40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
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ID Date Author Type Categorydown Subject
  11096   Wed Mar 4 00:50:36 2015 ranaBureaucracyTreasureTransitioned DARM to AS55Q, some other work

Just in case there was some confusion, the champagne on my desk is not to be opened before I get back, no matter how many signals are transitioned to RF.

  11124   Mon Mar 9 16:50:35 2015 Champagne DuckFrogsTreasureCelebrating Lock

Attachment 1: 2015-03-09_16.35.47.jpg
2015-03-09_16.35.47.jpg
  11369   Mon Jun 22 14:21:42 2015 SteveMetaphysicsTreasureJenne and Den graduated

Last supper before departing at  "Grazie" El Portal. All the best on your journey!

Attachment 1: ls.jpg
ls.jpg
  11986   Thu Feb 11 14:28:50 2016 SteveUpdateTreasure091415 declared

   Beautifully Done

   Chirp

  what is next?

Atm 3, Ron Drever could not celebrate with us because of health issues.

 

Attachment 1: 091415declared.jpg
091415declared.jpg
Attachment 2: You_were_right!.jpg
You_were_right!.jpg
Attachment 3: P1080312.JPG
P1080312.JPG
  12007   Wed Feb 24 09:06:25 2016 SteveUpdateTreasurethe way it happened

 Celebration

Quote:

   Beautifully Done

   Chirp

  what is next?

Atm 3, Ron Drever could not celebrate with us because of health issues.

 

 

Attachment 1: IMG_0120.JPG
IMG_0120.JPG
  12562   Fri Oct 14 15:47:00 2016 ranaUpdateTreasurefilters + clip

I say just fix the clipping. Don't worry about the PRM OSEM filters. We can do that next time when we put in the ITM baffles. No need for them on this round.

  12694   Fri Jan 6 17:00:26 2017 ranaFrogsTreasureVideo of Lab Tour

In this video: https://youtu.be/iphcyNWFD10, the comments focus on the orange crocs, my wrinkled shirt, and the first aid kit.

  12917   Wed Mar 29 16:38:00 2017 SteveOmnistructureTreasuresus fiber illluminated
Attachment 1: fiber.jpg
fiber.jpg
  12919   Thu Mar 30 10:41:56 2017 ranaOmnistructureTreasuresus fiber illluminated

Very, very cool!  yes

  12922   Fri Mar 31 16:10:33 2017 SteveUpdateTreasureLes Guthman

Les Guthman interviews  gradstudent Graig.

Main laser emergency shut off was acuated by accident during this fiming. The laser is turned on.

  13140   Tue Jul 25 00:03:01 2017 ranaOmnistructureTreasurecoffee pot lid

I have recommissioned the Zojirushi coffee pot lid. You may, once again, align the dots in order to make the carafe pourable.

Details:

The Zojirushi lid is a two part mechanism:

  1. The top part of the lid must be removed for cleaning.
  2. When replacing the lid the two components must be aligned to < 3 mrad precision so that the "teeth" are able to land in the groove.
  3. There is a 4-fold degeneracy in this process. To break the degeneracy, align the dot on top with the spout gap (visible from the bottom view).
  4. After proper alignment and mating, the two parts should snap together and the relative alignment wiggle available should be < 2 mrad.
  5. After screwing the two-piece lid onto the carafe, ensure that the 2 dots are separated by < 170 deg in the closed position.
  14124   Thu Aug 2 16:30:08 2018 SteveUpdateTreasuretime capsule location

I 've just found this time capsule note from Nov. 26, 2000 by Kip Thorne:  LIGO will discover gravitational waves by Dec.31, 2007

Quote:

   Beautifully Done

   Chirp

  what is next?

Atm 3, Ron Drever could not celebrate with us because of health issues.

 

 

Attachment 1: time_capsule.JPG
time_capsule.JPG
  14265   Fri Nov 2 09:47:57 2018 SteveMetaphysicsTreasureZojirushi is dead

     It took at least ten years to rust away. crying

Attachment 1: DSC01773.JPG
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Attachment 2: zoji.JPG
zoji.JPG
  14271   Mon Nov 5 15:55:39 2018 SteveMetaphysicsTreasureZojirushi is dead

We have no coffee machine.

We are dreaming about it

We still do not have it.

Attachment 1: zoji.JPG
zoji.JPG
  14272   Tue Nov 6 09:45:32 2018 aaronMetaphysicsTreasureZojirushi is dead

New all organic machine.

  16441   Sun Oct 31 14:21:31 2021 ranaHowToTreasureIFOCad

IFOcad model/video of the AEI 10m interferometer:

https://10m.aei.mpg.de/design-and-sensitivity/

  16727   Tue Mar 15 13:49:44 2022 Ian MacMillanBureaucracyTreasureNew Screwdriver Bits

I have received the new screwdriver bits that will work with the two electric screwdrivers we have. I have distributed them in the 40m. Some are in the electronics stations and some are in the toolbox in the lab. The new electric screwdriver (which looks like a drill but takes typical screwdriver bits) is in the room with the workshop. It is in the blue Makita box. For some reason, lots of the old bits were rounded because of incorrect use. I have thrown the unuseable ones out.

I also requested some screw extractors in case we need them. the one we have now is really big and may not work on smaller screws.

