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ID Date Author Typedown Category Subject
  14020   Tue Jun 26 17:20:33 2018 JonConfigurationCamerasLLO Python Camera Software is Working

Thanks to a discussion yesterday with Joe Betzweiser, I was able to identify and fix the remaining problem with the LLO GigE camera software. It is working now, currently only on rossa, but can be set up on all the machines. I've started a wiki page with documentation and usage instructions here:

https://wiki-40m.ligo.caltech.edu/Electronics/GigE_Cameras

This page is also linked from the main 40m wiki page under "Electronics."

This software has the ability to both stream live camera feeds and to record feeds as .avi files. It is described more on the wiki page.

  14026   Wed Jun 27 19:37:16 2018 KojiConfigurationComputersNew NAT router installed

[Larry, Koji]

We replaced the NAT router between martian and the campus net. We have the administrative web page available for the NAT router, but it is accessible from inside (=martian) as expected.

We changed the IP address registration of nodus for the internet so that the packets to nodus is directed to the NAT router. Then the NAT router forwards the packets to actual nodus only for the allowed ports. Because of this change of the IP we had a few confusions. First of all, martian net, which relies on chiara for DNS resolution. The 40m wifi router seemed to have internal DNS cache and required to reboot to make the IP change effective.

The WAN side cable of nodus was removed.

We needed to run "sudo rndc flush" to force chiara's bind9 to refresh the cache. We also needed to restart httpd ("sudo systemctl restart httpd") on nodus to make the port 8081 work properly. 

So far, ssh (22), web services (30889), and elog (8081, 8080) were tested. We also need to test megatron NDS port forwarding and rsync for nodus, too.

Finally I turned off the firewall rules of shorewall on nodus as it is no longer necessary.

More details are found on the wiki page. https://wiki-40m.ligo.caltech.edu/FirewallSetting

Attachment 1: P_20180627_193357.jpg
P_20180627_193357.jpg
  14033   Fri Jun 29 18:16:32 2018 JonConfigurationPSLChanges to AUX Optical Layout on PSL Table

In order to use the 0th-order deflection beam from the AOM for cavity mode scans, I've coaligned this beam to the existing mode-matching/launch optics set up for the 1st-order beam.

Instead of being dumped, the 0th-order beam is now steered by two 45-degree mirrors into the existing beam path. The second mirror is on a flip mount so that we can quickly switch between 0th-order/1st-order injections. None of the existing optics were touched, so the 1st-order beam alignment should still be undisturbed.

Currently the 0th-order beam is being injected into the IFO. After attenuating so as to not exceed 100 mW incident on the fiber, approximately 50 mW of power reaches the AS table. That coupling efficiency is similar to what we have with the 1st-order beam. With the Y-arm cavity locked and the AUX PLL locked at RF offset = 47.60 MHz (an Y-arm FSR), I observed a -50 dBm beat note at Y-end transmission.

Attachment 1: PSL_AUX_SETUP_CHANGE.pdf
PSL_AUX_SETUP_CHANGE.pdf
  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 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 6: IMG_1993.jpg
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Attachment 8: IMG_5321.JPG
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  14062   Fri Jul 13 00:15:13 2018 Annalisa, TerraConfigurationAUXY arm cavity scan

[Annalisa, Terra, Koji, Gautam]

Summary: We find a configuration for arm scans which significantly reduces phase noise. We run several arm scans and we were able to resolve several HOM peaks; analysis to come.

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

As first, we made a measurement with the already established setup and, as Jon already pointed out, we found lots of phase noise. We hypothesized that it could either come from the PLL or from the motion of the optics between the AUX injection point (AS port) and the Y arm. 

  • We first characterized the PLL loop phase noise by comparing the beat signal against the Agilent reference signal, and we found that the beat had lots of phase noise with respect to the reference. Decreasing the PLL gain, we got rid of the phase noise in the beat signal.
  • Next, for the optical path length induced phase noise, we took the transfer function between TransMon and REFL signal rather than TransMon and Agilent reference signal. This takes advatage of the fact that the TransMon and REFL both see optical path length phase noise, which therefore gets canceled out in the transfer function. 

In this configuration, we were able to do arm scans where the phase variation at each peak was pretty clear and well defined. We took several 10MHz scan, we also zoomed around some specific HOM peak, and we were able to resolve some frequency split. 

We add some pictures of the setup and of the scan.

The data are saved in users/OLD/annalisa/Yscans. More analysis and plots will follow tomorrow. 

Attachment 1: IMG_6492.JPG
IMG_6492.JPG
Attachment 2: IMG_6494.JPG
IMG_6494.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
IMG_2012.jpg
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
  14091   Fri Jul 20 18:30:47 2018 JonConfigurationAUXRecommend to install AUX PZT driver

I recently realized that the PLL is only using about 20% of the available actuation range of the AUX PZT. The +/-10 V control signal from the LB1005 is being directly inputted into the fast AUX PZT channel, which has an input range of +/-50 V.

I recommend to install a PZT driver (amplifier) between the controller and laser to use the full available actuator range. For cavity scans, this will increase the available sweep range from +/-50 MHz to +/-250MHz. This has a unique advantage even if slow temperature feedback is also implemented. To sample faster than the timescale of most of the angular noise,  scans generally need to be made with a total sweep time <1 sec. This is faster than the PLL offset can be offloaded via the slow temperature control, so the only way to scan more than 100 MHz in one measurement is with a larger dynamic range.

  14104   Wed Jul 25 22:46:15 2018 gautamConfigurationComputersNDS access from outside

After this work, I've been having some trouble getting data with Python NDS. Eventually, I figured out that the nds connection request has to be pointed at '131.215.115.200' (the address of the NAT router which faces the outside world), port 31200 (it used to work with 'nds40.ligo.caltech.edu' or '131.215.115.189'). So the following snippet in python allows a connection to be opened. Offline access of frame data via NDS2 now seems possible.

import nds2
conn = nds2.connection('131.215.115.200',31200)
Quote:
 

So far, ssh (22), web services (30889), and elog (8081, 8080) were tested. We also need to test megatron NDS port forwarding and rsync for nodus, too.Finally I turned off the firewall rules of shorewall on nodus as it is no longer necessary.

