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ID Date Author Type Categoryup Subject
  5972   Mon Nov 21 17:48:36 2011 KojiUpdateIOORFAM monitoring test

Do we care about the AC? I thought what we care is the DC.

  5975   Tue Nov 22 04:02:47 2011 kiwamuUpdateIOOchanged MC alignment

I have changed the MC2_YAW DC bias because the PZT1_YAW was railing.

I also realigned the steering mirrors in zig-zag path since the mode cleaner tended to resonate with higher order modes after I have changed the MC2 bias.

  C1:SUS-MC2_YAW_COMM =  -1.1548    => -1.1208

  5981   Tue Nov 22 20:45:21 2011 MirkoUpdateIOOMeasurement of the actuator matrix

Tried measuring the actuator matrix for MC1.

With the watchdogs tripped I cut the loops for pos, pitch and yaw open just before the servos. Then I injected a fixed sine at 0.4Hz into the three DOFs (suspos, suspit, susyaw) one by one, while looking into the error signal just before the servos.

 

                                                         Response DOF

                                     pos                 pit             yaw

Injection DOF pos          0.008417       0.00301        0.004975
                     pit            0.01295         0.01959        0.0158
                     yaw         0.007188        0.002152     0.0144

Inverting that and dividing by the norm gives us

 0.8322   -0.1096   -0.1669
-0.2456    0.2869   -0.2293
-0.3777    0.0118    0.4211

Somehow putting this into the 'To coil' matrix has an effect even with the watchdog tripped!?!?

 

  5990   Wed Nov 23 16:55:57 2011 SureshUpdateIOOMC realigned

The PSL alignment into the MC was too poor for the autolocker to engage.  So retaining the last coil slider settings on the MC_Align screen that Kiwamu wanted, I have realigned the PSL beam and recentered the beam on the WFS.

When the WFS_MASTER was burtrestored after the recent power shutdown, the values loaded into the output matrix were not optimal.  When we switch on the WFS loops now, the MC_TRANS loops seem to push the WFS into away from the best possible coupling to PSL.  So I have switched them off for now.   Will load a new optimised output matrix and measure the transfer functions to see what is going on.

 

 

  5991   Wed Nov 23 18:28:09 2011 KojiUpdateIOORFAMPD channels / EOM monitor channels added to DAQ

The following channels have been registered in c1iool0 database, and are now recorded by FB

C1:IOO-RFAMPD_11MHZ
C1:IOO-RFAMPD_29_5MHZ
C1:IOO-RFAMPD_55MHZ
C1:IOO-RFAMPD_DCMON
C1:IOO-EOM_TEMPMON
C1:IOO-EOM_HEATER_DRIVEMON


PROCEDURE

1) The EPICS database file has been edited to rename/add some channels

/cvs/cds/caltech/target/c1iool0/ioo.db

REMOVED
#grecord(ao,"C1:IOO-RFAMPD_VC")
#grecord(ai,"C1:IOO-RFAMPD_TEMP")
#grecord(ai,"C1:IOO-RFAMPD_DCMON")
#grecord(bo,"C1:IOO-RFAMPD_BIAS_ENABLE")
#grecord(bi,"C1:IOO-RFAMPD_BIAS_STATUS")
#grecord(calc, "C1:IOO-RFAMPD_33MHZ_CAL")
#grecord(calc, "C1:IOO-RFAMPD_133MHZ_CAL")
#grecord(calc, "C1:IOO-RFAMPD_166MHZ_CAL")
#grecord(calc, "C1:IOO-RFAMPD_199MHZ_CAL")

ADDED/EDITED
grecord(ai,"C1:IOO-RFAMPD_11MHZ")
        field(DTYP,"VMIVME-3113")                                              
        field(INP,"#C1 S25 @")
...

grecord(ai,"C1:IOO-RFAMPD_29_5MHZ")
        field(DTYP,"VMIVME-3113")                                              
        field(INP,"#C1 S26 @")

...
grecord(ai,"C1:IOO-RFAMPD_55MHZ")
        field(DTYP,"VMIVME-3113")                                              
        field(INP,"#C1 S27 @")

...
grecord(ai,"C1:IOO-RFAMPD_DCMON")
        field(DTYP,"VMIVME-3113")                                              
        field(INP,"#C1 S28 @")

...
grecord(ai,"C1:IOO-EOM_TEMPMON")
                                                
        field(DTYP,"VMIVME-3113")                                               
        field(INP,"#C1 S29 @")

...
grecord(ai,"C1:IOO-EOM_HEATER_DRIVEMON")

        field(DTYP,"VMIVME-3113")                                              
        field(INP,"#C1 S30 @")

2) The channels have been added to the frame builder database

/cvs/cds/rtcds/caltech/c1/chans/daq/C0EDCU.ini

[C1:IOO-RFAMPD_11MHZ]
[C1:IOO-RFAMPD_29_5MHZ]
[C1:IOO-RFAMPD_55MHZ]
[C1:IOO-RFAMPD_DCMON]
[C1:IOO-EOM_TEMPMON]
[C1:IOO-EOM_HEATER_DRIVEMON]

Note that this C0EDCU.ini is the file that has been registered in

/cvs/cds/rtcds/caltech/c1/target/fb/master

3) burt restore request files were updated

RFAM related settings were removed as they don't exist anymore.

