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ID Date Authordown Type Category Subject
  3413   Thu Aug 12 17:28:28 2010 RazibUpdatePhase CameraSideband power measurement (updated)


This sounds very relieving although this could be a lower bound of the number.
Why didn't you use the output on the PD which just give us the direct observation of your so-called SCR.


So the SCR is calculated by the ratio of the FFT'd DC and the 5 Hz signal. Using the CCD, I obtained the SCR to be 0.075 ± 0.01. Previously, we expected our SCR to be 0.09 as in the previous e-log entry. 


 The SCR was at first measured using the output of the PD. That was exactly from where we got our 0.09 (previous elog entry). The second measurement was from the CCD.

  2465   Tue Dec 29 13:57:20 2009 Rana, Kiwamu, and HaixingUpdatePhotosPhotos of video switch box

Before we installed the video switch box, we also took some photos of it. We uploaded them onto the 40m Picasa.

Video Matrix

The first photo is the an entire view of the switch box. The following four photos are the details of the switch matrix.

 The slideshow below is a dump of the last several months of photos from the Olympus. The originals have been deleted.

  8387   Tue Apr 2 10:22:37 2013 Rana, Gabriele, JenneUpdateLSCPRMI lock

We locked the PRMI, this time really on the sidebands, using the two REFL55 signals.

Here are the parameters: triggering on POP22_I in at 140, out at 20. No normalization. MICH gain -0.15, PRCL gain 0.1

It seems that the lock is not very stable. It seems likely to come from some large angular motion of one of the mirrors. We'll need to calibrate the optical lever signals to understand which one is moving too much.


Attachment 1: lock_prmi_sb.pdf
  8776   Thu Jun 27 22:52:38 2013 Rana, Gabriele, FrancescoSummaryComputer Scripts / ProgramsLIGO-DV installed

I installed ligoDV in the /ligo/apps/ligoDV/

Now, by pointing the tool at the local NDS2 server (megatron:31200) you can access the recent local data (raw, trends, etc.)

by running /ligo/apps/ligoDV/ligodv from the command line.

Attachment 1: ldv.png
  1954   Wed Aug 26 19:58:14 2009 Rana, AlbertoUpdatePSLReference Cavity Temperature Control: MINCO PID removed

Summary: This afternoon we managed to get the temperature control of the reference cavity working again.

We bypassed the MINCO PID by connecting the temperature box error signal directly into EPICS.

We couldn't configure the PID so that it worked with the modified temperature box so we decided to just avoid using it.

Now the temperature control is done by a software servo by using the channel C1:PSL-FSS_MINCOMEAS as error signal and driving C1:PSL-FSS_TIDALSET (which we have clip-doodle wired directly to the heater input).


We 'successfully' used ezcaservo to stabilize the temperature:

ezcaservo -r C1:PSL-FSS_MINCOMEAS -s 26.6 -g -0.00003 C1:PSL-FSS_TIDALSET


We also recalibrated the channels:




with Peter King on the phone by using ezcawrite (EGUF and EGUL) but we didn't change the database yet. So please do not reboot the PSL computer until we update the database.


More details will follow.

Attachment 1: rc.png
  3241   Fri Jul 16 23:53:27 2010 RanaUpdatePSLReference Cavity Insulation

From the trend, it seems that the Reference Cavity's temperature servo is working fine with the new copper foil. I was unable to find the insulating foam anywhere, but that's OK. We'll just get Frank to make us a new insulation with his special yellow stuff.

The copper foil that Steve got is just the right thickness for making it easy to form around the vacuum can, but we just have to have the patience to wrap ~5-10 more layers on there. We also have to get a new heater jacket; this one barely fits around the outside of the copper wrap. The one we have now seems to have a good heating wire pattern, but I don't know where we can buy these.

I also turned the HEPA's Variac back down to the nominal value of 20. Please remember to turn it back up to 100 before working on the PSL.

  3280   Fri Jul 23 16:02:16 2010 RanaUpdatePSLReference Cavity Insulation

This is the trend so far with the copper foil wrapping. According to Megan's calculation, we need ~1 mm of foil and the thickness of each layer is 0.002" (1/20th of a mm), so we need ~20 layers. We have ~5 layers so far.

As you can see the out-of-loop temperature sensor (RCTEMP) is much better than before. We need another week to tell how well the frequency is doing -

the recent spate of power cycles / reboots of the PSL have interrupted the trend smoothness so far.

Attachment 1: Untitled.png
  3282   Fri Jul 23 21:14:29 2010 RanaUpdatePSLReference Cavity Insulation

I wrapped another ~3 layers onto there. It occurs to me now that we could just get some 2mm thick copper plates made to fit over the stainless steel can.

They don't have to completely cover it, just mostly. I also took the copper circles that Steve had made and marked them with the correct beam height

and put them on Steve's desk. We need a 1" dia. hole cut into these on Monday.

To compensate for the cooling during my work, I've set the heater for max heating for 1 hour and then to engage the temperature servo.

I also noticed the HEPA VARIAC on the PSL was set to 100. Please set it back to 20 after completing your PSL work so that it doesn't disturb the RC temperature..

