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ID Date Author Type Category Subject
2363   Tue Dec 8 03:53:49 2009 kiwamuUpdateSUSFree swinging spectra of ETMX

In this night, I checked the free swinging spectra of ETMX to make sure nothing wrong with ETMX by the wiping.

Compared with the past (Aug.6 2008), the spectra of ETMX doesn't show significant change.

Successfully the wiping activity didn't change its configuration so much and didn't bring bad situations.

(bad situation means for example, the suspended components hit some others).

The spectra of ETMX by DTT are attached. Also you can see the past spectra in Yoichi's entry.

Yoichi's data was taken during the air-pressure condition, so it's good for comparing.

Actually I compared those data by my eyes, because I could not get the past raw data somehow.

The resonant frequencies and their typical height changed a little bit, but I think those are not significant.

NOTE: In the figure, pitch and yaw modes (~0.57Hz and ~0.58Hz) look like having a smaller Q-factor than the past.

Attachment 1: ETMX_air.png
807   Thu Aug 7 10:07:13 2008 YoichiUpdateSUSFree swinging OSEM spectra
Looks like there are more extra peaks in the SRM than other optics.
Maybe because it is closer to the door ?
Attachment 1: FreeSwingSpectra.pdf
808   Thu Aug 7 10:27:59 2008 ranaUpdateSUSFree swinging OSEM spectra
Sometimes we see extra peaks in the OSEM spectra coming from a beat between the regular eigenmodes.
This probably comes from the OSEM shadow sensor not being entirely linear - the nonlinearity is
greatly increased if the magnet is not perfectly centered in the LED beam. So the beats are
probably there at some level in all of them; usually below the noise.
9113   Thu Sep 5 15:18:41 2013 JenneUpdateLSCFree swinging DRMI power buildups

I have the DRMI free swinging right now, since it's not really locking.  Looking at these time series in the attached pdf, particularly around time=1.15, it would be super handy to trigger the SRCL degree of freedom on AS110 after the PRMI is triggered on POP22.

Attachment 1: DRMI_free_swing_power_buildups.pdf
836   Thu Aug 14 19:08:14 2008 YoichiConfigurationSUSFree swing measurement going on
I started free swinging spectra measurement of all the suspensions now Aug 14 19:05 (PDT).
The watch dogs are all shutdown. Please do not turn them back on until tomorrow morning.
12523   Thu Sep 29 16:19:29 2016 LydiaUpdateSUSFree swing eigenmodes

[Lydia, Teng]

Motivated by the strange pitch/yaw coupling behavior we ran into while doing diagonalization, we looked at the oplev pitch and yaw free swing spectra for all 4 test masses (see attachment 1). We saw the same behavior there: At the peak frequencies for the angular degress of freedom, the oplevs saw significant contributions from both pitch and yaw. We also examined the phase between pitch and yaw at these peaks and found that consistently, pitch and yaw were in phase at one of the resonance frequencies and out of phase at the other (ignoring the pos and side peaks).

This corresponds physically to angular motion about some axis that is diagonal, ie not perfectly vertical or horizontal. If we trust the oplev calibration, and Eric says that we do, then the angle of this axis of rotation with the horizontal (pitch axis) is

$\theta = \arctan \frac{Y\left ( f_{peak} \right )}{P\left ( f_{peak} \right )}$

Where Y and P are yaw and pitch ASD values. This will always give an angle between 0 and 90 degrees; which quadrant the axis of rotation occupies can be dermined by looking at the phase between pitch and yaw at the same frequencies. 0 phase means that the axis of rotation lies somewhere less than 90 degrees counterclockwise from the horizontal as viewed from the AR face of the optic, and a phase of 180 degrees means the axis is clockwise from horizontal (see attachment 2). Qualitatively, these features show up the same way for segments of data taken at different times. In order to get some quantitative sense of the error in these angles, we found them using spectrogram values with a bandwidth of 0.02 Hz averaged over 4000 seconds.

Results (all numbers in degrees unless otherwise specified):

ITMY
peak 1 ( 0.692  Hz):
mean: 24.991
std: 1.23576
ptich/yaw phase: -179.181
peak 2 ( 0.736  Hz):
mean: 21.7593
std: 0.575193
pitch/yaw phase: 0.0123677

ITMX
peak 1 ( 0.502  Hz):
mean: 17.4542
std: 0.745867
ptich/yaw phase: -179.471
peak 2 ( 0.688  Hz):
mean: 74.822
std: 0.455678
pitch/yaw phase: -0.43991

ETMX
peak 1 ( 0.73  Hz):
mean: 43.1952
std: 1.54336
ptich/yaw phase: -0.227034
peak 2 ( 0.85  Hz):
mean: 60.7117
std: 0.29474
pitch/yaw phase: -179.856

ETMY
peak 1 ( 0.724  Hz):
mean: 78.2868
std: 2.18966
ptich/yaw phase: 6.03312
peak 2 ( 0.844  Hz):
mean: 26.0415
std: 2.10249
pitch/yaw phase: -176.838

ETMY and ITMX both show a more significant (~4x) contribution from pitch on one peak, and from yaw on the other. This is reflected in the fact that they each have one angle somewhat close to 0 (below 30 degrees) and one close to 90 (above 60 degrees). The other two test masses don't follow this rule, meaning that the 2 angular frequency peaks do not correspond to pitch and yaw straightforwardly.

