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ID Date Authorup Type Category Subject
  5198   Thu Aug 11 18:30:40 2011 KojiUpdateSUSITMY OSEM adjustment

[Jamie, Koji]

ITMX OSEMs were adjusted so as to have the right DC numbers and the more uniform response to POS excitation.

It is waiting for the free-swinging test.

- ITMX was moved from its position to the north side of the table.

- The table was rebalanced.

- We found that the output of the LR OSEM has an excess noise compared with the other OSEMs.
We tried to swap the LR and SD OSEMs, but the SD OSEM (placed at the LR magnet) showed
the same excess noise at around 10-50Hz.

- We found that one of the EQ stops was touching the mirror. By removing this friction, all of the OSEMs
come to show similar power spectra. Good!

 - Then we started to use LOCKIN technique to measure the sensitivity of the OSEMs to the POS excitation.

Originally the response of the OSEMs was as follows
UL 3.4 UR 4.3 
LL 0    LR 2.5   

After the adjustment of the DC values, final values became as follows
UL 3.9 UR 4.4
LL 3.9  LR 3.2

- We decided to close the light door.

  5224   Sat Aug 13 19:08:01 2011 KojiSummarySUSTT Optimization Curves

What are the parameters you are using? As you have the drawings of the components, you can calculate the masses of the objects.

 

Reducing the ECD resonance from 10Hz->6Hz looks nice.

The resonant freq of the ECDs are not (fully) determined by the gravitational energy but have the contribution of the elastic energy of the wire.

Q1: How much is the res freq of the ECDs if the freq is completely determined by the grav energy? (i.e. the case of using much thinner wires)

Q2: How thin should the wires be?

  5226   Sat Aug 13 21:48:17 2011 KojiSummarySUSTT Optimization Curves

1) Drawing has the dimensions => You can calculate the volume => You can calculate the mass
Complicated structure can be ignored. We need a rough estimation.

2) Your restoring force can have two terms:
- one comes from the spring constant k
- the other from the gravity

 

  5336   Fri Sep 2 15:56:32 2011 KojiUpdateIOOtriple resonant box : ready to install

What are the reflected RF powers for those frequencies? 
Is the 29.5MHz more problem than the 55MHz, considering the required modulation depth?

 

  5431   Fri Sep 16 11:15:12 2011 KojiUpdateIOOPZT1 situation

[Koji Kiwamu]

- We have checked the situation of the broken Piezo Jenna PZT (called PZT1)

- Tested PZT1 by applying a dc voltage on the cables. Found that pitch and yaw reasonably moving and the motions are well separated each other.
  The pitch requires +20V to set the IPPOS spot on the QPD center.

- Made a high-voltage (actually middle voltage) amp to convert +/-10V EPICS control signal into -5 to +30V PZTout. It is working on the prototype board and will be put into the actual setup soon.


Details:

- The Piezo Jenna driver box has 4 modules. From the left-hand side, the HV module, Yaw controller, Pitch controller, and Ben abbot's connector converter.

- We checked the voltage on Ben's converter board. (Photo1)
  It turned out that the red cable is the one have the driving voltage while the others stays zero.

- We hooked a 30V DC power supply between the red cable and the shield which is actually connected to the board ground.

- Applying +/-10V, we confirmed the strain gauge is reacting. If we actuated the pitch cable, we only saw the pitch strain gauge reacted. Same situation for yaw too.

- Kiwamu went to IPPOS QPD to see the spot position, while I change the voltage. We found that applying +20V to the pitch cable aligns the spot on the QPD center.

------------------------

- I started to make a small amplifier boards which converts +/-10V EPICS signals into -5V to +30V PZT outs.

- The OPAMP is OPA452 which can deal with the supply voltages upto +/-40V. We will supply +/-30V. The noninerting amp has the gain of +2.

- It uses a 15V zener diode to produce -15V reference voltage from -30V. This results the output voltage swing from -5V to +35V.
The actual maximum output is +30V because of the supply voltage.

- On the circut test bench, I have applied +/-5V sinusoidal to the input and successfully obtained +5V to +25V swing.

- The board will be put on Ben's board today.

Attachment 1: P9151574.JPG
P9151574.JPG
Attachment 2: P9161576.JPG
P9161576.JPG
Attachment 3: P9161577.JPG
P9161577.JPG
  5447   Sat Sep 17 14:04:45 2011 KojiUpdateIOOPZT1 driver in place

The PZT driver is now in place. The actual PZTs are not connected yet!

It is accommodated on Ben's connector adapter board.

The panel has additional connectors now: two inputs and a power supply connector.

The supply voltage is +/-30V (actual maximum +/-40V), and the input range is +/-10V
which yields the output range of -5V to 30V. The gain of the amplifier is +2.

It is confirmed that the HV outputs react to the epics sliders although the PZT connector is not connected yet
so as not to disturb the locking activity.

When we engage the PZT connector, we should check the HV outputs with an oscilloscope to confirm they
have no oscillation with the capacitances of the PZTs together with the long cable.

