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ID Date Author Type Categoryup Subject
  11997   Wed Feb 17 13:45:15 2016 ericqUpdateGeneralNo monit on frontends

daqd has indeed continued to be unstable. I found system times had drifted apart again... I think something weird happened in the booting of the frontends. The monit processes were not running on any of the frontends. I ntpdate'd again, and manually started monit on each fronted via sudo /etc/init.d/monit start

  12010   Thu Feb 25 11:02:36 2016 SteveUpdateGeneralPower Glitch again
Quote:

Chiara reports an uptime of >195 days, so its UPS is working fine yes

FB, megatron, optimus booted via front panel button.

Jetstor RAID array (where the frames live) was beeping, since its UPS failed as well. The beep was silenced by clicking on "View Events/Mute Beeper" at 192.168.113.119 in a browser on a martian computer. I've started a data consistency check via the web interface, as well. According to the log, this was last done in July 2015, and took ~19 hrs.

Frontends powered up; models don't start automatically at boot anymore, so I ran rtcds start all on each of them. 

All frontends except c1ioo had a very wrong datetime, so I ran sudo ntpdate -b -s -u pool.ntp.org on all of them, and restarted the models (just updating the time isn't enough). There is an /etc/ntp.conf in the frontend filesystem that points to nodus, which is set up as an NTP server, but I guess this isn't working.

PMC locking was hindered by sticky sliders. I burtrestored the c1psl.snap from Friday, and the PMC locked up fine. (One may be fooled by the unchanged HV mon when moving the offset slider into thinking the HV KEPCO power supplies need to be brought down and up again, but it's just the sliders)

Mode cleaner manually locked and somewhat aligned. Based on my memory of PMC camera/transmission, the pointing changed; the WFS need a round of MC alignment and WFS offset setting, but the current state is fine for operation without all that. 

10:15 power glitch today. ETMX Lightwave and air conditions turned back on

Attachment 1: powerGlitch.png
powerGlitch.png
  12011   Thu Feb 25 11:32:04 2016 gautamUpdateGeneralPower Glitch again

 

Quote:

10:15 power glitch today. ETMX Lightwave and air conditions turned back on

The CDS situation was not as catastrophic as the last time, it was sufficient for me to ssh into all the frontends and restart all the models. I also checked that monit was running on all the FEs and that there was no date/time issues like we saw last week. Everything looks to be back to normal now, except that the ntpd process being monitored on c1iscex says "execution failed". I tried restarting the process a couple of times, but each time it returns the same status after a few minutes.

  12043   Wed Mar 23 11:55:47 2016 SteveUpdateGeneral Smart UPS 2200 Battery Replaced

Batteries replaced in control room UPS after 3 years from replaceUPSbattery.com

 

 

  12052   Mon Mar 28 22:16:44 2016 KojiUpdateGeneralNew WiFi router

I configured three more mini wifi extender. They are ready to use.

We should add these to the host table (I forgot where it is)

192.168.113.233 NETGEAR_EX3700_1
192.168.113.234 NETGEAR_EX3700_2
192.168.113.235 NETGEAR_EX3700_3
192.168.113.236 NETGEAR_EX3700_4

  12076   Thu Apr 14 17:30:18 2016 ericqUpdateGeneralPLL measurement ongoing

Just a heads up that some equipment is hooked up at the PSL table for the repaired AUX laser PLL measurement, I plan to continue with it tonight.

I've taken a few spectra that, along with the PZT coefficient from the repair sheet, that suggest the noise level is ok (incoherent sum of AUX and PSL at about ~3e4 / f Hz/rtHz), but calibrated plots, etc. will follow in time.

  12077   Fri Apr 15 03:02:44 2016 ericqUpdateGeneralNew AUX laser measurements

The free running PSL+AUX beat frequency noise spectrum has been measured via PLL. AUX laser PZT PM and AM responses were measured too. 


Rough notes about these measurements:

Laser -> QWP -> HWP -> PBS -> 10% BS -> Beat
3.4Vpp out of PD, (40% contrast)
20dB Coupler, output to analyzer, coupled output to Mixer (-a few dBm, didn't check specifically)
Mixer: ZP-3+, BLP-5.1 at output
LO: OCXO @ 36MHz 13dBm->5dB Att-> +8dBm LO at Mixer

Got ~65mVpp out of Mixer

Mixer out -> SR560, LP 3Hz, G=500 -> Pomona Summing node -> Laser PZT
~30kHz UGF ~30 deg phase

Spectra, OLG via SR785 taken with free running PSL, anthropomorphic temperature servo. Data sheet calibration used for PZT. SR560 output noise dominates over analyzer, mixer, PD. Spectrum looks ok, I think.

PM measured with AG4395. High impedance probe used for laser PZT, otherwise couldn't lock. PM calibrated via mixer voltage span for fringe-to-fringe. 

PSL beam blocked, AUX power increased to read 8.0V, AM measured with AG4395.

