40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
 40m Log, Page 146 of 344 Not logged in
ID Date Author Type Category Subject
14777   Fri Jul 19 15:51:55 2019 gautamUpdateGeneralProjector lightbulb blown out

[chub, gautam]

Bulb replaced. Projector is back on.

14778   Fri Jul 19 15:54:47 2019 gautamUpdateGeneralControl room UPS Batteries need replacement

The control room UPS started making a beeping noise saying batteries need replacement. I hit the "Test" button and the beeping went away. According to the label on it, the batteries were last repalced in March 2016, so maybe it is time for a replacement, @Chub, please look into this.

14780   Fri Jul 19 17:42:58 2019 gautamUpdateGeneralrossa Xdisp bricked

For some reason, rossa's Xdisplay won't start up anymore. This happened right after the UPS reset. Koji and I tried ~1.5 hours of debugging, got nowhere.

14784   Sat Jul 20 11:24:04 2019 gautamUpdateGeneralrossa bricked

Summary:

SnapPy scripts made to work on Pianosa.

Details:

Of course rossa was the only machine in the lab that could run the python scripts to interface with the GigE camera. And it is totally bricked now. Lame.

So I installed several packages. The key was to install pypylon - if you go to the basler webpage, pypylon1.4.0 does not offer python2.7 support for x86_64 architecture, so I installed pypylon1.3.0. Here are the relevant lines from the changelog:

gstreamer-plugins-bad-0.10.23-5.el7.x86_64    Sat 20 Jul 2019 11:22:21 AM PDT gstreamer-plugins-good-0.10.31-13.el7.x86_64  Sat 20 Jul 2019 11:22:11 AM PDT gstreamer-plugins-ugly-0.10.19-31.el7.x86_64  Sat 20 Jul 2019 11:20:08 AM PDT gstreamer-python-devel-0.10.22-6.el7.x86_64   Sat 20 Jul 2019 10:34:35 AM PDT pygtk2-devel-2.24.0-9.el7.x86_64              Sat 20 Jul 2019 10:34:34 AM PDT pygobject2-devel-2.28.6-11.el7.x86_64         Sat 20 Jul 2019 10:34:33 AM PDT pygobject2-codegen-2.28.6-11.el7.x86_64       Sat 20 Jul 2019 10:34:33 AM PDT gstreamer-devel-0.10.36-7.el7.x86_64          Sat 20 Jul 2019 10:34:32 AM PDT gstreamer-python-0.10.22-6.el7.x86_64         Sat 20 Jul 2019 10:34:31 AM PDT gtk2-devel-2.24.31-1.el7.x86_64               Sat 20 Jul 2019 10:34:30 AM PDT libXrandr-devel-1.5.1-2.el7.x86_64            Sat 20 Jul 2019 10:34:28 AM PDT pango-devel-1.42.4-1.el7.x86_64               Sat 20 Jul 2019 10:34:27 AM PDT harfbuzz-devel-1.7.5-2.el7.x86_64             Sat 20 Jul 2019 10:34:26 AM PDT graphite2-devel-1.3.10-1.el7_3.x86_64         Sat 20 Jul 2019 10:34:26 AM PDT pycairo-devel-1.8.10-8.el7.x86_64             Sat 20 Jul 2019 10:34:25 AM PDT cairo-devel-1.15.12-3.el7.x86_64              Sat 20 Jul 2019 10:34:25 AM PDT mesa-libEGL-devel-18.0.5-3.el7.x86_64         Sat 20 Jul 2019 10:34:24 AM PDT libXi-devel-1.7.9-1.el7.x86_64                Sat 20 Jul 2019 10:34:24 AM PDT pygtk2-doc-2.24.0-9.el7.noarch                Sat 20 Jul 2019 10:34:23 AM PDT atk-devel-2.28.1-1.el7.x86_64                 Sat 20 Jul 2019 10:34:21 AM PDT libXcursor-devel-1.1.15-1.el7.x86_64          Sat 20 Jul 2019 10:34:20 AM PDT fribidi-devel-1.0.2-1.el7.x86_64              Sat 20 Jul 2019 10:34:20 AM PDT pixman-devel-0.34.0-1.el7.x86_64              Sat 20 Jul 2019 10:34:19 AM PDT libXinerama-devel-1.1.3-2.1.el7.x86_64        Sat 20 Jul 2019 10:34:19 AM PDT libXcomposite-devel-0.4.4-4.1.el7.x86_64      Sat 20 Jul 2019 10:34:19 AM PDT libicu-devel-50.1.2-15.el7.x86_64             Sat 20 Jul 2019 10:34:18 AM PDT gdk-pixbuf2-devel-2.36.12-3.el7.x86_64        Sat 20 Jul 2019 10:34:17 AM PDT pygobject2-doc-2.28.6-11.el7.x86_64           Sat 20 Jul 2019 10:34:16 AM PDT pygtk2-codegen-2.24.0-9.el7.x86_64            Sat 20 Jul 2019 10:34:15 AM PDT

Camera server is running on a tmux session on pianosa. But it keeps throwing up some gstreamer warnings/errors, and periodically (~every 20 mins) crashes. Kruthi tells me that this behavior was seen on Rossa as well, so whatever the problem is, doesn't seem to be because I missed out on installing some packages on pianosa. Moreover, if the server is in fact running, I am able to take a snapshot - but the camera client does not run.

14794   Sun Jul 21 22:16:34 2019 ranaUpdateGeneralrossa Xdisp bricked

"bricked" is to mean that it has the functionality of a brick and can be tossed. But rossa seems to have just gotten some software config corruption. I spent a couple hours reinstalling SL7 today as per my previous elog notes and the X display seems to work as before.

i.e. it was fine with the default setup, except for the ole "X chrashes if the mouse goes to left side of screen". As before, I

1. blacklisted the nouvaeu driver (which is used by default)
3. run its installation from the no-X terminal

left side of screen is safe again

This time I installed SL7.6 and followed the K Thorne wiki. But its having trouble installing cds-root because it can't find root.

