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ID Date Author Type Categoryup Subject
  499   Sun May 25 22:33:00 2008 ranaUpdateSUSETMY Oplev Work
I found the ETMY table in disarray and put the panels back on and put the ETMY OL laser back on the quad.

The next thing to do is clean up the table (there's a lot of junk on it) and then put in a lens within
6" of the laser to focus the beam on the quad (no metal diving boards and the lens should be either
uncoated (from our Edmunds collection) or a red lens, not 1064).

Then we have to put the beam cover back on between the viewport and the table.
  504   Thu May 29 16:32:09 2008 steveUpdateSUSetmy oplev is back
I relayed the optics for ETMY-oplev as shown in pictures below.
The reflected beam goes directly to the qpd
Attachment 1: P1020417.png
Attachment 2: P1020420.png
  507   Fri May 30 12:37:45 2008 robUpdateSUSetmy oplev is back

I relayed the optics for ETMY-oplev as shown in pictures below.
The reflected beam goes directly to the qpd

I turned on the servo. UGFs in PIT and YAW are ~3Hz. I had to flip the sign of the YAW.
  629   Thu Jul 3 12:36:05 2008 JonhSummarySUSETMY watchdog
ETMY watchdog was tripped. I turned it off and re-enabled the outputs.
  676   Tue Jul 15 19:15:57 2008 ranaSummarySUSETMX Dewhitening characterization
Since the boys found that the ETM dewhitening transient was kicking the IFO out of lock we
decided to investigate.

First, we wrote a script to diagnose and then tune the DC gain of the dewhitening filters'
digital compensation filter (a.k.a. FM9 or SimDW). It is in the scripts/SUS/ directory
and is called dwgaintuner. It puts in an offset on each coil's DAC channel and
then reads back the Vmon on the coil driver with the DWF on and off. It reports the ratio of these
voltages which you can then type into the FM9/SimDW filter's gain field. We learned that the
difference between the analog DWF path and the bypass path was ~3% (which is consistent with
what you expect from the use of 1% resistors). We need to repeat this for all of the rest of
the suspended optics except for MC1 and MC3.

This Vmon method is better than what's used at the sites so we will export this new technology.

The attached plot shows some switching transients with only the local damping on:
BLUE:   Output of filter bank during an FM9 turn off. This is the transient which goes to the DAC.
        The transients are mostly of the same magnitude as this.
RED:    This is the input of the filter module during another such transient.
GREEN:  Tried another switch; this time I filtered the time series in DTT by typing the SimDW into
        the Triggered Time Series filter field. This should be simulating what comes out of the
        output of the DW board - to convert to volts multiply by 15/32768.
PURPLE: Same kind of filtering as the GREEN, but with also a double 30 Hz highpass to remove the low
        frequency damping control signals. You can see that the total transient is only ~5 counts
        or ~1 mV at the coil driver output. This is comparable to the relative offset in the bypass
        and filter paths.
Attachment 1: etmx-dw-transient.pdf
  755   Tue Jul 29 13:54:08 2008 ranaUpdateSUSETMY and PRM have EQ related problems
The attached trend shows that ETMY and PRM both had large steps in their sensors
around the time of the EQ and didn't return afterwards. The calibration of the
OSEM sensors is ~0.5 mm/V. The PRM sensors respond when we give it huge biases
but there is very little change in the ETMY. Almost certainly true that the
optics have shifted in their wire slings and that we will have to vent to
examine and repair at least ETMY.

Jenne is looking at the spectra of the other suspensions to see if there is
other more subtle issues.
Attachment 1: Untitled.png
  756   Tue Jul 29 14:38:02 2008 robUpdateSUSETMY and PRM have EQ related problems

The attached trend shows that ETMY and PRM both had large steps in their sensors
around the time of the EQ and didn't return afterwards. The calibration of the
OSEM sensors is ~0.5 mm/V. The PRM sensors respond when we give it huge biases
but there is very little change in the ETMY. Almost certainly true that the
optics have shifted in their wire slings and that we will have to vent to
examine and repair at least ETMY.

Jenne is looking at the spectra of the other suspensions to see if there is
other more subtle issues.

Some additional notes/update:

ETMY, PRM, & MC2 had OSEM signals at a rail (indicating stuck optics). Driving the optics with full scale DAC output freed ETMY and MC2, so while these may have shifted in their slings it may be possible to avoid a repair vent. PRM is still stuck. One OSEM appears to respond with full range to large drives, but the other three face OSEMS remain disturbingly near the rail (HIGH, which is what would happen if a magnet fell off).
  759   Tue Jul 29 19:53:19 2008 KojiUpdateSUSPRM photos from the south window
Steve and Koji

We took some photos of PRM from the south window.
You can see one of the side magnets, a wire stand-off, and the wire itself from the round hole.
So, the wire looks OK.

