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ID Date Authorup Type Category Subject
  15060   Mon Dec 2 20:18:18 2019 ranaUpdateALSEY uPDH post mixer LPF

                   filter Q seems too high,

but what precisely is the proper way to design the IF filter?

   seems like we should be able to do it using math instead of feelins

                              Izumi made this one so maybe he has an algorythym

  15065   Tue Dec 3 14:52:13 2019 ranaUpdateIMCQ Measurement of Test Masses

crying

Quote:

[Yehonathan, Gavin]

  1. Lock IMC
  2. Lock one of the arms (only) using the IR PDH signal feeding back to an ETM.
  3. Excite the ITM using the SR785 near 28.8 kHz
  4. Look for the resulting peak using the SR785 spectra of the POX or POY error signal from the demod board
  5. Based on the calibrated noise level of the POX/POY, estimate what the SNR will be of the internal mode peak.
  15067   Tue Dec 3 20:32:37 2019 ranaOmnistructureDAQNDS2 situation

Recently, accordian to Gautam, the NDS2 server has been dying on Megatron ~daily or weekly. The prescription is to restart the server.

  1. I could find no instructions (that work) in the elog or wiki. We must remove the misleading entries from the wiki and update it with whatever works as of today.
  2. There is a line (which has been commented out) in the Megatron crontab which is close to the right command, but it has the wrong path.
  3. Running the command from the CRON (/home/nds2mgr/nds2-megatron/test_restart), gives several errrors.
  4. when I run the init.d command which is in the script, it seems to run fine
  5. the server then takes several minutes to get itself together; i.e. just because it is running doesn't mean that you can get data. I recommend waiting 5-10 minutes.

Also, megatron is running Ubuntu 12 !! Let's decide on a day to upgrade it to a Debian 18ish....word from Rolf is that Scientific Linux is fading out everywhere, so Debian is the new operating system for all conformists.

Attachment 1: getData.py
#!/usr/bin/env python
# this function gets some data (from the 40m) and saves it as
# a .mat file for the matlabs
# Ex. python -O getData.py


from scipy.io import savemat,loadmat
import scipy.signal as sig
from astropy.time import Time
import nds2
... 116 more lines ...
Attachment 2: chanlist.txt
PEM-SEIS_BS_X_OUT_DQ
PEM-SEIS_BS_Y_OUT_DQ
PEM-SEIS_BS_Z_OUT_DQ
PEM-SEIS_EX_X_OUT_DQ
PEM-SEIS_EX_Y_OUT_DQ
PEM-SEIS_EX_Z_OUT_DQ
PEM-SEIS_EY_X_OUT_DQ
PEM-SEIS_EY_Y_OUT_DQ
PEM-SEIS_EY_Z_OUT_DQ
  15082   Fri Dec 6 17:49:46 2019 ranaSummaryPEMJump test of seismometers: EX needs recentering

Yehonathan, please center the EX seismometer.

The attached PDF shows the seismometer signals (I'm assuming that they're already calibrated into microns/s) during the lab tour for the art students on 11/1. The big spike which I've zoomed in on shows the time when we were in the control room and we all jumped up at the same time. There were approximately 15 students each with a mass of ~50-70 kg. I estimate that out landing times were all sync'd to within ~0.1 s.

Attachment 1: Seismometers.pdf
Seismometers.pdf
Attachment 2: src.tgz
  15083   Sun Dec 8 20:15:41 2019 ranaSummaryPEMJump test of seismometers: EX needs recentering

I have re-centered the EX (and EY) seismometers. They are Guralp CMG40-T, and have no special centering procedure except cycling the power a few times. I turned off the power on their interface box, then waited 10s before turning it back on.

The fist atm shows the comparison using data from 8-9 PM Saturday night:

  1. there seems to be a factor of 2 calibration diff between the T240 near the BS, and the Guralp seismometers at the end. Which one is right? surpriseWhen was the last time they were cross calibrated?
  2. The low coherence between BS_X and EX_X shows the problem. They should be very coherent (> 0.9) for 0.1-1 Hz.sad

 

Attachment 1: seis_all_191208.pdf
seis_all_191208.pdf
  15084   Sun Dec 8 20:27:11 2019 ranaUpdateComputersViviana upgrade to Ubuntu 16

The IBM laptop at EX was running Ubuntu 14, so I allowed it to start upgrading itself to Ubuntu16 as it desired. After it is done, I will upgrade it to 18.04 LTS. We should have them all run LTS.