  17139   Wed Sep 14 15:40:51 2022 JCUpdateTreasurePlastic Containers

There are brand new empty plastic containers located inside the shed that is outside in the cage. These can be used for organizing new equipment for CDS, or cleanup after Wednesday meetings

Attachment 1: B0DD2BEC-E57E-4AA2-8672-2ABB41F44F84.jpeg
B0DD2BEC-E57E-4AA2-8672-2ABB41F44F84.jpeg
  17099   Tue Aug 23 14:59:15 2022 JCUpdateToolsNew Toolbox at Y-End

A new tool box has been placed at the Y-end! Each drawer has its label so PLEASE put the tools back in their correct location. In addition to this, Each tool has its assigned tool box, so PLEASE RETURN all tools to their designated tool box. The tools can be distinguished by a writing or heat shrink which corresponds to the color of the tool chest or location. Photo #2 is an example of how the tools have been marked.

Each toolbox from now on will contain a drawer for the folllowing: Measurements, Allen Keys, Pliers and Cutters, Screwdrivers, Zipties and Tapes, Allen Ball Drivers, Crescent Wrenches, Clamps, and Torque Wrenches/ Ratchets.

Attachment 1: 9AFD3E49-0C5B-4626-889A-0A5C62590AD7.jpeg
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99EC2EB1-EEA0-4AD8-B6D7-A494431E91E5.jpeg
  14047   Mon Jul 9 17:29:28 2018 Udit KhandelwalSummaryTip-TIltTipTilt mirror holder final changes

Final Summary of changes to mirror holder in Tip-Tilt holder.

Determining minimum range for Side Clamp:

1. The initial distance b/w wire-release point and mirror assembly COM = 0.265 mm


2. But this distance is assuming that wire-release point is at mid-point of clamp. So I'm settling on a range of +/- 1mm. The screenshots below confirm range of ~1mm between (1) side screw & protrusion and (2) clamp screw and clamp.

Determining length of tilt-weight assembly rod at the bottom to get \pm 20mRad range

The tilt-weight assembly is made from following Mcmaster parts:
Rod   - 95412A864 18-8 SS  #2-56 Threaded Rod
Nuts  - 91855A103 18-8 SS #2-56 Acorn Cap Nut

Since the weights are fixed, only rod length can be changed to get the angle range.

tan \theta =\frac{d}{h}

d= h \times tan\theta = 34.25\text{mm} \times tan(20 \text{mRad}) = 0.69 \text{mm}
So a range of 1 mm between nut's inner face and mirror-holder face should be enough. Since holder is 12 mm thick, rod length = 12mm + 2 x 1mm + 2 x (nut length) = 12 + 2 + 9.6 = 23.6 mm = 0.93 inch. So a 1" rod from Mcmaster will be fine.

Attachment 4: 2-1.png
2-1.png
  14439   Thu Feb 7 17:27:53 2019 KojiSummaryTip-TIltFive FiveNine Optics Optics delivered

5 PR3/SR3 optics from FiveNine Optics were delivered. The data sheets were scanned and uploaded to the following wiki page. https://wiki-40m.ligo.caltech.edu/Aux_Optics

  14442   Fri Feb 8 00:20:56 2019 gautamSummaryTip-TIltFive FiveNine Optics Optics delivered

They have been stored on the 3rd shelf from top in the clean optics cabinet at the south end. EX

Quote:

5 PR3/SR3 optics from FiveNine Optics were delivered. The data sheets were scanned and uploaded to the following wiki page. https://wiki-40m.ligo.caltech.edu/Aux_Optics

  14444   Fri Feb 8 20:35:57 2019 gautamSummaryTip-TIltCoating spec

[Attachment #1]: Computed spectral power transmissivity (according to my model) for the coating design at a few angles of incidence. Behavior lines up well with what FNO measured, although I get a transmission that is slightly lower than measured at 45 degrees. I suspect this is because of slight changes in the dispersion relation assumed and what was used for the coating in reality.

[Attachment #2]: Similar information as Attachment #1, but with the angle of incidence as the independent parameter in a continuous sweep. 

Conclusion: The coating behaves in a way that is in reasonable agreement with our model. At 41.1 degrees, which is what the PR3 angle of incidence will be, T<50 ppm, which was what we specified. The larger range of angles was included because originally, we thought of using this optic as a substitute for SR3 as well. But I claim that for the shorter SRC (signal recycling as opposed to RSE), we will not end up using the new optic, but rather go for the G&H mirror. In any case, as Koji pointed out, ~50 ppm extra loss in the RC will not severely limit the recycling gain. Such large variation was not seen in the MC analysis because we only varied the angle of incidence by +/- 0.5 degrees about the nominal design value of 41.1 degrees.