For the coils, we could see only one coil. The magnet is apparently too high.
Attachment 1: PRM_from_South_Window1.jpg
Attachment 2: PRM_from_South_Window2.jpg
  762   Wed Jul 30 00:42:04 2008 ranaUpdateSUSTrends and file formats
I propose that we do not use .eps format but .pdf instead. For images like the plots Sharon
has below we should use only .png and for pictures like what Steve posted, use JPG or PNG.

PDF is a standard and light weight. PNG is very good for plots/lines and is lossless. JPG does
a good job with regular camera pictures because we don't really care about the compression
loss on those.

Here's a trend of the UL sensors for all the optics - conversion is 32768 cts / mm. You can see
that the quake was just before 19:00 UTC (noon our time). The events an hour after are when
Rob, Jenne, and I start exciting the optics to shake them loose - wanging the pit/yaw sliders
around is not violent enough and so I injected a 130000 count sine wave at 0.5 Hz so as to
create a high force square wave. This seems to have worked for ETMY but no such luck yet with
the others.
Attachment 1: Untitled.png
  763   Wed Jul 30 01:08:50 2008 ranaSummarySUSSUS Drift Screen
This is a snap of the SUS Drift screen with all of the optics biases set back to their nominal
values except for the MC which Rob aligned and I didn't feel like mis-aligning. The reference
on the screen is from 3/25 when Andrey felt that Rob had a good IFO alignment.

Anything more than a few thousand is significant and more than 10k means something is wrong:

I wailed on the PRM for awhile and was able to loosen it up a little. The LL & LR sensors now
show some life one the dataviewer. The UL & UR are still railed ~1.6 V so that means that the
optic is pitched back. With aggressive pitch wailing I can see the PRM's ULR/UR sensors go
rail to rail so that means that the magnets are still on - although they may be half busted.
If they're OK we should be able to just re-sling this guy.

Did the same on SRM. The OSEM values have shifted on these, but not disastorously. The SIDE,
however, is completely unresponsive. The little signal I see when driving is is probably just
capacitive pickup in the cables. Have to vent to fix this one.

ITMX Has good life in all but the LR & UR channels. They respond, but the signal is very weak.
Seems like these magnets have not fallen off but that they are not between the LED/PD anymore.

ITMY seems ok. Check the spectra to be sure.

BS seems ok as well. Swings freely and no kinks in the swinging sensor waveforms. Check the spectra.
Attachment 1: infection-2.png
  773   Wed Jul 30 18:45:01 2008 ranaConfigurationSUSNew SUS Drift Technology
I updated the SUS DRIFT screen again, this time with a new feature.

I used Rolf's idea for the AdvLIGO status system and just made the nominals be an
unused sub-field (.SVAL) of the main INMON record. Then I wrote a .csh script to
use tdsavg to average the current INMON vals and insert that as the .SVAL. The next
script should read the .SVAL and set the HIHI and LOLO based on this.

Of course, the values I have just entered are no good because our suspensions are in
a bad state but we can run this script (SUS/setDriftNoms) next time things are good.

And...even better would be if someone were to do the same but used mDV to grab the
minute trend in the past good times instead of the tdsavg (which can't go in the past).
  785   Sat Aug 2 18:37:41 2008 ranaUpdateSUSOSEM Spectra

The attached PDF file is from the .xml files that I found from 7/30. Looks like someone
took some free swinging data and even made nice plots but didn't elog it. Raspberry for you.
The data files are saved in Templates/FreeSwinging/{ETMX,ETMY,etc.}/2008_07_30.xml

