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ID Date Author Type Category Subject
  13002   Mon May 22 10:53:02 2017 DhruvaUpdateOptical LeversBeam Profiling Results

 

Quote:

Andrew and I set up the razor blade beam profiling experiment for He-Ne lasers on the "SP" table.  Once I receive the laser safety training, I will make power measurements and fit it to an erfc curve from which I will calculate the gaussian profile of the beam. I'm attaching some pictures of the setup. 

Least count of the micrometer - 2 microns 

Laser  : Lumentum 22037130:1103P

Photodetector : Thor Labs PDA100A

I had measured the y-profile of the beam of Friday at 5 axial locations and fit them to an erfc function using the lsqcurvefit function of MATLAB. 

The results were as follows - 

z(cm)    w (in)

4          0.0131

10        0.0132

15        0.0137

20       0.0139

25        0.0147

I left w in inches in the intensity plots as MATLAB gave more accurate fits for those values.

I converted these to S.I while making the spot-size vs z plot and the corresponding values in microns were 

332.74, 335.28, 347.98, 353.06, 373.38.

On fitting these values to the formula for the spot size of a Gaussian beam, the beam waist came out to be 330.54 microns and the location of the beam waist was at z=-2cm, where z=0 marks the head of the laser. 

 

TO-DO : Measure the spot size of the beam at more axial points to obtain a better fit. 

              Measure the x-profile of the beam. 

              Analyse the error in the spot sizes and corresponding error in the beam waist. 

 

 

Attachment 1: spot_size_.pdf
spot_size_.pdf
Attachment 2: z_25.pdf
z_25.pdf
Attachment 3: z_20.pdf
z_20.pdf
Attachment 4: z_15.pdf
z_15.pdf
Attachment 5: z_10.pdf
z_10.pdf
Attachment 6: z_4.pdf
z_4.pdf
  13000   Mon May 22 10:15:14 2017 jigyasaSummarytelescope designLens tubes and object distances

Since the f numbers of the lenses in the proposed design with biconvex lenses are a little less than 5 and the conjugate ratio(that is the ratio of object to image distance) is greater than 5, I explored the use of plano convex lenses, but with the same focal lengths, the accessible u-v range is restricted with the planoconvex rather than biconvex lenses.
On Friday, I had a discussion with Gautam and Steve about the hardware that is the cylindrical enclosures for the camera and the telescope and we examined two such aluminum cylindrical enclosures. One of them was the one being currently employed for the cameras. The dimensions were measured and the length was found to be 8’’ and an outer diameter of 26 cm within an error of 0.5 cm.
The other enclosure was longer with a length of 52 cm(±0.5 cm), outer diameter of 10”(±0.1”) and an inner diameter of 23.7cm(±0.1cm). Pictures of these enclosures are attached.
Both of these enclosures have internal optical rail to mount the camera and the telescope system. Depending on the weight of the telescope system(that includes the weight of the slotted lens tubes, the lenses), it might be more efficient to clamp the telescope system itself on the rails with the low weight camera mounted on the lens tube.
I also went around to get an idea of distance of the GigE from the test masses. This was just a step to verify if the object distances were really in the ranges being taken into consideration, that is between 1500 and 2500 mm. I also tried to cross check the measurements with the CAD drawing of the 40m. However, as I have been informed, the distances in the CAD version are not updated.

The distances from the optic to the CCD detector would range from around 75.1 cm for MC2, 94.01 cm for ITMX, 97.21 cm for ETMX, 117.19 cm for ITMY and 88.463 cm for ETMY. The illuminator for the ETMY was disconnected, so Gautam helped me access the manual lamp control to enable me to take measurements.
The values for ETMX, MC2 and ITMY are subject to an error of ±1’’. Due to a lot of obstructions, the values for ETMY and ITMX may be subject to a lot more error. Even so, these distances are clearly less than 2 meters, prompting me to run the simulations again and verify that the chosen combination is still useful.

As for the slotted lens tubes to mount the 2” lenses, the following options are available on the Thorlabs catalog. CVI and Edmunds do not seem to offer much of the stackable lens tubes.

SM2L30C is a lens tube onto which the optic can be mounted without the need of a spanner wrench. It also has a length of 3”. However, it has a rotatable slip shield which can be rotated open as and when the access to optic is required. However, there might be a slight compromise with rigidity here.

SM2L30 is a lens tube with internal thread depth of 3”, the optic can be mounted using spanner wrench and a retainer ring. The optic cannot be accessed from both ends of the tube here.
SM2M30 is a lens tube with no external threads, therefore lens tube couplers would be required to stack the tubes. The optic is accessible from both ends here though.

Considering the merits and demerits of all these available options, the use of SM2L30 might be considered as it provides a quick and efficient way of stacking multiple lens tubes. As for accessing the optic from both sides, using multiple tubes helps overcome the problem and still ensures that we are able to access a number of separation distances as per requirement.
Thorlabs also offers an internal C to external SM2 adapter so that the lens tube could be fixed onto the C mount of the camera. 

I would be examining the use of 1" diameter lenses for the eyepiece as suggested by Rana, as that might give us more flexibility. 

Attachment 1: Pictures1.pdf
Pictures1.pdf Pictures1.pdf Pictures1.pdf Pictures1.pdf
  12999   Fri May 19 19:18:53 2017 KaustubhSummaryGeneralTesting of the new Photo Detectors ET-3010 and ET-3040

Motivation:

I got some hands-on-experience on using RF photodetectors and the Network Analyzer from Koji. There were newly purchased RF photodetectors from Electro-Optics Technology, Inc.. These were InGaAs Photodetectors with model no.: 120-10050-0001(ET-3010) and 120-10056-0001(ET-3040). The User Guide for the two detectors can be found here. This is the first time we bought the ET-3010 model PD for the 40m lab. It has an operation bandwith >1.5GHz(not tested yet), much higher than other PDs of its kind. This can be used for detecting the output as we 'sweep' the laser frequency for getting data on the optical cavities and the resonating modes inside the cavity. We just tested out the ET-3040 model today but will test out the ET-3010 next week.

Tools and Machines Used:

We worked on the optical bench right in front of the main entrance to the lab. We put the cables, power chords, etc. to their respective places. We used screws, poles, T's, I's, multimeter, Network/Spectrum Analyzer(along with the moving table), a lab computer, Oscilloscope, power supply and the aforementioned PDs for our testing. We took these items from the stack of tools at the Y-arm and the boxes of various different labelled palced near the X-arm. We moved the Network Analyzer(along with the bench) from near the Y-arm to our workplace.