  14153   Fri Aug 10 11:29:39 2018 aaronConfigurationUpgradeParts list for BHD

I've started putting together a list of things we'll need to buy to do BHD readout. I'm still messing around with more detailed optics layouts, but wanted to get a list started here so people can let me know if I'm missing any big, obvious categories of goods.

My current plan makes minimal changes to the signal path going to the OMC, and tries to just get the LO beam into the OMC with minimal optics. I'm not thinking of any of the optics as suspended, and it requires several reflections of the LO beam, so probably this is not an excellent configuration, but it's a start for getting the parts list:

  1. My current thought is to use the MC reflection, the beam that heads from MC1 to MCR1, as the LO beam
    1. From MCR1, send the LO to a BS that directs it into an MMT, oriented along x (and lets us keep the MC refl PO)
    2. After the two MMT optics, the beam will be traveling along -x, and can be directed to a mirror that sends it towards -y to two steering mirrors that send it along -x then +x near the top of the table (perpendicular to the signal MMT.
    3. Then, send it to a PBS, which replaces the mirror directly after the signal MMT. This is where it combines 
  2. Beam is then sent to the steering mirrors to bring it into the OMC
  3. In parallel, the signal beam is going through the same path it has now, including the pickoff beam, with the one change that we need a HWP somewhere before the PBS, and the PBS replaces the mirror directly after the MMT (and needs to move a bit closer to have the beam properly directed)

I started making a layout of this scheme, but it's probably not going to work so I'm going to make a quick layout of this more major modification instead:

  1. Both the MCR beam and the AS beam come in about parallel. Send each to a PO mirror.
  2. The PO mirror directs both beams into parallel MMT aligned along x
  3. From the MMT, each is directed to a pair of steering mirrors located where the OMC MMT is located now
  4. From the steering mirrors go to the PBS that combines the signal and LO
  5. Then to two more steering mirrors to get into the OMC, which may be moved towards +x
  6. From the OMC go to the BHD PBS

What we need

Optics

  • HWP for just before the LO combines with the signal
  • HWP for just before the signal combines with the LO (is this necessary?)
  • PBS to replace OM5 (combines the LO and the signal)
  • Two MMT optics
  • Two piezo-driven TT optics for steering the LO to the PBS
  • One additional non-piezo optic for between the LOMMT and the LO-TTs
  • One additional BS to get the LO into the MMT (and to let us still have the PO)
  • -1 optic—we pick up one mirror that we replace with the PBS

Optomechanics

  • 2x HWP mounts
  • 1x PBS mount
  • 2x mounts for piezo-driven TT
  • 2x MMT optic mounts—I didn’t take a close enough look at these during the vent to know what we need here
  • 2x mounts for ordinary optics
  • 9x clamps for optics mounts (maybe fewer if some are on blocks)
  • 9x posts for optics mounts

Electronics

  • Additional TT driver
  • HV supply for the new TTs
  • Are the HWP actively controlled? We might need something to drive those?
  • Do we have enough DAC/ADC channels?

Questions

These are mostly just miscellaneous

  1. What of these optics need to be suspended? If we need suspensions on all of the LO optics, including the MMT, I’m not sure we’re going to be able to fit all of this on the table as I envision it…..
  2. What if anything can we put out of vacuum (HWP for example)?
  3. Do we actually need two MMT?
  14154   Fri Aug 10 16:43:50 2018 gautamConfigurationUpgradeParts list for BHD

Can we use the leakage beam from MMT2 on the OMC table as the LO beam? I can't find the spec for this optic, but the leakage beam was clearly visible on an IR card even with the IMC locked with 100 mW input power so presumably there's enough light there, and this is a cavity transmission beam which presumably has some HOM content filtered out.

Quote:

My current thought is to use the MC reflection, the beam that heads from MC1 to MCR1, as the LO beam

  14155   Sun Aug 12 10:59:34 2018 aaronConfigurationUpgradeParts list for BHD

That seems fine, I wasn't thinking of that beam. in that case could we just have a PBS directly behind MMT2 and send both beams to the same OMMT?

Alternatively we can move OM5 and the beam path OMPO-OMMTSM towards -y, then put the LO-OMMT parallel to the existing OMMT but displaced in +x... we'd have to move the existing OMC and BHD towards +x as well. 

Quote:

Can we use the leakage beam from MMT2 on the OMC table as the LO beam? I can't find the spec for this optic, but the leakage beam was clearly visible on an IR card even with the IMC locked with 100 mW input power so presumably there's enough light there, and this is a cavity transmission beam which presumably has some HOM content filtered out.

  14158   Mon Aug 13 17:20:07 2018 aaronConfigurationUpgradeParts list for BHD

I've attached the diagram of what I mean.

There are a couple caveats and changes that would have to be made that are not included in this diagram, because they would be made on different tables.

  1. I moved MMT2, which means the other MMT optics would have to be adjusted to accomodate this. I checked out the configuration on the BS table and this seems doable with a small rotation of MMT1 and maybe PJ2.
  2. I don't know the best way to get the OMC REFL beam out... thoughts?
  3. This diagram is kind of crappy after my edits, someone should tell me how to avoid collapsing all layers when I open these layout diagrams in inkscape, because I ended up editing the layout in Acrobat instead, where the lack of object grouping caused a bunch of the optics to lose one or two lines along the way.
  4. I didn't include all beam paths explicitly but can if this looks like a good configuration.
  5. The optic that picks off the transmission through MMT2 will need to move a bit, but there was a clamp in the way; this should be a minor change.
  6. The optic just before the OMC needs to be moved up a bit.
  7. The optic after the signal OMMT should be changed to a PBS and translated a bit; this is where the LO and signal beams will combine

Gautam also had some questions about the BHD/OMC timeline and plan. I feel somewhat on shaky ground with the answers, but figured I'd post them so I can be corrected once and for all.