The top left plot on the multi-page file all have the same scale so you can see what's happened.
The peaks should all be as measured by Busby in Sep '06
but instead they are as you see here.
Attachment 1: free_080730.pdf
free_080730.pdf free_080730.pdf free_080730.pdf free_080730.pdf free_080730.pdf free_080730.pdf free_080730.pdf free_080730.pdf
  797   Tue Aug 5 10:23:00 2008 steveUpdateSUSearthquake and venting effects
atm 1, EQ
atm 2, vent 7 days later: venting kicks optic into place to be free,
PRM: LR magnet gets pushed in and it is stocked, side in free
Attachment 1: eq4h.jpg
Attachment 2: vent4hr.jpg
  799   Tue Aug 5 12:52:28 2008 YoichiUpdateSUSITMX, SRM OSEM spectra
Free swinging spectra of ITMX and SRM.
ITMX seems to be ok after yesterday's work, though the OSEM DC values are still a bit off from the normal value of 0.9.
(ITMX OSEM values: UL=1.12, UR=1.38, LR=0.66, LL=0.41, SIDE=0.66)
SRM is still clearly wrong.
Attachment 1: ITMX-2008_08_05-morning.pdf
Attachment 2: SRM-2008_08_05-morning.pdf
  803   Wed Aug 6 13:15:57 2008 YoichiUpdateSUSSRM ETMX freeswing spectra
After yesterday's work on the SRM, I took free swinging spectra of SRM.
The eigen modes look ok. But there are many other peaks which were not present in vacuum.
Some of those peaks may be resonances of the air inside the chambers and the pipes.
However, the peaks around 0.2Hz are too low frequency for those air compression modes.
I took the ETMX spectra at roughly the same time. I chose ETMX because we have not touched it after the vent.
ETMX also shows some extra peaks but the frequencies are different.
Attachment 1: SRM-ETMX-freeswing.pdf
SRM-ETMX-freeswing.pdf SRM-ETMX-freeswing.pdf
  806   Wed Aug 6 22:19:07 2008 YoichiUpdateSUSBS alignment
Koji, Yoichi

We realized that we did not pay attention to the BS alignment while working on the alignment of the ITMX today. Because we were injecting the ALM laser (absolute length measurement laser) from the AS port, the ITMX alignment depends on the BS alignment.
The BS optical lever was not centered and the sum was about 2000cnt, which is low compared, for example, to the SRM oplev.
So we were not sure if the BS was in a good alignment or not.
So we decided to move the BS to center the QPD.
In doing so, we also moved the ITMX so that we do not lose the ALM laser beam coming back to the AS port.
When the BS oplev was centered, the sum of the QPD was still about 2000. So it was not far off centered.
After the tweaking, we were able to see some interference between the light reflected by the ITMY and ITMX at the AS port (actually this is the bright port for the ALM laser). By tweaking the ITMY, we were able to see Michelson fringes at the AS port.
If we believe the ALM laser alignment is still good after the vent, the ITMX, ITMY, BS and SRM should be now in a good alignment condition.
The OSEM values for the ITMX, BS, SRM seem to be ok (0.9+/-0.2). The ITMY LL is a bit low (~ 0.45).
  807   Thu Aug 7 10:07:13 2008 YoichiUpdateSUSFree swinging OSEM spectra
Looks like there are more extra peaks in the SRM than other optics.
Maybe because it is closer to the door ?
Attachment 1: FreeSwingSpectra.pdf
FreeSwingSpectra.pdf FreeSwingSpectra.pdf FreeSwingSpectra.pdf FreeSwingSpectra.pdf FreeSwingSpectra.pdf FreeSwingSpectra.pdf FreeSwingSpectra.pdf FreeSwingSpectra.pdf
  808   Thu Aug 7 10:27:59 2008 ranaUpdateSUSFree swinging OSEM spectra
Sometimes we see extra peaks in the OSEM spectra coming from a beat between the regular eigenmodes.
This probably comes from the OSEM shadow sensor not being entirely linear - the nonlinearity is
greatly increased if the magnet is not perfectly centered in the LED beam. So the beats are
probably there at some level in all of them; usually below the noise.
  810   Thu Aug 7 12:20:52 2008 YoichiUpdateSUSPRM stand-offs and wire
We removed the side OSEM of the PRM so that we can see the stand-off on the farther side.

Attachment 1: Farther side stand-off from an angle before removing the OSEM
Attachment 2: Farther side stand-off through the empty OSEM hole.
Attachment 3: Near side stand-off

The wire is definitely in the near side stand-off groove.
Probably the wire is in the groove also on the farther side.
Attachment 1: IMG_1456.JPG
Attachment 2: IMG_1478.JPG
Attachment 3: IMG_1470.JPG
  811   Thu Aug 7 17:32:23 2008 JenneUpdateSUSAfternoon PRM activities
Rana, Jenne, Yoichi, Dmass

After Yoichi confirmed this morning that the wire was in both grooves, Rana attempted to lift the PRM a tiny bit, and twist it around (very gently of course) to see if we could make the wire slip back to its nominal position underneath the optic. On the first attempt, the wire ended up slipping the wrong way, causing slightly more tilt. On another attempt, the wire came out of the groove nearest the chamber door by about 0.5mm. We got the wire back in the groove by slightly lifting the optic, and pushing the wire back in. Then, on further attempts at making the wire slip back to its nominal position, the wire came out of the groove farthest from the chamber door. It is very difficult to get at that side of the PRM, because the table is crowded, and it is on the far side of the optical table from the chamber door. We decided to pull the PRM out of the chamber. Rana clamped the mirror into its cage using the earthquake stops and removed the OSEMS, and then we pulled the mirror out. We put it on a cart that was covered with foil and had a little foil house for the optic cage. We rolled the mirror+cage over to the flow bench at the end of the y-arm.