AM/PM doesn't look to dissimilar to old measurements on wiki. ~230kHz looks like a fine modulation freq. 

Still to be done to AUX laser:
- joint PSL/AUX temperature sweeps
- Output power vs. diode current
- Beam profile

Attachment 1: aux_innolight_freqPSD.pdf
aux_innolight_freqPSD.pdf
Attachment 2: aux_innolight_AMPM.pdf
aux_innolight_AMPM.pdf
Attachment 3: aux_innolight_data.zip
  12078   Fri Apr 15 18:35:57 2016 gautamUpdateGeneralNew AUX laser measurements

I've performed the temperature sweep of PSL vs Innolight 1W AUX laser.

  • I followed the procedure in this elog - started by turning of FSS and FSS Slow servos, closed the PSL shutter, noted down the value of PSL temperature
  • As noted in elog 3759, there are multiple temperatures at which a beat can be found. I recorded all that I could find. The IR beat frequency was < 20MHz at the temperatures recorded (and had an amplitude of a few dBm, but I used a 20dB coupler to look at the signal on the HP spectrum analyzer
  • The PMC unlocked each time I changed the PSL temperature, but the PMC autolocker worked for me every time
  • We should use curve 3 in attachment 1, it is the most reliable set of temperatures at which a beat can be found
  • PSL diode current was 2.100A, AUX laser diode current was 2.001A
  • Attachment 2 is the data

It remains to measure the output power vs diode current, and the beam profile. I will do the latter on the SP table where there is a little more space. Because we have 1W from this NPRO, the knife-edge method requires a power meter that has a large dynamic range and is sensitive enough to profile the beam accurately. After consulting the datasheets of the power meters we have available (Scientech, Ophir and Coherent) together with Koji, I have concluded that the Coherent calorimeter will be suitable. Its datasheet claims it can accurately measure incident powers of up to 100uW, although I think the threshold is more like 5-10mW, but this should still be plenty to get sufficient resolution for a Gaussian intensity profile with peak intensity of 1W. We also checked that the maximum likely power density we are likely to have during the waist measurement process (1W in a beam of diameter 160um) is within the 6kW/cm^2 quoted on the datasheet.

Attachment 1: PSL_AUX_TEMP_SCAN.pdf
PSL_AUX_TEMP_SCAN.pdf
Attachment 2: PSL_AUX_TEMP_SCAN.mat
  12080   Fri Apr 15 23:11:49 2016 gautamUpdateGeneralInnolight 1W moved to SP table

I have moved the 1W Innolight + controller from the PSL table to the SP table for beam profiling.

  12081   Mon Apr 18 00:29:00 2016 gautamUpdateGeneralBeam profiling + injection current scan

Summary

I've finished up the remaining characterization of the repaired 1W Innolight NPRO - the beamscan yielded results that are consistent with an earlier beam-profiling and also the numbers in the datasheet. The output power vs diode current plot is mainly for diagnostic purposes in the future - so the plot itself doesn't signify anything, but I'm uploading the data here for future reference. The methodology and analysis framework for the beamscan is the same as was used here.

Attachment #1 - Beam-scan results for X-direction

Attachment #2 - Beam-scan results for Y-direction

Attachment #3 - Beam profile using fitted beam radii

Attachment #4 - Beam-scan data

Attachment #5 - Output power vs Injection current plot

Even though I remember operating at a diode current of 2.1A at some point in the past, while doing this scan, attempting to increase the current above 2.07A resulted in the "Clamp" LED on the front turning on. According to the manual, this means that the internal current limiting circuitry has kicked in. But I don't think this is a problem as we don't really even need 1W of output power. This is probably an indicator of the health of the diode as well?

Attachment #6 - Output power vs Injection current data

It remains to redo the mode-matching into the doubling oven and make slight modifications to the layout to accommodate the new laser + beam profile. 

I plan to do these in the morning tomorrow, and unless there are any objections, I will begin installing the repaired 1W Innolight Mephisto on the X endtable tomorrow (18 April 2016) afternoon. 

 
Attachment 1: BeamScan_x.pdf
BeamScan_x.pdf
Attachment 2: BeamScan_y.pdf
BeamScan_y.pdf
Attachment 3: ZScan.pdf
ZScan.pdf
Attachment 4: BeamScan.mat
Attachment 5: Innolight_Current_Scan.pdf
Innolight_Current_Scan.pdf
Attachment 6: Innolight_Current_Scan.mat
  12091   Wed Apr 27 09:05:10 2016 SteveUpdateGeneralAP viewport

