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ID Date Author Type Categoryup Subject
  5939   Fri Nov 18 01:27:04 2011 DenUpdateIOOMC locked

[Mirko, Den]

While the MC was unlocked (and the local damping off) we've measured the coherence between GUR1_X and OSEM sensors. It was rather high, close to 1 at frequencies 0.1 - 1 Hz. That means that stack does not kill all coherence between seismic noise and mirror motion.

Then we've turned on the local damping and measured the coherence again between GUR1_X and OSEM sensors. It decreased due to some noise and was on the level of ~0.5. We did reduced the motion between the mirror and the frame by local damping but it is not obvious that we lost some coherence due to this effect. Probably, actuator adds some noise.

When we locked the MC, we did not see any coherence at 0.1 - 1 Hz between GUR1_X or STS1_X and OSEM sensors of MC1 and MC3 but we did see with MC2. The MC1 sensor was fixed by Suresh.

 

Attachment 1: cohnolocalpumping-crop_4.pdf
cohnolocalpumping-crop_4.pdf
Attachment 2: cohlocalpumping4-crop.pdf
cohlocalpumping4-crop.pdf
Attachment 3: cohlock4-crop.pdf
cohlock4-crop.pdf
  5941   Fri Nov 18 01:51:37 2011 KojiUpdateIOOStochmon update

Update of the stochmon status

[Attachment 1: Circuit diagram]

- The new stochmon has a low noise amplifier (MAR-6SM) inside.
The RFAM signal from the PD has the power of -60~-50dBm, which is almost at the bottom of the sensitivity for the power detector.

- The band pass filters were doubled.

- I've suffered from some RF coupling from the power line as the power detector is quite sensitive to it.
The situation has been largely improved by the EMI filters in the power supply path, although the problem is still present.
The worst remaining problem is that we can not close the aluminum lid as it cause a huge sprious coupling.

 

[Attachment 2: Calibration result]

- The outputs were calibarted with Marconi. They showed the signals linear to dBm for the input powers between -70dBm and -10dBm.

- The calibration result was fitted with the empirical fit function. The function and the results are shown in the attachment.

[Attachment 3: Detection limit]

- The attached figure shows the power spectrum of the PD output. This measurement gives us the amount of the RF power given from the PD noise when there is no RF signal.

11MHz out passband noise: −72.7dBm ===> V11 = 2.0483
30MHz out passband noise: −64.6dBm ===> V30 = 1.9333
55MHz out passband noise: −71.2dBm ===> V55 = 2.0272

- Now 11MHz and 55MHz outputs seem indicating the power correctly, but the 29.5MHz output never provides useful information.
It is a constant value independent from the state of the incident beam. Strangely this problem disappears if the marconi is used
for the RF source. Thus this issue is not seen in the calibration measurement.

- So far, 11MHz, 29.5MHz, 55MHz, and DC outputs appear in the channels C1:IOO-RFAMPD_33MHZ, C1:IOO-RFAMPD_133MHZ, C1:IOO-RFAMPD_166MHZ, and C1:IOO-RFAMPD_199MHZ.
They will be renamed.

Attachment 1: stochmon.pdf
stochmon.pdf
Attachment 2: stochmon_calib.pdf
stochmon_calib.pdf
Attachment 3: RFAM_PD_noise.pdf
RFAM_PD_noise.pdf
  5942   Fri Nov 18 02:50:10 2011 kiwamuUpdateIOORF generation box : power switch malfunction

[Suresh / Kiwamu]

 The power switch button of the RF generation box is not properly working

For tonight we are leaving it as it is but it needs to be fixed at some point.

 

(the Story)

While I was working around the green broad-band RFPD, I noticed that the RFPD was detecting the 25 MHz modulation signal.
To confirm if it really comes from the modulation source, I switched OFF the RF generation box by pressing the blue LED power button on the rear side of it.
The 25 MHz signal in the RFPD disappeared. So it was indeed the 25 MHz modulation signal.
Then I pressed the LED button again to bring it ON, but the switch didn't stay in the clicked position.
Keeping pressing the button could make it ON but once I released my finger from it it became OFF.
So the mechanical thing in the LED button is not properly working.
I removed the box from the 1X2 rack to take a look at it.
With a help from Suresh we somehow managed to keep it ON after several trials of pressing it.

The temporary solution we decided is to leave it ON so that we can survive tonight.

