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ID Date Author Type Category Subjectup
  7030   Wed Jul 25 16:31:01 2012 JenneUpdateLSCYarm green locking to arm - PDH box saturating

Quote:

... it was not possible to get the cavity locked in green. So we decided to do the first measurement with infrared locked only. 

 When we sat down to align the Yarm to the green, the green light was happy to flash in the cavity, but wouldn't lock, even after Jan had tweaked the mirrors such that we were flashing the TEM00 mode.  When we went down to the end to investigate, the Universal PDH box was saturating both negative and positive.  Turning down the gain knob all the way to zero didn't change anything, so I put it back to 52.5.  Curiously, when we unplugged the Servo OUT monitor cable (which was presumably going to the rack to be acquired), the saturation happened much less frequently.  I think (but I need to look at the PDH box schematic) that that's just a monitor, so I don't know why that had to do with anything, but it was repeatable - plug cable in, almost constant saturation....unplug cable, almost no saturation.

Also, even with the cable unplugged, the light wouldn't flash in the cavity.  When I blocked the beam going to the green REFL PD (used for the PDH signal), the light would flash.

Moral of the story - I'm confused.  I'm going to look up the PDH box schematic before going back down there to investigate.

  8825   Thu Jul 11 03:14:19 2013 JenneUpdateLSCYarm held nicely on IR resonance with ALS, PRMI+arm attempt

[Annalisa, Jenne, Nic]

After having troubles with the Xarm earlier (maybe Manasa can write/say something about this?  Something about perhaps seeing the phase tracker jump, and cause it to lose lock?), we moved on to the Y arm. 

Annalisa locked the Yarm green, and closed the ALS loop.  I believe that earlier today, she tuned the gain such that we don't start getting gain peaking at a few hundred Hz.  We would like to get a script going, so that it's not so labor intensive to reclose the ALS loop after an MC lockloss....but that's a daytime task.

We then found the IR resonance, using only the Yarm ALS system.  After Manasa's work yesterday, the Yarm was very stable while locked with the ALS.  We took a power spectrum of POY11_I_ERR, which I have calibrated using the number in elog 6834 of 1.4e12 cts/m, or 7.14e-13 m/ct.  See the figure below.

After that, we changed the offsetter2 offset such that the arm was off resonance, but not so far off that we crossed any significant resonances (in particular, we wanted to not go as far as the 55MHz resonance). 

Then, I tried to lock the PRMI for a while, but the alignment wasn't very good.  We knew that the Yarm was well aligned, since our IR resonance was > 0.98, but it had been a while since we had aligned the X arm.  I tweaked the ITMX position to make the Michelson dark, and then tried acquiring PRMI lock.  At first, I tried with REFL165 I and Q, but with the non-ideal alignment and the offset in the 165 diode (LSC offsets was not run this evening), I wasn't catching any locks.  I then switched to AS55Q and REFL33I, but wasn't able to catch lock there either. 

The MC lost lock, which made us lose the ALS loop, but the ALS had been locked for more than 30 minutes, at least.  I tried locking the PRMI with the current alignment (after having misaligned ETMY), but was only able to get lock stretches of 1 second at maximum.

We are calling it a great success for the night, since we have confirmed that, at least for the Yarm, Manasa's beatbox work has improved things.  Also, we have a pretty solid plan for trying the PRMI+arm tomorrow, even though it didn't work out tonight.

  8826   Thu Jul 11 07:34:42 2013 manasaUpdateLSCYarm held nicely on IR resonance with ALS, PRMI+arm attempt

Quote:

We knew that the Yarm was well aligned, since our IR resonance was > 0.98, but it had been a while since we had aligned the X arm. 

 The X arm was locked with TRX>0.98 earlier last night while I was measuring the out of loop noise of the phase tracker.

  14403   Wed Jan 16 16:25:25 2019 gautamUpdateSUSYarm locked

[chub, gautam]

Summary:

Y arm was locked at low power in air.

Details:

  1. ITMY chamber door was removed at ~10am with Bob's help.
  2. ETMY table leveling was found to have drifted significantly (3 ticks on the spirit level, while it was more or less level yesterday, should look up the calib of the spirit level into mrad). Chub moved some weights around on the table, we will check the leveling again tomorrow.
  3. IMC was locked.
  4. TT2 and brass alignemnt tool was used to center beam on ETMY.
  5. TT1 and brass alignment tool was used to center beam on ITMY. We had to do a c1susaux reboot to be able to move ITMY. Usual precautions were taken to avoid ITMX getting stuck.
  6. ETMY was used to make return beam from the ETM overlap with the in-going beam near ITMY, using a holey IR card.
  7. At this point, I was confident we would see IR flashes so I decided to do the fine alignment in the control room.