  15085   Sun Dec 8 20:48:29 2019 ranaConfigurationComputersMegatron: starts up grade

I noticed recently that Megatron was running Ubuntu 12, so I've started its OS upgrade.

  1. Unlocked the IMC + disabled the autolocker from the LockMC screen + closed the PSL shutter (IMC REFL shutter doesn't seem to do anythin)
  2. Disabled the "FSS" slow servo on the FSS screen
  3. did sudo apt-get update, sudo apt-get upgrade, and then sudo apt-get do-release-upgrade which starts the actual thing
  4. According to the internet, the LTS upgrades will go in series rather than up to 18 in one shot, so its now doing 12 -> 14 (Trusty Tapir)

Megatron and IMC autolocking will be down for awhile, so we should use a different 'script' computer this week.


Mon Dec 9 14:52:58 2019

upgrade to Ubuntu 14 complete; now upgrading to 16

  15095   Wed Dec 11 22:01:24 2019 ranaConfigurationComputersMegatron: starts up grade

Megatron is now running Ubuntu 18.04 LTS.

We should probably be able to load all the LSC software on there by adding the appropriate Debian repos.

I have re-enabled the cron jobs in the crontab.

The MC Autolocker and the PSL NPRO Slow/Temperature control are run using 'initctl', so I'll leave that up to Shruti to run/test.

  15102   Tue Dec 17 20:45:30 2019 ranaUpdatePSLPMC cavity ringdown measurement

idk - I'm recently worried about the 'thermal self locking' issue we discussed. I think you should try to measure the linewidth by scanning (with low input power) and also measure the TF directly by modulating the power via the AOM and taking the ratio of input/output with the PDA55s. I'm curious to see if the ringdown is different for low and high powers

Quote:

I plan to model the PD+AOM as a lowpass filter with an RC time constant of 12us and undo its filtering action on the PMC trans ringdown measurement to get the actual ringdown time.

Is this acceptable?

This is an ole SURF report on thermal self-locking that may be of use (I haven't read it or checked it for errors, but Royal was pretty good analytically, so its worth looking at)

  15141   Wed Jan 22 16:38:01 2020 ranaUpdateComputersrossa revival

wiped and install Debian 10 on rossa today

still to be done: config it as CDS workstation

please don't try to "fix" it in the meantime

  15146   Thu Jan 23 16:37:14 2020 ranaUpdatePSLPMC VGA chip damaged?

doesn't seem so anomolous to me; we're getting ~25 dB of gain range and the ideal range would be 40 dB. My guess is that even thought this is not perfect, the real problem is elsewhere.

  15162   Tue Jan 28 08:26:53 2020 ranaFrogsPEMshaking

https://breakthrough.caltech.edu/magazine/2019-aug/#article-Listening-with-Light

  15193   Thu Feb 6 16:14:44 2020 ranaUpdateGeneraloffice area temperature

I changed the office area thermostate near Steve's desk from 68F to 73F today. Please do not change it.

If anyone from facilities comes to adjust something, please put the details in the elog on the same day so that we can know to undo that change rather than chase down other drifts in the system.

  15217   Wed Feb 19 22:20:22 2020 ranaUpdateALSALS OOL noise with arms locked

Could you please put physical units on the Y-axis and also put labels in the legend which give a physical description of what each trace is?

It would also be good to a separate plot which has the IR locking signal and the green locking signal along with this out of loop noise, all in the same units so that w can see what the ratio is.

  15221   Sun Feb 23 18:15:22 2020 ranaUpdateALSALS OOL noise and PDH

to make the comparisons meaningfully

one needs to correct for the feedback changes

faithfully

  15269   Thu Mar 12 10:43:50 2020 ranaUpdateLoss MeasurementArm transfer function measurement

                               when doing the AM sweeps of cavities

make sure to cross-calibrate the detectors

                       else you'll make of science much frivolities

            much like the U.S. elections electors

  15286   Mon Mar 30 19:02:49 2020 ranaUpdateGeneraldonated cleanroom supplies to Hospitals

Yesterday evening I took nearly all of the masks, gloves, gowns, alcohol wipes, hats, and shoe covers. These were the ones in the cleanroom cabinets at the east end of the Y-arm, as well as the many boxes under the yarm near those cabinets.

This photo album shows the stuff, plus some other random photos I took around the same time (6-7 PM) of the state of parts of the lab.