/cvs/cds/caltech/target/c1iool0/autoBurt.req
/cvs/cds/caltech/target/c1iool0/
saverestore.req

4) c1iool0 were rebooted. Framebuilder restarted. c1iool0 were burtrestored.

  5995   Thu Nov 24 05:10:00 2011 KojiUpdateIOORFAMPD channels / EOM monitor channels added to DAQ

EOM TEMPMON and HEATER DRIVEMON have been hooked up to the following channels.

C1:IOO-EOM_TEMPMON
C1:IOO-EOM_HEATER_DRIVEMON 

What a fragile circuit...

I found some of the resistors popped up from the board because of the tension by the Pomona grabbers.
I tried to fix it based on the schematic (photo) and the board photo.

  5996   Thu Nov 24 05:47:16 2011 KojiSummaryIOOStochmon running

Now stochmon for 11MHz and 55MHz is running. The calibration / noise measurement are going to be post later...

  5997   Thu Nov 24 10:27:07 2011 JenneUpdateIOORFAMPD channels / EOM monitor channels added to DAQ

Here is a drawing of where the monitors are coming from:

EOM_temp_sense_heater_drive_schematic_withMONs.png

 Since we can't put current into the ADC, the heater drivemon is measuring the input of the OP27, which is related to the amount of current sent to the heater.

Quote:

EOM TEMPMON and HEATER DRIVEMON have been hooked up to the the following channels.

C1:IOO-EOM_TEMPMON
C1:IOO-EOM_HEATER_DRIVEMON

 

  5998   Thu Nov 24 12:45:12 2011 ZachUpdateIOORFAMPD channels / EOM monitor channels added to DAQ

Jenne: The point you indicate for the heater monitor is a virtual ground--it will be driven to zero by the circuit if it's functioning properly; the readout should be done at the input pin (2, I think) to the BUF634.

Koji: This is odd, as I made a point of not attaching any clips directly to resistors for exactly this reason. I was also careful to trim resistor/capacitor leads so that they were not towering over the breadboard and prone to bending (with the exception of the gain-setting resistor of the AD620, which was changed at the last minute). At the end of the day, it is a breadboard circuit with Pomona "readout", so it's not going to be truly resilient until I put it on a protoboard. Another thing: I think the small Pomona clips are absolutely terrible, since they slip off with piconewtons of tension; I could not find any more regular clips, so I used them against my better judgment.

  5999   Thu Nov 24 13:54:31 2011 KojiUpdateIOORFAMPD channels / EOM monitor channels added to DAQ

Those clips for the readouts were the ones who popped out.
When I have restored the connections, I checked the schematic and the heater drive mon is clipped on the output side of the OP27.

Quote:

Jenne: The point you indicate for the heater monitor is a virtual ground--it will be driven to zero by the circuit if it's functioning properly; the readout should be done at the input pin (2, I think) to the BUF634.

Koji: This is odd, as I made a point of not attaching any clips directly to resistors for exactly this reason. I was also careful to trim resistor/capacitor leads so that they were not towering over the breadboard and prone to bending (with the exception of the gain-setting resistor of the AD620, which was changed at the last minute). At the end of the day, it is a breadboard circuit with Pomona "readout", so it's not going to be truly resilient until I put it on a protoboard. Another thing: I think the small Pomona clips are absolutely terrible, since they slip off with piconewtons of tension; I could not find any more regular clips, so I used them against my better judgment. 

 

  6004   Thu Nov 24 20:22:42 2011 MirkoUpdateIOOF2A filter for MC

I calculated the F2A filters for the input mode cleaner optics as described in T010140-01-D eq (4). On Ranas recommendation I added an s/ ( w_0 * Q ) term to the numerator.

The used values are:

w_0 = 2pi / s
h= 0.0009
D= 2.46957E-2
Q=10

UpperCoils.pdf

LowerCoils.pdf

I put theses filters into C1:SUS-MC1_TO_COIL_1_1 to _4_1 . For convenience split in Z and P. Well it doesn't work. After a few seconds the optic begins to swing wildly.

  6006   Fri Nov 25 17:52:28 2011 ranaUpdateIOOF2A filter for MC

Woo. Pretty crazy. The numerators should only be ~10% larger than the denominator below 1 Hz. Let's try again.

  6009   Fri Nov 25 20:03:05 2011 KojiUpdateIOOStochmon update

 New RFAM mon calibration

  6012   Fri Nov 25 23:25:24 2011 MirkoUpdateIOOF2A filter for MC

Quote:

Woo. Pretty crazy. The numerators should only be ~10% larger than the denominator below 1 Hz. Let's try again.

 [Rana, Mirko]

I redid this calculation. The idea behind it is to get rid on any pitch that is introduced by applying longitudinal feedback to the mirrors. This coupling happens because the center of percussion for pitch , which is identical with the point where the wires lift off of the mirror, is above the center of mass.