  7869   Fri Dec 21 16:50:30 2012 RanaUpdateSUSTT in vac DB25 pin swapping

[Koji, Rana, Nic, Steve]

We went to the 25-pin D cable which connects to the TT1 quadropus and succeeded eventually in swapping pins 12/24 into the 13/25 positions.

  1. The D-sub connector is a custom made LIGO part and so it doesn't at all work to use the standard pin extractor tools to move the pins out; we should have investigated this before spending all this time poking at and possibly damaging the existing connector.
  2. To move the pins, we have to partially dis-assemble the connector and fish the pins/wires through the appropriate holes. Unfortunately, the design is such that we nearly lose all of the pins when trying to do this. Pictures describe the story better than words.
  3. After the swap we tried to test the TT, but again wasted some time because the vac feedthrough was incorrectly labeled. The 25-pin feedthrough labeled as "PZT1" does not, in fact, connect to the TT. Instead, its the one slightly above it that is labeled "Pico". I have moved the PZT1 sticker up to match the actual connector. In order to discover this, we beeped through several stages of the coil driver, cable system. WE need to order some in-line D-sub breakouts for 25pin, 37pin, and 9pin which are similar to the ones we have now for 15pin. These are better than the green terminal block breakouts.
  4. After this, we were able to see the TT move, but elected to leave the final piece of the work (determining which microD goes with which coil) to when Jamie gets back.
  5. The TT screen is not good: it needs to be just like the usual sus screen so that we can put in offsets, excitations, etc. Perhaps also the ASC-TT screen can link to the TT:SUS screens. We can just copy the eLIGO TT screens to get going.
  8395   Tue Apr 2 21:11:42 2013 RanaUpdateoptical tablesOptical Table Toolboxes Update


A heavy duty plastic box is the likeliest candidate for the optical table toolbox. It measures 5 9/16 in. x 11 5/8 in. x 4 5/8 in. and fits all the tools comfortably. ( http://www.mcmaster.com/#plastic-bin-boxes/=m4yh4m  ,  under Heavy Duty Plastic Bin Boxes)

The list of tools has been updated to include a pen and a wire cutter as well as everything previously stated.

In addition, Steve has recommended that boxes should be secured to the walls or surfaces near the optical tables as opposed to the optical tables themselves, as to keep the tables from wobbling when tools are being exchanged.

A diagram of tentative box placements will go out soon.

 No, the small boxes must be attached to the optical tables. They won't be heavy enough to change the table tilt.

Also, all tools must be color coded according to the optical table using the 3M Vinyl table color code:


  9316   Wed Oct 30 03:33:17 2013 RanaUpdateLSCLSC demod boards need some thought



I worked on the script SPAG4395A.py tonight with Masayuki's help. This sets up the parameters on the Agilent 4395A and then acquires the spectrum data. It had a couple of bugs before: no matter what channel you requested, you always got channel R. It also would disobey any requests to reduce the attenuation and left the Auto Atten ON. The version now in the SVN allows you to choose the channel and the attenuation.

It then makes this plot using matplotlib. The attached image is from the REFL165 pickoff at a time tonight when the arm powers were ~5-10. I have converted the spectrum from RF electrical Watts into Volts (V = 50*sqrt(W)). To go from the analyzer input to the demod board input we should scale this spectrum by a factor of ~15 (to account for the 20 dB from the coupler and the 3 dB of the splitter and a little more for losses). On the oscilloscope we see Vpp ~5 mV, so that's ~75 mVpp at the output of the BBPD which we're using for REFL165. Perhaps we can handle another factor of ~2-3 ? I'm not sure what we have in terms of linearity measurements on this thing.

EDIT: Evan is right, its V = sqrt(50*W), not V = 50*sqrt(W). ignore y-axis above

  16061   Wed Apr 21 11:01:37 2021 RanaUpdateCDS40m LSC simPlant model

The controller would be in the c1sus model, and connects to the c1sup plant model. So the controller doesn't go in the plant model.

Both the controller and the plant can be modeled using a single filter module in each separate model as you've drawn, but they go in separate models.


  7624   Thu Oct 25 15:38:06 2012 RajiUpdateAlignmentTransmitance Measurements on LaserOptik mirror

I measured the transmitted power @1064nm on one of the LaserOptik mirrors labled SN6

Here is the data

Polarization Input Angle Input Power(mW) Output Power(mW) Transmittance (%)
p 0 6.2 2.67 48
p 0 100 52 52
p 45 6.2 0.76 12
p 45 100 1,5 1
s 0 8.2 3.15 38
s 0 100 40 0.4
s 45 8.2 0.5 6
s 45 100 0.66 0.006

The mirror is not a good reflector at 0 deg.

  7644   Wed Oct 31 12:58:17 2012 RajiUpdateAlignmentTransmitance Measurements on LaserOptik mirror


I measured the transmitted power @1064nm on one of the LaserOptik mirrors labled SN6

Here is the data

Polarization Input Angle Input Power(mW) Output Power(mW) Transmittance (%)
p 0 6.2 2.67 48
p 0 100 52 52
p 45 6.2 0.76 12
p 45 100 1,5 1
s 0 8.2 3.15 38
s 0 100 40 0.4
s 45 8.2 0.5 6
s 45 100 0.66 0.006

The mirror is not a good reflector at 0 deg.

