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ID Date Authorup Type Category Subject
  16341   Fri Sep 17 00:56:49 2021 KojiUpdateGeneralAwesome

The Incredible Melting Man!


  16342   Fri Sep 17 20:22:55 2021 KojiUpdateSUSEQ M4.3 Long beach

EQ  M4.3 @longbeach
2021-09-18 02:58:34 (UTC) / 07:58:34 (PDT)

  • All SUS Watchdogs tripped, but the SUSs looked OK except for the stuck ITMX.
  • Damped the SUSs (except ITMX)
  • IMC automatically locked
  • Turned off the damping of ITMX and shook it only with the pitch bias -> Easily unstuck -> damping recovered -> realignment of the ITMX probably necessary.
  • Done.
  16344   Mon Sep 20 14:11:40 2021 KojiUpdateBHDEnd DAC Adapter Unit D2100647

I've uploaded the schematic and PCB PDF for End DAC Adapter Unit D2100647.

Please review the design.

  • CH1-8 SUS actuation channels.
    • 5CHs out of 8CHs are going to be used, but for future extensions, all the 8CHs are going to be filled.
    • It involves diff-SE conversion / dewhitening / SE-diff conversion. Does this make sense?
  • CH9-12 PZT actuation channels. It is designed to send out 4x SE channels for compatibility. The channels have the jumpers to convert it to pass through the diff signals.
  • CH13-16 are general purpose DIFF/SE channels. CH13 is going to be used for ALS Laser Slow control. The other 3CHs are spares.

The internal assembly drawing & BOM are still coming.

  16350   Mon Sep 20 21:56:07 2021 KojiUpdateComputersWifi internet fixed

Ug, factory resets... Caltech IMSS announced that there was an intermittent network service due to maintenance between Sept 19 and 20. And there seemed some aftermath of it. Check out "Caltech IMSS"


  16376   Mon Oct 4 18:00:16 2021 KojiSummaryCDSc1teststand problems summary

I don't know anything about mx/open-mx, but you also need open-mx,don't you?

controls@c1ioo:~ 0$ systemctl status *mx*
● open-mx.service - LSB: starts Open-MX driver
   Loaded: loaded (/etc/init.d/open-mx)
   Active: active (running) since Wed 2021-09-22 11:54:39 PDT; 1 weeks 5 days ago
  Process: 470 ExecStart=/etc/init.d/open-mx start (code=exited, status=0/SUCCESS)
   CGroup: /system.slice/open-mx.service
           └─620 /opt/3.2.88-csp/open-mx-1.5.4/bin/fma -d

● mx_stream.service - Advanced LIGO RTS front end mx stream
   Loaded: loaded (/etc/systemd/system/mx_stream.service; enabled)
   Active: active (running) since Wed 2021-09-22 12:08:00 PDT; 1 weeks 5 days ago
 Main PID: 5785 (mx_stream)
   CGroup: /system.slice/mx_stream.service
           └─5785 /usr/bin/mx_stream -e 0 -r 0 -w 0 -W 0 -s c1x03 c1ioo c1als c1omc -d fb1:0


  16378   Mon Oct 4 20:46:08 2021 KojiUpdateElectronicsSatellite amp box adapters

Thanks. You should be able to find the chassis-related hardware on the left side of the benchtop drawers at the middle workbench.

Hardware: The special low profile 4-40 standoff screw / 1U handles / screws and washers for the chassis / flat-top screws for chassis panels and lids

  16380   Tue Oct 5 17:01:20 2021 KojiUpdateElectronicsSat Amp modifications

Make sure the inputs for the PD amps are open. This is the current amplifier and we want to leave the input pins open for the test of this circuit.

TP6 is the first stage of the amps (TIA). So this stage has the issue. Usual check if the power is properly supplied / if the pins are properly connected/isolated / If the opamp is alive or not.

For TP8, if TP8 get railed. TP5 and TP7 are going to be railed too. Is that the case, if so, check this whitening stage in the same way as above.
If the problem is only in the TP5 and/or TP7 it is the differential driver issue. Check the final stage as above. Replacing the opamp could help.


  16387   Thu Oct 7 02:04:19 2021 KojiUpdateElectronicsSatellite amp adapter chassis

The 4 units of Satellite Amp Adapter were done:
- The ears were fixed with the screws
- The handles were attached (The stock of the handles is low)
- The boards are now supported by plastic stand-offs. (The chassis were drilled)
- The front and rear panels were fixed to the chassis
- The front and rear connectors were fixed with the low profile 4-40 stand-off screws (3M 3341-1S)

  16397   Tue Oct 12 23:42:56 2021 KojiSummaryCDSConnected c1sus2 to martian network

Don't you need to add the new hosts to /diskless/root/etc/rtsystab at fb1? --> There looks many elogs talking about editing "rtsystab".

controls@fb1:/diskless/root/etc 0$ cat rtsystab
# host    list of control systems to run, starting with IOP
c1iscex  c1x01  c1scx c1asx
c1sus     c1x02  c1sus c1mcs c1rfm c1pem
c1ioo     c1x03  c1ioo c1als c1omc
c1lsc    c1x04  c1lsc c1ass c1oaf c1cal c1dnn c1daf
c1iscey  c1x05 c1scy c1asy
#c1test   c1x10  c1tst2


  16404   Thu Oct 14 18:30:23 2021 KojiSummaryVACFlange/Cable Stand Configuration

Flange Configuration for BHD

We will need total 5 new cable stands. So Qty.6 is the number to be ordered.

