Hey, folks.  Please remember to commit all changes to the SVN in a timely manor.  If you don't, multiple commits will get lumped together and we won't have a good log of the changes we're making.  You might also end up just loosing all of your work.  SVN COMMIT when you're done!  But please don't commit broken or untested code.

pianosa:release 0> svn status | grep -v '^?'
M       cds/c1/models/c1rfm.mdl
M       sus/c1/models/c1mcs.mdl
M       sus/c1/models/c1scx.mdl
M       sus/c1/models/c1scy.mdl
M       isc/c1/models/c1lsc.mdl
M       isc/c1/models/c1pem.mdl
M       isc/c1/models/c1ioo.mdl
M       isc/c1/models/ADAPT_XFCODE_MCL.c
M       isc/c1/models/c1oaf.mdl
M       isc/c1/models/c1gcv.mdl
M       isc/common/medm/OAF_OVERVIEW.adl
M       isc/common/medm/OAF_DOF_BLRMS.adl
M       isc/common/medm/OAF_OVERVIEW_BAK.adl
M       isc/common/medm/OAF_ADAPTATION_MICH.adl
pianosa:release 0>

I have setup a shared .bashrc for all the workstations that is symlinked to the normal location on all machines:

controls@rossa:~ 0$ ls -al /home/controls/.bashrc 
lrwxrwxrwx 1 controls controls 23 2012-05-25 15:37 /home/controls/.bashrc -> /users/controls/.bashrc
controls@rossa:~ 0$ 

This should help simplify maintenance considerably.  Editing that file on one machine will edit it for all.  Just edit this one file!  Don't try to get fancy and add extra files!

I also added a bunch of aliases that had previously been missing.  This should help with some of the problems that people had been having.

NOTE: PLEASE DO NOT CHANGE THE DEFAULT SHELL!  We are using bash, because that's what the sites are now using and we want to be as compatible as possible.

You can of course still write scripts in csh/tcsh or use tcsh in a shell if you wish.   Just don't change the default shell for the controls user.

A nicer, better maintained version of tconvert is now supplied by the lalapps package.  It's called lalapps_tconvert.  I installed lalapps on all the workstations and aliased tconvert to point to lalapps_tconvert.

Today I REPOSITIONED THE SEISMOMETERS in order to triangulate noise sources (as Rana suggested).

I re-levelled all of them, locked them, and turned them on. They should be located out of sight, but just in case:

GUR 1 IS DOWN THE X-ARM, behind the interferometer.

GUR 2 IS BETWEEN THE TWO ARMS, BEHIND THE CABLE TRAP THAT RUNS PARALLEL TO THE X-ARM.

STS 1 IS DOWN THE Y-ARM behind the interferometer.

I'll wait a day for them to stabilize (continuing to reset STS-1 every hour or so) and then begin taking data tomorrow morning, depending on the condition of the signal.

Ideally, I'd like a few days' worth of data, so I'll update when I've changed the configuration back to the way it was prior.

 Highlighting good, ALL CAPS LESS SO!

I checked the connections specified in the old Gulap Pin Map and found that they do not correspond to the current values. I mapped out the current connections (in this case, the letter refers to the labeled pin on the mil/spec while the number refers to the pin on the 37 pin DSub, labeled consecutively):

A-1, B-2, C-3, D-4, E-5, F-6, G-7, H-Unused, J-8, K-unused, L-9, M-10, N -11, P-12, S-13, T-Unused, U-14, V-15, W-16, X-17, Y-18, Z-Unused, a-Unused, b-19, c-20, UnlabeledPin-Unused.

There are 20 pins in use of 26 total, which is good because that means Jenne and I can use the ~70m long 24 wire cable to make a new Gurlap 1 cable.

Den and I moved the Streckeisen, Guralp 2, and Trillium seismometers to the isolation box in order to measure the noise of the Streckeisen while we have the Trillium.