Also, besides ITMX, the axes of rotation are at least several degrees away from being perpendicular to each other.

Attachment 1: 05.png
Attachment 2: SUS_eigenmodes.png
2391   Thu Dec 10 17:13:36 2009 kiwamuUpdateSUSFree swiging spectra under the atmospheric pressure

The free swinging spectra of ITMs, ETMs, BS, PRM and SRM were measured last night in order to make sure that nothing wrong have happened by the wiping.

I think there are nothing wrong with ITMs, ETMs, BS, PRM and SRM successfully.

For the comparison, Yoichi's figure in his elog entry of Aug.7 2008 is good, but in his figure somehow PRM spectrum doesn't look correct.

Anyway, compared with his past data, there are no significant changes in the spectra. For PRM which has no counterpart to compare with, its shape of spectra looks similar to any other spectra. So I think PRM is also OK. The measured spectra are attached below.

Indeed the current data are still showing smaller peak height for their pitch and yaw modes (roughly factor of 10 ).

Attachment 1: summary_freeswing.pdf
5344   Tue Sep 6 17:43:01 2011 SureshUpdateIOOFree Swing ITMY started

Free swing of ITMY started at

Tue Sep  6 17:41:43 PDT 2011

5347   Tue Sep 6 17:56:53 2011 JenneUpdateIOOFree Swing ITMY started

 Quote: Free swing of ITMY started at Tue Sep  6 17:41:43 PDT 2011

I think Kiwamu accidentally restarted this kick at 17:48:02 PDT.

9159   Wed Sep 25 17:07:08 2013 ranaFrogsTreasureFree Green Mango Juice in fridge

its an acquired taste, but its a must since we're sending an interferometer to India

13356   Wed Oct 4 17:18:15 2017 gautamUpdateCDSFree DAC channels in c1lsc

There are at least 5 free DAC channels (4 if you discount the one channel from these that I am hijacking) available in the 1Y2 electronics rack.

Jamie's nice wiring diagram shows the topology - the actual DAC card sits in 1Y3 inside the c1lsc expansion chassis (while the c1lsc frontend itself is in 1X4). The output of the DAC goes via SCSI to an interface box (D080303) and then to some dewhitening/AI boards (D000316). There are a total of 16 DAC channels available, out of which 8 are used for the TTs, 2 are used for the DAFI model, and one is labeleld "From c1ioo 1X2" (I don't know what this one is for). So I'm going to use some of these channels for measuring the coupling of oscillator noise and intensity noise to MICH in the DRMI lock.

The de-whitening/AI board seems to be old - it has 2x 800Hz Butterworth LPFs and no notch for the clock frequency, but maybe this doesn't matter for the tests I have in mind. The AI board available on 1X2 is more modern but routing the DAC channels from 1Y2 to it is going to be some work.

I'm going to add my testpoint to c1daf given that it seems to be the least critical model on c1lsc.

EDIT: testpoints added to c1daf don't show up in the list of available channels - there was some issue with this model while we were getting the new RTCDS going. So I'm moving my temporary testpoint to c1cal instead.

4319   Thu Feb 17 23:41:46 2011 ranaFrogsDAQFrames Directory got the wrong name: Data unreachable

DTT stopped working for recent data. An 'ls' in the frames/full/ directory reveals:

drwxr-xr-x 2 controls controls 258048 Feb  3 12:26 9807 drwxr-xr-x 2 controls controls 258048 Feb  4 16:13 9808 drwxr-xr-x 2 controls controls 262144 Feb  5 19:59 9809 drwxr-xr-x 2 controls controls 258048 Feb  6 23:46 9810 drwxr-xr-x 2 controls controls 258048 Feb  8 03:33 9811 drwxr-xr-x 2 controls controls 262144 Feb  9 07:19 9812 drwxr-xr-x 2 controls controls 253952 Feb 10 11:06 9813 drwxr-xr-x 2 controls controls 266240 Feb 11 14:53 9814 drwxr-xr-x 2 controls controls 266240 Feb 12 18:39 9815 drwxr-xr-x 2 controls controls 266240 Feb 13 22:26 9816 drwxr-xr-x 2 controls controls 262144 Feb 15 02:13 9817 drwxr-xr-x 2 controls controls 253952 Feb 16 05:59 9818 drwxr-xr-x 2 controls controls 241664 Feb 17 09:46 9819 drwxr-xr-x 2 controls controls  28672 Feb 17 12:22 9820 drwxr-xr-x 2 controls controls  32768 Feb 17 15:06 6663 drwxr-xr-x 2 controls controls  73728 Feb 17 23:39 6664 controls@fb /frames/full $date Thu Feb 17 23:39:27 PST 2011 14356 Thu Dec 13 22:56:28 2018 gautamUpdateCDSFrames [koji, gautam] We looked into the /frames situation a bit tonight. Here is a summary: 1. We have already lost some second trend data since the new FB has been running from ~August 2017. 2. The minute trend data is still safe from that period, we believe. 3. The Jetstor has ~2TB of trend data in the /frames/trend folder. • This is a combination of "second", "minute_raw" and "minute". • It is not clear to us what the distinction is between "minute_raw" and "minute", except that the latter seems to go back farther in time than the former. • Even so, the minute trend folder from October 2011 is empty - how did we manage to get the long term trend data?? From the folder volumes, it appears that the oldest available trend data is from ~July 24 2015. Plan of action: 1. The wiper script needs to be tweaked a bit to allow more storage for the minute trends (which we presumably want to keep for long term). 2. We need to clear up some space on FB1 to transfer the old trend data from Jetstor to FB1. 3. We need to revive the data backup via LDAS. Also summary pages. BTW - the last chiara (shared drive) backup was October 16 6 am. dmesg showed a bunch of errors, Koji is now running fsck in a tmux session on chiara, let's see if that repairs the errors. We missed the opportunity to swap in the 4TB backup disk, so we will do this at the next opportunity. 4109 Wed Jan 5 00:23:30 2011 ranaSummaryDAQFrameBuilder fails in a new way Since Leo was trying to demo his LIGO Data Listener code, he noticed that there was and NDS2 issue. The NDS2 guy (JZ) noticed that the FrameBuilder had an issue. We investigated. At 4PM on Dec 31, the GPS timestamp of the frame file names started to be recorded wrong. In fact, it started to give it a file name matching the correct time from 1 year in the past. So that's our version of the Y2011 bug. Here's the 'ls' of /frames/full: drwxr-xr-x 2 controls controls 252K Dec 26 03:59 9773 drwxr-xr-x 2 controls controls 260K Dec 27 07:46 9774 drwxr-xr-x 2 controls controls 256K Dec 28 11:33 9775 drwxr-xr-x 2 controls controls 252K Dec 29 15:19 9776 drwxr-xr-x 2 controls controls 244K Dec 30 19:06 9777 drwxr-xr-x 2 controls controls 188K Dec 31 16:00 9778 drwxr-xr-x 2 controls controls 148K Jan 1 08:53 9463 drwxr-xr-x 2 controls controls 260K Jan 2 12:39 9464 drwxr-xr-x 2 controls controls 252K Jan 3 16:26 9465 drwxr-xr-x 2 controls controls 248K Jan 4 20:13 9466 drwxr-xr-x 2 controls controls 36K Jan 5 00:22 9467 controls@fb /frames/full$ 

The culprit is the directory who's name starts out as 9463 whereas it should be 9779.

4112   Wed Jan 5 16:00:11 2011 rana, alexSummaryDAQFrameBuilder fails in a new way

Email from Alex:

Turned out to be the lack of current year information in the IRIG-B signal
received by the Symmetricom GPS card in the frame builder machine caused
this. I have added a constant in daqdrc to bring the seconds forward:

controls@fb /opt/rtcds/caltech/c1/target/
fb $grep symm daqdrc #set symm_gps_offset=-1; set symm_gps_offset=31536001; Hopefully we will be upgrading to the newer timing system at the 40M this year, so this will not happen again next year. Doing an 'ls -lrt' in /frames/full/ now shows that the names are correct: drwxr-xr-x 2 controls controls 249856 Dec 30 19:06 9777 drwxr-xr-x 2 controls controls 192512 Dec 31 16:00 9778 drwxr-xr-x 2 controls controls 151552 Jan 1 08:53 9463 drwxr-xr-x 2 controls controls 266240 Jan 2 12:39 9464 drwxr-xr-x 2 controls controls 258048 Jan 3 16:26 9465 drwxr-xr-x 2 controls controls 253952 Jan 4 20:13 9466 drwxr-xr-x 2 controls controls 151552 Jan 5 13:54 9467 drwxr-xr-x 2 controls controls 12288 Jan 5 15:57 9783 4115 Wed Jan 5 22:14:41 2011 ranaSummaryDAQFrameBuilder fails in a new way Just a proof that the DAQ is working - ran DTT on nodus from 3 hours ago. Attachment 1: Screen_shot_2011-01-05_at_10.13.21_PM.png 4510 Mon Apr 11 14:17:22 2011 josephb, jamieUpdateCDSFrame wiper script installed [Joe, Jamie, Alex] Fixes: I asked Alex which cron to use (dcron? frcron?). He promptly did the following: emerge dcron rc-update add dcron default Copied the wiper.pl script from LLO to /opt/rtcds/caltech/c1/target/fb/ At that point, I modified wiper.pl script to reduce to 95% instead of 99.7%. I added controls to the cron group on fb: sudo gpasswd -a controls cron I then added the wiper.pl to the crontab as the following line using crontab -e. 0 6 * * * /opt/rtcds/caltech/c1/target/fb/wiper.pl --delete &> /opt/rtcds/caltech/c1/target/fb/wiper.log Notes: Note, placing backups on the /frames raid array will break this script, because it compares the amount in the /frames/full/, /frames/trends/minutes, and /frames/trends/seconds to the total capacity. Apparently, we had backups from September 27th, 2010 and March 22nd, 2011. These would have broken the script in any case. We are currently removing these backups, as they are redundant data, and we have rsync'd backups of the frames and trends. We should now have approximately twice the lookback of full frames. 10600 Mon Oct 13 16:08:49 2014 JenneUpdateCDSFrame builder is mad I think the daqd process isn't running on the frame builder. I tried telnetting' to fb's port 8087 (telnet fb 8087) and typing "shutdown", but so far that is hanging and hasn't returned a prompt to me in the last few minutes. Also, if I do a "ps -ef | grep daqd" in another terminal, it hangs. I wasn't sure if this was an ntp problem (although that has been indicated in the past by 1 red block, not 2 red blocks and a white one), so I did "sudo /etc/init.d/ntp-client restart", but that didn't make any change. I also did an mxstream restart just in case, but that didn't help either. I can ssh to the frame builder, but I can't do another telnet (the first one is still hung). I get an error "telnet: Unable to connect to remote host: Invalid argument" Thoughts and suggestions are welcome! 10601 Mon Oct 13 16:57:26 2014 KojiUpdateCDSFrame builder is mad CPU load seems extremely high. You need to reboot it, I think controls@fb /proc 0$ cat loadavg
36.85 30.52 22.66 1/163 19295