Attachment 1: specRefl.pdf
specRefl.pdf
Attachment 2: AoIscan.pdf
AoIscan.pdf
  14474   Tue Mar 5 15:56:27 2019 gautamSummaryTip-TIltDiscussion points about TT re-design

Chub, Koji and I have been talking about Udit's re-design. Here are a few points that were raised. Chub/Koji can add to/correct where necessary. Summary is that this needs considerable work before we can order the parts for a prototype and characterize it. I think the requirements may be stated as:

  1. The overall pendulum length should be similar to that of the SOS, i.e. ~0.3m (current length is more like 0.1m) such that the eigenfrequencies are lowered to more like ~1 Hz. Mainly we wan't to avoid any overlap with the stack eigenmodes. This may require an additional stiffening piece near the top of the tower as we have for the SOS. What is a numerical way to spec this?
  2. The center of the 2" optic should be 6" from the table.
  3. The mass of the optic + holder should be similar to the current design so we may use the same suspension wires (I believe they are a different thickness than that used for the SOS).
  4. Ensure we can extract any transmitted beams without clipping.
  5. Fine pitch adjustment capablity should be yyy mrad (20mrad?).
  6. We should preserve the footprint of the existing TTs, given the space constraints in vacuum. Moreover, we should be able to use dog-clamps to fix the tower in place, so the base plate should be designed accordingly.
  7. Keep the machining requirements as simple as possible while achieving the above requirements- i.e. do we really need rounded optic holder? Why not just rectangular? Similarly for other complicated features in the current design.

Some problems with Udit's design as it stands:

  1. I noticed that the base of the TT and the center of the 2" optic are 4" separated. The SOS cage base and center of 3" optic are separated by 6". Currently, there is an adaptor piece that raises the TT height to match that of the SOS. If we are doing a re-design, shouldn't we just aim for the correct height in the first place?
  2. Udit doesn't seem to have taken into account the torque due to the optic+holder in the pitch balancing calculations he did. Since this is expected to be >> that of any rod/screw we use for fine pitch balancing, we need to factor that into the calculation.
  3. For the coarse pitch adjustment, we'd need to slide the wire clamping piece relative to the optic holding piece. Rather than do this stochastically and hope for the best, the idea was to use a threaded screw to realize this operation in a controlled way. However, Udit's design doesn't include the threaded hole.
  4. There are many complicated machining features which are un-necessary.
  7924   Tue Jan 22 09:18:50 2013 SteveUpdateTip - Tilttip tilt bases ordered

The corrected drawing base for tip tilt with coils are going to the shop. The will be back by the end of the week.

Attachment 1: TTbc.PDF
TTbc.PDF
  7925   Tue Jan 22 11:09:58 2013 SteveUpdateTip - TiltSS mirror holder ordered

Koji's design of the SS  2" mirror holder with flexure spring optic retainer  like Polaris-K1 has been ordered. We are getting just one to see it's effect on the hysteresis.

Attachment 1: D1201574_v1_Tip-Tilt_Mirror_Holder.SLDDRW
  14041   Fri Jul 6 12:12:09 2018 AnnalisaConfigurationThermal CompensationThermal compensation setup

I tried to put together a rudimentary heater setup. 

As a heating element, I used the soldering iron tip heated up to ~800°C.

To make a reflector, I used the small basket which holds the cork of champains battles (see figure 1), and I covered it with alumnum foil. Of course, it cannot be really considered as a parabolic reflector, but it's something close (see figure 2).

Then, I put a ZnSe 1 inch lens, 3.5 inch FL (borrowed from TCS lab) right after the reflector, in order to collect as much as possible the radiation and focus it onto an image (figure 3). In principle, if the heat is collimated by the reflector, the lens should focus it in a pretty small image. Finally, in order to see the image, I put a screen and a small piece of packaging sponge (because it shouldn't diffuse too much), and I tried to see the projected pattern with a thermal camera (also borrowed from Aidan). However, putting the screen in the lens focal plane didn't really give a sharp image, maybe because the reflector is not exactly parabolic and the heater not in its focus. However, light is still focused on the focal plane, although the image appears still blurred. Perahps I should find a better material (with less dispersion) to project the thermal image onto. (figure 4)

Finally, I measured the transmitted power with a broadband power meter, which resulted to be around 10mW in the focal plane. 

Attachment 1: IMG_1887.jpg
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Attachment 2: IMG_1884.jpg
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Attachment 3: IMG_1883.jpg
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Attachment 4: IR20180706_0358_labels.png
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  14043   Sat Jul 7 19:50:38 2018 AnnalisaConfigurationThermal CompensationStudy about the Thermal projection setup and its effect on the cavity

I made some simulation to study the change that the heater setup can induce on the Radius of Curvature of the ETM.

Heat pattern

First, I used a non-sequential ray tracing software (Zemax) to calculate the heat pattern. I made a CAD of the elliptical reflector and I put a radiative element inside it (similar to the rod-heater 30mm long, 3.8mm diameter that we ordered), placing it in such a way that the heater tip is as close as possible to the ellipse first focus. (figure 1)

Then, by putting a screen at the second focus of the ellipse (where we suppose to place the mirror HR surface), I could find the projected heat pattern, as shown in figure 2 and 3 (section). Notice that the scale is in INCH, even if the label says mm. As you can see, the heat pattern is pretty broad, but still enough to induce a RoC change. 

Mirror deformation

In order to compute the mirror deformation induced by this kind of pattern, I used this map produced with Zemax as absorption map in COMSOL. I considered ~1W total power absorbed by the mirror (just to have a unitary number).

The mirror temperature and deformation maps induced by this heat pattern are shown in figures 4 and 5. 

