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ID Date Author Type Category Subject
2612   Thu Feb 18 10:10:43 2010 steveConfigurationGeneral480 V AC power turned off

Only the 40m cranes are running on 480VAC The electricians are rewiring this transformer on the mezzanine so it was shut down.

I tested all three cranes before the 480V power was turned off. The last thing to do with the cranes to wipe them down before use.

It will happen on next Tuesday morning.

2966   Fri May 21 11:56:34 2010 AlbertoUpdate40m Upgrading40mUpgrade Field Power and RF Power Spectrum at the ports. 38m/38.55m arm length issue.

I update my old 40mUpgrade Optickle model, by adding the latest updates in the optical layout (mirror distances, main optics transmissivities, folding mirror transmissivities, etc). I also cleaned it from a lot of useless, Advanced LIGO features.

I calculated the expected power in the fields present at the main ports of the interferometer.

I repeated the calculations for both the arms-locked/arms-unlocked configurations. I used a new set of functions that I wrote which let me evaluate the field power and RF power anywhere in the IFO. (all in my SVN directory)

As in Koji's optical layout, I set the arm length to 38m and I found that at the SP port there was much more power that I woud expect at 44Mhz and 110 MHz.

It's not straightforward to identify unequivocally what is causing it (I have about 100 frequencies going around in the IFO), but presumably the measured power at 44MHz was from the beat between f1 an f2 (55-11=44MHz), and that at 110MHz was from the f2 first sidebands.

Here's what i found:

I found that When I set the arm length to 38.55m (the old 40m average arm length), the power at 44 and 110 MHz went significantly down. See here:

I checked the distances between all the frequencies circulating in the IFO from the closest arm resonance to them.

I found that the f2 and 2*f2 are two of the closest frequencies to the arm resonance (~80KHz). With a arm cavity finesse of 450, that shouldn't be a problem, though.

I'll keep using the numbers I got to nail down the culprit.

Anyways, now the question is: what is the design length of the arms? Because if it is really 38m rather than 38.55m, then maybe we should change it back to the old values.

2968   Fri May 21 16:24:11 2010 KojiUpdateLSC40mUpgrade Field Power and RF Power Spectrum at the ports. 38m/38.55m arm length issue.

1. Give us the designed arm length. What is the criteria?

2. The arm lengths got shorter as the ITMs had to shift to the end. To make them longer is difficult. Try possible shorter length.

2973   Mon May 24 10:03:14 2010 ranaUpdateLSC40mUpgrade Field Power and RF Power Spectrum at the ports. 38m/38.55m arm length issue.

If you have a working 40m Optickle model, put it in a common place in the SVN, not in your own folder.

I can't figure out why changing the arm length would effect the RF sidebands levels. If you are getting RF sidebands resonating in the arms, then some parameter is not set correctly.

As the RF sideband frequency gets closer to resonating in the arm, the CARM/DARM cross-coupling to the short DOFs probably gets bigger.

2974   Mon May 24 11:32:05 2010 ranaUpdateLSC40mUpgrade Field Power and RF Power Spectrum at the ports. 38m/38.55m arm length issue.

 Quote: If you have a working 40m Optickle model, put it in a common place in the SVN, not in your own folder. I can't figure out why changing the arm length would effect the RF sidebands levels. If you are getting RF sidebands resonating in the arms, then some parameter is not set correctly. As the RF sideband frequency gets closer to resonating in the arm, the CARM/DARM cross-coupling to the short DOFs probably gets bigger.

I don't know the causes of this supposed resonances yet. I'm working  to try to understand that. It would be interesting also to evaluate the results of absolute length measurements.

Here is what I also found:

It seems that 44, 66 and 110 are resonating.

If that is real, than 37.5m could be a better place. Although I don't have a definition of "better" yet.  All I can say is these resonances are smaller there.

15879   Mon Mar 8 12:54:54 2021 gautamUpdateEquipment loan40m-->Cryo
1. Busby box
2. SR554 transformer preamplifier
549   Fri Jun 20 08:30:27 2008 stivUpdatePhotos40m summer line up 2008
atm1: John, Alberto, Yoichi, Koji, Masha, and Sharon

atm2: surf students Max of CIT, Sharon of MIT, Masha of Harvard, Eric of CIT not shown
Attachment 1: P1020559.png
Attachment 2: P1020560.png
6883   Wed Jun 27 15:10:34 2012 JamieUpdateComputer Scripts / Programs40m summary webpages move

I have moved the summary pages stuff that Duncan set up to a new directory that it accessible to the nodus web server and is therefore available from the outside world:

/users/public_html/40-summary

which is available at:

https://nodus.ligo.caltech.edu:30889/40m-summary/

I updated the scripts, configurations, and crontab appropriately:

/users/public_html/40m-summary/bin/c1_summary_page.sh
/users/public_html/40m-summary/share/c1_summary_page.ini

6686   Fri May 25 19:13:10 2012 Duncan MacleodSummaryComputer Scripts / Programs40m summary webpages

# 40m summary webpages

The aLIGO-style summary webpages are now running on 40m data! They are running on megatron so can be viewed from within the martian network at:

http://192.168.113.209/~controls/summary

At the moment I have configured the 5 seismic BLRMS bands, and a random set of PSL channels taken from a strip tool.

## Technical notes

• The code is in python depending heavily on the LSCSoft PyLAL and GLUE modules.
• /home/controls/public_html/summary/bin/summary_page.py
• The HTML is supported by a CSS script and a JS script which are held locally in the run directory, and JQuery linked from the google repo.
• /home/controls/public_html/summary/summary_page.css
• /home/controls/public_html/summary/pylaldq.js
• The configuration is controlled via a single INI format file
• /home/controls/public_html/summary/share/c1_summary_page.ini

### Getting frames

Since there are no segments or triggers for C1, the only data sources are GWF frames. These are mounted from the framebuilder under /frames on megatron. There is a python script that takes in a pair of GPS times and a frame type that will locate the frames for you. This is how you use it to find T type frames (second trends) for May 25 2012:

python /home/controls/public_html/summary/bin/framecache.py --ifo C1 --gps-start-time 1021939215 --gps-end-time 1022025615 --type T -o framecache.lcf