We are operating with 1/10th the input power we normally have, so we expect the IR transmission of the Y arm to max out at 1 when well aligned. However, it is hovering around 0.05 right now, and the dominant source of instability is the angular motion of ETMY due to the Oplev loop being non-functional. I am hesitant to do in-chamber work without an extra pair of eyes/hands around, so I'll defer that for tomorrow morning when Chub gets in. With the cavity axis well defined, I plan to align the green beam to this axis, and use the two to confirm that we are well clear of the Parabola.

* Paola, our vertex laptop, and indeed, most of the laptops inside the VEA, are not ideal to work on this kind of alignmment procedure, it would be good to set up some workstations on which we can easily interact with multiple MEDM screens,

  7723   Mon Nov 19 15:12:52 2012 JenneUpdateAlignmentYarm locked IR

Quote:

Quote:

POY11 does not go out of the vacuum

 It does but slighty low and does not get on mirrors. We need to change optic mounts to adjust the height. Red is flashing in yarm at 00 and 10 modes. TRY is ~0.4-0.5.

I've adjusted BS angle, camera and TRX PD at ETMX table so I can see red flashing at 03 mode while green is locked to 00 and its transmission is maximized. I thought that by adjusting BS angle, I will be able to align red to 00 not disturbing green, but this was not the case. Maximum TRX I could get was 0.1. I've adjusted POX to get into PD and I can see PDH signal though I can't lock as cavity is still misaligned for red.

 [Ayaka, Jenne]

We put the POY beam onto the POY PD.  The Yarm is currently locked on IR with ~0.65 transmission.

 

  9888   Thu May 1 03:15:03 2014 JenneUpdateLSCYarm locking with CM board

[Rana, EricQ, Jenne]

We locked the Yarm by using the CM board this evening. 

POY is going from its demod board to the CM board, and then the slow output of that is going to the POY channel of the whitening, and then on to the ADC.  So, with no AO path engaged, this is basically like regular Yarm locking. 

First of all, Den and Koji back in December were concerned that they were seeing some EOM saturation in the fast path, but we don't think that's an issue.  We looked at the FSS PCDRIVE while we increased the AO gain.  In fact, it looks like the offset is coming from the MC board's IN2 slider.  Even with no input on that slider, increasing its value puts an offset into the MC.  To fix this, I am going to put a 6.8uF cap in series with R30 in the MC board, which is part of the crossbar switch where the IN1 and IN2 get summed.  This should AC-couple the output of the IN2 slider before the summing node.

We aren't sure which sign to use for the AO path of the CM board...Eric is doing some modelling to see if he can figure it out.  He's going to try to see which spectra (below) his model matches.

For the spectra, we have a reference trace with no AO path, a trace with "Plus" polarity on the CM board which started to show a peak when the value of the MC IN2 slider was at about -6 dB, and a trace with "Minus" polarity, which started to show a peak when the value of the MC IN2 slider was at about -16 dB. 

Yarm_CMlocking_spectra_30Apr2014_copy.pdf

We took loop measurements for each of the Plus and Minus cases. Something that seems a little weird is how shallow of a slope we have in both cases near our UGF.

Yarm_CMlocking_TFs_30Apr2014_copy.pdf

 

  9889   Thu May 1 03:23:07 2014 ericqUpdateLSCYarm locking with CM board

Quote:

POY is going from its demod board to the CM board, and then the slow output of that is going to the POY channel of the whitening, and then on to the ADC.  So, with no AO path engaged, this is basically like regular Yarm locking.  

Just to be clear, the normal POY signals are not currently present, so the restore POY script will not result in the arm locking. POY11_I is turned off, POY11_Q is the output of the CM board, which can be used to lock the arm, as we did tonight. 

The POY digital demos angle went -56 -> 90, to get all of POY11_Q_IN1 to POY11_I_ERR

Miscellaneous things:

  • Right now, the cable from CM board ->MC board is a BNC. There appeared to be a differential 2-pin lemo hanging around for this purpose, but it didn't seem to be transmitting the signal. However, we will want something better than a BNC to keep this signal clean. 
  • I took SR785 TFs of the CM board from IN to the slow and fast outs. They looked reasonable, and will be posted in time. 
  • We enabled the 79:1.6k filter in the CM screen (though it is unclear if these are the actual values...), and put in its inverse in the digital path. I.e. we only want this shape in the AO path, to give it 1/f shape in the vicinity of the crossover. This is only necessary in the uncoupled cavity case. 
  9893   Thu May 1 16:41:35 2014 ericqUpdateLSCYarm locking with CM board

 (Edited this post; Forgot to account for the FMs other than 4 and 5... it now agrees better!)