Looking at the accuglass drawing, the in-vaccum cables are standard dsub 25pin cables only with two standard fixing threads.


For SOSs, the standard 40m style cable bracket works fine. https://dcc.ligo.org/D010194-x0

However, for the OMCs, we need to make the thread holes available so that we can mate DB25 male cables to these cables.
One possibility is to improvise this cable bracket to suspend the cables using clean Cu wires or something. I think we can deal with this issue in situ.

Ha! The male side has the 4-40 standoff (jack) screws. So we can hold the male side on the bracket using the standoff (jack) screws and plug the female cables. OK! The issue solved!


  16408   Fri Oct 15 17:17:51 2021 KojiSummaryGeneralVent Prep

I took over the vent prep: I'm going through the list in [ELOG 15649] and [ELOG 15651]. I will also look at [ELOG 15652] at the day of venting.

  1. IFO alignment: Two arms are already locking. The dark port beam is well overlapped. We will move PRM/SRM etc. So we don't need to worry about them. [Attachment 1]
    scripts>z read C1:SUS-BS_PIT_BIAS C1:SUS-BS_YAW_BIAS
    scripts>z read C1:SUS-ITMX_PIT_BIAS C1:SUS-ITMX_YAW_BIAS
    scripts>z read C1:SUS-ITMY_PIT_BIAS C1:SUS-ITMY_YAW_BIAS
    scripts>z read C1:SUS-ETMX_PIT_BIAS C1:SUS-ETMX_YAW_BIAS
    scripts>z read C1:SUS-ETMY_PIT_BIAS C1:SUS-ETMY_YAW_BIAS

  2. IMC alignment: Locking nicely. I ran WFS relief to move the WFS output on to the alignment sliders. All the WFS feedback values are now <10. Here is the slider snapshots. [Attachment 2]
  3. PMC alignmnet: The PMC looked like it was quite misaligned -> aligned. IMC/PMC locking snapshot [Attachment 3]
    Arm transmissions:
    scripts>z avg 10  C1:LSC-TRX_OUT C1:LSC-TRY_OUT
    C1:LSC-TRX_OUT 0.9825591325759888
    C1:LSC-TRY_OUT 0.9488834202289581

  4. Suspension Status Snapshot [Attachment 4]
  5. Anchal aligned the OPLEV beams [ELOG 16407]
    I also checked the 100 days trend of the OPLEV sum power. The trend of the max values look flat and fine. [Attachment 5] For this purpose, the PRM and SRM was aligned and the SRM oplev was also aligned. The SRM sum was 23580 when aligned and it was just fine (this is not so visible in the trend plot).
  6. The X and Y green beams were aligned for the cavity TEM00s. Y end green PZT values were nulled. The transmission I could reach was as follows.

    It seems that these GTRX and GTRY seemed to have crosstalk. When each green shutters were closed the transmissino and the dark offset were measured to be

    Note that Y green seemed to have significant (~0.1) of 1st order HOM. I don't know why I could not transfer this power into TEM00. I could not find any significant clipping of the TR beams on the PSL table PDs.
  7. IMC Power reduction
    Now we have nice motorized HWP. sitemap -> PSL -> Power control
    == Initial condition == [Attachment 6]
    C1:IOO-HWP_POS 38.83
    Measured input power = 0.99W
    C1:IOO-MC_RFPD_DCMON = 5.38
    == Power reduction == [Attachment 7]
    - The motor was enabled upon rotation on the screen

    C1:IOO-HWP_POS 74.23
    Measured input power = 98mW
    C1:IOO-MC_RFPD_DCMON = 0.537
    - Then, the motor was disabled
  8. Went to the detection table and swapped the 10% reflector with the 98% reflector stored on the same table. [Attachments 8/9]
    After the beam alignment the MC REFL PD received about the same amount of the light as before.
    C1:IOO-MC_RFPD_DCMON = 5.6
    There is no beam delivered to the WFS paths.
  9. The IMC can already be locked with this configuration. But for the MC Autolocker, the MCTRANS threshold for the autolocker needs to be reduced as well.
    This was done by swapping a line in  /opt/rtcds/caltech/c1/scripts/MC/AutoLockMC.init
    # BEFORE
    /bin/csh ./AutoLockMC.csh >> $LOGFILE
    #/bin/csh ./AutoLockMC_LowPower.csh >> $LOGFILE
    # AFTER
    #/bin/csh ./AutoLockMC.csh >> $LOGFILE
    /bin/csh ./AutoLockMC_LowPower.csh >> $LOGFILE