Procedure:

I will include a rough schematic of the setup later.

We alligned the reference PD(High Speed Photoreceiver model 1611) and the test PD(ET-3040 in this case) to get optimal power output. We had set the pump current for the laser at 19.5mA which produced a power of 1.00mW at the output of the fiber couple. At the reference detector the measured voltage was about 1.8V and at the DUT it was about 15mV. The DC transimpedance for the reference detector is 10kOhm and its responsivity to 1064 nm is around 0.75A/W. Using this we calculate the power at the reference detector to be 0.24mW. The DC transimpedance for the DUT is 50Ohm and the responsivity of about 0.9A/W. This amounts to a power of about 0.33mW. After measuring the DC voltages, we connected the laser input to the Network Analyzer and gave in an RF signal with -10dBm and frequency modulation from 100 kHz to 500 MHz. The RF output from the Analyzer is coupled to the Reference Channel(CHR) of the analyzer via a 20dB directional coupler. The AC output of the reference detector is given at Channel A(CHA) and the output from the DUT is given to Channel B(CHB). We got plots of the ratios between the reference detector, DUT and the coupled refernce for the Transfer Function and the Phase. We found that the cut-off frequency for the ET3040 model was at arounf 55 MHz(stated as >50MHz in the data sheet). We have stored the data using the lab PC in the directory .../scripts/general/netgpibdata/data.

Result:

The bandwidth of the ET-3040 PD is as stated in the data sheet, >50 MHz.

Precaution:

These PDs have an internal power supply of 3V for ET-3040 and 6V for ET-3010. Do not leave these connected to any instruments after the experiments have been performed or else the batteries will get drained if there is any photocurrent on the PDs.

To Do:

A similar procedure has to be followed in order to test the ET-3010 PD. I will be doing this tentatively on Monday.

Attachment 1: IMG_20170519_173247922.jpg
IMG_20170519_173247922.jpg
Attachment 2: IMG_20170519_173253252.jpg
IMG_20170519_173253252.jpg
Attachment 3: IMG_20170519_173300174.jpg
IMG_20170519_173300174.jpg
Attachment 4: PD_test_setup.png
PD_test_setup.png
  12998   Thu May 18 15:20:29 2017 jigyasaSummarytelescope designTelescope Design for the Gig-E cameras

With the objective of designing a telescope system for the Gig-E, a system of two lenses is implemented. A rough schematic of the telescope system is attached. Variables in the system include the focal lengths of the two spherical lenses(f1, f2), distance between the lenses(t), distance between the test mass and the lens combination(u), distance between the other lens and the sensor(v). Also the size of the object to be desired ranges from 3’’ which is the size of the test mass to 1’’ which is approximately focusing on the beam spot implying that the required magnification ranges from 0.06089 to 0.1826 (since the sensor image circle size if ¼”)
The lenses are selected to be 2” in diameter so as to ensure sufficient collected power.

Going through the focal lengths available, namely 50, 100, 150, 200, 250 mm, and noting that the object distance would be within the ranges of 1500 to 2500 mm, plots of various accessible u and v for different values of t were obtained. This optimization was done to ensure the proper selection of the lenses. Additionally, a sensitivity analysis was performed and plots depicting the dependence of magnification on the precision limiting measurements of u (1 mm) and t (5 mm) were obtained. (These were scatter plots quantifying the deviation from the desired magnification ranges). The plots depict the error term induced on the magnification if there was an error in measuring the distance between the lenses as 5mm and if the precision in measuring the object to lens distance by 1mm.

The telescope design might be limited by spherical aberrations and coma, which might be resolved by either using aspherical lenses or by increasing the f-number (typically with an f number around 5 or 6). The use of aspherical lenses particularly parabolic lenses was considered, however this was found to be quite an expensive route. 

Analyzing the plots and taking into consideration the restrictions of the slotted lens tubes, the precision in measurement of the distances, a 150 mm- 250mm focal length solution is proposed. With a diameter of 2”, the f number is computed to be 2.95 and 4.92. With this combination and the object distances lying between 1500 to 2500 mm, the image distance to the sensor varies between 51 to 100mm. So a slotted lens tube controlling the distance between the lenses would be required.

I also considered a combination of focal lengths 250mm and 250mm, as then both of the lenses would at least have an f number of 4.92. The results for this combination are also attached. The image distance from the lens combination is about a 100 to a 140 mm. However, this would require much longer slotted length tubes thereby adding to the cost of the system. The number of accessible u-v points is the same as that for the 150-250 combination. 

I am still trying to search for a much more concrete way of quantifying aberrations.

Attachment 1: ray.png
ray.png
Attachment 2: Schematic.png
Schematic.png
Attachment 3: 150-250uv.png
150-250uv.png
Attachment 4: 150-250error.png
150-250error.png
Attachment 5: 250-250.png
250-250.png
Attachment 6: 250-250error.png
250-250error.png
  12997   Wed May 17 18:08:45 2017 DhruvaUpdateOptical LeversBeam Profiling Setup

Andrew and I set up the razor blade beam profiling experiment for He-Ne lasers on the "SP" table.  Once I receive the laser safety training, I will make power measurements and fit it to an erfc curve from which I will calculate the gaussian profile of the beam. I'm attaching some pictures of the setup. 

Least count of the micrometer - 2 microns 

Laser  : Lumentum 22037130:1103P

Photodetector : Thor Labs PDA100A

Attachment 1: 1.jpg
1.jpg
Attachment 2: 2.jpg
2.jpg
Attachment 3: 3.jpg
3.jpg
Attachment 4: 4.jpg
4.jpg
Attachment 5: 5.jpg
5.jpg
  12996   Wed May 17 11:10:31 2017 SteveUpdateCamerasMC2 CCD video camera back in place

Olympus camera is removed and our old CCD camera is back to monitor the face of MC2

Quote:

Olympus SP570 UZ - without  IR blocker, set up as Atm.3  Camera distance to MC  face ~85 cm,  IOO-MC_TRANS_SUM 16,300 counts, Lexan cover on not coated viewport.

Image mode: RAW + JPG,  M-costum,  manual focus,  Lens: Olympus 4.6 - 92 mm, f2.8 - 4.5,  Apeture: F2.8 - 8,  Image pick up device: 1/2.33" CCD (primary color filter)

Atm.1,       212k.jpg of raw 15 MB,  exp 0.025s,   apeture 2.97,  f 4.6,   iso 64,  

Atm.2,        Copied through my Cannon S100  (  3.3 MB.jpg of raw from UFraw photo shop )I will look up the original raw file for details.