 More data on the transmission. Measured the tranmission as a funtion of incidence angle at 1064nm

Attachment 1: Transmission-plot@1064nm.pdf
Attachment 2: Transmission-data@1064nm.pdf
  9296   Sat Oct 26 21:46:33 2013 RANAUpdateIOOMode Cleaner Tune-UP

 The MC had been unlocked for the last 4 hours and was crying out to me so I gave it some attention. Its happier now.

From the trend (AtM #1), I saw that the MC2 suspension has moved by ~10 microradians. Since the MC cavity divergence angle is lambda/(pi*w0) ~ 200 microradians, this isn't so much, but enough to cause it to lock on bad modes sometimes. Attackmint too shows that there's not much in monotonic drift over the last 40 nights.

I moved back MC2 to its old alignment with these commands:

ezcaservo -r C1:SUS-MC2_SUSPIT_INMON -s -1017 -g 0.0009 C1:SUS-MC2_PIT_COMM -t 300

ezcaservo -r C1:SUS-MC2_SUSYAW_INMON -s 490 -g 0.0009 C1:SUS-MC2_YAW_COMM -t 332

Then I went out to the table and aligned the beam into MC using the last two steering mirrors good enough so that the WFS coming on doesn't make the visibility any better. In this nominal state, I unlocked the MC and then aligned the reflected beam onto the center of the LSC PD as well as the WFS. The beam on the first WFS is a little small - next time someone wants to improve our Gouy phase telescope, we might try to make it bigger there. On the LSC PD, the beam was off-center by a few hundred microns.

Attachment 1: MCtrend.pdf
Attachment 2: MC40days.png
  9298   Sun Oct 27 00:15:35 2013 RANAUpdateSUSc1auxex

 At some point tonight we lost our CA connection to c1auxex (which is actually the computer at the X End and controls the ETMX, but has a Y sticker). We could telnet to it, but its puny RAM must have been overloaded with too many EPICS connections that bypassed the CArepeater. I went around and booted some machines and it seems to be back and allowing damping now. Along the way I keyed off the crate to c1auxex a couple of times.

When trying to close the rack door I saw that Charlie/Steve had illegally connected the power cable for the illuminator through the door so that it couldn't close, so I disconnected it so that they can run it properly and feel better about themselves.

Disclaimer: Steve had nothing to do with this connection. I rerouted the cable the correct way. 10-28-2013

** what does this coherence tell us about the noise in the arms ?

Attachment 1: arms.pdf
Attachment 2: arm-mc2-dewhite.pdf
  9306   Mon Oct 28 21:33:55 2013 RANAUpdateIOOMode Cleaner Tune-UP


8 day minute trend of some of the IMC alignment signals.

That step ~2 days ago in the WFS2 yaw control signal shows that I didn't do such a good job on yaw.

Nic is going to come over some time and give us a new Gouy telescope that let's us have bigger beams on the WFS. At LLO, Hartmut demonstrated recently how bigger beams can reduce offsets somehow...mechanism TBD.

Also, we must angle the WFS and figure out how to dump the reflections at the same time that we rework the table for the telescope.

Steve, can you please put 2 mounted  razor dumps near the WFS for this purpose??    

            Tuesday: Razor dumps are waiting for you.


Attachment 1: Untitled.png
  9323   Thu Oct 31 20:05:48 2013 RANAUpdateIOOMode Cleaner Tune-UP


Steve, can you please put 2 mounted  razor dumps near the WFS for this purpose??    

            Tuesday: Razor dumps are waiting for you.

 I couldn't find any dumps near the WFS. Koji looked. I looked twice. Maybe they are spooky and absorbing all of the light?

The MC alignment was bad and the WFS were making it drift. Koji aligned the beam into the PMC. I then restored the MC suspensions to where they were 8 days ago (back when the transmission and reflection were good). With the WFS OFF, this gave us a MC trans ~ 16000. With WFS ON it goes to 17500 which is about as good as its been over the last 80 days.

I centered the beam on the WFS with the MC unlocked and also centered the beam on the whole WFS path (it was near clipping between WFS 1 & 2). Also for some reason that beamsplitter which steers the beam onto WFS1 is a R=33% (!? why is this not a R=50% ??).

Steve, please swap this out to a BS1-1064-50-1025-45S if we have one sitting around. If not, we want to add this to the CVI purchase list, but not buy until we get a bigger list together.

I also centered this newly aligned beam into the IMC onto the PSL QPDs. We should now use these as a pointing reference for the beam into the IMC.

While doing this I noticed that the beam was almost clipping on the Uniblitz shutter used to block the PSL beam. That shutter is mounted too short and was also not centered horizontally. I removed it for now so that Steve can find a more adjustable mount for it and put it back into play. The beam going into the IMC is BIG, so you have to very careful when centering the shutter. Might be that we cannot leave it at 45 deg and still get a big enough aperture.

Note #3 for Steve: please also replace the mount for last steering mirror into the IMC with a Polanski or a Superman, that black Ultima is no good. Also the dogs must be steel - no aluminum dogs for our sensitive places.