14826   Sun Aug 4 14:39:41 2019 gautamUpdateGeneralsome lab activity
1. Unresponsive c1psl, c1iool0, c1auxey and c1iscaux VME crates were keyed.
2. c1psl channels were burt-restored, did a burtrestore, and re-locked the PMC. Tweaked the pointing into the PMC on the PSL table to increase the PMC transmission from ~0.69 to ~0.71.
3. Re-locked IMC. Ran WFS offset script to relieve the ~100 DAC counts (~10 urad) DC offset from the WFS servos to the IMC suspensions (a serious calibration of this into physical units should be made part of the planned 40m WFS activity). Now that I think about it, since we change the IMC alignment to match the input beam alignment, some post-IMC clipping could modulate the power incident on the ITMs, which is a source of error for the arm cavity loss determination using DC reflection. We need a better normalizing data stream than the IMC transmission.
4. The IFO_OVEREVIEW medm screen was modified such that the threshold for the PMC transmitted beam to be visible was lowered from 0.7 to 0.6, so that now there is a continuous beam line from the NPRO to the PRM when the IMC is locked even when the PMC transmission degrades by 5% due to thermally driven pointing drifts on the PSL table.
5. The wmctrl utility on pianosa wasn't working so well, I wasn't able to use my usual locking MEDM autoconfig scripts. Turned out to be due to a zombie MEDM window which I killed with xkill, now it is working okay again.
6. The misaligned XARM was re-aligned and the loss measuring PDA520 at the AS port was removed from the beam path (mainly to avoid ADC saturations the fringing Michelson will cause).
7. I noticed that the ETMX Oplev HeNe SUM level has degraded to ~50% of its power level from 200 days ago [Attachment #1], may need a new HeNe here soon. @Chub, do we have spare HeNes in stock?

I want to collect some data with the arms locked to investigate the possibility/usefullness of having seismic feedforward implemented for the arms (it is already known to help the IMC length and PRC angular stability at low frequencies). To facilitate diagnostics I modified the file /users/Templates/Seismic/Seismic_vs_TRXTRYandMC.xml to have the correct channel names in light of Lydia's channel name changes in 2016. Looking at the coherence data, the alignment of the cartesian coordinate system of the Seismometers at the ends and the global interferometer coordinate system can be improved.

I don't know if for the MISO filter design if there is any difference in using TRX/TRY as the target, or the arm length control signal.

Data collection started at 1249018179. I've setup a script running in a tmux shell to turn off the LSC enable in 2 hours.

14881   Mon Sep 16 12:00:16 2019 aaronHowToGeneralMoved some immovable optics

When I put away the lenses we had used for measuring the RF transfer functions of the QPD heads, I saw that I'd removed them from the cabinet containing green endtable optics, but hadn't noticed the sign forbidding their removal. I'll talk with Koji/Gautam about what happened and what should be done.

14919   Tue Oct 1 18:35:12 2019 gautamUpdateGeneralBeam centering campaign
1. With TRX and TRY maximized using ASS, I centered the Oplev spots on the respective QPDs for the four test masses and the BS. I also centered the spot onto the IPPOS QPD by moving the available steering mirror.
2. At EX, I tweaked the input pointing of the green beam into the arm by manually twiddling with the PZT mirrors. I was able to get GTRX~0.4.
3. On the AS table - Koji and I found that there was a steering mirror placed in the AS beam path such that there was no light reaching the AS110 or AS55 PDs. Please - when you are done with your measurement, return the optical configuration to the state it was in before so that the usual locking activity isn't disturbed by a needless few hours troubleshooting electronics.

Once Koji is done with his checkout of the whitening electronics, I will try and lock the PRMI.

14930   Thu Oct 3 12:08:47 2019 gautamUpdateGeneralMake the Jenne-laser setup fiber-coupled

I propose the following re-organization of the PDFR measurement breadboard. We have all the parts on hand, just needs ~30mins of setup work and some characterization afterwards. The fiber beamsplitter will not be PM, but for this measurement, I don't think that matters (the patch fiber from the diode laser head isn't PM anyways). We have one spare 1 GHz BW NF1611 that is fiber coupled (used to live on the ITMY in-air table, and is (conveniently) labelled "REF DET", but I'm not sure what the function of this was). In any case, we have at least 1 free-space NF1611 photodiode available as well. I suggest confirming that the FC version works as expected by calibrating against the free space PD first.

Update 245pm: Implemented, see Attachment #2. Aaron is testing it now, and will post the characterization results.

14931   Thu Oct 3 14:32:37 2019 ranaUpdateGeneralMake the Jenne-laser setup fiber-coupled

I'm curious to see if we really need the 1611, or if we can calibrate the diode laser vs. the 1611 one time and then just use that calibration to get the absolute cal for the DUT.

14932   Thu Oct 3 14:54:33 2019 KojiUpdateGeneralMake the Jenne-laser setup fiber-coupled

I'm afraid that the RF modualtion of the laser is nonlinear and the electrical and optical resoponse is dependent on the LD pumping current and RF input power. So I feel safe if we keep the reference PD. Of course, this is my feeling and it should be quantitatively tested.

14934   Thu Oct 3 21:05:04 2019 aaronUpdateGeneralMake the Jenne-laser setup fiber-coupled

I measured the RF response of the fiber-coupled NewFocus 1611, calibrating out the cable delay. The laser current was set to 20.0 mA, and the RF power going into the splitter was -10 dBm. The DC voltage was 1.87 V, and Gautam and I measured the power from the fiber at 344uW.

Something still looks very wrong -- the PD is supposed to be flat out to 1GHz, and physical units pending, need food.

14936   Thu Oct 3 23:15:39 2019 KojiUpdateGeneralMake the Jenne-laser setup fiber-coupled

The 1GHz PD has a bit more flat response, but the laser and the driving network have more frequency dependence as you saw.

14937   Fri Oct 4 00:30:31 2019 gautamUpdateGeneralMake the Jenne-laser setup fiber-coupled

I think the metric of interest here is the consistency of the AC transimpedance of the proposed new "Reference PD" (= fiber coupled NF1611) vs the old reference (free space NF1611), since everything will be calibrated against that.

 Quote: Something still looks very wrong -- the PD is supposed to be flat out to 1GHz, and physical units pending, need food.
14940   Fri Oct 4 14:25:59 2019 aaronUpdateGeneralMake the Jenne-laser setup fiber-coupled

## Summary:

The fiber-coupled PD seems to have a factor of ~1.5 difference in responsivity compared to the free-space PD. There are some differences in the two ways I made the measurement that I don't yet understand.

## Details

I measured relative responsivities of the fiber and free coupled NewFocus 1611 PDs (scaled by the Jenne AM transfer function).

I made the measurement in two ways, see attachment threeIn attachment oneI show the response for separately measuring the two PDs relative to a pickoff of the source (two-port thru calibration). In attachment two I measure the relative responses directly, without picking off a reference (three-port calibration). I scaled the transfer functions by their DC voltages; both PDs have transimpedances of 700 V/A.