    Confirmed that the autolocker works a few times by toggling the PSL shutter. The PSL shutter was closed upon the completion of the test
  10. Walked around the lab and checked all the bellows - the jam nuts are all tight, and I couldn't move them with my hands. So this is okay according to the ancient tale by Steve.
  16409   Fri Oct 15 20:53:49 2021 KojiSummaryGeneralVent Prep

From the IFO point of view, all look good and we are ready for venting from Mon Oct 18 9AM

  16410   Mon Oct 18 10:02:17 2021 KojiUpdateVACVent Started / Completed

[Chub, Jordan, Anchal, Koji]

- Checked the main volume is isolated.
- TP1 and TP2 were made isolated from other volumes. Stopped TP1. Closed V4 to isolate TP1 from TP2.
- TP3 was made isolated. TP3 was stopped.
- We wanted to vent annuli, but it was not allowed as VA6 was open. We closed VA6 and vented the annuli with VAVEE.
- We wanted to vent the volume between VA6, V5, VM3, V7 together with TP1. So V7 was opened. This did not change the TP1 pressure (P2 = 1.7mmTorr) .
- We wanted to connect the TP1 volume with the main volume. But this was not allowed as TP1 was not rotating. We will vent TP1 through TP2 once the vent of the main volume is done.

- Satrted venting the main volume@Oct 18, 2021 9:45AM PDT

- We started from 10mTorr/min, and increased the vent speed to 200mTorr/min, 700mTorr/min, and now it is 1Torr/min @ 20Torr
- 280Torr @11:50AM
- 1atm  @~2PM

We wanted to vent TP1. We rerun the TP2 and tried to slowly introduce the air via TP2. But the interlock prevents the action.

Right now the magenta volume in the attachment is still ~1mTorr. Do we want to open the gate valves manually? Or stop the interlock process so that we can bypass it?

  16412   Tue Oct 19 10:59:09 2021 KojiUpdateVACVent Started / Completed

[Chub, Jordan, Yehonathan, Anchal, Koji]

North door of the BS chamber opened


  16413   Tue Oct 19 11:30:39 2021 KojiUpdateVACHow to vent TP1

I learned that TP1 was vented through the RGA room in the past. This can be done by opening VM2 and a manual valve ("needle valve")
I checked the setup and realized that this will vent RGA. But it is OK as long as we turns of the RGA during vent and bake it once TP1 is back.

Additional note:

- It'd be nice to take a scan for the current background level before the work.
- Turn RGA EM and filament off, let it cool down overnight. 
- Vent with clean N2 or clean air. (Normal operating temp ~80C is to minimize accumulation of H-C contaminations.)
- There is a manual switch and indicators on the top of the RGA amp. It has auto protection to turn filament off if the pressure increase over ~1e-5.

  16415   Tue Oct 19 23:43:09 2021 KojiSummaryCDSc1sus2 DAC to ADC test

(Because of a totally unrelated reason) I was checking the electronics units for the upgrade. And I realized that the electronics units at the test stand have not been properly powered.

I found that the AA/AI stack at the test stand (Attachment 1) has an unusual powering configuration (Attachment 2).
- Only the positive power supply was used / - The supply voltage is only +15V / - The GND reference is not connected to anywhere.

For confirmation, I checked the voltage across the DC power strip (Attachments 3/4). The positive was +5.3V and the negative was -9.4V. This is subject to change depending on the earth potential.

This is not a good condition at all. The asymmetric powering of the circuit may cause damages to the opamps. So I turned off the switches of the units.

The power configuration should be immediately corrected.

  1. Use both positive and negative supply (2 power supply channels) to produce the positive and the negative voltage potentials. Connect the reference potential to the earth post of the power supply.
    https://www.youtube.com/watch?v=9_6ecyf6K40   [Dual Power Supply Connection / Serial plus minus electronics laboratory PS with center tap]
  2. These units have DC power regulator which produces +/-15V out of +/-18V. So the DC power supplies are supposed to be set at +18V.


  16418   Wed Oct 20 15:58:27 2021 KojiUpdateVACHow to vent TP1

Probably the hard disk of c0rga is dead. I'll follow up in this elog later today.

Looking at the log in /opt/rtcds/caltech/c1/scripts/RGA/logs , it seemed that the last RGA scan was Sept 2, 2021, the day when we had the disk full issue of chiara.
I could not login to c0rga from control machines.
I was not aware of the presence for c0rga until today, but I could locate it in the X arm.
The machine was not responding and it was rebooted, but could not restart. It made some knocking sound. I am afraid that the HDD failed.

I think we can
- prepare a replacement linux machine for the python scripts
- integrate it with c1vac

  16428   Tue Oct 26 14:53:24 2021 KojiUpdateElectronicsRack

1. We have a rack at the 40m storage. We are free to take it to the lab. If there is a tag, tell the info to Liz. Let's move it to the lab tomorrow right after the meeting.

2. We have a few racks in WB B1 (Attachment 1). Liz and I checked a rack which looks suitable for us. 46U height. Caltech transport will move it to the lab.

  16434   Wed Oct 27 18:11:37 2021 KojiSummaryBHDPart II of BHR upgrade - Relocation of TT2 and MMT1/2 alignment

Closed the PSL shutter @18:11
During the vent, we want to keep the cavity unlocked if not necessary.