                   Sad situation

    The anti-symmetric port

spider webs fly in the wind

Attachment 1: APg.jpg
APg.jpg
Attachment 2: AP.jpg
AP.jpg
Attachment 3: APspiderWebs.jpg
APspiderWebs.jpg
  12093   Wed Apr 27 14:06:31 2016 ranaSummaryGeneralmeeting notes
  1. Gautam will get help from Johannes and finish EX table by Monday.
  2. Steve will spend a day this week with Johannes on Green Monster bakeout.
  3. Q to analyzed green PDH servo and design demod low pass. Should we use the double LC notches to notch the 2f product? What's the demod filter attenuation requirement?
  4. Koji will make a drawing of the ruby suspension standoff prism and post into the elog so that Steve can get some quotes next week.
  5. Rana to implement 40m configuration in FOGprime17 and analyze RoC matching of ETMs. Get Antonio's help to analyzed SRC stability. Maybe use PyKat and Finesse since Antonio knows that stuff.
  6. Give OCXO boxes to WB refcav people. Rana get Rich to make another couple of boxes for 40m PMC, FSS, IMC.
  7. Rana/Koji get EKG to make specs and procure some new folding mirrors for the PRC/SRC. Make them a bit concave and dichroic.
  12118   Tue May 17 05:50:43 2016 Varun KelkarUpdateGeneralSURF 2016

Hello, I am Varun Kelkar. I will be working at the 40m lab as a SURF student this summer with Eric Quintero on Audio processing for real time control system signals. This week I will mostly be working on implementing basic DSP C-code offline. Currently I am trying to write a code for noise whitening.

-Varun

  12121   Wed May 18 17:42:52 2016 VarunUpdateGeneralSURF 2016

Finished writing the code on whitening. I have to still test it. uploaded on github noise cancellation repo. @eric could you give me some data of noise power spectral density for testing the code?

-Varun

Quote:

Hello, I am Varun Kelkar. I will be working at the 40m lab as a SURF student this summer with Eric Quintero on Audio processing for real time control system signals. This week I will mostly be working on implementing basic DSP C-code offline. Currently I am trying to write a code for noise whitening.

-Varun

 

  12123   Fri May 20 00:06:19 2016 VarunUpdateGeneralSURF 2016

I have written a basic version of AGC, and have done some tests with a data file. will do tests on whitening and agc today. Also, today I have to go to the SSN office. Hence will be late.

 

-Varun

Quote:

Finished writing the code on whitening. I have to still test it. uploaded on github noise cancellation repo. @eric could you give me some data of noise power spectral density for testing the code?

-Varun

Quote:

Hello, I am Varun Kelkar. I will be working at the 40m lab as a SURF student this summer with Eric Quintero on Audio processing for real time control system signals. This week I will mostly be working on implementing basic DSP C-code offline. Currently I am trying to write a code for noise whitening.

-Varun

 

 

  12127   Mon May 23 17:47:51 2016 VarunUpdateGeneralSURF 2016

Tested the AGC today with LSC cavity transmission signal and error signal. Not in real time still.

Key to attachments:

cav_tr-eps-converted-to.pdf: LSC cavity transmission signal input

cav_tr_out-eps-converted-to.pdf: LSC cavity transmission signal, output of the AGC.

Attachment 1: cav_tr-eps-converted-to.pdf
cav_tr-eps-converted-to.pdf
Attachment 2: cav_tr_out-eps-converted-to.pdf
cav_tr_out-eps-converted-to.pdf
Attachment 3: err-eps-converted-to.pdf
err-eps-converted-to.pdf
Attachment 4: err_out-eps-converted-to.pdf
err_out-eps-converted-to.pdf
  12132   Wed May 25 02:54:09 2016 ericqUpdateGeneralOdds and ends

WFS locking point seemed degraded; I hand aligned and reset the WFS offsets as usual.

ITMX oplev recentered. While doing so, I noticed an ETMX excursion rear its head for the first time in a long while :crying

There was no active length control on ETMX, only OSEM damping + oplevs. Afterwards, its still moving around with only local damping on. I'm leaving the oplevs off for now.

  12135   Wed May 25 14:21:29 2016 Max IsiUpdateGeneralSummary page configuration

I have modified the c1summary.ini and c1lsc.ini configuration files slightly to avoid overloading the system and remove the errors that were preventing plots from being updated after certain time in the day.

The changes made are the following:
1- all high-resolution spectra from the Summary and LSC tabs are now computed for each state (X-arm locked, Y-arm locked, IFO locked, all);
2- I've removed MICH, PRCL & SRCL from the summary spectrum (those can still be found in the LSC tab);
3- I've split LSC into two subtabs.

The reason for these changes is that having high resolution (raw channels, 16kHz) spectra for multiple (>3) channels on a single tab requires a *lot* of memory to process. As a result, those jobs were failing in a way that blocked the queue, so even other "healthy" tabs could not be updated.

My changes, reflected from May 25 on, should hopefully fix this. As always, feel free to re organize the ini files to make the pages more useful to you, but keep in mind that we cannot support multiple high resolution spectra on a single tab, as explained above.

  12136   Wed May 25 14:29:31 2016 VarunUpdateGeneralSURF 2016

Edited the AGC to include overlapping frames yesterday. forgot to put an elog on it!

Quote:

Tested the AGC today with LSC cavity transmission signal and error signal. Not in real time still.

Key to attachments:

cav_tr-eps-converted-to.pdf: LSC cavity transmission signal input

cav_tr_out-eps-converted-to.pdf: LSC cavity transmission signal, output of the AGC.