If you don't have GPS times, you can use the tconvert tool to generate them

$tconvert May 25 1021939215 The available frame types, as far as I'm aware are R (raw), T (seconds trends), and M (minute trends). ## Running the code The code is designed to be fairly easy to use, with most of the options set in the ini file. The code has three modes - day, month, or GPS start-stop pair. The month mode is a little sketchy so don't expect too much from it. To run in day mode: python /home/controls/public_html/summary/bin/summary_page.py --ifo C1 --config-file /home/controls/public_html/summary/share/c1_summary_page.ini --output-dir . --verbose --data-cache framecache.lcf -SRQDUTAZBVCXH --day 20120525 Please forgive the large apparently arbitrary collection of letters, since the 40m doesn't use segments or triggers, these options disable processing of these elements, and there are quite a few of them. They correspond to --skip-something options in long form. To see all the options, run python /home/controls/public_html/summary/bin/summary_page.py --help There is also a convenient shell script that will run over today's data in day mode, doing everything for you. This will run framecache.py to find the frames, then run summary_page.py to generate the results in the correct output directory. To use this, run bash /home/controls/public_html/summary/bin/c1_summary_page.sh ## Configuration Different data tabs are disabled via command link --skip-this-tab style options, but the content of tabs is controlled via the ini file. I'll try to give an overview of how to use these. The only configuration required for the Seismic BLRMS 0.1-0.3 Hz tab is the following section: [data-Seismic 0.1-0.3 Hz] channels = C1:PEM-RMS_STS1X_0p1_0p3,C1:PEM-RMS_STS1Y_0p1_0p3,C1:PEM-RMS_STS1Z_0p1_0p3 labels = STS1X,STS1Y,STS1Z frame-type = R plot-dataplot1 = plot-dataplot3 = amplitude-log = True amplitude-lim = 1,500 amplitude-label = BLRMS motion ($\mu$m/s) The entries can be explained as follows: 1. '[data-Seismic 0.1-0.3 Hz] - This is the section heading. The 'data-' mark identifies this as data, and is a relic of how the code is written, the 'Seismic 0.1-0.3 Hz' part is the name of the tab to be displayed in the output. 2. 'channels = ...' - This is a comma-separated list of channels as they are named in the frames. These must be exact so the code knows how to find them. 3. 'labels = STS1X,STS1Y,STS1Z' - This is a comma-separated list of labels mapping channel names to something more readable for the plots, this is optional. 4. 'frame-type = R' - This tells the code what frame type the channels are, so it can determine from which frames to read them, this is not optional, I think. 5. 'plot-dataplotX' - This tells the code I want to run dataplotX for this tab. Each 'dataplot' is defined in it's own section, and if none of these options are given, the code tries to use all of them. In this configuration 'plot-dataplot1' tells the code I want to display the time-series of data for this tab. 6. 'amplitude-XXX = YYY' - This gives the plotter specific information about this tab that overrides the defaults defined in the dataplotX section. The options in this example tell the plotter that when plotting amplitude on any plot, that axis should be log-scale, with a limit of 1-500 and with a specific label. The possible plotting configurations for this style of option are: 'lim', 'log', 'label', I think. Other compatible options not used in this example are: • scale = X,Y,Z - a comma-separated list of scale factors to apply to the data. This can either be a single entry for all channels, or one per channel, nothing in between. • offset = X,Y,Z - another comma-separate list of DC offsets to apply to the data (before scaling, by default). DAQ noise may mean a channel that should read zero during quick times is offset by some fixed amount, so you can correct that here. Again either one for all channels, or one per channel. • transform = lambda x: f(x) - a python format lambda function. This is basically any mathematical function that can be applied to each data sample. By default the code constructs the function 'lambda d: scale * (d-offset)', i.e. it calibrates the data by removing the offset an applying the scale. • band = fmin, fmax - a low,high pair of frequencies within which to bandpass the data. Sketchy at best... • ripple_db = X - the ripple in the stopband of the bandpass filter • width = X - the width in the passband of the bandpass filter • rms_average = X - number of seconds in a single RMS average (combine with band to make BLRMS) • spectrum-segment-length = X - the length of FFT to use when calculating the spectrum, as a number of samples • spectrum-overlap = X - the overlap (samples) between neighbouring FFTs when calculating the spectrum • spectrum-time-step = X - the length (seconds) of a single median-mean average for the spectrogram At the moment a package version issue means the spectrogram doesn't work, but the spectrum should. At the time of writing, to use the spectrum simple add 'plot-dataplot2'. You can view the configuration file within the webpage via the 'About' link off any page. Please e-mail any suggestions/complaints/praise to duncan.macleod@ligo.org. 6687 Fri May 25 20:45:25 2012 Duncan MacleodSummaryComputer Scripts / Programs40m summary webpages There is now a job in the crontab that will run the shell wrapper every hour, so the pages _should_ take care of themselves. If you make adjustments to the configuration file they will get picked up on the hour, or you can just run the script by hand at any time. $ crontab -l # m h  dom mon dow   command 0 */1 * * * bash /home/controls/public_html/summary/bin/c1_summary_page.sh > /dev/null 2>&1

5254   Wed Aug 17 12:14:27 2011 Josh SmithOmnistructureComputer Scripts / Programs40m summary page plans

Josh Smith, Fabian Magana-Sandoval, Jackie Lee (Fullerton)

Thanks to Jamie and Jenne for the tour and the input on the pages.

We had a look at the GEO summary pages and thought about how best to make a 40m summary page that would eventually become and aligo summary page. Here's a rough plan:

- First we'll check that we can access the 40m NDS2 server to get data from the 40m lab in Fullerton.

- We'll make a first draft of a 40m summary page in python, using pynds, and base the layout on the current geo summary pages.

- When this takes shape we'll iterate with Jamie, Jenne, Rana to get more ideas for measurements, layout.

Other suggestions: Jenne is working on an automated noisebudget and suggests having a placeholder for it on the page. We can also incorporate some of the features of Aidan's 40m overview medm screen that's in progress, possibly with different plots corresponding to different parts of the drawing, etc. Jenne also will email us the link of once per hour medm screenshots.

2115   Mon Oct 19 11:00:52 2009 steveHowToSAFETY40m safety training

Kiwamu, Alex and Zach are practicing mandatory IR-safety scan at the 40m-PSL

40m specific safety indoctrination were completed.

Attachment 1: safety_10_2009.JPG
15303   Tue Apr 14 23:50:06 2020 KojiUpdateGeneral40m power glitch recovery

[Koji / Gautam (Remote)]

Lab status

• Gray Panel: The lab AC was off. Turned on all three (N/S, CTRL RM, E/W)
• The control room AC was running.

Work stations

• Control Room: All the control machines were running. We knew that nodus/chiara/fb were running
• 1X6/7:
• JETSTOR was making beeping sound. “Power #1 failed””power #2 failed”
• Optimus & megatron were off -> turned on -> up and running now
• 1X1/2:
• Power cycled the netgear at the top of the IOO rack (maybe not necessary)
• Turned on c1ioo -> up and running now
• 1X4/5: Rebooted c1sus / c1lsc -> up and running now
• 1X9: Rebooted c1iscex -> up and running now
• 1Y4: Rebooted c1iscex -> up and running now

Vacuum status

• Looked like everything was running as if it did not see the power glitch
• TP1 normal: Set speed 33.6k rpm / Actual speed 33.6k rpm
• TP2 normal: 66k rpm / PTP2 16.0 mtorr
• TP3 normal: 31k rpm / PTP3 45.4mtorr
• P1 LOW / P2 1.7mtorr / CC2 1.1e-6 / P3 7.6e-2 / P4 LO
• Annuli: 2.7~3torr
• CC1 9.6e-6 / SUPER BEE 0.9mtorr

C1VAC recovery

• c1vac was alive, but was isolated from the martian network
• Checked the network I/F status with /sbin/ifconfig -a
• eth1 had the vac subnet IP (192.168.114.9)
• Ran sudo /sbin/ifdown eth0 then  sudo /sbin/ifup eth0
• The I/F eth0 started running and c1vac became visible from martian
• Later checked the vacuum screen: The pressure values and valve statuses looked normal.
The interlock state was “running”. The system state was “unrecognized”.