However, there are some clear differences in the response (overall factor of 0.5dB offset that may be explained by a miscalibrated DC level; apparent periodicity in attachment 1) that I don't yet understand.The free path of the non-fiber PD is ~5-6 inches, which accounts for the ~45 degrees of phase advance of the fiber relative to free coupled PD signal. (12.7cm / (c / 300 MHz) * 360 degrees ~ 45 degrees)

I didn't find Agilent's manual very helpful for learning about the available calibration schemes, and didn't find a resource online that I liked -- is there a good one?
I think I want to characterize the WFS heads treating the DUT as a three-port device (AM in, ref PD, WFS segment PD).
14964   Thu Oct 10 23:36:02 2019 KojiUpdateGeneralWednesday cleaning work

[Jon, Yehonathan, Gautam, Aaron, Shruti, Koji]

We get together on Wednesday afternoon for cleaning the lab. Particularly, we collected e-wastes: VME crates, VME modules, old slow control cables, and other old/broken electronics. They are piled up in the office area and the cage outside rioght now (Attachments 1/2). We asked Liz to come to pick them up (under the coordination with either Gautam or Koji). Eventually this will free up two office desks.

Also, we made the acromag components organized in plastic boxes. (Attachment 3)

14969   Mon Oct 14 17:24:28 2019 gautamUpdateGeneralWorkstation computers taken off UPS (temporarily)

The UPS is now incessantly beeping. I cannot handle this constant sound so I shut down all the control room workstations and moved the power strip hosting the 4 CPUs to a wall socket for tonight. Chub and I will replace the UPS batteries tomorrow.

14971   Tue Oct 15 17:19:38 2019 KojiUpdateGeneralWednesday cleaning work

[Liz, Gautam, Chub, Jordan, Koji]

We removed a significant amount of e-waste from the lab. The garbage was moved to the e-waste station in WB SB and are waiting for disposal.

14972   Tue Oct 15 17:22:26 2019 gautamUpdateGeneralWorkstation computers back on UPS

Batteries + power cables replaced, and computers back on UPS from today ~3pm.

 Quote: The UPS is now incessantly beeping. I cannot handle this constant sound so I shut down all the control room workstations and moved the power strip hosting the 4 CPUs to a wall socket for tonight. Chub and I will replace the UPS batteries tomorrow.
14975   Thu Oct 17 12:34:51 2019 gautamUpdateGeneralDaytime wishlist

Some ideas that would help increase the locking duty-cycle in the short term.

1. Seismometer investigation - something is not quite right with the vertex seismometer. This is the one that is primarily used for feedforward, and can be really helpful.
2. Drifting TTs - it is really annoying to have to re-set the input pointing into the interferometer every ~ hour. See Attachment #1.
3. FSS - this isn't a scientific statement, but there were ~20-30 minute periods last night where the PC drive RMS was displaying sharp spikes repeating every 2-3 seconds, first with increasing and then decreasing height. This is a new feature to me in the long standing PC drive saga but it doesn't tell me exactly what is going on as I don't know in what frequency band the glitch is actually happening. See Attachment #2.
4. ALS noise - while it is possible now to routinely transition the arm length control from the POX/POY to CARM/DARM basis, I see some sharp (<0.1 s) dives in the TRX/TRY levels when the arms are under ALS control. This wasn't present a week ago. Needs to be investigated - I defer this to the daytime tomorrow.
15069   Tue Dec 3 22:41:17 2019 shrutiUpdateGeneralPLL for PM measurement

I worked on the setup up for the phase modulation measurement of the X end NPRO PZT. A previous similar measurement can be found here (12077). The setup was assembled based on the schematic in Attachment1.

Mixer used: Level 7, Mini circuits ZP-3+
LPF: up to 1.9MHz

Cables exiting the PSL table:
1. LO (Marconi -> Mixer)
2. RF (PSL+X beat note -> Mixer) The cable for this was taken from the Beat Mouth (otherwise connected to the oscilloscope)
3. Ext modulator (SR560 -> Marconi)

The long cable labled 'X Green Beat' was used to connect to the PZT (from the network analyzer).

Observations: The beat note kept floating between 0 and ~100 MHz

The PLL part of the circuit was tested coarsely with the spectrum analyzer function of the Agilent, where the loop was seen to stabilize when the carrier frequency of the Marconi was close to the instantaneous beat frequency.

15074   Wed Dec 4 20:32:43 2019 gautamUpdateGeneralPLL for PM measurement

Were some cables from the ALS beat setup modified? I can't see the beat on the scope, and this elog doesn't say anything about cable connection rearrangement. At ~2311, I am reverting the setup to as it should be.

15077   Thu Dec 5 14:54:15 2019 gautamUpdateGeneralSymlink to SRmeasure and AGmeasure

I symlinked the SRmeasure and AGmeasure commands to /usr/bin/ on donatella (as it is done on pianosa) so that these scripts are in \$PATH and may be run without having to navigate to the labutils directory.

15088   Mon Dec 9 21:22:46 2019 shrutiUpdateGeneralPLL / PM measurement of Xend NPRO PZT

### In short:

Using the same setup as before with a LPF changed to have a cutoff of 5 MHz, the PLL was implemented and a TF measurement of the phase modulation was attempted. But, the beatnote drift was too high to get a prolonged phase lock (many times over 5MHz in <5 min).

### Steps undertaken:

1. Normally I would unlock the IMC (Disabling the servo between the 'Filter' and 'Polarity' on the Mode Cleaner Servo Screen), but today I did not have to since Rana had kept it unlocked.

2. Misaligned the ITMX. This is to prevent cavity resonances from returning to the laser

3. Turned up the air on the HEPA at the PSL table to 100% during the measurement

4. Cables were connected as before (diagram shown in attachment of elog 15069)

5. The X end laser NPRO was actuated for the TF measurement using a long cable connected to TO AUX_X LASER PZT

### Thoughts and observations:

- Reading out the error signal after amplification cannot distinguish between a locked loop or one out of its range. The error signal would be very small in both cases.

- Looking at the beat note on an oscilloscope, there also seemed to be an additional amplitude modulation that I had not noticed earlier. Rana suggested that it may have something to do with the pre-mode cleaner and the AOM being driven at 80 MHz

- Even though the TF was attempted, it seemed too noisy, suggesting that the PLL did not seem to work

- Rana also suggested that it may be a better idea to use the PZT of one of the lasers as the VCO for the PLL feedback instead of the Marconi.

