The 785 analyzer in the 40 had a wonky hard to read screen. I was hoping that a new white CRT would fix all the problems. 

I installed a white CRT, which didn't fix the wonkyness, but I adjusted the CRT position, brightness, focus settings to make the screen somewhat more readable.

BEFORE:

AFTER:

If we want to send the thing in for service to fix the wonkyness, we should probably hold on to the old CRT because they will probably replace the whole screen assembly and we'll lose our white screen.

In order to better understand how the composite signal would behave in the presence of noise, I decided to do a simple analysis of the cavity signals while sweeping through resonance.

My noise model was to just assume that a given signal has some rms uncertainty (error bars) and use linear error propagation to propagate from simple signals to more complicated ones.

I used the python package uncertainties to do the error propagation.

I assumed that the ALS signal, the cavity transmission, and the cavity PDH error signal all have some constant noise that is independent of the cavity detuning. Below is a sweep through resonance (x axis is cavity detuning in units of radians).

The shaded region represents the error on each signal.

Next I calculated the 'first order' calculated error signals. These being a raw PDH, normalized PDH, an inverse square root trans, and the normal ALS again. I tuned the gains so they match appropriately.

Here, one can see how the error in the trans signal propagates to the normalized and trans signals and becomes large are the fractional error in the trans signal becomes large.

Next I did some optimization of linear combinations of these signals. I told the code to maximize the total signal to noise ratio, while ensuring that the overall signal had positive gain. I did this again as a function of the cavity detuning.

Each curve represents the optimized weight of the corresponding signal as a function of detuning.

So this is roughly doing what we expect, it prefers ALS far from the resonance, and PDH close to the resonance, while smoothly moving into square root trans in the middle.

It's a little fake, but it gives us an idea of what the 'best' we can do is.

Finally I used these weights to recombine the signals into a composite, to get an idea of the noise of the overall signal. At the same time, I plot the weighting proposed by Koji's mathematica notebook (using trans and 1-trans, and a hard switch to ALS).

So as one can see, at least for the noise levels I chose, the koji weighting is not much worse than the 'optimal' weighting. While it is much simpler.

The code for all this is in the svn at 40mSVN/nicolas/workspace/2014-03-06_compositeerror

#!/bin/bash   ### this is a comment  PATH=$PATH:/home/user/path    echo "How cool is this?" 

EDIT: it looks like the code highlighting is sort of broken :-(.

 Larry and Nicolas

Larry's transfer function measurements suddenly started returning 0dB 0degrees when before there was some fake filter in the C1:ALS-OFFSETTER2 filter bank.

We looked in the filter bank and his filter was gone. So I created a new filter called LARRYP in FM2. We also disabled the output so he could drive the filter bank and test his TF code.

 Nope, we did not touch any of the PDs other than AS55. I have mentioned in  my elog:10037 what we did exactly.

We just looked at all the other PDs to check if they were being illuminated by the correctly labeled fiber. Nothing other than that.

 I suspect the integrators get fed a huge wrong signal on lockloss. Clearing the history on the trans DOFs when the MC was badly aligned gets it nicely aligned again. I switched off the alignment transmission DOFs for now.

 I don't believe it had any effect, as all the calculations gave me the same target waist.

I don't know much about how the cron job runs, I'll forward this to Max.

Max says it should be fixed now. Have the emails stopped?

Great, thanks!

I could probably install the new fan if we have one.  Can you do without the laser for a while?

Disconcerting because those tip seals were just replaced [15417]. Maybe they were just defective, but if there is a more serious problem with the pump, there is a spare Varian roughing pump (the old TP2 dry pump) sitting at the X-end.

I reset the interlock error to unfreeze the vac controls (leaving V5 closed).

Yes,

For the thin optics adapter design, we want Peek 1/4-20 screw (part # 98885A131) to replace the lower back long EQ stop. On it, we will have a Peek washer (part # 93785A600) fastened between two Peek nuts (part #98886A813).

For the thick optics adapter design, we want Peek 1/4-20 screw (part # 98885A131) to replace both the upper and lower back EQ stop. On the upper stop, we need a single Peek nut (part #98886A813).

I will cure-test the Vacseal.

I handed the Peek parts we got from McMaster to Jordan for C&B.

Cron starts with only a very minimal PATH.  However, this shouldn't be an issue if you specify the full path to the commands.

The rest of the env vars should probably not be there.