With the same values as before, just less faulty math and Q = 2 instead of 10 we end up with the following filters:

For the lower coils (red), compared to corresponding preexisting BS filters (black):

F2aForMCcomparedToBS.pdf

The upper coils' TF is just mirrored at the 0dB magnitude axis, and have a corresponding frequency response.

I switched the F2a filters on for all MC mirrors. For convenience they are split into F2aZeros and F2aPoles. Everything seems fine. The F2a filters seem to be off for ( all ?) other mirrors.

  6015   Sat Nov 26 07:18:11 2011 SureshUpdateIOOMC WFS related changes to c1ioo model

What I did:

    I have changed the c1ioo model such that the signals which are demodulated in the WFS lockin (the SIG inputs) are now picked up just after the input matrix.  This permits us to put a notch filter at the excitation frequency into the WFS servo filterbanks and thus prevent the excitation of all the actuators when we wish to excite just one of them. 

 

The Problem:

    I had followed the procedure of determining the TF coefs between actuators (MC1,2,3 P and Y ) and sensors (WFS1, 2 and MC2Trans P and Y)  and found the output matrix by inverting this TF coef matrix. However these matrices, once substituted for the heuristically determined matrices were always unsuccessful in keeping the WFS servo lock.  The reason appeared to be that when the loops are closed the exitation of one actuator led to the excitation of all actuators through the cross couplings in the output matrix.    In order to prevent this we need a notch filter in the servo filter banks.   But then we will not be able to see the sensor response after the servo filters since the response at 10Hz would be blocked from reaching the lockins.  So I shifted the point at which we sample the sensor response to a point before the WFS servo filters. 

The solution:

a) shift the point where the lockin input signals are picked up in the c1ioo model.

b) retune the lockin servo phases to minimise Q phase

c) edit the WFS lockin scripts to ensure that the 10Hz notch is turned on

d) measure the TF coefs and compute the -1*inverse

e) plug it into the output matrix and tweak the gains to ensure a stable lock

f) examine cross talk by comparing the expected TF in each loop with the expected loop TF.

 

Current state:

  I have completed steps a to e above.  The loops are stable and the error signal is suppressed (see attached pdf files)

To be done:

  The open loop transfer function has to be compared with expected OLTF to be sure we have minimised cross talk.

 

  6028   Mon Nov 28 18:19:53 2011 kiwamuUpdateIOOStochmon seems working

Here is a 48 hours trend of the RFAM monitor (a.k.a StochMon):

RFAM_48hours.png

The upper plot is the DC output from the StochMon PD and the lower plot shows the calibrated RIN (Relative Intensity) at each modulation frequency.

I have downloaded minutes trends of StochMon for 48 hours staring from 6:00AM of Nov/24.

I followed Koji's calibration formula (#6009) to get the actual peak value (half of the peak-peak value) of the RF outputs and then divided them by the DC output to make them RIN.

It looks the RINs are hovering at ~ 4 x 10-4 and fluctuate from 1x10-4 to 1x10-3. Those numbers agree with what we saw before (#5616)

So it seems the StochMon is working fine.

Quote from #6009

 New RFAM mon calibration

  6064   Sat Dec 3 16:55:52 2011 DenUpdateIOOdigital noise in MC

I looked once again to the local OSEM sensors and MC length signals. Then I replaced 1e-20 to 1e-50 in the if-statement of the iir_filter function. Here I report about the difference of the signals in question.

First we look at the MC2 OSEM local sensor. In the figure below the psd of the signal is presented in three cases - with a free MC2 mirror without feedback, with a feedback signal and with a feedback signal with corrected if-statement. We can see that without FB the wire resonances are high and dumped when OSEMs are on. However we can see that below 1 Hz the psd of the sensor signal with 1e-20 in the if-statement is higher then psd of the sensor signal from free mirror. FB with 1-50 in the if-statement fixes this problem. 

psd_sensors.jpg

If we take a look on the plot of the coherence between GUR1_X and SENSOR signals we can see that coherence is corrupted when 1e-20 is used in the is-statement and is good when 1e-50 is used.

coh_sensors.jpg

 Next we look at the psd of the MC length. We can see how strongly these curves diverge below 1 Hz. The MC_F signal was also corrupted at higher frequencies.

psd_mcl.jpg

 The coherence between MC_F and GUR1_X is also improved.

coh_mcl.jpg

  6066   Sun Dec 4 13:56:54 2011 DenUpdateIOOWFS

Yesterday I locked the MC and left at 8 pm. Analyzing the data I saw that MC was locked all time from 8 pm to 12.30 am when it lost lock. Moreover there was no light on transmition and reflected screens at all. I went to the PSL and saw that no red light comes to the MC from PSL, only green. I took infrared sensos to track the laser light. Then I came back to control room to study the medm diagram of the PSL. Then I came back and saw that the laser beam goes to the MC! I returned to control room and saw light on the MC screens. Does someone do something parallel with me through ssh?

