ID |
Date |
Author |
Type |
Category |
Subject |
5264
|
Thu Aug 18 15:54:35 2011 |
steve | Update | SUS | damped and undamped OSEMs |
damped sus at atm1 and freeswingging sus at atm2
|
Attachment 1: 5susLL.jpg
|
|
Attachment 2: 8freeSUSLL.jpg
|
|
5266
|
Fri Aug 19 01:15:22 2011 |
Suresh | Update | SUS | FreeSwing all optics |
I ran "freeswing all" at Fri Aug 19 01:09:28 PDT 2011 (997776583) and "opticshutdown" as well.
|
5269
|
Fri Aug 19 10:26:53 2011 |
steve | Update | SUS | OSEM sensor spectra |
Free swingging OSEM sensors LL at atm |
Attachment 1: 8freeSUSosemSensors.jpg
|
|
5282
|
Tue Aug 23 01:09:44 2011 |
kiwamu | Update | SUS | free swinging test |
excited all the optics ---
Tue Aug 23 01:08:00 PDT 2011
998122096 |
5286
|
Tue Aug 23 10:38:27 2011 |
jamie | Update | SUS | SUS update |
SUS update before closing up:
- MC1, MC2, ITMX look good
- MC3, PRM look ok
- SRM pos and side peaks are too close together to distinguish, so the matrix is not diagnalizable. I think with more data it should be ok, though.
- all ITMY elements have imaginary components
- ITMY, ETMX, ETMY appear to have modest that swapped position:
- ITMY: pit/yaw
- ETMX: yaw/side
- ETMY: pos/side
- MC3, ETMX, ETMY have some very large/small elements
Not particularly good. We're going to work on ETMY at least, since that one is clearly bad.
OPTIC |
|
M |
cond(B) |
MC1 |
 |
pit yaw pos side butt
UL 0.733 1.198 1.168 0.050 1.057
UR 1.165 -0.802 0.896 0.015 -0.925
LR -0.835 -1.278 0.832 -0.002 0.954
LL -1.267 0.722 1.104 0.032 -1.064
SD 0.115 0.153 -0.436 1.000 -0.044 |
4.02107 |
MC2 |
 |
pit yaw pos side butt
UL 1.051 0.765 1.027 0.128 0.952
UR 0.641 -1.235 1.089 -0.089 -0.942
LR -1.359 -0.677 0.973 -0.097 1.011
LL -0.949 1.323 0.911 0.121 -1.096
SD -0.091 -0.147 -0.792 1.000 -0.066 |
4.02254 |
MC3 |
 |
pit yaw pos side butt
UL 1.589 0.353 1.148 0.170 1.099
UR 0.039 -1.647 1.145 0.207 -1.010
LR -1.961 -0.000 0.852 0.113 0.896
LL -0.411 2.000 0.855 0.076 -0.994
SD -0.418 0.396 -1.624 1.000 0.019 |
3.60876 |
PRM |
 |
pit yaw pos side butt
UL 0.532 1.424 1.808 -0.334 0.839
UR 1.355 -0.576 0.546 -0.052 -0.890
LR -0.645 -0.979 0.192 0.015 0.881
LL -1.468 1.021 1.454 -0.267 -1.391
SD 0.679 -0.546 -0.674 1.000 0.590 |
5.54281 |
BS |
 |
pit yaw pos side butt
UL 1.596 0.666 0.416 0.277 1.037
UR 0.201 -1.334 1.679 -0.047 -0.934
LR -1.799 -0.203 1.584 -0.077 0.952
LL -0.404 1.797 0.321 0.247 -1.077
SD 0.711 0.301 -3.397 1.000 0.034 |
5.46234 |
SRM |
NA |
NA |
NA |
ITMX |
 |
pit yaw pos side butt
UL 0.458 1.025 1.060 -0.065 0.753
UR 0.849 -0.975 1.152 -0.199 -0.978
LR -1.151 -1.245 0.940 -0.243 1.217
LL -1.542 0.755 0.848 -0.109 -1.052
SD -0.501 -0.719 2.278 1.000 -0.153 |
4.4212 |
ITMY |
 |
pit yaw pos side butt
UL 0.164 1.320 1.218 -0.086 0.963
UR 1.748 -0.497 0.889 -0.034 -1.043
LR -0.252 -2.000 0.782 -0.005 1.066
LL -1.836 -0.183 1.111 -0.058 -0.929
SD -0.961 -0.194 1.385 1.000 0.239 |
4.33051 |
ETMX |
 |
pit yaw pos side butt
UL 0.623 1.552 1.596 -0.033 1.027
UR 0.194 -0.448 1.841 0.491 -1.170
LR -1.806 -0.478 0.404 0.520 0.943
LL -1.377 1.522 0.159 -0.005 -0.860
SD 1.425 3.638 -0.762 1.000 -0.132 |
4.89418 |
ETMY |
 |
pit yaw pos side butt
UL 0.856 0.007 1.799 0.241 1.005
UR -0.082 -1.914 -0.201 -0.352 -1.128
LR -2.000 0.079 -0.104 -0.162 0.748
LL -1.063 2.000 1.896 0.432 -1.119
SD -0.491 -1.546 2.926 1.000 0.169 |
9.11516 |
|
5287
|
Tue Aug 23 11:57:22 2011 |
kiwamu | Update | SUS | free swinging test during lunch time |
excited all the optics. (with ITMY WTF OFF)
Tue Aug 23 11:52:52 PDT 2011
998160788 |
5288
|
Tue Aug 23 14:49:14 2011 |
jamie, jenne, kiwamu, suresh, keiko | Update | SUS | Adjustment of ETMY, issue with ITMY whitening |
Before lunch we took a closer look at two of the suspensions that were most problematic: ITMY and ETMY. Over lunch we took new free swinging data. Results below:
- For ITMY we discovered that the whitening on the UL sensor was not switching. This was causing the UL sensor to have a different response, with a steeper roll of, which was causing all of the transfer function estimates to the other sensors to have large imaginary components. We took new free swing data with all of the whitening turned OFF. The result is a much improved matrix and diagnalization. The input matrix elements are mostly the same, but the coupling is basically gone. We'll fix the whitening after the pump down.
