You don't need the fourth glass piece on the diamond beam dump.

[JC, Paco]

I tried restarting all models this afternoon to see if the DC error 0x2000 on c1cal model cleared (currently no frame data is being written from c1cal). By running ./restartAllModels.sh on the scripts/cds/ folder, and then BURT restoring, but unfortunately this didn't work. I also tried restarting DAQD without success. Finally, I guess since the error has been related to channel inconsistencies in the model's .INI file (what where when?) I tried rtcds build c1cal and rtcds install c1cal and then another full restart. No success.

[Paco, Anchal]

Paco accidentally clicked on C1:SUS-MC1_UL_TO_COIL_SW_1_1 (MC1 POS to UL Coil Switch) and clicked it back on. We didn't see any loss of lock or anything significant on the large monitor on left.

Testing the new calculated input matrix

• Switched off the PSL shutter (C1:PSL-PSL_ShutterRqst)
• Switched off IMC autolocker (C1:IOO-MC_LOCK_ENABLE)
• Uploaded the same input matrix as the current one to check writing function in scripts/SUS/InMatCalc/testingInMat.py . We have created backup text file for current settings in backupMC1InMat.txt .
• Uploaded the new input matrix in normalized form. To normalize, we first made each row vector unit vector and then multiplied by the norm of current input matrix's row vectors (see scripts/SUS/InMatCalc/normalizeNewInputMat.py)
• Switched ON the PSL shutter (C1:PSL-PSL_ShutterRqst)
• Switched ON IMC autolocker (C1:IOO-MC_LOCK_ENABLE)
• Locked was caught immediately. The wavefront sensor of MC1 shows usual movement, nothing crazy.
• So the new input matrix is digestable by the system, but what's the efficacy of it?

< Two inspection people taking pictures of ceiling and portable AC unit passed. They rang the doorbell but someone else let them in. They walked out the back door.>

Testing how good the input matrix for MC1 is:

• We loaded the input matrix butterfly row in C1:SUS-MC1_LOCKIN_INMATRX_1_4 to 8. This matrix is multiplied by C1:SUS-MC1_UL_SEN_IN and so on channels before the calibration to um and application of toher filters.
• We tried to look around on how to load the same filter banks on the signal chain of LOCKIN1 of MC1 but couldn't, so we just manually added gain value of 0.09 in this chain to simulate the calibration factor at the very least.
• We started the oscillator on LOCKIN 1 on MC1 with amplitude 1 and frequency 6 Hz.
• We added butterfly mode actuation output column (UL:1, UR:-1, LL:-1, LR:1), nothing happened to the lock of probably because of low amplitude we put in.
• Now, we plot the ASD of channels like C1:SUS-MC1_SUSPOS_IN1 (for POS, PIT, YAW, SIDE) to see if we see a corresponding peak there. No we don't. See attachment 1.

Restoring the system:

• Added 0 to the LOCKIN1 column in MC1 output matrix.
• Made LOCK1 oscillator 0 Amplitude, 0 Hz.
• Changed back gain on signal chain of LOCKIN1 on MC1.
• Added 0 to C1:SUS-MC1_LOCKIN_INMATRX_1_4 to 8.
• Switched off the PSL shutter (C1:PSL-PSL_ShutterRqst)
• Switched off IMC autolocker (C1:IOO-MC_LOCK_ENABLE)
• Wrote back the old matrix by scripts/SUS/InMatCalc/testingInMat3.py which used the backup we created.
• Switched ON the PSL shutter (C1:PSL-PSL_ShutterRqst)
• Switched ON IMC autolocker (C1:IOO-MC_LOCK_ENABLE)

 This is how it was envisioned. The video camera was in nobodies mind to look through the 40 mm  diameter hole than.