  1. Is the plan really to use the current OMC setup to make a homodyne measurement? 
    1. I'm not sure where on the timeline the new OMC and BHD switchover are relative to each other. I have been imagining doing the swap to BHD before having a new OMC.
  2. I thought the current OMC resurrection plan was to do DC readout and not homodyne?
    1. I think the OMC resurrection plan is leading to DC readout, but when we switch over to BHD we'll be able to operate at the dark fringe. Is that right?
  3. Is it really possible to use our single OMC to clean both the LO and dark port beams? Isn't this the whole raging debate for A+?
    1. My understanding is yes, with the LO and DP in orthogonal polarizations. It's not clear to me why we expect to be able to do this while there is a debate for A+, perhaps our requirements are weaker. It is something I should calculate, I'll talk to Koji.
  4. A layout diagram would be really useful.
    1. Attached now.
  5. Where in the priority list does this come in?
    1. I am a leaf in the wind. I think this comes well after we have the OMC resurrected, we just want to get a sense for what parts we need so we can order them before the fiscal year closes.
Quote:

That seems fine, I wasn't thinking of that beam. in that case could we just have a PBS directly behind MMT2 and send both beams to the same OMMT?

Alternatively we can move OM5 and the beam path OMPO-OMMTSM towards -y, then put the LO-OMMT parallel to the existing OMMT but displaced in +x... we'd have to move the existing OMC and BHD towards +x as well. 

Quote:

Can we use the leakage beam from MMT2 on the OMC table as the LO beam? I can't find the spec for this optic, but the leakage beam was clearly visible on an IR card even with the IMC locked with 100 mW input power so presumably there's enough light there, and this is a cavity transmission beam which presumably has some HOM content filtered out.

 

Attachment 1: BHD_layout.pdf
BHD_layout.pdf
  14205   Fri Sep 21 09:59:09 2018 yukiConfigurationASCY end table upgrade plan

[Yuki, Gautam]

Attachments #1 is the current setup of AUX Y Green locking and it has to be improved because:

  • current efficiency of mode matching is about 50%
  • current setup doesn't separate the degrees of freedom of TEM01 with PZT mirrors (the difference of gouy phase between PZT mirrors should be around 90 deg) 
  • we want to remotely control PZT mirrors for alignment
    (Attachments #2 and #3)

About the above two: 

One of the example for improvement is just adding a new lens (f=10cm) soon after the doubling crystal. That will make mode matching better (100%) and also make separation better (85 deg) (Attachments #4 and #5). I'm checking whether we have the lens and there is space to set it. And I will measure current power of transmitted main laser in order to confirm the improvement of alignment.

About the last:

I am considering what component is needed. 

Reference:

Attachment 1: Pic_CurrentSetup_AUXYgreen.jpeg
Pic_CurrentSetup_AUXYgreen.jpeg
Attachment 2: ModeMatchingSolution_Current.pdf
ModeMatchingSolution_Current.pdf
Attachment 3: ModeMatchingSolution_Current_Magnified.pdf
ModeMatchingSolution_Current_Magnified.pdf
Attachment 4: ModeMatchingSolution_Optimized.pdf
ModeMatchingSolution_Optimized.pdf
Attachment 5: ModeMatchingSolution_Optimized_Magnified.pdf
ModeMatchingSolution_Optimized_Magnified.pdf
  14212   Sun Sep 23 19:32:23 2018 yukiConfigurationASCY end table upgrade plan

[ Yuki, Gautam ]

The setup I designed before has abrupt gouy phase shift between two steering mirrors which makes alignment much sensitive. So I designed a new one (Attached #1, #2 and #3). It improves the slope of gouy phase and the difference between steering mirrors is about 100 deg. To install this, we need new lenses: f=100mm, f=200mm, f=-250mm which have 532nm coating. If this setup is OK, I will order them.

There may be a problem: One lens should be put soon after dichroic mirror, but there is little room for fix it. (Attached #4, It will be put where the pedestal is.)  Tomorrow we will check this problem again.

And another problem; one steering mirror on the corner of the box is not easy to access. (Attached #5) I have to design a new seup with considering this problem.

Quote:

One of the example for improvement is just adding a new lens (f=10cm) soon after the doubling crystal. That will make mode matching better (100%) and also make separation better (85 deg) (Attachments #4 and #5). I'm checking whether we have the lens and there is space to set it. And I will measure current power of transmitted main laser in order to confirm the improvement of alignment.

 

Attachment 1: Pic_NewSetup0923_AUXYgreen.jpeg
Pic_NewSetup0923_AUXYgreen.jpeg
Attachment 2: ModeMatchingSolution_Result.pdf
ModeMatchingSolution_Result.pdf
Attachment 3: ModeMatchingSolution_Magnified_0923.jpg
ModeMatchingSolution_Magnified_0923.jpg
Attachment 4: pic0923_1.jpg
pic0923_1.jpg
Attachment 5: pic0923_2.jpg
pic0923_2.jpg
  14214   Mon Sep 24 11:09:05 2018 yukiConfigurationASCY end table upgrade plan

[ Yuki, Steve ]

With Steve's help, we checked a new lens can be set soon after dichroic mirror.

Quote:

There may be a problem: One lens should be put soon after dichroic mirror, but there is little room for fix it. (Attached #4, It will be put where the pedestal is.)  Tomorrow we will check this problem again.

Attachment 1: pic0924_1.jpg
pic0924_1.jpg
  14216   Tue Sep 25 18:08:50 2018 yukiConfigurationASCY end table upgrade plan

[ Yuki, Gautam ]

We want to remotely control steeing PZT mirrors so its driver is needed. We already have a PZT driver board (D980323-C) and the output voltage is expected to be verified to be in the range 0-100 V DC for input voltages in the range -10 to 10 V DC.
Then I checked to make sure ir perform as we expected. The input signal was supplied using voltage calibrator and the output was monitored using a multimeter. 
But it didn't perform well. Some tuning of voltage bias seemed to be needed. I will calculate its transfer function by simulation and check the performance again tommorow. And I found one solder was off so it needs fixing.  