 

  12137   Thu May 26 18:10:48 2016 VarunUpdateGeneralSURF 2016

Wrote and tested a function for downconversion. It contains a mixer with a sinusoidal input for modulation with the desired frequency and a 2nd order butterworth low pass filter to remove the higher frequency-shifted part of the modulated signal. I have tested this with input of 2kHz giving a good output of 200 Hz on the speaker. Codes are uploaded on github, will update the real time document tomorrow.

 

-Varun

Quote:

Edited the AGC to include overlapping frames yesterday. forgot to put an elog on it!

Quote:

Tested the AGC today with LSC cavity transmission signal and error signal. Not in real time still.

Key to attachments:

cav_tr-eps-converted-to.pdf: LSC cavity transmission signal input

cav_tr_out-eps-converted-to.pdf: LSC cavity transmission signal, output of the AGC.

 

 

Attachment 1: input.png
input.png
Attachment 2: output.png
output.png
  12139   Fri May 27 11:54:22 2016 VarunUpdateGeneralPackage delivery

A package labelled 'UPS Ground' has arrived.

-Varun

  12143   Wed Jun 1 11:19:14 2016 VarunUpdateGeneralUpdate of work till now

Completed:

Wrote and tested a code for AGC using cavity transmission signal and length error signal.

Wrote and tested a code for frequency shifting (downconversion) using mixing and LPF

Wrote a code for whitening using FFT.

Altium working on cit40m iMac

Plans:

Writing codes for Frequency warping and whitening in time domain.

Implement AGC and frequency shifting on the real time control system.

Calculate requirements for Anti-aliasing filter.

  12150   Fri Jun 3 17:56:14 2016 VarunUpdateGeneralDAFI update

Wrote and tested a phase vocoder, with two of its applications:

1) Time scaling: This enables change of time duration without affecting the pitch.

2) Frequency warping: This changes the pitch of the sound without affecting the time duration.

1 & 2 tested offline with cavity transmission signal. 1) gives speedup of 2, and 2 gives frequency warping (pitch lowering by a factor of 2)

codes uploaded on github repo

  12153   Tue Jun 7 17:21:13 2016 AakashUpdateGeneralSURF 2016

Hi!

I am Aakash Patil. I will be working at the 40m lab as a SURF student with Gautam Venugopalan on enclosures for seismometers to shield them from thermal and magnetic fluctuations. This week I will be working on the development of hardware for four probe measurement along with a constant current source. It will effectively help us in accurate temperature measurement throughout the development of enclosure.

 

  12154   Tue Jun 7 18:20:18 2016 VarunUpdateGeneralDAFI update

Tried to implement AGC on FE. Had some trouble bringing the code into the correct form. It looks okay now. However, this agc code as well as idenntity code (input = output) doesnt seem to build on the c1lsc FE. Have not tried too many debugging steps yet, will come and check the problem tomorrow. 

-Varun

Quote:

Wrote and tested a phase vocoder, with two of its applications:

1) Time scaling: This enables change of time duration without affecting the pitch.

2) Frequency warping: This changes the pitch of the sound without affecting the time duration.

1 & 2 tested offline with cavity transmission signal. 1) gives speedup of 2, and 2 gives frequency warping (pitch lowering by a factor of 2)

codes uploaded on github repo

 

  12159   Wed Jun 8 16:12:38 2016 VarunUpdateGeneralDAFI update

Summary: I am implementing digital audio filtering on various interferometer signals in order to listen to the processed audio which will help in characterizing and noise reduction in the interferometer. Following is an implementation of an Automatic Gain control (AGC) block on an LSC input signal.

Details of AGC: Currently, the AGC code implemented on FE takes input to fill a frame, then calculates the power in each frame and gives an appropriate gain to it, so that the new power content is to the required level. It is then written to the output, frame by frame. The frame is currently a rectangular window. The frame length and hop size can be adjusted. Current values are as follows:

frame length is 512 samples

hop length is 128 samples.

The input and output are delayed by 1 frame.

Details of testing: Attachment 1 shows a simulink diagram of the DAF system. Eric made this and I modified it later on. Testing was done using signal from the "LSC1" channel. Attachments 2 and 3 show aquired input and output of the AGC respectively. Gain of the preamp of the LSC input signal was varied over a total time span of 200 s. Each gain value was kept for a duration of about 20 seconds. The varying power levels can be seen in the input plot.

The output shows a uniform power level throughout.

 

Quote:

Tried to implement AGC on FE. Had some trouble bringing the code into the correct form. It looks okay now. However, this agc code as well as idenntity code (input = output) doesnt seem to build on the c1lsc FE. Have not tried too many debugging steps yet, will come and check the problem tomorrow. 

-Varun

Quote:

Wrote and tested a phase vocoder, with two of its applications:

1) Time scaling: This enables change of time duration without affecting the pitch.

2) Frequency warping: This changes the pitch of the sound without affecting the time duration.