 Quote: I worked on the setup up for the phase modulation measurement of the X end NPRO PZT. A previous similar measurement can be found here (12077). The setup was assembled based on the schematic in Attachment1. Mixer used: Level 7, Mini circuits ZP-3+ LPF: up to 1.9MHz Cables exiting the PSL table: 1. LO (Marconi -> Mixer) 2. RF (PSL+X beat note -> Mixer) The cable for this was taken from the Beat Mouth (otherwise connected to the oscilloscope) 3. Ext modulator (SR560 -> Marconi) The long cable labled 'X Green Beat' was used to connect to the PZT (from the network analyzer). Observations: The beat note kept floating between 0 and ~100 MHz The PLL part of the circuit was tested coarsely with the spectrum analyzer function of the Agilent, where the loop was seen to stabilize when the carrier frequency of the Marconi was close to the instantaneous beat frequency.

15101   Tue Dec 17 20:08:09 2019 shrutiUpdateGeneralPLL / PM measurement of Xend NPRO PZT

## 1. Some calculations

For a Unity Gain Frequency (UGF) of 1 kHz, assumed PZT response $K_{VCO}$ of 1 MHz/V, Mixer response $K_{M}$ of 25 mV/$\pi$ rad, the required gain of the amplifier is

$G = 2 \pi \times \text{UGF}/ (K_{VCO} K_M)$

G ~ 0.8

## 2. Progress

- Measured the mixer response

### Measuring mixer response:

- PSL laser temperature was adjusted so that beat frequency was roughly 25 MHz and the amplitude was found to be roughly -30dBm.

- At the RF port instead of the beat signal, a signal of 25 MHz + few kHz at -30 dBm was inputted. The LO was a 25 MHz signal was sent from the Marconi at 7 dBm.

- The mixer output was measured, with setup as in Attachment 1  Figure (A), on an oscilloscope. The slope near the small angle region of the sine curve would be the gain (in V/rad) and was found to be: $K_M \approx 25 \text{ mV}/ \pi$ rad

- Since from the above calculations it seemed like an amplifer gain of 1 should work for the PLL, I rearranged the set up as in Figure (B) of Attachment 1 to actuate the X end NPRO PZT, I adjusted the PSL temperature (slow control) to try and match the frequency to 25 MHz, but couldn't lock the loop. I was monitoring the error signal after amplification (50 ohm output of the SR 560) which showed oscillations when the beat frequency was near 25 MHz and nothing significant otherwise.

- I used a 20 dB attenuator at the amplifier output and saw the beat note oscillate for longer, but maybe because it was a 50 ohm component in a high impedance channel it did not work either (?). I tried other attenuator combinations with no better luck.

- Is there a better location to add the attenuator? Should I pursue amplifying the beat signal instead?

- Also, it seemed like the beat note drift was higher than earlier. Could it be because the PMC was unlocked?

 Quote:

15121   Tue Jan 14 20:17:09 2020 gautamSummaryGeneralIFO recovery

Summary:

There was no light entering the IFO. I worked on a few things to bring the interferometer to a somewhat usable state. The goal is to get back to PRFPMI locking ASAP.

Details:

Problem: All fast models report a "0x4000" DC error. See Attachment #1.

Solution: I think this is a "known" issue that happened last new year too. The fix was to add a hard-coded 1 second offset to the daqd config files. However, incrementing/decreasing this offset by +/- 1 second did not fix the errors for me today. I'll reach out to JH for more troubleshooting tips.

Update 15 Jan 2020 830am: The problem is now fixed. See here.

Problem: c1susaux and c1auxey were unresponsive.

Solution: Keyed c1auxey. Rebooted c1susaux and as usual, manually started the eth0/eth1 subnets. The Acromag crate did not have to be power-cycled. ITMY got stuck in this process - I released it using the usual bias jiggling. Why did c1susaux fail? When did it fail? Was there some un-elogged cable jiggling in that part of the lab?

Problem: IMC autolocker and FSS slow processes aren't running on megatron after the upgrade.

Solution: Since no one bothered to do this, I setup systemd infrastructure for doing this on megatron. To run these, you do:

sudo systemctl start MCautolocker.service
sudo systemctl start FSSSlow.service

and to check their status, use:

sudo systemctl status MCautolocker.service
sudo systemctl status FSSSlow.service

The systemd setup is currently done in a naive way (using the bash executable to run a series of commands rather than using the systemd infrastructure itself to setup variables etc) but it works. I confirmed that the autolocker can re-acquire IMC lock, and that the FSS loop only runs when the IMC is locked. I also removed the obsolete messages printed to megatron's console (by editing /etc/motd) on ssh-login, advising the usage of initctl - the updated message reflects the above instructions.

In order to do the IMC locking, I changed the DC voltage to the AOM to +1V DC (it was +0.8 V DC). In this setting, the IMC refl level is ~3.6 V DC. When using the undiffracted AOM beam, we had more like +5.6 V DC (so now we have ~65% of the nominal level) from the IMC REFL PD when the IMC was unlocked. IIRC, the diffraction efficiency of the AOM should be somewhat better, at ~85%. Needs investigation, or better yet, let's just go back to the old configuration of using the undiffracted beam.

There was also an UN-ELOGGED change of the nominal value of the PMC servo gain to 12.8, and no transfer function measurement. There needs to be a proper characterization of this loop done to decide what the new nominal value should be.

I'm going to leave the PSL shutter open and let the IMC stay locked for stability investigations. Tomorrow, I'll check the single-arm locking and the ALS system.

15123   Wed Jan 15 10:04:19 2020 gautamSummaryGeneralPOX / POY locking restored

Single arm locking using POX and POY has been restored. After running the dither alignment servos, the TRX/TRY levels are ~0.7. This is consistent with the IMC transmission being ~11000 counts with the AOM 1st order diffracted beam (c.f. 15000 counts with the undiffracted beam).

 Quote: Tomorrow, I'll check the single-arm locking and the ALS system.
15128   Wed Jan 15 16:54:51 2020 gautamUpdateGeneralPDA10CF removed from AS table

Per Yehonathan's request, I removed one PDA10CF from a pickoff of REFL on the AS table (it was being used for the mode spectroscopy project). I placed a razor beam dump where the PD used to be, so that when the PRM is aligned, this pickoff is dumped. This is so that team ringdowns can use a fast PD.

15129   Thu Jan 16 19:32:23 2020 shrutiUpdateGeneralPLL / PM measurement of Xend NPRO PZT

With Gautam's help today the PLL managed to be be locked for a few brief moments. Turns out the signal power of the beat was an issue.