Reference:
diagram --> elog 8932
 

Plan of Action:

  • Check PZT driver performs as we expected
  • Also check cable, high voltage, PZT mirrors, anti-imaging board
  • Obtain calibration factor of PZT mirrors using QPD
  • Measure some status value before changing setup (such as tranmitted power of green laser)
  • Revise setup after a new lens arrives
  • Align the setup and check mode-matching
  • Measure status value again and confirm it improves
  • (write programming code of making alignment control automatically)
  14218   Thu Sep 27 14:02:55 2018 yukiConfigurationASCPZT driver board verification

[ Yuki, Gautam ]

I fixed the input terminal that had been off, and made sure PZT driver board performs as we expect. 

At first I ran a simulation of the PZT driver circuit using LTspice (Attached #1 and #2). It shows that when the bias is 30V the driver performs well only with high input volatage (bigger than 3V). Then I measured the performance as following way:

  1. Applied +-15V to the board with an expansion card and 31.8V to the high voltage port which is the maximum voltage of PS280 DC power supplier C10013.
  2. Terminated input and connectd input bias to GND, then set offset to -10.4V. This value is refered as elog:40m/8832.
  3. Injected DC signal into input port using a function generator.
  4. Measured voltage at the OUT port and MON port.

The result of this is attached #3 and #4. It is consistent with simulated one. All ports performed well.

  • V(M1_PIT_OUT) = -4.86 *Vin +49.3 [V]
  • V(M1_YAW_OUT) = -4.86 *Vin +49.2 [V]
  • V(M2_PIT_OUT) = -4.85 *Vin +49.4 [V]
  • V(M2_YAW_OUT) = -4.86 *Vin +49.1 [V]
  • V(M1_PIT_MON) = -0.333 *Vin +3.40 [V]
  • V(M1_YAW_MON) = -0.333 *Vin +3.40 [V]
  • V(M2_PIT_MON) = -0.333 *Vin +3.40 [V]
  • V(M2_YAW_MON) = -0.333 *Vin +3.40 [V]

The high voltage points (100V DC) remain to be tested.

Attachment 1: PZTdriverSimulationDiagram.pdf
PZTdriverSimulationDiagram.pdf
Attachment 2: PZTdriverSimulationResult.pdf
PZTdriverSimulationResult.pdf
Attachment 3: PZTdriverPerformanceCheck_ResultOUT.pdf
PZTdriverPerformanceCheck_ResultOUT.pdf
Attachment 4: PZTdriverPerformanceCheck_ResultMON.pdf
PZTdriverPerformanceCheck_ResultMON.pdf
Attachment 5: PZTdriver.asc
Version 4
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WIRE 1408 656 1408 624
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WIRE 1712 656 1712 624
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WIRE 2016 656 2016 624
WIRE 1408 768 1408 736
WIRE 1552 768 1552 736
WIRE 1712 768 1712 736
... 193 more lines ...
  14219   Sun Sep 30 20:14:51 2018 yukiConfigurationASCQPD calibration

[ Yuki, Gautam, Steve ]

Results:
I calibrated a QPD (D1600079, V1009) and made sure it performes well. The calibration constants are as follows:

X-Axis: 584 mV/mm
Y-Axis: 588 mV/mm

Details:
The calibration of QPD is needed to calibrate steeing PZT mirrors. It was measured by moving QPD on a translation stage. The QPD was connected to its amplifier (D1700110-v1) and +-18V was supplied from DC power supplier. The amplifier has three output ports; Pitch, Yaw, and Sum. I did the calibration as follows:

  • Center beam spot on QPD using steering mirror, which was confirmed by monitored Pitch and Yaw signals that were around zero.  
  • Kept Y-axis micrometer fixed, moved X-axis micrometer and measured the outputs. 
  • Repeated the procedure for the Y-axis. 

The results are attached. The main signal was fitted with error function and I drawed a slope at zero crossing point, which is calibration factor. I determined the linear range of the QPD to be when the output was in range -50V to 50V, then corresponding displacement range is about 0.2 mm width. Using this result, the PZT mirrors will be calibrated in linear range of the QPD tomorrow. 

Comments:

  • Some X-Y coupling existed. When one axis micrometer was moved, a little signal of the other direction was also generated.
  • As Gautam proposed in the previous study, there is some hysteresis. That process would bring some errors to this result.
  • A scale of micrometer is expressed in INCH!
  • The micrometer I used was made to have 1/2 inch range, but it didn't work well and the range of X-axis was much narrower. 

Reference:
previous experiment by Gautam for X-arm: elog:40m/8873, elog:40m/8884

Attachment 1: QPDcalibrationXaxis.pdf
QPDcalibrationXaxis.pdf
Attachment 2: QPDcalibrationYaxis.pdf
QPDcalibrationYaxis.pdf
  14220   Mon Oct 1 12:03:41 2018 not yukiConfigurationASCPZT driver board verification

I assume this QPD set is a D1600079/D1600273 combo.

How much was the SUM output during the measurement? Also how much were the beam radii of this beam (from the error func fittings)?
Then the calibration [V/m] is going to be the linear/inv-linear function of the incident power and the beam radus.

You mean the linear range is +/-50mV (for a given beam), I guess.

 

  14221   Mon Oct 1 13:33:55 2018 yukiConfigurationASCQPD calibration
Quote:

I assume this QPD set is a D1600079/D1600273 combo.

How much was the SUM output during the measurement? Also how much were the beam radii of this beam (from the error func fittings)?
Then the calibration [V/m] is going to be the linear/inv-linear function of the incident power and the beam radus.

You mean the linear range is +/-50mV (for a given beam), I guess.

  • The SUM output was from -174 to -127 mV.
  • The beam radii calculated from the error func fittings was 0.47 mm.
  • Total optical path length measured by a ruler= 36 cm.
  • Beam power measured at QPD was 2.96 mW. (There are some loss mechanism in the setup.)