 Rana is proposing 50 mm hole in the baffle plate that is attached to the tower.  Atm1

Atm2 is showing the back side where the solid line is 40 mm

 Green welding glass  is used in these Koji designed dumps (D1102375)

We have 10 pieces of hexagonal  dumps for 5.5" high beam They require 1 5/8" space.  Atm1 

Atm2, Large V traps are 3" tall only, 5 pieces

Atm3, Diamond shapes come with 2" and 1" square green glass ( after Koji's correction I removed the not needed glass ) D1102445 and D1102442

Baked green glass pieces in stock: 30 pieces of 2" x 2" ,---  30 pieces of 1" x 1",David 4-17-2014

Baked diamond holders in stock: 10 pieces of 2" and 10 pieces of 1"David 4-17-2014

PEEK shims 2" and  1"

Baked green glass pieces blank:  4 pieces of 7" x 9"

Baked green glass pieces with 40 mm hole on 7" x 9" for SUS tower:  7 pieces.

NOTE: in December 2012 we talked about 50 mm aperture need. What diameter is the right one  today? 51 mm aperture plates are cut 4-10-2014

Zeroth order IMC ringdown setup

Following Gautam's IMC ringdown setup, I took the REFL PD form the PMC ringdown experiment and installed it in the IMC REFL path blocking WFS2 (Attachment 1).

I also ran a BNC cable from the transmission PD that Gautam installed on the IMC table to the vertex where the signals are measured on the scope. 

I offloaded the WFS servo output values onto the MC alignment (using the WFS servo relief script) so that its dc values would be correct when the servo is off.

Unfortunately, it seems like the script severely misaligned the MC mirrors at some point when the MC got unlocked. We should fix the script such that it stops when the offloading is complete.

We got the MC realigned but left it in a state where it is not locking easily.

AUX PDH Loop update

I used D1400293 to get the latest logged details about the universal PDH box used to lock the green laser at X end. The uPDH_X_boost.fil file present there was used to obtain the control model for this box. See attachment one for the code used. Since there is a variable gain stage in the box, I tuned the gain of the filter model F_AUX in ALS_controls.yml to get the maximum phase margin in the PDH lock of the green laser. Unity gain frequency of 8.3 kHz can be achieved in this loop and as Gautam pointed out earlier, it can't be increased much further without changes in the box.

ALS Noise Budget update

The ALS control model remains stable with a reduction in total estimate noise because of the above update. There are few things to change though:

• This model is for a single arm locking where the beatnote signal between green laser and frequency doubled main laser is fed back to ETM at X end. Currently, Gautam is using a different scheme to lock where the feedback is sent to PSL-MC loop and the beat is taken between IR signals.
• In the LSC controls, I couldn't find a place where the digital ALS filter I have been optimizing and Kiwamu used, was placed. From what I gathered, after demodulation of beat note signal, a digital PLL is employed and the error signal is few to the Servo Filters directly. I might be missing some script which specifically switches on a particular set of filter modules in the XARM/YARM path when arms are locked through ALS.
• Another straight forward job for me is to verify the PSL-MC loop parameters with he TTFSS used. I'll do this next.

Gautam will soon follow up with detailed analysis, but here is a brief summary of some of our activities and findings.

• Two Marconis were beat together in various ways, we figured the noise added by turning on external modulation didn't make us happy. 
• I locked the AUX X laser to the PSL via PZT. I'm more likely to believe we're seeing real broadband laser noise in this configuration; locking the the PSL laser to the IMC brought the noise down in a reasonable way. The PLL bandwidth was a smidge over 100k.
• We saw a factor ~6 increase in noise when changing the diode current from 1.8 to 1.96A. We'll be following this up at more temperatures and currents soon. 
• Gautam will verify the AUX X laser PZT calibration tomorrow, and post calibrated spectra of this increase. 

Please note that there is a long BNC cable still laid out from the IOO rack area to the X end table; watch your step!

I took spectra (attached) with the same actuation range (3.2 MHz/V) for the AUX X+PSL and AUX Y+PSL combinations (PSL shutter closed) just to keep things consistent. It looks like there is hardly any difference between the two combinations - could the apparent factor of 3 worse performance of the X end laser have been due to different actuation ranges on the Marconi? 