RoC change evaluation

Then I had to evaluate the RoC change. In particular, I did it by fitting the Radius of Curvature over a circle of radius:

r = w_{00} * \sqrt{n}

where w_{00} is the waist of tha Gaussian mode on the ETMY (5mm) and n is the mode order. This is a way to approximately know which is the Radius of Curvature as "seen" by each HOM, and is shown in figure 6 (the RoC of the cold mirror is set to be 57.37m). Of course, besides being very tiny, the difference in RoC strongly depends on the heat pattern.

Gouy phase variation

Considering this absorbed power, the cavity Gouy phase variation between hot and cold state is roughly 15kHz (I leave to the SURFs the details of the calculation).

Unanswered points

So the still unaswered questions are:

- which is the minimum variation we are able to resolve with our measurement

- how much heating power do we expect to be projected onto the mirror surface (I'll make another entry on that)

Attachment 1: reflector.png
reflector.png
Attachment 2: heat_pattern_-_f2.png
heat_pattern_-_f2.png
Attachment 3: heat_pattern_-_f2_-_cross_section.png
heat_pattern_-_f2_-_cross_section.png
Attachment 4: ETMtemperature.png
ETMtemperature.png
Attachment 5: ETMdeformation.png
ETMdeformation.png
Attachment 6: RoC_variation.png
RoC_variation.png
  14050   Tue Jul 10 23:44:23 2018 AnnalisaConfigurationThermal CompensationHeater setup assembly

[Annalisa, Koji]

Today both the heater and the reflector were delivered, and we set down the setup to make some first test.

The schematic is the usual: the rod heater (30mm long, 3.8 mm diameter) is set inside the elliptical reflector, as close as possible to the first focus. In the second focus we put the power meter in order to measure the radiated power. The broadband power meter wavelength calibration has been set at 4µm: indeed, the heater emits all over the spectrum with the Black Body radiation distribution, and the broadband power meter measures all of them, but only starting from 4µm they will be actually absorbed my the mirror, that's why that calibration was chosen.

We measured the cold resistance of the heater, and it was about 3.5 Ohm. The heater was powered with the BK precision DC power supply 1735, and we took measurements at different input current.

Current [A] Voltage [V] Measured radiated power [mW] Resistance [Ohm]
0.5 2.2 20 4.4
0.8 6 120 7.5
1 11 400 11
1.2 18 970 15

We also aimed at measuring the heater temperature at each step, but the Fluke thermal camera is sensitive up to 300°C and also the FLIR seems to have a very limited temperature range (150°C?). We thought about using a thermocouple, but we tested its response and it seems definitely too slow. 

Some pictures of the setup are shown in figures 1 and 6.

Then we put an absorbing screen in the suspension mount to see the heat pattern, in such a way to get an idea of the heat spot position and size on the ETMY. (figure 2)

The projected pattern is shown in figures 3-4-5

The optimal position of the heater which minimizes the heat beam spot seems when the heater inserted by 2/3 in the reflector (1/3 out). However, this is just a qualitative evaluation.

Finally, two more pictures showing the DB connector on the flange and the in-vacuum cables.

Some more considerations about in-vacuum cabling to come.

Steve: how are you going to protect the magnets ?

Attachment 1: IMG_1992.jpg
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Attachment 2: IMG_2002.jpg
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Attachment 3: IR20180710_0364a.png
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Attachment 4: IR20180710_0368.png
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Attachment 5: IR20180710_0360.png
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Attachment 6: IMG_1993.jpg
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Attachment 7: IMG_5322.JPG
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Attachment 8: IMG_5321.JPG
IMG_5321.JPG
  14071   Fri Jul 13 23:39:46 2018 AnnalisaConfigurationThermal CompensationThermal compensation setup - power supply

[Annalisa, Rana]

In order to power the heater setup to be installed in the ETMY chamber, we took the Sorensen DSC33-33E power supply from the Xend rack which was supposed to power the heater for the seismometer setup.

We modified the J3 connector behind in such a way to allow a remote control (unsoldered pins 9 and 8). 

Now pins 9 and 12 need to be connected to a BNC cable running to the EPICS.


RXA update: the Sorensen's have the capability to be controlled by an external current source, voltage source, or resistive load. We have configured it so that 0-5V moves the output from 0-33 V. There is also the possibility to make it a current source and have the output current (rather than voltage) follow the control voltage. This might be useful since out heater resistance is changing with temperature.

Attachment 1: IMG_2012.jpg
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Attachment 2: IMG_2013.jpg
IMG_2013.jpg
Attachment 3: 20180713_213818.jpg
20180713_213818.jpg
  14078   Tue Jul 17 17:37:46 2018 Annalisa, TerraConfigurationThermal CompensationHeaters installation

Summary

We installed two heaters setup on the ETMY bench in order to try inducing some radius of curvature change and therefore HOMs frequency shift.

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

We installed two heaters setup.

Elliptic reflector setup (H1): heater put in the focus of the elliptical reflector: this will make a heat pattern as descirbed in the elogs #14043 and #14050. 

 

Lenses setup (H2): heater put in a cylndrical reflector (made up with aluminum foil) 1'' diameter, and 2 ZnSe lenses telescope, composed by a 1.5'' and a 1'' diameter respectively, both 3.5'' focal length. The telescope is designed in such a way to focus the heat map on the mirror HR surface. For this latter the schematic was supposed to be the following: 

This setup will project on the mirror a heat pattern like this:

which is very convenient if we want to see a different radius of curvature for different HOMs. However, the power that we are supposed to have absorbed by the mirror with this setup is very low (order of 40-ish mW with 18V, 1.2A) which is probably not enough to see an effect. Moreover, mostly for space reasons (post base too big), the distances were not fully kept, and we ended up with the following setup:

In this configuration we won't probably have a perfect focusing of the heat pattern on the mirror.

