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ID Date Author Type Category Subjectup
  10799   Mon Dec 15 22:30:50 2014 JenneUpdateElectronicsYend QPD modified

Details later - empty entry for a reply.

Short story - Yend is now same as Xend filters-wise and lack of gain sliders -wise.  Both ends have 13.7k resistors around the AD620 to give them gains of ~4.5.

Xend seems fine.

Yend seems not fine.  Even the dark noise spectrum sees giganto peaks.  See Diego's elog 10801 for details on this investigation.

  10801   Mon Dec 15 22:45:59 2014 JenneUpdateElectronicsYend QPD modified

 

 [Jenne, Rana, Diego]

We did some test on the modified QPD board for the Yend; we saw some weird oscillations at high frequencies, so we went and check more closely directly within the rack. The oscillations disappear when the cable from the QPD is disconnected, so it seems something is happening within the board itself; however, looking closely at the board with an oscilloscope in several locations, with the QPD cable connected or disconnected, there is nothing strange and definitely nothing changing if the cable is connected or not. In the plots there are the usual channels we monitor, and the 64kHz original channels before they are downsampled.

Overall it doesn't seem being a huge factor, as the RMS shows at high frequencies, maybe it could be some random noise coming up, but anyway this will be investigated further in the future.

Attachment 1: QPD_Ytrans_oscillating_15Dec2014.pdf
QPD_Ytrans_oscillating_15Dec2014.pdf
Attachment 2: QPD_IOPchannels_Ytrans_oscillating_15Dec2014.pdf
QPD_IOPchannels_Ytrans_oscillating_15Dec2014.pdf
  9845   Thu Apr 24 00:11:35 2014 JenneUpdateLSCYend shutter back.

Quote:

To see if perhaps the shutter was the problem, I turned off the power to the Yend green shutter, and unplugged the cable.  The cable is laying on the table, with the connector sitting on a piece of plastic to isolate it.  Removing the shutter from the system did not change anything.

 I re-plugged in the Yend shutter, and turned it on.

  8437   Wed Apr 10 15:49:22 2013 AnnalisaConfigurationCOMSOL TipsYend table eigenfrequency simulation with COMSOL

 I made a Simulation with COMSOL for the Yend table. Mainly, I tried to see how the lower eigenmode changes with the number and the size of the posts inside.

The lateral frame is just sitting on the table, it is fixed by its weight. I also put a couple of screws to fix it better, but the resulting eigenfrequency didn't change so much (less than 1 Hz). 

In Fig. 1 I didn't put any post. Of course, the lowest eigenfrequency is very low (around 80 Hz).

Then I added 2 posts, one per side (Fig. 2 and Fig. 3), with different diameter.

In some cases posts don't have a base, but they are fixed to the table only by a screw. It is just a condition to keep them fixed to the table

Eventually I put 4 posts, 2 per side. 

The lowest eigenfrequency is always increasing.

At the end I also put a simulation for 4 1.6 inch diameter posts without base, and the eigenfrequency is slightly higher. I want to check it again, because I would expect that the configuration shown in Fig.5a could be more stable.

P.S.: All the post are stainless steel.

 

Attachment 1: Pics_end_table.pdf
Pics_end_table.pdf Pics_end_table.pdf Pics_end_table.pdf
  8302   Fri Mar 15 16:46:52 2013 JenneBureaucracyAuxiliary lockingYend table upgrade - fast track?

In light of the Yend auxiliary laser's ill health, I think we should reconsider the possibility of changing out the Yend laser table next week.

My thinking here is that if whatever the new mode matching solution is for a replacement laser (Tara has borrowed our spare NPRO that used to sit on top of the fridge, or we could take Annalisa's) requires a rework of the table layout, we might as well put the new layout onto the new table.  So, we need to figure out what laser we will put in as the new Ygreen, and what it's waist looks like.  If it just requires a small movement of existing lenses or new lenses in similar positions to the current ones, we can keep living with our current table.  But, if the mode matching solution requires enough changes to distances / lens placement / whatever, we should think seriously about putting in the new table next week.

Here's what I would like to see happen on / before Monday:

Annalisa - Mode matching solution for new laser.  If we get the laser back from Tara, this will involve first measuring the waist, otherwise we already know the waist of the ABSL laser that Annalisa is currently using.

Annalisa and Steve - Find optics for new mode matching in the lab, or order them by Monday afternoon.

Manasa - List of every screw, washer, optic, mount, etc. that will go on the new Y end table, with a notation as to whether or not we have it in-hand, and if not, what needs to happen before we do.  Also, for things that we don't have, I'd like to see a summary of temporary solutions (e.g. keep using current mount for doubling crystal while new one is being machined).

Manasa / Annalisa / Koji - will the new mode matching solution fit within the existing layout, or do we need to redo the table layout?

  8304   Mon Mar 18 12:23:25 2013 JenneBureaucracyAuxiliary lockingYend table upgrade - go fetch NPRO from ATF

Zach has just replied, and said that we should feel free to take the laser from his iodine setup in the West Bridge subbasement, in the ATF lab. 