1 & 2 tested offline with cavity transmission signal. 1) gives speedup of 2, and 2 gives frequency warping (pitch lowering by a factor of 2)

codes uploaded on github repo

 

 

Attachment 1: dafi.png
dafi.png
Attachment 2: agcin.pdf
agcin.pdf
Attachment 3: agcout.pdf
agcout.pdf
  12160   Thu Jun 9 09:57:06 2016 AakashUpdateGeneralSeismometer Enclosure Development
Me and Gautam yesterday opened the tilt-free seismometer enclosure to see if we could use the thermocouples and
other things previously used by Megan. But we are planning to get new four-wire RTDs for our work.
For the next day or two, I will be trying to set up Acromag Busworks terminal so that the data logging during
this enclosure development experiment becomes perfect and easy. Johannes has sent me the wiki page URL for the same.
  12163   Thu Jun 9 18:54:40 2016 AakashUpdateGeneralAbout Acromag | SURF 2016

Today I tried to setup Acromag Busworks card. I was able to calibrate and test it over USB but I couldn't test it over ethernet. I'll utilize a few hours tomorrow to test it over ethernet and see if I can make it work. I have also found a few RTDs which I want to use for temperature sensing via four probe method. So, tomorrow I'll get these RTD details revived by Gautam and Steve.

I was wondering if we have a basic DAQ card with maybe 4 channels which is simple to setup like NI DAQ cards.

  12172   Mon Jun 13 19:30:58 2016 AakashUpdateGeneralEPICS Installation | SURF 2016

About acquiring data: Initially I couldn't start with proper Acromag setup as the Raspberry pi had a faulty SD card slot. Then Gautam gave me a working pi on which I tried to install EPICS. I spent quite a time today but couldn't setup acromag over ethernet.  But, it would be great if we have a USB DAQ card. I have found a good one here http://www.mccdaq.com/PDFs/specs/USB-200-Series-data.pdf It costs around 106$ including shipping (It comes with some free softwares for acquiring data) . Also, I know an another python based 12bit DAQ card (with an inbuilt constant current source) which is made by IUAC, Delhi and more information can be found here http://www.iuac.res.in/~elab/expeyes/Documents/eyesj-progman.pdf  It costs around 60$ including shipping.

About temperature sensing: The RTD which I found on Omega's list is having a temperature resolution of 0.1 deg C. I have also asked them for the one with good resolution. Also according to their reply, they have not performed any noise characteristics study for those RTDs.

 

  12176   Tue Jun 14 11:52:08 2016 JohannesUpdateGeneralEPICS Installation | SURF 2016

We generally want to keep the configuration of the 40m close to that of the LIGO sites, which is why we chose BusWorks, and it is also being established as a standard in other labs on campus. Of course any suitable DAQ system can do the job, but to stay relevant we generally try to avoid patchwork solutions when possible. Did you follow Aidan's instructions to the book? I haven't set up a system myself, yet, so I cannot say how difficult this is. If it just won't work with the Raspberry Pi, you could still try using a traditional computer.

Alternatively, following Jamie's suggestions, I'm currently looking into using python for the modbus communications (there seem to be at least a few python packages that can do this), which would reportedly make the interfacing and integration a lot easier. I'll let you know when I make any progress on this.

Quote:

About acquiring data: Initially I couldn't start with proper Acromag setup as the Raspberry pi had a faulty SD card slot. Then Gautam gave me a working pi on which I tried to install EPICS. I spent quite a time today but couldn't setup acromag over ethernet.  But, it would be great if we have a USB DAQ card. I have found a good one here http://www.mccdaq.com/PDFs/specs/USB-200-Series-data.pdf It costs around 106$ including shipping (It comes with some free softwares for acquiring data) . Also, I know an another python based 12bit DAQ card (with an inbuilt constant current source) which is made by IUAC, Delhi and more information can be found here http://www.iuac.res.in/~elab/expeyes/Documents/eyesj-progman.pdf  It costs around 60$ including shipping.

About temperature sensing: The RTD which I found on Omega's list is having a temperature resolution of 0.1 deg C. I have also asked them for the one with good resolution. Also according to their reply, they have not performed any noise characteristics study for those RTDs.

 

 

  12186   Thu Jun 16 08:52:14 2016 SteveUpdateGeneralilluminators turned off

PSL, BS, ITMY and ETMX the illuminators were left on over night.

  12213   Thu Jun 23 17:24:32 2016 ericqUpdateGeneralTweaks

I spent some time this afternoon reviving some of my CESAR/ESCOBAR shenanigans on the Y arm. I found it neccesary to adjust a few things.

  • PMC realigned 
  • ETMY oplev centered
  • Y End green realigned
  • PSL/Y Green beat realigned

Afterwards, ALSY noise levels were good. 

  12217   Mon Jun 27 15:47:17 2016 SteveUpdateGeneralQPR clean room gloves

I got some QPR Nitrile gloves. They are LIGO approved.White nitrile gloves are naturally anti-static- 109 ohms

Their touch not as good as laytex  gloves but try to use them.