I enabled the auto locker and saw the MC locked for a couple of seconds. After that the WFS were turned on automatically and I saw that the signal of the OSEM local sensors of the MC mirrors began to increase. So the WFS master provides not good feedback signal. I thought that it is due to my recompilation of c1mcs with a fixed if-statement line. And may be if c1mcs workes without digital noise and c1ioo with it then there might occur some mismatches and the signal is corrupted. For this assumption I've recompiled c1mcs back to 1e-20 in the if-statement and so added the digital noise back that I saw in the dtt tools.

However, the problem was still present - WFS feedback signal crashed the MC lock. I open the WFS master window and disabled the output to MC. I can see that the C1:IOO-WFS1_PIT_INMON and other input channels have reasonable values 8 - 20 but the output continues to increase up to 1000000. The output was off so the MC stayed at lock. As for now I turned off WFS so no feedback is applied to MC mirros.

  6067   Sun Dec 4 23:49:38 2011 DenUpdateIOOWFS

Quote:

Yesterday I locked the MC and left at 8 pm. Analyzing the data I saw that MC was locked all time from 8 pm to 12.30 am when it lost lock. Moreover there was no light on transmition and reflected screens at all. I went to the PSL and saw that no red light comes to the MC from PSL, only green. I took infrared sensos to track the laser light. Then I came back to control room to study the medm diagram of the PSL. Then I came back and saw that the laser beam goes to the MC! I returned to control room and saw light on the MC screens. Does someone do something parallel with me through ssh?

I enabled the auto locker and saw the MC locked for a couple of seconds. After that the WFS were turned on automatically and I saw that the signal of the OSEM local sensors of the MC mirrors began to increase. So the WFS master provides not good feedback signal. I thought that it is due to my recompilation of c1mcs with a fixed if-statement line. And may be if c1mcs workes without digital noise and c1ioo with it then there might occur some mismatches and the signal is corrupted. For this assumption I've recompiled c1mcs back to 1e-20 in the if-statement and so added the digital noise back that I saw in the dtt tools.

However, the problem was still present - WFS feedback signal crashed the MC lock. I open the WFS master window and disabled the output to MC. I can see that the C1:IOO-WFS1_PIT_INMON and other input channels have reasonable values 8 - 20 but the output continues to increase up to 1000000. The output was off so the MC stayed at lock. As for now I turned off WFS so no feedback is applied to MC mirros.

With the help of Suresh we have adjusted optics near PMC and input to the MC on the PSL and in the black box where WFS are. Surprisingly, some optics near WFS was not attached to the table. But these mirrors are not used. One screw was near the hole but not screwed in. This mirror is used. Suresh could also rotate other screws. I thought that they must be attached to the table more rigidly.

Then we found that WFS output matrix is wrong and Suresh recalculated it. After that we've locked the MC using WFS. C1:IOO-MC_RFPD_DCMON is 0.7-0.8. 

We also recompiled and reinstalled C1MCS and C1IOO with fixed if-statement and again saw how MC_F curve moves down. WFS error signals are also improved. But still some more work on output matrix is needed.

  6084   Thu Dec 8 00:04:50 2011 ranaUpdateIOORAM Mon is now being demodulated

Monitoring good, but remember that the EOM alignment must be done carefully to minimize the RAM before we can use these trends.

  6089   Thu Dec 8 14:47:28 2011 JenneUpdateIOOEOM aligned to minimize RAM

Quote:

Monitoring good, but remember that the EOM alignment must be done carefully to minimize the RAM before we can use these trends.

 I temporarily diverted the output of the RAMmon PD to a spectrum analyzer (4195 in Spectrum Analyzer mode), and tweaked the EOM alignment until I minimized the 11 and 55 MHz peaks as much as possible.  It was possible to get each individual peak to disappear into the noise (about -70dBm), but to get both minimized simultaneously I wasn't able to get both down into the noise.  I left the 11MHz at about -55dBm, and the 55MHz at about -60dBm.  If Kiwamu's simulation tells us that one is more significant than the other (55, because we use it for MICH?), then we can decide to favor putting that peak in the noise and sacrifice ~10dB in the other peak. 

When I first plugged the PD into the analyzer, I saw 22MHz and 44MHz (small) peaks, but they went away after the first bit of tweaking.

Before having used the analyzer, I was trying to minimize the demodulated signals via StripTool, but that was a slow process.  The spectrum analyzer was obviously much faster.

The PD has been returned to the regular RAMmon electronics.

Next up: putting in the new demod box that Koji tested last night.

  6096   Fri Dec 9 15:49:24 2011 JenneUpdateIOOMC trans is way down

I was looking at the trends from the RAMmon, since I did the EOM alignment yesterday, and wanted to compare them to the MC trans, just to make sure the MC was locked during the times I'm examining.  I was dismayed to discover that the MC has lost its oomph, starting around 11:30 this morning.  Den was the only person in the lab to my knowledge at that time, and he claims that he didn't touch the MC until well after lunch.  As you can see from the 8 hour trend attached, we went from normal ~26000 counts to ~15000, and we're slowly decaying from there.

