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  40m Log, Page 287 of 339  Not logged in ELOG logo
ID Date Authorup Type Category Subject
  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.

  6085   Thu Dec 8 00:18:38 2011 ranaSummaryComputer Scripts / ProgramsBURT restore problems / issues in snapshot scripts

I tried to run the seismic StripTool tonight, which seems liek a simple task. But instead I fell through the rabbit hole again...

The seismic.stp couldn't be run from zita/op340m because zita doesn't have EPICS or MEDM and because the op340m version of StripTool cannot load the new file format in which rossa/pianosa save their files.

Once I got it running by sshing in to rossa, I noticed that the BLRMS trends didn't make any sense. Correctly guessed that this was because all of the BP and LP filters were off. Why? Because of bad BURT, that's why.

As it turns out (if you look through the autoburt logs), several of our FE machines haven't been correctly saving snapshots because of some channel count mismatch between old and new SNAP files. So we are not getting the settings restored correctly for these systems when they get booted. Probably, someone has got to suss out the source of the BURT snap messages; it may be that we have to rehash the snap process after any substantial model rebuild.

For c1pemepics, I did a manual restore from the time when Mirko last ELOG'd that BLRMS was trending OK (Nov 23 @ 3 AM).

Seems like we should also get some kind of auto email warning if the BURTs fail in this way. Otherwise, we'll lose a lot of work if it goes on for weeks.

Bottom line: fix the autoburt so that it doesn't fail after model rebuilds.

  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?

  6142   Wed Dec 21 14:23:08 2011 ranaConfigurationSUSHysteresis in suspensions?

While discussing the suspension hysteresis measurements, Koji, Kiwamu, and I realized that the suspension wire standoff is aluminum, whereas the standoff for the LIGO LOS are using quartz.

Using a soft aluminum standoff is bad. The movement of the suspension will slowly wear the groove and produce opportunities for mechanical upconversion and hysteresis.

In fact, the wire standoff as well as the clamping block on the top should be made of sapphire or ruby to prevent any such wearing issues. Steve is hot on the case.


  6148   Fri Dec 23 15:55:12 2011 ranaSummaryComputer Scripts / ProgramsCONLOG: not working since Oct 1

Often people say "I don't use conlog because its real slow". Its a little like not driving because your car has no gas.

I looked into what's going on with conlog. No one has fixed its channel list in ~1 year so it didn't make much sense. Also since Oct 1 of this year, it expired the leap seconds epoch and has been waiting for someone to look at the log file and update the list of leap seconds.

Some issues:

  • Don't use the phrases like OUTPUT, OUTMON, OUT16, or INMON as the usual part of a channel name. These are filter modules words which use to exclude channels from conlog. Please fix ALL of the LOCKIN screens to get rid of the OUTPUT filter banks.
  • If you use an EPICS channel in a servo so that its getting changed 16 times a second, make sure to add it to the conlog exclude list.

There are a bunch of bad channels which are screwing up various tools (DV, DTT, etc.):

Examples: C1:LSC-Subsystem_NPRO_SW1, C1:-DOF2PD_MTRX_0_0_SW1, C1:BAD-BAR_CRAZY_2_RSET, C1:C1L-DOF2PD_MTRX_3_14_SW2, C1:DUB-SEIS_GUR2_Z_LIMIT, etc.

  • There are a bunch of old, unused directories in c1/medm/. EVERYONE take a look in there and delete the OLD dead ones so that we don't keep recording those channels.

 To fix up some of these issues, I have deleted several MEDM directories which I thought were old (there are several extras left from Aidan's Green time). I also have put a bunch of exclude variables into the conlog 'scan_adls' script to prevent it from adding some of the new worthless channels. Finally, I have started this command

../bin/strip_out_channels '.*STAT.*','.*_ALIVE.*','C1:PEM.*','.*_Name.*','C1:UCT.*','C1:MCP.*','C1:SP.*','C1:DU.*','C1:RF.*','C1:NIO.*','C1:TST.*','C1:SUP.*','C1:X.*','C1:FEC.*','.*_LFSERVO.*','.*FSS_SLOWDC.*','C1:LSC-LA_MTRX_21','C1:LSC-PD.*OFFSET','C1:LSC-ETM.*OFFSET' conlog*.log

which should strip lots of the excess conlog data out of the conlog directory. The only downside is that its setting all of the timestamps of the .log files to today instead of the historical times but I don't think we'll care about this too much. Hopefully it will speed things up to have less than 450 GB of conlog files...

update: 12 hours later, its still running and has removed ~100 GB so far. It will probably take the rest of the weekend to finish.

