd argument is the ratio between the mean and the LOW threshold. The 4th argument is the ratio between the mean and the LOLO threshold.

Then it sets the thresholds simmetrycally for HIGH and HIHI threshold.

It does that for all channels skipping the Gains and the Off Sets because this data are not stored.

For example is ratio are 0.9 and 0.7 and the mean is 10, thresholds will be LOLO=7, LOW=9, HIGH=11, HIHI=13.

You can run the script on pianosa writing on a terminal '/opt/rtcds/caltech/c1/scripts/SUS/set_thresholds.py' and the arguments.

I already run my program with those arguments: 1000123215 600 0.9 0.7

The time is of this morning at 5:00 for 10 minutes

 

This is the help I wrote

HELP: This program set the thresholds for the "alarm mode" of the C1SUS_SUMMARY.adl medm screen.

 Written by Manuel Marchio`, visiting student from University of Pisa - INFN for the 2011 summer at Ligo-Caltech. Thrusday, 15th September 2011.

The 1st argument is the time in gps format when you want to START the mean

The 2nd argument is the DURATION

The 3rd argument is the ratio of the LOW and the HIGH thresholds. It must be in the range [0,1]

The 4th argument is the ratio of the LOLO and the HIHI thresholds. It must be in the range [0,1]

Example: path/set_thresholds.py 1000123215 600 0.9 0.7

and if the the mean is 10, thresholds will be set as LOLO=7, LOW=9, HIGH=11, HIHI=13

 

Attachment 1: sussum.png
sussum.png
  5429   Fri Sep 16 00:08:30 2011 PaulUpdateSUSITMY Oplev QPD dark and bright noise spectra

 I tried again at plotting the ITMY_QPD noise spectra in for dark and bright operation. Before we had the strange situation where the dark noise seemed higher, but Kiwamu noticed this was caused by dividing by the SUM before the testpoint I was looking at. This time I tried just multiplying by the measured SUM for bright and dark to normalise the spectra against each other. The results looks more reasonable now, the dark noise is lower than the bright noise for a start! However, the dark noise spectrum now doesn't look the same as the one I showed in my previous post.

Attachment 1: ITMY_oplev_dark_noise_vs_bright_noise.pdf
ITMY_oplev_dark_noise_vs_bright_noise.pdf
  5432   Fri Sep 16 14:03:53 2011 PaulUpdateSUSSRM oplev QPD noise measurement

 I checked the dark and bright noise of the SRM oplev QPD. The SRM QPD has a rather high dark level for SUM of 478 counts. The dark noise for the SRM QPD looked a little high in the plot against the bright noise (see first attachment), so I plotted the dark noise with the ITMY QPD dark noise (see second attachment). It seems that the SRM QPD has a much higher dark noise level than the ITMY! In case anyone is wondering, to make these traces I record the data from the pitch and yaw test points, then multiply by the SUM (to correct for the fact that the test point signal has already been divided by SUM). I will check the individual quadrants of the SRM QPD to see if one in particular is very noisy. If so, we/I should probably fix it.

Attachment 1: SRM_oplev_dark_noise_vs_bright_noise.pdf
SRM_oplev_dark_noise_vs_bright_noise.pdf
Attachment 2: SRM_ITMY_QPD_dark_noise_comparison.pdf
SRM_ITMY_QPD_dark_noise_comparison.pdf
ELOG V3.1.3-