Attachment 1: P9171579.JPG
P9171579.JPG
Attachment 2: P9171580.JPG
P9171580.JPG
  5449   Sun Sep 18 15:34:09 2011 KojiUpdateAdaptive FilteringModifications to LSC, RFM models, added OAF model

[Koji Kiwamu]

This modification of the LSC model made the rows of the LSC output matrix shifted. This caused the ASS scripts nonfunctional.

Kiwamu fixed the channel names in the ASS script.

Quote:

[Jenne, Mirko, with supervision from Jamie]

I modified the c1lsc model to have shmem outputs that go from the degrees of freedom to the OAF, and shmem inputs from the OAF's output to sum into the DoFs, just like Yoichi's FF stuff.  I also removed the old OAF_OUT, because it would only allow me to select one DoF at a time, and I will eventually want the ability to do multiple amounts of OAFing at the same time.  Hopefully.

 

  5450   Sun Sep 18 15:57:00 2011 KojiUpdateIOOThe PZT driver engaged to PZT1

[Koji Kiwamu]

The pzt driver for PZT1 has been installed.
As there was unknown resistive connection in the vacuum chamber as described below,
the PZT out cable at the PJ driver module should always be disconnected.
The sensor cables have no problem to be connected to the controller.
In fact, they are a good monitor for the state of the PZTs.

In this configuration, Pitch and Yaw direction of PZT1 is under the control of the EPICS value as we expected.


Details:

- At the beginning, we tested the PZT driver output with low voltage level (~10V). We did not see any oscillation of the opamps.
  The pitch output was observed to be OK, while the YAW output exhibited a half of the expected output voltage.
  The opamp was holding correct voltage, however the voltage after the 1K output resister was about a half.
  This indicated there was a voltage division happening.

- The cause of the voltage division was tracked. We found that the yaw red (=hot) line is connected to pitch black
  in the vacuum chamber with a resistance of 1.4kOhm. The black cables are shorted to the ground level in the PJ driver.

- We decided to unplug the PJ's cable so that we can isolate the black cables while hoping the PZTs were drived only
  by the red and white cables. And they did.

- This means that we should not connect the PZT driving cable to the PJ's driver. The sensors have no problem to be connected.

- Pinouts:

DSUB25
|. .|
|. .|
|. o|  5
|o  | 17
|  o|  4 
|o  | 16   Yaw Black
|  o|  3   Pitch Black
|o  | 15   Yaw White
|  o|  2   Yaw Red
|o  | 14   Pitch White
 \ o|  1   Pitch Red
  \-+

* Pitch White and Yaw White are connected to the ground at the amplifier side.
* Yaw Red and Pitch Black is connected with 1.4kOhm and isolated from the others.


  5451   Sun Sep 18 16:42:00 2011 KojiBureaucracyEnvironmentClean up your mess

Mess in the lab is increasing. Kiwamu and I had to clean up some stuffs to continue our work.
(i.e. some components were disturbing to open the lid of the tables.)

Basically the tools/equipments/component/cables/digital cameras/lens caps/IR viewers
you have used for the day should be cleaned up at the end of the day.

If one likes to leave a temporary stuff, leave a note to indicate by whom, for what, how long
it will be kept like that, and when one is going to back there with contact info like the cell phone #.

  5473   Tue Sep 20 02:21:10 2011 KojiUpdateLSCLSC MEDM screen cleaning up

I have made some cleaning up of the LSC-related MEDM screens.

- LSC overview screen: ADC OVFL and WFAA indicators are now correctly matched to it associated PD signals.

- Whitening screens now have the correct indication of the associated PD signals.

- LSC Ctrl screen, which is invoked from the overview screen by clicking the servo filters, now has the switches of the servo filters.

- LSC tab of the sitemap was cleaned up by removing the broken links.

  5481   Tue Sep 20 15:39:57 2011 KojiUpdateSUSfree swinging test in vacuum condition

Can't we use Yuta's auto-Q adjust script?

 http://nodus.ligo.caltech.edu:8080/40m/3723

Edit by KI :

Of course we can use it but first we have to fix some pynds sentences since his script was written for the OLD pynds.

  5492   Tue Sep 20 23:59:53 2011 KojiSummaryLSCPlan to update the LSC code for multiple lock-ins

DRMI team needs to use at least three lockins on LSC

  • Increase the number of the lockin matrix  done
  • Duplicate lockin modules in the LSC code  done
  • modify the main LSC screen done
  • modify the lockin screen done
  • modify the lockin matrix screen done
  5498   Wed Sep 21 14:28:25 2011 KojiSummaryLSCThe LSC code/screen modification for LSC LOCKINs

The LSC code has been modified

- The code was modified, compiled, and installed.

- The code is now running. FB was restarted to deal with the change of the channel names.

- Now we have LOCKIN1, 2, and 3. This required the change of the names from C1:LSC-LOCKIN_.... to C1:LSC-LOCKIN1_...

 

- The LSC screen has also modified. It has three lockins on the screen.

- The corresponding matrix screens have been modified/created and linked from the main screen.

- I need to make the screens more cool but the locking team can start to use those lockins.