  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.

  15297   Mon Apr 6 12:26:07 2020 ranaUpdateASCPOP angular FF filters trained and tested

that's pretty great performance. maybe you can also upload some code so that we can do it later too - or maybe in the 40m GIT

I wonder how much noise is getting injected into PRC length at 10-100 Hz due to this. Any change the PRC ERR?

  15302   Mon Apr 13 16:51:49 2020 ranaSummaryDAQNODUS: rsyncd daemon / service set up

I just now modified the /etc/rsyncd.conf file as per Dan Kozak's instructions. The old conf file is still there with the file name appended with today's date.

I then enabled the rsync daemon to run on boot using 'enable'. I'll ask Dan to start the file transfers again and see if this works.

controls@nodus|etc> sudo systemctl start rsyncd.service
controls@nodus|etc> sudo systemctl enable rsyncd.service
Created symlink from /etc/systemd/system/multi-user.target.wants/rsyncd.service to /usr/lib/systemd/system/rsyncd.service.
controls@nodus|etc> sudo systemctl status rsyncd.service
● rsyncd.service - fast remote file copy program daemon
   Loaded: loaded (/usr/lib/systemd/system/rsyncd.service; enabled; vendor preset: disabled)
   Active: active (running) since Mon 2020-04-13 16:49:12 PDT; 1min 28s ago
 Main PID: 4950 (rsync)
   CGroup: /system.slice/rsyncd.service
           └─4950 /usr/bin/rsync --daemon --no-detach

Apr 13 16:49:12 nodus.martian.113.168.192.in-addr.arpa systemd[1]: Started fast remote file copy program daemon.
Apr 13 16:49:12 nodus.martian.113.168.192.in-addr.arpa systemd[1]: Starting fast remote file copy program daemon...

  15306   Sat Apr 18 13:32:31 2020 ranaUpdateCamerasGigE w better NIR sensitivvity

There's this elog from Stephen about better 1064 sensitivity from Basler. We should consider getting one if he finds that its actual SNR is as good as we would expect from the QE improvement.

Might allow for better scatter measurements - not that we need more signal, but it could allow us to use shorter exposure times and reduce blurring due to the wobbly beams.

  15312   Thu Apr 23 10:42:02 2020 ranaUpdatePSLFSS debugging attempts

I had set up the 4395 to do this automatically a few years ago, but it looked at the FSS/IMC instead. When the PCDRIVE goes high there is this excess around ~500 kHz in a broad hump.

But the IMC loop gain changes sometimes with alignment, so I don't know if its a loop instability or if its laser noise. However, I think we have observed PCDRIVE to go up without IMC power dropping so my guess is that it was true laser noise.

This works since the IMC is much more sensitive than PMC. Perhaps one way to diagnose would be to lock IMC at a low UGF without any boosts. Then the UGF would be far away from that noise making frequency. However, the PCDRIVE also wouldn't have much activity.

  15313   Fri Apr 24 00:26:59 2020 ranaSummaryPEML.A. EQ from Tuesday night
Attachment 1: April22-EQ.pdf
April22-EQ.pdf
  15320   Thu May 7 09:43:21 2020 ranaUpdateASCIMC WFS

This is the doc from Keita Kawabe on why the WFS heads should be rotated.

  15325   Tue May 12 17:51:25 2020 ranaSummaryComputer Scripts / Programsupdated LESS syntax highlight on nodus

apt install source-highlight

then modified bashrc to point to /usr/share instead of /usr/bin

  15337   Tue May 19 15:24:06 2020 ranaUpdateBHDBHD mode-matching study

It would be good to have a corner plot with all the distances/ RoCs. Also perhaps a Jacobian like done in this breathtaking and seminal work.

  15345   Fri May 22 10:37:41 2020 ranaUpdateComputer Scripts / ProgramsNDS2 service restarted

was dead again this morning - JZ notified

current restart instructions (after ssh to megatron):

cd /home/nds2mgr/nds2-megatron

sudo su nds2mgr

make -f test_restart

  15346   Mon May 25 10:54:41 2020 ranaUpdateComputer Scripts / ProgramsNDS2 service restarted

so far it has run through the weekend with no problems (except that there are huge log files as usual).