 

 

  12995   Wed May 17 08:19:59 2017 SteveUpdateSUS4.1M earthquake

Sus dampings recovered. ETMY oplev needs to be recentered.

GV May 17 11am: I shut down the BS, SRM, ITMX and ITMY watchdogs, as the coil-driver boards for these optics are presently not installed.
 

Attachment 1: eq_4.1_SantaBarbara.png
eq_4.1_SantaBarbara.png
Attachment 2: 4.1m_Isla_Vista_CA.png
4.1m_Isla_Vista_CA.png
  12994   Tue May 16 16:16:16 2017 SteveUpdatesafetysafety training

 Early surfs of India Jigyasa and Kaustubh received basic 40m specific safety traning.

Attachment 1: surfs2017.jpg
surfs2017.jpg
  12993   Mon May 15 20:43:25 2017 ranaConfigurationComputerscatastrophic multiple monitor failures

this is not the right one; this Ethernet controlled strip we want in the racks for remote control.

Buy some of these for the MONITORS.

Quote:

Surge protective power strip was install on Friday, May 5 in the Control Room

Computers not connected to the UPS are plugged into Isobar12ultra.

Quote:

That's a new failure mode. Probably we can't trust the power to be safe anymore.

Need Steve to order a couple of surge suppressing power strips for the monitors. The computers are already on the UPS, so they don't need it.

 

  12992   Mon May 15 19:21:04 2017 KojiUpdateComputer Scripts / ProgramsFSSslow / MCautolocker restarted

It seems that FSS slow servo stopped working.

I found that megatron was restarted (by Rana, to finish an apt-get upgrade) on ~18:47 PDT today.

controls@megatron|~> last -5
controls pts/0        192.168.113.216  Mon May 15 19:15   still logged in   
controls pts/0        192.168.113.216  Mon May 15 19:14 - 19:15  (00:01)    
reboot   system boot  3.2.0-126-generi Mon May 15 18:50 - 19:19  (00:29)    
controls pts/0        192.168.113.200  Mon May 15 18:43 - down   (00:04)    
controls pts/0        192.168.113.200  Mon May 15 15:25 - 17:38  (02:12)


FSSslow / MCautolocker were restarted on megatron.

  12991   Mon May 15 08:26:43 2017 ranaUpdateCDSSVN up in userapps/cds

I did an 'svn update' in userapps/cds/ which pulled in some changes from the sites as well as various CDS utilities in common/ and utilities/

This was to get Keith Thorne's get_data.m and get_data2.m scripts which I tested and they seem to be able to get data. No success with getting minute trend yet, but that may be a user error.

Update Monday 15-May: Our version of NDS client is 0.10 and we need to have 0.14 for this new method to work. Ubuntu12 lscsoft repo doesn't have newer nds client so we'll have to upgrade some OS.

  12990   Fri May 12 18:50:08 2017 gautamUpdateGeneralITM and BS coil driver + dewhite board pulled out

I've uploaded high-res photos + marked up schematics to the same DCC page linked in the previous page. I've noted the S/Ns of the ITM, BS and SRM boards on the page, I think it makes sense to collect everything on one page, and I guess eventually we will unify everything to a one or two versions.

To take the photos, I tried to reproduce the "LED light painting" technique reported here. I mounted the Canon EOS Rebel T3i on a tripod, and used some A3 sheets of paper to make a white background against which the board to be photographed was placed. I also used the new Macro lens we recently got. I then played around with the aperture and exposure time till I got what I judged to be good photos. The room lights were turned off, and I used the LED on my phone to do the "painting", from ~a metre away. I think the photos have turned out pretty well, the component values are readable.

Quote:

I first set the bias sliders to 0 on the MEDM screen (after checking that the nominal values were stored), then shut down the watchdogs, and then pulled out the boards for inspection + photo-taking.

 

  12989   Fri May 12 18:45:04 2017 rebeccaUpdateCamerasMC2 Pics with Olympus

Raw and JPG formats of the pictures are saved on the Mac in the control room and at this link:

https://drive.google.com/open?id=0B9WDJpPRYby1c2xXRHhfOExXNFU 

The camera was mounted using the JOBE arm wrapped around a small heavy piece of metal. The lights were kept on, the camera was zoomed in as closely as possible (so the light would take up most of the frame), F number of 8 was used, and shutter speeds from 1/2 to 1/100 seconds were used. 

The pictures still look a bit blurry, probably because looking back at the details of the image, the focal length was 86.34m (as short of a focal length would be ideal, and Olympus is capable of going down to 1m).

Next steps include looking at the saturation in the pictures and setting up a more stable mount. 

  12988   Fri May 12 12:34:55 2017 gautamUpdateGeneralITM and BS coil driver + dewhite board pulled out

I first set the bias sliders to 0 on the MEDM screen (after checking that the nominal values were stored), then shut down the watchdogs, and then pulled out the boards for inspection + photo-taking.

  12987   Fri May 12 01:36:04 2017 gautamUpdateGeneralSRM coil driver + dewhite board LISO modeling

I've made the LISO models for the dewhitening board and coil driver boards I pulled out.

Attached is a plot of the current noise in the current configuration (i.e. dewhitening board just has a gain x3 stage, and then propagated through the coil driver path), with the top 3 noise contributions: The op-amps (op3 and op5) are the LT1125s on the coil driver board in the bias path, while "R12" is the Johnson noise from the 1k input resistace to the OP27 in the signal path.

Assuming the OSEMs have an actuation gain of 0.016 N/A (so 0.064 N/A for 4 OSEMs), the current noise of ~1e-10 A/rtHz translates to a displacement noise of ~3e-15m/rtHz at ~100Hz (assuming a mirror mass of 0.25kg). 

I have NOT included the noise from the LM6321 current buffers as I couldn't find anything about their noise characteristics in the datasheet. LISO files used to generate this plot are attached.

Quote:

I've added marked-up schematics + high-res photographs of the SRM coil driver board and dewhitening board to the 40m DCC Document tree (D1700217 and D1700218). 

In the attached marked-up schematics, I've also added the proposed changes which Rana and I discussed earlier today. For the thick-film -> thin-film resistor switching, I will try and make a quick LISO model to see if we can get away with replacing just a few rather than re-stuff the whole board.

Since I have the board out, should I implement some of these changes (like AD797 removal) before sticking it back in and pulling out one of the ITM boards? I need to look at the locking transients and current digital limit-values for the various DoFs before deciding on what is an appropriate value for the output resistance in series with the coil.

Another change I think should be made, but I forgot to include on the markups: On the dewhitening board, we should probably replace the decoupling capacitors C41 and C52 with equivalent value electrolytic caps (they are currently tantalum caps which I think are susceptible to fail by shorting input to output).