What was changed prior to/ during the experiment:

1. The PSL shutter was closed so not light goes into the input mode cleaner.

2. HEPA turned up (will be turned back down to ~30%)

3. AOM driver offset voltage decreased from 1V to ~100 mV (this will be reverted to 1V by the end of today). This increases the beat signal by deflecting the zeroth order beam to create the beat.

4. Output of servo SR 560 sent to the PZT of the X NPRO laser (the cable was disconnected from the pomona box at the X end)

5. The SR560, mixer, LPF and cables required for connections were moved into the PSL enclosure.

6. The error and control signals were hooked up to the oscilloscope where the beat outputs were visible (the setup has been reverted back to the original).

Elog 14687 has a detailed description of the conditions that provide a stable lock. I was told that the PI controller (LB1005) may be a better servo than the SR560, but today it was not used.

1) Parameters during the more successful attempts:

LPF: 5 MHz, Mixer: ZP-3+

Gain set at SR560: varied, but generally 200

Filter at SR560: 1 Hz low pass (single pole? at least by the label)

2) The LO had to be very close (<2 MHz) to the beat frequency in order to achieve a lock for ~30s

gautam edits:

• the error signal for the PLL was being sourced from the 20dB coupled port on the BeatMouth.
• additionally, most of the power in the PSL beam coupled into the fiber was being deflected into the first order beam by team ringdown.
• The Vpp of the mixer output (when using the coupled beat and low PSL beam power) was a paltry 5-10 mVpp .
• I suggested using the direct NF1611 output for this measurement instead of the coupled output (alternatively, use an amp). it's probably also better to use the LB1005 for locking the PLL, long term, this can be set up to be controlled remotely, and a slow PID servo can be used to extend the duration of the lock by servoing either the marconi carrier freq or the EX temp ctrl.
Quote:

## 1. Some calculations

For a Unity Gain Frequency (UGF) of 1 kHz, assumed PZT response $K_{VCO}$ of 1 MHz/V, Mixer response $K_{M}$ of 25 mV/$\pi$ rad, the required gain of the amplifier is

$G = 2 \pi \times \text{UGF}/ (K_{VCO} K_M)$

G ~ 0.8

## 2. Progress

- Measured the mixer response

### Measuring mixer response:

- PSL laser temperature was adjusted so that beat frequency was roughly 25 MHz and the amplitude was found to be roughly -30dBm.

- At the RF port instead of the beat signal, a signal of 25 MHz + few kHz at -30 dBm was inputted. The LO was a 25 MHz signal was sent from the Marconi at 7 dBm.

- The mixer output was measured, with setup as in Attachment 1  Figure (A), on an oscilloscope. The slope near the small angle region of the sine curve would be the gain (in V/rad) and was found to be: $K_M \approx 25 \text{ mV}/ \pi$ rad

- Since from the above calculations it seemed like an amplifer gain of 1 should work for the PLL, I rearranged the set up as in Figure (B) of Attachment 1 to actuate the X end NPRO PZT, I adjusted the PSL temperature (slow control) to try and match the frequency to 25 MHz, but couldn't lock the loop. I was monitoring the error signal after amplification (50 ohm output of the SR 560) which showed oscillations when the beat frequency was near 25 MHz and nothing significant otherwise.

- I used a 20 dB attenuator at the amplifier output and saw the beat note oscillate for longer, but maybe because it was a 50 ohm component in a high impedance channel it did not work either (?). I tried other attenuator combinations with no better luck.

- Is there a better location to add the attenuator? Should I pursue amplifying the beat signal instead?

- Also, it seemed like the beat note drift was higher than earlier. Could it be because the PMC was unlocke

15148   Thu Jan 23 20:08:49 2020 shrutiUpdateGeneralPLL / PM measurement of Xend NPRO PZT

### Setup Update:

- No more SR 560, upgraded to LB1005 P-I controller.  Because: Elog 14687. Schematic of new setup shown in Attachment 1.

- For this, the Marconi was moved to the other (east) side of the PSL table and a power supply was also placed in the enclosure.

I think that the RF power at the mixer in this new configuration is 0 dBm (since the spectrum analyzer read ~ -20 dBm)

### Progress Today:

- Turned up the HEPA to 100%, closed the PSL shutter, misaligned the ITMX, connected the LB1005 to the PZT. [The PZT has been reconnected to the X arm PDH servo, HEPA back to 20-30%]

- Tried to look for the PSL+X beat, but it was not there. Gautam identified the flipmount in the path which sorted it out (eventually), but there was no elog about it.

- After much trial, the loop seemed to lock with PI corner 1 kHz, gain ~2.9 (as read on knob), LFGL set to 90 dB. The beat note looked quite stable on the oscilloscope, but the error signal had an rms of ~100 mV (Rana pointed out that it could be the laser noise) and the lock lasted for ~1 min each time.

The parameters were similar to that in elog 14687. Why do we require such a high PI corner frequency and LFGL?

15158   Mon Jan 27 14:01:01 2020 JordanConfigurationGeneralRepurposed Sorenson Power Supply

The 24 V Sorenson (2nd from bottom) in the small rack west of 1x2 was repurposed to 12V 600 mA, and was run to a terminal block on the north side of 1X1. Cables were routed underneath 1X1 and 1X2 to the terminal blocks. 12V was then routed to the PSL table and banana clip terminals were added.

15169   Tue Jan 28 19:40:15 2020 shrutiUpdateGeneralPLL / PM measurement of Xend NPRO PZT

Over the past few days, I have been trying to make measurements of the phase modulation transfer function by modulating the X end laser PZT via PLL.

The setup was modified every time during the experiment in the same manner as mentioned in elog 15148.

I could not make the PLL lock for long enough to take a proper TF measurement, resulting in TFs that look like Attachment 1. The next step would be to use the method of a delay line frequency discriminator instead of the PLL.

1. I do not understand why the high PI corner frequency of 1kHz or 3kHz was required to lock.
2. The rms level of the error signal when locked was ~100 mV, which is 25% of the total mixer range (~400 mVpp). Decreasing the gain only caused the loop to go out of lock and did not decrease this noise in the error signal.
3. The setup was also partly inside the PSL enclosure, with the HEPA turned to 100%, which is probably a noisy environment for this measurement. Closing and opening the shutters or any disturbance near the enclosure resulted in movement of the beat note up to 5 MHz.
4. It may have been a better idea to actuate the PSL laser instead of the X NPRO because of its larger range, but would this solve the issue with the noise?
15174   Wed Jan 29 12:29:33 2020 shrutiUpdateGeneraldelay line frequency discriminator for PM

Today I began working on a TF measurement based on the delay line frequency discriminator setup in elog 4254 using a single mixer (without the 'I' and 'Q' readout).