End RTS recovery

• The end slow machines (auxex and auxey) were already running
• Restarting end RT models:
• c1iscey -> rtcds start --all
• c1iscex -> rtcds start --all
• Confirmed that the models can dump the SUSs

Vertex RTS recovery

• We wanted to use the reboot script. (/opt/rtcds/caltech/c1/scripts/cds/rebootC1LSC.sh)
• c1susaux​​
• To be safe, we wanted to bring c1susaux first.
• c1susaux does not make the network I/Fs up automatically upon reboot.
-> Connect an LCD display / keyboard / mouse to c1susaux
-> Ran sudo /sbin/ifup eth0 and sudo /sbin/ifup eth1
• Now c1susaux is visible from martian.
sudo systemctl start modbusIOC.service
-> c1susaux epics is up and running now
• ...Meanwhile c1susaux lost its eth1 somehow. This made the slow values of 8 vertex sus all zero
-> Ran sudo /sbin/ifdown eth1 and sudo /sbin/ifup eth1 again on c1susaux ->  this resolved the issue
• c1psl
sudo systemctl start modbusIOC.service
-> c1psl epics is up and running now
• Prepared for the rebooting script
• Ran /opt/rtcds/caltech/c1/scripts/cds/rebootC1LSC.sh
• Rebooting was done successfully. All the suspensions looked free and healthy.
• Burtrestored c1susaux (used Apr 12 21:19 snapshot)

Hardware

• PSL laser / Xend AUX laser / Yend AUX laser were off -> turned on
• The PMC was immediately automatically locked.
• The main marconi was off -> forgot to turn on
• The end temp controllers for the SHG crystals were on but not enabled -> now enabled

RTS recovery ~ part 2

• FB: FB status of all the RTS models were still red
• Timing: c1x01/2/3/5 were 1 sec behind of FB and c1x04 was 2 sec behind
• -> Remedy:  https://nodus.ligo.caltech.edu:8081/40m/14349
• Software rebooting of FB
• Manually start the open-mx and mx services using
• sudo systemctl start open-mx.service
• sudo systemctl start mx.service
• Check that the system time returned by gpstime matches the gpstime reported by internet sources. e.g. http://leapsecond.com/java/gpsclock.htm
• Manually start the daqd processes using
sudo systemctl start daqd_*
• This made all the FB(FE) indicators green!
• Ran the reboot script again -> All green!

IMC recovery

• The IMC status was checked
• No autolocker, but it could be manually locked. i.e. MC1/2/3 were not so much misalignment
• Autolocker/Slow FSS recovery along with https://nodus.ligo.caltech.edu:8081/40m/15121
• sudo systemctl start MCautolocker.service
• sudo systemctl start FSSSlow.service
• Both of them failed to run
• Note by Gautam: The problem with the systemctl commands failing was that the NFS mount points weren’t mounted. Which in turn was because of the familiar /etc/resolv.conf problem. I added chiara to the namespace in this file, and then manually mounted the NFS mount points. This fixed the problem.
Now the IMC is locked and the autolocker is left running.

Burt restore

• Used Apr 12 21:19 snapshot
• c1psl
• c1alsepics/c1assepics/c1asxepics/c1asyepics
• c1aux/c1auxex/c1auxey/
• c1iscaux/c1susaux
• This made REFL and AS beams back to the CCDs. As has small fringes.
• Y arm has small IR flashes as well as green flashes.

JETSTOR recovery

• JETSTOR was beeping.
• Shutdown megatron
• Followed the instruction https://nodus.ligo.caltech.edu:8081/40m/13107
• This stopped beeping. Waiting for JETSTOR to come up -> In a minute, JETSTOR display became normal and all disks showed green.
• Bring megatron back up again

N2 bottle

• The left N2 bottle was empty. The right one had 1500PSI.
• Replaced the left bottle with the spare one in the room.
• Now the left one 2680PSI and the right one 1400PSI.

Closing

• Closed PSL/AUX laser shutters
• Turned off the lights in the lab, CTRL room, and the office.

Remaining Issues

• [done] MCAutoLocker / FSSSlow scripts are not running
• The PRM alignment slider has no effect (although the PRM is aligned…) -> SLOW DAQ frozen???
• JETSTOR is not mounted on megatron [gautam mounted Jetstor on megatron on 4/18 at 2pm]
15300   Tue Apr 7 15:30:40 2020 JonSummaryNoiseBudget40m noise budget migrated to pygwinc

In the past year, pygwinc has expanded to support not just fundamental noise calculations (e.g., quantum, thermal) but also any number of user-defined noises. These custom noise definitions can do anything, from evaluating an empirical model (e.g., electronics, suspension) to loading real noise measurements (e.g., laser AM/PM noise). Here is an example of the framework applied to H1.

Starting with the BHD review-era noises, I have set up the 40m pygwinc fork with a working noise budget which we can easily expand. Specific actions:

• Updated the 40m fork to the latest pygwinc version (while preserving the commit history).
• Added a directory ./CIT40m containing the 40m-specific noise budget files (created by GV).
• Added an ipython notebook CIT40m.ipynb at the root level showing how to generate a noise budget.
• Integrated our DAC and seismic noise estimators into pygwinc.
• Marked the old 40m NB repo as obsolete (last commit > 2 yrs ago). Many of these noise estimates are probably stale, but I will work with GV to identify which ones can be migrated.

I set up our fork in this way to keep the 40m separate from the main pygwinc code (i.e., not added to as a built-in IFO type). With the 40m code all contained within one root-level directory (with a 40m-specific name), we should now always be able to upgrade to the latest pygwinc without creating intractable merge conflicts.

5650   Tue Oct 11 15:19:17 2011 ranaHowToEnvironment40m map

The Kinemetrics dudes are going to visit us @ 1:45 tomorrow (Wednesday) to check out our stacks, seismos, etc.

I put these maps here on the elog since people are always getting lost trying to find the lab.

6058   Thu Dec 1 11:25:10 2011 steveUpdatePEM40m infrastructure holds up well in strong wind condition

Santa Anna wind speed was locked around 60 kmph last night on campus. The strongest in 30 years.  The lab hold up well. We did not lose  AC power either.

Threes and windows were blown out and  over on campus.

We have 4 sliding glass windows without "heavy-laser proved" inside protection.

We should plan to upgrade ALL  sliding glass windows with metal protection from the inside.The strongest in 30 years.

Attachment 1: santaannawind.png
Attachment 2: wind.png
340   Sun Feb 24 10:51:58 2008 tfFrogsEnvironment40m in phdcomics?

10507   Mon Sep 15 18:55:51 2014 ranaUpdateDAQ40m frames onto the cluster

Dan Kozak is rsync transferring /frames from NODUS over to the LDAS grid. He's doing this without a BW limit, but even so its going to take a couple weeks. If nodus seems pokey or the net connection to the outside world is too tight, then please let me and him know so that he can throttle the pipe a little.

10632   Wed Oct 22 21:06:33 2014 ChrisUpdateDAQ40m frames onto the cluster

 Quote: Dan Kozak is rsync transferring /frames from NODUS over to the LDAS grid. He's doing this without a BW limit, but even so its going to take a couple weeks. If nodus seems pokey or the net connection to the outside world is too tight, then please let me and him know so that he can throttle the pipe a little.