Annalisa, please ask Koji or Tara to show you where it is, and help you bring it to the 40m.  You should install it (temporarily) on the PSL table, measure the waist, and find the beat in IR.  Elog 3755 and elog 3759 have some of the details on how it has been done in the past.

  8305   Mon Mar 18 12:35:29 2013 AnnalisaBureaucracyAuxiliary lockingYend table upgrade - go fetch NPRO from ATF

Quote:

Zach has just replied, and said that we should feel free to take the laser from his iodine setup in the West Bridge subbasement, in the ATF lab. 

Annalisa, please ask Koji or Tara to show you where it is, and help you bring it to the 40m.  You should install it (temporarily) on the PSL table, measure the waist, and find the beat in IR.  Elog 3755 and elog 3759 have some of the details on how it has been done in the past.

 Ok, I'm going to contact Koji.

  8306   Mon Mar 18 13:10:19 2013 KojiBureaucracyAuxiliary lockingYend table upgrade - go fetch NPRO from ATF

1) Annalisa is going to start  working on mode profiling and beat note search for the old MOPA NPRO.

2) In the meantime, Manasa is working on the end table items. This will be reviewed by KA in the afternoon.

The laser at ATF is moved to the 40m when the status of 1) and 2) is determined by KA to be reasonable.

We also make the beat note measurement for the ATF laser too.
 

  8308   Mon Mar 18 20:13:18 2013 AnnalisaBureaucracyAuxiliary lockingYend table upgrade - go fetch NPRO from ATF

Quote:

1) Annalisa is going to start  working on mode profiling and beat note search for the old MOPA NPRO.

2) In the meantime, Manasa is working on the end table items. This will be reviewed by KA in the afternoon.

The laser at ATF is moved to the 40m when the status of 1) and 2) is determined by KA to be reasonable.

We also make the beat note measurement for the ATF laser too.
 

Today I installed mirrors to steer the pick-off from the main laser beam in a more free part of the PSL table and make the beat note measurement between it and the NPRO.

At the beginning I took the beam from the harmonic separator after the doubling crystal, and I was going to bring it in a less full part of the table . At the end I realized that there was already a beam steered up to a more free part of the table, and the beam is taken from the transmission of the PMC.

Tomorrow I'm going to use that beam to find the beat note with the NPRO.

I also removed almost all the steering  optics that I used on the ITMY table to send the auxiliary beam for ABSL through the window parallel to the POY beam. The most important thing is that I removed the BS, which was on the same path of the POY beam (see elog 8257).

 

  7912   Thu Jan 17 11:01:19 2013 JenneUpdateAlignmentYesterday's alignment work

[Jamie, Jenne, Manasa]

Yesterday's goal was to get the input beam centered on the PRM, the BS and ETMY simultaneously. 

Steve helped us remove the ETMY door first thing in the morning.  We then iterated with TT1, MMT1 and TT2 to try to get the beam centered on all the optics.  We were using MMT1 instead of TT1 for a while, so that we could keep TT1 in the center of its range, so that we had more range to use once we pump down.  Also, at one point, the beam was high on PRM, centered on BS, and high on ETMY, so Jamie poked PR3 a little bit.  This helped, although we closed up for lunch / group meeting soon after, so we didn't finalize any alignment stuff.

We decided to leave the rest of the full IFO alignment alone until after the PRM-flat test.

  15720   Wed Dec 9 16:22:57 2020 gautamUpdateSUSYet another round of Sat. Box. switcharoo

As discussed at the meeting, I decided to effect a satellite box swap for the misbehaving MC1 unit. I looked back at the summary pages Vmon for the SRM channels, and found that in the last month or so, there wasn't any significant evidence of glitchiness. So I decided to effect that swap at ~4pm today. The sequence of steps was:

  • SRM and MC1 watchdogs were disabled.
  • Unplugged the two satellite boxes from the vacuum flanges.
  • For the record: S/N 102 was installed at MC1, and S/N 104 was installed at SRM. Both were de-lidded, supposedly to mitigate the horrible thermal environment a bit. S/N 104 was the one Koji repaired in Aug 2019 (the serial number isn't visible or noted there, but only one box has jumper wires and Koji's photos show the same jumper wires). In June 2020, I found that the repaired box was glitching again, which is when I swapped it for S/N 102.
  • After swapping the two units, I re-enabled the local damping on both optics, and was able to re-lock the IMC no issues.

One thing I was reminded of is that the motion of the MC1 optic by controlling the bias sliders is highly cross-coupled in pitch and yaw, it is almost diagonal. If this is true for the fast actuation path too, that's not great. I didn't check it just now.

While I was working on this, I took the opportunity to also check the functionality of the RF path of the IMC WFS. Both WFS heads seem to now respond to angular motion of the IMC mirror - I once again dithered MC2 and looked at the demodulated signals, and see variation at the dither frequency, see Attachment #1. However, the signals seem highly polluted with strong 60 Hz and harmonics, see the zoomed-in time domain trace in Attachment #2. This should be fixed. Also, the WFS loop needs some re-tuning. In the current config, it actually makes the MC2T RIN worse, see Attachment #3 (reference traces are with WFS loop enabled, live traces are with the loop disabled - sorry for the confusing notation, I overwrote the patched version of DTT that I got from Erik that allows the user legend feature, working on getting that back).