In vacuum connections

See Koji's elog #14077 for the final pin connection details. In summary, in vacuum the pins are:

13 to 8 --> cable bunch 0

7 to 2 --> cable bunch 2

25 to 20 --> cable bunch 1

19 to 14 --> cable bunch 3

where Elliptic reflector setup (H1) is connected to cables 0 and 1, and the lenses setup is connected to cables 2 and 3.

Installed setup

This is the installed setup as seen from above:

Attachment 5: IMG_5380.JPG
IMG_5380.JPG
  14086   Thu Jul 19 04:44:09 2018 Annalisa, TerraSummaryThermal Compensationfrequency shift observed with heating!

Annalisa, Gautum, Koji, Terra

Summary: with the reflector setup, we measured a frequency shift of the first and second order modes! First looks of shifts show 1st HOM shift ~-10 kHz, 2nd HOM shift ~-18 kHz (carrier ~4 kHz). We saw no shift with the cylinder/lenses set up.

- - - - -

Tonight we modified the cavity scan setup: the LO is provided by the Marconi which, at the same time, is also used to scan the AUX laser frequency instead of the Agilent. In order to get rid of the free running noise between Marconi and Agilent, the Marconi frequency was scanned and, point by point, the Agilent center frequency was changed accordingly. In order to speed up the process, the whole procedure was automated. The script is called AGfast.py and can be found in /users/annalisa/postVent.

One thing that helped in improving the data quality of the phase information was to set the Agilent IF bandwidth @1kHz. Not yet clear why, but it was better than having a lower bandwidth. To be further investigated.

With this setup, we made some coarse scan of the full FSR and then we "zoomed" around the main peaks in order to increase the resolution and get a more precise information about the peak frequency.

Here are the frequency ranges that we scanned:

  • carrier - central frequency: 31.73MHz; range: [31.68MHz - 31.78MHz]
  • HOM1 - central frequency: 32.88MHz; range: [32.84MHz - 32.93MHz]
  • HOM2 - central frequency: 34.03MHz; range: [33.95MHz - 34.06MHz]
  • HOM3 - central frequency: 35.18MHz; range: [35.09MHz - 35.25MHz]

We powered the heater of the lenses setup @4:55 am at 14.4V and 0.9A. Then we slightly increased the power @5:05am and the final "hot state" configuration is with heater powered at 16V and 0.9A.

With this setup we couldn't see any frequency shift

Then, at around 6:30 am we turned on the reflector setup and we measured a frequency shift of the first and second order modes. First scans show 1st HOM shift ~10 kHz, 2nd HOM shift ~18 kHz. First attachment shows carrier hot/cold, second attachment shows HOM2 hot/cold. We started to get plauged by high seismic noise. Heaters turned off at 7:45 am. Lots of scans and actual analysis to go.


gautam: about the questionable plotting -

  • 10 faint (alpha~0.3) lines are individual measurements with the reflector doing its heating. (AG4395A, 0 span, single frequency measurements plotted together).
  • charcoal line, labelled mean, is the mean of the 10 above lines.
  • bright green ("Reference") is the mean of a coarse scan (cold ETM) overlaid for comparison. 
  • "cold" - self explanatory.

My personal favourite plot is Attachment #3, which is a 5 MHz scan (cold) to identify positions of the various peaks. The power of including phase information in the analysis is clear. The second FSR on the right edge of the plot is not as prominent as the first is because the arm transmission was degrading throughout the measurement. For future measurements, we should consider locking the IMC length to the arm cavity - this would eliminate such alignment drifts, and maybe also make the PLL control signal RMS smaller. 

Attachment 1: scanning_fine_2018-07-19-07-32-08_parsed.pdf
scanning_fine_2018-07-19-07-32-08_parsed.pdf
Attachment 2: scanning_fine_2018-07-19-06-57-47_parsed.pdf
scanning_fine_2018-07-19-06-57-47_parsed.pdf
Attachment 3: Yscan_scanning_parsed_2am.txt.pdf
Yscan_scanning_parsed_2am.txt.pdf
  14094   Sat Jul 21 01:06:49 2018 gautamSummaryThermal CompensationY arm locking

I implemented this today. For now, the LSC output matrix is set to actuate on MC2 for Y arm locking. As expected, the transmission was much more stable, and the PLL control signal RMS was also reduced by factor of ~3. MC2 control signal does pick up a large (~2000 cts) DC component over a few hours, so we need to relieve this periodically.

Now that we have a workable ASS for the Y arm as well, we should be able to have more confidence in returning to the same beam spot position on the ETM and staying there during a scan using this technique.

The main improvement to be trialled next in the scanning is to improve the speed of scanning. As things stand, my script takes ~2.5 seconds per datapoint. If we can cut this in half, that'd be huge. On Wednesday night, we were extraordinarily lucky to avoid MC3 glitching, EPICS/slow machine failures, and GPIB freezes. Today, the latter reared its head. Fortunately, since I'm dumping data to file for each datapoint, this means we at least have data till the GPIB freeze.