I have started to set up monit to run on megatron to watch this process. In principle this would send us alerts when things break and also give a web interface to watch monit. I'm not sure how to do web port forwarding between megatron and nodus, so for now its just on the terminal. e.g.:

monit>sudo monit status
Monit 5.25.1 uptime: 4m

System 'megatron'
  status                       OK
  monitoring status            Monitored
  monitoring mode              active
  on reboot                    start
  load average                 [0.15] [0.22] [0.25]
  cpu                          0.6%us 1.0%sy 0.2%wa
  memory usage                 1001.4 MB [25.0%]
  swap usage                   107.2 MB [1.9%]
  uptime                       40d 17h 55m
  boot time                    Tue, 14 Apr 2020 17:47:49
  data collected               Mon, 25 May 2020 11:43:03

Process 'nds2'
  status                       OK
  monitoring status            Monitored
  monitoring mode              active
  on reboot                    start
  pid                          25007
  parent pid                   1
  uid                          4666
  effective uid                4666
  gid                          4666
  uptime                       3d 1h 22m
  threads                      53
  children                     0
  cpu                          0.0%
  cpu total                    0.0%
  memory                       19.4% [776.1 MB]
  memory total                 19.4% [776.1 MB]
  security attribute           unconfined
  disk read                    0 B/s [2.3 GB total]
  disk write                   0 B/s [17.9 MB total]
  data collected               Mon, 25 May 2020 11:43:03

 

  15362   Fri May 29 00:34:57 2020 ranaUpdateLSCArm transmission RIN

how bout corner plot with power signals and oplevs? I think that would show not just linear couplings (like your coherence), but also quadratic couplings (chesire cat grin)devil

  15425   Tue Jun 23 17:54:56 2020 ranaConfigurationVACVac maintenance complete

I propose we go for all CAPS for all channel names. The lower case names is just a holdover from Steve/Alan from the 90's. All other systems are all CAPS.

It avoids us having to force them all to UPPER in the scripts and channel lists.

  15435   Sun Jun 28 16:29:58 2020 ranaUpdateSUSMC1 sat-box de-lidded

does the FLIR have an option to export image with a colorbar?

How about just leave the lid open? or more open? I don't know what else can be done in the near term. Maybe swap with the SRM sat box to see if that helps?

  15449   Sun Jul 5 16:14:41 2020 ranaUpdateComputersrossa re-re-revival

maybe we should make a "dd" copy of pianosa in case rossa has issues and someone destroys pianosa by accidentally spilling coffee on it.

So, in summary, rossa is now all set up for use during lock acquisition. However, until this machine has undergone a few months of testing, we should freeze the pianosa config and not mess with it.

  15450   Sun Jul 5 18:25:42 2020 ranaUpdateElectronicsWFS characterization

in the lab, checkin on the WFS

Sun Jul 5 18:25:50 2020

I redid Gautam's measurements to get a baseline before changing the head, and my results are very different: To me it looks like the WFS2 quadrants are all OK.

 

Measurement Details:

  1. The whole AG4395 + breadboard Jenne laser is wheeled over next to the SW side of the AP table.
  2. The output of the 1611 goes into channel R of the 4395
  3. I disconnected all the LEMO cables from the head and then plugged a LEMO-BNC cable into the plugs one at a time. The existing LEMO connectors, which take the signals back to the demode board, were all a little loose, so I adjusted them with some pliers (see video).
  4. The Atten = 0 dB for all AG4395 channels
  5. Source drive = 0 dBm. Checked with a -10 dBm drive that there was no change in the observed TFs, so I guess a 0 dBm drive doesn't make things nonlinear.
  6. When I first turned the setup on, the Yellow 'limit' light was ON on the ILX laser current driver, so maybe the modulation wasn't getting to the laser diode as we wish.
  7. did not change any WFS MEDM settings for these measurements. Not sure if any of those buttons work anyway.

I've left the setup as is in case either me or Gautam want to double check. If we're agreed on this response, I'll remove the notches and disable the RF attenuators.