I've not managed to take a spectrum for the proposed replacement Lightwave laser on the PSL table, though with Eric's help, I've managed to find the beatnote (at a temperature of 53.0195 degrees). I had to do some minor alignment tweaking for this purpose on the PSL table - the only optics I touched were the ones in the pink beam path in attachments 1 and 2 in this elog (the setup used to make the measurement is also qualitatively similar to attachment 3 in the same elog, except for the fact that we are feeding back to the Marconi and not the laser - a detailed sketch with specific components used will be put up later). I'll try and measure the frequency noise of this laser as well over the weekend and put up some spectra. 

With regards to possibly switching out the Lightwave on the PSL table for the (faulty?) Innolight at the X end, I've verified the following:

• The beam-height from the Lightwave on the mount it is currently sitting on is the same as that from the Innolight on the X end table.
• There is sufficient space on the X end table to house the Lightwave laser+mount

It remains to characterize the beam coming out from the Lightwave laser and do a mode matching calculation to see if we can use the same optics currently in place (with slight rearrangement) to realize a satisfactory mode-matching solution - I've obtained a beam profiler to do this from Liyuan and have the software setup, but have yet to do the beam scan - the plan is to do this on the SP table, but we've put off moving the Lightwave laser off the PSL table until we (i) establish conclusively that the X end laser is malfunctioning and (ii) check the frequency nosie of the Lightwave relative to the Aux lasers currently at the ends. 

The area around the Marconi is in a little disarray at the moment with a bunch of cables, SR560s, analyzers etc - I didn't want to disconnect the measurement setup till we're done with it. I have however turned both IR beat PDs on the PSL table off, and have reconnected the Marconi output to the Frequency Generation Unit and have set the carrier back to 11.066209MHz, +13dBm. 

EDIT 01/12/2016 6PM: I've updated the plots of the in-loop spectra such that they are calibrated throughout the entire domain now. I did so by inferring the closed-loop transfer function (G/(1-G)) from the measured open-loop transfer function (G), and then fitting the inferred TF using vectfit4 (2 poles). The spectra were calibrated by multiplying the measured spectra by the magnitude of the fitted analytic TF at the frequency of interest.

EricQ brought back one of the Marconis that was borrowed by the Cryo lab to the 40m today (it is a 2023B - the Marconi used for all previous measurements in this thread was 2023A). Koji had suggested investigating the frequency noise injected into the PLL by the Marconi, and I spent some time investigating this today. We tried to mimic the measurement setup used for the earlier measurements as closely as possible. One Marconi was used as a signal source, the other as the LO for the PLL loop. All measurements were done with the carrier on the signal Marconi set to 310MHz (since all our previous measurements were done around this value). We synced the two Marconis by means of the "Frequency Standard" BNC connector on the rear panel (having selected the appropriate In/Out configurations digitally first). Two combinations were investigated - with either Marconi as LO and signal source. For each combination, I adjusted the FM gain on the Marconi (D in the plot legends) and the overall control gain on the SR560 (G in the plot legends) such that their product remained approximately constant. I measured the PLL OLG at each pair to make sure the loop shape was the same throughout all trials. Here are the descriptions of the attached plots:

Attachment #1: 2023A as LO, 2023B as source, measured OLGs

Measured OLG for the various combinations of FM gain and SR560 gain tested. The UGF is approximately 30kHz for all combinations - the exceptions being D 1.6MHz, G=1e4 and D=3.2MHz, G=1e4. I took the latter two measurements just because these end up being the limiting values of D for different carrier frequencies on the Marconi.

Attachment #2: 2023A as LO, 2023B as source, measured spectra of control signal (uncalibrated above 30kHz)

I took the spectra down to 2Hz, in two ranges, and these are the stitched versions. 