 

  12220   Tue Jun 28 16:09:41 2016 PrafulUpdateGeneral40m Summary Pages

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

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

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

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

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

  12224   Tue Jun 28 22:54:43 2016 AakashUpdateGeneralSeismometer Enclosure Development | SURF 2016

The existing enclosure for seismometer at LIGO 40m lab is a cylindrical stainless steel can placed upside down over the seismometer. It has more empty space between the seismometer and the internal surface of enclosure which is not desirable(I'll quantitatively elaborate this statement once my temperature measuring setup is ready).

 

Stainless steel has a thermal conductivity in the range of 16.3 to 16.7 W/m/K and magnetic permeability 1.260e-6 H/m.Assuming an ambient temperature 298K, and the temperature inside the enclosure as 295K, as well as substituting all the values for dimesions and material properties of existing enclosure,
k=16.4 W/mK, μ=1.260e-6 H/m, L=2ft=0.6096m, b=r2 =0.5ft=0.1524m, thickness=5mm, a=r1 =0.1474m.
So by using the textbook relations(I have mentioned them in my report), the value of attenuation coefficient is 5.953584e-05 and the value of rate of heat transfer= 5.64913 kW. The attenuation coefficient value is quite better for steel but proper care needs to be taken to avoid heat transfer. For studying the variation of rate of heat transfer and attenuation with the thickness of enclosure material, I have plotted the following attached graphs for different materials which include hardened stainless steel, aluminium, pure iron and nanoperm-muMetal.

 

 

About Data Acquisation

I have already invested a lot of time to configure and use acromag busworks card over ethernet. So now I have made an arrangement to measure temperature by AD592CNZ temperature transducer IC. I would be using raspberry pi for acquiring data untill I figure out a way to use acromag busworks card for the same. This setup of acquiring logging temperature using raspberry pi is mostly ready except the calibration part.

  12225   Wed Jun 29 00:09:36 2016 AakashUpdateGeneralThings from past | SURF 2016

I have taken out the heaters and temperature sensors from the enclosure which was made by Megan last summer. Soon I will test and configure those heaters.

  12233   Thu Jun 30 16:11:57 2016 ericqUpdateGeneralVent Prep

I have updated the vent prep checklist on the wiki. Gautam and I did the following things from it:

  • Center all oplevs, transmon QPDs 
    • ETMX oplev has not been centered, since it's moving around so much, and we're going to immediately move the suspension anyways.
  • Align the arm cavities for IR and align the green lasers to the arms. 
    • AUX X Green was aligned while the X arm was well aligned. Soon thereafter, ETMX wandered away, but the green will remain a good reference
  • Update the SUS Dritmon values 
  • Reconcile all SDF differences 
  • Reduce input power to no more than 100mW by adjusting wave plate+PBS setup on the PSL table BEFORE the PMC. (Using the WP + PBS that already exist after the laser.) 

  • Replace 10% BS before MC REFL PD with Y1 mirror and lock MC at low power.
    • I don't think we've vented since the most recent slew of changes to the IMC servo, so its not surprising that the current low power scripts don't work. I'm working on locking the IMC, but this does not prevent us from initiating the vent tomorrow.

 

The following bullets have not yet been executed:

  • Close shutter of PSL-IR and green shutters at the ends 
  • Make sure the jam nuts are protecting bellows 
  • Check crane functionality & cleanliness 

  • Turn off HV into vacuum: OMC is not wired this time 
  • Particle count must be under 10,000 counts / cf min for 0.5 micron 
  • Check all metal window covers are on. 
  • Check 5 cylinders (24 cft size) of instrument grade air, called Alfa Gas 1 in stock.
  12235   Thu Jun 30 21:24:36 2016 ericqUpdateGeneralVent Prep

Steve has ordered some teflon parts to take the place of the metal parts in his acetone-soaking jig. They should arrive tomorrow. 

So, we will be begin the venting process tomorrow. Doors to come off on Tuesday.

  12236   Fri Jul 1 01:52:54 2016 AakashUpdateGeneralSeismometer Enclosure Development | SURF 2016

I have transferred most of the temperature measurement stuff from the front area to seismometer at the end of Y-arm.  While arranging the components I have taken all care that they will not interfere with existing system. Also, I have temporarily taken a monitor from the front area to the area near same seismometer as I couldn't talk to Rpi via ssh. For next twelve hours, I am now recording temperature inside as well as outside the seismometer enclosure. Some temperature sensors are inside the enclosure while some are outside the seismometer enclosure.

 

  12240   Mon Jul 4 10:30:37 2016 ericqUpdateGeneralPreliminary vent plans

Here are some plans / rough procedures for this week's vent. It is unlikely that I have though of everything, but this should be a reasonable starting point.

The mode cleaner still hasn't been locked in air, we may not want to touch the Y arm optics until we are able to lock to the Y arm and dither align, so we are sure to keep the input pointing from drifting away too much.