 

Attachment 1: SRM_bypass_plus_CoilDriver.pdf
SRM_bypass_plus_CoilDriver.pdf
Attachment 2: liso.zip
  12986   Thu May 11 18:59:22 2017 gautamUpdateGeneralSRM coil driver + dewhite board initial survey

I've added marked-up schematics + high-res photographs of the SRM coil driver board and dewhitening board to the 40m DCC Document tree (D1700217 and D1700218). 

In the attached marked-up schematics, I've also added the proposed changes which Rana and I discussed earlier today. For the thick-film -> thin-film resistor switching, I will try and make a quick LISO model to see if we can get away with replacing just a few rather than re-stuff the whole board.

Since I have the board out, should I implement some of these changes (like AD797 removal) before sticking it back in and pulling out one of the ITM boards? I need to look at the locking transients and current digital limit-values for the various DoFs before deciding on what is an appropriate value for the output resistance in series with the coil.

Another change I think should be made, but I forgot to include on the markups: On the dewhitening board, we should probably replace the decoupling capacitors C41 and C52 with equivalent value electrolytic caps (they are currently tantalum caps which I think are susceptible to fail by shorting input to output).

Attachment 1: D010001-B_40m.pdf
D010001-B_40m.pdf D010001-B_40m.pdf D010001-B_40m.pdf D010001-B_40m.pdf
Attachment 2: D000183-C8_40m.pdf
D000183-C8_40m.pdf D000183-C8_40m.pdf D000183-C8_40m.pdf
  12985   Thu May 11 09:45:46 2017 ranaUpdateGeneralDAC / Coil Driver noise - SRM coil driver + dewhite board removed

I believe the ETMs and ITMs are different from the others.

  12984   Wed May 10 17:46:44 2017 gautamUpdateGeneralDAC / Coil Driver noise - SRM coil driver + dewhite board removed

I've removed the SOS coil driver (D010001-B, S/N B151, labelled "SRM") + Universal Dewhitening Board (D000183 Rev C, S/N B5172, labelled "B5") combo for SRM from 1X4, for photo taking + inspection.

I first shutdown the SRM watchdog, noted cabling between these boards and also the AI board as well as output to Sat. Box. I also needed to shutdown the MC2 watchdog as I had to remove the DAC output to MC2 in order to remove the SRM Dewhitening board from the rack. This connection has been restored, MC locks fine now.

 

  12983   Wed May 10 17:17:05 2017 gautamUpdateGeneralDAC / Coil Driver noise

Suspension Actuator noise:

There are 3 main sources of electronics noise which come in through the coil driver:

  1. Voltage noise of the coil driver.
    1. The input referred noise is ~5 nV/rHz, so not a big issue.
    2. The Johnson noise of the output resistor which is in series with the coil is sqrt(4*k*T*R) ~ 3 nV/rHz. We probably want to increase this resistor from 200 to 1000 Ohms once Gautam convinces us that we don't need that range for lock acquisition.
  2. Voltage noise of the dewhitening board.
    1. In order to reduce DAC noise, we have a "dewhitening" filter which provides some low passing. There is an "antiDW" filter in the digital part which is the inverse of this, so that when they are both turned on, the result is that the main signal path has a flat transfer function, but the DAC noise gets attenuated.
    2. In particular, ours have 2 second order filters (each with 2 poles at 15 Hz and 2 zeros at 100 Hz).
    3. We also have a passive pole:zero network at the output which has z=130, 530 Hz and p = 14, 3185 Hz.
    4. The dewhitening board has an overall gain of 3 at DC to account for our old DACs having a range of +/-5 V and our coil drivers having +/- 15 V power supplies. We should get rid of this gain of 3.
    5. The dewhitening board (and probably the coil driver) use thick film resistors and so their noise is much worse than expected at low frequencies.
  3. DAC voltage noise. 
    1. The General Standards 16-bit DACs have a noise of ~5 uV/rHz.
  4. the satellite box is passive and not a significant source of noise; its just a flaky construction and so its problematic.
Attachment 1: actuation.jpg
actuation.jpg
  12982   Wed May 10 16:57:52 2017 ranaUpdateCDSMCautolocker dead

I rebooted megatron around 12:20 today. It had dozens of stalled medm process (some of them there since February!). I couldn't kill them without them coming back like zombies, so I did sudo reboot.

  12981   Wed May 10 16:53:38 2017 ranaUpdateGeneralMICH NB - OL coupling

That's a good find.

  1. The OL control signal can be gotten from the DQ error signal. You just need to multiply it by the digital filters and the gain. The state of the filters and the gain can be gotten using matlab tools like getFotonFilt.m. For python ChrisW wrote a tool called foton.py which is in the GDS SVN. You should ask him for it. It requires access to some ROOT libraries to run.
  2. We should have sub budgets for everything like OL and thermal, etc. They should be automatically produced each time you run the main budget and should be separate pages in the same PDF file. Jamie / Chris may have something going along these lines so check to see if they are already on it.
  12980   Wed May 10 12:37:41 2017 gautamUpdateCDSMCautolocker dead

The MCautolocker had stalled - there were no additional lines to the logfile after 12:17pm (~20mins ago). Normally, it suffices to ssh into megatron and run sudo initctl restart MCautolocker - but it seems that there was no running initctl instance of this, so I had to run sudo initctl start MCautolocker. The FSS Slow control initctl process also seemed to have been terminated, so I ran sudo initctl start FSSslowPy.

It is not clear to me why the initctl instances got killed in the first place, but MC locks fine now.

  12979   Wed May 10 01:56:06 2017 gautamUpdateGeneralMICH NB - OL coupling

Last night, I tried to estimate the contribution of OL feedback signal to the MICH length error signal.

In order to do so, I took a swept sine measurement with a few points between 50 Hz and 500 Hz. The transfer function between C1:LSC-MICH_OUT_DQ and the Oplev Servo Output point (e.g. C1:SUS-BS_OL_PIT_OUT etc) was measured. I played around with the excitation amplitude till I got coherence > 0.9 for the TF measurement, while making sure I wasn't driving the Oplev error point too hard that side-lobes began to show up in the MICH control signal spectrum.