Quote:

The MC1 suspension has begun to show evidence of glitches again, from Friday/Saturday. You can look at the suspension Vmon tab a few days ago and see that the excess fuzz in the Vmon was not there before. The extra motion is also clearly evident on the MCREFL spot. I noticed this on Saturday evening as I was trying to recover the IMC locking, but I thought it might be Millikan so I didn't look into it further. Usually this is symptomatic of some Satellite box issues. I am not going to attempt to debug this anymore.

Attachment 1: WFS2.png
WFS2.png
Attachment 2: WFS_lineNoise.png
WFS_lineNoise.png
Attachment 3: WFSchar.pdf
WFSchar.pdf
  10574   Tue Oct 7 00:18:12 2014 JenneUpdateLSCYgreen PSL alignment, ETMX strain relief

No exciting progress today.  I did PSL green alignment for the Yarm, although I now think that the Xarm green needs realigning too.

Also, I was foiled for a while by ETMX jumping around.  I think it's because the adapter board on the Xend rack didn't have any strain relief.  So, I zip tied the heavy cable in a few places so that it's no longer pulling on the connector.  Hopefully we won't see ETMX misbehaving as often now, so we won't have to go squish cables as often.

  493   Fri May 23 08:24:24 2008 ranaAoGTreasureYoichi Aso has arrived !
Attachment 1: Colossus_back_(800_x_600)-thumb.jpg
Colossus_back_(800_x_600)-thumb.jpg
  505   Thu May 29 16:49:49 2008 steveBureaucracyPhotosYoichi has arrived
Yoichi had his first 40m meeting. We welcomed him and Tobin, who is visiting, by sugar napoleons that
Bob made.
Attachment 1: yoichi.png
yoichi.png
Attachment 2: bobsn.png
bobsn.png
  523   Fri Jun 6 15:56:00 2008 steveBureaucracySAFETYYoichi received safety training
Yoichi Aso received 40m specific safety training.
  1618   Thu May 21 18:21:57 2009 ranaSummaryTreasureYoichi's words

Yoichi's final words on what do next with the interferometer (as of 5 PM on May 21, 2009):

  1. Measure laser noise couplings in spring and anti-spring configurations.
  2. Dewhitening filter turn on for the ETMs.
  3. Noisebudget - import from the sites.
  4. Stabilize CM handoff.

My personal sub-comments to these bullets:

  1. For the laser noise I'm not sure that we will be able to understand these if the couplings are mainly from junk light due to accidental HOM resonances.
  2. WE should look into putting a static passive stage of filtering into the ETMs if warranted by the NB.
  3. Because of the sad track record with this, I will start us off this time by importing and modifying the H1/L1 versions.
  4. I guess we can do this by just acquiring on MC2 with the huge CARM offset. It works for the single arm so it should work for offset CARM.
  3637   Fri Oct 1 16:46:20 2010 steveBureaucracySAFETYYuta received 40m-101-safety training

Our visiting graduate student Yuta Michimura received 40m specific basic safety training today.

  5052   Thu Jul 28 13:51:00 2011 SonaliUpdateGreen LockingZHL-32A-S.

Initially I was using RFPD-1611to get the IR beat frequency. Its gain was not very high, so I was getting a very low signal of power -37 dBm.

I used ZHL-32A-S with a gain of 25 dBm to amplify it before feeding it into the spectrum analyser.

I connected the ground of the amplifier circuit to the red of the power supply, which blew the amplifier.

I learnt that there is a small tab indicating the ground side of the BNC to banana connectors which I should have noticed.

I learnt to plug in the side with th little tab on it into the ground of the power supply. (Learnt it the hard way I guess!!)

 

 

  15031   Fri Nov 15 18:59:08 2019 ranaUpdateComputersZITA: started upgrade from Ubuntu 14 LTS to 18 LTS

and so it begins...until this is finished I have turned off the projector and moved the striptools to the big TV (time to look for Black Friday deals to replace the projector with a 120 inch LED TV)

  15033   Mon Nov 18 16:32:15 2019 gautamUpdateComputersZITA: started upgrade from Ubuntu 14 LTS to 18 LTS

the upgrade seems to have been successfully executed - the machine was restarted at ~430pm local time. Projector remains off and diagnostic striptools are on the samsung.

Quote:

and so it begins...until this is finished I have turned off the projector and moved the striptools to the big TV (time to look for Black Friday deals to replace the projector with a 120 inch LED TV)

  16156   Mon May 24 10:19:54 2021 PacoUpdateGeneralZita IOO strip

Updated IOO.strip on Zita to show WFS2 pitch and yaw trends (C1:IOO-WFS2_PIY_OUT16 and C1:IOO-WFS2_YAW_OUT16) and changed the colors slightly to have all pitch trends in the yellow/brown band and all yaw trends in the pink/purple band.

No one says, "Here I am attaching a cool screenshot, becuz else where's the proof? Am I right or am I right?"

Mon May 24 18:10:07 2021 [Update]

After waiting for some traces to fill the screen, here is a cool screenshot (Attachment 1). At around 2:30 PM the MC unlocked, and the BS_Z (vertical) seismometer readout jumped. It has stayed like this for the whole afternoon... The MC eventually caught its lock and we even locked XARM without any issue, but something happened in the 10-30 Hz band. We will keep an eye on it during the evening...

