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ID Date Author Type Category Subjectup
  7141   Fri Aug 10 11:00:52 2012 SashaUpdateSimulationsMessing with ETMX

I've been trying to get the simPlant model to work, and my main method of testing is switching between the real ETMX and the simulated ETMX and comparing the resulting power spectrum (the closer the two are, the more our simulation works). While the simPlant is on, ETMX is NOT BEING DAMPED. I started this ~Wednesday, and the testing will continue today, then hopefully we'll get a similiar simPlant up for ITMX (at which point, testing will continue for both ITMX and ETMX).

TL;DR: ETMX is not being continuously damped, XARM will likely be exhibiting some wonky behavior next week.

  15176   Thu Jan 30 12:52:10 2020 JonUpdateBHDMetal OMCs procured

Last night Yehonathan and I located the two steel PMCs in the QIL, with help from Anchal. They are currently sitting on my desk in Bridge, inside a box that also contains optics and other OMC parts. I will bring them over to the 40m the next time I come.

  15182   Fri Jan 31 16:57:09 2020 gautamUpdateGeneralMetal PMC parts

Jon brought over a box of parts for constructing the metal PMCs. I have stored it along the Y-arm, on top of the green optics cabinet.

I didn't do an exhaustive inventory check, but the following are the rough contents of the box:

  • 41 deg AoI flat mirrors, R=99% @ 1064nm --- 11 pcs
  • 6.8 deg AoI curved mirrors --- 5 pcs
  • PZTs --- 3pcs
  • Metal PMC body --- 2 pcs
  • "Baked PZT endcaps" --- 3 pcs
  • Ball bearings, clamps, misc hardware

I didn't inspect the optics but since we have so many, I am hoping we can find 3 good quality ones for one cavity at least. We should check that the geometry is suitable for our RF sideband frequencies.  

  15198   Fri Feb 7 12:58:25 2020 YehonathanUpdateGeneralMetal PMC parts

I took the metal PMC box and examined its content and find the following items:

Name Quantity Picture (Attachment #)
Metal PMC body (PMC1) 1 1-3
Metal PMC body with two mounted 41 deg mirrors (PMC2) 1 4-6
"Baked PZT Caps" 3 7
PZT Caps 2 8
Flat mirror mounts 2 9
Bar clamps 4 10
Clamp studs 8 10
PZTs 4 11
ORings INF 12
Ball bearings INF 13
6.8 deg AoI curved mirrors (r=-1000mm) 6 14
41 deg AoI flat mirrors, R=99% @ 1064nm (1 Damaged) 11 15

There seem to be enough parts to build 2 PMCs + spares.

I find several problems in the metal PMCs:

PMC1 has a broken screw in one of its flat mirror mounts (Attachment 16). We need to get it out in the machine shop.

PMC2 one of the flat mirrors has a scratch on the AR coating and its ORing is failing (Attachment 17). Mirror and ORing need to be replaced.

I measure the physical dimensions of the PMC with the help of https://dcc.ligo.org/LIGO-E1400332. The roundtrip is found to be 24cm which gives an FSR of 1.25GHz.

I use Evan Hall's Python script for calculating the mode spectrum as a function of the cavity length of the metal PMC and overlay the RF sidebands (Green dashed lines) on it (Attachment 18) to check for any HOM coincidence. The width of the lines is the mode splitting due to the cavity astigmatism.

It seems like the only issue might come from a 10th order modes (green ribbon) which are hopefully small enough in reality.

Attachment 1: PMC1Side.jpg
PMC1Side.jpg
Attachment 2: PMC1Front.jpg
PMC1Front.jpg
Attachment 3: PMC1Back.jpg
PMC1Back.jpg
Attachment 4: PMC2Side.jpg
PMC2Side.jpg
Attachment 5: PMC2Back.jpg
PMC2Back.jpg
Attachment 6: PMC2Front.jpg
PMC2Front.jpg
Attachment 7: 20200207_123118.jpg
20200207_123118.jpg
Attachment 8: 20200207_123055.jpg
20200207_123055.jpg
Attachment 9: 20200207_122448.jpg
20200207_122448.jpg
Attachment 10: 20200207_122400.jpg
20200207_122400.jpg
Attachment 11: 20200207_122040.jpg
20200207_122040.jpg
Attachment 12: 20200207_122227.jpg
20200207_122227.jpg
Attachment 13: 20200207_122149.jpg
20200207_122149.jpg
Attachment 14: 20200207_123328.jpg
20200207_123328.jpg
Attachment 15: 20200207_123405_HDR.jpg
20200207_123405_HDR.jpg
Attachment 16: PMC1Screw.jpg
PMC1Screw.jpg
Attachment 17: PMC2BadMirror.jpg
PMC2BadMirror.jpg
Attachment 18: homVersusLength.pdf
homVersusLength.pdf
  12356   Fri Jul 29 19:37:43 2016 PrafulUpdateElectronicsMic Amplifier