The recently observed daqd flakiness looks related to this transfer. It appears to still be ongoing:

nodus:~>ps -ef | grep rsync
controls 29089   382  5 13:39:20 pts/1   13:55 rsync -a --inplace --delete --exclude lost+found --exclude .*.gwf /frames/trend
controls 29100   382  2 13:39:43 pts/1    9:15 rsync -a --delete --exclude lost+found --exclude .*.gwf /frames/full/10975 131.
controls 29109   382  3 13:39:43 pts/1    9:10 rsync -a --delete --exclude lost+found --exclude .*.gwf /frames/full/10978 131.
controls 29103   382  3 13:39:43 pts/1    9:14 rsync -a --delete --exclude lost+found --exclude .*.gwf /frames/full/10976 131.
controls 29112   382  3 13:39:43 pts/1    9:18 rsync -a --delete --exclude lost+found --exclude .*.gwf /frames/full/10979 131.
controls 29099   382  2 13:39:43 pts/1    9:14 rsync -a --delete --exclude lost+found --exclude .*.gwf /frames/full/10974 131.
controls 29106   382  3 13:39:43 pts/1    9:13 rsync -a --delete --exclude lost+found --exclude .*.gwf /frames/full/10977 131.
controls 29620 29603  0 20:40:48 pts/3    0:00 grep rsync



Diagnosing the problem:

I logged into fb and ran "top". It said that fb was waiting for disk I/O ~60% of the time (according to the "%wa" number in the header). There were 8 nfsd (network file server) processes running with several of them listed in status "D" (waiting for disk). The daqd logs were ending with errors like the following suggesting that it couldn't keep up with the flow of data:

[Wed Oct 22 18:58:35 2014] main profiler warning: 1 empty blocks in the buffer
[Wed Oct 22 18:58:36 2014] main profiler warning: 0 empty blocks in the buffer
GPS time jumped from 1098064730 to 1098064731


This all pointed to the possibility that the file transfer load was too heavy.

The following configuration changes were applied on fb.

Edited /etc/conf.d/nfs to reduce the number of nfsd processes from 8 to 1:

OPTS_RPC_NFSD="1"


(was "8")

Ran "ionice" to raise the priority of the framebuilder process (daqd):

controls@fb /opt/rtcds/rtscore/trunk/src/daqd 0$sudo ionice -c 1 -p 10964  And to reduce the priority of the nfsd process: controls@fb /opt/rtcds/rtscore/trunk/src/daqd 0$ sudo ionice -c 2 -p 11198


I also tried punishing nfsd with an even lower priority ("-c 3"), but that was causing the workstations to lag noticeably.

After these changes the %wa value went from ~60% to ~20%, and daqd seems to die less often, but some further throttling may still be in order.

2315   Mon Nov 23 17:53:08 2009 JenneUpdateComputers40m frame builder backup acting funny

As part of the fb40m restart procedure (Sanjit and I were restarting it to add some new channels so they can be read by the OAF model), I checked up on how the backup has been going.  Unfortunately the answer is: not well.

Alan imparted to me all the wisdom of frame builder backups on September 28th of this year.  Except for the first 2 days of something having gone wrong (which was fixed at that time), the backup script hasn't thrown any errors, and thus hasn't sent any whiny emails to me.  This is seen by opening up /caltech/scripts/backup/rsync.backup.cumlog , and noticing that  after October 1, 2009, all of the 'errorcodes' have been zero, i.e. no error (as opposed to 'errorcode 2' when the backup fails).

However, when you ssh to the backup server to see what .gwf files exist, the last one is at gps time 941803200, which is Nov 9 2009, 11:59:45 UTC.  So, I'm not sure why no errors have been thrown, but also no backups have happened. Looking at the rsync.backup.log file, it says 'Host Key Verification Failed'.  This seems like something which isn't changing the errcode, but should be, so that it can send me an email when things aren't up to snuff.  On Nov 10th (the first day the backup didn't do any backing-up), there was a lot of Megatron action, and some adding of StochMon channels.  If the fb was restarted for either of these things, and the backup script wasn't started, then it should have had an error, and sent me an email.  Since any time the frame builder's backup script hasn't been started properly it should send an email, I'm going to go ahead and blame whoever wrote the scripts, rather than the Joe/Pete/Alberto team.

Since our new raid disk is ~28 days of local storage, we won't have lost anything on the backup server as long as the backup works tonight (or sometime in the next few days), because the backup is an rsync, so it copies anything which it hasn't already copied.  Since the fb got restarted just now, hopefully whatever funny business (maybe with the .agent files???) will be gone, and the backup will work properly.

I'll check in with the frame builder again tomorrow, to make sure that it's all good.

2322   Tue Nov 24 16:06:45 2009 JenneUpdateComputers40m frame builder backup acting funny

 Quote: As part of the fb40m restart procedure (Sanjit and I were restarting it to add some new channels so they can be read by the OAF model), I checked up on how the backup has been going.  Unfortunately the answer is: not well. I'll check in with the frame builder again tomorrow, to make sure that it's all good.

All is well again in the world of backups.  We are now up to date as of ~midnight last night.

2330   Wed Nov 25 11:10:05 2009 JenneUpdateComputers40m frame builder backup acting funny

Quote:

 Quote: As part of the fb40m restart procedure (Sanjit and I were restarting it to add some new channels so they can be read by the OAF model), I checked up on how the backup has been going.  Unfortunately the answer is: not well. I'll check in with the frame builder again tomorrow, to make sure that it's all good.

All is well again in the world of backups.  We are now up to date as of ~midnight last night.

Backup Fail.  At least this time however, it threw the appropriate error code, and sent me an email saying that it was unhappy.  Alan said he was going to check in with Stuart regarding the confusion with the ssh-agent.  (The other day, when I did a ps -ef | grep agent, there were ~5 ssh-agents running, which could have been then cause of the unsuccessful backups without telling me that they failed.  The main symptom is that when I first restart all of the ssh-agent stuff, according to the directions in the Restart fb40m Procedures, I can do a test ssh over to ldas-cit, to see what frames are there.  If I log out of the frame builder and log back in, then I can no longer ssh to ldas-cit without a password.  This shouldn't happen....the ssh-agent is supposed to authenticate the connection so no passwords are necessary.)

I'm going to restart the backup script again, and we'll see how it goes over the long weekend.

13404   Sat Oct 28 00:36:26 2017 gautamUpdateCDS40m files backup situation - ddrescue

None of the 3 dd backups I made were bootable - at boot, selecting the drive put me into grub rescue mode, which seemed to suggest that the /boot partition did not exist on the backed up disk, despite the fact that I was able to mount this partition on a booted computer. Perhaps for the same reason, but maybe not.

After going through various StackOverflow posts / blogs / other googling, I decided to try cloning the drives using ddrescue instead of dd.