10602   Mon Oct 13 17:09:38 2014 ericqUpdateCDSFrame builder is mad

This CPU load may have been me deleting some old frame files, to see if that would allow daqd to come back to life.

Daqd was segfaulting, and behaving in a manner similar to what is described here: (stack exchange link). However, I couldn't kill or revive daqd, so I rebooted the FB.

Things seem ok for now...

6582   Mon Apr 30 13:00:50 2012 SureshUpdateCDSFrame Builder is down

Frame builder is down.  PRM has tripped its watch dogs.  I have reset the watch dog on PRM and turned on the OPLEV. It has damped down.  Unable to check what happened since FB is not responding.

There was an minor earthquake yesterday morning which people could feel a few blocks away.  It could have caused the the PRM to unlock.

Jamie,Rolf,  is it okay or us to restart the FB?

6583   Mon Apr 30 13:58:25 2012 JamieUpdateCDSFrame Builder is down

 Quote: Frame builder is down.  PRM has tripped its watch dogs.  I have reset the watch dog on PRM and turned on the OPLEV. It has damped down.  Unable to check what happened since FB is not responding. There was an minor earthquake yesterday morning which people could feel a few blocks away.  It could have caused the the PRM to unlock. Jamie,Rolf,  is it okay or us to restart the FB?

If it's down it's alway ok to restart it.  If it doesn't respond or immediately crashes again after restart then it might require some investigation, but it should always be ok to restart it.

6584   Mon Apr 30 16:56:05 2012 SureshUpdateCDSFrame Builder is down

Quote:

 Quote: Frame builder is down.  PRM has tripped its watch dogs.  I have reset the watch dog on PRM and turned on the OPLEV. It has damped down.  Unable to check what happened since FB is not responding. There was an minor earthquake yesterday morning which people could feel a few blocks away.  It could have caused the the PRM to unlock. Jamie,Rolf,  is it okay or us to restart the FB?

If it's down it's alway ok to restart it.  If it doesn't respond or immediately crashes again after restart then it might require some investigation, but it should always be ok to restart it.

I tried restarting the fb in two different ways.  Neither of them re-established the connection to dtt or epics.

1) I restarted the fb from the control room console with the 'shutdown' command.  No change.

2) I halted the machine with 'shutdown -h now' and restarted it with the hardware reset button on its front-panel. No change.

The console connected to the fb showed that the network file systems did not load.  Could this have resulted in failure to start several services since it could not find the files which are stored on the network file system?

The fb is otherwise healthy since I am able to ssh into it and browse the directory structure.

6586   Mon Apr 30 20:43:33 2012 SureshUpdateCDSFrame Builder is down

Quote:

Quote:

 Quote: Frame builder is down.  PRM has tripped its watch dogs.  I have reset the watch dog on PRM and turned on the OPLEV. It has damped down.  Unable to check what happened since FB is not responding. There was an minor earthquake yesterday morning which people could feel a few blocks away.  It could have caused the the PRM to unlock. Jamie,Rolf,  is it okay or us to restart the FB?

If it's down it's alway ok to restart it.  If it doesn't respond or immediately crashes again after restart then it might require some investigation, but it should always be ok to restart it.

I tried restarting the fb in two different ways.  Neither of them re-established the connection to dtt or epics.

1) I restarted the fb from the control room console with the 'shutdown' command.  No change.

2) I halted the machine with 'shutdown -h now' and restarted it with the hardware reset button on its front-panel. No change.

The console connected to the fb showed that the network file systems did not load.  Could this have resulted in failure to start several services since it could not find the files which are stored on the network file system?

The fb is otherwise healthy since I am able to ssh into it and browse the directory structure.