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

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

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

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

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

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

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

ampTest_03-08-2016_180448.pdf

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

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

Attachment 2: ampTest_03-08-2016_180448.pdf
ampTest_03-08-2016_180448.pdf
Attachment 3: ampTest_03-08-2016_180448.txt
# SR785 Measurement - Timestamp: Aug 03 2016 - 18:04:48
#---------- Measurement Setup ------------
# Start frequency (Hz) = 1.000000
# Stop frequency (Hz) = 102400.000000
# Number of frequency points = 800
# Excitation amplitude (mV) = 50.000000
# Settling cycles = 1
# Integration cycles = 5
#---------- Measurement Parameters ----------
# Measurement Group:  "Swept Sine" "Swept Sine"
... 820 more lines ...
Attachment 4: simple_amp.png
simple_amp.png
  12380   Fri Aug 5 16:25:08 2016 PrafulUpdateElectronicsMic Amplifier

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

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

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

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

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

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

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


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

  12396   Wed Aug 10 19:37:08 2016 gautamUpdateElectronicsMic Amplifier

In order to help Praful do his huddle test, I have temporarily arranged for the outputs of the 3 channels he wants to monitor to be acquired as DQ channels at 2048 Hz by editing the C1PEM model. No prior DQ channels were set up for the microphones. Data collected overnight should be sufficient for Praful's analysis, so we can remove these DQ channels from C1PEM before committing the updated model to the svn. There is in fact a filter that is enabled for these microphone channels that claims to convert the amplified microphone output to Pascals, but it is just a gain of 0.0005. 

In the long term, once we install microphones around the IFO, we can update C1PEM to reflect the naming conventions for the microphones as is appropriate.

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

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

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

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

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

mic1_wiener.pdf

mic2_wiener.pdf

mic3_wiener.pdf

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

Mic 1: 0.00036 V

Mic 2: 0.00023 V

Mic 3: 0.00028 V

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

timeseries_elog.pdf

 

 

Attachment 4: mic1_wiener.pdf
mic1_wiener.pdf
Attachment 5: mic2_wiener.pdf
mic2_wiener.pdf
Attachment 6: mic3_wiener.pdf
mic3_wiener.pdf
Attachment 7: timeseries_elog.pdf
timeseries_elog.pdf
  12406   Fri Aug 12 21:26:28 2016 ranaUpdatePEMMic Self Noise

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

  12408   Mon Aug 15 12:23:56 2016 PrafulUpdatePEMMic Self Noise

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

This seems to be working well so far:

freq1.pdf

freq2.pdf

freq3.pdf

Here's all the plots on one figure:

frequency_dependent.pdf

Let me know if this looks believable.

Quote:

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

 

Attachment 1: freq1.png
freq1.png
Attachment 2: freq1.pdf
freq1.pdf
Attachment 4: freq2.pdf
freq2.pdf
Attachment 6: freq3.pdf
freq3.pdf
Attachment 8: frequency_dependent.pdf
frequency_dependent.pdf
  7145   Fri Aug 10 16:39:44 2012 EricSummaryLockingMichelson Locking

I'm working on locking the Michelson now in order to put an excitation on one of the input test masses and measure the resulting error signal at the anti-symmetric port. I aligned the beams from ITMX and ITMY by looking at the AS camera with the video screens, but the fringes were not destructively interfering. Jenne advised that I look at the gain on the MICH servo filter modules in the LSC screen. We flipped the sign on the gain (it was 0.120 and it is now -0.120) and the fringes destructively interfered as desired after this change.

For purposes of documentation, I locked the YARM earlier in the morning before moving on to the Michelson. The purpose of this was to put another excitation on C1:SUS-ETMY_LSC_EXC and then measure the error signal on C1:LSC-POY11_I_ERR.

  7149   Fri Aug 10 19:49:11 2012 EricSummaryLockingMichelson Locking Procedure and Measurements

Today I worked on locking the Michelson. Here's what I did:

 

  1. Open Data Viewer and Restore Settings /users/Templates/JenneLockingDataviewer/MICH.xml. This opens the C1:LSC-ASDC_OUT and C1:LSC-AS55_Q_ERR plots.

  2. Check the LSC screen to verify that the path between the Servo Filter Modules and the SUS Ctrls are outlined in green. If not turn on the OUT button within the Filter Servo Modules, enable LSC mode, and turn on the SUS Ctrls for the BS.

  3. Misalign all optics other than BS and one of ITMX and ITMY. The ITMY was already well-aligned from my work on locking the YARM, so I actually chose to misalign ITMY at first.

  4. Restore BS and ITMX. Use the AS camera on the video screen as your guide when aligning ITMX.

  5. Adjust pitch and yaw of ITMX until a bright, circular spot appears near the middle of the AS camera.

  6. Now restore ITMY and adjust pitch and yaw until a second circular spot appears on the AS camera.

  7. Adjust both ITMX and ITMY until both bright spots occupy the same location. If the spots remain bright when they are in the same location you are locking onto a bright fringe actually, and need to flip the sign of the gain on the MICH servo filter modules. I had to do this today in fact, as discussed in ELOG 7145.

  8. If the sign is correct, the two beams should interfere destructively and the formerly bright spots will form a comparatively dark spot. The shape of the spot will likely be two bright lobes separated by a dark middle.

  9. C1:LSC-ASDC_OUT should be a roughly flat signal, and the goal now is to minimize the magnitude of this signal. The smaller this signal, the darker the AS camera should look. Decent target values for C1:LSC-ASDC_OUT are around 0.10 to 0.05.