Jan and I wanted to measure the ringdown at the IMC. Since the QPD at the MC trans is not fast enough for ringdown measurements, we decided to install a pickoff to include a faster PD while not disturbing much of the current MC trans configuration. The initial configuration had very little space to accommodate the pickoff. So the collimating lens along with the QPD were moved 2 inches closer to the incoming beam. A 50-50 BS was put in front of the QPD and the steering mirror was moved behind to reflect MC trans output to the new PD. The current configuration is shown below with the MC autolocker threshold mentioned in Jenne's elog

The hunt for a faster PD wasn't satisfactory and we found a couple of PDs that were good for measurements actually didn't work after installing them. The one currently installed is also not satisfactorily fast enough for ringdown measurements. We'll hunt for faster PDs at Bridge tomorrow and replace PDA400. Also the IMC unlocked from time to time....may be we were noisy and didn't master the 'interferometer walk' very well.

  The PDA255 is a good ringdown detector - Steve can find one in the 40m if you ask him nicely.

 We found a PDA255 but it doesn't seem to work. I am not sure if that is one you are mentioning...but I'll ask Steve tomorrow!

 I double checked the PDA255 found at the 40m and it is broken/bad. Also there was no success hunting PDs at Bridge. So the MC trans is still in the same configuration. Nothing has changed. I'll try doing ringdown measurements with PDA400 today.

Can you explain more what "broken/bad" means?  Is there no signal?  Is it noisy?  Glitch?  etc.

 The PD saturates the oscilloscope just by switching on the power; with no real signal at all. But Steve helped locating a PD that is not being used at the AP table. So I will check it and replace the current one if it works!

The PD (pda255) at the AP table, close to the MC refl , which Steve mentioned to be not in use, has been removed from the table for testing.

 The PD installed at MC trans to make ringdown measurements has been replaced with the above PDA255. 

Koji opened up the PD and found that the screw connecting the PD to the pole was doing an additional job as well; connecting the power cable to the PD output in the inside. The PD is now fixed! Yippie...we have two PDA255 s at 40m now!!

 I noticed that the IFO restore scripts have some problems. They use burt request files to store and restore the settings. However, the request files contain old channel names.

Especially channels with _TRIG_THRES_ON/OFF are now _TRIG_THRESH_ON/OFF, note the extra "H".

These scripts reside in /opt/rtcds/caltech/c1/burt/c1ifoconfigure/.

I fixed the PRMI_SBres and MI scripts. Someone should fix all other files.

As promised in previous e-log, this log is all about the current online seismic noise classification system.

While we had the BLRMS system already in place (which I helped make), Den realized that we would need better filters for the BLRMS channels, as we wanted a strong cut-off, but we also wanted a short step-response so that we could quickly classify seismic signals. Likewise, having a step response which oscillates is also undesirable as this could lead to false classifications of post-truck signal as trucks as a filter adjusts and then dips back down. Thus, after experimenting with many different filters, Den chose to use a combination of

chebyl("LowPass", 1, 1, 0.03)*chebyl("LowPass", 1, 1, 0.03)

as our low-pass filter. The step response and bode plot are below.

 The next step was to write C code that would implement the feedforward neural network with my newly generated weights.

Next, I had to implement the code in the c1pem model, and normalize the inputs. Below is an overview of the model, and a close up of the C block section.

The above close-up includes the process of normalization (dividing by the square of the incoming signal), feeding through the neural network, and classifying.

Each seismometer channel set (GUR1X, GUR1Y, GUR1Z, GUR2X, GUR2Y, GUR2Z, STS1X, STS1Y, STS1Z) now has channels (and corresponding DQ channels) of the following form:

SEIS_CLASS : The class of seismic noise 1.0 means Earthquake, 0.5 means Quiet, and 0.0 means Truck. (There are only these 3 digital values).