Attachment #3: 2023B as LO, 2023A as source, measured OLGs

Attachment #4: 2023B as LO, 2023A as source, measured spectra of control signal (uncalibrated above 30kHz)

So it appears that there is some difference between the two Marconis? Also, if the frequency noise ASD-frequency product is 10^4 for a healthy NPRO, these plots suggest that we should perhaps operate at a lower value of D than the 3.2MHz/V we have been using thus far? 

As a quick trial, I also took quick spectra of the PLL control signals for the PSL+Aux X and PSL+Aux Y beat signals, with the 2023B as the LO (Attachment #5). The other difference is that I have plotted the spectrum down to 1 Hz (they are uncalibrated above 30Hz). The PSL+Y combination actually looks like what I would expect for an NPRO (for example, see page 2 of the datasheet of the Innolight Mephisto) particularly at lower frequencies - not sure what to make of the PSL+X combination. Also, I noticed that the amplitude of the PSL+Y beatnote was going through some large-amplitude (beat-note fluctuates between -8dBm and -20dBm) but low frequency (period ~10mins) oscillations. This has been observed before, not sure why its happening though. 

More investigations to be done later tonight.

EDITS 15Jan:

1. Schematic of test setup added (Attachment #5). Note that the UGF measurements were made with the LPF and gain on the 'wrong' SR560, in a way defeating the purpose of having 2 SR560s in the setup. I only realised this after taking the measuements. But having done the loop algebra, I believe we can extract the necessary information, which is what has been done in subsequent plots...
2. Koji pointed out that UGFs of ~100kHz was probably too high - this is when I took a closer look at the setup and realised the remarks made above in point 1. I realised we were in fact measuring the 'Process' open-loop TF. We can recover the loop TF by measuring the controller TF (which I did, see Attachment #3). The UGF for the PSL+X PLL loop is ~7.5kHz while that for PSL+Y is ~22kHz (both with a 1Hz LP on the SR560 and gain of x200).
3. During the above investigations, I found that the measured TF for a 1Hz LP on the SR560 is weird - there seems to be a zero around 5kHz which gives some phase lead where one would expect a uniformly decaying gain and phase to be -90 degrees. Eric and I confirmed this behavioud on another SR560. Low-pass at 10kHz and high-pass at 1kHz seem to work fine. I will investigate this further when I get the time. Anyhow I don't think this affects anything as long as we measure the correct OLTF. It is still not clear to me why we even need this to lock the PLL...
4. All the spectra (Attachment #4 and #5) are now calibrated taking into account the loop TF. I've added another panel with the spectra in V/rtHz as measured on the SR785, along with the SR560 output noise. I don't think any of the conclusions below are affected by these edits.

Summary:

I took several measurements today using the revised PLL scheme of using the Marconi just as an LO, and actuating on the Laser PZT to keep the PLL locked (I will put up a sketch soon). On the evidence of the attached plots (spectra of PLL control signal), I guess we can conclude the following:

1. The AUX X laser's frequency noise performance is consistent with the levels expected from 'typical' NPRO numbers (and the datasheet), and is more or less consistent across different diode currents/crystal temperatures (? see below...).
2. The diode current should be set to something less than 2.00 A
3. Qualitatively, there is a difference in the shape of the spectra between the PSL+X and PSL+Y combinations above a couple of kHz. I don't know why we see this.

Attachment #2: Measured OLG of PLL for the PSL+X and PSL+Y combinations. The UGF in both cases looks to be above 100 kHz, so I didn't do any calibration for the spectra attached. The gain on the SR560 was set to 200 for all measurements.

Attachment #3: Measured spectra of PLL control signal for various diode currents, with one reading from the PSL+Y combination plotted for comparison. When we took some data last night, Eric noted that there was a factor of ~6 increase in the overall frequency spectrum level at higher currents, I will update the plots with last night's data as well shortly. I found it hardest to keep the PLL locked at a diode current of 2.00 A across all measurements.

Attachment #4: Measured spectra of PLL control signal at two different crystal temperatures. There does not seem to be any significant dependance on temperature, although I did only do the measurement at two temperatures.