This seems to have worked for nodus - I was able to boot to console on the machine called rosalba which was lying around under my desk. I deliberately did not have this machine connected to the martian network during the boot process for fear of some issues because of having multiple "nodus"-es on the network, so it complained a bit about starting the elog and other network related issues, but seems like we have a plug-and-play version of the nodus root filesystem now.

chiara and fb1 rootfs backups (made using ddrescue) are still not bootable - I'm working on it.

Nov 6 2017: I am now able to boot the chiara backup as well - although mysteriously, I cannot boot it from the machine called rosalba, but can boot it from ottavia. Anyways, seems like we have usable backups of the rootfs of nodus and chiara now. FB1 is still a no-go, working on it.

 Quote: Looks to have worked this time around. controls@fb1:~ 0$sudo dd if=/dev/sda of=/dev/sdc bs=64K conv=noerror,sync 33554416+0 records in 33554416+0 records out 2199022206976 bytes (2.2 TB) copied, 55910.3 s, 39.3 MB/s You have new mail in /var/mail/controls I was able to mount all the partitions on the cloned disk. Will now try booting from this disk on the spare machine I am testing in the office area now. That'd be a "real" test of if this backup is useful in the event of a disk failure. Attachment 1: 415E2F09-3962-432C-B901-DBCB5CE1F6B6.jpeg Attachment 2: BFF8F8B5-1836-4188-BDF1-DDC0F5B45B41.jpeg 13262 Mon Aug 28 16:20:00 2017 gautamUpdateCDS40m files backup situation ## This elog is meant to summarize the current backup situation of critical 40m files. What are the critical filesystems? I've also indicated the size of these disks and the volume currently used, and the current backup situation. ### Name ### Disk Usage ### Description / remarks ### Current backup status FB1 root filesystem 1.7TB / 2TB • FB1 is the machine that hosts the diskless root for the front end machines • Additionally, it runs the daqd processes which write data from realtime models into frame files Not backed up /frames up to 24TB • This is where the frame files are written to • Need to setup a wiper script that periodically clears older data so that the disk doesn't overflow. Not backed up LDAS pulls files from nodus daily via rsync, so there's no cron job for us to manage. We just allow incoming rsync. Shared user area 1.6TB / 2TB • /home/cds on chiara • This is exported over NFS to 40m workstations, FB1 etc. • Contains user directories, scripts, realtime models etc. Local backup on /media/40mBackup on chiara via daily cronjob Remote backup to ldas-cit.ligo.caltech.edu::40m/cvs via daily cronjob on nodus Chiara root filesystem 11GB / 440GB • This is the root filesystem for chiara • Contains nameserver stuff for the martian network, responsible for rsyncing /home/cds Not backed up Megatron root filesystem 39GB / 130GB • Boot disk for megatron, which is our scripts machine • Runs MC autolocker, FSS loops etc. • Also is the nds server for facilitating data access from outside the martian network Not backed up Nodus root filesystem 77GB / 355GB • This is the boot disk for our gateway machine • Hosts Elog, svn, wikis • Supposed to be responsible for sending email alerts for NFS disk usage and vacuum system N2 pressure Not backed up JETSTOR RAID Array 12TB / 13TB • Old /frames • Archived frames from DRFPMI locks • Long term trends Currently mounted on Megatron, not backed up. Then there is Optimus, but I don't think there is anything critical on it. So, based on my understanding, we need to back up a whole bunch of stuff, particularly the boot disks and root filesystems for Chiara, Megatron and Nodus. We should also test that the backups we make are useful (i.e. we can recover current operating state in the event of a disk failure). Please edit this elog if I have made a mistake. I also don't have any idea about whether there is any sort of backup for the slow computing system code. 13263 Mon Aug 28 17:13:57 2017 ericqUpdateCDS40m files backup situation In addition to bootable full disk backups, it would be wise to make sure the important service configuration files from each machine are version controlled in the 40m SVN. Things like apache files on nodus, martian hosts and DHCP files on chiara, nds2 configuration and init scripts on megatron, etc. This can make future OS/hardware upgrades easier too. 13332 Tue Sep 26 15:55:20 2017 gautamUpdateCDS40m files backup situation ### Backups of the root filesystems of chiara and nodus are underway right now. I am backing them up to the 1 TB LaCie external hard drives we recently acquired. I first initialized the drives by hooking them up to my computer and running the setup.app file. After this, plugging the drive into the respective machine and running lsblk, I was able to see the mount point of the external drive. To actually initialize the backup, I ran the following command from a tmux session called ddBackupLaCie: sudo dd if=/dev/sda of=/dev/sdb bs=64K conv=noerror,sync Here, /dev/sda is the disk with the root filesystem, and /dev/sdb is the external hard-drive. The installed version of dd is 8.13, and from version 8.21 onwards, there is a progress flag available, but I didn't want to go through the exercise of upgrading coreutils on multiple machines, so we just have to wait till the backup finishes. We also wanted to do a backup of the root of FB1 - but I'm not sure if dd will work with the external hard drive, because I think it requires the backup disk size (for us, 1TB) to be >= origin disk size (which on FB1, according to df -h, is 2TB). Unsure why the root filesystem of FB is so big, I'm checking with Jamie what we expect it to be. Anyways we have also acquired 2TB HGST SATA drives, which I will use if the LaCie disks aren't an option. 13339 Thu Sep 28 10:33:46 2017 gautamUpdateCDS40m files backup situation After consulting with Jamie, we reached the conclusion that the reason why the root of FB1 is so huge is because of the way the RAID for /frames is setup. Based on my googling, I couldn't find a way to exclude the nfs stuff while doing a backup using dd, which isn't all that surprising because dd is supposed to make an exact replica of the disk being cloned, including any empty space. So we don't have that flexibility with dd. The advantage of using dd is that if it works, we have a plug-and-play clone of the boot disk and root filesystem which we can use in the event of a hard-disk failure. 1. One option would be to stop all the daqd processes, unmount /frames, and then do a dd backup of the true boot disk and root filesystem. 2. Another option would be to use rsync to do the backup - this way we can selectively copy the files we want and ignore the nfs stuff. I suspect this is what we will have to do for the second layer of backup we have planned, which will be run as a daily cron job. But I don't think this approach will give us a plug-and-play replacement disk in the event of a disk failure. 3. Third option is to use one of the 2TB HGST drives, and just do a dd backup - some of this will be /frames, but that's okay I guess. I am trying option 3 now. dd however does requrie that the destination drive size be >= source drive size - I'm not sure if this is true for the HGST drives. lsblk suggests that the drive size is 1.8TB, while the boot disk, /dev/sda, is 2TB. Let's see if it works. Backup of chiara is done. I checked that I could mount the external drive at /mnt and access the files. We should still do a check of trying to boot from the LaCie backup disk, need another computer for that. nodus backup is still not complete according to the console - there is no progress indicator so we just have to wait I guess. Quote: ### Backups of the root filesystems of chiara and nodus are underway right now. I am backing them up to the 1 TB LaCie external hard drives we recently acquired. We also wanted to do a backup of the root of FB1 - but I'm not sure if dd will work with the external hard drive, because I think it requires the backup disk size (for us, 1TB) to be >= origin disk size (which on FB1, according to df -h, is 2TB). Unsure why the root filesystem of FB is so big, I'm checking with Jamie what we expect it to be. Anyways we have also acquired 2TB HGST SATA drives, which I will use if the LaCie disks aren't an option. 13340 Thu Sep 28 11:13:32 2017 jamieUpdateCDS40m files backup situation  Quote: After consulting with Jamie, we reached the conclusion that the reason why the root of FB1 is so huge is because of the way the RAID for /frames is setup. Based on my googling, I couldn't find a way to exclude the nfs stuff while doing a backup using dd, which isn't all that surprising because dd is supposed to make an exact replica of the disk being cloned, including any empty space. So we don't have that flexibility with dd. The advantage of using dd is that if it works, we have a plug-and-play clone of the boot disk and root filesystem which we can use in the event of a hard-disk failure. One option would be to stop all the daqd processes, unmount /frames, and then do a dd backup of the true boot disk and root filesystem. Another option would be to use rsync to do the backup - this way we can selectively copy the files we want and ignore the nfs stuff. I suspect this is what we will have to do for the second layer of backup we have planned, which will be run as a daily cron job. But I don't think this approach will give us a plug-and-play replacement disk in the event of a disk failure. Third option is to use one of the 2TB HGST drives, and just do a dd backup - some of this will be /frames, but that's okay I guess. This is not quite right. First of all, /frames is not NFS. It's a mount of a local filesystem that happens to be on a RAID. Second, the frames RAID is mounted at /frames. If you do a dd of the underlying block device (in this case /dev/sda*, you're not going to copy anything that's mounted on top of it. What i was saying about /frames is that I believe there is data in the underlying directory /frames that the frames RAID is mounted on top of. In order to not get that in the copy of /dev/sda4 you would need to unmount the frames RAID from /frames, and delete everything from the /frames directory. This would not harm the frames RAID at all. But it doesn't really matter because the backup disk has space to cover the whole thing so just don't worry about it. Just dd /dev/sda to the backup disk and you'll just be copying the root filesystem, which is what we want. 13342 Thu Sep 28 23:47:38 2017 gautamUpdateCDS40m files backup situation The nodus backup too is now complete - however, I am unable to mount the backup disk anywhere. I tried on a couple of different machines (optimus, chiara and pianosa), but always get the same error: mount: unknown filesystem type 'LVM2_member' The disk itself is being recognized, and I can see the partitions when I run lsblk, but I can't get the disk to actually mount. Doing a web-search, I came across a few blog posts that look like the problem can be resolved using the vgchange utility - but I am not sure what exactly this does so I am holding off on trying. To clarify, I performed the cloning by running sudo dd if=/dev/sda of=/dev/sdb bs=64K conv=noerror,sync in a tmux session on nodus (as I did for chiara and FB1, latter backup is still running). 13345 Fri Sep 29 11:07:16 2017 gautamUpdateCDS40m files backup situation The FB1 dd backup process seems to have finished too - but I got the following message: dd: error writing ‘/dev/sdc’: No space left on device 30523666+0 records in 30523665+0 records out 2000398934016 bytes (2.0 TB) copied, 50865.1 s, 39.3 MB/s Running lsblk shows the following: controls@fb1:~ 32$ lsblk NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT sdb      8:16   0 23.5T  0 disk └─sdb1   8:17   0 23.5T  0 part /frames sda      8:0    0    2T  0 disk ├─sda1   8:1    0  476M  0 part /boot ├─sda2   8:2    0 18.6G  0 part /var ├─sda3   8:3    0  8.4G  0 part [SWAP] └─sda4   8:4    0    2T  0 part / sdc      8:32   0  1.8T  0 disk ├─sdc1   8:33   0  476M  0 part ├─sdc2   8:34   0 18.6G  0 part ├─sdc3   8:35   0  8.4G  0 part └─sdc4   8:36   0  1.8T  0 part