 

Once I did this, I made measurements by exciting C1:SUS-ITMY_LSC_EXC and measuring with C1:LSC-AS55_Q_ERR. I ran a logarithmic swept sine response from 1 to 1000 Hz again, with an envelope amplitude dependence. Again I looked at the measured transfer function and coherence. I was able to get good coherence, but it was somewhat erratic in that it dipped low at high frequency multiple times.

  4527   Fri Apr 15 02:17:18 2011 kiwamuUpdateLSCMichelson locked

[Koji / Kiwamu]

The Michelson was locked with the new LSC realtime code.

 

 

(what we did)

 --  Fine alignment of the Michelson, including PZTs, BS and ITMY.

  Since the X arm has been nicely aligned we intentionally avoided touching ITMX. The IR beam now is hitting the center of both end mirrors.

  At the end we lost X arm's resonance for IR. This probably means the PZTs need more careful alignments.

 

-- Signal acquisition

 We replaced the RFPD (AS55) that Aidan and Jamie nicely installed by POY11 because we haven't yet  installed a 55MHz RF source.

The maximum DC voltage from the PD went to about 50 mV after aligning steering mirrors on the AP table.

The RF signal from the PD is transferred by a heliax cable which has been labeled 'REFL33'.

Then the RF signal is demodulated at a demodulation board 'AS11', which is one of the demodulation boards that Suresh recently modified.

Although we haven't fully characterized the demod board the I and Q signal looked healthy.

Finally the demod signals go to ADC_0_3 and ADC_0_4 which are the third and fourth channel.

They finally show up in REFL33 path in the digital world.

 

-- Control

 With the new LSC code we fedback the signal to BS. We put anti-whitening filters in the I and Q input filter banks.

We found that dataviewer didn't show correct channels, for example C1LSC_NREFL33I showed just ADC noise and C1LSC_NREFL33Q showed NREFL_33I.

Due to this fact we gave up adjusting the digital phase rotation and decided to use only the I-phase signal.

Applying a 1000:10 filter gave us a moderate lock of the Michelson. The gain was -100 in C1LSC_MICH_GAIN and this gave us the UGF of about 300 Hz.

 Note that during the locking both ETMs were intentionally misaligned in order not to have Fabry-Perot fringes.

  9603   Wed Feb 5 18:36:56 2014 ranaFrogselogMicroSoft BingBot is attacking us

 The ELOG was frozen, with this in the .log file:   

GET /40m/?id=1279&select=1&rsort=Type HTTP/1.1

Cache-Control: no-cache

Connection: Keep-Alive

Pragma: no-cache

Accept: */*

Accept-Encoding: gzip, deflate

From: bingbot(at)microsoft.com

Host: nodus.ligo.caltech.edu

User-Agent: Mozilla/5.0 (compatible; bingbot/2.0; +http://www.bing.com/bingbot.htm)

  (hopefully there's a way to hide from the Bing Bot like we did from the Google bot)

 

  10309   Thu Jul 31 18:54:03 2014 ChrisFrogselogMicroSoft BingBot is attacking us

Quote:

 The ELOG was frozen, with this in the .log file:   

GET /40m/?id=1279&select=1&rsort=Type HTTP/1.1

Cache-Control: no-cache

Connection: Keep-Alive

Pragma: no-cache

Accept: */*

Accept-Encoding: gzip, deflate

From: bingbot(at)microsoft.com

Host: nodus.ligo.caltech.edu

User-Agent: Mozilla/5.0 (compatible; bingbot/2.0; +http://www.bing.com/bingbot.htm)

  (hopefully there's a way to hide from the Bing Bot like we did from the Google bot)

 

Yesterday elog was excruciatingly slow, and bingbot was the culprit. It was slurping down elog entries and attachments so fast that it brought nodus to its knees. So I created a robots.txt file disallowing all bots, and placed it in the elog's scripts directory (which gets served at the top level). Today the log feels a little snappier -- there's now much less bot traffic to compete with when using it.

We might be able to let selected bots back in with a crawl rate limit, if anyone misses searching the elog on bing.

  10311   Thu Jul 31 21:21:49 2014 KojiFrogselogMicroSoft BingBot is attacking us

Oh, this is cool! Thanks!
I could not figure out how to place robot.txt as it was not so obvious how elogd handles the files in the "logfile" directory.

  12436   Wed Aug 24 14:11:09 2016 PrafulUpdateElectronicsMicrophone Testing

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

white_v_ambient.pdf

Attachment 1: white_v_ambient.png
white_v_ambient.png
Attachment 2: white_v_ambient.pdf
white_v_ambient.pdf
Attachment 3: white_v_ambient.pdf
white_v_ambient.pdf
  7633   Fri Oct 26 18:25:02 2012 AyakaUpdateAdaptive FilteringMicrophone noise again

[Raji, Ayaka]

Thanks to Den, power supplies for microphone circuit are changed.
So I measured the microphone noise again by the same way as I did last time.

mic_noise.png
  solid lines: acoustic noise
 dashed lines: un-coherent noise
black line: circuit noise (microphone unconnected)

The circuit noise improves so much, but many line noises appeared.
Where do these lines (40, 80, 200 Hz...) come from?
These does not change if we changed the microphones...

Anyway, I have to change the circuit (because of the low-pass filter). I can check if the circuit I will remake will give some effects on these lines.