Attachment #4 Attachment #1: All the data used to make these plots (plus some that have yet to be added to the plots, I will update them).

Misc notes:

• All measurements taken with two free-running lasers (PSL shutter closed)
• The SR560 noise was measured with the input on the SR560 set to ground. 
• In order to go from V/rtHz to Hz/rtHz on the plots, I used 1MHz/V for the X-end laser (which I verified by a quick measurement today to be approximately correct) and 4.6 MHz/V for the Y-end laser, based on an earlier measurement. 
• I re-routed the long BNC cable to the Y-end, have yet to remove it. The BNC from the PDH setup at the X-end has been re-attached to the X-end NPRO.

Unrelated to this work:

When I came in this afternoon, I noticed that the PMC was unlocked. The usual procedure of turning the servo gain to -10dB and playing around with the DC output adjust slider on the MEDM screen did not work. Eric toggled a few buttons on the MEDM screen after which we were able to relock the PMC using the DC output adjust slider.

Summary:

Retraining the MCL filters resulted in a slight improvement in the performance. Compared to no FF, the RMS in the 0.5-5 Hz range is reduced by approximately a factor of 3. 

Details:

Attachment #1 shows my re-measurement of the MC2 position drive to MCL transfer function.

• The measurement was made using DTT swept sine, with the amplitude enveloped appropriately to avoid knocking the IMC out of lock.
• Coherence was >0.97 for all datapoints.
• Fitting was done using Lee's IIRrational, with the weighting being the coherence. I think there are some features of the fitting I don't fully understand, but I wanted to try and do everything in python and for this simple fit, it came out nicely I think. 

Attachment #2 shows the IIR fits to the FIR filters calculated here. 

• Again, IIRrational was used. 
• In the frequency band where subtraction is possible, the fit is good.
• But there is definitely room for improvement in the way this is done, for now, I did quite a bit "by eye" and tweaked the order of the filter and the minimum number of excess poles relative to zeros to get the AC coupling, but it'd be nice to make all of this iterative and quantitative (e.g. by minimizing a cost function).
• One nice feature of IIRrational is that it directly gives me a formatted string I can paste into foton. The order of these fits were 22, so I split them into two 19+3 order filters to be compatible with the realtime system before loading the coefficients (the overall gain was allocated to a single filter arbitrarily, with the other filter in the pair set to have unity gain in the zpk representation).

Attachment #3 shows several MCL spectra.

• Blue trace is the unsubtracted test dataset.
• Red is the performance of the calculated FIR filter, but the filtering is done offline.
• Gold is the performance of the IIR fit to the FIR filter, as shown in Attachment #2, applied offline to the test dataset.
• Green is the calculated ASD of MCL from a ~1 hour stretch from earlier tonight, when I left the feedforward loop on. So this is an actual measurement of the online performacne of the filter.
• Grey is the performance of the old filter loaded in the CDS system - the filtering is done using scipy, and the sos coefficients from the C1OAF.txt file.

Conclusions + next steps

1. Retraining the filters has resulted in a slight improvement, especially at ~3 Hz.
2. More tests need to be done to confirm that noise isn't being reinjected in the frequency bands where subtraction isn't possible (e.g. using arm cavities as OOL sensors).
3. The online filter isn't quite as good as what we would expect from calculations (green trace is noisier than gold). Need to think about why this is.
4. Why can't we get more subtraction at 1 Hz?
5. Now that I have the infrastructure ready, I will attempt to revive the PRC angular FF loops, which was the whole point of this exercise. 

For all the loops where we drive the NPRO PZT, there is some notch/resonance feature due to the PZT mechanical resonance. In the IMC loop this limits the PZT/EOM crossove to be less than 25 kHz. I don't have a model for this, btu it should be included.

If you hunt through the elogs, people have measured the TF of ALS NPRO PZT to phase/frequency. Probably there's also a measured ALS PDH loop somewhere that you could use to verify your model.