We saw that the wire is no longer even on the standoff (~3mm away from the groove) on the side that was farthest from the chamber door.

Since we have not confirmed that we have spare wire and spare magnets (and due to the time of day), we have decided to cover the cage with some foil, while it is sitting on the flow bench, and we'll fix the wire in the morning.
  816   Fri Aug 8 13:29:54 2008 YoichiUpdateSUSNo groove in the stand-off ... wait, it is not even a stand-off !
Yoichi, Steve, Seiji

We took magnified pictures of the stand-offs of the PRM.
Attm1: North side stand-off.
Attm2: South side stand-off.
Attm3: Zipped file of the full pictures.

We found no groove in the south side stand-off.
After some discussion, we concluded that it is actually a guide rod. You can see it from the size difference (the magnification is the same for the two pictures).
The stand off on the south side is missing (fell off, ran away, evaporated or whatever ...).
Also we noticed that the guide rod on the north side is missing.

We have to find a stand-off and place it on the south side.
Seiji suggested that it is better to put a guide rod next to the north side stand-off, otherwise the stand-off itself is too weak to hold the load.
He also said that the PRM was installed after he left, so it was not his fault.
Attachment 1: north-standoff-preview.jpg
Attachment 2: south-standoff-preview.jpg
Attachment 3: No-groove.zip
  817   Fri Aug 8 15:10:35 2008 YoichiUpdateSUSNo groove in the stand-off ... wait, it is not even a stand-off !
I tried to find the missing stand-off and the guide rod in the BS chamber, but I couldn't.
  818   Fri Aug 8 17:54:52 2008 JenneUpdateSUSStandoffs and Guide Rods
After closer inspection of other small optics, it is clear that the guide rods should be above the standoffs on our small optics. Yoichi took a picture of the SRM that shows this clearly. This makes sense since the tension of the wire will make the standoff 'want' to go up during pre-epoxy adjustment, so the guide rod prevents the standoff from popping up and out.

Looking at the side of the PRM without the groove, it looks like there is lots of space between the guide rod and the alignment etch in the glass, so we can just place a standoff directly under the guide rod that is present.

A spare standoff is being shipped tomorrow morning, so we should have it by Monday for installation on the PRM.
Attachment 1: SRM_Standoff_and_guide.JPG
  831   Wed Aug 13 17:00:59 2008 steveConfigurationSUSBS sat amp removed
The PRM sat amp is broken. Ben is working on it.
The BS sat amp was removed from the BS sus and it is used with the PRM in
order to damp it for wire stand-off alignment.
  832   Wed Aug 13 20:13:35 2008 YoichiUpdateSUSPRM stand-off is glued
Steve, Janne, Rob, Bob, Koji, Yoichi

We finally managed to balance the PRM and the stand-off is now glued.

The whole procedure was something like this:

(1) Measure the levelness of the optical table. It was done by a bubble level claiming that
the sensitivity is 60 arcsec (roughly 0.3 mrad).
There was no noticeable tilt along the longitudinal direction of the table.

(2) We put a He-Ne laser on one end of the table. Mounted a QPD on a X-Y-Z stage. Put the QPD very
close to the laser and centered it by moving the QPD.
Then we moved the QPD far away from the laser and centered the beam spot in vertical direction
by changing the tilt of the laser mount.
We then moved the QPD close to the laser again and adjusted the height to center it. By repeating
the centering at two locations (near and far) several times, we aligned the laser beam parallel to
the table.

(3) The PRM suspension tower was put on the other end of the optical table, i.e. far from the laser.
The QPD was moved next to the laser to form an optical lever. The height of the QPD is preserved from
the previous step.

(4) A stand-off was picked by a pair of tweezers. By gently lifting the mirror by the bottom earthquake stops,
the tension of the wire was relieved. Then the stand off was slid in below the guide rod.

(5) Using the microscope, it was confirmed that the wire is in the grooves on both sides.

(6) Without damping, it was too much pain to balance the mirror. So we put spare OSEMs in the suspension and
pulled a long cable from the suspension rack to the clean room with a satellite amp.