  6165   Wed Jan 4 02:43:40 2012 ranaUpdateGeneralActuators for Stewart platform


 I checked on the two single-axis shakers that are present at the 40m that Steve pointed out:

  • Brüel & Kjær type 4809, rated for 45 N peak, and
  • Brüel & Kjær type 4810, rated for 10 N peak.

Neither of these meet the force requirement of 2.04 kN peak.

 Time to lower your expectations!

Do we really need 40 microns at 500 Hz? Or perhaps should there be a frequency dependent displacement requirement?

  6179   Fri Jan 6 20:10:48 2012 ranaUpdateCDSframebuilder back online, using NTP time syncronization


 You (Jamie) should talk with Rolf and Alex to find out what framebuilder they will support for > 3 years. Then we should buy that along with the adapter card which allows us to use the same RAID we now have for the frames.

  6208   Tue Jan 17 19:07:47 2012 ranaUpdateLSCglitch hunting in REFL RFPDs : strange

 Another possibility is that there is some beam clipping of the REFL beam before it gets to the PD. Then there could be a partial reflection from that creating a spurious interference. Then it would only show the fringe wrapping if you excite the scatterer or the PRM.

  6216   Fri Jan 20 17:05:59 2012 ranaUpdateGreen LockingY arm ALS : time series

                        One of my goals this week is to get people to make plots with physical units:

That ALS plot would be 5x cooler if the POY11 signal could be in meters instead of counts or cubits.

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

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

is this the normal state? Screenshot attached.

Attachment 1: mctrans.png
  6252   Fri Feb 3 19:57:26 2012 ranaConfigurationSUSPSL Shutter closed for SUS hysteresis test

Fri Feb 03 19:57:20 2012

Fri Feb 03 20:25:19 2012 :   Aligned all SUS to center their OL beams

Fri Feb 03 20:29:21 2012:    Aligned all SUS to make OL_PIT = 0.5

  6253   Fri Feb 3 20:19:38 2012 ranaUpdateSUSOplev QPD Sum Trends are suspicious

The attached trend shows a problem with the QPD sums.

Why are ETMX and ITMX so much lower than ETMY and ITMY? Are the laser's dying? Or is it the gain inside the QPD? Or the reflectivity of the coatings?

Steve - please check on Monday the laser powers and the ETM/ITM reflectivity for HeNe lasers. Maybe we have to increase the transimpedance gain in the heads.

Attachment 1: a.png
  6265   Thu Feb 9 20:01:02 2012 ranaSummaryElectronicsUsing RF LP filters as dispersion units for the MFD

 WE currently use long cables to give us the dispersion that we want for the MFD. A cable gives a long delay - both the phase delay and the group delay.

But we only need the dispersion (group delay). We can get this by just using a very sharp low pass filter and having the corner be above the frequency that we have the beat signal.

For example, the MiniCircuits SLP-200+ has got a corner frequency of 200 MHz and a group delay of ~10 ns (like a 3 m vacuum delay). So we would have to use 10 of these to get the delay we now get. The passband attenuation is only 0.5 dB, so we would lose 5 dB. The cost is $35 ea. We have a few on the shelf.

OTOH, if we tune the beat frequency down to 30 MHz, we can use the SLP-30 which has a group delay of 30 ns around 30 MHz. That's like 9m at light speed. We could easily get a nice result by just using 4 or 5 SLP in series.

So why is Kiwamu using cables?? And how should we really choose the beat note frequency??