  5516   Thu Sep 22 11:50:37 2011 KojiUpdateLSCLocking status update

Both loops basically have no phase margins. i.e. unstable. How can you lock PRMI with these servos?

Quote:

The following rough swept sine plots are the OLTs for MICH and PRCL. The gain setting was -10 and 0.5 for MICH and PRCL, respectively. Integrators were off. Looking at the measured plots, MICH has about 300 Hz UGF, when the gain is -20, and PRCL has about 300 HZ UGF, too, when the gain is 0.8.

 

  5522   Thu Sep 22 18:33:01 2011 KojiSummaryLSCThe LSC screen modification

As per the request of Anamaria, I have added the slider of the demodulation phase for each RF PD screens.

Attachment 1: PD_screen.png
PD_screen.png
  5528   Thu Sep 22 23:18:51 2011 KojiSummaryLSCThe LSC screen modification

 

C1LSC_RFPD.adl screen was modified to have more information.

Attachment 1: C1LSC_RFPD.png
C1LSC_RFPD.png
  5539   Sat Sep 24 17:12:54 2011 KojiUpdateLSCRealignment of REFL / Some 3f PRMI locking / Recycling Gain

[Koji Suresh]

Activity on Friday evening

- The REFL path has been thoroughly aligned
As I did not like the REFL spot misaligned on the REFL CCD, we went to the AP table.
Many optics had the spots not on the middle of the optic, including the PBS whose post was not fixed on the post holder.
We aligned the optical paths, the RF PDs, and the CCD. The alignment of the PD required the use of the IR viewer.
One should not trust the DC output as a reference of the PD alignment as it is not enough sensitive to the clipping.

We aligned the optical paths again after the reasonable alignment of PRM is established with the interferometer.
"Next time when you see REFL spot is not at the center of the camera, think what is moved!"

- The REFL165 PD is disconnected from the power supply
I found that the REFL165 PD is producing 7.5V output at the DC monitor no matter how the beam is blocked.
As I could not recover this issue by swapping the power connector at the LSC rack, I disconnected the cable
at the RFL165 PD side. I need to go through the PD power supply circuit next week.

- PRMI alignment policy of the night

Kiwamu has aligned Y-arm some time ago (Thursday evening?). I decided not to touch ITMY.
So the Michelson is aligned by ITMX, PRC is aligned by PRM.

- Michelson locking

The short Michelson was locked with AS55Q and the MICH filter. We could use the gain of +/-20 for locking,
and could increase it up to ~+/-250. At the max gain, the all three integrators and the two resonant gains
could be activated. The sign depends on which fringe you want at the AS port (bright or dark).

In this condition, the output of the POXDC channel (which is actually the POY DC out -- c.f. This entry
is used to determine the internal power. It was ~70cnt.

- PRMI locking

Then the PRMI was locked. There was some confusion of the gains because of the limitters at the servo filters
(which yielded the locking with 1bit outputs no matter how much the gains were....)

After all, I decided to use REFL33I for the PRCL for the test. The PRCL gain was -0.3~-1.0 for the carrier lock, but
was highly dependent on the alignment. i.e. if accidentally hit the high power recycling gain, it oscillated easily
and the lock was lost. Probably this was the first 3f locking at the 40m in the current optical config, if
Kiwamu did not do that secretly. The SB lock was also obtained by flipping the sign of the PRCL servo.

The difficulty we had was the instability when the recycling gain became big. We were monitoring the POXDC
(i.e.DCout of the POY PD). When this exceeds 5000, many glitches appears in the LSC signals and disturbs the lock.
This was not the fringes from neither the arms nor the SRC.

The observed POY DC with the carrier resonant PRMI was 5000~8000vcnt (momentary).

  5541   Sat Sep 24 20:14:36 2011 KojiUpdateLSCRough estimation of the PR gain

 

POXDC (i.e. POY DCout)
PRM misaligned: 70cnt
CA resonant PRMI: ~8000cnt (max)

REFLDC

PRMI antiresonant = 5200cnt
PRMI resonant = ~3000cnt
==> Visivility = 0.6

PRM
Transmissivity: TR=0.0575, tR=sqrt(TR)


Rough estimation of the power recycling gain (assuming perfect mode matching)

PPRM_mialign = Pin tR2
PPRM_resonant = Pin [tR/(1-rR rMI)]2

G = tR2 PPRM_resonant / PPRM_mialign = 8000/70*0.0575 = 6.5

This is way too low compared with the design (G>40)
This corresponds to rMI2=0.885 (loss of 10%) in the power recycling cavity.
But this yields visibility of 16%, instead of 60% which we saw. This is inconsistent.


If mode matching is not perfect, effective incident power of PRMI decreases
and this discrepancy may be explained

Pin = Pjunk + (Pin-Pjunk)

PPRM_mialign = Pin tR2
PPRM_resonant = (Pin-Pjunk) [tR/(1-rR rMI)]2

PREFL_antires ~ Pin
PREFL_resonant = Pjunk+(Pin-Pjunk)[-rR+(tR2 rMI)/(1-rR rMI)]2

===>

PPRM_resonant / PPRM_mialign = (1-Rmm) /(1-rR rMI)2=8000/70
PREFL_resonant /PREFL_antires= Rmm+(1-Rmm)[-rR+(tR2 rMI)/(1-rR rMI)]2=0.6

here Rmm= Pjunk/Pin is the mode matching ratio

Solving the last two equations, we obtain

Rmm=0.6,
rMI2= 0.939 (loss of 4-5%)

Can we believe that the mode matching is 60% and the loss is 5%???