(7) It turned out that the pinout of the cable is flipped because of the vacuum feed through. So we asked Ben for help.
He made conversion cables. We also found UR OSEM was not responding. Ben opened the satellite box, and we found an op-amp was burnt.
Probably it was because we connected OSEMs wrongly at first and the LED current driver was shorted. We switched the satellite box
from the PRM one to the BS one. Ben will fix the PRM box.
Bob cleaned up some D-Sub converters for the interface with the clean OSEM pigtails.

(8) While waiting for Ben, we also tried to short the OSEM coils for inductive damping. We saw no noticeable change in the Q.

(9) After the OSEMs were connected to the digital control system, Rob tweaked the damping gains a bit to make it work efficiently.

(10) I pushed the stand-off back and forth to make the reflected beam spot centered on the QPD. I used the PZT buzzer to gently move the stand-off.
For fine tune, just touching it is enough. I found it useful to touch it without clamping the mirror, because if it is clamped, we can easily push
it too hard. When the mirror is freely hanging, once the tip of the buzzer touches the stand-off, the mirror escapes immediately. If the mirror
swings wildly by your touch, you pushed it too hard.

(11) After about an hour of struggle, I was able to level the mirror. We used about 1.5m optical lever arm. A rough calibration tells us that the
beam spot is within 0.6mm of the center of the QPD. So the reflected light is deflected by 0.4mrad. That means the mirror
is rotated by 0.2mrad. The OSEMs should have about 30mrad of actuation range. So this should be fine.

(12) We mixed the Vac Seal epoxy and put it under vacuum for 15min to remove bubbles. Actually 15min was not enough for removing bubbles completely. But
stopped there because we did not want the epoxy to be too stiff.
I dipped a thin copper wire into the epoxy and applied it on the top of the stand-off. I found the epoxy is already not fluid enough, so Steve made
another Vac Seal mixture. This time we put it under vacuum for only 3 min.
I also applied the epoxy to the sides of the stand-off.
While working on this, I accidentally touched the side of the PRM. Now there is a drop of epoxy sitting there (upper left of the attached picture).
We decided not to wipe it out because we did not want to screw up the levelness.

(13) We put an incandescent light about 1m away from the suspension to gently warm up the epoxy but not too much. We will leave it overnight to cure the
Attachment 1: img1.jpg
  833   Thu Aug 14 10:26:45 2008 steveHowToSUSsus cable pin cheater for out of vac damping
The 40m D25 vacuum feed troughs give you a mirror image pin count.

Sus damping outside of the vacuum envelope require this cheater cable where
on the male D pin 1 is connected to female D 13 and so on
and male D pin 14 is connected to female D 25 and so on
Attachment 1: suscabmin.png
  836   Thu Aug 14 19:08:14 2008 YoichiConfigurationSUSFree swing measurement going on
I started free swinging spectra measurement of all the suspensions now Aug 14 19:05 (PDT).
The watch dogs are all shutdown. Please do not turn them back on until tomorrow morning.
  842   Fri Aug 15 17:38:41 2008 YoichiUpdateSUSOSEM free swinging spectra before the pump down
I ran an overnight measurement of the free swinging OSEM spectra.
The attm1 shows the results. Everything look ok except for the ITMY UL OSEM.
The time series from that OSEM was very noisy and had many spikes.
We suspected the cable from the satellite box to the computer rack because we disconnected the cable
when we tested a spare cable which was used to connect the spare OSEMs to the PRM suspension in the clean room.
Janne remembered when she put the cable back, she trusted the latch on the connector and did not push it in too hard.
However, Rob suggested the latch does not work well. So she pushed the connector again. Then the signal from
the ITMY UL OSEM got back to normal.
The second attachment shows the ITMY spectra after the cable push.
We decided to pump down after confirming this.

There are still a lot of extra peaks especially in the suspensions in the BS chamber.
These may be inter modulations (by the non-linearities of the OSEMs) of the modes of the multiple
suspensions sitting on the same stack.
Attachment 1: 2008-8-15.pdf
2008-8-15.pdf 2008-8-15.pdf 2008-8-15.pdf 2008-8-15.pdf 2008-8-15.pdf 2008-8-15.pdf 2008-8-15.pdf 2008-8-15.pdf
Attachment 2: ITMY2.pdf
  844   Mon Aug 18 08:07:10 2008 YoichiConfigurationSUSSuspension free swinging
I've started a free swinging measurement of OSEM spectra now. Please leave the watchdogs untouched.
  846   Mon Aug 18 11:50:29 2008 YoichiUpdateSUSIn vacuum free swinging results
The first attachment is the results of the free swinging spectra measurement performed in vacuum this morning.
They are freely swinging, but the suspensions in the BS chamber got even more extra peaks.
Especially, the SRM spectrum looks like a forest.
If those extra peaks are inter-modulations of the primary suspension modes, the heights of them should be
enhanced (compared to the in-the-air case) by the increased quality factors of the primary modes (due to the less air friction).
This might explain the observed increase in the extra peaks.