Attachment 1: drifty.png
  9365   Mon Nov 11 22:35:45 2013 RANAUpdateIOOPSL pointing monitoring

Since the pointing has gone bad again, I went to the PSL to investigate. Found some bad things and removed them:

1) There was a stopped down iris AGAIN in the main beam path, after the newly installed mirror mount. I opened it. Stop closing irises in the beam path.

2) The beam dump for the IOO QPD reflection was just some black aluminum. That is not a real dump. I removed it. We need two razor blade dumps for this.

3) There was an ND filter wheel (???) after one of the PMC steering mirrors. This is not good noise / optics practice. I removed it and dumped the beam in a real dump. No elog about this ?!#?


The attached trend shows the last 20 days. The big step ~2 weeks ago is when Steve replaced the steering mirror mount with the steel one. I don't understand the drift that comes after that.


Today I also spent ~1 hour repairing the Aldabella laptop. Whoever moved it from the PSL area to the SP table seems to have corrupted the disk by improper shutdown. Please stop shutting the lid and disconnecting it from the AC power unless you want to be fixing it. Its now running in some recovery mode. Lets leave it where it is next to the PSL and MC1.

I steered the MC suspensions back to where they were on the trends before the PSL mirror mount swap and then aligned the PSL beam into it by touching the last 2 steel mounts. Once the alignment was good without WFS, I centered the beams on the IOO QPDs. If it behaves good overnight, I will center the unlocked beams on the MC WFS.


Please stay off the PSL for a couple days if you can so that we can watch the drift. This means no opening the doors, turning on the lights, or heavy work around there.

Attachment 1: qpd.pdf
  9370   Tue Nov 12 23:48:23 2013 RANAUpdateIOOPSL pointing monitoring

Since I saw that the trend was good, I aligned the MC refl path to the existing IMC alignment:

  1. removed a broken IRIS that was clipping the reflected beam (and its mount)
  2. moved the first 1" diameter steering mirror on the high power path after the 2" diameter R=10% steering mirror. It was not centered.
  3. Moved the lens just upstream of the LSC RFPD away from the PD by ~5 mm. The beam going towards the WFS was too close to this mount and I could see some glow.
  4. Centered the beam on all optics in the WFS path and then the WFS DC.
  5. Centered beam on LSC RFPD.

The reflected spots from the PD are not hitting the dump correctly. WE need to machine a shorter post to lower the dump by ~1 cm to catch the beams.

  9400   Mon Nov 18 19:45:42 2013 RANAUpdateSUSPRM pictures

Nice camera work Steve! I will use these for publicity photos.

Now we need to get one of the video cameras hooked into the MUX so that we can see the flashing and do some image subtraction.

  9521   Mon Jan 6 18:32:17 2014 RANAUpdateIOOMC1/3 kicked this morning at 8:30

 The trend shows a big jolt to the MC1/3 pointing this morning at 8:30.

Was anyone working anywhere near there today? There is no elog.

If not, we will have to put a 'no janitor' sign on all of the 40m doors permanently to prevent mops misaligning our interferometer.

Attachment 1: kicked.png
  9666   Mon Feb 24 17:59:31 2014 RANAUpdateElectronicsMeasured REFL165 demod board


 Demod boards should be at 90 deg, not 82.7 or 12 or yellow or ****. We should re-inject the RF and then set the D Phase in the filter module to make the signals orthogonal. 165 is a challenging one to get right, but its worth it since the signals are close to degenerate already.

  11138   Thu Mar 12 19:54:31 2015 Q UpdateLSCHow to: PRY

Q doesn't like elogging, but he sent me this nice detailed email, so I'm copying it into the log:

I’ve locked the power recycled Y arm numerous times today, to try and find a usable AO recipe for the full locking.

Really, the “only" things that I think are different are the DC gain and pole frequency of the REFL11 CARM signal. The pole frequency can be simulated in the CM board (through the 1.4k:80 zero/pole pair), and the DC gain can be changed by changing the REFL1 gain on the CM board. 
The crossover frequency only depends on the relative gains of the digital and AO path, which is independent of these two factors, since they’re common to both. So, if we scale the common part appropriately, the same AO crossover procedure should work. I think.
So, concretely, I set up the gain in the CM_SLOW input filter so that 1x CM_SLOW_OUT -> CARM in the input matrix matched the ~120Hz UGF that we get with a gain 6 or 7 in the CARM FM. The REFL1 gain on the CM board was 0dB. 
I then normalized the signal by 1/Trmax. (i.e. I had TRY of ~3.3, so I put 0.30 in the normalization matrix), so that at full resonance, the slope should bee the same as with no normalizing. 
Then, with the Yarm locked on ALS through 1xCARM_A, PRY locked on REFL165, and at zero arm offset (TRY~3.3), I did the following
  • Transition the digital loop from 1xCARM_A (ALS) to 1xCARM_B (1xCM_SLOW_OUT)
  • Turn on CM_SLOW FM1 (whitening)
  • With CM board gains: 0db REFL1, 0dB AO, negative polarity, MC In2 gain=-32dB, turn on In2 on MC servo
  • Slowly ramp up MC In2 gain to -10dB (this starts pulling up the phase bubble of the loop)
  • Turn on the 300:80 filter in the CM_SLOW input filter (this provides a f^-2 slope around the crossover region)
  • Go from [AO,REFL1]=[-10,0] to [-4,+6] by stepping them together. (This brings you to a UGF of a few hundred Hz with tons of phase margin)
  • At this point, up the REFL1 gain to +12 or so. Turn on the :300 FM in the CM_SLOW input filter (This rolls off the digital part of the loop, makes the violin filters stop interfering with the shape)
  • UGF is now ~1kHz. Boosts can be turned on once the gain is ramped up high enough. 
The moral of the story is: if you set the REFL1 gain such that a +1.0 element in the input matrix gives you about the right UGF, then the above recipe should work, just with the REFL1 gains offset by your starting gain. (I suppose if you need a minus sign in the input matrix, that just means that the AO polarity needs to change too)
Every time the REFL1 gain is changed, the electronic offset changes, so I had to keep an eye on POY as a DC out-of-loop sensor and adjust the CM board voltage offset. For the full IFO, I think REFL55 would work for this. However, I hope that, since less REFL1 gain will be needed for the PRFPMI, the changes will be smaller….
Lastly, I think it’s good to keep the digital UGF at around 120, because the crossover steals some gain below the UGF, and you want to have some gain margin there. Turning off boosts may help with this too; I did all of this with all the normal CARM boosts on. 
Hope this made some sense!
  12220   Tue Jun 28 16:09:41 2016 PrafulUpdateGeneral40m Summary Pages