  5549   Mon Sep 26 17:49:51 2011 KojiUpdatePSLc1psl

[Koji Suresh]

c1psl has got frozen during our ezcaread/write business.
After the target was rebooted and we lost the previous setting as there was no burt snapshot for the slow targets since Dec 13, 2010.

It seems that burtrestore is essential for the bootstrapping of the MC servo, as the auto locker script refers the locking parameters
from the PSL setting values (C1PSL_SETTINGS_SET.adl).

Jenne is working on the recovery of the snap-shotting for the slow targets.

  5551   Mon Sep 26 20:04:03 2011 KojiUpdatePSLMC lock has been recovered

[Kiwamu Suresh Koji]

Some main parameters of the PSL has been recovered using Dataviewer and some screen snapshots, as seen in the screenshots below.

Attachment 1: snapshot1.png
snapshot1.png
Attachment 2: snapshot2.png
snapshot2.png
Attachment 3: snapshot3.png
snapshot3.png
  5559   Tue Sep 27 20:02:19 2011 KojiUpdateSUSWatchdog rearmed

I came to the control room and found the PMC and IMC were unlocked. ==> Relocked
I found the watch dogs of the vertex suspensions are tripped.

I checked the data for the past 6 hours and found they are independent events.
The unlock of the MCs occured 4 hours ago and the watchdogs tripped 2 hours ago.

The suspension damping was restored at around 7:50PM PDT.

  5584   Fri Sep 30 08:40:02 2011 KojiUpdateLSClength fluctuations in MICH and PRCL

Tip-Tilts has almost no isolation up to 3Hz, and isolation of about 0.5 up to 10Hz.
They have vertical resonances at around 20Hz.

See Nicole's entry

Quote:

noise.png

 

  5591   Fri Sep 30 19:12:56 2011 KojiUpdateGeneralprep for poweroutage

 

 [Koji Jenne]

The lasers were shutdown

The racks were turned off

We could not figure out how to turn off JETSTOR

The control room machines were turned off

FInally we will turn off nodus and linux1 (with this order).

Hope everything comes back with no trouble

(Finger crossing)

  5592   Sat Oct 1 17:47:21 2011 KojiSummaryGeneralRecovery from the power shutdown

[Steve Koji Kiwamu]

- The storage on linux1 and linux1 itself (with this order) were turned on at 10:30am

- Kiwamu restored the vacuum system

   => opened V4, started TP1 (maglev) and opened V1.

      The pressure went downfrom 2.5 mTorr to the normal level in about 20 minutes.

- A regular fsck of linux1 was completed at 5pm

- Nodus was turned on. Mounting /cvs/cds succeeded

- The control room computers were turned on

- The rack power for FB turned on, FB and megatron started.

- Kiwamu and Koji went through all of the rack powers and started the slow and fast machines.
As we found Solensen for -15V at ETMX was current limited. +/-15V were turned off for now.
==> Kiwamu turned on Solensen again for investigation and found it became okay.
It's now ON.
 
- c1sus and c1ioo had many red lamps on the FE status screen.
Ran killc1XXX for all of the FE codes on c1lsc and c1ioo.
Then, made software reboot (sudo shutdown -r now)
All of the FEs shows green (after some randome clicking of DIAGRESETs)

- HVs on 1X1 were turned on. The are not vacuum HV, but used only in the air

- Turned on the RF generation box and the RF distribution box

- burtrestore slow machines (c1psl, c1susaux, c1iool0, c1iscaux, c1iscaux2, c1auxex, c1auxey)

  5613   Tue Oct 4 15:43:10 2011 KojiUpdateIOOclosed the shutter before the MC

The shutter before the MC was closed at 3:30 as I started working on the RFAM.

MC REFL (INLOCK): 0.6~0.7
MC REFL (UNLOCK): 6.9
MC TRANS: 50000~52000

  5617   Tue Oct 4 19:06:46 2011 KojiUpdateIOOclosed the shutter before the MC

Finished the work at 6:30

MC REFL (INLOCK): 0.50-0.52
MC REFL (UNLOCK): 6.9
MC TRANS: 54400~547000


RFAM level

Before the work: -48.5dBm for 1.07VDC (both 50Ohm terminated)

Right after the work: -80dBm for 0.896VDC (both 50Ohm terminated)
10min after:   -70dBm
1hour after:   -65dBm
3hours after: -62dBm
1day after (Oct 5, 20:00):    -62.5dBm
2days after (Oct 6, 23:20): -72.5dBm
3 days after (Oct 7, 21:00): -57.8dBm

Quote:

The shutter before the MC was closed at 3:30 as I started working on the RFAM.