While doing the free swinging, we had two big spikes in the OSEM signals of the ETMs and only in ETMs.
Those spikes screwed up the spectra of the ETMs. So the ETM spectra were calculated using the time series
after the spikes.
The second attachment shows one of those spikes. It looks like a computer glitch.
Attachment 1: 2008-8-18.pdf
2008-8-18.pdf 2008-8-18.pdf 2008-8-18.pdf 2008-8-18.pdf 2008-8-18.pdf 2008-8-18.pdf 2008-8-18.pdf 2008-8-18.pdf
Attachment 2: spike.pdf
  851   Tue Aug 19 13:12:55 2008 JenneUpdateSUSDiagonalized PRM Input Matrix
NOTE: Use the values in elog #860 instead (20Aug2008)

Using the method described in LIGO-T040054-03-R (Shihori's "Diagonalization of the Input Matrix of the Suspension System"), I have diagonalized the input matrices for the PRM.

Notes about the method in the document:
  • Must define the peak-to-peak voltage (measured via DataViewer) to be NEGATIVE for PitLR, PitLL, YawUR, YawLR, and POSITIVE for all others
  • As Osamu noted in his 3 Aug 2005 elog entry, all of the negative signs in equations 4-9 should all be plus.

New PRM Input Matrices:

UR1.18771.0075 -1.0135
LR0.8439 -0.9425 -0.9653
LL0.9684 -1.05001.0216
  860   Wed Aug 20 12:04:47 2008 JenneUpdateSUSBetter diagonalization of PRM input matrix
The values here should replace those in entry #851 from yesterday.

After checking the results of the input matrix diagonalization, I have determined that Sonia's method (described in LIGO-T070168) is more effective at isolating the eigenmodes than Shihori's method (LIGO-T040054).

So, the actual new PRM input matrices are as follows:

UR1.0000.8025 -0.9993
LR0.7235 -1.1230 -1.0129
LL0.6648 -1.04521.0000

Attached are plots of the spectra of the eigenmodes, using both Shihori's and Sonia's methods. Note that there isn't a good way to get the side peak out of the eigenmodes.

I've put these into the SUS-PRM MEDM screen.
Attachment 1: PRM_Eigmodes_shihori.png
Attachment 2: PRM_Eigmodes_sonia.png
  869   Fri Aug 22 10:39:41 2008 JenneUpdateSUSTaking Free Swinging spectra of PRM, SRM, ITMX, BS
I'm taking free swinging spectra of PRM, SRM, ITMX and BS, so I've turned off their watchdogs for now. I should be done around 11:15am, so I'll turn them back on then.
  970   Fri Sep 19 01:55:41 2008 ranaSummarySUSSUS Drift Screen Updated
I wrote 2 matlab scripts to update the SUS DRIFT screen:
- setsval.m   uses mDV to get the minute trend from some specified start time
              and duration in the past. It then writes that 'good' value to the
              .SVAL field of the SUSPOS, SUSPIT, and SUSYAW records for all the

- setHILO.m   reads the .SVAL field and then sets the alarm levels and severity
              for the same records given a "sigma" as an argument. i.e. 1 sigma = HIGH,
              2 sigma = HIHI.

Attached is the new screen. WE can now use this to judge when the optics have moved alot.

If someone will edit the BURT .req file to have these subfields
(.HIHI .HIGH .LOW .LOLO .HHSV .HSV .LSV .LLSV) then they will come back after a reboot as well.

Below I'm also attaching the matlab code for people at the observatories who don't have
access to the SVN here.
Attachment 1: infection-3.png
Attachment 2: setsvals.m
function varargout = setsvals(varargin)
% sets the SVAL records for the SUS

debug = 0;

if nargin < 2
  error('Needs 2 arguments.')
elseif nargin > 2
... 56 more lines ...
Attachment 3: setHILO.m
function setHILO(varargin)
%  Ex.  setHILO(1000);
%      this sets the SUS alarm levels to be 1000 counts
%      from the nominal

% 1 for debugging
debug_flag = 0;

if nargin == 1
... 62 more lines ...
  975   Mon Sep 22 12:06:58 2008 robUpdateSUSITMY UL OSEM

Last week I found the ITMY UL OSEM dead. I went around and checked the connections on the various flat ribbon cables
in the suspension control chain; pushing hard on the rack end of the long cable that goes from the sus electronics rack to the
ITMY sat amplifier fixed the problem. It's been fine since then.