  16435   Wed Oct 27 18:16:45 2021 KojiSummaryBHDPart II of BHR upgrade - Relocation of TT2 and MMT1/2 alignment

- Moving the MMT2 south by a cm is fine. This will give you ~0.5cm at TT1 without changing the other alignment much.
- IMC mode is moving because of your presence + HEPA blow.
- 2cm at Faraday is plenty for the beam diameter of a few mm.


  16436   Wed Oct 27 19:34:52 2021 KojiSummaryElectronicsNew electronics racks

1. The rack we cleaned today (came from West Bridge) will be placed between 1X3 and 1X4, right next to 1X4 (after removing the plastic boxes). (Attachment 1)
For easier work at the side of the 1X4, the side panel of the 1X4 should be removed before placing the new rack. Note that this rack is imperial and has 10-32 threads

2. In terms of the other rack for the Y arm, we found the rack in the storage is quite dirty. Anchal pointed out that we have a few racks standing along the Y arm (as the storage of the old VME/Euro card electronics) (Attachments 2/3)
They are not too dirty and also doing nothing there. Let's vacate one of them (the one right next to the optics preparation table). Use this space as a new storage area placing a wire shelving rack for something.

BTW, I thought it is good to have the rack at the vertex side of 1Y1 (as 1Y0?), but the floor has "KEEP OUT" marking. I have no idea why we have this marking. Is this for crane operation??? Does any one know?

  16442   Mon Nov 1 14:51:34 2021 KojiUpdateGeneralChecking the vent plan

The vent team described a detailed vent plan (and reports where the actions have been performed)


- [Sec.4] We should decide the final PR2 mirror through table-top measurements.

- [Sec 6] BS alignment is probably "unknown" now. So it'd be better to use the ITMY spot as the reference, then align BS for ITMX. For temporary alignment, it's OK though.

- [Sec 9-11] RIght now there is no mounts to place LO3/LO4/AS2/AS3/BHDBS. But we probably want to test something before the installation of the BHD? Just place the BHDBS on a optics mount so that we get an interfered beam on ITMY?

At this point we are supposed to have all the electronics all the CDS necessary for the new SOS control. Otherwise, they are just swinging and the alignment work will just be impossible.

- [Sec 15] The OPLEV mirrors can be freely moved as long as it does not block the main IR beams. Moving ITMXOL1 makes the reflection blocked by ITMXOL2. And moving ITMXOL2 would make the IR beams clipped. Consider replacing the mounts with a fixed mount. (The OPLEV mirrors are 1.5" in dia. It is not common vacuum compatible 1.5inch mounts. If 1" Al mirror is sufficient, we can use it.


- The arms are the most strict alignment requirement. Everything else will follow the arm alignment. So start from the arms and propagate the alignment to Michelson / PRMI / SRMI.

- We reestablish arm alignment using the end green beams.

- Then recover IR arm alignment. Consider using ASS if possible

  16446   Tue Nov 2 22:50:30 2021 KojiUpdateBHDSOS assembly

2.5Hz is surprising. Can you move it down to sub 1Hz by adding a socket cap screw at the top instead of the set screw for the Teflon piece? How much mass do you need to add?

  16448   Thu Nov 4 15:03:43 2021 KojiSummaryBHD1Y1 rack work

I have visited the binder file for the 40m wiring file in the control room.
The 12V power supply on 1Y1 is for the CCD cameras. So we still want to keep the 12V 0.8A power and the side connections for these. It is not necessary to be Sorensen. Can we replace it with an AC-DC adapter with +12V/1A for example? BTW, the video matrix and quads are AC-powered.

The mysterious thick cables and cross-connects (green wires) on the side panel (labeled AP1/AP2/SP/IMCREFL) are for "EO shutters". It was meant for the protection of the PDs from bright beams.
I don't think they have been used. And we don't need them.

  16452   Fri Nov 5 20:35:10 2021 KojiUpdateBHDFeedthru / Optical Mounts

- New feedthrus [4xDB25 Qty 4 / 8xDB25 Qty 1] are placed on the wire shelf at the entrance -> Jordan, please clean them.

- There are plenty of 2" DLC mounts. There are also many 1.5" mounts but they are less useful.
  We need at least 3 1" moounts and 1 1" or 2" lens mount (and the lens). Let's purchase them on Thorlabs. I'll work on the order.

  16454   Mon Nov 8 13:13:00 2021 KojiSummaryBHD1Y1 rack work; Sorensens removed

Updated the rack layout. Now there is an issue.
We were supposed to have 1U space at the top, but it was occupied by the 12V.
We need to either lower the c1sus2 and IO chassis 1U or move the Sorensen at the bottom.