MC REFL (INLOCK): 0.6~0.7
MC REFL (UNLOCK): 6.9
MC TRANS: 50000~52000

 

  5628   Fri Oct 7 11:45:24 2011 KojiSummaryLSCPOY11 installed, 55MHz PD at POY removed

POY11 PD was installed last night. The lock of the Y arm was confirmed with the POY11I signal.

- The DC transimpedance was modified to be 1010V/A as the incident power is tiny.

- The demodulation phase of the roughly adjusted (148deg) to have PDH signal at the I-phase.
 
The comparison with AS55I signal exhibits that POY11I have ~150 times weaker signal with 45dB whitening.
 
(In total 25000 times weaker.)

On the way to make POY11 functioning, there were many fixes at the LSC rack...


Details:

- The PD interface cards (power supply for the RFPDs) were checked:
So far the two card at the right hand side were checked. 

Desipite the previous entry reported the issues on those boards, they did not show any problem yesterday.

One hypothetical possibility is the enabling switches that is controlled from the old slow epics targets.

- POY55 was removed

This 55MHz PD is supposed to be installed at POP.
The PD, an RF cable, an RF amp, the power supply of the RF amp were removed.

- POY11 was installed

The PD was placed where the 55MHz was placed.

The beam was aligned on the diode using the IR viewer and the digital multimeter.

The power supply cable and the RF cable for POY on the ITMY table were used.

There were an ND filter on the POY beam path. It was removed.


- On the LSC rack
The PD RF was connected to the patch panel at the top of the rack.

There were loose connectors on the patch panel. Some connectors were tightened on the panel.

I found that POY11 and POX11 had I&Q signal reversely connected to the whitening board.
   ==> These were fixed but
require the orthogonality test again for those channels.



The I phase output of the AS11 demod board had a broken connector. 

The onboard SMA has got disintegrated because of too much twist on the connector.
The board was once removed from the rack and the connector was fixed using a heat gun and soldering.

The DC signals were checked. POYDC was not correctly connected. POYDC were correctly connected to the POYDC channel.

- CDS
c1lsc was found with the RFM frozen.
The c1lsc machine was soft-rebooted after stopping all of the RT processes.

Once the RT processes came back, they were all burtrestored.

- PDH locking
Restored Y-arm. Locked it with AS55Q.
Ran ASS alignment for Y-arm.
100cnt 150Hz sinusoidal signal is applied to ETMY

Measured the PSD of AS55Q, POY11I, and POY11Q.
Adjusted the demod phase so that the excitation could be minimized in POY11Q.


  5629   Fri Oct 7 11:53:47 2011 KojiUpdateLSCDRMI locked and some plans

- REFL165 PD to be fixed (shows constant high voltage at the DC out)

- Make POP22/110 PD

- Install AS11? or use it as POX11?

- Install POP55

  5634   Fri Oct 7 22:41:05 2011 KojiConfigurationGeneralScript backup fixed

Script backup regularly runs on op340m by crontab,
but the true backup were not taken since Oct 16, 2010
as the backup program was looking at the old script directory.
/cvs/cds/script/backupScripts.pl was modified to look at the new script directory.

OLD COMMAND:

$command = "cd /cvs/cds/caltech; /usr/sbin/tar cfX - $EXCLUDE_LIST scripts | bzip2 > $ARCHIVEDIR/scripts_$curdate.tar.bz2";

NEW COMMAND:

$command = "cd /opt/rtcds/caltech/c1; /usr/sbin/tar cfX - $EXCLUDE_LIST scripts | bzip2 > $ARCHIVEDIR/scripts_$curdate.tar.bz2";

  5640   Mon Oct 10 00:01:26 2011 KojiUpdateLSCFirst attempt to estimate mode matching efficiency using interferometer

"^2"s are missing in the second equation, but the calculation results seem correct.

PRX and PRY have different mode matching because of the Michelson asymmetry.
Are individually estimated mode matching indicates any sign of reasonable mode mismatch?
(The difference can be very small because the asymmetry is not so big.)

  5644   Mon Oct 10 15:41:56 2011 KojiUpdatePSLPMC aligned

[Koji Suresh]

The steering mirrors for PMC were aligned. The transmission went up from 0.779 to 0.852.

  5664   Thu Oct 13 23:58:38 2011 KojiUpdateLSCfixing REFL165

I already have reported in this entry that REFL165 shows too high DC output which does not depend on the light level on the diode.
Today I removed REFL165 from the table and inspected it.

The diode has been burnt as shown in the first picture (left).
The window is smoked, and the photo sensitive surface has been removed from its base. It moves in the can.

The burnt diode was replaced to the new one.
The new one shows ~30% better capacitance of ~50pF
and I had to increase the inductance from 14nH (i.e. 15nH//220nH) to 18nH.
After some struggles to increase/decrease the stray inductance by moving the SMD capacitors a little, the resonance is reasonably tuned to 166MHz.

The comprehensive test will be performed shortly.