Set up gwsumm on optimus and generated summary pages from both L1 and C1 data. Still a few manual steps need to be taken during generation, not fully automated due to some network/username issues. nds2 now working from optimus after restarting nds2 server.

  12221   Tue Jun 28 16:10:49 2016 PrafulUpdateGeneralBluebird Microphones

Found 1 out of 2 bluebird microphones in the 40m.

  12222   Tue Jun 28 17:11:27 2016 PrafulUpdateGeneralEM172 Microphones

Found 60 EM172 microphones. Previous elog with details: 7777.

  12239   Fri Jul 1 17:51:28 2016 PrafulSummaryElectronicsReplacing DIMM on Optimus

There has been an ongoing memory error in optimus with the following messages:

controls@optimus|~ >
Message from syslogd@optimus at Jun 30 14:57:48 ...
 kernel:[1292439.705127] [Hardware Error]: Corrected error, no action required.

Message from syslogd@optimus at Jun 30 14:57:48 ...
 kernel:[1292439.705174] [Hardware Error]: CPU:24 (10:4:2) MC4_STATUS[Over|CE|MiscV|-|AddrV|CECC]: 0xdc04410032080a13

Message from syslogd@optimus at Jun 30 14:57:48 ...
 kernel:[1292439.705237] [Hardware Error]: MC4_ADDR: 0x0000001ad2bd06d0

Message from syslogd@optimus at Jun 30 14:57:48 ...
 kernel:[1292439.705264] [Hardware Error]: MC4 Error (node 6): DRAM ECC error detected on the NB.

Message from syslogd@optimus at Jun 30 14:57:48 ...
 kernel:[1292439.705323] [Hardware Error]: cache level: L3/GEN, mem/io: MEM, mem-tx: RD, part-proc: RES (no timeout)

Optimus is a Sun Fire X4600 M2 Split-Plane server. Based on this message, the issue seems to be in memory controller (MC) 6, chip set row (csrow) 7, channel 0. I got this same result again after installing edac-utils and running edac-util -v, which gave me:

mc6: csrow7: mc#6csrow#7channel#0: 287 Corrected Errors 

and said that all other DIMMs were working fine with 0 errors. Each MC has 4 csrows numbered 4-7. I shut off optimus and checked inside and found that it consists of 8 CPU slots lined up horizontally, each with 4 DIMMs stacked vertically and 4 empty DIMM slots beneath. I'm thinking that each of the 8 CPU slots has its own memory controller (0-7) and that the csrow corresponds to the position in the vertical stack, with csrow 7 being the topmost DIMM in the stack. This would mean that MC 6, csrow 7 would be the 7th memory controller, topmost DIMM. The channel would then correspond to which one of the DIMMs in the pair is faulty although if the DIMM was replaced, both channels 0 and 1 would be switched out. Here are some sources that I used:




I'll find the exact part needed to replace soon.

  12244   Tue Jul 5 18:44:39 2016 PrafulUpdateComputer Scripts / ProgramsWorking 40m Summary Pages

After hardware errors prevented me from using optimus, I switched my generation of summary pages back to the clusters. A day's worth of data is still too much to process using one computer, but I have successfully made summary pages for a timescales of a couple of hours on this site: https://ldas-jobs.ligo.caltech.edu/~praful.vasireddy/


Currently, I'm working on learning the current plot-generation code so that it can eventually be modified to include an interactive component (e.g., hovering over a point on a timeseries would display the GPS time). Also, the 40m summary pages have been down for the past 3 weeks but should be up and working soon as the clusters are now alive.

  12252   Wed Jul 6 11:02:41 2016 PrafulUpdateComputer Scripts / ProgramsVMon Tab on Summary Pages

I've added a new tab for VMon under the SUS parent tab. I'm still working out the scale and units, but let me know if you think this is a useful addition. Here's a link to my summary page that has this tab: https://ldas-jobs.ligo.caltech.edu/~praful.vasireddy/1151193617-1151193917/sus/vmon/

I'll have another tab with VMon BLRMS up soon.