NB: A visual inspection of the cable connection would not have revealed a problem. You just can't trust those flat
ribbon connectors with the hook latches.
  996   Fri Sep 26 09:05:47 2008 steveUpdateSUSMC2 damping restored
The MC2 sus damping was restored.
  1021   Thu Oct 2 18:56:19 2008 ranaSummarySUSResistivity of Suspension Wire
Bob and Steve measured the resistance of the suspension wire today:
OD     = 0.0036" =  0.091 mm
Length = 46"     = 1168.4 mm
Resistance     =   33.3 Ohms

resistivity = R * pi * (OD/2)^2
              ----------------- = 1.85e-7 Ohm-meters

This was a batch of California Fine Wire from 2001 (same as used at LHO and LLO).

By comparison the standard tabulated resistivity for steels is (http://hypertextbook.com/facts/2006/UmranUgur.shtml):
                  resistivity (Ohm-meter x 10^-7)
-------------     ----------------
304 Stainless       7.2
316 Stainless       7.4
Cast Steel          1.6

This is all to see whether or not the 60 Hz fields produce forces on the suspension wires via coupling with the Earth's DC field.

  1103   Fri Oct 31 08:52:19 2008 steveUpdateSUSETMY damping restored
ETMY watchdogs were tripped yesterday morning also. This is a problem that existed some months ago.(?)
Our seimo channels are inactive.
Attachment 1: etmy2d.jpg
  1188   Mon Dec 8 17:50:21 2008 YoichiUpdateSUSITMY drift
The suspension drift monitor shows that the ITMY alignment was shifted after the earthquake.
Looks like only the UL sensor had a step at the earthquake (see the attachment 1).
So it is probably an electronics problem.
I pushed in the cable between the rack and the ITMY satellite amplifier, but no change observed.
Actually, the ITMY-UL sensor looks like it has been dead before the earthquake.
The second attachment shows a long-term trend of the UL sensor.
The sensor output had been around zero since Nov. 17th.
When I disabled the output of the UL sensor, the sus-drift-mon fields turned green.
So I think the drift-mon's reference values are wrong, and currently the ITMY is in a good alignment.

I also attached the free-swing measurements of the ITMY taken on Aug. 18th and today.
There is no notable change in the resonant frequencies.
Attachment 1: ITMY-OSEMs.png
Attachment 2: ITMY-UL.png
Attachment 3: ITMY-08-18.pdf
Attachment 4: ITMY-12-08.pdf
  1192   Thu Dec 18 12:52:00 2008 AlbertoConfigurationSUSMode Cleaner Cavity Alignment
This morning I found the MC locked to the 10 mode. When I locked it on the 00 mode, it was unstable and eventually it always got locked to the wrong mode.

I looked at the Drift Mon MEDM screen, which shows a reference record for position, pitch and yaw of each mirror, and I found that the MC optics were in a different status. Moving the sliders of the mirrors' actuators, I brought them back to the reference position. Then the lock got engaged and it was stable, although the MC reflection from the photodiode, with the wave front sensors (WFS) off, was about 2V. That's higher than the 0.5V the it could get when we aligned the cavity and the input periscope last time.

With the WFS on, the reflection dropped to 0.3V and, so far, the the cavity has been stably locked.
  1193   Thu Dec 18 19:15:54 2008 Alberto, YoichiConfigurationSUSMode Cleaner Cavity Alignment

This morning I found the MC locked to the 10 mode. When I locked it on the 00 mode, it was unstable and eventually it always got locked to the wrong mode.

I looked at the Drift Mon MEDM screen, which shows a reference record for position, pitch and yaw of each mirror, and I found that the MC optics were in a different status. Moving the sliders of the mirrors' actuators, I brought them back to the reference position. Then the lock got engaged and it was stable, although the MC reflection from the photodiode, with the wave front sensors (WFS) off, was about 2V. That's higher than the 0.5V the it could get when we aligned the cavity and the input periscope last time.

With the WFS on, the reflection dropped to 0.3V and, so far, the the cavity has been stably locked.

This evening the mode cleaner was again locking on a higher mode so we tweaked the mirrors' actuators by their sliders on the MEDM screen until we improved the reflection to 0.3V.