Tue May 25 08:45:33 2021 [Update]

At approximately 02:30 UTC (so 07:30 PM yesterday) the 10-30 Hz seismic step dropped back... It lasted 5 hours, mostly causing BS motion along Z (vertical) as seen by the minute trend data in Attachment 2. Could the MM library have been shaking? Was the IFO snoring during its afternoon nap?

Attachment 1: Screenshot_from_2021-05-24_18-09-37.png
Screenshot_from_2021-05-24_18-09-37.png
Attachment 2: 24and25_05_2021_PEM_BS_10_30.png
24and25_05_2021_PEM_BS_10_30.png
  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
DSC01773.JPG
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.

  15561   Sun Sep 6 14:17:18 2020 JonUpdateEquipment loanZurich Instruments analyzer

On Friday, I grabbed the Zurich Instruments HF2LI lock-in amplifier and brought it home. As time permits, I will work towards developing a similar readout script as we have for the SR785.

  16226   Fri Jun 25 19:14:45 2021 JonUpdateEquipment loanZurich Instruments analyzer

I returned the Zurich Instruments analyzer I borrowed some time ago to test out at home. It is sitting on first table across from Steve's old desk.

Attachment 1: ZI.JPG
ZI.JPG
  11033   Sun Feb 15 16:20:44 2015 KojiSummaryLSC[ELOG LIST] 3f modulation cancellation

Summary of the ELOGS

3f modulation cancellation theory http://nodus.ligo.caltech.edu:8080/40m/11005

3f modulation cancellation adjustment setup http://nodus.ligo.caltech.edu:8080/40m/11029

Experiment http://nodus.ligo.caltech.edu:8080/40m/11031

Receipe for the 3f modulation cancellation http://nodus.ligo.caltech.edu:8080/40m/11032

Modulation depth analysis http://nodus.ligo.caltech.edu:8080/40m/11036

  11034   Sun Feb 15 20:55:48 2015 ranaSummaryLSC[ELOG LIST] 3f modulation cancellation

I wonder if DRMI can be locked on 3f using this lower 55 MHz modulation depth. It seems that PRMI should be unaffected, but that the 3*f2 signals for SRCL will be too puny. Is it really possible to scale up the overall modulation depths by 3x to compensate for this?

  11035   Mon Feb 16 00:08:44 2015 KojiSummaryLSC[ELOG LIST] 3f modulation cancellation

This KTP crystal has the maximum allowed RF power of 10W (=32Vpk) and V_pi = 230V. This corresponds to the maximum allowed
modulation depth of 32*Pi/230 = 0.44. So we probably can achieve gamma_1 of ~0.4 and gamma_2 of ~0.13. That's not x3 but x2,
so sounds not too bad.

Then Kiwamu's triple resonant circuit LIGO-G1000297-v1 actually shows the modulation up to ~0.7. Therefore it is purely an issue
how to deliver sufficient modulation power. (In fact his measurement shows some nonlinearity above the modulation depth of ~0.4
so we should keep the maximum power consumption of 10W at the crystal)

This means that we need to review our RF system (again!)

- Review infamous crazy attn/amp combinations in the frequency generation box.
- Use Teledyne Cougar ampilfier (A2CP2596) right before the triple resonant box. This should be installed closely to the triple resonant box in order to
minimize the effects of the reflection due to imperferct impedance matching.
- Review and refine the triple resonant circuit - it's not built on a PCB but on a universal board. I think that we don't need triple
resonance, but double is OK as the 29.5MHz signal is small.

We want +28V supply at 1X1 for the Teledyne amp and the AOM driver. Do we have any unused Sorensen?

  3815   Thu Oct 28 23:17:15 2010 yutaSummaryCDS[EMERGENCY] accidentally deleted daqd

Rana showed me that if c1sus machine runs c1mcs stuff(and c1x02 stuff) only, we can use dataviewer without crashing fb.
Also, if we set correct NDS server and port(fb/8088), we can use diaggui on every machine.


During my investigation on what he did, I accidentally deleted daqd......
I am very very sorry.

I don't know if it helps or not, but all I have is the following information:

[Backup?]
    /opt/rtcds/caltech/c1/target/fb/daqd.25sep10


[What I deleted]
   -rwxr-xr-x 1 controls controls 6583071 Oct  1 11:57 daqd


[help message for daqd existed]
CDS Data Acquisition Server, Frame Builder, version 2.0
California Institute of Technology, LIGO Project
Client communication protocol version 11.4

Usage:
        daqd [-f <input frame file name>]
        [-c <configuration file (default -- $HOME/.daqdrc)>]

        [-s <frame writer pause usec (default -- 1 sec)>]


This executable compiled on:
        Fri Oct  1 10:33:18 PDT 2010
        Linux fb 2.6.34.1 #7 SMP Fri Sep 24 14:09:53 PDT 2010 x86_64 Dual-Core AMD Opteron(tm) Processor 8220 AuthenticAMD GNU/Linux



Please help me, Joe.