Also, the main summary pages should be back online soon after Max fixed a bug. I'll try to add the SUS/VMon tab to the main pages as well.

  12254   Wed Jul 6 17:17:22 2016 PrafulUpdateComputer Scripts / ProgramsNew Tabs and Working Summary Pages

The main C1 summary pages are back online now thanks to Max and Duncan, with a gap in pages from June 8th to July 4th. Also, I've added my new VMon and Sensors tabs to the SUS parent tab on the main pages. These new tabs are now up and running on the July 7th summary page.

Here's a link to the main nodus pages with the new tabs: https://nodus.ligo.caltech.edu:30889/detcharsummary/day/20160707/sus/vmon/

And another to my ldas page with the tabs implemented: https://ldas-jobs.ligo.caltech.edu/~praful.vasireddy/1150848017-1150848317/sus/vmon/

Let me know if you have any suggestions or see anything wrong with these additions, I'm still working on getting the scales to be right for all graphs.

  12275   Fri Jul 8 15:44:07 2016 PrafulUpdateElectronicsReplacing DIMM on Optimus

Optimus' memory errors are back so I found the exact DIMM model needed to replace: http://www.ebay.com/itm/Lot-of-10-Samsung-4GB-2Rx4-PC2-5300P-555-12-L0-M393T5160QZA-CE6-ECC-Memory-/201604698112?hash=item2ef0939000:g:EgEAAOSwqBJXWFZh I'm not sure what website would be the best for buying new DIMMs but this is the part we need: Samsung 4GB 2Rx4 PC2-5300P-555-12-L0 M393T5160QZA-CE6.

  12277   Fri Jul 8 19:33:16 2016 PrafulUpdateComputer Scripts / ProgramsMEDM Tab on Summary Pages

A new MEDM tab has been added to the summary pages (https://nodus.ligo.caltech.edu:30889/detcharsummary/day/20160708/medm/), although some of the screens are not updated when /cvs/cds/projects/statScreen/cronjob.sh is run. In /cvs/cds/projects/statScreen/log.txt, the following error is given for those files: import: unable to read X window image `0x20011f': Resource temporarily unavailable @ error/xwindow.c/XImportImage/5027. If anyone has seen this error before or knows how to fix it, please let me know.

In the meantime, I'll be working on creating an archive of MEDM screens for every hour to be displayed on the summary pages.

  12280   Fri Jul 8 21:15:03 2016 PrafulUpdateComputer Scripts / ProgramsMEDM Tab on Summary Pages

Thanks! Yes, only the screens that are not updated when the script is executed show this error. I'll try to keep debugging over the weekend.


Very nice!

Some of the screens are up-to-date, and some are not. Are the errors associated with the screens that failed to get updated?


  12329   Mon Jul 25 10:54:55 2016 PrafulUpdateComputer Scripts / ProgramsFinished MEDM Tab on Summary Pages

The MEDM screen capture tab is now working and up on the summary pages: https://nodus.ligo.caltech.edu:30889/detcharsummary/day/20160725/medm/

Please let me know if you have any suggestions or notice any issues.

  12344   Wed Jul 27 22:42:00 2016 PrafulUpdateElectronicsEM172 Amplifier

I recreated Den's microphone amplifier circuit on a solderless breadboard to test it and make sure it does what it's supposed to. So far it seems like everything is working- I'll do some testing tomorrow to see what the amplified output is like for some test noises. Here's the circuit diagram that Den made (his elog as well https://nodus.ligo.caltech.edu:8081/40m/6651):

I'm not sure why he set up the circuit the way he did- he has pin 7 grounded and pin 4 going to +12V while in the datasheet for the opamp (http://cds.linear.com/docs/en/datasheet/1677fa.pdf), pin 7 goes to positive voltage and pin 4 goes to negative voltage. There's some other strange things about the circuit that I don't really understand, such as the motivation for using no negative voltage source, but for now I'm going to stick with Den's design and then make some modifications after I have things working and a better understanding of the problem.

Here's my current plan:

-Make sure Den's amplifier works, test it out and make changes if necessary

-Make multiple amplifier circuits on soldering breadboard

-Either make a new amplifier box or reuse Den's old box depending on how many changes I make to the original circuit

-Solder EM172s to BNC connectors, set them up around the floor suspended

-Get the amplifier box hooked up, set up some data channels for the acoustic noise

-Add new acoustic noise tab to the summary pages


Den also mentioned that he wanted me to measure the coupling of acoustic noise to DARM.

  12356   Fri Jul 29 19:37:43 2016 PrafulUpdateElectronicsMic Amplifier

I set up a test inverting amplifier circuit using the LT1677 opamp:

The input signal was a sine wave from the function generator with peak to peak amplitude of 20 mV and a frequency of 500 Hz and I received an output with an amplitude of about 670 mV and the same 500 Hz frequency, agreeing with the expected gain of -332k/10k = -33.2:

So now I know that the LT1677 works as expected with a negative supply voltage. My issue with Den's original circuit is that I was getting some clipping on the input to pin 2, which didn't seem to be due to any of the capacitors- I switched them all out. I set up a modified version of Den's circuit using a negative voltage input to see if I could fix this clipping issue:

I might reduce the input voltages to +5V and -5V- I couldn't get my inverting amp circuit to work with +12V and -12V. I'll start testing this new circuit next week and start setting up some amplifier boxes.