  7634   Fri Oct 26 19:06:14 2012 DenUpdateAdaptive FilteringMicrophone noise again

Quote:

The circuit noise improves so much, but many line noises appeared.
Where do these lines (40, 80, 200 Hz...) come from?
These does not change if we changed the microphones...

Anyway, I have to change the circuit (because of the low-pass filter). I can check if the circuit I will remake will give some effects on these lines.

I do not think that 1U rack power supply influenced on the preamp noise level as there is a 12 V regulator inside. Lines that you see might be just acoustic noise produced by cpu fans. Usually, they rotate at ~2500-3000 rpm => frequency is ~40-50 Hz + harmonics. Microphones should be in an isolation box to minimize noise coming from the rack. This test was already done before and described here

I think we need to build a new box for many channels (32, for example, to match adc). The question is how many microphones do we need to locate around one stack to subtract acoustic noise. Once we know this number, we group microphones, use 1 cable with many twisted pairs for a group and suspend them in an organized way.

  7636   Mon Oct 29 08:41:22 2012 AyakaUpdateAdaptive FilteringMicrophone noise again

Quote:

Quote:

The circuit noise improves so much, but many line noises appeared.
Where do these lines (40, 80, 200 Hz...) come from?
These does not change if we changed the microphones...

Anyway, I have to change the circuit (because of the low-pass filter). I can check if the circuit I will remake will give some effects on these lines.

I do not think that 1U rack power supply influenced on the preamp noise level as there is a 12 V regulator inside. Lines that you see might be just acoustic noise produced by cpu fans. Usually, they rotate at ~2500-3000 rpm => frequency is ~40-50 Hz + harmonics. Microphones should be in an isolation box to minimize noise coming from the rack. This test was already done before and described here

I think we need to build a new box for many channels (32, for example, to match adc). The question is how many microphones do we need to locate around one stack to subtract acoustic noise. Once we know this number, we group microphones, use 1 cable with many twisted pairs for a group and suspend them in an organized way.

 I do not think they are acoustic sounds. If so, there should be coherence between three microphones because I placed three at the same place, tied together. However, there are no coherence at lines between them.

  448   Fri Apr 25 13:20:04 2008 AndreyUpdatePEMMicrophone test
In response to Rana's request, I tested the microphone (if it is alive or not) by clapping my hands and speaking aloud nearby.

The microphone is alive, see the attached "Full Data" for 5 minutes from Dataviewer.
Attachment 1: Microphone.png
Microphone.png
  4853   Wed Jun 22 12:24:44 2011 NicoleSummarySUSMidweek 2 Work Summary

I have made my transfer function model and posted it to the suspension wiki. Here is the link to my model!

Bode Plot Model

Please let me know if there need to be any adjustments, but I have posted the bode plots, a model image, and an explanation of why I think it's right! ^ ___^ V

I am currently working on the photo sensor circuit for the displacement detector. So far, I have gotten the infared LED to light up! ^ ___^ V

I am now trying to get a plot of forward voltage versus current for the LED. HOPEFULLY it will match the curve provided in the LED datasheet.

I'm using the bread board circuit box and when I'm not working at the bench, I have signs posted. PLEASE DO NOT REMOVE THE CONNECTIONS! It is

fine to move the bread board circuit box, but please do not disturb the connections > ____<

Here is a photo of the workspace

P6220200.JPG

  1808   Wed Jul 29 14:56:44 2009 JenneUpdatePEMMiniEarthquakes due to construction

The construction people next door seem to be getting pretty excited about pounding things lately.  At my desk the floor was shaking like a mini-earthquake, and all of the accelerometers were pretty much railed. Clara has the Guralp box out right now, so the Guralp is unplugged, but the Ranger didn't seem to be railed.

This either (a) is part of the reason the MC is being wonky lately, or (b) has nothing whatsoever to do with it.  The MC watchdogs haven't been tripping all the time, so maybe this isn't a primary cause of the wonky-ness.

In looking at a many-days/months trend to see how far back this has been going, it looks like the accelerometers are hitting their rails pretty much all day every day.  This may be significantly hindering Clara's Wiener filtering work.  I think the gain on the accelerometer's controler panel is already set to 1, but if it's set to 10, we may want to reduce that.  Alternatively, we may want to put in attenuators just as the signal is entering the PEM ADCU, to help reduce the amount of rail-hitting that's going on. I don't remember this from a couple of months ago, so this may be a problem that will go away once the construction / landscaping is done next door.

  9010   Tue Aug 13 22:21:12 2013 KojiSummaryGeneralMinicircuit Filter TFs (AG4395A test)

As a part of the network analyzer test in the previous entry, the transfer functions of Mini-Circuits filters we have at the 40m were measured.

<<List of the filters>>

- LPF (SMA): SLP1.9, SLP5, SLP21.4, SLP30, SLP50, SLP100, SLP150, SLP750
- LPF (BNC): BLP1.9, BLP2_5, BLP5, BLP30
- BPF (SMA): SBP10.7, SBP21.4, SBP70
- HPF (SMA): SHP25, SHP100, SHP150, SHP200, SHP500

 

Attachment 1: Minicircuit_LPF.pdf
Minicircuit_LPF.pdf
Attachment 2: Minicircuit_BPF.pdf
Minicircuit_BPF.pdf
Attachment 3: Minicircuit_HPF.pdf
Minicircuit_HPF.pdf
Attachment 4: 130813.zip
  8161   Mon Feb 25 20:49:07 2013 BrettUpdateSUSMinor Mod made to SUS_GLOBAL block

 I made a minor modification to install some output filters in the new global damping GLOBAL box in c1sus.mdl. These will be needed for tuning the suspension drives to compensate for mismatches in the pendulums.