1) do a comparison with the whtiening before the ADC on/off. This will tell us if it is pickup before the whtiening filter or not.

2) If there are ground loops made by 44 MHz setup, we want to draw a simple diagram which includes which sides are grounded and which have transformers. How about make a drawing to bring to the group meeting tomorrow? IN the lab we have these coaxial BALUNs for making a 1:1 transformer coupling.

3) Another source of 60 Hz is the unintentional demodulation of spikes made by the Sorensen switching supplies: they produce spikes all the way up to 100 MHz, so if they land near 44 MHz, you may get some 60 Hz on the demodulation. You should be able to see this with a dipole antenna or a hoop antenna.

 The south end crane has one more flaw. The wall cantilever is imbalanced: meaning it wants to rotate south ward, because its axis is off.

This effects the rope winding on the drum as it is shown on Atm2

Atm1 is showing Jay Swar of KoneCrane and the two 1250 lbs load that was used for the test. Overloading the crane at 125% is general practice at load testing.

It was good to see that the load brakes were working well at 2500 lbs. Finally we found a good service company! and thanks for Rana and Alberto

for coming in on Saturday.

 Jeff Stinson, technician of KoneCrane inspected the south end crane hoist gear box. This was the one that was really low on oil. The full condition require

~ 950cc of EPX-7 (50-70W) high viscosity gear oil. The remaining 120 cc oil was drained and the gear box cover was removed. See Atm 1

He found the gear box, load brake and gearing in good condition. The slow periodic sound of the drive was explained by the split bearings at Atm 3

The Vertex and the east end crane gear boxes needed only 60 cc oil to be added to each Atm 4 and their drives were tested.

Conclusion: all 3 gear boxes and drives are in good working condition.

Tomorrow's plan: load test at 1 ton and correct-check  3 phase wiring.

 Atm1, service report: load test were performed at max horizontal reach with 1998 lbs ( American Ton is 2000 lbs)

          Vertical drives and brakes worked well. The 5 minutes sagging test showed less than 1 mm movement .

          The wiring is correct. Earlier hypothesis regarding the wiring ignored the mechanical brake action.

Our cranes are certified now. Operator training and SOP is in the work.

Vertex Folding I -beam will get latch-lock and the south end I-beam will be leveled.

Atm2, south end

Atm3, east end

Atm4, folding crane at ITMX at 14 ft horizontal reach

Just to show how bad 60 Hz noise is, I compared FPMI displacement noise with pre-BH44 era (measured on Jan 13, 40m/17400).
Blue curve in Attachment #1 is the sensitivity with FPMI locked with RF in pre-BH44 era, and pink curves are that measured today (C1:CAL channels are currently unavailable due to 0x2000 appeared after running restatAllModels.sh).
60 Hz + harmonics pedestals are apparent today, but was not there on Jan 13. Today, DARM could be handed over to AS55_Q from POX11-POY11, but CARM could not be handed over to REFL55_I from POX11+POY11 (this was possible last night).
Attachment #2 shows FPMI error signals when electronic FPMI is locked. Too much 60 Hz, especially in REFL55_I_ERR and AS55_I_ERR (note that REFL55_Q is used for MICH lock, but AS55_Q is not in-loop yet when this screenshot was taken.)

Next:
  - Fix c1cal 0x2000 issue
  - Fix REFL55 loose RF output
  - Disconnect cables in BH44 to open possible ground loops made during BH44 installation (especially 44 MHz generation part??).

yes, its fine to use this with a level 3 or level 7 mixer; let's see some PM transfer functions !

 What does OAF stand for? The entry doesn't say that. Also the acronym is not in the abbreviation page of the wiki.

Can anyone please explain that?

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.

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.

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.

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.

 

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.

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.

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.

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).   