Quote:

For future measurements, we should consider locking the IMC length to the arm cavity - this would eliminate such alignment drifts, and maybe also make the PLL control signal RMS smaller. 


Not related to this work: Terra, Sandrine, Keerthana and I cleaned up the lab a bit today, and made better cable labels. Aaron and I have to clean up the OMC area a bit. Huge thanks to Steve for taking care of our mess elsewhere in the lab!

  14096   Sat Jul 21 14:03:19 2018 KojiSummaryThermal CompensationY arm locking

Ah. With MC2 feedback, we have about 3 times smaller "optical gain" for the ASS A2L. We have same dither, same actuator, but we need only 1/3 actuation of the MC2 compared to the ETMY case.
We had to reduce the ASS spot servo from 1 to 0.3 to make is stable, so this means that the ASS is really merginally stable.

  14103   Wed Jul 25 14:45:59 2018 SandrineSummaryThermal CompensationETM Y Table AUX read out

Attached is a photo of the set up of the ETM Y table showing the AUX read out set up. 

Currently, the flip mount sends the AUX to the PDA255. Terra inserted a razor blade so the PDA255 will witness more HOMs. The laser is also sent to the regular PD and the CCD.

Attachment 1: EY_table_.JPG
EY_table_.JPG
  14105   Thu Jul 26 01:52:01 2018 terraUpdateThermal Compensationheater work update

Just a quick update: over the past few days we've taken (at least) 5 scans around each peak [carrier - HOM3] at 9.4V/0.8A, 4 scans around [carrier - HOM5] at 12V/0.9A hot state with the reflector setup. We also have (at least) 5 scans of carrier - HOM5 in cold state. I attach a rough overview of the peak magnitude shifts in the first attachment. Analysis ongoing. All data stored in annalisa/postVent/{date}

Initial shifts just based on rought peak placement in the meantime:

            [9.4V/0.8A]   [12V/0.9A]

HOM1    10 kHz         20 kHz

HOM2    18 kHz         28 kHz

HOM3     30 kHz        40 kHz

HOM4     N/A             26 kHz

HOM5     N/A             35 kHz

I also attach the heating thermal transient from today (12V/0.9A) as seen by the opLevs. We see a shorter time constant for pitch, longer for yaw, preceeded by a dip in yaw. Similar behavior yesterday for slightly less heating, though less pronounced pre-dip. The heater is offcentered on the optic horizontally; likely this is part of the induced yaw. The spikey stuff i removed is from people walking around inside during the transient.

I've left the heater and LSC off for the night. Heater off at 2:07 am local time.

Please don't touch the oplevs; we're taking a cool down measurement.

Attachment 1: OpLev_thermal_drift.pdf
OpLev_thermal_drift.pdf
Attachment 2: hotColdAll.pdf
hotColdAll.pdf
  14109   Fri Jul 27 17:16:14 2018 SandrineUpdateThermal CompensationCopied working scripts for mode spectroscopy into new directory (modeSpec)

The scripts: AGfast.py, make HDF5.py, plotSpec_marconi.py, and SandrineFitv3.py were copied into the new directory modeSpec.

The path is: /opt/rtcds/caltech/c1/scripts/modeSpec

These scripts can still be found under Annalisa's directory under postVent.

  14110   Sat Jul 28 00:45:11 2018 terra, sandrineSummaryThermal CompensationHeater measurements overview

[Sandrine, Koji, Terra]

Summary: We completed multiple scans at different heating powers for the reflector set up, observing unique HOM peak shifts of tens of kHz. We also observed HOM5 shifts with the cylinder set up. Initial Lorentzian fittings of the magnitude give tens of Hz resolution. I summarize the main week's work below. 

Set-up

Heater set-up is described in several previous elogs, but attachments #1 and #2 show the full heater set-up and wiring/pinouts in and out of vacuum, since we're all intimately aware of how confusing in-vacuum pinouts can be. We are not using the Sorenson power supply (as described in 14071); we just have the BKPrecision power supply 1735 sitting next to the ETMY rack and are manually going out to turn on/off. 

We've continued to use the scan setup described in elog 14086, which is run using /users/annalisa/postVent/AGfast.py. Step by step notes for setting up the scan, running the scans, and processing the scans are attached in notes.txt.

Inducing/witnessing HOMs

The aux input beam was already clipped and on wednesday (after Trans was centered, 14093) we also clipped the output aux beam with razor blade (angled vertically and horizontally, elog 14103) before PDA255; we clipped ~1/3 of the output beam. Attachment #3 shows before and after clipping output, where orange 'cold' == unclipped, black 'mean' == clipped (all in cold state). Up to HOM5 is visible. 

Measurements

Below is a summary of the available scan data. We also have cold (0A) scans CAR-HOM5 and full FSR scans for most configurations. 

Elliptic Reflector
current[A] voltage[V] power[W] scans
0.4 2 0.8 CAR-HOM3(x1)
0.5 3.4 1.7 CAR-HOM3(x1)
0.6 5 3.0 CAR-HOM3(x1)
0.8 9.4(9.7) 7.5(7.8) CAR-HOM5(>x5)
0.9 12 10.8 CAR-HOM5(x4)
1.09 17 18.5 CAR-HOM3

 

 

 

 

 

 

 

Cylinder + Lenses
current[A] voltage[V] power[W] scans
0.9 15 13.5 CAR-HOM5(odds x4)

We tried the cylinder set-up again tonight for the first time since inital try and can see shifts of HOM5 - see attachment #5; we haven't looked in detail yet, but it looks like odd modes are more effected, suggesting the ring heat pattern is off centered from the beam axis. 