[Mike, Rana]

The fb is okay.  Rana found that it works on Pianosa, but not on Allegra or Rossa.  It also works on Rosalba, on which Jamie recently installed Ubuntu.

The white fields on the medm  'Status' screen for fb are an unrelated problem.

6591   Tue May 1 08:18:50 2012 JamieUpdateCDSFrame Builder is down

 Quote: I tried restarting the fb in two different ways.  Neither of them re-established the connection to dtt or epics.

Please be conscious of what components are doing what.  The problem you were experiencing was not "frame builder down".  It was "dtt not able to connect to frame builder".  Those are potentially completely different things.  If the front end status screens show that the frame builder is fine, then it's probably not the frame builder.

Also "epics" has nothing whatsoever to do with any of this.  That's a completely different set of stuff, unrelated to DTT or the frame builder.

6160   Tue Jan 3 17:25:27 2012 KojiUpdatePSLFound the laser was off

I found the PSL laser has been off for four hours. Nobody seemed to know why.

I just turned it on and it is now providing about 10% lower power compared with one before the shutdown.
Let's keep the eyes on the power if it can recover as the housing gets warm.

8913   Tue Jul 23 21:32:43 2013 KojiUpdateIOOFound the cause of mysterious MC motion

Thesedays we were continuously annoyed by unELOGGED activities of the interferometer.

MC2 LOCKIN was left on and has continuously injected frequency noise and beam pointing modulation
during all of the comissioning / vent preparation.

C1:SUS-MC2_LOCKIN2_OSC_FREQ was 0.075
C1:SUS-MC2_LOCKIN2_OSC_CLKGAIN was 99

For more than a week ago we noticed that the curve of the MC WFS stripchart suddenly got THICKER.
MC WFS, arm transmission, beam pointing... everything was modulated.
It was not WFS instability, and it was not the cavity mirrors.

Today I made the investigation and finally tracked down the cause of this issue to be on MC2 suspension.
Then it was found that this LOCKIN was ON.

There is no direct record of this lockin in the frame files.
From the recorded channel "C1:IOO-WFS2-YAW_OUT16" (which is the trace on the StripTool chart on the wall)
It was turned on at July 10th, 2:00UTC (July 9th, 7PM PDT)

8917   Wed Jul 24 14:26:24 2013 ranaUpdateIOOFound the cause of mysterious MC motion

Yes, this was not ELOG'd by me, unfortunately. This was the MC tickler which I described to some people in the control room when I turned it on.

As Koji points out, with the MCL path turned off this injects frequency noise and pointing fluctuations into the MC. With the MCL path back on it would have very small effect. After the pumpdown we can turn it back on and have it disabled after lock is acquired. Unfortunately, our LOCKIN modules don't have a ramp available for the excitation and so this will produce some transients (or perhaps we can ezcastep it for now). Eventually, we will modify this CDS part so that we can ramp the sine wave.

9046   Wed Aug 21 19:26:19 2013 ranaUpdateIOOFound the cause of mysterious MC motion

 Quote: Yes, this was not ELOG'd by me, unfortunately. This was the MC tickler which I described to some people in the control room when I turned it on. As Koji points out, with the MCL path turned off this injects frequency noise and pointing fluctuations into the MC. With the MCL path back on it would have very small effect. After the pumpdown we can turn it back on and have it disabled after lock is acquired. Unfortunately, our LOCKIN modules don't have a ramp available for the excitation and so this will produce some transients (or perhaps we can ezcastep it for now). Eventually, we will modify this CDS part so that we can ramp the sine wave.

I've written a new TICKLE script using the newly found 'cavget' and 'cavput' programs. They are in the standard epics distribution as extension binaries. They allow multichannel read/write as well as ramping, delays, incremental steps, etc. http://www.aps.anl.gov/epics/tech-talk/2012/msg01465.php.

Running from the command line, they seem to work fine, but I've left it OFF for now. I'll switch it into the MC autolocker at some point soon.

3755   Thu Oct 21 18:45:50 2010 KojiUpdatePSLFound the beat at 1064nm

[Koji Suresh]

We found the beat at 1064nm. T(PSL)=26.59deg, T(X-end)=31.15deg.

The X-end laser was moved to the PSL table.

The beating setup was quickly constructed with mode matching based on beam profile measurements by the IR cards.
We used the 1GHz BW PD, Newfocus #1611-FS-AC.

As soon as we swept the Xtal temp of the X-end laser, we found the strong beating.

3756   Thu Oct 21 19:10:39 2010 AidanUpdatePSLFound the beat at 1064nm

 Quote: [Koji Suresh] We found the beat at 1064nm. T(PSL)=26.59deg, T(X-end)=31.15deg. The X-end laser was moved to the PSL table. The beating setup was quickly constructed with mode matching based on beam profile measurements by the IR cards. We used the 1GHz BW PD, Newfocus #1611-FS-AC. As soon as we swept the Xtal temp of the X-end laser, we found the strong beating.

3759   Fri Oct 22 01:23:13 2010 KojiUpdatePSLFound the beat at 1064nm

[Koji / Suresh]

We worked on the 1064 beating a bit more.