  3821   Fri Oct 29 11:25:15 2010 josephb, yutaSummaryCDS[EMERGENCY] accidentally deleted daqd

Problem:

Missing daqd file, i.e. the framebuilder executable.

Solution:

1) Go to /opt/rtcds/caltech/c1/core/advLigoRTS/

2) Look in the Makefile for a likely build suspect.  In this case it was build dc, which stands for data concentrator.

3) So we ran "make dc"

4) Go to the sub-directory build/dc/ and then copy the daqd file there to the /opt/rtcds/caltech/c1/target/fb directory

5) Test it to ensure we're getting channels (Yay!)

Future Safeguards:

Place the new target directory under SVN control.

 

  9007   Tue Aug 13 17:20:54 2013 KojiUpdateCDS[Fixed] c1iscex needs help

c1x01 timing issue was solved. Now all of the models on c1iscex are nicely running.

Symptons

- c1x01 was synchronized to 1PPS in stead of TDS

- C1:DAQ-DC0_C1X01_STATUS (Upper right indicator) was red. The bits were 0x4000 or 0x2bad.
  C1:DAQ-DC0_C1X01_CRC_SUM kept increasing

 - c1scx, c1spx, c1asx could not get started.

Solution

- login to c1iscex "ssh c1iscex"

- Run "sudo shutdown -h now"

- Walk down to the x end rack

- Make sure the supply voltages for the electronics are correct (See Steve's entry)

- Make sure the machine is already shutdown.

- Unplug two AC power supply of the machine.

- Turn off the front panel switch of the IO chassis

- Wait for 10sec

- Turn on the IO chassis

- Plug the AC power supply cables to the machine

- Push the power switch of the realtime machine

  11032   Sat Feb 14 22:14:02 2015 KojiSummaryLSC[HOW TO] 3f modulation cancellation

When I finished my measurements, the modulation setup was reverted to the conventional one.
If someone wants to use the 3f cancellation setting, it can be done along with this HOW-TO.


The 3f cancellation can be realized by adding a carefully adjusted delay line and attenuation for the 55MHz modulation
on the frequency generation box at the 1X2 rack.  Here is the procedure:

1) Turn off the frequency generation box

There is a toggle switch at the rear of the unit. It's better to turn it off before any cable action.
The outputs of the frequency generation box are high in general. We don't want to operate
the amplifiers without proper impedance matching in any occasion.

2) Remove the small SMA cable between 55MHz out and 55MHz in (Left arrow in the attachment 1).

According to the photo by Alberto (svn: /docs/upgrade08/RFsystem/frequencyGenerationBox/photos/DSC_2410.JPG),
this 55MHz out is the output of the frequency multiplier. The 55MHz in is the input for the amplifier stages.
Therefore, the cable length between these two connectors changes the relative phase between the modulations at 11MHz and 55MHz.

3) Add a delay line box with cables (Attachment 2).

Connect the cables from the delay line box to the 55MHz in/out connectors. I used 1.5m BNC cables.
The delay line box was set to have 28ns delay.

4) Set the attenuation of the 55MHz EOM drive (Right arrow in the attachment 1) to be 10dB.

Rotate the attenuation for 55MHz EOM from 0dB nominal to 10dB.

5) Turn on the frequency modulation box


For reference, the 3rd attachment shows the characteristics of the delay line cable/box combo when the 3f modualtion reduction
was realized. It had 1.37dB attenuation and +124deg phase shift. This phase change corresponds to the time delay of 48ns.
Note that the response of a short cable used for the measurement has been calibrated out using the CAL function of the network analyzer.

Attachment 1: freq_gen_box.JPG
freq_gen_box.JPG
Attachment 2: delay_line.JPG
delay_line.JPG
Attachment 3: cable_spec.pdf
cable_spec.pdf
  16663   Thu Feb 10 21:51:02 2022 KojiUpdateCDS[Solved] Huge random numbers flowing into ETMX/ETMY ASC PIT/YAW

Huge random numbers are flowing into ETMX/ETMY ASC PIT/YAW. Because of this, I could not damp the ETMX/ETMY suspension at the beginning during the recovery from rebooting. (Attachment 1)
By turning off the output of the ASC filters, the mirrors were successfully damped.

Looking at the FE model view of the end RTSs, there were two possibilities: (Attachment 2)

- They are coming from RFM connection
- They are coming from ASXASY

ASX/ASY are not active and I could not see anything producing these numbers. Burtrestore didn't help.

The possibility was something at the other side of the RFM, or corruption of the RFM signal.

- Looking at the RFM model (Attachment 3), the ASC signals are coming from ASS and IOO. The ASS path has the filter module (C1:RFM-ETMX_PIT and etc). This FM is quiet and not guilty.

- Why do we have the RFM from IOO? I went to IOO and found the new ASC (WFS) model is there. I didn't realize the presence of this model. In fact ASC screen showed that these random numbers are flowing into the end SUSs.
So I did burtrestore of c1iooepics. Alas! they are gone.

Now I can go home.