While I am able to mount /dev/sdc1, I can't mount /dev/sdc4, for which I get the error message

controls@fb1:~ 0$sudo mount /dev/sdc4 /mnt/HGSTbackup/ mount: wrong fs type, bad option, bad superblock on /dev/sdc4, missing codepage or helper program, or other error  In some cases useful info is found in syslog - try dmesg | tail or so. Looking at dmesg, it looks like this error is related to the fact that we are trying to clone a 2TB disk onto a 1.8TB disk - it complains about block size exceeding device size. ## So if we either have to get a larger disk (4TB?) to do the dd backup, or do the backing up some other way (e.g. unmount /frames RAID, delete everything in /frames, and then do dd, as Jamie suggested). If I understand correctly, unmounting /frames RAID will require that we stop all the daqd processes for the duration of the dd backup  Quote: sudo dd if=/dev/sda of=/dev/sdb bs=64K conv=noerror,sync in a tmux session on nodus (as I did for chiara and FB1, latter backup is still running). ## Edit: unmounting /frames won't help, since dd makes a bit for bit copy of the drive being cloned. So we need a drive with size that is >= that of the drive we are trying to clone. On FB1, this is /dev/sda, which has a size of 2TB. The HGST drive we got has an advertised size of 2TB, but looks like actually only 1.8TB is available. So I think we need to order a 4TB drive. 13361 Thu Oct 5 13:58:26 2017 gautamUpdateCDS40m files backup situation The 4TB HGST drives have arrived. I've started the FB1 dd backup process. Should take a day or so.  Quote: Edit: unmounting /frames won't help, since dd makes a bit for bit copy of the drive being cloned. So we need a drive with size that is >= that of the drive we are trying to clone. On FB1, this is /dev/sda, which has a size of 2TB. The HGST drive we got has an advertised size of 2TB, but looks like actually only 1.8TB is available. So I think we need to order a 4TB drive. 13364 Fri Oct 6 12:46:17 2017 gautamUpdateCDS40m files backup situation Looks to have worked this time around. controls@fb1:~ 0$ sudo dd if=/dev/sda of=/dev/sdc bs=64K conv=noerror,sync 33554416+0 records in 33554416+0 records out 2199022206976 bytes (2.2 TB) copied, 55910.3 s, 39.3 MB/s You have new mail in /var/mail/controls

I was able to mount all the partitions on the cloned disk. Will now try booting from this disk on the spare machine I am testing in the office area now. That'd be a "real" test of if this backup is useful in the event of a disk failure.

 Quote: The 4TB HGST drives have arrived. I've started the FB1 dd backup process. Should take a day or so.

3869   Fri Nov 5 15:20:18 2010 josephb, alexSummaryCDS40m computer slow down solved

Problem:

The 40m computers were responding sluggishly yesterday, to the point of being unusable.

Cause:

The mx_stream code running on c1iscex (the X end suspension control computer) went crazy for some reason.  It was constantly writing to a log file in /cvs/cds/rtcds/caltech/c1/target/fb/192.168.113.80.log.  In the past 24 hours this file had grown to approximately 1 Tb in size. The computer had been turned back on yesterday after having reconnected its IO chassis, which had been moved around last week for testing purposes - specifically plugging the c1ioo IO chassis in to it to confirm it had timing problems.

Current Status:

The mx_stream code was killed on c1iscex and the 1 Tb file removed.

Computers are now more usable.

We still need to investigate exactly what caused the code to start writing to the log file non-stop.