- First of all, FSS and FSS SLOW servo were disabled not to have variating Xtal temp for the PSL.

- The PSL Xtal temp (T_PSL) was scanned from 22deg-45deg while we search the Xtal temp (T_Xend) for the Xend laser to have the beat freq well low (f<30MHz).
The pumping current for each laser was I_PSL = 2.101 [A] and I_Xend = 2.000 [A]

For a certain T_PSL, we found multiple T_Xend because the freq of the laser is not a monotonic function of the Xtal temperature. (see the innolight manual).

T_Xend to give us the beating was categorized in the three sets as shown in the figure. The set on "curve2" is the steadiest one. (Use this!)
The trends were quite linear but the slope was slightly off from the unity.

- T_PSL was scanned to see the trend of the PMC output.

The PMC was sometimes locked to the mode with lower transmission (V_PMCT ~ 3.0V).
When T_PSL ~ 31deg we consistently locked the PMC at higer transmission (V_PMCT ~ 5.3V).

At the moment we decided the operating point of T_PSL = 32.25 deg, V_PMCT = 5.34, where we found the beat at T_Xend=38.28deg.

- We cleaned up the PSL table more than how it was. Returned the tools to their original places.
The X-end laser was shut down and was left on the PSL table.

NEXT:
Kiwamu can move the X-end laser to the Xend and realign it.
Then we should be able to see the green beating quite easily.

Attachment 1: 101021_beat.pdf
4980   Sun Jul 17 18:23:23 2011 JenneUpdatePSLFound the PMC unlocked

It was unlocked since ~4:30am.  No idea why.  It's relocked so I can try round N of measuring the PRC length.

Attachment 1: PMCunlocked_17July2011.png
8653   Thu May 30 01:02:41 2013 ManasaUpdateGreen LockingFound it!

X green beat note found!

Key points
1. Near-field and far-field alignment on the PSL table. The near-field alignment checked by looking at the camera and the far-field alignment checked by allowing the beams to propagate by removing the DC PD.
2. Check laser temperature and get a sense of how the offset translates to the actual laser temperature.
3. Get an idea of the expected temperature of laser using the plot in elog.

Data
PSL laser temperature = 31.45 deg C

X end laser temperature = 39.24 deg C
C1-ALS-X_SLOW_SEERVO2_OFFSET = 4810
Amplitude of beat note = -40dBm

I do not understand why
1. The amplitude of beatnote falls linearly with frequency (peak traced using 'hold' option of the spectrum analyzer).
2. I found the beat note at the RF output of the PD. Earlier, while I was trying to search for the beatnote from the RFmon output of the betabox, there was a strong peak at 29.6MHz that existed even when the green shutters were closed. It's source has to be traced.

Next
Solve beatbox puzzle and lock arm using ALS.

14500   Fri Mar 29 11:43:15 2019 JonUpdateUpgradeFound c1susaux database bug

I found the current bias output channels, C1:SUS-<OPTIC>_<DOF>BiasAdj, were all pointed at C1:SUS-<OPTIC>_ULBiasSet for every degree of freedom. This same issue appeared in all eight database files (one per optic), so it looks like a copy-and-paste error. I fixed them to all reference the correct degree of freedom.

3659   Wed Oct 6 12:00:23 2010 josephb, yuta, kiwamuUpdateCDSFound and fixed filter sampling rate problem with suspensions

While we looking using dtt and going over the basics of its operation, we discovered that the filter sample rates for the suspensions were still set to 2048 Hz, rather than 16384 Hz which is the new front end.  This caused the filters loaded into the front ends to not behave as expected.

After correcting the sample rate, the transfer functions obtained from dtt are now looking like the bode plots from foton.

We fixed the C1SUS.txt and C1MCS.txt files in the /opt/rtcds/caltech/c1/chans/ directory, by changing the SAMPLING lines to have 16384 rather than 2048.

15287   Tue Mar 31 09:39:41 2020 gautamUpdateCDSFoton for shaped noise injections

I'd like to re-measure the transfer function from driving MC2 position to the MC_L_DQ channel (for feedforward purposes). Swept sine would be one option, but I can't get the "Envelope" feature of DTT to work, the excitation amplitude isn't getting scaled as specified in the envelope, and so I'm unable to make the measurement near 1 Hz (which is where the FF is effective). I see some scattered mentions of such an issue in past elogs but no mention of a fix (I also feel like I have gotten the envelope function to work for some other loop measurement templates). So then I thought I'd try broadband noise injection, since that seems to have been the approach followed in the past. Again, the noise injection needs to be shaped around ~1 Hz to avoid knocking the IMC out of lock, but I can't get Foton to do shaped noise injections because it doesn't inherit the sample rate when launched from inside DTT/awggui - this is not a new issue, does anyone know the fix?

Note that we are using the gds2.15 install of foton, but the pre-packaged foton that comes with the SL7 installation doesn't work either.