Scan data is saved in the following format: users/annalisa/postVent/scandata/{reflector,cylinder}/{parsed,unparsed}/{CAR,HOM1,HOM2,HOM3,HOM4,HOM5}{_datetime}{_parsed,_unparsed}.{txt,pdf}

Minimum heating

On 7/26 we increased the power to the elliptical reflector heater in steps to find the minimum heater power required to see frequency shifts with our measurement setup. Lowest we can resolve is a shift in HOM3 with 1.7W (0.5A/3.4V). According to Annalisa's measurements in elog 14050, this would be something like 30-60 mW radiated power hitting the test mass. We only looked at CAR - HOM3 for this investigation; data for scans at 0.4A, 0.5A, 0.6A is available as indicated above.

Lorentizian Fitting

The Lorentzian fitting was done using the equation a + b / sqrt(1+((x-c)/d*2), where a = constant background, b = peak height above background, c = peak frequency, d = full width at half max. 

The fitting is still being edited and optimized. We will crop the data to zoom in around the peak more.

The Lorentzian fit of the magnitude shows ~10Hz of resolution. (See attachment 6 for the carrier at 8A and attachment 7 for HOM 1 at 9A)

We're working on fitting the full complex data.

 

 

Attachment 1: heater_setup.jpg
heater_setup.jpg
Attachment 2: heater_wiring.jpg
heater_wiring.jpg
Attachment 3: notes.txt
Notes for running scans:
1. when first turning on Agilent, set initial stuff
    > cd /users/annalisa/postVent/20180718
    > AGmeasure TFAG4395Atemplate.yml
2. tweak arm alignment and offset PLL
    > sitemap (then IFO --> ALIGN and also PSL --> AUX)
    > to increase 
3. make sure X-arm is misagligned (hit '! Misalign' button for ITMX, ETMX) 
3. run scan
    > python AGfast.py startfreq stopfreq points
... 36 more lines ...
Attachment 4: FSR_clipped.pdf
FSR_clipped.pdf
Attachment 5: cylinderHOM5.pdf
cylinderHOM5.pdf
Attachment 6: pt8A_CAR.pdf
pt8A_CAR.pdf
Attachment 7: pt9A_HOM1.pdf
pt9A_HOM1.pdf
  14405   Fri Jan 18 15:34:37 2019 gautamUpdateThermal CompensationElliptical reflector part number

Nobody documented this, but here is the part number with mechanical drawings of the elliptical reflector installed at EY: Optiforms E180. Heater is from Induceramics, but I can't find the exact part which matches the dimensions of the heater we have (diameter = 3.8mm, length = 30mm), perhaps it's a custom part?

The geometry dictates that if we want the heater to be at one focus and the ETM to be at the other, the separation has to be 7.1 inches. It certainly wasn't arranged this way before. It seems unrealistic to do this without clipping the main beam, I propose we leave sufficient clearane between the main beam and the reflector, and accept the reduced heating efficiency. 

Thanks to Steve for digging this up from his secret stash.

  14545   Mon Apr 15 22:55:34 2019 gautamFrogsThermal CompensationLab thermostat adjusted

It is feeling cold in the office area. According to the digital wall clock near the coffee machine, it is 19C. Rana bumped the thermostat setpoint up by 2F (from 75F to 77F). We need to setup long-term monitoring.

  224   Thu Jan 3 12:38:49 2008 robBureaucracyTMISore throat

Quote:

I did not feel anything wrong yesterday, but unfortunately I have a very much sore throat today. I need to drink warm milk with honey and rinse my throat often today. So far I do not have other illness symptomes (no fever), so I hope that this small disease will not last for a long time, but I feel that it is better for me to cure my sore throat today at home (and probably it is safer for others in 40-m).

I took yesterday the book "Digital Signal Processing", so I have it for reading at home.

Hope to see you tomorrow.


I've added a new category--TMI--for entries along these lines.
  229   Wed Jan 9 20:29:47 2008 DmassAoGTMICoffee Carafe
If you have been using the coffee machine in the 40m, you may have noticed small brown flecks in your coffee mug. The carafe in the 40m has accumulated a layer of what is presumed to be old dried up coffee. When a small amount of water is swirled around in the bottom, flecks of the brown layer come off. Pictures below are of the inside of the carafe.