Then the calibration factor of the QPD is

X axis: 584 * (POWER / 2.96mW) * (0.472mm /  RADIUS) [mV/mm]
Y axis: 588 * (POWER / 2.96mW) * (0.472mm /  RADIUS) [mV/mm].

Attachment 1: Pic_QPDcalibration.jpg
Pic_QPDcalibration.jpg
  14222   Mon Oct 1 20:39:09 2018 gautamConfigurationASCc1asy

We need to set up a copy of the c1asx model (which currently runs on c1iscex), to be named c1asy, on c1iscey for the green steering PZTs. The plan discussed at the meeting last Wednesday was to rename the existing model c1tst into c1asy, and recompile it with the relevant parts copied over from c1asx. However, I suspect this will create some problems related to the "dcuid" field in the CDS params block (I ran into this issue when I tried to use the dcuid for an old model which no longer exists, called c1imc, for the c1omc model).

From what I can gather, we should be able to circumvent this problem by deleting the .par file corresponding to the c1tst model living at /opt/rtcds/caltech/c1/target/gds/param/, and rename the model to c1asy, and recompile it. But I thought I should post this here checking if anyone knows of other potential conflicts that will need to be managed before I start poking around and breaking things. Alternatively, there are plenty of cores available on c1iscey, so we could just set up a fresh c1asy model...

 
  • (write programming code of making alignment control automatically)
  14224   Tue Oct 2 18:50:53 2018 yukiConfigurationASCPZT mirror calibration

[ Yuki, Gautam ]

I calibrated PZT mirrors. The ROUGH result was attached. (Note that some errors and trivial couplings coming from inclination of QPD were not considered here. This should be revised and posted again.) 

The PZT mirrors I calibrated were:

  • A 2-inch CVI mirror (45 degree, HR and AR for 532nm)
  • A 1-inch Laseroptik mirror (45 degree, HR and AR for 532nm)

I did the calibration as follows:

  • +-15V was supplied to PZT driver circuit, +100V to PZT driver bias, and +-18V to QPD amplifier.
  • Optical path length was set to be same as that when I calibrated QPD, which is 36cm.
  • The full range of CVI mirror is 3.5mrad according to its datasheet and linear range of QPD is 0.2mm, so I set the distance between PZT mirrors and QPD to be about 6cm. (I realized it was wrong. When mirror tilts 1 deg, the angle of beam changes 2 deg. So the distance should be the half.)
  • After applying 0V to PZT driver input (at that time 50V was applied to PZT mirror), then centered beam spot on QPD using steering mirror, which was confirmed by monitored Pitch and Yaw signals of QPD that were around zero.  
  • In order to avoid hysteresis effect, I stared with an input signal of -10V. I then increased the input voltage in steps of 1V through the full range from -10V to +10V DC. The other input was kept 0V.
  • Both the X and Y coordinates were noted in the plot in order to investigate pitch-yaw coupling.

The calibration factor was

CVI-pitch: 0.089 mrad/V

CVI-yaw: 0.096 mrad/V

Laseroptic-pitch: 0.062 mrad/V

Laseroptic-yaw: 0.070 mrad/V

Comments:

  • I made sure that PZT mirrors move linearly in full input range (+-10V).
  • PZT CH1 input: Yaw, CH2: Pitch, CH3: +100V bias
  • The calibration factor of PZT mirrors [mrad/V] are not consistent with previous calibration (elog:40m/8967). I will check it again.
  • I measured the beam power in order to calibrate QPD responce with a powermeter, but it didn't have high precision. So I used SUM output of QPD to the calibration.
  • Full range of PZT mirrors looks 2 times smaller.

Reference:
Previous calibration of the same mirrors, elog:40/8967

Attachment 1: PZTM1calibrationCH2.pdf
PZTM1calibrationCH2.pdf
Attachment 2: PZTM1calibrationCH1.pdf
PZTM1calibrationCH1.pdf
Attachment 3: PZTM2calibrationCH2.pdf
PZTM2calibrationCH2.pdf
Attachment 4: PZTM2calibrationCH1.pdf
PZTM2calibrationCH1.pdf
  14226   Wed Oct 3 14:24:40 2018 yukiConfigurationASCY end table upgrade plan

Interim Procedure Report:

Purpose

The current setup of AUX Y-arm Green locking has to be improved because:

  • current efficiency of mode matching is about 50%
  • current setup doesn't separate the degrees of freedom of TEM01 with PZT mirrors (the difference of gouy phase between PZT mirrors should be around 90 deg) 
  • we want to remotely control PZT mirrors for alignment

What to do

  • Design the new setup and order optices needed (finished!)
      - As the new setup I designed, adding a new lens and slightly changing the position of optics are only needed. The new lens was arrived here.
  • Check electronics (PZT, PZT driver, high voltage, cable, anti-imaging board) (finished!)
      
    - All electronics were made sure performing well.
      - The left thing to do is making a cable. (Today's tasks)
  • Calibrate PZT mirror [mrad/V] (finished!)
      
    - The result was posted here --> elog:40m/14224.
  • Measure the status value of the current setup (power of transmitted light ...etc) (Tomorrow, --> finished!)
  • Install them in the Y-end table and align the beam (Will start from Tomorrow) (The setup has a probrem I found on 10/04)
  • Measure the status value of the new setup
      - I want to finish above during my stay.
  • Prepare the code of making alignment automaticaly
  14227   Wed Oct 3 18:15:34 2018 yukiConfigurationASCAI board improvement

[ Yuki, Gautam ]

I improved Anti-Imaging board (D000186-Rev.D), which will be put between DAC port and PZT driver board.

It had notches at f = 16.6 kHz and 32.7 kHz, you can see them in the plot attached. So I replaced some resistors as follows:

  • R6 and R7 replaced with 511 ohm (1206 thin film resistor)
  • R8 replaced with 255 ohm (1206 thin film resistor)
  • R14 and R15 replaced with 549 ohm (1206 thin film resistor)
  • R16 replaced with 274 ohm (1206 thin film resistor)

Then the notch moved to 65.9 kHz (> sampling frequency of DAC = 64 kHz, good!). 
(The plot enlarged around the notch frequency and the plot of all channels will be posted later.)