SEIS_CLASS_EQ, SEIS_CLASS_TRUCK, SEIS_CLASS_QUIET: These channels represent the confidence of the neural network's classification. The class of the current signal will have an output of 1, where the other two channels will have an output between 0 and 1 representing the ratio of the neural network's output in that class neuron to the output in the classification vector neuron. To simply - suppose the neural network classified an earthquake. Ideally, the neural network output neurons would have the value [1, 0, 0], and SEIS_CLASS would equal 1.0 for earthquake. However, the output neurons probably read something along the lines of [0.9, 0.3, 0.5] - SEIS_CLASS is still 1.0, but SEIS_CLASS_EQ would be 1.0, and SEIS_CLASS_TRUCK would be 0.5 / 0.9 and SEIS_CLASS_QUIET would be 0.3 / 0.9. The lower the other two signals are, the better - this means that we are more confident in our classification.

The MEDM screen for this system (in the RMS system) has the following form for all seismometer channels (this one is GUR1X):

These are the screens I edited earlier in the summer, with modifications. The bottom filter banks represent the norm of the seismometer signal, which we use to normalize the inputs to the neural network.

Here a close-up of the most important part:

The orange meter on the right points to the current signal type. Here it reads truck - this is ok because it's the middle of the day, and there are a lot of trucks around. The left side represents our confidence in the signal - the signal is classified as a truck, so the "Truck" bar is saturated. The quiet signal bar is very low, which is good since it means that the neural network thinks that it's definitely not quiet. The earthquake bar has some magnitude, since earthquake signals and trucks have some degree of linear non-separability.

How has this been performing? Firstly, all of the seismometer channels have the same classification readout, which is good. Last night, all of the classes were "quiet", with an "earthquake" which occurred when Den jumped around GUR1 to simulate an EQ. This morning it was on "truck" as expected. The filters are still not fine enough to detect individual trucks, but I will continue to monitor the performance over the coming days.

If anyone has ideas on how better to represent this information, please let me know. This was the first thing that came into my head that would work with my MEDM monitor options, and I'm open to suggestions!

I added a widget to the C1PEM_OVERVIEW MEDM screen. The screen shows the nine seismometer channels (GUR1, GUR2, and STS1 X, Y, and Z), the current signal class in dark red, and the overall confidence in the classification, as Rana suggested. The confidence indication thresholds range from 0.1 to 0.9, in intervals of 0.1. Basically, if a signal class is completely dark red, and the other two classes show only white, or, better yet, nothing at all, this means that we have a clear classification. If, however, the other regions have some yellow, or even red indicators, this means that we are not very confident in our signal classification.

This is a screenshot of the widget. The nine seismometer channels are classifying the signal as quiet, which is good both because it's the middle of the night, and because the nine seismometer signals somehow agree (I'd use the word correspond with one another, but that implies a strong level of coherence..). The confidence is high, seeing as there's little indication in the truck and earthquake regions (none whatsoever in the truck, meaning that the signal, given our classification method, could not possibly be a truck, and some in the earthquake region (below 0.1 of the quiet signal classification strength, however), possibly due to low seismic disturbance).

I turned on some filters and gain in the SUS-MC2_MCL filter bank tonight so as suppress the seismic noise influence on MC_F. This may help the MC stay in lock in the daytime.

Koji updated the mcdown and mcup scripts to turn the MCL path on and off and to engage the Boost filters at the right time.

The attached PNG shows the MCL screen with the filters all ON. In this state the crossover frequency is ~45 Hz. MC_F at low frequencies is reduced by more than 10x.

I also think that this may help the X-Arm lock. The number of fringes per second should be 2-3x less.

 Aim: to scan the cavitymodes of IMC

The circuit used: 

 Attachment4

Results obtained:

Attachment 1,2,3

For the current baffle (dia. 40mm) centered along the beamline place at 1.77" from the test mass, the baffle will allow ~8.6mm visibility on the camera from the center of the test mass (in case of ETMY).

*assuming the pick off mirror is placed at the edge of the tunnel

Estimations of the visibility region (r₁ on the test mass) with baffle (aperture size 40mm).

The baffle is installed on the cage at 1.125" from the test mass (distance changed from the previous elog after a double check).