Attachment 1: PA131612.jpg
PA131612.jpg
Attachment 2: PA131618.jpg
PA131618.jpg
  5671   Sat Oct 15 16:42:08 2011 KojiUpdateLSCTesting REFL165

Test results of new REFL165 (the first attachment)

- The resonant freq 166.2MHz, Q=57 (previous Q was ~7)

- If we believe the TF measurement, the transimpedance at the resonance is 7.8k [V/A] and the shotnoise intercept current of ~1mA.
The linearity of the peak was confirmed by changing the modulation level of the beam.

- There is a riddle: the white light test indicates 4.5k [V/A] and 2.8mA for those numbers.
There are big descrepancies from those by the TF measurements.


Further analysis of the descrepancies:

Using the noise measurements with different DC current levels, the transimpedance for each frequency can be reconstructed.

Does this indicate the satiration by the white light???

- The TF measurement shows consistent mag&phase relationship at the resonance (c.f. LISO fit).
So this steep resonance is not an artifact by a noise or glitch but the real structure of the electronics.

- The TF measurement has been done with the photocurrent of ~0.3mA, while the transimpedance measurement
with the white light illumination has the practical effect only when the DC photocurrent is larger than 1mA
because of the circuit noise. Does this higher photo current affected the resonance?

- The off-resonant transimpedance agree with the TF measurement as far as we can see with those measurements.
This may mean that the actual resonant structure has been affected in the white light measurement.
(i.e. not the saturation of the RF opamp which causes the change of the gain at any freq.)
Is the above mentioned higher DC current causing the change of the diode capacitance or other property of the diode or the inductors???

Attachment 1: REFL165_test_111014_KA.pdf
REFL165_test_111014_KA.pdf REFL165_test_111014_KA.pdf REFL165_test_111014_KA.pdf REFL165_test_111014_KA.pdf
Attachment 2: REFL165_transimpedance2.pdf
REFL165_transimpedance2.pdf
  5672   Sat Oct 15 17:06:20 2011 KojiUpdateLSCInstallation REFL165

REFL165 was installed on the AP table last night.

Meanwhile I found the DC power level at the REFL PDs were 0.8~1.2V if the PRM is aligned and the IFO is not locked.
This corresponds to 16~24mA (20~30mW). This is too big.

The HWP of the REFL path were adjusted so that we have 6~10mA (8~12mW) on each PDs.

  5678   Mon Oct 17 11:40:44 2011 KojiUpdateLSCREFL165 removed from the table

REFL165 removed from the table for the C(V) test

  5681   Mon Oct 17 22:20:42 2011 KojiUpdateLSCREFL165 removed from the table

Quote:

REFL165 removed from the table for the C(V) test

The PD was returned on the table.

The C(V) compensation path was modified and the change of the resonant freq was cancelled.
A more precise analysis comes later.

  5685   Tue Oct 18 10:04:41 2011 KojiUpdateLSCREFL165 removed from the table

The original REFL165 had ~50MHz/A dependence on the DC photocurrent.
The resistr R21, which was 2670 Ohm contrary to the original drawing, was replaced to 532 Ohm
to increase the feedforward gain by factor of 5.

The resulting dependence is reduced to ~0.5MHz/A although it has Q reduction of ~20% at 6mA.

Some concerns:

These transfer functions were measured between TEST IN and RF OUT while the diode was illuminated with the white light from a light bulb.

There looks some thermal effect on the resonant freq. If the white light illumination is suddenly removed, the bias compensation
is immediately removed but the resonance takes some time (~min) to come back to the original freq.

I am afraid that the light bulb gave too much heat on the surrounding PCB and lead unnecesarily high level dependence of the resonant freq on the DC current.

Or, if this thermal effect comes from the power consumption on the diode itself, we need to characterize it for aLIGO.

In order to check this, we need a test with the 1064nm illumination on the diode in stead of the light bulb.

Attachment 1: REFL165_original.pdf
REFL165_original.pdf
Attachment 2: REFL165_new.pdf
REFL165_new.pdf
Attachment 3: REFL165_schematic_111017_KA.pdf
REFL165_schematic_111017_KA.pdf
  5703   Wed Oct 19 17:21:16 2011 KojiSummaryLSCModification on the RFPD interface cards

I have modified all of the three RFPD interface cards to be enabled permanently.
This prevents an accidental disabling caused by a stray voltage of the logic input (or whatever),
which was reported in multiple occasions by Anamaria and me.

The logic ICs (74LS04) for buffering of the EPICS switches were removed by 14pin sockets with additional wires soldered.
The modification shorts the inputs to the second logic chips, resulting in the permanent enabling of the PD circuit.

Attachment 1: D990543-B_mod.pdf
D990543-B_mod.pdf
  5708   Thu Oct 20 01:40:33 2011 KojiSummarySUSMC2 Misaligned 2:27PM on Wednesday

There looks some activity at around MC2 on Wednesday afternoon.
It caused the misalignment of MC2. Misalignment was not found in MC1/3.

It seems that the incident beam on the MC was aligned in the evening.
This increased the MC transmission but it is vibible that the spot on MC2 is shifted from the center.

We need an action on this issue tomorrow in the daytime.