MC refl looks pretty bad on the camera, particularly in YAW.  Investigations are beginning now....

Edit, ~10min later...  I enabled the WFS (I don't know why they were off...when the MC fell out of lock and relocked itself, the WFS didn't come on), and things went basically back to how they should be.  However, the sans-WFS alignment is still totally crappy, so the PSL beam probably needs to be aligned to the MC.  I don't really want to touch the alignment though without an okay from Kiwamu, so I'll wait for him to come in and confirm that he's happy with the current MC.

  6098   Fri Dec 9 17:15:29 2011 JenneUpdateIOOMC trans is way down

Quote:

I was looking at the trends from the RAMmon, since I did the EOM alignment yesterday, and wanted to compare them to the MC trans, just to make sure the MC was locked during the times I'm examining.  I was dismayed to discover that the MC has lost its oomph, starting around 11:30 this morning.  Den was the only person in the lab to my knowledge at that time, and he claims that he didn't touch the MC until well after lunch.  As you can see from the 8 hour trend attached, we went from normal ~26000 counts to ~15000, and we're slowly decaying from there.

MC refl looks pretty bad on the camera, particularly in YAW.  Investigations are beginning now....

Edit, ~10min later...  I enabled the WFS (I don't know why they were off...when the MC fell out of lock and relocked itself, the WFS didn't come on), and things went basically back to how they should be.  However, the sans-WFS alignment is still totally crappy, so the PSL beam probably needs to be aligned to the MC.  I don't really want to touch the alignment though without an okay from Kiwamu, so I'll wait for him to come in and confirm that he's happy with the current MC.

 Kiwamu and I discussed, and looking at the AS camera with the PRM and SRM misaligned, but MCWFS engaged, things look good.  This means that it's probably the MC that has drifted, and we want to align the MC back to the PSL beam.

  6113   Tue Dec 13 16:31:40 2011 ZachUpdateIOOPSL beam realigned into MC

The MC coupling had become re-shittified. As we need transmitted MC light for the RAMmon, I realigned the input beam to the MC. (Jenne said that the MC mode itself should be well aligned, so I just used the zigzag on the PSL). MC_REFL is now ~0.5-0.6.

  6114   Tue Dec 13 18:56:23 2011 ranaUpdateIOOPSL beam realigned into MC

 

 Of course, looking at the MC transmission os the important thing, but I wonder if maybe we should also monitor the beam before it goes into the MC just to see if its the fault of the MC-WFS or not. In the bad old MZ days, I remember that the MC mirror alignment would drastically change the post-MC RAM.

It requires another PD/demod set, but may be illuminating in the end. 

Also, can someone please add some channels to EPICS which calibrate the RAM channels into RAM units?

  6115   Wed Dec 14 01:35:06 2011 KojiUpdateIOOMC alignment craziness

~11PM I came to the 40m and found the MC is repeating "LOCK->WFS ON->UNLOCK" sequence for ~2hours.

I checked the WFS spots on the QPDs and aligned them. No luck. I suspected the clipping of the beam in the chamber.

After I checked the trends of MC SUS OSEM values and IPPOS, I concluded that the input beam was aligned to somewhat misaligned MC.

The most noticable thing was that IPPOS (X, Y) indicated about (-0.5, 0) although the recent trend shows (-1, -0.5) is nominal.
In fact, the beam was about dropping from the diode. In addition, I found that the MC2 suspension showed a jump in the morning at around 8.30AM.|
This is consistent with what Jenne described.

This was a difficult situation as everything was moved.
I used the OSEM values to come back to the previous alignment of the suspensions, and started touching Zig-Zag before the MC.
After the alignment I ended up more clipping of the MC REFL. Also the spot on the IPPOS QPD was more dropping.

So, I have empirically used MC3 to misalign in Yaw to have better spot position on IPPOS. Then, the Zig Zag was aligned.
Then the spot on MC2 was adjusted while MCTRANS was kept maximized.

This helped the things back in the normal state.

Now the WFS servo is happily controlling the alignment.
MC REFL is 4.8 and 0.47 for unlocked and locked. (MCREFL_UNLOCK was 4.6 before my touch)
MCTRANS is 27000, which is close to the nominal.
IPPOS total, x, and y are 0.36, -0.97, and -0.47, respectively. They are about the nominal.

~1AM done

HOWEVER, we still don't know the position of the spot on MC1/MC3, and ITMY and ETMY.
I should consult with Kiwamu to check the spot positions tomorrow.

General lessons:
- If you find any reduction of MC transmission, check the suspensions to see if there is any slip.
- Before touching the input optics to recover the MC alignment, we should think what was moved.
- Before touching EOM alignment you must check the MC alignment WITHOUT WFS, so that you can recover the misalignment of EOM by the Zig-Zag steering.
- WFS is sensitive to clipping of the beam.
- We need a nifty indicator to tell how the MC transmitted beam is good.

  6118   Wed Dec 14 14:07:48 2011 KojiUpdateIOOMC alignment craziness

[Kiwamu Koji]

To check if the MC alignment is OK or not, we tried to lock the Y-arm.