The box was back in place. The MC is find and 11 MHz and 55 MHz seem okay.

 

Please be aware of it.

 

broken_power_switch.png

This is a picture showing the rear view of the RF generation box. The red arrow is pointing the blue LED switch button.

  5943   Fri Nov 18 08:29:35 2011 SureshUpdateIOOHEPA air-flow effect on WFS.

[Koji, Suresh]

    We investigated the effect of airflow from the HEPA filters on the PSL beam fluctuation and the resultant noise injected into the WFS loops.   The hint that the WFS are injecting PSL beam jitter into MC mirror motion lies in the MC2_TRANS_PIT and YAW signal's power spectrum shown here.  First, in the blue trace, which shows the spectrum when the WFS loops are off, we see that the WFS1 and WFS2 error signals have a different shape from that of MC2_TRANS.  Since WFS are affected by the PSL beam jitter while the MC2_TRANS_QPD is not, the WFS spectrum contain excess noise, while the MC2_TRANS signals show only the mirror motion.  Next, upon switching on the WFS1 and WFS2 loops, we notice that the MC2_TRANS  spectra acquire the same shape as the WFS spectra.  This shows that the excess noise from the beam jitter has been injected into the MC2 motion, and shows up in the MC2_TRANS spectra.

   To confirm these conclusions we repeated the above measurement with the HEPA fans at 0% (Blue trace), 20% (Red), 30% (Brown) and  100% (Green).   The plots are shown below.  We can see that there is no difference between 0 and 20% levels but beam jitter is visible at 30% HEPA level.  The WFS loops were ON during this time and we can can see the PSL noise injected in to MC2 motion (Green).

WFS_err_HEPA.png

 

The HEPA filter fans are now at 20%.  How can we be sure that they are really working at 20%, since we cannot see any difference between 0 and 20%?

Now that we have this quiet situation, we also investigated the effect (or lack thereof) of switching on the MC2_TRANS loops.  The figure below shows the spectra with all the loops turned off (Blue), with the WFS1 and WFS2  loops turned on (Green)  and with everything turned on (Red).   With the current output matrix, which is the same simple one as the one in this elog, we see some low frequency suppression.  But it also seems to add some noise into the other WFS loops.  I am not sure of this result, due the long duration of this measurement, the seimic noise level may have changed over the course of this measurement.

WFS_err_mc2t_effect.png

As they are not doing any good just now.  I have turned them off by setting the gain in MC2_TRANS PIT and YAW to zero.

 

  5944   Fri Nov 18 11:16:08 2011 ranaUpdateIOOeom box

Quote:

I made a super sweet new foam box for our EOM.  It's awesome, and should be reasonably easy to duplicate.  Check out the PHOTOS!

 These are great photos and a nice box, but I fear from the photos that there's too much air getting in. How to pack it so that there's no air flow? How does the temperature sensors wires get in?

  5947   Fri Nov 18 15:35:18 2011 kiwamuUpdateIOORF generation box : power switch malfunction

Jenne gave me a spare LED power switch .

I will replace the broken one on Monday.

By the way here is a picture album of the RF generation box which I took last night.

            

Quote from #5942

 The power switch button of the RF generation box is not properly working

  5949   Fri Nov 18 15:45:11 2011 MirkoUpdateIOOMode cleaner noise projection

[Rana, Den, Mirko]

Updated the MC noise projection to include the longitudinal motion of the MC mirrors.

WholeMCNoiseProjection.png

=> Lots of OSEM - local dampling noise!

Consistent with static wiener filter showing only benefits in the 1 - 4Hz region.

Attachment 2: WholeMCNoiseProjection.fig
  5952   Fri Nov 18 19:57:19 2011 MirkoUpdateIOOMode cleaner noise projection

 

Some more info on this:
 

f > 1 Hz:

At these frequencies the pendulum should be quieter than the stacks. By quite a bit actually since there is the stack resonance at a couple Hz. 'Glueing' them together via the local control is not wise. We put an elliptic LP ( 2.5Hz, 4th order 6dB) into the C1:SUS-MC?_SUSPOS pathes and MC-F got better above 1Hz

MC_ELP.png

Added an extra LP @ 10 Hz afterwards. Doesn't make a visible difference.

f < 1 Hz:

Now here is more stuff to consider.