Attachment 1: inverting_amp.pdf
Attachment 4: inverting_amp.png
Attachment 6: new_amp_scheme.png
  12369   Wed Aug 3 18:53:46 2016 PrafulUpdateElectronicsMic Amplifier

I could not get Den's circuit to work for some reason with microphone input, so I decided to try to use another circuit I found online. I made some modifications to this circuit and made a schematic:

Using this circuit, I have been able to amplify microphone input and adjust my passband. Currently, this circuit has a high-pass at about 7 Hz and a low-pass at about 23 kHz. I tested the microphone using Audacity, an audio testing program. I produced various sine waves at different frequencies using this program and confirmed that my passband was working as intended. I also used a function generator to ensure that the gain fell off at the cutoff frequencies. Finally, I measured the frequency response of my amplifier circuit:


A text file with the parameters of my frequency response and the raw data is attached as well.

These results are encouraging but I wanted to get some feedback on this new circuit before continuing. This circuit seems to do everything that Den's circuit did but in this case I have a better understanding of the functions of the circuit elements and it is slightly simpler.

Attachment 2: ampTest_03-08-2016_180448.pdf
Attachment 3: ampTest_03-08-2016_180448.txt
# SR785 Measurement - Timestamp: Aug 03 2016 - 18:04:48
#---------- Measurement Setup ------------
# Start frequency (Hz) = 1.000000
# Stop frequency (Hz) = 102400.000000
# Number of frequency points = 800
# Excitation amplitude (mV) = 50.000000
# Settling cycles = 1
# Integration cycles = 5
#---------- Measurement Parameters ----------
# Measurement Group:  "Swept Sine" "Swept Sine"
... 820 more lines ...
Attachment 4: simple_amp.png
  12374   Thu Aug 4 17:29:17 2016 PrafulUpdateGeneralGuralp Cable

The Guralp cable has been pulled and put in the corner to the left of the water cooler:


Ben came by today before the cable had been pulled but he said he'll be back tomorrow.

  12380   Fri Aug 5 16:25:08 2016 PrafulUpdateElectronicsMic Amplifier

I took the spectrum of an EM172 connected to my amplifier inside and outside a large box filled with foam layers:

I also made a diagram with my plan for the microphone amplifier boxes. This is a bottom view:

The dimensions I got from this box: http://www.digikey.com/product-detail/en/bud-industries/CU-4472/377-1476-ND/696705

This seemed like the size I was looking for and it has a mounting flange that could make suspending it easier. Let me know if you have any suggestions.

I'll be doing a Huddle test next week to get a better idea of the noise floor and well as starting construction of the circuits to go inside the boxes and the boxes themselves.

  12387   Tue Aug 9 15:50:30 2016 PrafulUpdateGeneralGuralp Cable

The Guralp cable has been reconnected and powered after having the connector changed out.

  12395   Wed Aug 10 18:10:26 2016 PrafulUpdateElectronicsMic Amplifier

I set up 3 of my circuits in the interferometer near MC2 to do a huddle test. I have the signals from my microphones going into C1:PEM-MIC_1_IN1, C1:PEM-MIC_2_IN1, and C1:PEM-MIC_3_IN1. These are channels C17-C19. Here are some pictures of my setup:

I'll likely be collecting data from this for a couple of hours. Please don't touch it for now- it should be gone soon. There are some wires running along the floor near MC2 as well.

  12400   Thu Aug 11 11:51:38 2016 PrafulUpdateComputer Scripts / ProgramsSummary Pages

The summary pages have been updated with the new naming seismometer channel naming conventions. Here's a link to them working on my own page: https://ldas-jobs.ligo.caltech.edu/~praful.vasireddy/1154908817-1154909717/pem/seismic/

Let me know if the actual pages aren't working when they come back online or if there's something that needs to be changed.

  12402   Thu Aug 11 17:30:05 2016 PrafulUpdateElectronicsMic Amplifier

The results of my first huddle test were not so good- one of the signals did not match the other two very well- so I changed the setup so that the mics would be better oriented to receive the same signal. Pictures of the new setup are attached.

I also noticed some problems with one of my microphones so I soldered a new mic to bnc and switched it out. Just judging from Dataviewer, the signals seem to be more similar now. I'll be taking data for another few hours to confirm.