Once the alignment of Y-arm was restored, we saw the resonant peak of ~0.2 in TRY.
After a small tweak of PZT2, TRY has got improved up to 0.7.

Kiwamu made a small tweak on the problematic PZT1, then the full (1.0) TRY was recovered.

Thus we concluded the current MC alignment is good enough.

  6146   Thu Dec 22 20:49:33 2011 KojiUpdateIOOLimitter activated for WFS servos

I set the limitters of the MC WFS servos not to inject the feedback more than 2000.

The residual of the WFS shakes the MC SUSs at every lock loss.

  6164   Wed Jan 4 00:43:06 2012 kiwamuUpdateIOOMC became flaky

I don't know what exactly is going on, but MC became flaky and it's been frequently unlocked.

I have turned off the MC WFS servo to check if the WFSs are doing something bad. But it still tends to be unlocked without the WFS servo.

Right now it doesn't stay locked for more than 10 min.

  6198   Sat Jan 14 00:50:08 2012 rana, kojiConfigurationIOOTowards coating thermal noise measurement with RefCav / MC beat

Koji asked aloud tonight if we could measure the coating thermal noise of the refcav optics by beating the refcav light with the MC_TRANS light. Then we looked at our calculations for the noises:

Displacement noise of T=200ppm silica/tantala coating on a 1" silica substrate with a 300 micron beam spot = 1e-18 * sqrt(100 Hz / f) m/rHz.

Displacement noise from coating thermal in the MC is roughly smaller by the beam size ratio (1.8 mm / 0.3 mm). Some differences due to 3 mirrors and more layers on MC2 than the others, but those are small factors.

So, the frequency noise from the refcav should by larger than the MC thermal noise by a total factor of (1.8 / 0.3) * (13 m / 8 inches) ~ 400.

Another way to say it is that the effective strain noise in the RC is (1e-18 / 0.200) = 5e-18 /rHz. This translates into (5e-18 * 13) = 6.5e-17 m/rHz in the MC. (in frequency noise its 1.5 mHz/rHz).

I have measured the frequency noise in the LLO MC to be at this level back in 2009, so it seems possible to use our RC + MC to measure coating thermal noise by the length amplification factor and compete with Frank+Tara.

 

So today we set up the Jenny RC temperature setup to lock the LWE NPRO to the RC and then set up the beat note with the IFO REFL beam on the AS table. By using the 2 laser beat, we are avoiding the VCO phase noise issue which used to limit the PSL frequency noise at ~0.01 Hz/rHz. To do this we have reworked some of the optics on the PSL and AS tables, but I think its been done without disturbing the beams for the regular locking. Beat note has been found, but the NPRO has still not been locked to the RC - next we setup the lockin amp, dither the PZT, and then use the New Focus lock box to lock it to the RC.

You might think that its hard to measure this since the MC has ~1 MHz frequency fluctuations and we want to measure down to 1e-4 Hz. But, in fact, we can just use a 200 m MFD with a LT1128 preamp. Then we use the MFD to stabilize the MC length to the refcav and just use the control + error signal of the MFD setup as the coating thermal noise measurement.

 

Note: Beat found at ~40deg for the aux laser. The aux laser is on but the shutter is closed.
The AS camera seems to be hosed. Need a bit of alignment. (KA) ==> Fixed. (Jan 15)

  6205   Tue Jan 17 03:10:27 2012 kiwamuConfigurationIOOrotated lambda/2 plate

I have slightly rotated the lambda/2 plate, which is used for attenuating the REFL beam's power on the AS table

because the plate had been at an unusual angle for investigation of the glitches since last Thursday.

It means the laser power going to the coating thermal noise setup has also changed. Just keep it in mind.

Quote from #6198

So today we set up the Jenny RC temperature setup to lock the LWE NPRO to the RC and then set up the beat note with the IFO REFL beam on the AS table. By using the 2 laser beat, we are avoiding the VCO phase noise issue which used to limit the PSL frequency noise at ~0.01 Hz/rHz. To do this we have reworked some of the optics on the PSL and AS tables, but I think its been done without disturbing the beams for the regular locking. Beat note has been found, but the NPRO has still not been locked to the RC - next we setup the lockin amp, dither the PZT, and then use the New Focus lock box to lock it to the RC.

  6213   Thu Jan 19 23:34:52 2012 kiwamuUpdateIOOPMC realignment and HEPA

I realigned the incident beam to PMC at 23:30. The transmitted light went up from 0.78 to 0.83.

Also I decreased the HEPA level down to 20 % for the night time locking.

  6217   Mon Jan 23 15:43:47 2012 JenneUpdateIOOPMC realignment

Quote:

I realigned the incident beam to PMC at 23:30. The transmitted light went up from 0.78 to 0.83.

 Do we have PSL pos and ang QPD trends?  We should start watching them, because the PMC drifted back down to 0.76 transmission, ~3.5 days after Kiwamu realigned it (his elog is from last Thurs).  Not so awesome.

I walked through the control room just now and found both PMC and MC unlocked.  They're both locked now, but with PMC transmission 0.76, MC transmission ~24,500.