  16458   Mon Nov 8 18:42:38 2021 KojiSummaryBHDRack Layout / Power Strips
Rack # of units that
requires +18V
Power Source
1X3 (new rack) 15 1X3 U1/2
1X4 13 1X3 U1/2
1X5 8 or 9 (OL AA) 1X5 U40/41
1Y0 17 1Y0 U1/2
1Y1 15 1Y0 U1/2
1Y3 12 1Y3 U39/40
1X9 9 1X9 U38/39
1Y4 9

1Y4 U39/40


  • There are 8 racks and there is only 7x 18V power strips. 1X5 could be the one without the power strip and to parasite with 1X3/4. Otherwise we need to modify some of the 24V power strips (no plan to use) into 18V by replacing the connectors.
  • We need total ~100 18V cables / We ordered 60x 3ft / 60x 3ft / 30x 10ft. Hopefully these are enough for our depand... I haven't checked the delivered number.
  • All the acromags are supposed to be powered with one voltage. I think they are supposed to run with +18V.
  • I didn't check the distribution of Sorensens through the lab. (i.e. how many we have / how many we need / ...)
  16464   Thu Nov 11 00:11:39 2021 KojiSummarySUS2" to 3" sleeve issue

Yehonathan and Tega found that the new PR3 and SR3 delivered in 2020 is in fact 3/4" in thickness (!). Digging the past email threads, it seems that the spec was 10mm but the thickness was increased for better relieving the residual stress by the coatings.

There are a few issues.

1. Simply the mirror is too thick for the ring. It sticks out from the hole. And the mirror retainers (four plastic plates) are too far from the designed surface, which will make the plates tilted.

2. The front side of the mirror assembly is too heavy and the pitch adjustment is not possible with the balance mass.

Some possible solutions:

- How about making the recess deeper?
In principle this is possible, but the machining is tricky because the recess is not a simple round hole but has "pads" where the mirror sits. And the distance of the retainer to the thread is still far.
And the lead time might become long.

- How about making new holes on the ring to shift the clamp?
Yes it is possible. This will shift the mirror assembly by a few mm. Let's consider this.

- How about modifying the wire blocks?
Yes it is equivalent to shift the holes on the ring. Let's consider this too.

1. How to hold the mirror with the retainer plates

[Attachment 1] The expected distance between the retainer plate and the threaded hole is 13.4mm. We can insert a #4-40 x L0.5" stand off (McMaster-Carr 91197A150, SUS316) there. This will make the gap down to 0.7mm. With a washer, we can handle this gap with the plate. Note that we need to use vented & silver plated #4-40 screws to hold the plates.

[Attachment 2] How does this look like when the CoM is aligned with the wire plane? Oh, no... the lower two plates will interfere with the EQ stops and the EQ stop holders. We have to remove them. [Attachment 3]
We need to check with the suspension if the EQ stop screws may hit the protruded optics and can cause chipping/cracking.

2. Modifying the wire block

[Attachment 4] The 4x thru holes of the wire block were extended to be +/-0.1" slots. The slots are too long to form ovals and produce thin areas. With the nominal position of the balance mass, the clamp coordinates are y=1.016 (vertical) and z=-2.54mm (longitudinal).
==> The CoM is 0.19mm backside (magnet side) and 0.9134 mm lower from the wire clamping points. This looks mathematically doable, but the feasibility of the manufacturing is questionable.

[Attachment 5] Because the 0.1" shift of the CoM is large, we are able to make new #2-56 thread holes right next to the original ones. The clamp coordinates are y=1.016 (vertical) and z=-2.54mm (longitudinal).
==> The CoM is 0.188mm backside (magnet side) and 0.9136 mm lower from the wire clamping points. With the given parameters, the expected pitch resonant frequency is 0.756Hz

My Recommendation

- Modify the metal ring to shift the #2-56 threads by 0.1"

- The upper two retainer plates will have #4-40 x 0.5" stand off. Use vented Ag-coated #4-40 screws.

- The lower two are to be removed.

- Take care of the EQ stops.

- Of course, the best solution is to redesign the holder for 3/4" optics. Can we ask Protolab for rapid manufacturing???

Why did we need to place the mass forward to align the 1/4" thick optic?

We were supposed to adjust the CoM not to have too much adjustment. But we had to move the balance mass way too front for the proper alignment with a 1/4" thick optic. Why...?
This is because the ring was designed for a 3/8" thick optic... It does not make sense because the depth of the thread holes for the retainer plate was designed for 1/4" optics...

When the balance mass is located at the neutral position, the CoM coordinate is

x 0.0351mm (x+: left side at the front view)
y 0.0254mm (y+: vertical up)
z 0.4493mm (z+: towards back)

So, the CoM is way too behind. When the balance mass was stacked and the moved forward (center of the axis was moved forward by 0.27"), the CoM coordinate is (Attachment 6)

x 0.0351mm
y 0.0254mm
z 0.0011mm

This makes sens why we had to move the balance mass a lot for the adjustment.

  16471   Tue Nov 16 18:28:53 2021 KojiUpdateBHDSOS assembly

Yehonathan told me that the wires are touching between the clamps! I went back to the CAD and confirmed it is really happening. Sad.

The distance of the wires at the upper clamp is 17.018mm.
The distance of the lower clamps is 74.168mm
The vertical drop of the wire is 251mm
--> The wire angle from the vertical line is 0.114 rad

The lower wire block has a step of 1.016mm with the vertical extension of the piece by 11.684mm
--> The angle clearance of the lower clamp is 0.087 rad

So the clearance was not enough.