  12405   Fri Aug 12 19:13:25 2016 PrafulUpdateElectronicsMic Self Noise

I used the Wiener filtering method described by Ignacio and Jessica (https://dcc.ligo.org/DocDB/0119/T1500195/002/SURF_Final.pdf and https://dcc.ligo.org/public/0119/T1500194/001/Final_Report.pdf) and got the following results:




The channel readout has a gain of 0.0005 and the ADC is 16-bit and operates are 20V. The channel also reads the data out in Pa. I therefore had to multiply the timeseries by 1/0.0005=2000 to get it in units of counts and then by (20 Volts)/(2^16 counts) to get back to the original signal in volts. The PSDs were generated after doing this calibration. I also squared, integrated, and square rooted the PSDs to get an RMS voltage for each microphone as a sanity check:

Mic 1: 0.00036 V

Mic 2: 0.00023 V

Mic 3: 0.00028 V

These values seem reasonable given that the timeseries look like this:




Attachment 4: mic1_wiener.pdf
Attachment 5: mic2_wiener.pdf
Attachment 6: mic3_wiener.pdf
Attachment 7: timeseries_elog.pdf
  12408   Mon Aug 15 12:23:56 2016 PrafulUpdatePEMMic Self Noise

I didn't have a separate training set and data set, so I think that's why the graphs came out looking too good. The units on the graphs are also incorrect, I was interpreting PSD as ASD. I haven't been able to get my Wiener filtering code working well- I get unreasonable subtractions like the noise being larger than the unfiltered signal, so Eric showed me this frequency-dependent calculation described here: https://dcc.ligo.org/LIGO-P990002

This seems to be working well so far:




Here's all the plots on one figure:


Let me know if this looks believable.


Seems to good to be true. Maybe you're over fitting? Please put all the traces on one plot and let us know how you do the parameter setting. You should use half the data for training the filter and the second half for doing the subtraction.


Attachment 1: freq1.png
Attachment 2: freq1.pdf
Attachment 4: freq2.pdf
Attachment 6: freq3.pdf
Attachment 8: frequency_dependent.pdf
  12427   Sun Aug 21 17:21:22 2016 PrafulUpdateElectronicsProblems with PCB Circuit

For the past week, I've been trying to make a soldered amplifier circuit to use in a prototype box, However, I've been running into this same issue. The circuit, pictured below, works fine on a solderless breadboard.


When I amplify a sine wave, I get a clean looking result at the output on the solderless breadboard:

However, on my soldered circuit, if I turn up the negative voltage supply from the power supply past about -12.5V (the target is -15V), I get a strange signal that Gautam suggested looks like some kind of discharging.

At -12.3 V (soldered breadboard):

At -15.0 V (soldered breadboard):

The signal is much noisier. Zooming in on this second signal, this pattern appears:

This pattern is also showing up even when there is no input from the function generator and the circuit is just given a voltage supply of +/- 15V:

I have tried switching out both the positive and negative voltage regulators, the opamp, and remaking and resoldering the entire circuit but I'm still getting the same signal, which is absent from the solderless circuit. This output was produced with a function generator, so I have also ruled out the microphone as a source of this extra noise. The voltage dependence of this problem made me think it was the voltage regulator, but I've switched out the voltage regulator multiple times and it's still showing up. I'm not sure why this signal appears only as the negative voltage supply is increased- there is no problem with increasing the positive input voltage. Please let me know if you have any ideas as to what component or issue could be causing this.

Attachment 2: simple_amp.png
Attachment 4: clean.jpg
Attachment 5: -12.jpg
Attachment 6: -15.jpg
Attachment 7: pat1.jpg
Attachment 8: pat2.jpg
Attachment 10: bad.jpg
Attachment 11: pattern.jpg
Attachment 12: pattern2.jpg
Attachment 13: pat2.jpg
Attachment 16: patternzoomed.jpg
  12431   Mon Aug 22 18:35:16 2016 PrafulUpdatePEMthe lab temp is up

The temperature is decreasing slowly but is still above 24 C.



The IFO room temp is up a bit and it is coming down. The out side temp is not really high.


Attachment 1: temp_plot.png
Attachment 3: temp_plot.png
  12433   Tue Aug 23 17:05:20 2016 PrafulUpdateElectronicsSoldered Circuit Working

I remade another soldered circuit, adding extra 100uF electrolytic bypass capacitors at the input and output of the voltage regulator and ensuring that every grounded component now has its own path to ground rather than going through other elements. This circuit now seems to be working just like the solderless circuit. Attached is the transfer function of the soldered circuit, which matches with the result from the solderless circuit.




Here are both on the same figure- they are about overlapping but are slightly different if you zoom in enough.


I have also attached a new version of the circuit schematic to reflect the changes and to make the physical layout more clear.


My next step for these last few days this summer will be designing a PCB using Altium. I've emailed Varun about how to use Altium on the iMac but he hasn't responded. If anyone else knows how to use the software, please let me know.

Attachment 2: soldered_transfer_function.png
Attachment 3: soldered_transfer_function.png
Attachment 5: solderless_transfer_function.png
Attachment 6: both_transfer.png
Attachment 8: both_transfer.png
Attachment 10: simple_ampv2.pdf
  12436   Wed Aug 24 14:11:09 2016 PrafulUpdateElectronicsMicrophone Testing

I added an EM172 to my soldered circuit and it seems to be working so far. I have taken a spectra using the EM172 in ambient noise in the control room as well as in white noise from Audacity. My computer's speakers are not very good so the white noise results aren't great but this was mainly to confirm that the microphone is actually working.


Attachment 1: white_v_ambient.png
Attachment 2: white_v_ambient.pdf
Attachment 3: white_v_ambient.pdf
ELOG V3.1.3-