Attachment 1: Screenshot_2022-02-10_21-46-02.png
Screenshot_2022-02-10_21-46-02.png
Attachment 2: Screen_Shot_2022-02-10_at_21.54.21.png
Screen_Shot_2022-02-10_at_21.54.21.png
Attachment 3: Screen_Shot_2022-02-10_at_22.14.23.png
Screen_Shot_2022-02-10_at_22.14.23.png
  16664   Fri Feb 11 10:56:38 2022 AnchalUpdateCDS[Solved] Huge random numbers flowing into ETMX/ETMY ASC PIT/YAW

Yeah, this is a known issue actually. We go to ASC screen and manually swich off all the outputs after every reboot. We haven't been able to find a way to set default so that when the model comes online, these outputs remain switched off. We should find a way for this.

 

  16666   Fri Feb 11 12:22:19 2022 ranaUpdateCDS[Solved] Huge random numbers flowing into ETMX/ETMY ASC PIT/YAW

you can hand edit the autoBurt file which the FE uses to set the values after boot up. Just make a python script that amends all of the OFF or ZERO that are needed to make things safe. This would be the autoBurt snap used on boot up only, and not the hourly snaps.

 

Yeah, this is a known issue actually. We go to ASC screen and manually swich off all the outputs after every reboot. We haven't been able to find a way to set default so that when the model comes online, these outputs remain switched off. We should find a way for this.

 

  16668   Fri Feb 11 17:07:19 2022 AnchalUpdateCDS[Solved] Huge random numbers flowing into ETMX/ETMY ASC PIT/YAW

The autoBurt file for FE already has the C1:ASC-ETMX_PIT_SW2 (and other channels for ETMY, ITMX, ITMY, BS and for YAW) present, and I checked the last snapshot file from Feb 7th, 2022, which has 0 for these channels. So I'm not sure why when FE boots up, it does not follow the switch configuration. Fr safety, I changed all the gains of these filter modules, named like C1:ASC-XXXX_YYY_GAIN (where XXXX is ETMX, ETMY, ITMX, ITMY, or BS , and YYY is PIT or YAW) to 0.0. Now, even if the FE loads with switches in ON configuration, nothing should happen. In future, if we use this model for anything, we can change the gain values which won't be hard to track as the reason why no signal moves forward. Note, the BS connections from this model to BS suspension model do not work.

Quote:

you can hand edit the autoBurt file which the FE uses to set the values after boot up. Just make a python script that amends all of the OFF or ZERO that are needed to make things safe. This would be the autoBurt snap used on boot up only, and not the hourly snaps.

 

Yeah, this is a known issue actually. We go to ASC screen and manually swich off all the outputs after every reboot. We haven't been able to find a way to set default so that when the model comes online, these outputs remain switched off. We should find a way for this.

 

 

  13351   Mon Oct 2 19:03:49 2017 gautamUpdateCDS[Solved] c1ioo DC errors

This did the trick - I simply ran

sudo systemctl restart daqd_*

on FB1, and now all the CDS overview lights are green again.

I thought I had done this already, but I realize that I was supposed to restart the daqd processes on FB1 (which is where they are running) and not on c1ioo frown.

Thanks Jamie for the speedy resolution!

Quote:
Quote:

 

  • This time the model came back up but I saw a "0x2000" error in the GDS overview MEDM screen.
  • Since there are no DACs installed in the c1ioo expansion chassis, I thought perhaps the problem had to do with the fact that there was a "DAC_0" block in the c1x03 simulink diagram - so I deleted this block, recompiled c1x03, and for good measure, restarted all (three) models on c1ioo.
  • Now, however, I get the same 0x2000 error on both the c1x03 and c1als GDS overview MEDM screens (see Attachment #1).

From page 21 of T1100625, DAQ status "0x2000" means that the channel list is out of sync between the front end and the daqd.  This usually happens when you add channels to the model and don't restart the daqd processes, which sounds like it might be applicable here.

It looks like open-mx is loaded fine (via "rtcds lsmod"), even though the systemd unit is complaining.  I think this is because the open-mx service is old style and is not intended for module loading/unloading with the new style systemd stuff.

 

Attachment 1: CDSoverview.png
CDSoverview.png
  985   Tue Sep 23 13:25:07 2008 robUpdateLockinga bit better
I've been spending time working on the short DOF loops (PRC,MICH,SRC) in an attempt to make the
initial stage of lock acquisition (the DRMI+2ARMs, no spring) better. This seems to have been
largely successful, as last night there were several locks of the DRMI+2ARMs with pretty short
wait times.

The output matrix for the short DOFs is a bit strange, though. The MICH->PRM element is about
3 times too small, which seems to indicate something broken in hardware. The MICH->SRM element
seems normal, though, which suggests the BS is isn't broken--either the PRM has had a sudden
actuation increase or it's a problem with the sensing.
  3112   Thu Jun 24 01:02:34 2010 Sharmilla, Rana and KiwamuUpdateGreen Lockinga channel for PPKTP temperature

We added a channel on c1psl in order to monitor the temperature of the PPKTP sitting on the PSL table.

To take continuous data of the temperature we added the channel by editing the file: target/c1psl/c1psl.db

We named the channel "C1:PSL-PPKTP_TEMP".

To reflect this change we physically rebooted c1psl by keying the crate.