  6271   Fri Feb 10 15:47:38 2012 ranaUpdatePEMseismic noise back to normal


 Kiwamu and Steve maybe don't know about how to trend seismic noise. If you just take the mean of the time series, you don't prove that the seismic noise got any higher. The STS has a nominally zero DC output, so the long period level shifts that you see tell you just that there was a DC offset.

This is NOT an increase in seismic noise. To see a seismic trend you should plot the trend of the BLRMS channels that we made especially for this purpose.

  6275   Fri Feb 10 23:58:30 2012 ranaUpdatePEMseismic BLRMS loud too



 So, none of our PEM BLRMS channels are recorded as of right now.  All we have for long-term record is the StripTool on the wall.  The 0.1-0.3Hz and 0.3-1 Hz traces both show these weirdo things, but the 1Hz and up BLRMS don't have any unusual noise.

 Seems like a problem to solve on Monday so that we don't end up without trends like this again.

  6289   Thu Feb 16 13:12:30 2012 ranaUpdateLSCsensing matrix of PRMI


I think I have told a lie in the last meeting -- the measured sensing matrix doesn't look similar to what Optickle predicts.

Smells like something is very wrong.

 Those Radar plots are awesome. Even more awesome would be if they were in units of W/m (so that it can be directly compared with Optickle) and so that the numbers are useful even 1 year from now. Otherwise, we will lose the RF transimpedance information and thereby lose everything.

Also, please post the provenance of the counts->V calibration.

  6315   Fri Feb 24 18:37:13 2012 ranaUpdateLSCY arm + PRMI part II


I tried the Yarm + PRMI configuration again.

The PRMI part was locked, but it didn't stay locked during the Y arm was brought to the resonance point.


 Isn't the point that the 11 and 55 MHz signals have the carrier effect, but the 3f signals are better?

  6335   Tue Feb 28 16:44:56 2012 ranaUpdateLSCMICH and PRCL signals in a simulation


 Like I said, this is possible if you fail to set up the OSA to look at the sidebands at BOTH the AS and REFL ports at all times. Don't waste your time - set up an OSA permanently!

  6367   Tue Mar 6 23:14:38 2012 ranaUpdateSUSOptical Lever had bad filters

 We found that that bounce (16.1 Hz) and roll (23.5 Hz) modes on the ITMX were much higher than on the ITMY. After some checking, it seems that the bandstop filters for the

SUSPOS, SUSPIT, SUSYAW, and SUSSIDE loops are set to the correct frequencies. However, the OLPIT and OLYAW had not been set correctly. I have copied the SUS filters into the OL filterbanks and reloaded all the filter banks. Attached are the comparison of old, bad, OL with the SUS ones.

The same cockamamie situation was there for the BS & ITMY as well. Although we still don't have the roll mode frequencies listed in the mechanical resonances wiki, I have guessed that the ITMY roll frequency is the same as the ITMX, since they have nearly the same bounce frequency. OL filters for the BS & ITMY are now at the right frequency (probably). Keiko is on top of fixing things for the other optics.

I think this whole notching adventure was in Leo's hands several months ago, but WE forgot to point him at the OLs in addition to the SUS. I blame Kiwamu 50% for not supervising him and Koji by 45% for not supervising Kiwamu. The other 5% goes to someone else. You know who you are.

Attachment 1: Untitled.png
  6381   Wed Mar 7 21:13:30 2012 ranaUpdateDAQNDS2

 I noticed that NDS2 was not running on mafalda as it should be. Instead, there were a couple of zombie MEDMs using up 99% of the CPU. I killed the zombies and have run the 'build channel list' script. When it finished, I tried to restart the nds server, but got the following error in the log file. Email has been dispatched to JZ.

mafalda:logs>less nds2-mafalda-201203072111.log

Configuring from file: nds2.conf
Allow list: ALL
terminate called after throwing an instance of 'std::runtime_error'
  what():  Insufficient arguments
  6425   Fri Mar 16 16:01:53 2012 ranaUpdateElectronicsREFL165 calibration : measurements

 To characterize the RF V to counts we need to know the state of the whitening filter board. Was the filter on or off ? What was the value of the whitening gain slider?