Update:

The envelope feature for swept-sine wasn't working because i specified the frequency grid in the wrong order apparently. Eric von Reis has been notified to include a sorting algorithm in future DTT so that this can be in arbitrary order. fixing that allows me to run a swept sine with enveloped excitation amplitude and hence get the TF I want, but still no shaped noise injections via foton 😢

15288   Tue Mar 31 23:35:50 2020 ranaUpdateCDSFoton for shaped noise injections

do you really mean awggui cannot make shaped noise injections via its foton text box ? That has always worked for me in the past.

If this is broken I'm suspicious there's been some package installs to the shared dirs by someone.

15289   Tue Mar 31 23:54:57 2020 gautamUpdateCDSFoton for shaped noise injections

The problem is that foton does not inherit the model sample rate when launched from DTT/awggui. This is likely some shared/linked/dynamic library issue, the binaries we are running are precompiled presumably for some other OS. I've never gotten this to work since we changed to SL7 (but I did use it successfully in 2017 with the Ubuntu12 install).

 Quote: do you really mean awggui cannot make shaped noise injections via its foton text box ? That has always worked for me in the past. If this is broken I'm suspicious there's been some package installs to the shared dirs by someone.
6041   Tue Nov 29 18:31:40 2011 DenUpdatedigital noiseFoton error

In the previous elog we've compared Matlab and Foton SOS representations using low-order filter. Now we move on to high order filters and see that Foton is pretty bad here.

We consider Chebyshev filter of the first type with cuf off frequency 12 Hz and ripple 1 dB. In the table below we summarize the GAINS obtained by Matlab and Foton for different digital filter orders.

 Order Matlab Foton 2 5.1892960e-06 5.1892960e-06 4 6.8709377e-12 6.8709378e-12 6 5.4523201e-16 9.0950127e-18 8 5.3879305e-21 1.2038559e-23

We can see that for high orders the gains are completely different (ORDER of 2!!!). Interesting that besides of very bad GAIN, SOS-MATRIX Foton calculates pretty well. I checked up to 5 digit - full coincidence. Only GAIN is very bad.

The filter considered is cheby1("LowPass",6,1,12) and is a part of the bad Cheby filter where we loose coherence and see some other strange things.

6061   Thu Dec 1 18:30:39 2011 Vladimir, DenUpdatedigital noiseFoton error

Foton Matlab Error

We investigated some more the discrepancy between Matlab and Foton numbers. The comparison of cheby1(k, 1, 2*12/16384) was done between versions implemented in Matlab, R and Octave. Filters created by R and Octave agree with Foton.

Also, we found that Matlab has gross precision errors for cutoff frequencies just smaller than used in our fitler, for example cheby1(6, 2*3/16384) fails miserably.

6062   Fri Dec 2 17:43:46 2011 ranaUpdatedigital noiseFoton error

It would be useful to see some plots so we could figure out exactly what magnitude and phase error correspond to "gross" and "miserable".

5793   Thu Nov 3 13:00:52 2011 JenneUpdatePhotosFormatting of MEDM screen names

 Quote: After lots of trial and error, and a little inspiration from Koji, I have written a new script that will run when you select "update snapshot" in the yellow ! button on any MEDM screen.  Right now, it's only live for the OAF_OVERVIEW screen.  View snapshot and view prev snapshot also work.  Next on the list is to make a script that will create the yellow buttons for each screen, so I don't have to type millions of things in by hand. The script lives in:  /cvs/cds/rtcds/caltech/c1/scripts/MEDMsnapshots, and it's called....wait for it....... "updatesnap".

Currently the update snapshot script looks at the 3 letters after "C1" to determine what folder to put the snapshots in.  (It can also handle the case when there is no C1, ex. OAF_OVERVIEW.adl still goes to the c1oaf folder).  If the 3 letters after C1 are SYS, then it puts the snapshot into /opt/rtcds/caltech/c1/medm/c1sys/snap/MEDM_SCREEN_NAME.adl

Mostly this is totally okay, but a few subsystems seem to have incongruous names.  For example, there are screens called "C1ALS...." in the c1gcv folder.  Is it okay if these snapshots go into a /c1als/snap folder, or do I need to figure out how to put them in the exact same folder they currently exist in?  Or, perhaps, why aren't they just in a c1als folder to begin with? It seems like we just weren't careful when organizing these screens.

Another problem one is the C1_FE_STATUS.adl screen.  Can I create a c1gds folder, and rename that screen to C1GDS_FE_STATUS.adl?  Objections?

7348   Thu Sep 6 10:57:27 2012 JenneUpdateGeneralForgot to turn green refl pd back on

Quote:

I couldn't understand the Y-End green setup as the PD was turned off and the sign of the servo was flipped. Once they are fixed, I could lock the cavity with the green beams.

 Quote: [EricQ, Jenne, brains of other people] Get green spots co-located with IR spots on ETMs, ITMs, check path of leakage through the arms, make sure both greens get out to PSL table

I had turned the green refl PD off on Tuesday while we were doing the IPANG alignment, since the beam was not so bright, and the LED on top of the PD was very annoyingly bright.  I forgot to turn it back on.  The sign flip on the servo, I can't explain.