The Oplev control signal is not DQ-ed. So I locked the DRMI again and downloaded the 16k data "live" for ~5min stretch using cdsutils.getdata on the workstation. The Oplev error point is DQ-ed at 2k, but I found that the excitation amplitude needed for good SNR at the error point drove the servo to the limiter value of 2000cts - so I decided to use the control signal instead. Knowing the transfer function from the Oplev *_OUT* channel to C1:LSC-MICH_IN1_DQ, I backed out the coupling - the transfer function was only measured between 50 Hz and 500 Hz, and no extrapolation is done, so the estimation is only really valid in this range, which looks like where it is important anyways (see Attachment #2, contributions from ITMX, ITMY and BS PIT and YAW servos added in quadrature).

I was also looking at the Oplev servo shapes and noticed that they are different for the ITMs and the BS (Attachment #1). Specifically, for the ITM Oplevs, an "ELP15" is used to do the roll-off while an "ELP35" is employed in the BS servo (though an ELP35 also exists in the ITM Oplev filter banks). I got lost in an elog search for when these were tuned, but I guess the principles outlined in this elog still hold and can serve as a guideline for Oplev loop tweaking.

Coil driver noise estimation to follow

Quote:

I think the most important next two items to budget are the optical lever noise, and the coil driver noise. The coil driver noise is dominated at the moment by the DAC noise since we're operating with the dewhitening filters turned off.

GV 10 May 12:30pm: I've uploaded another copy of the NB (Attachment #3) with the contributions from the ITMs and BS separated. Looks like below 100Hz, the BS coupling dominates, while the hump/plateau around 350Hz is coming from ITMX.

Attachment 1: OL_BS_ITM_comp.pdf
OL_BS_ITM_comp.pdf
Attachment 2: C1NB_disp_40m_MICH_NB_8_May_2017.pdf
C1NB_disp_40m_MICH_NB_8_May_2017.pdf
Attachment 3: C1NB_disp_40m_MICH_NB_10_May_2017.pdf
C1NB_disp_40m_MICH_NB_10_May_2017.pdf
  12978   Tue May 9 15:23:12 2017 SteveConfigurationComputerscatastrophic multiple monitor failures

Gautam and Steve,

Surge protective power strip was install on Friday, May 5 in the Control Room

Computers not connected to the UPS are plugged into Isobar12ultra.

Quote:

That's a new failure mode. Probably we can't trust the power to be safe anymore.

Need Steve to order a couple of surge suppressing power strips for the monitors. The computers are already on the UPS, so they don't need it.

 

Attachment 1: Trip-Lite.jpg
Trip-Lite.jpg
  12977   Mon May 8 21:53:56 2017 ranaSummarySEIattempt to get seismic BLRMS minute trend

I tried to get some minute trend data today, but was unable to get it from inside or outside the control room using our matlab or python tools.

It seems the NDS2 interface will not work anywhere since it needs our minute trends to be written as frames; in the last version that Jamie left us, our minute trend frame files are not being written since they lead to periodic daqd crashes.

From inside the control room, we can get the minute trend (only with DataViewer). I've attached 30 days of BS_X just to show its real.

We can get the numerical data from the Grace plot window using the menu option Data->Export->ASCII.

You must select all of the 'Write Sets' to get all of the traces in the plot window. The resulting ascii file is not in a great format, but its not terrible.

Attachment 1: BLRMS_trend.png
BLRMS_trend.png
  12976   Sat May 6 21:52:11 2017 ranaUpdateGeneralMICH NB questions

I think the most important next two items to budget are the optical lever noise, and the coil driver noise. The coil driver noise is dominated at the moment by the DAC noise since we're operating with the dewhitening filters turned off.

  12975   Fri May 5 12:10:53 2017 gautamUpdateGeneralMICH NB questions

Quote:
Is suspension thermal noise missing? I take it "Thermal" refers just to thermal things going on in the optic, since I don't see any peaks at the bounce/roll modes as I would expect from suspension thermal noise. What goes into the GWINC calculation of seismic noise? Does it include real 40m ground motion data and our seismic stacks? I'm surprised to see such a sharp corner in the "Dark Noise" trace, did you apply the OLG correction to a measured dark noise ASD? (The OLG correction only needs to be applied to the in-lock error signals to recover open loop behavior, there is no closed loop when you're measuring the dark noise so nothing to correct for.)


I've included the suspension thermal noise in the "Thermal" trace, but I guess the GWINC file I've been using to generate this trace only computes the thermal noise for the displacement DoF. I think this paper has the formulas to account for them, I will look into including these.

For the seismic noise, I've just been using the seis40.mat file from the 40m SVN. I think it includes a model of our stacks, but I did not re-calculate anything with current seismometer spectra. In the NB I updated yesterday, however, I think I was off by a factor of sqrt(3) as I had only included the seismic noise from 1 suspended optic. I've corrected this in the attached plot.

For the dark noise, you are right, I had it grouped in the wrong dictionary in the code so it was applying the OLG inversion. I've fixed this in the attached plot.
Attachment 1: C1NB_disp_40m_MICH_NB_30_April_2017.pdf
C1NB_disp_40m_MICH_NB_30_April_2017.pdf
  12974   Fri May 5 10:13:02 2017 ericqUpdateGeneralMICH NB questions
Is suspension thermal noise missing? I take it "Thermal" refers just to thermal things going on in the optic, since I don't see any peaks at the bounce/roll modes as I would expect from suspension thermal noise.

What goes into the GWINC calculation of seismic noise? Does it include real 40m ground motion data and our seismic stacks?

I'm surprised to see such a sharp corner in the "Dark Noise" trace, did you apply the OLG correction to a measured dark noise ASD? (The OLG correction only needs to be applied to the in-lock error signals to recover open loop behavior, there is no closed loop when you're measuring the dark noise so nothing to correct for.)
  12973   Fri May 5 08:41:42 2017 SteveUpdateCamerasMC2 resonant pictures

Olympus SP570 UZ - without  IR blocker, set up as Atm.3  Camera distance to MC  face ~85 cm,  IOO-MC_TRANS_SUM 16,300 counts, Lexan cover on not coated viewport.

Image mode: RAW + JPG,  M-costum,  manual focus,  Lens: Olympus 4.6 - 92 mm, f2.8 - 4.5,  Apeture: F2.8 - 8,  Image pick up device: 1/2.33" CCD (primary color filter)

Atm.1,       212k.jpg of raw 15 MB,  exp 0.025s,   apeture 2.97,  f 4.6,   iso 64,  

Atm.2,        Copied through my Cannon S100  (  3.3 MB.jpg of raw from UFraw photo shop )I will look up the original raw file for details.