ITMY |
 |
pit yaw pos side butt
UL 0.157 1.311 1.213 -0.090 0.956
UR 1.749 -0.490 0.886 -0.038 -1.042
LR -0.251 -2.000 0.787 -0.007 1.066
LL -1.843 -0.199 1.114 -0.059 -0.936
SD -0.973 -0.205 1.428 1.000 0.239 |
4.34779 |
- ETMY has a very problematic SIDE OSEM. The magnet does not line up with the OSEM axis, and since there is no lateral adjustment in the side OSEMs, there's not much we can do about this. We're using aluminum foil to wedge the OSEM over as far as possible, but it's not quite enough. With the OSEM plates horizontal there is a lot of POS->SIDE coupling. With the OSEM plates vertical, the magnetic sits a little too close to the rear face, which can cause the magnet to get stuck to the LED plate. We're trying to decide where to leave it now, but the new diagnalization with the OSEM plates vertical is definitely better:
ETMX |
 |
pit yaw pos side butt
UL -0.138 1.224 1.463 -0.086 0.944
UR 0.867 -0.776 1.501 -0.072 -1.051
LR -0.995 -0.896 0.537 -0.045 0.754
LL -2.000 1.104 0.499 -0.059 -1.251
SD 0.011 0.220 1.917 1.000 0.224 |
4.42482 |
|
5290
|
Tue Aug 23 17:21:45 2011 |
kiwamu | Update | SUS | free swinging test for ETMY |
Excited ETMY
Tue Aug 23 17:20:45 PDT 2011
998180460
|
5291
|
Tue Aug 23 17:45:22 2011 |
jamie | Update | SUS | ITMX, 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 |
jamie | Update | SUS | SRM 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 |
 |
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 |
jamie | Update | SUS | ETMY 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 |
 |
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, steve | Update | SUS | ETMX 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, steve | Update | SUS | problem 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 |
jamie | Update | SUS | ITMX, ETMX, ETMY free swinging |
ITMX: 998245556
ETMX, ETMY: 998248032 |
5298
|
Wed Aug 24 16:13:36 2011 |
kiwamu | Update | SUS | broke 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 |
Jenne | Update | SUS | Broken 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 |
steve | Update | SUS | ETMY & 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 |
Jenne | Update | SUS | Drag 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 |
Jenne | Update | SUS | Broken 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 |
Suresh | Update | SUS | Broken 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 |
steve | Update | SUS | Broken 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 |
Jenne | Update | SUS | ITMX 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 |
Jenne | Update | SUS | ITMX 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 |
Jenne | Update | SUS | ITMX 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 |
Manuel | Configuration | SUS | SUS 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 |
jamie | Update | SUS | ITMY 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 |
steve | Update | SUS | BS & 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 |
kiwamu | Update | SUS | ITMY 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 |
steve | Update | SUS | why 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
|
|
Attachment 2: P8220152.JPG
|
|
5333
|
Thu Sep 1 15:59:46 2011 |
steve | Update | SUS | light 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 |
kiwamu | Update | SUS | ITMX 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 |
kiwamu | Update | SUS | Re: 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 |
steve | Update | SUS | ITMX 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
|
|
5342
|
Tue Sep 6 11:21:33 2011 |
Jenne | Update | SUS | ITMX 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 |
kiwamu | Update | SUS | free swinging test on ITMY |
Tue Sep 6 17:48:02 PDT 2011
999391697
|
5346
|
Tue Sep 6 17:56:12 2011 |
Jenne | Update | SUS | free 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 |
Jenne | Update | SUS | Diagonalizability 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 |
 |
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 |
 |
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 |
rana | Update | SUS | ITMX 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 |
Jenne | Update | SUS | Freeswing 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 |
steve | Update | SUS | final OSEM check |
All fine, except ITMX_sensor_UL's 60 counts deep hoop for an hour. |
Attachment 1: finalcheck.jpg
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Attachment 2: ITMX10min.jpg
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Attachment 3: finalsum.png
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|
5356
|
Wed Sep 7 09:21:57 2011 |
jamie | Update | SUS | SUS 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 |
 |
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 |
 |
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 |
 |
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 |
 |
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 |
 |
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 |
 |
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 |
 |
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 |
 |
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 |
 |
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 |
kiwamu | Update | SUS | OSEM 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 |
kiwamu | Update | SUS | free 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 |
rana | HowTo | SUS | Optical 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 |
steve | Update | SUS | PRM damping restored |
The PRM damping was restored at side sensor var 1050 |
5409
|
Wed Sep 14 20:30:36 2011 |
rana | Update | SUS | Some 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.

|
5411
|
Wed Sep 14 22:07:41 2011 |
rana | Update | SUS | ITM 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.

|
5415
|
Thu Sep 15 07:28:08 2011 |
steve | Update | SUS | PRM 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 |
kiwamu | Update | SUS | f2a 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
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Attachment 2: BS_f2a.png
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5418
|
Thu Sep 15 16:45:59 2011 |
Paul | Update | SUS | ITMY 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. |