I did some quick MATLAB simulation of the relevant loops to try and understand what was going on. I put the digital UGF around 200Hz, and then brought in the AO path with both signs. 

In these plots, blue is digital only, green is AO+digital with the crossover happening at the UGF, and red is the AO gain set to five times of what it was in the green curve. 

 AOsignsSame.pdfAOsignsOpposite.pdf

Based on the phase curves in the loop measurements, I would be inclined to say the pink -AO case corresponds to the opposite sign plot, and the +AO case to the same sign plot. 

This correspondence also holds for the appearance of the peaks in the noise curves, the Opposite sign case has a dip in loop gain at ~50Hz (pink curve, -AO), same sign around ~30Hz (brown curve, +AO). 

However, both of these look like they become unstable at some point in the transition! This agrees with our experience last night...

I'll fiddle around and try to come up with some compensating digital filter that will make the Opposite sign scenario work. 

The MATLAB code I used to make these plots is attached. 

  9894   Thu May 1 17:00:05 2014 ranaUpdateLSCYarm locking with CM board

 I think that's about halfway there. Since this needs to be a precise comparison, we cannot use so many approximations.

We've got to include the digital AA and AI filters as well as the true, measured, time delay in the system. Also the measured/fitted TF of the CM board with the 79:1.6k filter engaged. We want an overall phase accuracy between Jenne's measured TF from last night and this model (i.e. on the same plot with the residual plotted).

Is there a cavity pole in the model? Should be at ~1.6 kHz.

  7073   Wed Aug 1 18:20:58 2012 JamieUpdateLSCYarm recovered

[Jenne, Jamie]

We recovered lock and alignment of the Y arm.  TRY_OUT is now at ~0.9, after tweaking {I,E}TMY pit/yaw and PZT2.  YARM_GAIN is 0.1.

I saved ITMY, ETMY, and PZT2 alignments in the IFO_ALIGN screen with the new alignment save/restore stuff I got working.

Working on getting Yarm ASS working now...

  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.

  3362   Wed Aug 4 20:15:07 2010 JenneUpdatePEMYay! Guralps work again!

After much hassle, the Guralp cable from the ADC Out of the breakout box to the ADC is fixed, and everything is plugged in and working again.  The seismometers are back in their regular positions at the ends of the MC, ready for some excellent seis/MC combo data. 

I solidified the change of putting the Gur2Z channel into a different BNC input on the ADC.  The C1ADCU_PEM.ini file has been changed so that what used to be the Ranger's channel is now recognized as Gur2Z. 

Also, I changed the same .ini file to reflect Koji's move of ACC_MC1_Z to the old AUDIO_MIC2 channel, so now all 6 Accelerometer channels have the same calibrations again.

Another big change is the change from old-left-handed convention to new-right-handed convention.  The seismometers are aligned the same way they always have been (with the North-South markers aligned with the MC), but now the North-South output is plugged into the BNC on the ADC that is associated with Gur*_X, and the East-West output is plugged into the ADC channel associated with Gur*_Y.  This is true for both Guralp Seismometers. 

So, now we have:

Gur1_X = Gur1_NS = ADC#10

Gur1_Y = Gur1_EW = ADC#11

Gur1_Z = Gur1_Vert = ADC#12

Gur2_X = Gur2_NS = ADC#2

Gur2_Y = Gur2_EW = ADC#3

Gur2_Z = Gur2_Vert = ADC#24

SEIS_Ranger_Y = no longer in the .ini file

  8291   Thu Mar 14 04:20:54 2013 JenneUpdateGreen LockingYbeat attempt

I dedicated my evening to trying to get the Ygreen beatnote (the idea being to then get the Xgreen beatnote).

First up was tweaking up the green alignment.  Per Yuta's suggestion, elog 8283, I increased the refl PD gain by 2 clicks (20dB) to keep the lock super stable while improving the alignment.  After I finished, I turned it back to its nominal value.  I discovered that I need lenses in front of the DC PD (for Ygreen, and I'm sure Xgreen will be the same).  The beam is just barely taking up the whole 2mm diode, so beam jitter translates directly to DC power change measured by the diode.  I ended up going just by the green transmission camera for the night, and achieved 225uW of Ygreen on the PSL table.  This was ~2,000 counts, but some of the beam is always falling off the diode, so my actual counts value should be higher after installing a lens. 