Update Edit:

Alex believes this was due to a missing entry in the /diskless/root/etc/hosts file on the fb machine.  It didn't list the IP and hostname for the c1iscex machine.  I have now added it.  c1iscex had been added to the /etc/dhcp/dhcpd.conf file on fb, which is why it was able to boot at all in the first place.  With the addition of the automatic start up of mx_streams in the past week by Alex, the code started, but without the correct ip address in the hosts file, it was getting confused about where it was running and constantly writing errors.

Future:

When adding a new FE machine, add its IP address and its hostname to the /diskless/root/etc/hosts file on the fb machine.

3872   Fri Nov 5 21:49:12 2010 ranaSummaryCDS40m computer slow down solved

 Quote: Problem: The 40m computers were responding sluggishly yesterday, to the point of being unusable. Cause: The mx_stream code running on c1iscex (the X end suspension control computer) went crazy for some reason.  It was constantly writing to a log file in /cvs/cds/rtcds/caltech/c1/target/fb/192.168.113.80.log.  In the past 24 hours this file had grown to approximatel

The moral of the story is, PUT THINGS IN THE ELOG. This wild process is one of those things where people say 'this won't effect anything', but in fact it wastes several hours of time.

3877   Sat Nov 6 16:13:14 2010 ranaSummaryCDS40m computer slow down solved

As part of the effort to debug what was happening with the slow computers, I disabled the auto MEDM snapshots process that Yoichi/Kakeru setup some long time ago:

https://nodus.ligo.caltech.edu:30889/medm/screenshot.html

We have to re-activate it now that the MEDM screen locations have been changed. To do this, we have to modify the crontab on nodus and also the scripts that the cron is calling. I would prefer to run this cron on some linux machine since nodus starts to crawl whenever we run ImageMagick stuff.

Also, we should remember to start moving the old target/ directories into the new area. All of the slow VME controls are still not in opt/rtcds/.

3106   Wed Jun 23 15:15:53 2010 josephbSummaryComputers40m computer security issue from last night and this morning

The following is not 100% accurate, but represents my understanding of the events currently.  I'm trying to get a full description from Christian and will hopefully be able to update this information later today.

Last night around 7:30 pm, Caltech detected evidence of computer virus located behind a linksys router with mac address matching our NAT router, and at the IP 131.215.114.177.  We did not initially recognize the mac address as the routers because the labeled mac address was off by a digit, so we were looking for another old router for awhile.  In addition, pings to 131.215.114.177 were not working from inside or outside of the martian network, but the router was clearly working.

However, about 5 minutes after Christian and Mike left, I found I could ping the address.  When I placed the address into a web browser, the address brought us to the control interface for our NAT router (but only from the martian side, from the outside world it wasn't possible to reach it).

They turned logging on the router (which had been off by default) and started monitoring the traffic for a short time.  Some unusual IP addresses showed up, and Mike said something about someone trying to IP spoof warning coming up.  Something about a file sharing port showing up was briefly mentioned as well.

The outside IP address was changed to 131.215.115.189 and dhcp which apparently was on, was turned off.  The password was changed and is in the usual place we keep router passwords.

Update: Christian said Mike has written up a security report and that he'll talk to him tomorrow and forward the relevant information to me.  He notes there is possibly an infected laptop/workstation still at large.  This could also be a personal laptop that was accidently connected to the martian network.  Since it was found to be set to dhcp, its possible a laptop was connected to the wrong side and the user might not have realized this.

6733   Thu May 31 17:47:25 2012 SureshOmnistructureGeneral40m Wireless Network

Mike Pedraza came by today to install a new wireless network router configured for the 40m lab network.  It has a 'secret' SSID i.e. not meant for public use outside the lab.  You can look up the password and network name on the rack.  Pictures below show the location of the labels.

6741   Fri Jun 1 10:00:03 2012 steveOmnistructureGeneral40m Wireless Network

 Quote: Mike Pedraza came by today to install a new wireless network router configured for the 40m lab network.  It has a 'secret' SSID i.e. not meant for public use outside the lab.  You can look up the password and network name on the rack.  Pictures below show the location of the labels.

Mike P swapped in a new network router Linksys E1000

3072   Sat Jun 12 19:41:04 2010 AlbertoUpdateLocking40m Upgrade Optickle Model

I wrote down the settings according to which I tuned the optickle model of the 40m Upgrade.

Basically I set it so that:

1. PRC alone anti-resonant for the carrier and resonant for both sidebands
2. SRC alone resonant for the carrier and resonant for the f2 sideband

In this way when the carrier becomes resonant in the arms we have:

1. carrier resonant in PRC and anti-resonant in SRC
2. f1 resonant in PRC and non resonant in SRC
3. f2 resonant in SRC

The DARM offset for DC readout is optional, and doesn't change those conditions.

I also plotted the carrier and the sideband's circulating power for both recycling cavities.

I'm attaching a file containing more detailed explanations of what I said above. It also contains the plots of field powers, and transfer functions from DARM to the dark port. I think they don't look quite right. There seems to be something wrong.

Valera thought of fixing the problem, removing the 180 degree offset on the SRM, which is what makes the sideband rather than the carrier resonant in SRC. In his model the carrier becomes resonant and the sideband anti-resonant. I don't think that is correct.

The resonant-carrier case is also included in the attachment (the plots with SRMoff=0 deg). In the plots the DARM offset is always zero.

I'm not sure why the settings are not producing the expected transfer functions.

Attachment 1: optickleIFOworkingpoint.pdf
3074   Sun Jun 13 08:28:44 2010 valeraUpdateLocking40m Upgrade Optickle Model

In my calculation of the digital filters of the optical transfer functions the carrier light is resonant in coupled cavities and the sidebands are resonant in recycling cavities (provided that macroscopic lengths are chosen correctly which I assumed).

3075   Mon Jun 14 07:57:07 2010 albertoUpdateLocking40m Upgrade Optickle Model

 Quote: In my calculation of the digital filters of the optical transfer functions the carrier light is resonant in coupled cavities and the sidebands are resonant in recycling cavities (provided that macroscopic lengths are chosen correctly which I assumed).

Carrier and SB (f2) shouldn't be resonant at the same time in the SRC-arms coupled cavity. No additional filtering of the GW signal is wanted.

The SRC macroscopic length is chosen to be = c / f2 - rather than = [ (n+1/2) c / (2*f2) ] - accordingly to that purpose.

3079   Tue Jun 15 21:28:44 2010 albertoUpdateLocking40m Upgrade Optickle Model

Quote:

 Quote: In my calculation of the digital filters of the optical transfer functions the carrier light is resonant in coupled cavities and the sidebands are resonant in recycling cavities (provided that macroscopic lengths are chosen correctly which I assumed).

Carrier and SB (f2) shouldn't be resonant at the same time in the SRC-arms coupled cavity. No additional filtering of the GW signal is wanted.

The SRC macroscopic length is chosen to be = c / f2 - rather than = [ (n+1/2) c / (2*f2) ] - accordingly to that purpose.