The 40mm aperture is in no way going to help get clear view of the ITMs; 

Required baffle diameter to have a visibility region r₁ = 3 times the beam diameter

We conducted a beam scan on the AP table of the AS beam. We used a lens to focus the beam onto a power meter, and slowly moved a razor blade across the beam using a micrometer, vertically and horizontally both in front of and behind the beam. We also had to block the beam next to the AS beam in order to do this, but is unblocked now. Mike will begin curve fitting the data to try and see if there is a different spot size given by the x-axis vs. the y-axis, and if the lens has any effect.

 The vacuum envelope must be sealed with light doors on o-rings to insure a bug free IFO.  This was a violation!

 {Jan, Manasa}

We tried towards calibrating the RF driver of the AOM. We decided to use the normal power supply for both the driver control voltage and the ALC voltage.  But we could not figure out the type of the ALC port to find a compatible mating connector...it did not match with SMA, SMB or SMP. Finally I wrote to the company and got to know it is a filtered feed through. Now that we know how to control the ALC voltage, we will try looking at the signal for varying ALC voltage and see how that goes. 

But when we tried to see the 2W RF signal through the RF scope, with ALC open, we found that the RF signal was distorted and did not measure 80MHz.  It was lame that we did not get a snapshot 

P.S. The AOM has been left disconnected from the RF driver. 

 {Jan, Manasa}

We started again to calibrate the RF driver. We connected the ALC to the power supply and observed the output RF power on the scope. The RF power did change with ALC voltage, but the RF signal still seems not to be operating at 80MHz 

There is some kind of additional disturbance to the waveform at 80MHz (the frequency of just the waveform with tall peaks or small peaks alone). We made sure we get a snapshot this time!! I am not sure if it will be safe to feed this RF signal to the AOM as such

 AOM driver has been removed from the PSL table for testing. However the AOM is still inside; so there should be no problems with the alignment. 

Mannasa and Unni and I looked at the RF driver for the AOM. It was fine.

With the ALC input left unconnected, with the power supply set to +28V, it was drawing 0.56 A.

By adjusting the modulation input we were able to get 1.1 Vrms into the scope (terminated at 50 Ohms) after going through 2 10dB attenuators. 11 Vrms into 50 Ohms is 33.8 dBm ~ 2W.

The RF power trimpot on the front of the driver is now adjusted so that -0.31 to 0.69 V takes the driver output from off to 2W output at 80 MHz.

The previous distorted signal that Jan and Manasa saw was at a level of ~100 mVrms, which is ~0.5 mW of power. At this tiny drive level, the internal amplifier is not linear and is mostly putting out a signal at ~160 MHz.

We checked by putting a square wave into the modulation input that the RF power from the driver would indeed shut off with a time scale of ~20 ns. Manasa will add a picture to this entry. We are ready now to calibrate the transmitted power of the AOM v. the modulation input voltage and then to measure the step time of the AOM.

Remember: do NOT believe the spec sheet of whatever PD you are using. All commercial PDs are slower than they advertise. In order to measure a <1 us step time you must use a PD with a >50 MHz 'bandwidth'.

    {Jan, Manasa}

We installed the AOM driver back on the PSL table this morning. To calibrate the AOM RF output we connected a 1V dc to the modulation input of the driver and we are convinced with the setup.

Before we direct the rf signal to the AOM, in order to check its diffraction efficiency, we would like to setup an rf PD at the AOM output. We think we have place for a filter and PD after the AOM (replacing a beam dump) and would like to confirm the position before we actually install them. The layout is the picture below showing sweet spots for the new pd to sit. If you think it may disturb the system in any way, let us know!

Changed the list of channels to be written to frames from having the IN1 suffix to OUT. Now we can load the calibration of the channel into the filter module and the DQ channel will be calibrated.