All electronics and optics seem to be ready. 

Reference, elog:40m/8857
Diagram, D000186-D.pdf

Attachment 1: TF_AIboard.pdf
TF_AIboard.pdf
  14228   Thu Oct 4 00:44:50 2018 yukiConfigurationASCAI board improvement

[ Yuki, Gautam ]

I made a cable which connects DAC port (40 pins) and AI board (25 pins). I will check if it works.

Tomorrow I will change setup for improvement of AUX Y-end green locking. Any optics for IR will not be moved in my design, so this work doesn't affect Y-arm locking with main beam. 
While doing this work, I will do:

  • check if the cable works
  • make another cable which connects AI board (10 pins) and PZT driver (10 pins).
  • check if eurocate in Y-rack (IY4?) applies +/-5V, +/-15V and +/-24V. It will be done using an expansion card.
  • improve alignment servo for X-end.
  • setup alignment servo for Y-end.
  • about optical loss measurement.  
  14230   Thu Oct 4 22:15:30 2018 yukiConfigurationASCY-end table upgrade

Before changing setup at Y-end table, I measured the status value of the former setup as follows. These values will be compared to those of upgraded setup.

  • beam power going into doubling crystal (red12): 20.9 mW with filter, 1064nm
  • beam power going out from doubling crystal (red12): 26.7 mW with filter, 532nm
  • beam power going into faraday isolator (green5): 0.58 mW without filter, 532nm
  • beam power going out from faraday isolator (green5): 0.54 mW without filter, 532nm
  • beam power going to ETMY: 0.37 mW without filter, 532nm
  • beam power of transmitted green light of Y-arm, which was measured by C1:ALS-TRY_OUT: 0.5 (see attachment #1)

(These numbers are shown in the attachment #2.)

The setup I designed is here. It can bring 100% mode-matching and good separation of degrees of TEM01, however I found a probrem. The picture of setup is attached #3. You can see the reflection angle at Y7 and Y8 is not appropriate. I will consider the schematic again.

Attachment 1: AUXYGreenLock20180921.jpg
AUXYGreenLock20180921.jpg
Attachment 2: Pic_FormerSetup.jpeg
Pic_FormerSetup.jpeg
Attachment 3: Pic_CurrentSetup1004.jpg
Pic_CurrentSetup1004.jpg
  14231   Fri Oct 5 00:46:17 2018 KojiConfigurationASCY-end table upgrade

???

The SHG crystal has the conversion efficiency of ~2%W (i.e. if you have 1W input @1064, you get 2% conversion efficiency ->20mW@532nm)

It is not possible to produce 0.58mW@532nm from 20.9mW@1064nm because this is already 2.8% efficiency.

 

  14232   Fri Oct 5 17:32:38 2018 yukiConfigurationASCY-end table upgrade

I measured it with the wrong setting of a powermeter. The correct ones are here:

  • beam power going into doubling crystal (red12): 240 mW, 1064nm
  • beam power transmitted dichroic mirror (Y5): 0.70 mW, 532nm
  • beam power going into faraday isolator (green5): 0.58 mW, 532nm
  • beam power going out from faraday isolator (green5): 0.54 mW, 532nm
  • beam power going to ETMY: 0.37 mW, 532nm
  • beam power of transmitted green light of Y-arm, which was measured by C1:ALS-TRY_OUT: 0.5 (see attachment #1)

The calculated conversion efficiency of SHG crystal is 1.2%W.

  14233   Fri Oct 5 17:47:55 2018 gautamConfigurationASCY-end table upgrade

What about just copying the Xend layout? I think it has good MM (per calculations), reasonable (in)sensitivity to component positions, good Gouy phase separation, and I think it is good to have the same layout at both ends. Since the green waist has the same size and location in the doubling crystal, it should be possible to adapt the X end solution to the Yend table pretty easily I think.

Quote:

The setup I designed is here. It can bring 100% mode-matching and good separation of degrees of TEM01, however I found a probrem. The picture of setup is attached #3. You can see the reflection angle at Y7 and Y8 is not appropriate. I will consider the schematic again.

  14234   Fri Oct 5 22:49:22 2018 yukiConfigurationASCY-end table upgrade

I designed a new layout. It has good mode-matching efficiency, reasonable sensitivity to component positions, good Gouy phase separation. I'm setting optics in the Y-end table. The layout will be optimized again after finishing (rough) installation.  (The picture will be posted later)

  14235   Sun Oct 7 16:51:03 2018 gautamConfigurationLSCYarm triggering changed

To facilitate Yuki's alignment of the EY green beam into the Yarm cavity, I have changed the LSC triggering and PowNorm settings to use only the reflected light from the cavity to do the locking of Arm Cavity length to PSL. Running the configure script should restore the usual TRY triggering settings. Also, the X arm optics were macroscopically misaligned in order to be able to lock in this configuration.

  14236   Sun Oct 7 22:30:42 2018 yukiConfigurationLSCYarm Green locking was recovered

I finished installation of optics in the Y-end and recovered green locking. Current ALS-TRY_OUTPUT is about 0.25, which is lower than before. So I still continue the alignment of the beam. The simulation code was attached. (Sorry. The optic shown as QWP2 is NOT QWP. It's HWP.)

Attachment 1: Pic_NewLayout1007.jpg
Pic_NewLayout1007.jpg
Attachment 2: YendGreenModeMatching.zip
  14237   Mon Oct 8 00:46:35 2018 yukiConfigurationASCY-end table upgrade
Quote:

I measured it with the wrong setting of a powermeter. The correct ones are here:

  • beam power going into doubling crystal (red12): 240 mW, 1064nm
  • beam power transmitted dichroic mirror (Y5): 0.70 mW, 532nm
  • beam power going into faraday isolator (green5): 0.58 mW, 532nm
  • beam power going out from faraday isolator (green5): 0.54 mW, 532nm
  • beam power going to ETMY: 0.37 mW, 532nm
  • beam power of transmitted green light of Y-arm, which was measured by C1:ALS-TRY_OUT: 0.5 (see attachment #1)

After installation I measured these power again.