Acromag is talking now, after few changes to the original EPICS configuration and cross compile configuration. Modbus config files also were changed and compiled again to run it on linux-arm architecture. I have made use of pyModbus for the final work and I am planning to use the same for grabbing channels. Though I am unable to grab channel data right now, I am able to communicate to it over ethernet and send and receive data. 
 

Aidan has described the physical connections and initial setup here :  https://nodus.ligo.caltech.edu:30889/ATFWiki/doku.php?id=main:resources:computing:acromag#recovering_from_a_terminal_power_communication_outage  .

Since I used a Raspberry Pi(domenica.martian) for communicating to Acromag(acroey.martian) card, I had to recompile everything for linux-arm architecture. 

For EPICS installation, download the EPICS base from http://www.aps.anl.gov/epics/download/base/baseR3.14.12.3.tar.gz . Installing dependencies, build, install epics at /usr/local/epics. By downloading modbusApp source from https://llocds.ligo-la.caltech.edu/daq/software/source/epics-3.14.12.2_long-source.tar.gz  , build the modbusApp for linux-arm architecture in modules/modbus directory inside epics base.

Put all the files mentioned by Aidan and run a tmux session to grab channels.

Also, pyModbus can be used to read the channels. I'll put the physical connections schematic shortly.

I took off the silicon rubber heaters which were used by a SURF last year for heating the enclosure. The heater data sheet has mentioned the power dentsities, but I doubted the values. So I wanted to measure the actual power density by these heaters. I think the rubber heaters are broken somewhere within, the surface is not heated evenly. Although I don't have a good quantative reason to use, I was thinking to use a thermoelectric cooling module for the enclosure. 

From the data I collected few days back, I am trying to obtain a transfer function of temperature inside the enclosure to that of outside. My aim is to measure the pole frequency of temperature fluctuations inside the enclosure relative to the outside fluctuations.

I have measured the transfer function of temperature fluctuations inside the enclosure to that of the temperature fluctuations outside. The transfer function has been estimated by using 'tfestimate' which is library function in Matlab and which estimates the transfer function based on Welch's method. The attached plots shows the transfer function of the temperature inside the enclosure to that of outside temperature.

fig1.pdf

fig2.pdf

In order to determine a relation between temperature inside the enclosure to that of the outside temperature, I have calculated the mean squared coherence.  I have used Matlab's 'mscohere' library function which uses Welch's method to calculate the coherence. Attached plot shows the coherence between the temperature across the enclosure.

fig3.pdf

Also, I have attached the matlab script which I used for generating these plots.

script21jul2016.m

I have made the changes as suggested by Gautam.

Please find the new attached plots and the new script.

I tried to recompile the modbusApp binary for linux-arm acrhitecture since I suspected someting wrong with it. But still the problem persists; I can connect to acromag but cannot access the channels. I have also reconfigured new acromag bus works terminal XT 1221-000 and I want to test if I could access its channels. My target is to complete this acromag setup work before sunday morning so that I can focus towards having some useful results for my presentation.
 

There were many unknown and unsolved problems with using modbusApp for linux-arm architecture. So I tried to install the necessary files to setup Acromag Busworks card 1221-000 on Zita(192.168.113.217), which is a linux-x86_64 machine on the martian network. After installing a few dependencies and seting up few symbolic links for some libraries, everything is successfully configured. Initially I was unable to run myiocconfig.cmd file(as mentioned by Aiden on ATF wiki page) due to a undefined macro error for envset. Later I found that this error might be due to THIS bug in epics base. So, I removed the first four lines of that given code and directly referenced the .db file's location and it worked.

Now, I am facing another issue while running this file but on different line. Random symbols are returned on the last second line of the file each time I run it. I have attached the screenshots of those errors. I tried changing the encoding of the file several times but still it is showing the same error.

Lydia helped me to troubleshoot the Accromag connection problems which I was facing previously.  If power goes off/turned off manually, the ethernet cable has to be pulled out and put back again until only a non-blinking green light is observed. I was foolish enough that I did not use secure power connections. About the random symbol, a code block was not closed in the other supporting file which was being called in the main program. There are still some port errors and register errors, which I would work on later tonight.