We should do this wherever possible so that our channels will have real calibrations associated with them.
SEIS_GUR1_X_OUT 256
SEIS_GUR1_Y_OUT 256
SEIS_GUR1_Z_OUT 256
SEIS_GUR2_X_OUT 256
SEIS_GUR2_Y_OUT 256
SEIS_GUR2_Z_OUT 256
SEIS_STS_1_X_OUT 256
SEIS_STS_1_Y_OUT 256
SEIS_STS_1_Z_OUT 256
SEIS_STS_2_X_OUT 256
SEIS_STS_2_Y_OUT 256
SEIS_STS_2_Z_OUT 256
SEIS_STS_3_X_OUT 256
SEIS_STS_3_Y_OUT 256
SEIS_STS_3_Z_OUT 256
MIC_1_OUT 2048
MIC_2_OUT 2048
MIC_3_OUT 2048
MIC_4_OUT 2048
MIC_5_OUT 2048
MIC_6_OUT 2048
ACC_MC1_X_OUT 2048
ACC_MC1_Y_OUT 2048
ACC_MC1_Z_OUT 2048
ACC_MC2_X_OUT 2048
ACC_MC2_Y_OUT 2048
ACC_MC2_Z_OUT 2048
XARM_DIFFERENTIAL_MOTION_IN1 256
XARM_DIFFERENTIAL_MOTION_OUT 256
YARM_DIFFERENTIAL_MOTION_IN1 256
YARM_DIFFERENTIAL_MOTION_OUT 256

Next we should up the rate at which the model runs up to 16 kHz so that we can record the microphones at 16 kHz. FM radio has information up to 20 kHz. AM radio goes up to ~8 kHz. We should be at least as modern as AM radio. How do we make the change? How do we make sure the FOTON file stays OK?

I have made some changes to the daily summary file to compensate. New files is /users/public_html/40m-summary/share/c1_summary_page.ini.

The PDA255 that Koji repaired is still not alright. It seems to be saturating again. I've left it in the PD cabinet where it is marked 'PDA 255'. I've asked Steve to order a fast PD at 150MHz, PDA10A because we don't seem to have any at the 40m.

The rf PD and filter have been installed at the earlier proposed spot on the PSL table.  

The SOS coil drivers (Atm2) were moved from 1X1 to 1Y2 location. Is this the best place to locate the  IOO Tip-Tilt steering that will replace the PJ-PZT ?

See 40m wiki T-T

{Jan, Manasa}

We set start to check the performance of the AOM on the PSL table. The AOM driver spits out ~1.5W rf at 80MHz for 1V DC at its modulation input. In order to align the AOM, we reduced the input power to the AOM to ~10% using the QWP between the PBS and the laser. We touched the steering mirror before the AOM...but did not succeed in getting any appreciable first order deflection. We then released the AOM mount and moved it a few microns in and out until we obtained a significant change in power along the zero-order beam from 400mV to 100mV when the rf power was changed from 0 to ~1.5W (by changing modulation input from 0 to 1V).  The AOM was clamped at this alignment and the QWP was rotated to give maximum input power. 

During the course of aligning the AOM, the PMC unlocked and was restored after the alignment. 

All went well without having to make any emergency calls to anyone

We will now have to think about switching the AOM on and off for ringdown measurements. This could be done by either using a high-power rf switch or by switching the modulation DC input between 0 and 1V; whichever will be more comfortable to take many many ringdown measurements.

After the AOM work the beam wasn't well aligned to the PMC. The PMC REFL CCD shows large misalignment in yaw.

 {Jan, Manasa, Den}

We wanted to align the PMC and followed Koji's procedure detailed to us by mail. We touched the 2 steering mirrors in front of the PMC for alignment.

- Stand in front of the PMC.
- Find an oscillosocpe on the shelf in the PSL enclosure.
- This has two signals connected. One is the PMC refl dc.
  The other is the PMC trans dc.
- Minimize the refl. Maximize the trans.
- You have the CRT monitor on the MC chamber.
- Project the image of the PMC refl CCD.
  This should show some what symmetric image like an LG mode.
- Use the dataviewer to see how C1:PSL-PMC_PMCTRANSPD is recovered.

We were able to obtain 0.7 at PMC trans; but the PMC was never really stable dropped from 0.7 to 0 abruptly from time to time.

Jenne and Jamie also find that the PMC is behaving very weird 

Summary: Problem unresolved 

 Can someone detail what "weird" means? Is it singing old songs from Guns & Roses?