  6218   Mon Jan 23 23:12:00 2012 kiwamuUpdateIOOPMC realignment

I have realigned the beam pointing to PMC. The transmitted light increased from 0.74 to 0.83.

The misalignment was mainly in pitch.

  6228   Thu Jan 26 15:35:23 2012 JenneUpdateIOOMC ~1Hz badness

The mode cleaner is super unhappy.  It's rocking around at ~1Hz.

I turned off the WFS and turned them back on after the MC was locked, and it seems a little happier now.  At least it's not falling out of lock ~1/minute.

  6229   Thu Jan 26 19:28:02 2012 kiwamuUpdateIOOPMC low transmission

After I recovered the lock of PMC, I found that the PMC transmission was quite low. It was about 0.26 in the EPICS display.

I zeroed the PSL temperature feedback value which had been -2.3 and then the PMC transmission went back to a normal value of 0.83.

I believe it was because the PSL was running with two different oscillation modes due to the big temperature offset.

  6236   Mon Jan 30 08:17:06 2012 steveUpdateIOOPMC

Quote:

I have realigned the beam pointing to PMC. The transmitted light increased from 0.74 to 0.83.

The misalignment was mainly in pitch.

 The PMC pointing has changed, so MC is resonating in high order modes.

  6239   Tue Jan 31 08:44:10 2012 steveUpdateIOOlaser shuts down

 

 The 2W Innilight shutdown shut when I opened side door for safety scan. This was not a repeatable by opening -closing side doors later on. Turned laser on, locked PMC and MC locked instantly. The MC was not locked this moring and it seemed that the MC2 spot was still some high order mode

like yesterday. MC lock was lost when the janitor bumped something around the MC.

  6240   Tue Jan 31 14:58:30 2012 kiwamuUpdateIOOlaser shuts down

[Steve/ Kiwamu]

 We found that the laser had completely shut off for ~ 4 hours even with all the PSL doors closed.

We are guessing it is related to the interlock system and Steve is working on it to fix it.

Quote from #6239

 The 2W Innilight shutdown shut when I opened side door for safety scan. This was not a repeatable by opening -closing side doors later on. Turned laser on, locked PMC and MC locked instantly. The MC was not locked this moring and it seemed that the MC2 spot was still some high order mode

like yesterday. MC lock was lost when the janitor bumped something around the MC.

 

  6241   Tue Jan 31 17:13:49 2012 steveUpdateIOOonly the PSL laser is off

 

The 2W PSL laser is turned off.  The danger laser lights are not illuminated at the entry doors because of malfunctioning electronic circuit!!!

Laser safety glasses are still required!  Other lasers are in operation!

  6242   Wed Feb 1 17:00:57 2012 steveUpdateIOOlaser is back ON

Quote:

 

The 2W PSL laser is turned off.  The danger laser lights are not illuminated at the entry doors because of malfunctioning electronic circuit!!!

Laser safety glasses are still required!  Other lasers are in operation!

 BEN fixed the interlock.  The laser is turned ON. Thanks for all, Rich and Sam who came over to help. Atm1

All emergency shut- off switches, lights and door indicators are working at this moment. More about this tomorrow.

Atm2, PSL enclosure interlock jungle without REAL schematic drawing.....at this point.... We all agreed it is easier to redo the hole thing than find the problem

Atm3, Emergency shut off switches and illuminated signs from  entry doors to AC on-off box  ( Use this switches in emergency ONLY,  otherwise leave alone , even it is labeled obsolete !)

Summery: I still do not really know what was wrong.

 

  6244   Fri Feb 3 14:44:33 2012 JenneUpdateIOOMC SUS misalignment

The mode cleaner is a little misaligned in pitch, and is very misaligned in yaw.  The lowest order mode that is flashing is TEM11.

I had a look-see at the SUS sensors, to see if there were any big jumps.  There were moderately sized jumps on all 3 mode cleaner optics.

SUSjump_3Feb2012.png

The MC's lockloss was at ~8:22am this morning, and went along with a giganto kick to the optics.  Steve tells me that Den might have been kicking up optics while doing computer things this morning, before Steve reminded him to shut off the watchdogs.  However, Steve was also taking phots/measuring things near MC Refl, so maybe he's not totally absolved of blame.  But this really looks like the optics settled to different places after big kicks.

I'm going to try to align the MC mirrors to get back to the sensor numbers from early this morning before chaos began.

Reminder / Moral:  Everything cannot be considered to be "working fine" if the MC isn't locking.  See if you can figure out why, and especially if it's something that you screwed up, either fix it, or better yet, ask for help and learn how to fix what you broke.

  6246   Fri Feb 3 15:49:10 2012 JenneUpdateIOOMC SUS misalignment

[Jenne, Den]

We moved the MC approximately back to where the sensors for each optic used to be (mostly touching MC2, but a little bit of MC1 to help the refl get back to its max value).  MC is now locked, and with the help of the WFS it's back to nominal.  I forgot to disable the WFS, so I think we aren't perfectly aligned, but we're close enough for the WFS to get us the rest of the way.  We're heading over to JClub right now, so we're going to leave it as-is.