 

Attachment 1: P5040028MC2c.jpg
P5040028MC2c.jpg
Attachment 2: IMG_3682.JPG
IMG_3682.JPG
Attachment 3: IMG_3688.JPG
IMG_3688.JPG
  12972   Thu May 4 19:03:15 2017 gautamUpdateGeneralDRMI locking - preliminary MICH NB

Summary:

I've been playing around with Evan's NB code trying to put together a noise budget for the data collected during the DRMI locks last week. Here is what I have so far.

Attachment #1: Sensing matrix measurement.

  • This is basically to show that the MICH error signal is mostly in AS55Q.
  • The whitening gain used was 0dB, and the demod phase was -82 degrees.
  • The MICH sensing response was 5.31*10^8 V/m, where V is the demod board output. The 40m wiki RFPD page for AS55 says the RF transimpedance is ~550ohms, and I measured the Demod Board puts out 5.1V of IF signal (measured at after the Preamp, which is what goes to the ADC) for 1V of RF signal at the PD input. Using these numbers, and assuming a PD responsivity of 0.8 A/W at 1064nm, the sensing response is 2.37*10^5 W/m. I don't have a feeling yet for whether this is a reasonable number, but it would be a number to compare to what my Finesse model tells me to expect, for example.
  • Actuator calibration used to arrive at these numbers was taken from this elog

Attachment #2: MICH OLTF measurement vs model

  • In order to build the MICH OLTF model, I used MATLAB to put together the following transfer functions:
    • BS pendulum
    • Digital servo filters from LSC_MICH
    • Violin mode filters 
    • Analog/Digital AA and AI filters. For the digital AA/AI filters, I took the coefficients from /opt/rtcds/rtscore/release/src/fe/controller.c
  • The loop measurement was taken with digital filter modules FM1, FM2, FM3, FM7, FM9 engaged. 
  • In order to fit the model to the measurement, I tried finding the best-fit values for an overall loop gain and delay. 
  • The agreement between model and measurement isn't stellar, but I decided to push ahead for a first attempt. This loop TF was used to convert various noises into displacement noise for plotting.

Attachment #3: Noise budget

  • It took me a while to get Evan's code going, the main changes I made were to use nds2 to grab data instead of GWPy, and also to replace reading in .txt files with importing .mat files. This is a work in progress.
  • Noises plotted:
    • Measured - I took the in loop error signal and estimated the free-running displacement noise with the model OLTF, and calibrated it into metres using the sensing response measurement. This looks consistent with what was measured back in Dec 2015.
    • Shot noise - I used the measured DC power incident on the PD, 13mW, RF transimpedance of 550 V/A, and the V/m calibration factor mentioned above, to calculate this (labelled "Quantum Noise").
    • Dark noise - measured with PSL shutter closed.
    • Seismic noise, thermal noise, gas noise - calculated with GWINC

I think I did the various conversions/calibrations/loop algebra correctly, but I may have overlooked something. Now that the framework for doing this is somewhat set up, I will try and put together analogous NBs for PRCL and SRCL. 

GV 22 August 2017: Attachment #4 is the summary of my demod board efficiency investigations, useful for converting sensing measurement numbers from cts/m to W/m.

Attachment 1: DRMI_noArms_April30.pdf
DRMI_noArms_April30.pdf
Attachment 2: MICH_OLTF.pdf
MICH_OLTF.pdf
Attachment 3: C1NB_disp_40m_MICH_NB_30_April_2017.pdf
C1NB_disp_40m_MICH_NB_30_April_2017.pdf
Attachment 4: 40m_REFL_RFPDs_efficiency.pdf
40m_REFL_RFPDs_efficiency.pdf
  12971   Thu May 4 09:52:43 2017 ranaConfigurationComputerscatastrophic multiple monitor failures

That's a new failure mode. Probably we can't trust the power to be safe anymore.

Need Steve to order a couple of surge suppressing power strips for the monitors. The computers are already on the UPS, so they don't need it.

  12970   Thu May 4 08:00:54 2017 SteveUpdatesafetysafety training

Freshmen Rebecca Zhang as " work study undergrad "  received 40m specific basic safety training yesterday.

  12969   Wed May 3 18:45:45 2017 ranaUpdateGeneralDRMI locking

Quote:
Comparing counts doesn't get you anywhere; each PD has different whitening gain which may vary from measurement to measurement. The better thing to compare is Volts coming out of the demod board, since this (hopefully) only changes when we touch the PD or analog signal chain; this is what I used for the most recent DRMI sensing measurements. (ELOG 11589) We have calibrated actuator channels in the CAL model, which will give you the control signal in m for the DRMI lengths. Perhaps you can convert your sensing matrix measurement to demod board output volts per meter to compare with the last measurement.

Also, the monitor ports are the LEMO ports to the left; the SMA ports where the signal is coming from are from a daughter board that has a better output opamp that the nominal output; we're using the same output on the REFL11 and AS55 demod boards.


Wrong! RTFS.

SMA outputs are the bare, passive outputs of the mixer/lowpass.
TNC outputs are the low-noise, acti amplified outputs via the daughter board.
LEMO outputs are the high noise, G=2, LT1125 buffered outputs
  12968   Wed May 3 17:16:30 2017 PrafulUpdateElectronicsNew Altium Schematic Design for Microphone Amp

I made an Altium schematic for the microphone amplifier circuit for fabrication.

mic_schematicv2.pdf

Attachment 1: mic_schematicv2.pdf
mic_schematicv2.pdf
  12967   Wed May 3 16:47:45 2017 KojiUpdateGeneralPI pzt inventory check

I also have a functional one on my desk, which has one of the wires repaired.

Quote:

One is broken, two are ready to steer green and 3 available in un known condition

 

 

  12966   Wed May 3 16:46:18 2017 KojiConfigurationComputerscatastrophic multiple monitor failures

- Is there any machine that can handle 4K? I have one 4K LCD for no use.
- I also can donate one 24" Dell

  12965   Wed May 3 16:12:36 2017 johannesConfigurationComputerscatastrophic multiple monitor failures

It seems we lost three monitors basically overnight.

The main (landscape, left) displays of Pianosa, Rossa and Allegra are all broken with the same failure mode:

their backlights failed. Gautam and I confirmed that there is still an image displayed on all three, just incredibly faint. While Allegra hasn't been used much, we can narrow down that Pianosa's and Rossa's monitors must have failed within 5 or 6 hours of each other, last night.

One could say ... they turned to the dark side cool

Quick edit; There was a functioning Dell 24" monitor next to the iMac that we used as a replacement for Pianosa's primary display. Once the new curved display is paired with Rossa we can use its old display for Donatella or Allegra.