 It isn't singing Jan..it's dancing between 0.7 to 0 and we are not able to figure out whose the DJ ; there seems to be something else that is controlling the PMC as there is no coordination between what we do (tweaking the mirrors) and what we observe (the PD signals).

Do more investigation to understand what is causing the power reduction.

Is the alignment inadequate? Check the in-lock ccd image.

Is the incident power reduced? (by what?) Use dataviewer.

Is the AOM doing something? Is it active? Then how much power is it eating?

BY THE WAY, how the deflected beam is dumped?
If you don't have anything for blocking the 1st order beam, you have to expect Steve coming to you.

 Here I am attaching the schematic diagram of the experimental set-up for IMC cavitymode scanning. A 30- 45MHz scanning signal generated by Agilent 4395A network analyzer enters EOM, which in turn modulates the laser beam entering IMC. The cavity response can be verified from reflected/transmitted beam.

I worked with the reflected beam last days. But I got no clue about the percentage of  reflected light reaching the photodiode and also the photodiode response. I would like to measure the power reaching photodiode and also would like to perform the test with transmitted beam - on wednesday if possible.

 I've added calibration gains to Guralp (to um/sec) and EM172 (to Pa) channels.

We can run PEM at 16 kHz. I think Foton file stores both sos-representation and filter commands which are independent of the sampling frequency, so it should be possible to change model sampling frequency quickly.

In fact, we can save data at 64 kHz from iop models. I've done this once with MC_F channel. However, I did not test EM172 noise at frequencies > 1 kHz.

The PMC has been aligned and is all happy happy 

I have installed an  iris to dump the higher order beams deflected by the AOM. After installing the iris, I found that the PMC trans dropped to 0.58V and the PMC misaligned in pitch. So I've touched the 2 steering mirrors before the PMC. Now it is satisfactorily locked with PMC trans at 0.84.

I have also checked the alignment with AOM switched on. PMC trans drops to 0.15 with AOM on and comes back to 0.84 when AOM is switched off without losing lock .

 Rijuparna, Manasa

Today I have checked the optical layout of the MC transmission RFPD table and measured the laser powers at different points. Manasa helped me for that. I found the power entering the RF photodiode is 0.394mW while the transmitted power of the cavity is 2.46mW. (I will give the diagram later).

I'm set on the mission to get the new bigger endtables setup for the auxiliary green laser; now that the tables are already here.

I want to have everything documented in this same thread for future reference. It has been a pain trying to filter relevant elogs. I'll be working on the layout redesign one at a time....starting with the ETMX end.

This is the simplest cartoon layout of  ETMX endtable (not the actual table layout):

I have been searching through the elogs for the beam parameters measured earlier. I'm assuming they would not have changed much and will make calculations based on them.

However, we will have to change a few not-so-good mounts and include/exclude some optics.

P.S. HR (steer) are necessary steering mirrors and HR are just folding mirrors for the drawing.

With reference to measurements made earlier: elog, 

Beam parameters for Innolight 1W NPRO are:

w_x0 = 160 um 

w_y0 = 181.1 um

z_0x = -9.17 cm

z_0y = -10.19 cm

The beam is clearly elliptical.  We will introduce an additional pair of cylindrical lenses to circularize the beam before it enters the faraday.

I made calculations for the beam divergence ratio and checked with thor labs catalogue of cylindrical lenses to find pairs that will match the ratio. 

I propose to use lenses with focal lengths f₁ = 22.2 mm and f₂ = 25 mm. The beam diameter after the lenses will be d_x = 164.05 um and d_y = 163.19 um.

These fs are too short.

I have attached the possible layout of the optics on the new ETMX endtable. More optics have been added when compared to the early cartoon layout considering that we need additional steering mirrors for reasons like: the table height in and out-of vac are different and several mounts have restricted movement in certain degrees of freedom. 

As you can see, there is enough room for filters and other last time additions that may arise.

I will proceed with calculations based on the distances from the CAD drawing and the spec of the optics if there are no comments or suggestions about the layout.