Attachment 1: MC2_misalign.png
MC2_misalign.png
  5715   Thu Oct 20 18:42:47 2011 KojiUpdateComputer Scripts / ProgramsWhere should the "Update Snapshots" of screens live?

The following directory exists. We can apply this convention to all of the models.

/cvs/cds/rtcds/caltech/c1/medm/c1lsc/snap

Quote:

While trying to implement the regular yellow shell script button in MEDM for my new OAF screen, I noticed that the update snapshot stuff in all of the buttons that I checked (including IFO Align and LSC Overview) are pointing to folders in the old /cvs/cds/caltech/ area.  Also, I think some of the folders that it's looking for don't exist anymore, even in the old system.  So.  Has anyone thought about where the snapshots should live in the new world order?  Previously they were in ...../medm/c1/subsystem/ .  Maybe we should make a snapshots folder in each subsystem's medm folder, at the same level as the 'master' folder for the custom screens?  This is my current proposal.

Unless someone objects / has a better plan / knows why they're still pointing to the old place, I'll do this in the morning, and work on changing all the buttons to point to the new place.

 

  5745   Thu Oct 27 03:32:45 2011 KojiSummaryIOORFAM monitor progress

[Suresh, Mirko, Koji]

A cable from the stochmon box to the cross connect for the EPICS ADCs is installed.

The power supply and the signal outputs are concentrated in a single DSub 9pin connector
that is newly attached on the box.

The connection from the stochmon side of the cable and the EPICS value was confirmed.
The calibration of them looks fine.

To do:
- Once the stochmon box is completed we can immediately test it.
- The EPICS channel names are still as they were. We need to update the database file of c1iool0, the chans file for the slow channel.


The pinout is as following

-------------
| 1 2 3 4 5 |   Female / Inside View
\  6 7 8 9  /
 \---------/

1 - 11MHz Signal
2 - 30MHz Signal
3 - 55MHz Signal
4 - NC
5 - +5V supply
6 - 11MHz Return
7 - 30MHz Return
8 - 55MHz Return
9 - Supply ground

  5795   Thu Nov 3 15:14:22 2011 KojiUpdateCDSCSS/BOY installed on pianosa

How to run/use CSS/BOY

(PREPARATION)

0) Everything runs on pianosa for now.

1) type css to launch CSS IDE.

2) You may want to create your own project folder as generally everything happens below this folder.

=== How to make a new project ===
- Right-click on tree view of Navigator pane
- You are asked to select a wizard. Select "General -> Project". Click "Next".
- Type in an appropriate project name (like KOJI). Click "Finish"
- The actual location of the project is /home/controls/CSS-Workspaces/Default/KOJI/ in the above example

(PLAY WITH "Data Browser", THE STRIPTOOL ALTERNATIVE)

1) Select the menu "CSS -> Trends -> Data Browser". A new data browser window appears.

2) Right-click on the data browser window. Select the menu "Add PV". Type in the channel name (e.g. "C1:LSC-ASDC_OUT16")

3) Once the plot configuration is completed, it can be saved as a template. Select the menu "File -> Save" and put it in your project folder.

4) Everything else is relatively straightforward. You can add multiple channels. Log scaling is also available.
I still don't find how to split the vertical axis to make a stacked charts, but I don't surprise even if it is not available.
CSS_snapshot1.png

(HOW TO MAKE A NEW "BOY" SCREEN)

0) Simply to say BOY is the alternative of MEDM. The screen file of BOY is named as  "*.opi" similar to "*.adl" for MEDM.

1) To create a new opi file, right-click on the navigator tree and select the menu "New -> Other".

2) You are asked to select a wizard. Select "BOY -> OPI file" and click "Next".

3) Type in the name of the opi file. Also select the location of the file in the project tree. Click "Finish".

4) Now you are in OPI EDITOR. Place your widgets as you like.

5) To test the OPI screen, push the green round button at the top right. The short cut key is  "CTRL-G".
OPI_EDITOR.png

(HOW TO EDIT AN EXISTING OPI FILE)

1) Right click an OPI file in the navigator tree. Select the menu "Open WIth -> OPI Editor". That's it.

(HOW TO CONVERT AN EXISTING ADL FILE INTO OPI FILE)

1) You need to copy your ADL file into your project folder. In this example, it is /home/controls/CSS-Workspaces/Default/KOJI/

2) Once the ADL file is in the project folder, it should appear in the navigator tree. If not, right-click the navigator pane and select "Refresh".

3) Make sure "ADL Parser" button at the left top part is selected, although this has no essential function.
This button just changes the window layout and does nothing. But the ADL Tree View pane would be interesting to see.

3) If you select the ADL file by clicking it,the tree structure of the ADL file is automatically interpreted and appears in the ADL Tree View pane.
But it is just a display and does nothing.

4) Right-click the ADL file in the navigator pane. Now you can see the new menu "BOY". Select "BOY -> Convert ADL File to OPI".