Sun Jul 5 21:42:45 2020

Attachment 1: WFS_attenOff.pdf
WFS_attenOff.pdf
  15451   Sun Jul 5 18:39:57 2020 ranaUpdateComputersrossa: printer

I did

sudo usermod -a -G lpadmin controlscheeky

and then was able to add Grazia to the list of printers for Rossa by following the instructions on the 40m Wiki. yes


I installed color syntax highlighting on Rossa using the internet (https://superuser.com/questions/71588/how-to-syntax-highlight-via-less). Now if you do 'less genius_code.py', it will be highlighting the python syntax.


when I try 'sitemap' on rossa I get:

medm: error while loading shared libraries: libreadline.so.6: cannot open shared object file: No such file or directory
 

  15454   Mon Jul 6 12:43:02 2020 ranaUpdateComputersrossa: lib symlink

yes, I rebooted yesterday to fix the 'steaking white lines' problem in the video/display

maybe we're supposed to edit something besides resolv.conf since that gets over-written on boot for some linux OS

  15473   Mon Jul 13 11:33:18 2020 ranaUpdateComputersrossa: more developmental work

I too, would prefer py3 for everything, but aren't all the cdsutils / gaurdian things still python2?

Is it possible to just make a python2 conda environment on rossa? I would guess that its simple and won't interfere with the regular operation of that machine.

  15474   Mon Jul 13 11:36:08 2020 ranaUpdateLSCMC2 coils need DC balancing?
  1. if IMC REFL is not increasing, I don't think its a mis-alignment. Usually, REFL is a more sensitive indicator of alignment than TRANS since its usually near zero. Maybe the MC2 TRANS PD is not centered or doesn't have enough lens action.
  2. to reduce the DC load on MC2, you could have a slow releif drive the ETMs and DC and minimize LSC-MCL
  15505   Wed Jul 29 11:57:59 2020 ranaUpdateBHDIn-air BHD - CDS and wiring summary

3. I agree - this whitening will be handy to have for diagnostics.

4. I think in principle, we can ask a company to make the custom cables for us to save us some hand labor. Rich/Chub probably know the right companies to do small numbers of dirty cables.

5. Can't we just a single Noliac PZT in the same way that the OMC does? Or is the lead time too long?

6. Do we need active steering for this in-air test? I'm not even sure how we would get the alignment signal, so maybe that's a good reason to figure this out.

  15509   Fri Aug 7 11:23:47 2020 ranaUpdateBHDMonte Carlo Simulations

that's great. I think we would like to figure out how to present this so that its clear what the distribution of TFs is. Maybe we can plot the most likely curve as well as a shaded region indicating the 5% and 95% values?

Quote:

I've pushed an MCMC simulation to the A+ BHD repo (filename MCMC_TFs.ipynb). The idea is to show how random offsets around ideal IFO change the noise couplings of different DOFs to readout.

and then we add the loops

  15533   Tue Aug 18 13:55:23 2020 ranaUpdateALSWhitening and ALS noise

No, there should be no unscheduled visits from any inspector, marshal, tech, or vendor. They all have to be escorted or they don't get in. If they have a problem with that, please give them my cell #.

 

For the ALS, in addition to the beat note spectrum, I think we need to know the loop gain use to feedback to the ETM to determine the true cavity length fluctuation. w/o ALS, the noise would be only due to the seismic noise, OSEM damping noise, and the IR-PDH residual. Those are all suppressed by the ALS loop, but then the ALS loop puts its sensing noise onto the cavity. So, if I'm thinking about this right, the ALS beat noise > 200 Hz doesn't matter so much to the CARM RMS. So the whitening seems to be doing good in the right spot, but we would like to have another boost in the green PDH to up the gain below ~300 Hz?

  15546   Sat Aug 29 18:52:42 2020 ranaUpdateIOOIMC gain change

I lowered the (FAST) PZT gain on the IMC/FSS servo today.

I noticed that the MC locks looked unstable a lot of the day, and during lock the PCDRIVE channel is above 1 Vrms (which means the loop is oscillating, ttypically at the PZT/EOM crossover frequency).

I changed the default setting from 22 to 20 19 dB in the PSL Settings screen so the mcup script will use this for now. Feel free to revert if this turns out to be a Fluke (which you would think is a terrible name for a company, but...)

  15547   Sat Aug 29 20:07:48 2020 ranaUpdateElectronicsWFS characterization

I set up to do the WFS head modifications today, but I was shot down in flames due to a missing AC/DC adapter.

The Prologix GPIB-ethernet dongle needs +8-13 V to run. Some riff raff has removed the adapter and I was thunderstruck to see that it had not been returned.

I did the usual hunt around the lab looking for something with the right specs and connector. I found one that could do +9V and had the right connector, but it didn't light up the adapter so I put it back in black SP table.

I'll order a couple of these (5 ordered for delivery on Wednesday) in case there's a hot demand for the jack / plug combo that this one has. The setup is in the walkway, but I returned the AS table to the usual state and made sure the IMC is locking well.