Then we went inside and, on the AS table, we centered the beam on the wave front sensors.

Now the mode cleaner is locked, the reflection is less than 0.3V and the transmission about 3V, tha is it is in ideal conditions. We'll see if it holds.
  1234   Fri Jan 16 18:29:08 2009 YoichiUpdateSUSOplevs QPDs centered
Kakeru centered ITMX and BS optical levers with the help of Jenne on the walkie-talkie.
  1314   Mon Feb 16 22:58:51 2009 rana, yoichiConfigurationSUSHysteresis in SUS from Misalignments
WE wondered if there was some hysteresis in the SUS alignments. When we leave the optics misaligned for a
long time it seems to take awhile for the optic to settle down. Possibly, this is the slow deformation of
the wires or the clamps.

The attached PNG shows the plot of the bias sliders for a few days. You can see that we misalign some of the
optics much more than the others. This must be stopped.

Kakeru is going to use his nearly complete optical lever calibrations to quatify this by stepping the optics
around and measuring the effect in the optical lever. Of course, the misalignment steps will be too large to
catch on the OL, but he can calibrate the align-sliders into radians to handle this.
Attachment 1: a.png
  1420   Tue Mar 24 09:04:02 2009 steveUpdateSUS4.8 mag earthquake

SRM, ITMX, ETMX, ITMY and ETMY lost damping at 4:55am this morning from 4.8 magnitude earthquake.

Their damping were restored.

C1:SUS-ITMX_URSEN_OUTPUT swich was found in off position. It was turned on.

MZehnder  and MC were locked.

The WFS qpd spot needs recentering

  1422   Tue Mar 24 13:54:49 2009 JenneUpdateSUSOp Levs Centered

ITMX, ITMY, BS, SRM, PRM op levs were all recentered.  ETM's looked okay enough to leave as-is. 

  1439   Sun Mar 29 13:44:27 2009 steveUpdateSUSETMY sus damping restored

ETMY sus damping was found to be tripped.

It was retored.

All fluorecent light were turned off. Please try to conserve some energy.

  1440   Sun Mar 29 17:54:41 2009 YoichiUpdateSUSMC1 drift investigation continued
The attached plots show the trend of the MC OSEM signals along with the voltages across the output resistors of the bias current buffers.
The channel assignments are:
MC_TMP1 = LL coil
MC_DRUM1 = UL coil

Although the amplitude of the drift of MC1 is much larger than that of MC2 and MC3, the shape of the drift looks like a daily cycle (temperature ?).
This time, I reduced the MC1 bias currents to avoid saturation of the ADCs for the channels measuring the voltages across the output resistors.
This may be the reason the MC1 has been non-glitchy for the last day.

OSA_APTEMP (UR Coil) shows a step function like behavior, although it did not show up in the OSEM signals.
This, of course, should not happen.

Today, I went to the MC1 satellite box and found that the 64-pin IDE like connector was broken.
The connector is supposed to sandwich the ribbon cable, but the top piece was loose.
The connector is on the cable connecting the satellite box and the SUS rack.
I replaced the broken connector with a new one. I also swapped the MC1 and MC3 satellite boxes to see if the glitches show up in the MC3.

I restored the bias currents of the MC1 to the original values.

The probes to monitor the voltages across the output resistors are still there. For OSA_SPTEMP, which was saturating the ADC, I put a voltage divider before the ADC. Other channels were very close to saturation but still within the ADC range.

Please leave the MC unlocked at least until the Monday morning.
Also please do not touch the Pomona box hanging in front of the IOO rack. It is the voltage divider. The case is connected to the coil side of the output resistor. If you touch it, the MC1 bias current will change.

Attachment 1: Drift1.pdf
  1441   Mon Mar 30 09:07:22 2009 ranaUpdateSUSMC1 drift investigation continued
Maybe we can temporarily just disconnect the bias and just use the SUS sliders for bias if there's enough range?
  1444   Mon Mar 30 13:29:40 2009 YoichiUpdateSUSMC1 drift investigation continued

Maybe we can temporarily just disconnect the bias and just use the SUS sliders for bias if there's enough range?

We could do this, but I'm suspicious of the cables between the coil driver and the coils (including the satellite box). In this case, disabling the bias won't help.
Since the MC1 has been quiet recently, I will just lock the MC and resume the locking.
  1583   Wed May 13 21:15:04 2009 ranaSummarySUSChannel Hopping: That ancient enemy (MC problems)
The MC side problem could also be the side tramp unit problem. Set the tramp to 0 and see if that helps.
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