But does it provide adequate protection from 1064 light?
Attachment 1: DSC_0363.JPG
DSC_0363.JPG
Attachment 2: DSC_0365.JPG
DSC_0365.JPG
Attachment 3: DSC_0368.JPG
DSC_0368.JPG
  279   Mon Jan 28 12:42:48 2008 DmassBureaucracyTMICoffee
There is tea in the coffee carafe @ the 40m. It is sitting as though it were fresh coffee. There is also nothing on the post it.
  341   Tue Feb 26 20:24:04 2008 AndreySummaryTMISorrow
As for that plot of three-dimensional surface, I indeed was wrong with the axis "Q_ETMX-Q_ITMX" (I put there wrong string "Q_ITMX-Q_ETMX"). On Friday plot there were values 10^(-12) on the z-axis, and that should be really meters, but the point that as I realized on Monday, I have never calibrated experimental measurement results from counts to meters , that's why it is this difference between 10^(-6) and 10^(-12). I still did not find the way to compare experim. and theoretical plots, because even if I leave "counts" on both plots, so that I have scale 10^(-6) on both plots, then the change in theoretical plot is just 0.02*10^(-6) for the range of Q-factors change, while the change in experimental measurements is an order of magnitude more 0.4*10^(-6), so the surface for theretical plot would be almost flat in the same axes as experimental results.
  2887   Thu May 6 17:47:01 2010 Alberto, kiwamu, Jc The 3rd (aka The Drigg)OmnistructureTMIMinutes from the Lab Organization Commitee meeting

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

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

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

Enjoy!

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

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

Quote:

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

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

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

Enjoy!

 

  7695   Fri Nov 9 18:28:23 2012 CharlesUpdateSummary PagesCalendar

The calendar tab now displays calendars with weeks that run from Sunday to Saturday (as opposed to Monday to Sunday). However, the frame on the left hand side of the main page still has 'incorrect' calendars.

 

  8003   Tue Feb 5 12:08:43 2013 Max HortonUpdateSummary PagesUpdating summary pages

Getting started:  Worked on understanding the functionality of summary_page.py.  The problem with the code is that it was written in one 8000 line python script, with sparse documentation.  This makes it difficult to understand and tedious to edit, because it's hard to tell what the precise order of execution is without tracing through the code line by line.  In other words, it's difficult to get an overview of what the code generally does, without literally reading all of it.  I commented several functions / added docstrings to improve clarity and start fixing this problem.

Crontab:  I believe I may have discovered the cause of the 6PM stop on data processing.  I am told that the script that runs the summary_pages.py is called every 6 hours.  I believe that at midnight, the script is processing the next day's data (which is essentially empty) and thus not updating the data from 6PM to midnight for any of the days.

Git:  Finally, created git repository called public_html/__max_40m-summary_testing to use for testing the functionality of my changes to the code (without risking crashing the summary_pages).

  8055   Mon Feb 11 13:07:17 2013 Max HortonUpdateSummary PagesFixed A Calendar Bug

Understanding the Code:  Documented more functions in summary_pages.py.  Since it is very difficult and slow to understand what is going on, it might be best to just start trying to factor out the code into multiple files, and understand how the code works from there.

Crontab:  Started learning how the program is called by cron / what cron is, so that I can fix the problem that forces data to only be displayed up until 6PM.

Calendars:  One of the problems with the page is that the calendars on the left column didn't have any of the months of 2013 in them.

I identified the incorrect block of code as:

Original Code:
  # loop over months
  while t < e:
     if t.month < startday.month or t >= endday:
       ptable[t.year].append(str)
    else:
      ptable[t.year].append(calendar_link(t, firstweekday, tab=tab, run=run))

    # increment by month
    # Move forward day by day, until a new month is reached.
    m = t.month
    while t.month == m:
      t = t + d

    # Ensure that y still represents the current year.
    if t.year > y:
      y = t.year
      ptable[y] = []

The problem is that the months between the startday and endday aren't being treated properly.

Modified Code:
  # loop over months
  while t < e:
    if (t.month < startday.month and t.year <= startday.year) or t >= endday:
      ptable[t.year].append(str)
    else:
      ptable[t.year].append(calendar_link(t, firstweekday, tab=tab, run=run))

    # increment by month
    # Move forward day by day, until a new month is reached.
    m = t.month
    while t.month == m:
      t = t + d

    # Ensure that y still represents the current year.
    if t.year > y:
      y = t.year
      ptable[y] = []


After this change, the calendars display the year of 2013, as desired.

  8098   Mon Feb 18 11:54:15 2013 Max HortonUpdateSummary PagesTiming Issues and Calendars

Crontab: The bug of data only plotting until 5PM is being investigated.  The crontab's final call to the summary page generator was at 5PM.  This means that the data plots were not being generated after 5PM, so clearly they never contained data from after 5PM.  In fact, the original crontab reads:

0 11,5,11,17 * * * /users/public_html/40m-summary/bin/c1_summary_page.sh 2>&1

I'm not exactly sure what inspired these entries.  The 11,5,11,17 entries are supposed to be the hours at which the program is run.  Why is it run twice at 11?  I assume it was just a typo or something.

The final call time was changed to 11:59PM in an attempt to plot the entire day's data, but this method didn't appear to work because the program would still be running past midnight, which was apparently inhibiting its functionality (most likely, the day change was affecting how the data is fetched).  The best solution is probably to just wait until the next day, then call the summary page generator on the previous day's data.  This will be implemented soon.

Calendars: Although the calendar tabs on the left side of the page were fixed, the calendars displayed at: https://nodus.ligo.caltech.edu:30889/40m-summary/calendar/ appear to still have squished together text.  The calendar is being fetched from https://nodus.ligo.caltech.edu:30889/40m-summary/calendar/calendar.html and displayed in the page.  This error is peculiar because the URL from which the calendar is being fetched does NOT have squished together text, but the resulting calendar at 40m-summary/calendar/ will not display spaces between the text.  This issue is still being investigated.

ELOG V3.1.3-