If we cut the top center of the wire block more than 2.77mm, we can make the wires free.
For safety, we can cut 0.25" = 6.35mm. This will give 0.4mm clearance between the block and the wire at the closest point.

I did this modification on the 3D model and modified the 2D drawing too, so that we can find the machine shop to do it quickly.

  16473   Wed Nov 17 11:53:27 2021 KojiUpdateGeneralwire clamp plate mod

Of course, we remove the magnet-dumbbell for machining. After that the part will be cleaned/baked again. And Yehonathan is going to glue the magnet-dumbbell again.

  16475   Thu Nov 18 14:29:01 2021 KojiSummaryBHDBHD invac optics / opto-mechanics

I went through the optics list (in the BHD procurement google spreadsheet) and summarized how to build them.

The red ones are what we need to purchase. Because of the strange height of the LMR mounts, the post needs to have none half-integer inch heights.

They need to be designed as the usual SS posts are not designed to be vac compatible (not because of the material but the design like screw hole venting).

We also need to check how many clean forks we have.
-> The components were ordered except for the custom posts.

ssome partssss
Name Optic Mount Mount OH Post Post OH Fork / Base Base OH Total Height Notes
POP_SM5  Previous POYM1 / 2" Y1-2037-0 LMR2V Thorlabs 1.36 Custom Post 4.14 SS Fork 0 5.5  
POP_SM4 New CM254-750-E03 Thorlabs LMR1V Thorlabs 0.87 Newport 9953+PLS-T238 3.88 BA1V / BA2V 0.75 5.5  
BSOL1 New 2" VIS BB2-E02 LMR2V Thorlabs 1.36 Custom Post 4.14 SS Fork 0 5.5  
ITMYOL1 New 2" VIS BB2-E02 LMR2V Thorlabs 1.36 Custom Post 4.14 SS Fork 0 5.5  
ITMYOL2 New 2" VIS BB2-E02 LMR2V Thorlabs 1.36 Custom Post 4.14 SS Fork 0 5.5  
SRMOL1 New 2" VIS BB2-E02 LMR2V Thorlabs 1.36 Custom Post 4.14 SS Fork 0 5.5  
ASL LA1779-C Thorlabs or KPX217AR.33 Newport LMR2V Thorlabs 1.36 Custom Post 4.14 SS Fork 0 5.5  
GRY_SM1 Y2-2037-0 (in hand) DLC   DLC Post   DLC Fork   5.5  
BHDBS CVI (In hand) DLC 2 DLC Post   DLC Fork   5.5 (3" post for BHD)
LO3 Lambda (in hand) POLARIS-K1-2AH Thorlabs 1 Custom Post 4.5 SS Fork 0 5.5 (3" post for BHD)
LO4 Lambda (in hand) POLARIS-K1-2AH Thorlabs 1 Custom Post 4.5 SS Fork 0 5.5 (3" post for BHD)
AS3 Lambda (in hand) POLARIS-K1-2AH Thorlabs 1 Custom Post 4.5 SS Fork 0 5.5 (3" post for BHD)
OMC1R3 Y1-1025-45P (in hand) POLARIS-K1-2AH Thorlabs 1 Custom Post 4.5 SS Fork 0 5.5 (3" post for BHD)
OMC1R4 Y1-1025-45P (in hand) POLARIS-K1-2AH Thorlabs 1 Custom Post 4.5 SS Fork 0 5.5 (3" post for BHD)
OMC2R3 Y1-1025-45P (in hand) POLARIS-K1-2AH Thorlabs 1 Custom Post 4.5 SS Fork 0 5.5 (3" post for BHD)
OMC2R4 Y1-1025-45P (in hand) POLARIS-K1-2AH Thorlabs 1 Custom Post 4.5 SS Fork 0 5.5 (3" post for BHD)
OMC1R1 Y1-1025-45P (in hand) LMR1V Thorlabs 0.87 Custom Post 4.63 SS Fork 0 5.5 (3.13" post for BHD)
OMC2R1 NB1-K14 Thorlabs LMR1V Thorlabs 0.87 Custom Post 4.63 SS Fork 0 5.5 (3.13" post for BHD)


  16490   Mon Dec 6 14:26:52 2021 KojiUpdateVACPumping down the RGA section

Jordan reported that the RGA section needs to be pumped down to allow the analyzer to run at sufficiently low pressure (P<1e-4 torr).
The RGA section was pumped down with the TP2/TP3. The procedure is as listed below.
If the pressure go up to P>1e-4 torr, we need to keep the pump running until the scan is ready.