  15550   Sun Aug 30 11:29:33 2020 ranaUpdateGeneralpower blink?

My power at home winked out for a second this morning, but it looks like either nothing happened in the 40m lab or else it rode it out.

MC is locked - lost lock around 11:25 AM and then relocked.

  15566   Wed Sep 9 20:52:45 2020 ranaSummaryIOOwandering line in IMC

since the summary pages are working again, I was clicking through and noticed that there's a wandering peak in the whitened IMC spectrogram that goes from 10-30 Hz over the course of a day.

https://nodus.ligo.caltech.edu:30889/detcharsummary/day/20200909/ioo/

anyone know what this is ?

  15574   Tue Sep 15 19:17:30 2020 ranaUpdateIOOMC F spectrum

that's a very curious disconnection

the "Pentek" whitening board that carries the MC channels has jumpers to enable either 1 or 2 stages of 15:150 whitening. Looks lik MC_F has 2 and MC_L has 1.

I guess the MC_F signal is so low because of the high gain on the FSS board.  We could lower the FSS common gain and increase the IMC board's VCO gain to make up for this. Maybe 6 dB would be enough. IF that is risky, we could also up the analog gain on the whitening board.

  15581   Sat Sep 19 11:27:04 2020 ranaUpdateGeneralM4.5 EQ in LA

the seismometers obviously saturated during the EQ, but the accelerometers captured some of it. It looks like there's different saturation levels on different sensors.

Also, it seems the mounting of the MC2 accelerometers is not so good. There's some ~10-20 Hz resonance its mount that's showing up. Either its the MC2 chamber legs or the accelerometers are clamped poorly to the MC2 baseplate.

Sun Sep 20 00:02:36 2020 edit: fixed indexing error in plots

* also assuming that the sensors are correctly calibrated in the front end to 1 count = 1 um/s^2 (this is what's used in the summ pages)

Attachment 1: Sep18-EQ.pdf
Sep18-EQ.pdf
  15583   Sat Sep 19 18:08:34 2020 ranaUpdateGeneralM4.5 EQ in LA

the EQ was ~14 km south of Caltech and 17 km deep

Quote:

the seismometers obviously saturated during the EQ, but the accelerometers captured some of it. It looks like there's different saturation levels on different sensors.

Also, it seems the mounting of the MC2 accelerometers is not so good. There's some ~10-20 Hz resonance its mount that's showing up. Either its the MC2 chamber legs or the accelerometers are clamped poorly to the MC2 baseplate.

I'm amazed at how much higher the noise is on the MC2 accelerometer. Is that really how much amplification of the ground motion we're getting? If so, its as if the MC has no vibration isolation from the ground in that band. We should put one set on the ground and make the more direct comparison of the spectra. Also, perhaps do some seismic FF using this sensor - I'm not sure how successful we've been in this band.

Attaching the coherence plot from ldvw.ligo.caltech.edu (apparently it has access to the 40m data, so we can use that as an alternative to dtt or python for remote analysis):

Coherence (GWpy) result, image #: 288304

It would be interesting to see if we can use the ML based FF technology from this summer's SURF project by Nadia to increase the coherence by including some slow IMC alignment channels.

  15589   Sun Sep 20 23:12:13 2020 ranaSummaryALSALS noise budget update

I think the digital loop in the ALS budget is too optimistic. You have to include all the digital delays and anti-aliasing filters to get the real response.

aslo, I recommend grabbing some of the actual spectra from the in-lock times with nds and using the calibrated spectra as inputs to this mode. Although we don't have good models of the stack, you can sort of infer it by using the calibrated seismometer data and the calibrated MC_F or MC_L channels (for IMC) or XARM/YARM signals for those.

  15594   Tue Sep 22 12:14:42 2020 ranaSummaryALSALS noise budget update

This ALS loop is not stable. Its one of those traps that comes from using only the Bode plot to estimate the loop stability. You have to also look at the time domain response - you can look at my feedback lecture for the SURF students for some functions.

  15605   Wed Sep 30 19:45:56 2020 ranaUpdateGeneralHEPA blower startup capacitor replacement

it would be a good idea for us to have an auto-reminder to have us check the flow of all the HEPAs in the lab and elog it once a year so that we can replace filters and pre-filters appropriately.

ELOG V3.1.3-