  • beam power going into doubling crystal: 241 mW, 1064nm
  • beam power transmitted dichroic mirror: 0.70 mW, 532nm
  • beam power going into faraday isolator: 0.56 mW, 532nm
  • beam power going out from faraday isolator: 0.53 mW, 532nm
  • beam power going to ETMY: 0.36 mW, 532nm

There is a little power loss. That may be because of adding one lens in the beam path. I think it is allowable margin.

  14238   Mon Oct 8 18:56:52 2018 gautamConfigurationASCc1asx filter coefficient file missing

While pointing Yuki to the c1asx servo system, I noticed that the filter file for c1asx is missing in the usual chans directory. Why? Backups for it exist in the filter_archive subdirectory. But there is no current file. Clearly this doesn't seems to affect the realtime code execution as the ASX model seems to run just fine. I copied the latest backup version from the archive area into the chans directory for now.

  14239   Tue Oct 9 16:05:29 2018 gautamConfigurationASCc1tst deleted, c1asy deployed.

Setting up c1asy:

  • Backed up old c1tst.mdl as c1tst_old_bak.mdl in /opt/rtcds/userapps/release/cds/c1/models
  • Copied the c1tst model to /opt/rtcds/userapps/release/isc/c1/models/c1asy.mdl as this is where the c1asx.mdl file resides.
  • Backed up original c1rfm.mdl as c1rfm_old.mdl in /opt/rtcds/userapps/release/cds/c1/models (since the old c1tst had an RFM block which is unnecessary).
  • Deleted offending RFM block from c1rfm.mdl.
  • Recompiled and re-installed c1rfm.mdl. Model has not yet been restarted, as I'd like suspension watchdogs to be shutdown, but c1susaux EPICS channels are presently not responsive.
  • Removed c1tst model (C-node91) from /opt/rtcds/caltech/c1/target/gds/param/testpoints.
  • Removed /opt/rtcds/caltech/c1/target/gds/param/tpchn_c1tst.par (at this point, DCUID 91 is free for use by c1asy).
  • Moved c1tst line in /opt/rtcds/caltech/c1/target/daqd/master to "old model definitions models" section.
  • Added /opt/rtcds/caltech/c1/target/gds/param/tpchn_c1asy.par to the master file.
  • Edited/diskless/root.jessie/etc/rtsystab to allow c1asy to be run on c1iscey.
  • Finally, I followed the instructions here to get the channels into frames and make all the indicators green.

Now Yuki can work on copying the simulink model (copy c1asx structure) and implementing the autoalignment servo.

Attachment 1: CDSoverview_ASY.png
CDSoverview_ASY.png
  14240   Tue Oct 9 23:03:43 2018 yukiConfigurationLSCYarm Green locking was recovered

[ Yuki, Gautam, Steve ]

To align the green beam in Y-end these hardware were installed:

  • PZT mirrors in Y-end table
  • PZT driver in 1Y4 rack
  • Anti-Imaging board in 1Y4 rack
  • cables (DAC - AIboard - PZTdriver - PZT)
  • high voltage supplier 

I made sure that DAC CH9~16 and cable to AI-board worked correctly. 

When we applied +100V to PZT driver and connected DAC, AI-board and PZT drive, the output voltage of the driver was not correct. I'll check it tomorrow.

Attachment 1: Pic_1Y4.jpg
Pic_1Y4.jpg
Attachment 2: Pic_PZTcable.jpg
Pic_PZTcable.jpg
  14241   Wed Oct 10 12:38:27 2018 yukiConfigurationLSCAll hardware was installed

I connected DAC - AIboard - PZTdriver - PZT mirrors and made sure the PZT mirrors were moving when changing the signal from DAC. Tomorrow I will prepare alignment servo with green beam for Y-arm.

  14257   Mon Oct 15 20:11:56 2018 yukiConfigurationASCY end table upgrade plan

Final Procedure Report for Green Locking in YARM:

Purpose

The current setup of AUX Y-arm Green locking has to be improved because:

  • current efficiency of mode matching is about 50%
  • current setup doesn't separate the degrees of freedom of TEM01 with PZT mirrors (the difference of gouy phase between PZT mirrors should be around 90 deg) 
  • we want to remotely control PZT mirrors for alignment

What to do

  • Design the new setup and order optices needed (finished!)
      - As the new setup I designed, adding a new lens and slightly changing the position of optics are only needed. The new lens was arrived here.
  • Check electronics (PZT, PZT driver, high voltage, cable, anti-imaging board) (finished!)
      
    - All electronics were made sure performing well.
      - The left thing to do is making a cable. (Today's tasks)
  • Calibrate PZT mirror [mrad/V] (finished!)
      
    - The result was posted here --> elog:40m/14224.
  • Measure the status value of the current setup (power of transmitted light ...etc) (finished!)
  • Install them in the Y-end table and align the beam (Almost finished!) (GTRY signal is 0.3 which means Mode-Matching efficiency is about 30%. It should be improved.)
  • Measure the status value of the new setup (finished!)
  • Prepare the code of making alignment automaticaly
    • see sitemap.adl>ASC>c1asy. I prepared medm. If you move PZT SLIDERS then you can see the green beam also moves.
    • Preparing filters is needed. You can copy them from C1ASX.
    • Note that now you cannot use C1ASX servo because filters are not applied.
  14260   Wed Oct 17 20:46:24 2018 yukiConfigurationASCY end table upgrade plan

To do for Green Locking in YARM:

The auto-alignment servo should be completed. This servo requires many parameters to be optimized: demodulation frequency, demodulation phase, servo gain (for each M1/2 PIT/YAW), and matrix elements which can remove PIT-YAW coupling. 

  14301   Fri Nov 16 15:09:31 2018 SteveConfigurationVACnot venting cryo and ion pumps

Notes on the ion pumps and cryo pump:

  • Our 4 ion pumps were closed off for a lomg time. I estmated their pressure to be around ~1 Torr. After talking with Koji we decided not to vent them.