Also, Zach:  using /cvs/cds is now forbidden.  We need to put this script in the right place.

There is a package that provides the mex source, but it doesn't actually provide the mex binaries.  The problem is that the binary depends on the matlab version, so you can't possibly provide binaries for every version.

The solution is to just build the binaries from the source package.  We should put together a nice script that builds the binaries from the source, and installs them in the directory of your choosing.  If we get something nice working, we can probably get them to include it with the package, to make it easier in the future.

Here's what's included in the source package:

controls@pianosa:~ 0$ sudo apt-get install nds2-client-matlab
...
controls@pianosa:~ 0$ dpkg -L nds2-client-matlab | sort
/.
/usr
/usr/share
/usr/share/doc
/usr/share/doc/nds2-client-matlab
/usr/share/doc/nds2-client-matlab/changelog.Debian.gz
/usr/share/doc/nds2-client-matlab/changelog.gz
/usr/share/doc/nds2-client-matlab/copyright
/usr/share/matlab
/usr/share/matlab/NDS2_GetChannels.m
/usr/share/matlab/NDS2_GetData.m
/usr/share/matlab/NDS_GetChannels.m
/usr/share/matlab/NDS_GetData.m
/usr/share/matlab/NDS_GetMinuteTrend.m
/usr/share/matlab/NDS_GetSecondTrend.m
/usr/share/matlab/src
/usr/share/matlab/src/NDS2_GetChannels.c
/usr/share/matlab/src/NDS2_GetData.c
/usr/share/matlab/src/NDS_GetChannels.c
/usr/share/matlab/src/NDS_GetData.c
/usr/share/matlab/src/nds_mex_utils.c
/usr/share/matlab/src/nds_mex_utils.h
controls@pianosa:~ 0$ 

  It's a very good plan to always inspect the exit code of your command.  Well done.

I restarted the LSC models in the usual way via the c1lsc reboot script. After doing this I was able to lock the YARM configuration for more noise coupling scripting.

DASWG is not what we want to use for config; we should use the K. Thorne LLO instructions, like I did for ROSSA.

I found them, thanks. After c1psl, there are 4 2GB DIMM cards and 1 SSD left. I moved them into the storage bins with all the other Acromag parts.

You're right. We had the right idea before but we got confused about this issue. I changed all the XT1121s to XT1111 and vice versa. We already know which channels are sourcing and which not. Updated the wiring spreadsheet. The chassis seems to work. It's time to pass it over to Chub.

that little PD in the black mount was never very good. The AD829 is not a good opamp for transimpedance and especially not good for low frequencies. Stefan Ballmer and I were able to get 2e-8 out of these (@100 Hz) many years ago.

I wonder if we have some of Zach's M2ISS photodetectors around, perhaps in QIL or Cryo. I doubt that any of them are in use now. Those had good performance nad BNC output.

I worked a bit on the PSL table today

 maybe the tantalum caps on the daughter board power supply lines are blown? If so, replace with 35V+ ceramic.

I assume this QPD set is a D1600079/D1600273 combo.

How much was the SUM output during the measurement? Also how much were the beam radii of this beam (from the error func fittings)?
Then the calibration [V/m] is going to be the linear/inv-linear function of the incident power and the beam radus.

You mean the linear range is +/-50mV (for a given beam), I guess.

[gautam, paco]

Gautam managed to lock PRFPMI a little before ~ 22:00 local time. The ALS to RF handoff logic was found to be repeatable, which enabled us to lock a total of 4 times this evening. Under this nominal state, we can work on PRFPMI to narrow down less known issues and carry out systematic optimization. The second time we achieved lock, we ran sensing lines before entering the ASC stage (which we knew would destroy the lock), and offline analysis of the sensing matrix is pending (gpstime = 1310792709 + 5 min).

Things to note:

(a) there is an unexpected offset suggesting that the ALS and RF disagreed on what the lock setpoint should be, and it is still unclear where the offset is coming from.

(b) the first time the lock was reached, the ASC up stage destroyed it, suggesting these loops need some care (we were able to engage the ASC loops at low gains (0.2 instead of 1) but as soon as we enabled some integrators this consistently destroyed the lock

(c) gautam had (burt) restored to the settings from back in March when the PRFPMI was last locked, suggesting there was a small but somehow significant difference in the IFO that helped today relative to last week

Take home message--> The mere fact that we were able to lock PRFPMI rules out the considerably more serious problems with the signal chain electronics or processing. This should also be a good starting point for further debugging and optimization.

gautam: the circulating power, when the ASC was tweaked, hit 400 (normalized to single arm locked with a misaligned PRM) suggesting a recycling gain of 22.5, and an average arm loss of ~30ppm round trip (assuming 2% loss in the PRC). 