1. The OSEMs glue the MC mirrors to the stacks
2. The pendulum TF should be 1
3. It shouldn't matter if the OSEMs do or do not act on the mirror at these frequencies, assuming they don't add extra noise.
4. Page http://nodus.ligo.caltech.edu:8080/40m/5547 seems to indicate OSEM sensor noise is so low it can be neglected.

Reduced OSEM gain below 1Hz:

If we reduce the gain in the OSEMs by adding additional HP filters ( cheby2, HP 0.3Hz, 6dB 4th order ) the happens:

1. MC length gets a bit more noisy at low frequencies - should be looked into some more
2. Coherence between the GUR1 seismometer and MC length goes up between 1E-2 and 1E-1 Hz:

( Ref is with low OSEM gain )

WithAndWithoutHPs.pdf

Possible explanation:

The stacks might be more correlatedly moving together than the pendulums. This would be not so nice for OAF test, but really fine for actually using the MC.
Todo: Measure the OSEM to seismometer coherences with high and low OSEM gains.

For reference the seismometer coherence with one another:
SeismCoh.pdf

 

 

  5953   Fri Nov 18 23:44:33 2011 ranaUpdateIOOMode cleaner noise projection

Could use some more detail on how this measurement was done. It looks like you used the SUSPOS signal with the mirror moving, however, this is not what we want. Of course, the SUSPOS with the mirror moving will always show the mirror motion because the OSEMs are motion sensors.

Instead, what we want is to project how the actual OSEM noise in the presence of no signal shows up as MC length. For that we should use the old traces of the OSEM noise with no magnets and then inject that spectrum of noise into the SUSPOS filter bank with all the loops running. We can then use this TF to estimate the projection of OSEM noise into the MC length.

As far as improving the damping filter, the 2.5 LP is not so hot since it doesn't help at low frequencies. Instead, one can compute the optimal filter for the SUSPOS feedback given the correct cost function. To first order this turns out to be the usual velocity damping filter but with a resonant gain at the pendulum resonance. This allows us to maintain the same gain at the pendulum mode but ~3x lower gain at other frequencies.

In the past, we had some issues with this due to finite cross-coupling with the angular loops. It would be interesting to see if we can use the optimal damping feedback now that the SUS DOFs have been diagonalized with the new procedure.

  5957   Sat Nov 19 01:26:16 2011 DenUpdateIOOMode cleaner noise projection

Quote:

Instead, what we want is to project how the actual OSEM noise in the presence of no signal shows up as MC length. For that we should use the old traces of the OSEM noise with no magnets and then inject that spectrum of noise into the SUSPOS filter bank with all the loops running. We can then use this TF to estimate the projection of OSEM noise into the MC length.

That's right. The easier problem arises if we consider one of  MC mirrors. The coherence between OSEM sensors and GUR1_X in free moving regime is equal to 0.9 at frequencies 0.1 - 1 Hz. But with local dumping coherence is 0.6. We have

Mirror -> Sensor -> Satellite Module -> Whitening -> ADC -> Computer -> DAC -> Dewhitening -> Satellite Module -> Actuator -> Mirror

Somewhere we produce noise that kills part of coherence. We can use this method with the injection of spectrum of noise into the SUSPOS filter bank only for one mirror and see how the coherence between OSEM sensor and GUR1_X will change. If the change is small, we deal with something else. It the coherence will change from 0.6 to ~0.4, than we have big OSEM noise.

It might be also the problem that the amplitude of COIL_OUT signal is ~25. If it is in counts we may have noise from DAC. 

  5958   Sat Nov 19 06:04:43 2011 SureshUpdateIOOMC_WFS Servo: The MC2_TRANS_PIT and YAW loops switched ON

Without adding significant amounts of noise to other WFS loops I have engaged the MC2_TRANS_PIT and YAW loops. 

After several attempts to measure the system response and computing the output matrix, none of which gave any useful results, I gave up on that and decided to find three orthogonal actuation vectors which enable us to close the loops.  So using the last good output matrix (below left side)  as a template, I rounded it off to the nearest set of orthogonal vectors and arrived at the following matrix (right side):

WFS_OUTMx_Lastgood.png        WFS_OUTMATRIX_20111118.png

 

I also decided that WFS1 and 2 need not drive MC2.  This is just to decouple the loops and minimise cross-talk.   This (albeit heuristic)  matrix seems to work pretty well and the real matrix is probably quite close to it.