  12964   Wed May 3 16:02:36 2017 SteveUpdateGeneralPI pzt inventory check

One is broken, two are ready to steer green and 3 available in un known condition

 

Attachment 1: IMG_3678.JPG
IMG_3678.JPG
Attachment 2: PIpztETMYgreen.jpg
PIpztETMYgreen.jpg
  12963   Wed May 3 16:00:00 2017 gautamSummaryGeneralNetwork Topology Check

[johannes, gautam]

I forgot we had done this last year already, but we updated the control room network switch labels and double checked all the connections. Here is the status of the connections and labels as of today:

There are a few minor changes w.r.t. labeling and port numbers compared to the Dec 2015 entry. But it looks like there was no IP clash between Rossa and anything (which was one of the motivations behind embarking on this cleanup). We confirmed by detatching the cable at the PC end of Rossa, and noticed the break in the ping signals. Plugging the cable back in returned the pings. Because Rossa is currently un-bootable, I couldn't check the MAC address.

We also confirmed all of this by using the web browser interface for the switch (IP = 192.168.113.249).

Attachment 1: Network_topology_3May2017.pdf
Network_topology_3May2017.pdf
  12962   Mon May 1 21:45:54 2017 ericqUpdateGeneralDRMI locking
Comparing counts doesn't get you anywhere; each PD has different whitening gain which may vary from measurement to measurement. The better thing to compare is Volts coming out of the demod board, since this (hopefully) only changes when we touch the PD or analog signal chain; this is what I used for the most recent DRMI sensing measurements. (ELOG 11589) We have calibrated actuator channels in the CAL model, which will give you the control signal in m for the DRMI lengths. Perhaps you can convert your sensing matrix measurement to demod board output volts per meter to compare with the last measurement.

Also, the monitor ports are the LEMO ports to the left; the SMA ports where the signal is coming from are from a daughter board that has a better output opamp that the nominal output; we're using the same output on the REFL11 and AS55 demod boards.
  12961   Mon May 1 17:14:58 2017 SteveUpdateCamerasETMY & MC2 ccd cameras removed

MC2 ccd camera is replaced by Olympus 570 zoom temporarly.

So as the ETMY ccd camera is replaced by Cannon Rebel.

Both viewport are under Lexan protection and covered by Aluminum foil....still, turn all lighting off if you do not want room light in the IFO

 

Do not remove Lexan shield!

 

  12960   Mon May 1 16:29:51 2017 gautamUpdateGeneralDRMI locking

For the traces I posted, I had not turned on the whitening for the SRCL sensing PD (REFL55). However, I took a spectrum on a subsequent lock, with the analog whitening + digital dewhitening turned on for all 3 PDs (AS55, REFL11 and REFL55), and the HF part of the SRCL spectrum still looked anomalous. I'm putting together the detailed NB, but here's a comparison between the signals from the 3 RFPDs with the PSL shutter closed (but whitening engaged, and with the analog gains at the same values as used during the locking).

 

To convert the y-axis into m/rtHz, I used data from a sensing matrix measurement I took yesterday night during a DRMI lock - I turned on lines between 300 Hz and 325 Hz for the 3DOFs for ~5 minutes, downloaded the RFPD error signal data and did the demodulation. I used numbers from this elog to convert the actuator drive from cts to m. The final numbers I used were:

MICH (AS55_Q):   8.706 * 10^11 cts/m

PRCL (REFL11_I): 2.757 * 10^12 cts/m

SRCL (REFL55_I): 1.995 * 10^10 cts/m

So it looks like there may be something weird going on with the REFL55 signal chain. Looking at the LSC rack (and also suggested by an elog search), it looks like the demodulation is done by a demod board labelled "POP55" - moreover, the demodulated outputs are taken not from the regular output ports on this board, but from the "MON" ports on the front panel. 

Quote:

one of these signals does not look like the others: explanation?

 

Attachment 1: LSC_sensingNoise.pdf
LSC_sensingNoise.pdf
  12959   Sun Apr 30 13:24:00 2017 ranaUpdateCamerasAttempting to Load Camera Client

We ought to put the camera software on the shared disk; I don't think there's any speed reasons that it needs to be local.

Its OK to use optimus as the camera server for testing at the moment, but once we have things running, we'll install a few more cameras. With ~4-5 GigE running, we may not want to share with optimus, since we're also using it for comsol and skymap calculations.

  12958   Fri Apr 28 22:50:35 2017 johannesUpdateCamerasAttempting to Load Camera Client

You'll likely have to run camera_server.py using the same ini file first before you can use the client. Since the pylon installation is not on the shared drive but only local to optimus at the moment you would have to do it from there. You'll need to add /opt/pylon5/lib64/ to LD_LIBRARY_PATH or it won't find some required libraries. I couldn't start up the server all the way, probably because we need to define some slow EPICS channels before running the server script, as Joe points out in his document T1300202. You'll find instructions how to do that for example in this elog.

 

Quote:

Using /ligo/apps/linux-x86-64/camera/bin/camera_client.py -c  /opt/rtcds/caltech/c1/scripts/GigE/SnapPy/L1-CAM-MC1.ini, the Python script was able to run without error but didn't show any video feed from the camera in GStreamer. Problem might be in the configuration of the camera in the .ini file.
 

 

  12957   Fri Apr 28 19:32:06 2017 gautamUpdateGeneralDRMI locking - PRCL angular FF

I took a closer look at the POP QPD/ PRC angular feedforward situation yesterday. I thought it would be useful to have a POP QPD MEDM screen. Looking at the PIT and YAW channel filter modules, the anti-whitening filters seemed different from what we have for other channels that are connected to the Pentek interface board (e.g. MCL). So I copied over the 150:15 (z:p) filter, and also turned on a 60Hz comb. The LSC offsets script does not set the dark offsets for this QPD, so I manually put in the dark offsets for the PIT, YAW and SUM channels as well. For the locking, I first locked the arms on IR an dither aligned them. Then I locked the PRMI on carrier, ran the PRC dither alignment, and went over to the ITMX pickoff table and centered the beam on the QPD by making the PIT and YAW channel timeseries oscillate around approximately zero. 

After these tweaks, I collected ~40mins of data with the angular FF OFF/ON. I did not DC couple the ITM Oplev servos, but Eric tells me that this did not make a difference to the achievable subtraction in the past. Here is the frequency domain multicoherence analysis - I used the BS_X and BS_Y seismometer channels as witnesses. I've also put a plot with what the raw FF filter coefficients look like (no fitting yet). 

      

Looks like we can do better for both DOFs - it even seems like we are injecting noise with the current FF filters in some bands, perhaps we can do a better job of rolling off the filters outside the band of interest. Eric and I were discussing MATLAB's "reduce" routine for this purpose, I will play around with it and see if I get a better fit.