  3113   Thu Jun 24 06:49:29 2010 AidanUpdateGreen Lockinga channel for PPKTP temperature

Is this a setpoint temperature that we can change by writing to the channel or is it a readout of the actual temperature of the oven?

kiwamu:

This is a readout channel just to monitor the actual temperature.

Quote:

We added a channel on c1psl in order to monitor the temperature of the PPKTP sitting on the PSL table.

  4294   Tue Feb 15 02:13:16 2011 kiwamuSummaryASCa daytime task : small signals on ETMX OL

Rana and I found that the QPD for the optical lever at X end are showing small signals.

At this moment each of the segments exhibits approximately 200 counts when the oplev beam is centered.

These small numbers may be due to the coating of ETMX, but we are not sure.

Probably we have to increase the gain of the QPD depending on situations.

 

So a set of the tomorrow's daytime task is:

   1. check the trend data of the QPD outputs to see how much signals were there in the past.

   2. check the whitening filters to make sure if it's on or off.

   3. If it's necessary, increase the gain of the QPD to have reasonable readouts.

I am going to ask somebody to do this task.

  5369   Fri Sep 9 13:29:09 2011 kiwamuUpdateIOOa history of PZT mirror

Something happened about 8 years ago.

Old iLog entry by AJW (2003/Sep/8)

Old iLog entry by AJW (2003/Sep/9)

Quote:

Last night I noticed that PZT1 didn't work properly

 

  4449   Mon Mar 28 17:06:15 2011 kiwamuUpdateGreen Lockinga mixer school

In the last week Matt and I modified the MFD configuration because the mixer had been illegally used.

 

mixers.png

Since the output from the comparator is normally about 10 dBm, a 4-way power splitter reduced the power down to 4 dBm in each output port.

In order to reserve a 7 dBm signal to a level-7 mixer, we decided to use an asymmetric power splitter, which is just a combination of 2-way and 3-way splitter shown in the diagram above.

With this configuration we can reserve a 7 dBm signal for a mixer in the fine path.

However on the other hand we sacrificed the coarse path because the power going to the mixer is now 2.2 dBm in each port.

According to the data sheet for the mixer, 1 dB compression point for the RF input is 1dBm. Therefore we put a 1 dB attenuator for the RF port in the coarse system.

In the delay line of the fine path we found that the delay cable was quite lossy and it reduced the power from 2.2 dBm to about 0 dBm.

 

 

  4450   Mon Mar 28 18:13:32 2011 ranaUpdateGreen Lockinga mixer school

Using 2 dBm for a Level 7 mixer is so bogus, that I will dismantle this as soon as I come over.

http://www.minicircuits.com/products/amplifiers_main.html

  4451   Mon Mar 28 18:22:43 2011 kiwamuUpdateGreen Lockinga mixer school

PLEASE DO NOT DISMANTLE THE SETUP !

Actually we tried looking for a level-3 or a smaller mixer, but we didn't find them at that moment. That's why we kept the level-7 mixer for the coarse path.

As you pointed out we can try an RF amplifier for it.

Quote:

Using 2 dBm for a Level 7 mixer is so bogus, that I will dismantle this as soon as I come over.

http://www.minicircuits.com/products/amplifiers_main.html

 

  4923   Thu Jun 30 14:11:55 2011 kiwamuUpdateABSLa photo of ABSL setup on the AP table

Here is a picture of the latest ABSL setup at the east part of the AP table.

ABSLsetup.png

 

(Some notes )

 - The ABSL laser is injected from the AP port.

  - A 90 % reflection BS was installed just after the NPRO, this is for sampling a 10% of the laser to the PSL table.

    However, I've just realized that this is not a nice way because the 10 % beam doesn't  go through the Faraday. Whoops.

 - A polarzser cell at the input side of the Faraday doesn't let any beam go through it for some reasons (broken ?).

    Therefore instead of having such a bad cell, a cube PBS was installed.

 -  A room was left on the table for the AS165 RFPD (green-dashed rectangular in the picture).

Quote from #4917

 - Also a picture of the setup will be uploaded in the morning.

 

  4850   Tue Jun 21 20:35:50 2011 kiwamuUpdateLSCa script to measure sensing matrix

Last night I was making a script which will measure the sensing matrix using the realtime LOCKIN module.

The script is a kind of expansion of Jamie's one, which measure the asymmetry, to more generic purpose.

It will shake a suspended optic of interest and measure the response of each sensor by observing the demodulated I and Q signals from the LOCKIN module.

I will continue working on this.

 

  (current status)

 - made a function that drives the LOCKIN oscillator and get the data from the I and Q outputs.

 - checked the function with the MICH configuration.

   ITMX, ITMY and BS were shaken at 100 Hz and at different time.

   Then the response of AS55_Q showed agreement with what I got before for the actuator calibration (see this entry).

   It means the function is working fine.

Attachment 1: elog.png
elog.png
  4778   Wed Jun 1 21:56:43 2011 KojiUpdateGeneralaLIGO BBPD / Green PD final result

Here is the conclusive result for the circuit configuration for aLIGO BBPD and 40m Green PD.

- Use Mini-circuits MAR-6SM for the RF preamplifier. The 50Ohm input impedance is used for the RF transimpedance.
  The maximum output is ~4dBm.