  6442   Sun Mar 25 20:13:31 2012 ranaHowToSUSOptical Lever Servo Tuning thoughts

To start the optical lever filter design, I looked into the noise on ITMY. It should be similar to the other arm cavity optics since they have the same whitening electronics.

The RED/BLUE are with loops open. The MAGENTA/CYAN with loops closed. Looks good; the bandwidth is a few Hz and there is not much peaking,

To figure out the contribution from the dark noise I misaligned the ITMY until the sum on the QPD went to zero. Then I took the spectra of the OL{1,2,3,4}_OUT signals (they all looked the same).

To normalize them properly I took OL4, multiplied it by 2 to account for the incoherent sum of 4 channels and then divided by the nominal SUM (which was 14685 counts). I've left the OL3 un-normalized to show the ratio.

From this plot it seems that the dark noise is not a problem at any frequency (no need to amplify for the new ADCs).

I'm going to use the open loop spectra to design the optimal feedback control. The file is saved as /users/rana/dtt/ITMY_OL-120325.xml

Attachment 1: Untitled.png
  6463   Wed Mar 28 21:15:53 2012 ranaOmnistructureComputersWireless router for GC

I installed a NETGEAR Wireless Router (WPN824N) today on the 131 network. The admin password for it as well as the wireless access password are in the usual places.

The SSID is 40EARTH. I have set it to allow WPA as well as WPA2 access, so the speed is only 54 Mbps for now. In a year or so, we can turn off the WPA support and up the speed.

  6517   Tue Apr 10 23:56:44 2012 ranaUpdateComputersSensoray

Now that Mike has got the Sensoray working, Jenne/Suresh should grab some new images of the ETM cage as Keiko did so that we can analyze them for another mode matching diagnostic.

  6523   Wed Apr 11 22:48:39 2012 ranaUpdateEnvironmentBLRMS


  6567   Wed Apr 25 18:59:47 2012 ranaUpdatePEMBlue Bird Pre-Amplifier

Usually R is for resistors and D is for diodes. Do you think from the schematic that we should put diodes into the R slots?

  6585   Mon Apr 30 18:46:34 2012 ranaUpdateComputersmegatron

Last week I found that megatron was still off after the power outage. Apparently, the power recovery checklist had not been followed during the recovery.

Please remember to use the checklist and post the checklist results after each power outage. Megatron is now on and functioning.

  6694   Sun May 27 17:19:27 2012 ranaSummaryloreStrawberries

 We have placed some sweet giant strawberries in the fridge; free for eating for anyone working in the lab today or tomorrow:


  6719   Wed May 30 20:12:15 2012 ranaUpdateIOOMC beam spot oscillation

This is a common occurrence when diagnostic scripts are written without the ability to handle exceptions (e.g. ctrl-c, terminal gets closed, etc.).

The first thing to do is make sure that the "new" script you are writing doesn't already exist (hint: look in the old scripts directory).

If you are writing a script that touches things in the interferometer, it must always return the settings to the initial state on abnormal termination:


  6745   Fri Jun 1 19:48:54 2012 ranaUpdateSUSOplevs all different, messed up


 Its a good question, but the answer is yes. At some level all of the OL servos should be different to handle the different mechanical resonances of the suspension as well as the optical table's acoustic noise and the different noise requirements for the difference optical cavities.

However, it would be better to have the same basic structure and then one or two customization filters.

  6785   Thu Jun 7 13:18:42 2012 ranaUpdateSUSPRM is still oscillating

  Set the PRM OL servo gains to zero until someone can take care of this. Turning off the buttons doesn't help anything if people run the alignment scripts.

  6811   Wed Jun 13 02:24:02 2012 ranaUpdateGreen Lockingmy first modescan (sort of)

 That sounds goofy.

With the delay line technique, you can get a linear signal over 50 MHz with no phase shifting. What is with all this I/Q stuff?

  6813   Wed Jun 13 11:10:56 2012 ranaUpdateGreen Lockingmy first modescan (sort of)

You can easily calculate whether or not the coarse readout will work by thinking about the scan resolution you need given the ADC dynamic range and the whitening filter that you use.