I calculated the frequency of the double cavity pole for the 40m SRC-arm coupled cavity.

w_cc = (1 + r_srm)/(1- r_srm) * w_c

where w_c is the arm cavity pole angular frequency [w_c = w_fsr * (1-r_itm * r_etm)/sqrt(r_itm*r_etm) ]

I found the pole at about 160KHz. This number coincides with what I got earlier with my optickle model configured and tuned as I said in my previous entry. See attachments for plots of transfer functions with 0 and 10pm DARM offsets, respectively.

I think  the resonance at about 20 Hz that you can see in the case with non-zero DARM offset, is due to radiation pressure. Koji suggested that I could check the hypothesis by changing either the mirrors' masses or the input power to the interferometer. When I did it frequency and qualty factor of the resonance changed, as you would expect for a radiation pressure effect.

Independently, Jan also calculated the pole frequency of the transfer function DARM / ASQ2 as we would expect it for the SRC-coupled cavity. He also found the pole at about 160KHz. I'm attaching the plot with the transfer function he calculated.
He also said that the little bump at the pole frequency is OK considering that our signal recycling cavity is not much shorter than the arms.

This gave me more confidence about my optickle model of the 40m. This is quite comforting since I used that model other times in the past to calculate several things (i.e. effects of higher unwanted harmonics from the oscillator, or, recently, the power at the ports due to the SB resonating in the arms).

I don't know anymore what Valera said that wasn't right.
Also, as he said, he set it for the carrier to be resonant in the SRC-arms couple cavity. But that is not our case.
Attachment 1: allTransferFunctions_DARMoff_0.pdf
Attachment 2: allTransferFunctions_DARM2AS_10pmDARMoffset.pdf
Attachment 3: Jan_DARM2AS.pdf
2044   Fri Oct 2 17:00:06 2009 AlbertoUpdateGeneral40m Update - Requirements on the 5x Frequency Multiplier

Here's the gist of the requirements on the 5x frequency multiplier for the upgrade (see attachemnt - despite the preview down here in the elog, they're 3 pages).

An extended version is available on the wiki.

A more complete document is under work and will soon be available on the wiki as well.

Attachment 1: DesignOfTheMultiplier1-14-15.pdf
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.

6222   Wed Jan 25 15:04:41 2012 JenneBureaucracySAFETY40m SOS supplies moved off of cleanroom flow bench

Bob, Callum and Daphen noted that our keeping a JDSU HeNe (max power <4mW) is against somebody's SOP.  So I cleared everything that relates to 40m SOS suspending to the bottom shelf of the 2nd cabinet in the cleanroom (the back set of cabinets nearest the flow benches).  The door has a nifty label.  Things that are in there include:

HeNe

HeNe mount

QPD and micrometer mount

microscope and micrometer mount

iris

Al beam block

Magnet gluing fixture

dumbbell gluing fixture

The electronics that we use (HeNe's power supply, 'scope, QPD readout) are still on the roll-y thing under the flow bench.

6974   Fri Jul 13 15:49:38 2012 yutaBureaucracyGeneral40m Priority Action Items

These are all priority action items need to be done before I come back (in mid-September).
BE PREPARED FOR THE FULL LOCK!

NEXT VENT:
- Prepare and install tip-tilts -JAMIE
- Adjust IP-ANG -JAMIE, JENNE, KOJI
- Make sure there's no clipping. Start from MC centering -JAMIE, JENNE, KOJI

ASS/A2L:
- Make ASS and A2L work -JENNE, JAMIE
- Better MC spot position measurement script(see the last sentence in elog #6892) -JENNE
- Daily beam spot measurements for IFO, just like MC -JENNE
- ASS for green using PZT steering mirrors on end table -JENNE
- Modeling of phase tracking ALS -JAMIE

ALS:
- PZT mounts for PSL and ALS beams -JENNE, KOJI
- Add temperature sensors for end lasers to CDS slow channels -JENNE
- Put green trans camera, GTRY PD, and GTRX PD on PSL table -JENNE
- Better beat box; include comparators, frequency dividers, and whitening filters -JAMIE, KOJI
- Adjust servo gain/filters of end green PDH lock (reduce frequency noise) -JENNE
- Add on/off switch, gain adjuster, etc to CDS for end green PDH lock -JENNE, JAMIE

PRC:
- Find why and reduce 3 Hz motion -JENNE
- Simulation of PRMI with clipping -YUTA
- Alignment tolerance of PRMI -YUTA

15323   Sat May 9 17:01:08 2020 YehonathanUpdateLoss Measurement40m Phase maps loss estimation
I took the phase maps of the 40m X arm mirrors and calculated what is the loss of a gaussian beam due to a single bounce. I did it by simply calculating 1 - (overlap integral)^2 where the overlap is between an input Gaussian mode (calculated from the parameters of the cavity. Waist ~ 3.1mm) and the reflected beam (Gaussian imprinted with the phase map). The phase maps were prepared using PyKat surfacemap class to remove a flat surface, spherical surface, centering, etc. (Attachments 3, 4)

I calculated the loss map (Attachments 1,2: ~ 4X4 mm for ITM, 3X3mm for ETM) by shifting the beam around the phase map. It can be seen that there is a great variation in the loss: some areas are < 10 ppm some are > 80 ppm.

For the ITM (where the beam waist is) the average loss is ~ 23ppm and for the ETM its ~ 61ppm due to the enlarged beam. The ETM case is less physical because it takes a pure gaussian as an input where in reality the beam first interacts with the ITM.

I plan to do some first-order perturbation theory to include the cavity effects. I expect that the losses will be slightly lower due to HOMs not being completely lost, but who knows.

Attachment 1: ITMX_Loss_Map.pdf
Attachment 2: ETMX_Loss_Map.pdf
Attachment 3: ITMX_Phase_Map_(nm).pdf
Attachment 4: ETMX_Phase_Map_(nm).pdf
15329   Wed May 13 15:13:11 2020 YehonathanUpdateLoss Measurement40m Phase maps loss estimation

Koji pointed out during the group meeting that I should compensate for local tilt when I move the beam around the mirror for calculating the loss map.

So I did.

Also, I made a mistake earlier by calculating the loss map for a much bigger (X7) area than what I thought.

Both these mistakes made it seem like the loss is very inhomogeneous across the mirror.

Attachment 1 and 2 show the corrected loss maps for ITMX and ETMX respectively.

The loss now seems much more reasonable and homogeneous and the average total arm loss sums up to ~ 22ppm which is consistent with the after-cleaning arm loss measurements.

Attachment 1: ITMX_Loss_Map.pdf
Attachment 2: ETMX_Loss_Map.pdf
15332   Thu May 14 12:21:56 2020 YehonathanUpdateLoss Measurement40m Phase maps loss estimation

I finished calculating the X Arm loss using first-order perturbation theory. I will post the details of the calculation later.

I calculated loss maps of ITM and ETM (attachments 1,2 respectively). It's a little different than previous calculation because now both mirrors are considered and total cavity loss is calculated. The map is calculated by fixing one mirror and shifting the other one around.

The losin total is pretty much the same as calculated before using a different method. At the center of the mirror, the loss is 21.8ppm which is very close to the value that was calculated.

Next thing is to try SIS.

Attachment 1: ITMX_Loss_Map_Perturbation_Theory.pdf
Attachment 2: ETMX_Loss_Map_Perturbation_Theory(1).pdf
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