- Use Mini-circuits GALI-6 for the RF middle power amp. The gain is 12dB and the amplifier is linear up to +17dBm. i.e. This is still linear at the maximum output level of MAR-6SM.

- The total RF transimpedance is ~2k. The DC transimpedance is also 2k.

- The bandwidth is 80MHz with FFD100 and internal 25V bias. When S3399 is used, the bandwdith goes up to 180MHz
although the responsivity of FFD100 at 1064nm is better than S3399 by a factor of 1.5. At the 40m we will use S3399 for the green BB PD.

- By adding an LC network next to the PD, one of the unnecessary signal can be notched out.
As an example, 9MHz notch was placed for the FFD100 case.

- Noise level: ~10pA/rtHz as a floor noise level at around 30MHz. This corresponds to the equivalent dark current of 0.4mA.


Matt has finished the PCB layout. We will order small first batches, and stuff it for the test. Some of these will be the 40m green PD.

Attachment 1: PD_response.pdf
PD_response.pdf PD_response.pdf PD_response.pdf PD_response.pdf PD_response.pdf PD_response.pdf
Attachment 2: linearity_GALI_6.pdf
linearity_GALI_6.pdf
  4649   Fri May 6 01:27:12 2011 KojiSummaryGeneralaLIGO BBPD / Green PD investigation

Minicircuits ERA-5SM was used for the RF amp of the BBPD. This amp is promising as a replacement of Teledyne Cougar AP389
as ERA-5SM gave us the best performance so far among the BBPDs I have ever tested for the aLIGO BBPD/Green.

The -3dB bandwidth of ~200MHz and the noise floor at the shotnoise level of 0.7mA DC current were obtained.


1. Introduction

The aLIGO BBPD candidate (LIGO Document D1002969-v7) employs Teledyne Cougar AP389 as an RF amplifier.
This PD design utilizes the 50Ohm termination of the RF amp as a transimpedance resistance at RF freq.

However, it turned out that the bandwidth of the transimpedance gets rather low when we use AP389, as seen in the attachment2.
The amplifier itself is broadband upto 250MHz (the transfer function was confirmed with 50Ohm source).
The reason is not understood but AP389 seems dislike current source. Rich suggested use of S-parameter measurement
to construct better model of the curcuit.

On the other hand, the RF amplifiers from Minicircuits (coaxial type like ZFL-1000LN+), in general, exhibit better compatibility with PDs.
If you open the amplifier case, you find ERA or MAR type monolithic amplifiers are used.

So the question is if we can replace AP389 by any of ERA or MAR.

2. Requirement for the RF amp

- The large gain of the RF amp is preffered as far as the output does not get saturated.

- The amplifier should be low noise so that we can detect shot noise (~1mA).

- The freq range of the useful signal is from 9MHz to 160MHz.

The advanced LIGO BBPD is supposed to be able to receive 50mW of IR or 15mW of 532nm. This approximately corresponds to
5mA of DC photocurrent if we assume FFD-100 for the photodiode. At the best (or worst) case, this 5mA has 100% intensity modulation.
If this current is converted to the votage through the 50Ohm input termination of the RF amp, we receive -2dBm of RF signal at maximum.

This gives us a dilemma. if the amp is low noise but the maximum output power is small, we can not put large amount of light
on the PD. If the amp has a high max output power (and a high gain), but the amp is not low noise, the PD has narrow power range
where we can observe the shotnoise above the electronics noise.

What we need is powerful, high gain, and low noise RF amplifier!

Teledyne Cougar AP389 was almost an ideal candidate before it shows unideal behavior with the PD.
Among Minicircuits ERA and MAR series, ERA-5 (or ERA-5SM) is the most compatible amplifier.


AP389 ERA-5
Freq Range 10-250MHz DC-4GHz
Gain >24.5dB 20dBtyp
Output power (1dB compression)
23dBm 18.4dBm
IP3 36dBm 33dBm
Noise Figure <3.3dB 3.5dB

Considering the difference of the gain, they are quite similar for our purpose. Both can handle upto -2dBm,
which is just the right amount for the possible maximum power we get from the 5mA of photocurrent.

3. Test circuit with ERA-5SM

A test circuit has been built (p.1 attachment #1) on a single sided prototype board. 

First, the transfer function was measured with FFD-100. With the bias 100V (max) the -3dB bandwidth of ~200MHz was observed.
This decreases down to 75MHz if the bias is 25V, which is the voltage supplied by the aLIGO BBPD circuit. The transimpedance
at the plateau was ~400Ohm.

Next, S3399 was tested with the circuit. With the bias 25V and 30V (max) the -3dB bandwidth of ~200MHz was obtained although
the responsivity of S3399 (i.e. A/W) at 1064nm is about factor of 2 smaller than that of FFD-100.

The noise levels were measured. There are many sprious peaks (possibly by unideal hand made board and insufficient power supply bypassing?).
Othewise, the floor level shows 0.7mA shotnoise level.

Attachment 1: PD_response.pdf
PD_response.pdf PD_response.pdf PD_response.pdf PD_response.pdf
Attachment 2: FFD-100_AP389_MCL.pdf
FFD-100_AP389_MCL.pdf
ELOG V3.1.3-