  6839   Wed Jun 20 18:00:10 2012 ranaSummaryPSLsummaries

 Nice PSL summaries from LHO:


  6877   Wed Jun 27 10:27:09 2012 ranaSummaryIOOhow to improve mode matching to arms

The MC waist is correct as is the arm RoCs. Most likely the error is in the telescope length or its distance from the MC. Jenne probably has all the numbers and can give us a surface plot showing how the MM degrades as a function of those two parameters.

  6888   Thu Jun 28 15:21:02 2012 ranaUpdateLockingPRMI work started, commissioning plan


 Cycling the vacuum is easy. Why not vent starting Thursday evening and pop the doors on Friday morning? Inspect on Friday and pump on Monday morning.

  6901   Mon Jul 2 00:41:13 2012 ranaSummaryGeneralclipping at BS, my plan


 Start pumping on Monday before Steve goes home.

  6976   Sun Jul 15 16:25:15 2012 ranaUpdateLSCPRMI LSC is making PRM motion worse

As stephanie did a few years ago, the idea should be to match the damping between the DRMI optics so as to minimize the differential motion. No notching is necessary. Read her SURF report about the IMC.


  6993   Thu Jul 19 15:55:21 2012 ranaUpdateComputersused 'aptitude' to install software (TexLive) on rosalba

I used APTITUDE to install texlive-full on rosalba so that I could work on a paper. pdflatex was not found on pianosa, rosalba, megatron, etc. I used this command:

sudo aptitude install texlive-full

While this was installing, I read a bunch of forums which claim that its better to bypass the apt-get and use the 
TexLive installer instead so that we can use its own package updater 'tlmgr'. Otherwise, the standard Ubuntu distributions
are years out of date (e.g. doesn't have RevTex 4.1).

  6994   Fri Jul 20 11:59:27 2012 ranaUpdateComputer Scripts / ProgramsCONLOG not running

WE tried to use the new conlog today and discovered that:

1) No one at the 40m uses conlog because they don't know that it ever ran and don't know how to use regexp.

2) It has not been running since the last time Megatron was rebooted (probably a power outage).

3) We could not get it to run using the instructions that Syracuse left in our wiki.

Emails are flying.

  6995   Fri Jul 20 12:12:25 2012 ranaUpdatePSLPMC problems examined

Jenne, Den, Rana

The PMC transmission has been varying a lot and the MC seems unstable. Superstitious people might blame this on the El-nino or the alignment with Sagitarius, but we are ostensibly scientists.

WE found that the PMC EPICS values had not been toggled since the reboot and so the RF phase and Amplitude were totally wrong (we should replace this with a fixed oscillator box as we did with FSS).

Also, the NPRO SLOW slider was at -2 V which made the mode going into the PMC funny (although the mode was OK this morning before I started playing with the PMC sliders).

Before adjustment, there was a strong correlation between the seismic motions and the PMC reflection. This means that the PMC gain was low and it couldn't stay locked. Now, after fixing the RF and upping the gain slider it looks more stable. Let's watch it for a few days to see if there's an improvement in the trends.

The 10-minute trend of the lat 400 days shows that nothing has changed much this year; its been equally bad for a long while.

Attachment 1: Untitled.png
  7015   Mon Jul 23 21:54:48 2012 ranaUpdatePEMWeather Station Works!

To get the code to run on c1pem1, we had to move the old target back into the /cvs/cds/caltech/target/ directory.  It is in /cvs/cds/caltech/target/c1pem1/.

JoeB had apparently moved it into some other area called 'oldfe' and this was why the weather station has not been running for years.    Joe is at LLO now, but he's not beyond our reach...

Once the code had been moved back I started it up. I also rebooted it from the telnet prompt to ensure that it worked on reboot. It did.

The cable issue that Liz mentions probably happened during the PSL table lifting and cable cleanup. It looks like someone yanked the ethernet cable out of its adapter and broke it...

Attachment 1: Untitled.png
  7034   Wed Jul 25 23:03:22 2012 ranaUpdatedigital noisenotch, lowpass filters

If the problem is the precision in DTT, then why would the noise change when the corner frequency of the filter is changed?