I show below the suppressed error signals after tweaking the gains a bit.   The blue line is with no WFS, the green one with only WFS1 and 2 loops on, while the red is with all loops turned on.  The WFS1Yaw and MC2_Trans_pit loops might benefit from a more careful study to determine a better output matrix.

WFS_err_MC2T_on_OMx5_20111118.png

  5959   Sat Nov 19 10:41:30 2011 ranaUpdateIOOMC_WFS Servo: The MC2_TRANS_PIT and YAW loops switched ON

I'm quite sure that this is not good: since MC2 can produce a signal in WFS1 and WFS2, it cannot be removed in this way from the actuation without introducing a significant cross-coupling between the MC_TRANS and WFS loops.

Really need loop TFs measured and compared with the model.

The WFS noise model will also show that we need to have a much lower UGF in the MCT loop since that sensor is just a DC QPD: it can never have as good of a sensing noise as a good WFS. In the current case with no Whitening, this is even more so.

  5960   Sat Nov 19 12:57:55 2011 MirkoUpdateIOOMode cleaner noise projection

Quote:

Could use some more detail on how this measurement was done. It looks like you used the SUSPOS signal with the mirror moving, however, this is not what we want. Of course, the SUSPOS with the mirror moving will always show the mirror motion because the OSEMs are motion sensors.

Instead, what we want is to project how the actual OSEM noise in the presence of no signal shows up as MC length. For that we should use the old traces of the OSEM noise with no magnets and then inject that spectrum of noise into the SUSPOS filter bank with all the loops running. We can then use this TF to estimate the projection of OSEM noise into the MC length.

As far as improving the damping filter, the 2.5 LP is not so hot since it doesn't help at low frequencies. Instead, one can compute the optimal filter for the SUSPOS feedback given the correct cost function. To first order this turns out to be the usual velocity damping filter but with a resonant gain at the pendulum resonance. This allows us to maintain the same gain at the pendulum mode but ~3x lower gain at other frequencies.

In the past, we had some issues with this due to finite cross-coupling with the angular loops. It would be interesting to see if we can use the optimal damping feedback now that the SUS DOFs have been diagonalized with the new procedure.

 The measurement was done with the MC in lock and the OSEMS active.

1. I injected noise into MC1-3 SUSPOS_EXC at a level that domiated the SUSPOS output.
2. Then I calculated the coupling coefficients of the SUSPOS outputs to MC_F during the time the noise is injected.
3. Without noise injection I projected the SUSPOS outputs to MC_F by multiplying the coupling coefficients with the SUSPOS outputs.

All on 11-11-18. White noise inj. from 0.1Hz to 20Hz. Duration 4mins each.

DOF      Amplitude(counts)     Time(UTC)
MC1      200                           22:08
MC2      25                             22:25
MC3      25                             22:50

Some thoughts on this, bare with me:

As you say this does not show the dark / bright noise of the OSEMs. It shows the influence of the OSEMS output onto MC_F in normal operation of the MC. I would have expected that to be very low everywhere except at the pendulum resonance. Reason for that not to be true could either be the OSEMs having considerable gain off of the resonance, or noise intrinsic to the OSEMs knocking the mirrors around. Since we know the OSEM signal to MC_F TF we only need to compare the OSEM signal to OSEM noise to see the noise contribution to MC_F. We know from http://nodus.ligo.caltech.edu:8080/40m/5547 that the OSEM sensor bright noise is considerably below the OSEM signal above 0.1Hz in actual operation. We checked that the MC OSEM signals are above the noise in the reference above 0.1Hz by a factor 3-10.

We actually measured the cost function with the noise projection (valid to 10Hz). It's just the coupling coefficient, right?

CouplingMClengthsToMCF.pdf

 

Attachment 2: NpModeCleaner.pdf
NpModeCleaner.pdf NpModeCleaner.pdf NpModeCleaner.pdf NpModeCleaner.pdf NpModeCleaner.pdf NpModeCleaner.pdf NpModeCleaner.pdf NpModeCleaner.pdf
  5961   Sat Nov 19 15:58:04 2011 MirkoUpdateIOOSome more looks into OSEM noise

[Den, Mirko]

We looked some more into the the OSEM signals and their coherence to the seismometer signals.