I recompiled and installed the model, but did not start it. Basically same as Jamie left it in 8159. Interestingly, I did not see the new POSOUT that was put in before the SUSPOS DOF filter. I made sure to reopen the .mdl file fresh before making more mods, but for some reason I do not see that update...

  11385   Tue Jun 30 20:26:24 2015 Eve UpdateGeneralMinor Summary Page Changes

I made several small, nit-picky changes to the summary pages.

 

Motivation:

I'm still working on getting used to editing the summary pages. I also wanted to change some of the easy-to-alter cosmetics of the pages.

 

What I did:

I changed axis ranges, axis labels, and typos throughout the summary pages. Read below for an excrutiating list of the minor details of my alterations, if you wish:

  • Changed axes on LSC control signals plots on the Summary tab (but will probably change these back to their original state)
  • Moved an OpLev plot from the Sandbox tab to "Eve" tab
  • Increased the y axis range on IOO MC2 Trans QPD and IMC REFLY RFPD DC plots (which may change when I better incorporate triggers into these plots)
  • Fixed title on IOO Whitened Spectrogram and Rayleigh Spectrogram
  • Fixed degree sign on Weather: Temperature and PSL Table Temperature
  • Fixed percent sign on Weather: Humidity
  •  

Results:

So far, everything looks good. I'll continue to make more changes later this week and hope to soon get on to more substatial changes.

  1984   Fri Sep 11 17:07:45 2009 JenneUpdateAdaptive FilteringMinor changes to ASS_TOP_PEM screen.

There was some uncertainty as to which channels were being input into the Adaptive Filtering screen, so I checked it out to confirm.  As expected, the rows on the ASS_TOP_PEM screen directly correspond to the BNC inputs on the PEM_ADCU board in the 1Y6 (I think it's 6...) rack.  So C1:ASS-TOP_PEM_1_INMON corresponds to the first BNC (#1) on the ADCU, etc. 

After checking this out, I put text tags next to all the inputs on the ASS_TOP_PEM screen for all of the seismometers (which had not been there previously).  Now it's nice and easy to select which witness channels you want to use for the adaptation.

  2628   Mon Feb 22 13:08:27 2010 josephbUpdateComputersMinor tweaks to c1omc

While working on c1omc, I created a .cshrc file in the controls home directory, and had it source the cshrc.40m file so that useful shortcuts like "target" and "c" work, among other things.  I also fixed the resolv.conf file so that it correctly uses linux1 as its name server (speeding up ssh login times).

  12776   Tue Jan 31 15:08:13 2017 ericqMetaphysicsCDSMinute Trend Koan

A novice was learning at the feet of Master Daqd. At the end of the lesson he looked through his notes and said, “Master, I have a few questions. May I ask them?”

Master Daqd nodded.

"Do we record minute trends of our data?"

"Yes, we record raw minute trends in /frames/trend/minute_raw"

"I see. Do we back up minute trends?"

"Yes, we back up all frames present in /frames/trend/minute"

"Wait, this means we are not recording our current trends! What is the reason for the existence of seperate minute and minute_raw trends?

“The knowledge you seek can be answered only by the gods.”

"Can we resume recording the minute trends?"

Master Daqd nodded, turned, and threw himself off the railing, falling to his death on the rocks below.

Upon seeing this, the novice was enlightened. He proceeded to investigate how to convert raw minute trends to minute trends so that historical records could be preserved, and precisely when Master Daqd started throwing himself off the mountain when asked to record minute trends.

  12777   Tue Jan 31 17:28:36 2017 ranaSummaryCDSMinute Trend Koan

Someone installed "Debian" on allegra. Why? Dataviewer doesn't work on there. Is there some advantage to making this thing have a different OS than the others? Any objections to going back to Ubuntu12?

  12779   Tue Jan 31 20:25:26 2017 ericqSummaryCDSMinute Trend Koan
Quote:

Someone installed "Debian" on allegra. Why? Dataviewer doesn't work on there. Is there some advantage to making this thing have a different OS than the others? Any objections to going back to Ubuntu12?

My elog negligence punchcard is getting pretty full... It's pretty much for the same reason as using Debian for optimus; much of the workstation software is getting packaged for Debian, which could offload our need for setting things up in a custom 40m way. Hacking the debian-focused software.ligo.org repos into Ubuntu has caused me headaches in the past. Allegra wasn't being used often, so I figured it was a good test bed for trying things out.

The dataviewer issue was dataviewer's inability to pull the `fb` out of `fb:8088` in the NDSSERVER env variable. I made a quick fix for it in the dataviewer launching script, but there is probably a better way to do it.

  12791   Thu Feb 2 18:28:29 2017 ranaSummaryCDSMinute Trend Koan

and the song remains the same...

the version of SVN on these workstations is ahead of the one on the other workstations so now we can't do 'svn up' on any of the Ubuntu12 machines. One allegra and optimus I get this error:

controls@allegra|GWsummaries> svn up
Updating '.':
svn: E180001: Unable to connect to a repository at URL 'file:///cvs/cds/caltech/svn/trunk/GWsummaries'
svn: E180001: Unable to open an ra_local session to URL
svn: E180001: Unable to open repository 'file:///cvs/cds/caltech/svn/trunk/GWsummaries'

Quote:
Quote:

Someone installed "Debian" on allegra. Why? Dataviewer doesn't work on there. Is there some advantage to making this thing have a different OS than the others? Any objections to going back to Ubuntu12?