For this, I re-organised the setup for the PLL measurement of the transfer function (elog 15148), increasing the HEPA for the initial changes while the PSL door was open, and then reverting it back to ~30%:

• I removed the 20dB coupler and connected the splitter directly after the amplifer to split the beat note signal into two coaxial cables one of which was ~1.5m longer than the other
• The recombined signals were combined in a mixer outside the PSL enclosure. I also replaced the 1.9 MHz LPF with a 5 MHz LPF.
• I used an SR 560 to amplify the signal after the LPF.

With the above setup the power that was seen at each channel of the delay line was <1dBm, which is not ideal for the any of the available mixers.

After the group meeting, I changed the amplifer to ZHL-3A (that is near the beat mouth) instead of a ZFL-500HLN because it had a higher gain (~28dB as opposed to ~19dB of the latter). The power seen at each of the delay line channels is over 5.5 dBm. This is consistent with the estimation 0 dBm beat -> -20 dBm after 20dB coupler -> 8 dBm after amplifier -> 5 dBm after splitter with insertion loss of 3 dB.

Is this sufficient enough for the mixer to work? In Attachment 1: A shows the mixer output (point B in Attachment 2) when the IMC is locked, in B the IMC is unlocked at the middle of the spectrum, and each of the dips show the DC voltage being sent to the PSL temperature servo being decreased by 0.01 V.

Gautam pointed me to the location of a few other RF amplifiers (ZHL-32A+, ZHL-1A) which don't possess a higher gain but can be used without disrupting the ALS related work (I was told).

For shorter duration changes that I made later, I opened and closed the PSL enclosure doors without changing the HEPA.

Attachment 2 shows the current setup as is, but I might add a PSL servo tomorrow to stabilise its frequency corresponding to a null mixer output without driving anything else.

15177   Thu Jan 30 15:24:10 2020 ?UpdateGeneraldelay line frequency discriminator for PM

yes, its fine to use this with a level 3 or level 7 mixer; let's see some PM transfer functions !

 Quote: Is this sufficient enough for the mixer to work?
15180   Thu Jan 30 22:02:42 2020 shrutiUpdateGeneraldelay line frequency discriminator for PM

I could not find any level 3 mixers, but by adjusting the beat frequency the power in each of the delay line channels rose to almost 6.5 dBm.

### Things I did earlier today:

1. Played with the slow servo on the FSS screen, but then reset the parameters to what was there before (Later found out that this was to lock the PSL freq to the IMC when the IMC power is significant.)
2. Connected the AG 4395A to the X PZT
3. Closed the PSL shutter

Transfer function measurement: (Refer Attachment 1)

Everything about the setup remained as I had left it earlier: described in elog 15174

except

• SR560 gain set to 10, DC coupled
• DC block at channel A of Agilent (The measurement was A/R)

I did not use a slow servo, but took individual sweeps adjusting the PSL temperature each time to bring the error voltage between +/-25 mV. The beat frequency was over 100 MHz.

For the plot posted in Attachment 1, the measurement paramters are the following. Will do further measurements/analysis tomorrow.

# AG4395A Measurement - Timestamp: Jan 30 2020 - 21:58:00
# Parameter File: TFAG4395Atemplate.yml
#---------- Measurement Parameters ------------
# Start Frequency (Hz): 50000.0, 50000.0
# Stop Frequency (Hz): 1000000.0, 1000000.0
# Frequency Points: 801, 801
# Measurement Format: LOGM, PHAS
# Measuremed Input: AR, AR
#---------- Analyzer Settings ----------
# Number of Averages: 1
# Auto Bandwidth: Off, Off
# IF Bandwidth: 1000.0, 1000.0
# Input Attenuators (R,A,B): 0dB 0dB 0dB
# Excitation amplitude = -20.0dBm

Quote:

yes, its fine to use this with a level 3 or level 7 mixer; let's see some PM transfer functions !

 Quote: Is this sufficient enough for the mixer to work?
15182   Fri Jan 31 16:57:09 2020 gautamUpdateGeneralMetal PMC parts

Jon brought over a box of parts for constructing the metal PMCs. I have stored it along the Y-arm, on top of the green optics cabinet.

I didn't do an exhaustive inventory check, but the following are the rough contents of the box:

• 41 deg AoI flat mirrors, R=99% @ 1064nm --- 11 pcs
• 6.8 deg AoI curved mirrors --- 5 pcs
• PZTs --- 3pcs
• Metal PMC body --- 2 pcs
• "Baked PZT endcaps" --- 3 pcs
• Ball bearings, clamps, misc hardware

I didn't inspect the optics but since we have so many, I am hoping we can find 3 good quality ones for one cavity at least. We should check that the geometry is suitable for our RF sideband frequencies.

15193   Thu Feb 6 16:14:44 2020 ranaUpdateGeneraloffice area temperature

I changed the office area thermostate near Steve's desk from 68F to 73F today. Please do not change it.

If anyone from facilities comes to adjust something, please put the details in the elog on the same day so that we can know to undo that change rather than chase down other drifts in the system.

15196   Fri Feb 7 02:41:28 2020 KojiUpdateGeneraloffice area temperature

Not sure what's wrong, but the workstation desk is freezing cold again and the room temp is 18degC (64degF).

15197   Fri Feb 7 09:45:03 2020 shrutiUpdateGeneralAM at X end

I took a few AM TF measurements at the X end for which I:

• Misaligned the ITMX (then re-aligned it)
• Opened the X green shutter during the measurements and closed it at the end
• Moved the Agilent from the PSL area to the X end, the delay line and mixer still remains near the PSL area (will move it soon)
• Took a bunch of TFs

I will post the data soon.

15198   Fri Feb 7 12:58:25 2020 YehonathanUpdateGeneralMetal PMC parts

I took the metal PMC box and examined its content and find the following items:

 Name Quantity Picture (Attachment #) Metal PMC body (PMC1) 1 1-3 Metal PMC body with two mounted 41 deg mirrors (PMC2) 1 4-6 "Baked PZT Caps" 3 7 PZT Caps 2 8 Flat mirror mounts 2 9 Bar clamps 4 10 Clamp studs 8 10 PZTs 4 11 ORings INF 12 Ball bearings INF 13 6.8 deg AoI curved mirrors (r=-1000mm) 6 14 41 deg AoI flat mirrors, R=99% @ 1064nm (1 Damaged) 11 15

There seem to be enough parts to build 2 PMCs + spares.

I find several problems in the metal PMCs:

PMC1 has a broken screw in one of its flat mirror mounts (Attachment 16). We need to get it out in the machine shop.