### Monitor / Control screen setup ###
1. On c1vac: cd /cvs/cds/caltech/target/c1vac/medm
2. medm -x C0VAC_MONITOR.adl&
3. RGA section (P4) 3.6e-1 torr / P3/P2 still atm.
4. medm -x C0VAC_CONTROL.adl

### TP2/TP3 backing ###
5. Turn on AUX RP with the circuit breaker hanging on the AC.
6. Open manual valve for TP2/3/ backing / PTP2/3 ~ 8torr

### TP2/TP3 starting ###
7. Turned on TP2/TP3 with the Standby OFF

### Pump down the pump spool ###
8. Connect manual RP line (Quick Connect)
9. Turned on RP1/RP3 -> quickly reached 0.4 torr
10. Open V6 for pump spool pumping -> Immediately go down to sufficiently low pressure for TP2/TP3.
(10.5 I had to close V6 at this point)
11. Open V5 to start pumping pump spool with TP3 (TP2 still stand by) -> P3 immediately goes down below 1e-4 torr. This automatically closed V6 because of the low pressure of P3 (interlocking)

### Pump down the RGA section ###
12. Open VM3 to pump down RGA section -> P4 goes down to <1e-4 torr
13. P2 is still 2e-3. So decided to open V4 to use TP2 (now it's ready) too. -> Saturated at 1.7e-3

### Shutting down ###
14. Close VM3
15. Close V4/V5 to isolate TP2/TP3
16. Stop TP2/TP3 -> Slowing down
17. Stop RP1/RP3
18. Close the manual valves for TP2/3/ backing
19. Stop AUX RP with the circuit breaker hanging on the AC.

  16493   Tue Dec 7 13:12:50 2021 KojiUpdateVACPumping down the RGA section

So that Jordan can run the RGA scan this afternoon, I ran TP3 and started pumping down the RGA section.

- Same 1~4
- Same 5
- 6 Opened only the backing path for TP3
- 7 Turned on TP3 only

- TP3 reached the nominal full speed @75kRPM

- 11 Opened V5 to pump the pump spool -> Immediately reached P3<1e-4
- 12 Opened VM3 to pump the RGA section -> Immediately reached P4<1e-4

The pumps are kept running. I'll come back later to shut down the pumps.
=> Jordan wants to heat the filament (?) and to run the scan tomorrow.
So we decided to keep TP3 running overnight. I switched TP3 to the stand-by mode (= lower rotation speed @50kRPM)


  16501   Fri Dec 10 19:22:01 2021 KojiUpdateVACPumping down the RGA section

The scan result was ~x10 higher than the previously reported scan on 2020/9/15 (https://nodus.ligo.caltech.edu:8081/40m/15570), which was sort of high from the reference taken on 2018/7/18.

This just could mean that the vacuum level at the RGA was x10 high.
We'll just go ahead with the vacuum repair and come back to the RGA once we return to "vacuum normal".

Meanwhile, I asked Jordan to turn off the RGA to make it cool down. I shut off RGA section and turned TP2 off.

  16502   Fri Dec 10 21:35:15 2021 KojiSummarySUSVertex SUS DAC adapter ready

4 units of Vertex SUS DAC adapter (https://dcc.ligo.org/LIGO-D2100035) ready.





The units are completely passive right now and has option to extend to have a dewhitening board added inside.
So the power switch does nothing.

Some of the components for the dewhitening enhancement are attached inside the units.



  16510   Wed Dec 15 17:44:18 2021 KojiSummaryBHDPart VIII of BHR upgrade - Placed LO1

If ITMX already has another side magnet, we can migrate the side OSEM of ITMX to the other side. This way, the interference of the OSEMs can be avoided.

  16515   Thu Dec 16 15:54:08 2021 KojiUpdateElectronicsITMX feedthroughs and in-vac cables installed

Thanks for the installation.

With regard to the connector convention, let's use the attached arrangement so that it will be consistent with the existing flange DSUB configuration. Not a big deal.


  16516   Thu Dec 16 17:41:12 2021 KojiUpdateBHDCoil driver test failed for S2100619-v1

Good catch. It turned out that the both + and - side of the output stages for CH2 were oscillating at ~600kHz. If I use a capacitance sticks to touch arbitrarily around the components, it stops their oscillation and they stay calm.
It means that the phase margin becomes small while the circuit starts up.

I decided to increase the capacitances C6 and C20 (WIMA 150pF) to 330pF (WIMA FPK2 100V) and the oscillation was tamed. 220pF didn't stop them. After visually checked the signal behavior with an oscilloscope, the unit was passed to Anchal for the TF test.

The modification was also recorded in the DCC S2100619

  16519   Fri Dec 17 12:32:35 2021 KojiUpdateSUSRemaining task for 2021

Anything else? Feel free to edit this entry.

- SUS: AS1 hanging

- SUS: PR3/SR2/LO2 3/4" thick optic hanging

v Electronics chain check (From DAC to the end of the in-air cable / From the end of the in-air cable to the ADC)
[ELOG 16522]

- Long cable installation (4x 70ft)

- In-air cable connection to the flange

- In-vac wiring (connecting LO1 OSEMs)

- LO1 OSEM insertion/alignment

- LO1 Damping test


  16521   Fri Dec 17 19:16:45 2021 KojiUpdateBHDSOS assembly

We @40m do the convention of the arrow at the thinnest side & pointing the HR side, but nobody says Lambda does the same.

We can just remount the mirror without breaking the wires and adjust the pitching if you do it carefully.

Does this mean that the LO1 also likely to have the wedge pointing up? Or did you rotate the mirror to have the wedge reflection to be as horizontal as possible?