My elog negligence punchcard is getting pretty full... It's pretty much for the same reason as using Debian for optimus; much of the workstation software is getting packaged for Debian, which could offload our need for setting things up in a custom 40m way. Hacking the debian-focused software.ligo.org repos into Ubuntu has caused me headaches in the past. Allegra wasn't being used often, so I figured it was a good test bed for trying things out.

The dataviewer issue was dataviewer's inability to pull the `fb` out of `fb:8088` in the NDSSERVER env variable. I made a quick fix for it in the dataviewer launching script, but there is probably a better way to do it.

I'm not sure if its possible to downgrade our chans repo back to the old one, but I highly recommend that no one do 'svn upgrade' in any of our repos until we remove all of the Debian installs in the 40m lab or hire a full-time sysadmin.

  4410   Fri Mar 18 11:29:36 2011 josephbUpdateCDSMinute trend issues

[Joe, Alex]

Steve pointed out to me today he couldn't get trends for his PEM slow channels like C1:PEM-count_full. 

I experimented a bit and found for long time requests (over 20 days), it would produce minute trends up to the current time, but only if they started far enough back.  So the data was being written, but something was causing a problem for dataviewer/NDS to find it.

On further investigation it looks to be some incorrect time stamps at several points in the last few months are causing the problems.  Basically when Alex and I made mistakes in the GPS time stamp settings for the frame builder (daqd) code, the wrong time got written for hours to the raw minute trend data files.

So Alex is going to be running a script to go through the roughly 180 gigabytes of affected trend data to write new files with the correct time stamps.  Once it done, we'll move the files over.  We'll probably lose a few hours worth of recent trend data, depending on how quickly the scripts run, but after which minute trends should work as they are supposed to.

  2887   Thu May 6 17:47:01 2010 Alberto, kiwamu, Jc The 3rd (aka The Drigg)OmnistructureTMIMinutes from the Lab Organization Commitee meeting

Today we met and we finally come up with a lot of cool, clever, brilliant, outstanding ideas to organize the lab.

You can find them on the Wiki page created for the occasion.

http://lhocds.ligo-wa.caltech.edu:8000/40m/40m_Internals/Lab_Organization

Enjoy!

  2888   Thu May 6 17:54:44 2010 Zach Korth -- Committee Oversight (Fun Division)OmnistructureTMIMinutes from the Lab Organization Commitee meeting

Where are we going to put the tiki bar? The ice cream machine? I am disappointed in the details that appear to have been glossed over..

Quote:

Today we met and we finally come up with a lot of cool, clever, brilliant, outstanding ideas to organize the lab.

You can find them on the Wiki page created for the occasion.

http://lhocds.ligo-wa.caltech.edu:8000/40m/40m_Internals/Lab_Organization

Enjoy!

 

  15070   Wed Dec 4 08:54:07 2019 YehonathanUpdateIMCMirror analog shaking

{Yehonathan, Gavin}

Yesterday we tried to shake ITMX with a function generator in order to observe the 28.8kHz drum mode.

We laid a long BNC cable that runs from the YARM to the XARM. This cable either needs to be collected back to the BNC big plastic cable box under the IMC or be labeled so that it could be found easily in the future.

First, we tried to shake it at a lower frequency (100's of Hz) where the shaking should be easily observed in the POSX channel. We try driving the POS channel on the ITMX servo but nothing happens. Most likely it is disconnected.

While setting up for shaking the individual OSEM channels 4 CDSs crashed (c1lsc, c1ass, c1oaf, c1cal).

 

  8190   Wed Feb 27 19:27:29 2013 AnnalisaHowToCOMSOL TipsMirror support Eigenfrequency

 I studied the eigenfrequencies of a mirror support using COMSOL.

 

Attachment 1: IronSupport.png
IronSupport.png
Attachment 2: IronSupportEigenfreq.png
IronSupportEigenfreq.png
  7379   Thu Sep 13 17:19:45 2012 JenneUpdateSUSMirrors being installed on active TTs

I have given Den 4 G&H R>99.99% mirrors to be installed on the 4 active tip tilts.  He's in there working on things (incl. installing and balancing the pitch of the mirrors) right now.  He'll elog his work later.

  7384   Fri Sep 14 01:05:36 2012 DenUpdateSUSMirrors being installed on active TTs

Quote:

I have given Den 4 G&H R>99.99% mirrors to be installed on the 4 active tip tilts. 

 I've installed the mirrors on 4 tip-tilts. I was able to align 3 of them in pitch, the last one has a screw with damaged thread, I'll continue with it tomorrow.

Alignment accuracy in pitch is ~0.1 mrad. Mirrors oscillate a lot probably due to air flow coming from the side wall.

  2987   Wed May 26 00:50:16 2010 JenneUpdateIOOMirrors moved in prep for round 2 of MC mode measuring

[Jenne, Kevin, Kiwamu]

We moved some optics in preparation for measuring the MC mode after the first MMT curved optic, RoC -5m. 