5) Now you get the opi version of that file.
The conversion is not perfect as we can imagine. It works fine for the simple screens.
(e.g. matrix screens)
But the filter module screens get wierd. And the new LSC screen did not work properly (maybe too heavy?)
ADL2OPI1.png ADL2OPI2.png

(HOW TO RUN OUR SHELL/PERL/PYTHON SCRIPTS FROM BOY)

CSS has javascript/python scripting capability.
I suspect that we can make a wrapper to run external commands from python script although it is not obvious yet.

  5798   Thu Nov 3 17:04:23 2011 KojiUpdateGreen LockingSHG temperature (YARM)

Changing the crystal temperature changes the laser frequency. This will causes the beat note missing at the vertex.

In other words, you will find the beat note at the vertex when the actual temperature of the crystal is reproduced as before,
no matter how the dial setting/temp voltage input is.

  5804   Fri Nov 4 00:13:24 2011 KojiUpdateLSCXARM locked with POX11

XARM lock was achieved by POX11_I

Summary:

- The  whitening gains of POX11_I and Q are 42dB so that POX11_I have the same amplitude as AS55_I

- The demod phase of POX11 was adjusted to eliminate the PDH signal from the Q phase. The phase is  -100.5deg.

- In order to lock the XARM with POX11_I_ERR, I had to increase the trigger threshold from 0.1 to 0.2 as the arm was
kicked with the threshold of 0.1.


Method

- Lock the X arm with AS55_I at the XARM configuration.

- Adjusted POX11 demod phase so that POX11_Q is minimized.

- POX I&Q whitening gains were adjusted. When they are 42dB, POX11_I_ERR and AS55_I_ERR have almost the same signal amplitude.
(In reality, POX11_I_ERR has +1dB larger amplitude.)

- Adjusted POX11 demod phase again with better precision.

- Measured transfer function between AS55_I_ERR and POX11_I_ERR. As the sign was opposite, the demod phase was -180deg flipped.

- Tried to lock the arm with POX11_I_ERR. It did not acquire the lock. The arm looked kicked by the servo.

- Increased the trigger threshold from 0.1 to 0.2. Now the arm is locked with POX11_I_ERR.

Attachment 1: POX11.pdf
POX11.pdf
  5821   Sat Nov 5 14:54:59 2011 KojiUpdateASCASS scripts gone

In any case, the daily backup of the scripts are found in /cvs/cds/caltech/scripts_archive

Quote:

Quote:

Did somebody delete all the scripts in /opt/rtcds/caltech/c1/scripts/ASS ?

 I have moved all the MC_ASS scripts to a directory called MC under ASS 

 

  5851   Wed Nov 9 16:29:36 2011 KojiSummaryLSCCharacterization of the Power Recycled Michelson

Difficult to understand.

The mode matching does not change the recycling gain. It changes the coupling of the incident light into the cavity.
It changes the reflected and accumulated power, but the recycling gain is not affected.

The recycling gain is determined by the optical configuration and the optical loss in the cavity.

In the actual measurement, of course, we should take both of the loss and the mode matching into account.
But this is the issue of the measurement method.

The essential questions are:
How much is the actual recycling gain? And how does it affect the signal extraction?

  5903   Wed Nov 16 02:36:35 2011 KojiUpdateelogrestarted

Basically, elog hangs up by the visit of googlebot.

Googlebot repeatedly tries to obtain all (!) of entries by specifying  "page0" and "mode=full".
Elogd seems not to have the way to block an access from the specified IP.
We might be able to use http-proxy via apache. (c.f. http://midas.psi.ch/elog/adminguide.html#secure)

Or can we tweak the source of elod such that it does not accept "page0"?


GET /40m/page0?mode=full&new_entries=1 HTTP/1.1
Host: 131.215.115.52:8080
Connection: Keep-alive
Accept: */*
From: googlebot(at)googlebot.com
User-Agent: Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)
Accept-Encoding: gzip,deflate

 

Quote:

Elog was hanging. Restarted it with script.

 

  5911   Wed Nov 16 12:21:33 2011 KojiUpdateeloggooglebot (Re: restarted)

- elogd itself is a sort of web server which has no freedom to put our own file, we can not put robots.txt

- If we include elog using proxy in the usual web tree of Apache, we can put robots.txt at the root.

- So far, if we prevent "page0" browse by google, we will be saved for a while.

- It seems that the indexing is set to be refused by the following meta tags. But it does not prohibit googlebot to use "page0" URL, of course.

<META NAME="ROBOTS" CONTENT="NOINDEX, NOFOLLOW">
  5913   Wed Nov 16 17:03:19 2011 KojiUpdateIOOMC2 Shifted in Pitch, corrected by adjusting the pitch bias

MC was not locked for more than 5 hours because of the misalignment.

Noticed that MC2 WFS feedback filters had big outputs (particularly in Pitch).
They were reset to zero.

MC2 was aligned and recovered the lock. Once the WFS is engaged, the transmission returned to the uisual value.

  5916   Wed Nov 16 18:14:09 2011 KojiUpdateIOOMC unlocked and misaligned.

Actually, do we need to reset the filter history at every lock loss of the MC?

Those DC offsets were necessary to keep the alignment good just until the MC is unlocked.
So if we keep the history, we can maintain the good alignment.

ELOG V3.1.3-