I've taken the FSS frequency generation box out of the 1Y1 rack. It's sitting on one of the electronics benches. I'm measuring its phase noise.

I measured the scatter from the eLIGO beam dumps as best I could. The experiment setup is shown in the attached diagram. 

After familiarizing myself with the equipment in the morning I noticed three issues with the setup

1 - around the minimum scatter the back scatter from the beam dump is very susceptible to the incident angle (makes sense since the Si plate inside the beam dump at Brewster's angle when there is minimum scatter).

2 - The mirrored plug (Part 20 in D0900095) which is suppose to be used for alignment is not very effective. It moves around too much in its hole in the front face of the beam dump. Just by touching it I could make the reflected beam jump around by about 0.1 radians.

- I think to align these properly we'll have to partly assemble the dumps. If we leave off the front plate of the horn then we can measure the reflection off the Si. If we measure this with a power meter then alignment becomes a simple matter of rotating until this reflection is minimized.

3. - For this measurement the incident beam was a small (~ 1mm diameter) central beam with a small amount of spray of laser light beyond that central region. This spray was hitting the aluminium front face of the beam dump and was scattering back to the photodiode. This was clearly the limiting factor in the measurement. Most of this light was spread horizontally so I placed a couple of pieces of black glass on either side of the aperture, just blocking the edges a little. This reduce the background reading at the minimum scatter from 17.0uV to around 4.5uV with still a little bit of light hitting the top and bottom of beam dump face.

The incident power on the beam dump fluctuated a little but was in the range 20.5 to 22mW. The response of the PD is approximately 0.2 A/W and the transimpedance is 7.5E4 V/A.

The SR830 Sensitivity was set to 1x1 mV.

It was difficult to measure the actual angle of incidence. The dump pivoted about a point directly under the input aperture at the front. By measuring the displacement of a point on the back of the dump as I rotated it and knowing the distance between this point and the pivot point I was able to make a reasonably accurate measurement of a range of angles about the minimum.

The measured scatter (in V measured directly by the PD and as a fraction of the incident power) is shown in the attached plots.

I think I can do a better job cleaning up the incident beam - so these numbers only represent an upper limit on the scatter.

attachment 1: beam dump assembly

attachment 2: experimental layout

attachment 3: scatter measurement

attachment 4: BRDF - (scatter divided by the solid angle = 1.1 m steradians)

attachment 5: (slightly blurred )photo of dump - overhead view 

See Adhikari eLOG entry: http://nodus.ligo.caltech.edu:8080/AdhikariLab/194

 The elog crashed when I was uploading a photo just now. I logged into nodus and restarted it.

The beams from the Innolight and Lightwave NPROs were both incident on a 1GHZ New Focus PD. Mott and I swept the temperature of the Lightwave and tracked the change in frequency of the beatnote between the two. The Innolight temperature was set to 39.61C although the actual temperature was reported to be 39.62C.

Freq. vs temperature is plotted below in the attached PDF. The slope is 2.8GHz/K.

The data is in the attached MATLAB file.

There is a clearly a difference in the divergence angle of the x and y beams - maybe 10-20%. Since the measurements are outside the Rayleigh range and approximately in the linear regime, the slope of the divergence in this plot should be inversely proportional to the waists - meaning the x- and y- waist sizes should differ by about 10-20%. You should check your fitting program for the waist.

Jenne, Koji and I opened up the package from Raicol and examined the crystals under the microscope. The results were mixed and are summarized below. There are quite a few scratches and there is residue on some of the polished sides. There is a large chip in one and there appear to be gaps or bands in the AR coatings on the sides.

There are two albums on Picassa

1. The package is opened ...

2. The crystals under the microscope.

 Here is Crystal 724 polished side 2 with all photos along the length stitched together

 Here's a photo of the set-up used. The beam profile is measured relative to the f=-100mm lens.