I then opened up the PSL green shutter, which is controlled by the button labeled "SPS" on the shutter screen - I will fix the label during some coffee break tomorrow.  Using my convenient new PSL green setup, removing the DC PD allows the beam to reflect all the way to the fuse box on the wall, so you can check beam overlap between the PSL green and the arm green at a range of distances.  I did this for Ygreen, and overlapped the Ygreen and PSL green. 

I checked the situation of the beat cabling, since Jamie has the beatbox out for whitening filter modifications tonight.  In order to get some signal into the control room, I connected the output of the BBPD amplifier (mounted on the front of the 1X2 rack) directly to the cable that goes to the control room.  (As part of my cleanup, I put all the cables back the way I found them, so that Jamie can hook everything back up like normal when he finishes the beatbox.) 

I then started watching the signal on the 8591E analyzer, but didn't magically see a peak (one can always hope....).

I decided that I should put the offset in the Y AUX laser slow servo back to the value that we had been using for a long time, ~29,000 counts.  This is where things started going south.  After letting that go for a minute or two, I thought to go check the actual temperature of the laser head.  The "T+" temperature on the controller read something like 42C, but the voltmeter which reads a voltage proportional to the temp (10C/V) was reading 5.6V.  I immediately turned off the offset, but it's going to take a while for it to cool down, so I'll come back in the morning.  I want the AUX laser to be something like 34C, so I just have to wait.  Ooops.

Still to do (for the short-term FPMI):

* Find Y beatnote.

* Align Xgreen to the arm - it's still off in pitch.

* Align Xgreen and PSL green to be overlapped, hitting the BBPD.

* Find the X beatnote.

* Reinstall the beatbox.

* Use ALS to stabilize both arms' lengths.

* Lock MICH with AS.

* Look at the noise spectrum of AS - is there more noise than we expect (Yuta and Koji saw extra noise last summer), and if so, where does it come from?  Yuta calculated (elog 6931) that the noise is much more than expected from just residual arm motion.

* Write a talk.

  15122   Wed Jan 15 08:55:14 2020 gautamUpdateCDSYearly DAQD fix

Summary:

Every new year (on Dec 31 or Jan 1), all of the realtime models will report a "0x4000" error. This happens due to an offset to the GPStime driver not being updated. Here is how this can be fixed (slightly modified version of what was done at LASTI).

Steps to fix the DC errors:

  1. ssh into FB machine. 
  2. Edit the file /opt/rtcds/rtscore/release/src/include/drv/spectracomGPS.c:
    • Look for the code block with a text string that reads something like
      /* 2019 had 365 days and no leap seconds */
                   pHardware->gpsOffset += 31536000;
    • Copy and paste the above string for the appropriate number of years of offset you are adding, and edit the comment string appropriately!.
  3. Navigate to /opt/rtcds/rtscore/release/src/drv/symmetricom. Run the following commands:
    sudo make
    sudo make install
  4. Stop all the daqd processes and reload symmetricom:
    sudo systemctl daqd_* stop
    sudo modprobe -r symmetricom
    sudo modprobe symmetricom
  5. Re-start the daqd processes:
    sudo service daqd_* start

Independent of this, there is a 1 second offset between the gpstimes reported by /proc/gps and gpstime. However, this doesn't seem to drift. We had effected a static offset to correct for this in the daqd config files, and it looks like these do not need to be updated on a yearly basis. All the daqd indicators are now green, see Attachment #1.

  16546   Thu Jan 6 12:52:49 2022 AnchalUpdateCDSYearly DAQD fix 2022!

Just as predicted, all realtime models reported "0x4000" error. Read the parent post for more details. I fixed this by following the instructions. I add folowing lines to the file /opt/rtcds/rtscore/release/src/include/drv/spectracomGPS.c in fb1:

/* 2020 had 366 days and no leap second */
       pHardware->gpsOffset += 31622400;
/* 2021 had no leap seconds or leap days, so adjust for that */
       pHardware->gpsOffset += 31536000;

Then is made the package and reloaded it after stoping the daqd services. This brought back all the fast models except C1SUS2 models which are in red due to some other reason that I'll investigate further.

 

  16547   Thu Jan 6 13:54:28 2022 KojiUpdateCDSYearly DAQD fix 2022!

Just restarting all the c1sus2 models fixed the issue. (Attachment 1)

SUS2 ADC1 CH21 is saturated. I'm not yet sure if this is the electronics issue or the ADC issue.
SUS2 ADC1 CH10 also has large offset. This should also be investiagted.

  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.

  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.

 

  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.

  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 !
  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.
  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?

  14265   Fri Nov 2 09:47:57 2018 SteveMetaphysicsTreasureZojirushi is dead

     It took at least ten years to rust away. crying

  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.

  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.

  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.

  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.

ELOG V3.1.3-