Primary objectives:

  • Re-suspend ETMX
  • First contact of all arm cavity optics

Secondary objectives:

  • Install new gauges
  • Replace 40mm baffles with 50mm baffles
  • Check cleanliness of inner viewport surfaces

ETMX project

  • Open ETMX chamber
  • Take all manner of photos of ETMX suspension in-situ
    • If some kind of obvious issue is evident, fix it, proceed accordingly
  • Mark suspension position
  • Move suspension to edge of the table, more pictures + inspection
  • Move suspension to flow bench, remove optic
  • Transport optic to clean room
  • Acetone soaking / standoff removal
  • Re-glue side magnet
  • Re-glue guide rod + standoff
  • OSEM transplant from old to new suspension
  • Suspend, following SOS suspension procedure
  • Drive optic around, see if jumps are evident
  • Clean with first contact
  • Reinstall optic, align, etc.

Optic cleaning

For $optic in [ITMX, ITMY, ETMY]:

  • Open chamber
  • Take many, many pictures
  • Mark suspension position
  • move suspension to edge, take pictures of HR surfaces
  • Mark OSEM orientation, remove oems
  • Clean AR and HR surfaces with first contact
  • Reinstall OSEMS at proper position, rotate to minimize bounce/roll coupling
  • Reinstall optic, align, etc.
  12243   Tue Jul 5 17:14:02 2016 ericqUpdateGeneralVent progress

Rough summary of today's progress:

  • IMC locked, reasonably aligned. (Only have MC2 trans reference, no WFS)
    • FSS Slow lock threshold got lowered to 1k MC2 trans
    • Autolocker doesn't really work, though I made some modifcations to it that reflect the manual locking that works
  • TTs, PRMI optics moved around until AS and REFL spots looked good. 
    • Small flashes visible in TRY
    • ND filter on Y transmon QPD removed, since we have so little light
  • Y arm was not locked, but this was deemed suitable to proceed
  • Heavy doors taken off ETMX and ITMX chambers, light doors put on.
  • Went into ETMX chamber, poked around, took a bunch of pictures (Gautam is uploading has uploaded to picasa (foteee account), the two best ones of the stand-offs on either side are attached, although I guess we can't really conclude anything from these except that on the side with the OSEM, there seems to be a few extra stray bits of epoxy residue...)
  • Removed ETMX side OSEM to get a picture of that side of optic (it is currently off, ETMX watchdog shutdown for now...)
  • Checked that table is level with clean spirit level (it was to within the resolution of the spirit level which is quoted as 0.42mm/m)

I didn't really see anything out of the ordinary on the ETMX suspension. Earthquake stops had clearance, OSEMS were secure, no visible glue degredation on face magnets. Inspection with green LED flashlight didn't reveal any obscene dirtieness on either face, just a few particles here and there. The top of the opic barrel unsurprisingly has a good amount of particulate. The wire grooves are way too small to resolve anything at this point, other than that they exist.

The suspension footprint is already marked, tomorrow we can move the suspension closer to the door to get an even closer look at it, before removing it from the chamber. 

Attachment 1: noOsemSide.JPG
noOsemSide.JPG
Attachment 2: OSEMside.JPG
OSEMside.JPG
  12245   Tue Jul 5 19:10:41 2016 ranaUpdateGeneralVent progress

I'd suggest clamping and moving it to the flow bench so you can inspect with a bright light. Then remove the wire and inspect the standoff, but hurry up with getting it in the soak bath so you can start on the cleaning of the other ones.

I wonder if we're really sure that its a mechanical problem with ETMX.

Gautam tells me that the local damping was always ON when looking for the jumps. This means that the coil driver was still hooked up and we can't rule out glitches in the DAC or the coil driver.

The UL OSEM shows the biggest movement (10 microns). The LR shows the second most (6-7 microns). The others are 2x less. So its consistent with a voltage change on UL,

Is this consistent with a slip in one of the wire standoffs? I think no.

 

Attachment 1: jumpEvent20151105.png
jumpEvent20151105.png
  12246   Tue Jul 5 21:51:35 2016 ericqUpdateGeneralVent progress

One glitch was seen to occur without a change in the output voltage monitors in ELOG 11744

  12247   Tue Jul 5 23:38:42 2016 gautamUpdateGeneralVent progress - ETMX SUS Coil driver electronics investigation

With Koji's help, I've hacked together an arrangement that will allow us to monitor the output of the coil driver to the UL coil. 

The arrangement consists of a short custom ribbon cable with female DB25 connectors on both ends - the particular wire sending the signal to the UL coil has a 100 ohm resistor wired in series, because the coil has resistance ~20ohm, and the output of the coil driver board has a series 200(?) ohm resistor, so by directly monitoring the voltage at this point, we may not see a glitch as it may register too small. Tangentially related: the schematic of the coil driver board suggests that the buffered output monitor has a gain of 0.5. 