Kevin and I found the box of DLC (sp?) mounts with the 2" Y1-45P optics in the clean tupperware boxes.  We removed one of the Y1-45P's, and replaced it with the MMT1 -5m optic, which was baked several weeks ago.  We left the Y1-45P on the cleanroom table next to where the MMT optics are.  We placed this MMT mirror in the place it belongs, according to Koji's table layout of the BS table. 

We drag wiped one of the other Y1-45P's that was in the box since it was dirty, and then placed the optic on the IOO table, on the edge closest to the BS table, with the HR side facing the BS table, so that the beam reflected off the curved mirror is reflected back in the direction of the BS table.  This was aligned so the beam hits the same PZT mirror we were using last time, to get the beam out of the BS chamber door.  We left a razor dump on the edge of the BS table, by the door, which will need to be removed before actual measurements can take place. 

Rana pointed out that the anticipated mode calculation should be modified to include the index of refraction of the crystals in the Faraday, and the polarizers in the Faraday.  This may affect where we should put MMT1, and so this should be completed before round 2 measurements are taken, so that we can move MMT1.

Also, the optics are in place now, and the beam is going out the BS chamber door, but we have not yet measured distances (design distances quoted on the MMT wiki page), and confirmed that everything is in the right place.  So there is a bit more work required before beginning to measure round 2.

 

Note:  While I was poking around on the BS table, I had to move several optics so that we could fit MMT1 in the correct place.  When preparing to move these optics, I found 2 or 3 that were totally unclamped. This seems really bad, especially for tall skinny things which can fall over if we have an earthquake.  Even if something is in place temporarily, please clamp it down.

  2991   Wed May 26 14:28:01 2010 KojiUpdateIOOMirrors moved in prep for round 2 of MC mode measuring

That's true. But I thought that you measured the mode after those optics and the effect of them is already included.

So:

  • We need to model the transmissive optics in order to understand the measured mode which is different from the MC mode slightly.
  • We just can calculate the modes based on the measurement in order to figure out the realistic positions of the MMT1 and MMT2.

Quote:

Rana pointed out that the anticipated mode calculation should be modified to include the index of refraction of the crystals in the Faraday, and the polarizers in the Faraday.  This may affect where we should put MMT1, and so this should be completed before round 2 measurements are taken, so that we can move MMT1.

 

  2993   Wed May 26 15:34:00 2010 JenneUpdateIOOMirrors moved in prep for round 2 of MC mode measuring

Quote:

That's true. But I thought that you measured the mode after those optics and the effect of them is already included.

So:

  • We need to model the transmissive optics in order to understand the measured mode which is different from the MC mode slightly.
  • We just can calculate the modes based on the measurement in order to figure out the realistic positions of the MMT1 and MMT2.

Quote:

Rana pointed out that the anticipated mode calculation should be modified to include the index of refraction of the crystals in the Faraday, and the polarizers in the Faraday.  This may affect where we should put MMT1, and so this should be completed before round 2 measurements are taken, so that we can move MMT1.

 

 Yes, the measured mode takes all of this into account.  But in Kevin's plot, where he compares 'measured' to 'expected', the expected doesn't take the Faraday optics into account.  So I should recalculate things to check how far off our measurement was from what we should expect, if I take the Faraday into account.  But for moving forward with things, I can just use the mode that we measured, to adjust (if necessary) the positions of MMT1 and MMT2.  All of the other transmissive optics (that I'm aware of) have already been included, such as the PRM and the BS.  This included already the air-glass curved interface on the PRM, etc.

  5646   Mon Oct 10 18:53:04 2011 KatrinUpdateGreen LockingMirrors whose angle of incidence is not 45

The angle of incidence of light is for some mirrors on the YARM end table different from 45° even though the mirrors are coated for 45°.

The mirrors below are useful if there are plans to replace these mirrors by properly coated ones.

 

Mirror
Angle of incidence (degree)
1st 1" mirror right after laser* 10
2nd 1" mirror right after laser 35
1st 2" steering mirror to vacuum system 15
2nd 2" steering mirror to vacuum system 28

 

* This is the new mirror as decribed on http://nodus.ligo.caltech.edu:8080/40m/5623

 

  10796   Sat Dec 13 14:26:36 2014 ericqUpdateLSCMismatched gains on ETMY Transmon QPD

Yesterday, we were seeing anomalously high low frequency RIN in the y-arm (rms of 4% or so). I swung by the lab briefly to check this out. Turns out, despite TRY of 1.0, there was reasonable misalignment. ASS with the excitation lowered by a factor of two, and overall gain at 0.5 or so aligned things to TRY=1.2, and the RIN is back down to ~0.5% I reset the Thorlabs FM to make the power = 1.0

I then went to center the transmitted beam on the transmon QPD. Looking at the quadrant counts as I moved the beam around, things looked odd, and I poked around a little... 

I strongly suspect that we have significantly mismatched gains for the different quadrants on the ETMY QPD. 

Reasoning: With the y-arm POY locked, I used a lens to focus down the TRY beam, to illuminate the quadrants individually. Quadrants 2 and 3 would go up to 3 counts, while 1 and 4 would go up to 0.3 and 0.6, respectively. (These counts are in some arbitrary units that were set by setting the sum to 1.0 when pitch and yaw claimed to be centered, but mismatched gains makes that meaningless.)