[ian, anchal, paco]

We hooked up the infrasensing unit to power and changed its default IP address from 192.168.11.160 (factory default) to 192.168.113.240 in the martian network. The sensor is online with user controls and the usual password for most workstations in that IP address.

Attachment 1 shows a five and a half day minute-trend of the three temperature sensors. Logging started last Thursday ~ 2 pm when all sensors were finally deployed. While it appears that there is a 7 degree gradient along the XARM it seems like the "vertex" (more like ITMX) sensor was just placed on top of a network switch (which feels lukewarm to the touch) so this needs to be fixed. A similar situation is observed in the ETMY sensor. I shall do this later today.

Done. The temperature reading should now be more independent from nearby instruments.

Wed Aug 11 09:34:10 2021 I updated the plot with the full trend before and after rearranging the sensors.

grecord(calc, "C1:PSL-FSS_LOCALC")
{
        field(INPA,"C1:PSL-FSS_LODET")
        field(SCAN,".1 second")
        field(PREC,"4")
        field(CALC,"6.29*LOGE(A)+5.36")
}

Yoichi, Peter

While continuing our efforts to lock, we noticed the procedure failed at a point it had gotten past last night:  turning on the bounce/roll filters in MICH, PRC, and SRC.  We checked the MICH transfer function and noticed that the unity gain point was ~10 Hz, well below the bounce modes.   We tried increasing the gain but found saturation, and Rob suggested that there could be misalignment on the AP table, which Steve worked on today.  We went out and found two of the PDs (ASDD133 and AS166) to be badly misaligned probably due to a bumped optic upstream.  We re-aligned.

Yoichi, Pete

We ran cable from the suspension rack to the IOO rack to record the signals with DAQ channels.

The test channels:

UL coil      C1:IOO-MC_DRUM1  (Caryn was using, we will replace when we are done)

UL input   C1:IOO-MC_TMP1 (Caryn was using, we will replace when we are done)

LR coil      C1:PEM-OSA_SPTEMP

LR input   C1:PEM-OSA_APTEMP

We will leave these overnight; we intend to remove them tomorrow or Monday.

We closed the PSL shutter and killed the MC autolocker.

Pete, Yoichi

Last night, we put the IFO in FP Michelson configuration.  We took transfer functions of CARM and DARM, first using CM excitations directly on the ETMs, and then using modulations of the laser frequency via MC excitation.  We found that there was basically no coupling into DARM using the MC excitation, but that there was coherence in DARM using the ETM excitation.  Therefore, I tuned the ETM common mode in the output matrix.  I did this by taking transfer functions of PD1_Q with PD2_I (see attached plot).  I changed the  drdown_bang script to set C1:LSC-BTMTRX_14 0.98 and C1:LSC-BTMTRX_24 1.02.

yoichi, pete

We installed the watchLockLoss script in scripts/AutoDTT/.  This script monitors arm power and uses command line
DTT to save 5 s snapshot of the interferometer when it senses loss of lock.  We ran it on linux and it seemed to
save an xml file about half the time; we'll try it on solaris.  

I managed to get up to arm power of about 20 a couple of times.  IFO lost lock a couple of times after turning
off moving zero.  MC2 would often get tripped by lock loss and need resetting.  Maybe we will try to stiffen the
op levs.

At about 1am or so Yoichi and I opened VC1.  CC1 had fallen to about 5e-5 torr.

I've plotted TRX, TRY, PD12I and PD11Q.  Arm powers after locking increase for a few tens of minutes, peak out, and then decrease before lock is lost.

 I should have mentioned that the AS port camera image seems to get progressively uglier over the course of these locks.  Maybe we can use the JoeCam to make a movie of it. 

locks last for about an hour.  this was true last night as well (see "arm power curve" entries).   the second lock shown here evolves differently for unknown reasons.  the jumps in the arm powers of the first lock are due to turning on DC readout.  length-to-angle needs tuning.

the align script was run after the third lock here.  it would have been interesting to see the arm powers in a 4th lock