15417   Fri Jun 19 14:03:50 2020 JordanUpdateVACForepump Tip Seal Replacement

Tip Seals were replaced on the forepumps for TP2 and TP3, and both are ready to be installed back onto the forelines.

TP2 Forepump Ultimate Pressure: 180 mtorr

TP3 Forepump Ultimate Pressure: 120 mtorr

15022   Wed Nov 13 19:34:45 2019 gautamUpdatePEMFollow-up on seismometer discussion

Attachment #1 shows the spectra of our three available seismometers over a period of ~10ksec.

• I don't understand why the z-axis motion reported by the T240 is ~10x lower at 10 mHz compared to the X and Y motions. Is this some electronics noise artefact?
• The difference in the low frequency (<100mHz) shapes of the T240 compared to the Guralps is presumably due to the difference in the internal preamps / readout boxes (?). I haven't checked yet.
• There is almost certainly some issue with the EX Guralp. IIRC this is the one that had cabling issues in the past, and also is the one that was being futzed around for Tctrl, but also could be that its masses need re-centering, since it is EX_X that is showing the anomalous behaviour.
• The coherence structure between the other pairs of sensors is consistent.

Attachment #2 shows the result of applying frequency domain Wiener filter subtraction to the POP QPD (target) with the vertex seismometer signals as witness channels.

• The dataset was PRMI locked with the carrier resonant, ETMs misaligned.
• The dashed lines in these plots correspond to the RMS for the solid line with the same color.
• For both PIT and YAW, I am using BS_X and BS_Y seismometer channels for the MISO filter inputs.
• In particular for PIT, I notice that I am unable to get the same level of performance as in the past, particularly around ~2-3 Hz.
• The BS seismometer health indicators don't signal any obvious problems with the seismometer itself - so something has changed w.r.t. how the ground motion propagates to the PR2/PR3? Or has the seismometer sensing truly degraded? I don't think the dataset I collected was particularly bad compared to the past, and I confirmed similar performance with a separate PRMI lock from a different time period.
Attachment 1: seisAll_20191111.pdf
Attachment 2: ffPotential.pdf
15023   Wed Nov 13 20:15:56 2019 ranaUpdatePEMFollow-up on seismometer discussion

this is due to the Equivalence Principle: local accelerations are indistinguishable from spacetime curvature. On a spherical Earth, the local gradient of the metric points in the direction towards the center of the Earth, which is colloquially known as "down".

 Quote: I don't understand why the z-axis motion reported by the T240 is ~10x lower at 10 mHz compared to the X and Y motions. Is this some electronics noise artefact?

15024   Wed Nov 13 23:40:15 2019 gautamUpdatePEMFollow-up on seismometer discussion

Here is some disturbance in the spacetime curvature, where the local gradient of the metric seems to have been modulated (in the "downward" as well as in the other two orthogonal Cartesian directions) at ~1 Hz - seems real as far as I can tell, all the suspensions were being shaken about and all the seismometers witnessed it, though the peak is pretty narrow. A broader, less prominent peak also shows up around 0.5 Hz. We couldn't identify any clear source (no LN2 fill-up / obvious CES activity). This event lasted for ~45 mins, and stopped around 2315 local time. Shortly (~5min) after the ~1 Hz peak died down, however, the 3-10 Hz BLRMS channel reports an increase by ~factor of 2.

Onto trying some locking now that the suspensions have settled down somewhat.

 Quote: this is due to the Equivalence Principle: local accelerations are indistinguishable from spacetime curvature. On a spherical Earth, the local gradient of the metric points in the direction towards the center of the Earth, which is colloquially known as "down".
Attachment 1: seisAll_20191111_1Hz.pdf
15025   Thu Nov 14 12:11:04 2019 ranaUpdatePEMFollow-up on seismometer discussion

at 1 Hz' this effect is not large so that's real translation. at lower frequencies a ground tilt couples to the horizontal sensors at first order and so the apparent signal is amplified by the double integral. drawing a free body diagram u can c that

x_apparent = (g / s^2) * theta

but for vortical this not tru because it already measures the full free fall and the tilt only shows up at 2nd order

15027   Fri Nov 15 00:18:41 2019 ranaUpdatePEMFollow-up on seismometer discussion

The large ground motion at 1 Hz started up again tonight at around 23:30. I walked around the lab and nearby buildings with a flashlight and couldn't find anything whumping. The noise is very sinusoidal and seems like it must be a 1 Hz motor rather than any natural disturbance or traffic, etc. Suspect that it is a pump in the nearby CES building which is waking up and running to fill up some liquid level. Will check out in the morning.

Estimate of displacement noise based on the observed MC_F channel showing a 25 MHz peak-peak excursion for the laser:

dL = 25e6 * (13 m / (c / lambda)

= 1 micron

So this is a lot. Probably our pendulum is amplifying the ground motion by 10x, so I suspect a ground noise of ~0.1 micron peak-peak.

(this is a native PDF export using qtgrace rather than XMgrace. uninstall xmgrace and symlink to qtgrace.)

Attachment 1: MCshake.pdf
ELOG V3.1.3-