We were able to verify that the coherence OSEM sensor <-> seismometer signal goes down with increasing the OSEM gain. This seems to indicate that the OSEM FB add noise to the distance mirror <-> frame. We injected some noise into the OSEMs to see how the coherence behaves.

MC2 SUSPOS, 0.1Hz - 0.8Hz, 3mins each

Inj. amplitude   Time(UTC) Note

-                     21:35          Free swinging
-                     21:42          Big LF OSEM gain
-                     21:48          Small LF OSEM gain
150                     21:56          -"-
300                     22:00          -"-
900                     22:05          -"-

Free swinging:

FreeSwinging.png

High OSEM gain:


LocalDampingOn.pdf

Low OSEM gain:

LowOsemGain.pdf

LowOsemGainInj150.pdf

Low_LF_OSEM_Gain_Inj300.fig

LowOsemGainInj900.pdf

 

We left the filters that lower the OSEM gain below 0.3Hz on.

Attachment 2: High_Osem_Gain.pdf
High_Osem_Gain.pdf
Attachment 4: Low_LF_OSEM_Gain.fig
  5964   Sun Nov 20 15:11:09 2011 kiwamuUpdateIOORFAM monitoring test

DO NOT CHANGE THE IFO ALIGNMENT UNTIL TOMORROW MORNING OR FURTHER NOTICE.

Plus, MC has to be kept locked with the WFS.

 

An RFAM measurement is ongoing

 

 Since the Stochmon turned out to be tricky to calibrate the outputs, Koji and I decided to monitor the RFAMs using REFL11 and REFL55 RFPDs while the beam is single-bounced from PRM.
This is, of course, not a permanent RFAM monitor, but at least it gives us a long-term continuous RFAM information for the first time.
Before the measurement I ran the offset zeroing scripts, therefore any offsets from electronics must be tiny in the acquired REFL signals.
The measurement has begun from approximately 3:00 pm.
 
 Also I found C1LSC.ini file again became default (no channels had been acquired).
So I replaced it with an archived ini file and then restarted fb.
  5966   Mon Nov 21 12:48:00 2011 JenneUpdateIOORFAM monitoring test

I don't think I touched/adjusted/whatever anything, but I did open the PSL table ~5-10min ago to measure the size of the Kiwamu-Box, so if the RFAM stuff looks funny for a few minutes, it was probably me.  Just FYI.

  5967   Mon Nov 21 14:15:25 2011 JenneUpdateIOORFAM monitoring test

Quote:

DO NOT CHANGE THE IFO ALIGNMENT UNTIL TOMORROW MORNING OR FURTHER NOTICE.

 [Mirko,  Jenne]

We're playing with the MC OAF, so we're actuating on MC2.  Again, FYI.

  5968   Mon Nov 21 14:35:28 2011 kiwamuUpdateIOORFAM monitoring test

REFL_RFAM.png

 This is a trend for a day long showing the REFL11/55 demod signals, REFLDC (corresponding to the MC transmitted power) and the PSL booth temperatire.

There are sudden jumps in the REFL55_I and REFL11_Q signals around 5:00 AM this morning, also at the same time the temperature suddenly went up.

But the quality of the signal turned out to be not so good because the fluctuation is still within 1 bit of the ADCs,

we have to try it again with a bigger gain in the analog whitening circuit.

Quote:

An RFAM measurement is ongoing

  5969   Mon Nov 21 15:47:58 2011 MirkoUpdateIOOOsem loop shape

[Jenne, Mirko]

To reiterate: We changed the OSEM loop shape for MC1-MC3. Below in black is the old loop shape, which simulated pendulum response in there. In red is the new loop shape.

OsemFilterShape.pdf

The differences are due to extra filter in C1:SUS-MC?_SUSPOS module 6,7,9

6: Elliptical LP @ 2.5Hz
7: Inverse Chebychev HP @0.3Hz
8: 1st order LP @ 10Hz

This has the potential to be unstable, but is not. At some point these filters should be tuned further.

  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

Attachment 1: stochmon_calib.pdf
stochmon_calib.pdf
  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.

 

Attachment 1: WFS_err_20111127.png
WFS_err_20111127.png
Attachment 2: cioo_20111127.png
cioo_20111127.png
  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.

Attachment 1: MCtrans_9Dec2011.png
MCtrans_9Dec2011.png
  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.

Attachment 1: Untitled.png
Untitled.png
  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.

ELOG V3.1.3-