  6248   Fri Feb 3 17:17:47 2012 DenUpdateIOOMC SUS misalignment

Quote:

Reminder / Moral:  Everything cannot be considered to be "working fine" if the MC isn't locking.  See if you can figure out why, and especially if it's something that you screwed up, either fix it, or better yet, ask for help and learn how to fix what you broke.

When I left this morning, Steve was still working with the MC and it was unlocked anyway, I could not check it. By "fine" I meant only watchdogs. The thing is that before starting to work with c1lsc I turned off all the coils. Crazyness that Steve saw was after I turned them on back after reboot. This is a confusing thing - restarting models on c1lsc and burt restoring them is not enough. After I did it, everything at the STATUS MEDM screen was green, but the C1:SUS-???_??PD_VAR values went up after turning on coils. So sus and lsc communicated in a bad manner after the reboot. After restarting x02 model, the watchdogs were fine again.

  6251   Fri Feb 3 19:54:21 2012 ranaConfigurationIOOMC trans awry

As usual, I noticed several bad things within 30 seconds of sitting in front of the workstation. Today its that there are OFF or missing filters on the MC TRANS.

is this the normal state? Screenshot attached.

  6262   Thu Feb 9 13:04:11 2012 KojiSummaryIOOPMC/IMC alignment

There has been no lock of input MC for more than 5days. WTF???

I have fixed a loose mirror of the PMC input and the alignment of the MC2 Yaw.


- The PSL mech-shutter was closed. It has been opened.

- Then, I checked the MC suspensions. Mainly MC2 Yaw has kept drifting. (Fig.1)
In fact, there was no WFS actions during this drift.

Anyway, now MC2 Yaw was aligned and the lock was restored.

- It was very unsatisfactory for me that the PMC alignment kept drifting.
The trend of the PMC REFL and PMC TRANS for a year suggests that:

  • Occasional drifts exist since a year ago (or probably since we built this new PMC setup in 2010 Sep)
  • The drift has got frequent for the recent four months, and got more for the recent one month.

I went into the PMC setup and tapped several optics in order to find any loose optic.
Immediately I found that the mirror before the AOM was loose. Basically any mild tapping was enough
to misalign the mirror such that the caivty loose the TEM00 mode.

I tightened the retainer set screw of the optic and aligned the PMC again. It looks OK now as I can not
misalign this optic by the tapping anymore. But if it still remains drifting, we need to replace the mount.

  6266   Fri Feb 10 02:35:29 2012 kiwamuUpdateIOOcrazy ground motion

I gave up tonight's locking activity because the MC can't stay locked.

It seems that somehow the seismic noise became louder from about 1:00 AM.

I walked around the outside of the 40-m building to see what's going on, but no one was jumping or partying.

I am leaving the MC autolocker disabled so that the laser won't be driven crazy and the WFS won't kick the MC suspensions.

 

The attachment is a 3-hour trend of the seismometer outputs and the MC trans.

MCunlock.png

  6268   Fri Feb 10 11:01:31 2012 steveUpdateIOOcrazy ground motion

Quote:

I gave up tonight's locking activity because the MC can't stay locked.

It seems that somehow the seismic noise became louder from about 1:00 AM.

I walked around the outside of the 40-m building to see what's going on, but no one was jumping or partying.

I am leaving the MC autolocker disabled so that the laser won't be driven crazy and the WFS won't kick the MC suspensions.

 

The attachment is a 3-hour trend of the seismometer outputs and the MC trans.

MCunlock.png

 Something has started shaking last night.  Everybody is claiming to be innocent next door.

I turned off the 40m AC at 11:06

  6269   Fri Feb 10 11:46:44 2012 steveUpdateIOOseismic noise back to normal

The shaking has stopped at 9:32am  The AC was turned back on at 11:30am  We still do not have any explanation

 

  6274   Fri Feb 10 23:19:09 2012 kiwamuUpdateIOOcross talk causing fake seimometer signals

[ Koji / Kiwamu ]

The frequent unlock of the MC are most likely unrelated to ground motion.

Although the reason why MC became unstable is still unclear.

 

 

There are two facts which suggest that the ground motion and the MC unlock are unrelated :

(1) It turned out that the seismometer signals (C1:PEM-SEIS-STS_AAA ) have a big cross talk with the MC locking signals.

    For example, when we intentionally unlocked the MC, the seismometer simultaneously showed a step-shaped signals, which looked quite similar to what we have observed.

    I guess there could be some kind of electrical cross talk happening between some MC locking signals and the seismometer channels.

    So we should not trust the signals from the STS seismometers. This needs a further investigation.

(2) We looked at the OSEM and oplev signals of some other suspended optics, and didn't find any corresponding fluctuations.

    The suspensions we checked are ETMX, ETMY, ITMX and MC1.

     None of them showed an obvious sign of the active ground motions in the past 24 hours or so.

Quote from #6266

It seems that somehow the seismic noise became louder from about 1:00 AM.

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