I haven't looked more deeply into where the mismatch is occurring. The four individual whitening gain sliders did affect the signals, so the sliders don't seem sticky, however I didn't check the actual change in gains. Will the latest round of whitening board modifications help this?

Hopefully, once this is resolved, the DC transmission signals will be much more reliable when locking...

  10666   Tue Nov 4 14:46:00 2014 manasaUpdateGreen LockingMissing beatnotes

Summary: Cannot find beatnotes between the arms and PSL.

I wanted to measure the ALS out of loop noise before putting stuff on the PSL table for frequency offset locking.

But I was not able to find the beat notes between the arms and PSL green. All I could find while scanning through the end laser temperatures is the beatnote between the X and Y green.

EricQ says that he spent some time yesterday and could not find the beatnotes as well.

Debugging and still could not find:

1. Checked the FSS slow actuator. This was close to zero ~0.003

2. Checked the green alignment on the PSL table. Everything seems fine.

3. Checked the actual PSL laser temperature. It was 31.28deg and not very far from when it was last set at 31.33deg elog.

4. Also checked the end laser temperatures. Both the lasers are ~40deg (where I could see the beatnote between the arms). Based on the plot here and  here , we are very much in the regime where there should be a beatnote between the PSL and the arms.

  14497   Tue Mar 26 18:35:06 2019 JonUpdateUpgradeModbus IOC is running on c1susaux2

Thanks to new info from Johannes, I was able to finish setting up the modbus IOC on c1susaux2. It turns out the 17 Acromags draw ~1.9 A, which is way more than I had expected. Hence the reason I had suspected a short. Adding a second DC supply in parallel solves the problem. There is no issue with the wiring.

With the Acromags powered on, I carried out the following:

  • Confirmed c1susaux2 can communicate with each Acromag at its assigned IP address
  • Modified the EPICS .cmd file to point to the local modbus installation (not the remote executable on /cvs/cds)
  • Debugged several IOC initialization errors. All were caused by minor typos in the database files.
  • Scripted the modbus IOC to launch as a systemd service (will add implementation details to the documentation page)

The modbusIOC is now running as a peristent system service, which is automatically launched on boot and relaunched after a crash. I'm able to access a random selection of channels using caget.

What's left now is to finish the Acromag-to-feedthrough wiring, then test/calibrate each channel.

  3387   Mon Aug 9 13:32:02 2010 nancyUpdateIOOMode Cleaner ASC

 E-log entry for Friday - will attach more plots to this entry on wednesday after i am back   to the 40.

 
Started working at some 1030 hrs and recording the Open Loop Tfs for all 6 loops.
The control was not so good, and I lost the lock quite a number of times while measureing
WFS  did not converge when the spot was aligned to the center. But there was convergence to a non-center point. So if  the control system was switched on near those points, it was converging to that point.
 
Autolocker : switches WFS control on directly, whereas the best way is to gradually increase the gain to 1. Also, the autolocker code now needs to be changed to incoporate the switing off the MC2 oplev in down and switch it on in the up script.
 
After Koji locked the Reference Cavity in the evening, I resumed measurements for the Open Loop TFs.
 
Measurement of the Open Loop Transfer Functions :
 
 
noise waveform was generated using arbitrary wf generator and injected into each loop.
An LPF was applied to have max co-relation at minimum disturabnce. (thanks to Rana)
The Transfer functions, Co-relations and Power Spectra were then measured using the DTT.
 
 
Power Spectrum of the IN1, IN2 and EXC shows clearly the suppression of the noise, and OLTF shows the phase margins.
 
- Courtesy Rana again for suggesting the idea of plotting power spectra of all signals in the same graph.
 
Later in the night , Koji worked with me and we reflected upon all TFs and changed gains whereevr required according to the phase margin considerations from the Open Loop TFs.
We used the same output matrix given in the previous e-log.   
 
 
Final gains -
 
Alignment Gain in the WFS Master - 1.000
 
Loop Gain
WFS1 P 0.27
WFS1 Y 0.7
WFS2 P 0.15
WFS2 Y 0.110
MC 2OPLEV P -0.1
MC2 OPLEV Y -0.1
 
 
this measurement invloved locking the MC to the correct position, with the spot centered at both the WFS and the QPD. invloved some cheating (offsets) after we tried centering w/o offsets.
demod signal was also centered while alignment.
credits to Koji for getting the correct lock position and also staying with me till late night in the lab
 
Important Points to be noted
 
1. All loops' histories have to be cleared while swtiching them on.
2. turn the loop output before the loop input so that there is no remnant history in the loop.
2. Alignment gain was gradually increased to 1. and tehn the oplevs turned on.
 
 
Later measured teh PSD of  6 error signals under 3 conditions -
 
New Control ON
 
New Control OFF
 
Old Control ON
 
 
Also measured the time series for the MC_trans and MC_refl for the 3 conditions.
 
 
 Status MC_Trans  MC_REF 

  

New Control ON  trans_on.pdf refl_on.pdf   
New Control OFF trans_off.pdf  refl_off.pdf  
Old Control ON trans_old.pdf refl_old.pdf  
 
 
 
 
 
 
 
  

 

Attachment 5: refl_off.pdf
refl_off.pdf
ELOG V3.1.3-