Unfortunately, I encountered a strange error when trying to pull data with nds2 today, it kept complaining RuntimeError: Too many channels or too much data requestedeven though I have pulled longer stretches of data for more channels with 16k sampling rate as recently as last week. Shorter duration requests (<600 seconds) seemed to work fine though... So I had to use cds.getdata to pull the data, and they're much too large to attach. Has anyone else encountered a similar error?


The mystery of the spots on the ITMs when the PRC is locked on carrier remains - after talking this over with Koji, we figured that even with the carrier resonant, the spot will be much dimmer than the spots when the arms are locked, but what I see on the cameras is still a pretty beefy spot. The real cavity mode is actually visible where it should be (I marked the locations of the spots with arms well-aligned with a marker on the monitors), as given away by some twinkling that is visible only when the cavity is locked. But what ghost beam is so intense it looks almost as bright as when the arm is locked?

GV 10pm 28 April 2017: Turns out this is the spot from the single bounce off the ETM transmitting back through the ITM and hitting the suspension cage (hence the bright spot). Johannes and I confirmed by moving the ETM, the spot moved with it. I just never paid attention to this spot before.

Attachment 1: PRC_angularFF.pdf
PRC_angularFF.pdf
Attachment 2: PRC_TFs.pdf
PRC_TFs.pdf
  12956   Fri Apr 28 18:01:56 2017 rebeccaUpdateCamerasAttempting to Load Camera Client

Using /ligo/apps/linux-x86-64/camera/bin/camera_client.py -c  /opt/rtcds/caltech/c1/scripts/GigE/SnapPy/L1-CAM-MC1.ini, the Python script was able to run without error but didn't show any video feed from the camera in GStreamer. Problem might be in the configuration of the camera in the .ini file.
 

  12955   Fri Apr 28 13:56:26 2017 ranaUpdateGeneralDRMI locking

one of these signals does not look like the others: explanation?

  12954   Fri Apr 28 02:04:36 2017 gautamUpdateGeneralDRMI locking

I got a couple of ~30min long DRMI lock stretches today. The settings I used are essentially the same as what I had back in November. Though we have since made some changes to the IMC RF signal chain, I guess it is not unreasonable that the LSC Demod phases that worked then work now as well. 

In the lock stretches, I did the following:

  • Took loop measurements for MICH, PRCL, SRCL
  • Turned on the sensing oscillator lines for error signal calibration
  • Tried turning on the analog whitening on AS55, REFL11 and REFL55. The latter two worked fine, but everytime I turned the REFL55 whitening on, I broke the lock. I'm also unable to acquire lock if I leave the whitening turned on all the time. The ADC overflow indicators also indicate frequent overflows when I turn the whitening on. Oddly, this seems to happen even if I turn the analog whitening gain to 0dB - the signals look well within the ADC range on dataviewer and DTT timeseries mode. Not sure what's going on here, I will investigate further tomorrow.
  • We should have some stretches where we can look at the possibility of seismic feedforward for some DRMI length DOFs.

On the side, I'm also looking at whether the PRC angular feedforward filters, last trained in October 2016, remain valid. Even post midnight, I am unable to lock the DRMI without turning on the FF, and looking at the POP QPD PIT and YAW signal spectra with the FF on vs FF off, there is definitely some improvement in the 1-4Hz band (plot to follow), question is whether we can do better and hence improve the DRMI duty cycle/ make the lock acquisition easier. To this end, I centered the beam on the POP QPD after locking and dither aligning the PRC on carrier, and have taken some data to look at.

So, much data analysis to follow - the idea is to put together a DRMI noise budget with Evan's NB code. For now, here are the uncalibrated control signal spectra.

Attachment 1: 20170428_DRMI.pdf
20170428_DRMI.pdf
  12953   Thu Apr 27 17:55:33 2017 SteveUpdateCameraswhich camera to use for IR scatterring pictures

Yesterday I failed to take good pictures of ETMY  resonant arm of 1064 nm with Cannon Rebel T3i in RAW 22-27Mp & JPG dual- format. UFRaw file converter worked well. The IR blocker filter seems to be too good.

Today I used Olympus SP-570UZ ( without IR blocker), in raw format of 15Mp, fl 22.4mm, 15s including 2-3s flashlight,  f/8 and auto focus  This is just too much scattered IR for the Olympus.

Overexposed raw picture' jpg is shown  at the PSL with diffraction patter of the camera.

I'll go back using  the Nikon D40 with zoom 55-200mm as this Atm2 of May 2007 : manual focus, 15s, f/4-5.6, ISO 560,  826KB

Attachment 1: P4270081RAWolym.jpg
P4270081RAWolym.jpg
Attachment 2: Img0344.jpg
Img0344.jpg
  12952   Thu Apr 27 16:41:13 2017 Eric GustafsonUpdateLSC Status of the 40 m PD Frequency Response Fiber System
There two reports in the DCC describing the state of the system as of October 2014 including: (1)  Alex Cole’s “T1300618 Automated photodiode Frequency Response Measurement System” and a Wiki  created by Alex Cole where there are some instructions on the Master Script at https://wiki.ligo.caltech.edu/ajw?AlexanderCole    

And (2)  P140021 “Final Report: Automated Photodiode Frequency Response Measurement System for 40m Lab” by Nichin Sreekantaswamy and also as part of Nichin’s report by there is an archive of data at   https://wiki-40m.ligo.caltech.edu/Electronics/PDFR%20system   

I made a visual inspection of the system and saw that the following fibers collimators are still mounted in alignment mounts and the fiber is attached and pointed at a photodetector but possibly not aligned. 

ASP Table

Photodetector Label                             Fiber Label

REFL11                                              REFL55 Fiber on mount        

REFL33                                              REFL33 Fiber on mount

REFL55                                              REFL11 Fiber on mount

REFL165                                            No Fiber

AS55                                                   AS55 Fiber on mount

MCREFPD                                         MCREFPD Fiber on mount

No PD                                                 Loose unlabeled Fiber No mount

 

ITMX Optics Table

Photodetector Label                             Fiber Label

POX11                                                POX11 on mount

Unlabeled PD                                      POP22/POP110 on mount

NO PD                                                 POP55 loose fiber No mount

 

The RF switch seems to be hooked up and there is a fiber running from the Diode Laser module to the fiber splitter module. So REFL 11 and REFL545 seem to be illuminated by the wrong fiber. I’ll try and run the software on Monday and check to see if I need to move the fibers or just relabel them.

ELOG V3.1.3-