To monitor the voltage, I use the board to which the 4 Oplev signals are currently hooked up. Channel 7 on this particular board (corresponding to ADC channel 30 on c1scx) was conveniently wired up for some prior test, so I used this channel. Then, I modified the C1SCX model to add a testpoint to monitor the output of this ADC. Then, I turned OFF the input on the coil output filter for the UL Coil (i.e. C1:SUS-ETMX_ULCOIL_SW1) so that we can send a known, controlled signal to the UL Coil by means of awggui. Next, I added an excitation at 5 Hz, amplitude 20 counts (as the signal to the coil under normal conditions was approximately of this amplitude) to the excitation channel of the same filter module, which is the state I am leaving the setup in for the night. I have confirmed that I see this 5Hz oscillation on the monitor channel I set up. Oddly, the 0 crossings of the oscillations happen at approximately -1000 counts and not at 0 counts. I wonder where this offset is coming from? The two points I am monitoring the voltage across is shown in the attached photograph - the black clip is connected to the lead carrying the return signal from the coil.

I also wanted to set up a math block in the model itself that monitors, in addition to the raw ADC channel, a copy from which the known applied signal has been cancelled, as presumably a glitch would be more obvious in such a record. However, I was unable to access the excitation channel to the ULCOIL filter from within the SCX model. So I am just recording the raw output for tonight...

Attachment 1: image.jpeg
image.jpeg
  12249   Wed Jul 6 09:34:26 2016 SteveUpdateGeneralPRM sensing voltage LR

Yesterday Q noticed that PRM_sensor_LR was 0.098V  This actually went to ~ zero on 7-3

 

Attachment 1: PRM_LR.png
PRM_LR.png
  12253   Wed Jul 6 16:40:09 2016 AakashUpdateGeneralSeismometer Enclosure Development | SURF 2016

I am using AD592CNZ temperature transducer ICs for measuring temperature inside as well as outside the enclosure. It is a  current output IC which outputs current proportional to temperature. As mentioned in the data sheet of AD592, I am using the following two schematics:

 

Though I still need to calibrate these temperature transducers, I did some measurements. I have temperature readings, and now my goal in few days is to find a transfer function of temperature fluctuations inside the enclosure to outside the enclosure.

 

About data acquisition:

We have re-configured the raspberry pi(B8:27:EB:70:D0:D8) on martian network. It's new ip address is 192.168.113.107(domenica.martian). Also, we have added the Acromag Busworks card(00:01:C3:00:9F:C8) on the martian network and its ip address is 192.168.113.237(acroey.martian).   

  12255   Wed Jul 6 19:36:45 2016 KojiUpdateGeneralSUS Vmon

I wanted to know what this Vmon exactly is. D010001 is telling us that the Vmon channels are HPFed with fc=30Hz (Attachment 1). Is this true?


I checked the quiscent noise spectrum of the ITMX UL coil output (C1:SUS-ITMX_ULCOIL_OUT) and the corresponding VMON (C1:SUS-ITMX_ULVmon). (Attachment 2 Ref curves). I did not find any good coherence. So the nominal quiscent Vmon output is carrying no useful information. 

Question: How much do we need to excite the coil output in order to see any meaningful signal?

As I excite the ITMX UL coil (C1:SUS-ITMX_ULCOIL_EXC) with uniform noise of 100-300 counts below 0.3Hz, I eventually could see the increase of the power spectrum and the coherence (Attachment 2). Below 0.1 Hz the coherence was ~1 and the transfer function was measured to be -75dB and flat. But wait, why is the transfer function flat?

In fact, if I inject broadband noise to the coil, I could increase the coil output and Vmon at the same time without gaining the coherence. (Attachment 3). After some more investigation, I suspect that this HPF is diabled (= bypassed) and aliasing of the high freq signal is causing the noise in Vmon.

In order to check this hypothesis, we need to visit the board.

Attachment 1: HPF.png
HPF.png
Attachment 2: 160706_ITMX_VMON2.pdf
160706_ITMX_VMON2.pdf
Attachment 3: 160706_ITMX_VMON1.pdf
160706_ITMX_VMON1.pdf
  12256   Wed Jul 6 20:51:00 2016 KojiUpdateGeneralSeismometer Enclosure Development | SURF 2016

Circuit1: It is nice to receive the voltage across the transimpedance resistor with a high impedance buffer (or amplifier), as close to the resister as possible. This amplifier needs to have low numbers for input bias current, input offset current, and input current noise. These current noise becomes the noise of the temperature reading. On the top of that, the input voltage noise of the buffer will be added to the output. The typical noise model can be found in http://www.analog.com/media/en/technical-documentation/application-notes/AN-940.pdf

The good candidates for the buffer is LT1128, ADA4004, OPA140, and LT1012. If the application is not too sensitive to the total noise, OPA604 is a good choise with easier handling.

Circuit2: With the same reason, AD741 is an old generic amp that is not a great choise for this purpose. The current noise is more significant because of the higher transimpedance here. The same noise model as above can be used to analyze the performance.

ELOG V3.1.3-