  • It'd be still useful to wire their position sensors. But make sure we do not actuate the valves. 

  • The cryo pump was regenerated to 1e-4 Torr about 2 years ago. It's pressure can be ~ 2 Torr with charcoal powder. It is a dirty system at room temperature.

  • Do not actuate VC1 and VC2, and keep its manual valve closed.

  • IF someone feels we should vent them for some reason, let us know here in the elog before Monday morning.

 

Quote:

Wiring of the power, Ethernet, and indicator lights for the vacuum Acromag chassis is complete. Even though this crate will only use +24V DC, I wired the +/-15V connector and indicator lights as well to conform to the LIGO standard. There was no wiring diagram available, so I had to reverse-engineer the wiring from the partially complete c1susaux crate. Attached is a diagram for future use. The crate is ready to begin software developing on Monday. 

 

  14322   Tue Nov 27 17:06:51 2018 SteveConfigurationVACAgilent 84FS turbo installed as TP2

Chub & Steve,

We swapped in our  replacement of Varian V70D "bear-can" turbo as factory clean.

The new Agilent TwisTorr 84 FS  turbo pump [ model x3502-64002,  sn IT17346059 ]  with intake screen, fan, vent valve. The controller  [ model 3508-64001, sn IT1737C383 ] and a larger drypump IDP-7,  [ model x3807-64010, sn MY17170019 ] was installed.

Next things to do:

  1. implement hardware interlock to close V4 at 80% pumping speed slowdown of "standby" rotation speed, estimated to be ~ 40,000 RPM ( when Standby 50K RPM  )
  2. set up isolation valve in the foreline of TP2, with delayed start of the IDP-7 and/or use relay to power drypump.  This turbo controller can not switch off or start of the dry pump. [ Agilent isolation valve #X3202-60055, with position indicator, pneumatic actuation, 115V solenoid ]..........as a second thought, we do not need isolation valve if we go with the relay option. The IDP-7 has built in delay of 10-15 sec
  3. test performance of new turbo
  14382   Thu Jan 3 21:17:49 2019 ranaConfigurationComputersWorkstation Upgrade: Donatella -> Scientific Linux 7.2

donatella was one of our last workstations running ubuntu12. we installed SL7 on there today

  1. had to use a DVD; wouldn't boot from USB stick
  2. made sure to use userID=1001 and groupID=1001 at the initial install part
  3. went to the Keith Thorne LLO wiki on SL7
  4. The 'yum update' command failed due to a gstreamer conflict. I did "yum remove gstreamer1-plugins-ugly-free-1.10.4-3.el7.x86_64" and then it continued a bit more.
  5. Then there are ~20 errors related to gds-crtools that look like this:Error: Package: gds-crtools-2.18.12-1.el7.x86_64 (lscsoft-production) Requires: libMatrix.so.6.14()(64bit)

  6. I re-ran the yum install .... command using the --skip-broken command and that seemed to complete, although I guess the GDS stuff will not work.
  7. Installed: terminator, inconsolata-fonts, 
  8. Installed XFCE desktop as per K Thorne:  yum groupinstall "Xfce" -y
  9.  
Attachment 1: IMG_20190103_205158.jpg
IMG_20190103_205158.jpg
  14387   Mon Jan 7 11:54:12 2019 JonConfigurationComputer Scripts / ProgramsVac system shutdown

I'm making a controlled shutdown of the vac controls to add new ADC channels. Will advise when it's back up.

  14388   Mon Jan 7 19:21:45 2019 JonConfigurationComputer Scripts / ProgramsVac system shutdown

ADC work finished for the day. The vac controls are back up, with all valves CLOSED and all pumps OFF.

Quote:

I'm making a controlled shutdown of the vac controls to add new ADC channels. Will advise when it's back up.

 

  14476   Fri Mar 8 08:40:26 2019 AnjaliConfiguration Frequency stabilization of 1 micron source

The schematic of the homodyne configuration is shown below.

Following are the list of components

Item Quantity Availability Part number  Remarks
Laser (NPRO) 1 Yes    
Couplers (50/50) 5 3 No's FOSC-2-64-50-L-1-H64F-2 Fiber type : Hi1060 Flex fiber
Delay fiber  two loops of 80 m Yes PM 980

 

One set of fiber is now kept along the arm of the interferometer

InGaAs PD (BW > 100 MHz) 4 Yes NF1611

Fiber coupled (3 No's)

Free space ( 2 No's)

SR560 3 Yes    
  • The fiber mismatch between the couplers and the delay fiber could affect the coupling efficiency
Attachment 1: Homodyne_setup.png
Homodyne_setup.png
  14664   Tue Jun 11 19:25:58 2019 aaronConfigurationBHDReviving the single OMC BHD design?

I drew out some idea of how we might use a single OMC to clean both paths of the BHD after mixing, without being susceptible to polarization-dependent effects within the OMC. Basically, can we send the two legs of the BHD into the OMC counterpropagating. I've attached a diagram.

I think one issue would be scattered light, since any backscatter directly couples into the counterpropagating mode, and thus directly to the PD. However, unless the polarization of the scattered light rotates it would not scatter back to the IFO. And, since the LO and signal mix before the OMC, this scattered light would not directly add phase noise.

Maybe more problematic would be that if the rejection at the PBS (or the polarization rotation) isn't perfect, light from the LO directly couples into the dark port. Can we get away with a Faraday isolator before the OMC? 

Diagram attached.

Attachment 1: singleOMC.pdf
singleOMC.pdf
  14672   Thu Jun 13 22:21:44 2019 KojiConfigurationCDSPaola wireless connected to martian

SURFs had trouble connecting paola to martian via wireless.
Of course, it requires a fixed IP but it had not it yet. So I went to chiara and gave 192.168.113.110 as "paolawl". Note that the wired connection has .111 and it is "paola".

Followed the instruction on http://nodus.ligo.caltech.edu:8080/40m/14121

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