PMC2 one of the flat mirrors has a scratch on the AR coating and its ORing is failing (Attachment 17). Mirror and ORing need to be replaced.

I measure the physical dimensions of the PMC with the help of https://dcc.ligo.org/LIGO-E1400332. The roundtrip is found to be 24cm which gives an FSR of 1.25GHz.

I use Evan Hall's Python script for calculating the mode spectrum as a function of the cavity length of the metal PMC and overlay the RF sidebands (Green dashed lines) on it (Attachment 18) to check for any HOM coincidence. The width of the lines is the mode splitting due to the cavity astigmatism.

It seems like the only issue might come from a 10th order modes (green ribbon) which are hopefully small enough in reality.

15201   Mon Feb 10 09:40:54 2020 Larry WallaceSummaryGeneralSolidWorks Computer Upgrade and Printer repair

On February 5, 2020, the Dell engineering workstation located in the 40M lab, was replaced with a newer Engineering workstation, per a request from Koji . The new workstation should perform a good deal better over the older unit. It has more cores, more memory and a better video card. Since this unit is being used by the 40M group, the Comsol s/w pkg. was also installed on the unit.

During the computer swap, Koji had a problem with a print job and it was discovered the bottom tray of the HP5550 printer was broken. The broken tray was replaced from another unit that was being disposed of.

15203   Mon Feb 10 15:04:42 2020 JordanUpdateGeneralHDMI Routing for new tv

Ran HDMI to the new tv mounted on the north wall of control room.

15222   Mon Feb 24 08:36:32 2020 ChubUpdateGeneralHVAC repair

The HVAC people replaced a valve and repaired the pneumatic plumbing on the roof air handler.  Temperature has been stable during the day since Thursday.  If anyone is in the control room during the evening, please make a note of the temperature.

Chub

15270   Thu Mar 12 11:10:49 2020 YehonathanUpdateGeneralPMC got unlcoked

Came this morning to find the PMC was unlocked since 6AM. Laser is still on, but PMC REFL PD DC shows dead white constant 0V on PMC screen. All the controls on the PMC screen show constant 0V actually except for the PMC_ERR_OUTPUT which is a fast channel.

I restarted the IOC but it didn't help.

I am now rebooting c1psl... That seemed to help. PMC screen seem to be working again. I am able to lock the PMC now.

IMC was locking easily once some switches on the MC servo screen were put to normal states.

TTs were grossly misaligned. Onces they where aligned, arm cavities were locking easily. Dither align for the X arm is very slow though...

15271   Thu Mar 12 12:44:34 2020 gautamUpdateGeneralPMC got unlcoked

Of course the reboot wiped any logs we could have used for clues as to what happened. Next time it'll be good to preserve this info. I suspect the local subnet went down.

P.S. for some reason the system logs are priveleged now - I ran sudo sysctl kernel.dmesg_restrict=0 on c1psl to make it readable by any user. This change won't persist on reboot.

 Quote: I restarted the IOC but it didn't help. I am now rebooting c1psl... That seemed to help. PMC screen seem to be working again. I am able to lock the PMC now.
15286   Mon Mar 30 19:02:49 2020 ranaUpdateGeneraldonated cleanroom supplies to Hospitals

Yesterday evening I took nearly all of the masks, gloves, gowns, alcohol wipes, hats, and shoe covers. These were the ones in the cleanroom cabinets at the east end of the Y-arm, as well as the many boxes under the yarm near those cabinets.

This photo album shows the stuff, plus some other random photos I took around the same time (6-7 PM) of the state of parts of the lab.

15301   Mon Apr 13 15:28:07 2020 KojiUpdateGeneralPower Event and recovery

[Larry (on site), Koji & Gautam (remote)]

Network recovery (Larry/KA)

• Asked Larry to get into the lab.

• 14:30 Larry went to the lab office area. He restarted (power cycled) the edge-switch (on the rack next to the printer). This recovered the ssh-access to nodus.

Nodus recovery (KA)

• Apr 12, 22:43 nodus was restarted.

• Apache (dokuwiki, svn, etc) recovered along with the systemctl command on wiki

• ELOG recovered by running the script

Control Machines / RT FE / Acromag server Status

• Judging by uptime, basically only the machines that are on UPS (all control room workstations + chiara) survived the power outage. All RT FEs are down. Apart from c1susaux, the acromag servers are back up (but the modbus processes have NOT been restarted yet). Vacuum machine is not visible on the network (could just be a networking issue and the local subnet to valves/pumps is connected, but no way to tell remotely).

• KA imagines that FB took some finite time to come up. However, the RT machines required FB to download the OS. That made the RTs down. If so, what we need is to power cycle them.

• Acromag: unknown state

The power was lost at Apr 12 22:39:42, according to the vacuum pressure log. The power loss was for a few min.

15303   Tue Apr 14 23:50:06 2020 KojiUpdateGeneral40m power glitch recovery

[Koji / Gautam (Remote)]

Lab status

• Gray Panel: The lab AC was off. Turned on all three (N/S, CTRL RM, E/W)
• The control room AC was running.

Work stations

• Control Room: All the control machines were running. We knew that nodus/chiara/fb were running
• 1X6/7:
• JETSTOR was making beeping sound. “Power #1 failed””power #2 failed”
• Optimus & megatron were off -> turned on -> up and running now
• 1X1/2:
• Power cycled the netgear at the top of the IOO rack (maybe not necessary)
• Turned on c1ioo -> up and running now
• 1X4/5: Rebooted c1sus / c1lsc -> up and running now
• 1X9: Rebooted c1iscex -> up and running now
• 1Y4: Rebooted c1iscex -> up and running now

Vacuum status

• Looked like everything was running as if it did not see the power glitch
• TP1 normal: Set speed 33.6k rpm / Actual speed 33.6k rpm
• TP2 normal: 66k rpm / PTP2 16.0 mtorr
• TP3 normal: 31k rpm / PTP3 45.4mtorr
• P1 LOW / P2 1.7mtorr / CC2 1.1e-6 / P3 7.6e-2 / P4 LO
• Annuli: 2.7~3torr
• CC1 9.6e-6 / SUPER BEE 0.9mtorr

C1VAC recovery

• c1vac was alive, but was isolated from the martian network
• Checked the network I/F status with /sbin/ifconfig -a
• eth1 had the vac subnet IP (192.168.114.9)
• Ran sudo /sbin/ifdown eth0 then  sudo /sbin/ifup eth0
• The I/F eth0 started running and c1vac became visible from martian
• Later checked the vacuum screen: The pressure values and valve statuses looked normal.
The interlock state was “running”. The system state was “unrecognized”.