And how about checking for filter noise in the situation we saw online? 4th order low pass at 1 Hz or 8 Hz.

  7039   Thu Jul 26 15:43:03 2012 ranaUpdateLSCmodelled ringdown

You cannot use the digital system for this. You hook up a scope to the transmitted light as well as the incoming light (after the MC, perhaps at IP_POS). Then you acquire the data from both places simultaneously using an ethernet equipped scope. The step response of the PDs used for this has to be calibrated separately.

  7107   Tue Aug 7 16:21:16 2012 ranaUpdateSUSoptical table box wall proposal


 Sanwiched wall as shown: 1" clear acrylic, 2 layers of 0.004" thick "window tint", 1 layer of  0.007" thermashield and  0.125" yellow acrylic

Visibility: 70 %,    Transmission of 1064 nm  2-3 % at 0-50 degrees incident  power density 0.7 W/mm2

Max power 100 mW        

 Good. The power density and max power are not important (especially since you don't define a quantitative way to spec them). We ONLY care about the transmission.

  7110   Tue Aug 7 23:30:58 2012 ranaUpdateEnvironmentNearby EQ

 Just felt an EQ. Impulse moved some vertical blinds by several mm.

Tue Aug 07 23:26:06 2012 

  7112   Tue Aug 7 23:33:44 2012 ranaUpdateSTACISMore noise data

Looks like you're just measuring the ADC noise. You should add ADC noise to your plot. To compare the geophones with the accelerometers, you have to correct for the preamp gain and plot them both in the same units.

To get above the ADC noise you can use an SR560 preamp. (AC Coupled, G = 100)

  7126   Wed Aug 8 22:12:30 2012 ranaConfigurationIOOMC trans optics configured

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

  7183   Tue Aug 14 21:01:51 2012 ranaUpdatePEMBLRMS


I fixed up the seismic.stp file for the StripTool display:

  1. All BLRMS channels now have a y-axis range of 3 decades. So they all are displaying the same relative changes.
  2. So the 0.01-0.1 Hz band which is all over the place is real, sort of. Masha says that it is due to the seismometer signal being dominated by noise below 0.1 Hz. She is going to fix this somehow.
  3. I changed the samping time from 1 sec. to 10 sec. to make the traces less fuzzy.
  4. We (Masha / Liz) should harmonize the colors of this file with what's on the summary pages.
  7187   Wed Aug 15 04:03:55 2012 ranaSummaryLSCY-Arm Locking

0) Did a bunch of alignment to get beams roughly centered on ETMY and ITMY and maximize power. Adjusted the aperture and focus on ETMY camera to get nice image. Camera needs to be screwed in tightly and cables given some real strain relief, Steve.

1) snapshots not working on many MEDM screens. Who's on top of this?

2) save/restore not working for PZT2 sliders

3) changed power and filter triggers on yarm to match xarm

4) yarm filters copied from xarm (need to handtune RGs)

5) DTT wasn't working on rossa. Used the Date/Time GUI to reset the system time to match fb and then it stopped giving 'Test Timed Out'. Jamie check rossa ntpd.

6) Removed the high 3.2 Hz RG filter. We don't have any sharp features like that in the spectrum.
   ---then added it back. The 3.2 Hz comes and goes depending on what Yoichi is doing over in the MC area. Leaving it in by default, but lowering the Q from 2 to 1.5.

7) Attached is the noise spectra, coherence, and loop gain model for this yarm condition. For the plant model, I assume a pendulum (f=1 Hz, Q = 9) and a cavity pole of 1600 Hz. Gain is scaled to set the UGF at 165 Hz (as guessed by looking at the servo gain peaking frequency). This cheezy model doesn't include any of the delays from DAC, AA, or AI. Eric and Sasha should have something more useful for us by Friday.

8) Change the DQ channels: need XARM and YARM IN1 at 16k. e.g. XARM_ERR, etc.

9) To get the DTT plots to make thumbnails in the elog, I print a .ps file and then use 'epstopdf' to make the PDF.

Attachment 1: yArmNoise_120815.png
Attachment 2: yarm.pdf
ELOG V3.1.3-