End RTS recovery

• The end slow machines (auxex and auxey) were already running
• Restarting end RT models:
• c1iscey -> rtcds start --all
• c1iscex -> rtcds start --all
• Confirmed that the models can dump the SUSs

Vertex RTS recovery

• We wanted to use the reboot script. (/opt/rtcds/caltech/c1/scripts/cds/rebootC1LSC.sh)
• c1susaux​​
• To be safe, we wanted to bring c1susaux first.
• c1susaux does not make the network I/Fs up automatically upon reboot.
-> Connect an LCD display / keyboard / mouse to c1susaux
-> Ran sudo /sbin/ifup eth0 and sudo /sbin/ifup eth1
• Now c1susaux is visible from martian.
sudo systemctl start modbusIOC.service
-> c1susaux epics is up and running now
• ...Meanwhile c1susaux lost its eth1 somehow. This made the slow values of 8 vertex sus all zero
-> Ran sudo /sbin/ifdown eth1 and sudo /sbin/ifup eth1 again on c1susaux ->  this resolved the issue
• c1psl
sudo systemctl start modbusIOC.service
-> c1psl epics is up and running now
• Prepared for the rebooting script
• Ran /opt/rtcds/caltech/c1/scripts/cds/rebootC1LSC.sh
• Rebooting was done successfully. All the suspensions looked free and healthy.
• Burtrestored c1susaux (used Apr 12 21:19 snapshot)

Hardware

• PSL laser / Xend AUX laser / Yend AUX laser were off -> turned on
• The PMC was immediately automatically locked.
• The main marconi was off -> forgot to turn on
• The end temp controllers for the SHG crystals were on but not enabled -> now enabled

RTS recovery ~ part 2

• FB: FB status of all the RTS models were still red
• Timing: c1x01/2/3/5 were 1 sec behind of FB and c1x04 was 2 sec behind
• -> Remedy:  https://nodus.ligo.caltech.edu:8081/40m/14349
• Software rebooting of FB
• Manually start the open-mx and mx services using
• sudo systemctl start open-mx.service
• sudo systemctl start mx.service
• Check that the system time returned by gpstime matches the gpstime reported by internet sources. e.g. http://leapsecond.com/java/gpsclock.htm
• Manually start the daqd processes using
sudo systemctl start daqd_*
• This made all the FB(FE) indicators green!
• Ran the reboot script again -> All green!

IMC recovery

• The IMC status was checked
• No autolocker, but it could be manually locked. i.e. MC1/2/3 were not so much misalignment
• Autolocker/Slow FSS recovery along with https://nodus.ligo.caltech.edu:8081/40m/15121
• sudo systemctl start MCautolocker.service
• sudo systemctl start FSSSlow.service
• Both of them failed to run
• Note by Gautam: The problem with the systemctl commands failing was that the NFS mount points weren’t mounted. Which in turn was because of the familiar /etc/resolv.conf problem. I added chiara to the namespace in this file, and then manually mounted the NFS mount points. This fixed the problem.
Now the IMC is locked and the autolocker is left running.

Burt restore

• Used Apr 12 21:19 snapshot
• c1psl
• c1alsepics/c1assepics/c1asxepics/c1asyepics
• c1aux/c1auxex/c1auxey/
• c1iscaux/c1susaux
• This made REFL and AS beams back to the CCDs. As has small fringes.
• Y arm has small IR flashes as well as green flashes.

JETSTOR recovery

• JETSTOR was beeping.
• Shutdown megatron
• Followed the instruction https://nodus.ligo.caltech.edu:8081/40m/13107
• This stopped beeping. Waiting for JETSTOR to come up -> In a minute, JETSTOR display became normal and all disks showed green.
• Bring megatron back up again

N2 bottle

• The left N2 bottle was empty. The right one had 1500PSI.
• Replaced the left bottle with the spare one in the room.
• Now the left one 2680PSI and the right one 1400PSI.

Closing

• Closed PSL/AUX laser shutters
• Turned off the lights in the lab, CTRL room, and the office.

Remaining Issues

• [done] MCAutoLocker / FSSSlow scripts are not running
• The PRM alignment slider has no effect (although the PRM is aligned…) -> SLOW DAQ frozen???
• JETSTOR is not mounted on megatron [gautam mounted Jetstor on megatron on 4/18 at 2pm]
15308   Mon Apr 20 17:49:58 2020 gautamUpdateGeneralSome housekeeping
• Empty N2 replaced.
• Logged back into zita and started the StripTool traces (even though we keep the TV off nowadays).
• c1susaux acro-crate power cycled to re-enable PRM suspension control (all other vertex optics also now respond to slow bias voltage sliders being moved).
• c1iscaux needed a hard reboot as it wasn’t seen on martian. I power cycled the crate for good measure.
• Marconi turned back on with correct frequency/amplitude.
• c0rga is now seen again on martian network. I re-enabled the RGA scanning so that it takes a scan every morning at 4am.
• The forepumps for TP2/TP3 are noisier than I remember. The former has ~10,000 hrs on the clock. How often does the tip seal replacement need to happen?
• HV supplies for ASX/ASY PZTs re-energized.
• IFO re-aligned for locking.
• c1oaf and c1daf models restarted. c1oaf required the usual start/stop/start sequence to make the DAQ errors go away, and luckily the FE didn’t crash when the model was unloaded.
• POX/POY/PRMI 1f carrier/green locking all was smooth.
• For some reason, the PRC angular FF filters i trained no longer do anything good (but MCL is still good). collected 20mins of PRMI 1f locked data for investigations.
Update 21 Apr 2020 1200: Looking at Attachments #1 and #2, the spectra for motion sensed by the POP QPD does indeed look very different on Apr 6 vs Apr 20. Could be some interference from Oplev loop or maybe some EPICS values didn't get reset correctly, needs more investigation. It doesn't seem reasonable to me that the plant changes by so much (spectra were taken at similar times of the day, ~5pm).
Update 22 Apr 2020 1500: As suspected, the PRM oplev was disabled for whatever reason. Re-enabling it, I recovered the good performance from two weeks ago. ✅
15340   Wed May 20 19:34:58 2020 KojiUpdateGeneralITM spares and New PR3 mirrors transported to Downs for phasemap measurement

Two ITM spares (ITMU01/ITMU02) and five new PR3 mirrors (E1800089 Rev 7-1~Rev7-5) were transported to Downs for phasemap measurement

ELOG V3.1.3-