  16522   Fri Dec 17 19:19:42 2021 KojiUpdateSUSRemaining task for 2021

I had the fear that any mistake in the electronics chain could have been the show stopper.

So I quickly checked the signal assignments for the ADC and DAC chains.

I had initial confusion (see below), but it was confirmed that the electronics chains (at least for LO1) are correct.

Note: One 70ft cable is left around the 1Y0 rack


There are a few points to be fixed:

- It looks like the ADC/DAC card # assignment has been messed up.

CDS ADC0 -> Cable label ADC1 -> AA A1 -> ...
CDS ADC1 -> Cable label ADC0 -> AA A0 -> ...
CDS DAC0 -> Cable label DAC2 -> AI D2 -> ...
CDS DAC1 -> Cable label DAC0 -> AI D0 -> ...
CDS DAC2 -> Cable label DAC1 -> AI D1 -> ...
(What is going on here... please confirm and correct as they become straight forward)

Once this puzzle was solved I could confirm reasonable connections from the end of the 70 cables to the ADC/DAC.

- We also want to change the ADC card assignment. The face OSEM readings must be assigned to ADC1 and the side OSEM readings to ADC0.
  My system wiring diagram needs to be fixed accordingly too.
  This is because the last channel of the first ADC (ADC0) is not available for us and is used for DuoTone.

  16524   Sat Dec 18 00:56:14 2021 KojiUpdateBHDSOS assembly

Sad... We just need to check the wedge direction everytime, unfortunately.

Pencil: can you try to gently wipe it off with solvent & a swab? (IPA / Acetone)
If it does not come off in the end, it's all right to leave. Do we want to scribe the arrow mark? You need a diamond pen.

  16526   Mon Dec 20 13:52:01 2021 KojiUpdateBHDSOS assembly

LO1: No need to remove the pencil mark for the damping test. Until we see serious contamination on the LO1 optic, we don't need to take the optic off from the mount and clean it. If there is a chance of rehanging (because of a broken wire/etc), we do wipe the pencil mark.

Other optics: wipe the pencil mark as much as possible.

  16529   Tue Dec 21 16:35:39 2021 KojiUpdateVACITMX NW feedthru (LO1-1) connector pin bent

I've received a report that a pin of an ITMX NW feedthru connector was bent. (Attachment 1)
The connector is #1 (upper left) and planned to be used for LO1-1.

This is Pin25 and used for the PD K of OSEM #1. This means that Coil Driver #1 (3 OSEMs) uses this pin, but Coil Driver #2 (2 OSEMs) does not.

Anyways, I tried to fix it by bending it back. WIth some tools, it was straightened enough for plugging the cable connector. (Attachment 2)

It seemed that the pins were exceptionally soft compared to the ones used for usual DSUBs, probably because of the vacuum compatibility.
So it's better to approach the pins in parallel to the surface and not apply mating pressure until you are sure that all the 25pins are inserted in the counterpart holes.

  16532   Wed Dec 22 14:57:05 2021 KojiUpdateGeneralchiara local backup

chiara local backup of /cvs/cds has not been running since the move of chiara in Nov 19. The remote backup has not been taken since 2017.
The lack of the local backup was because of the misconfiguration of /etc/fstab.

It was fixed and now the backup disk was mounted. We'll see the backup script running tomorrow morning.
The backup disk is smaller than the main disk. So sooner or later, we will face the backup problem again.

localbackup script was crying because there was no backup disk.

backup>tail localbackup.log
2021-12-18 07:00:02,002 INFO       Updating backup image of /cvs/cds
2021-12-18 07:00:02,002 ERROR      External drive not mounted!!!
2021-12-19 07:00:01,146 INFO       Updating backup image of /cvs/cds
2021-12-19 07:00:01,146 ERROR      External drive not mounted!!!
2021-12-20 07:00:01,255 INFO       Updating backup image of /cvs/cds
2021-12-20 07:00:01,255 ERROR      External drive not mounted!!!
2021-12-21 07:00:01,361 INFO       Updating backup image of /cvs/cds
2021-12-21 07:00:01,361 ERROR      External drive not mounted!!!
2021-12-22 07:00:01,469 INFO       Updating backup image of /cvs/cds
2021-12-22 07:00:01,470 ERROR      External drive not mounted!!!

fstab had no entry for the backup disk.

backup>cat /etc/fstab
# /etc/fstab: static file system information.
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    nodev,noexec,nosuid 0       0
# / was on /dev/sda1 during installation
UUID=972db769-4020-4b74-b943-9b868c26043a /               ext4    errors=remount-ro 0       1
# swap was on /dev/sda5 during installation
UUID=a3f5d977-72d7-47c9-a059-38633d16413e none            swap    sw              0       0

#UUID="90a5c98a-22fb-4685-9c17-77ed07a5e000"    /media/40mBackup       ext4      defaults,relatime,commit=60       0         0

# CURRENT BACKUP DISK as of 2021/09/02
#UUID="1843f813-872b-44ff-9a4e-38b77976e8dc"    /media/40mBackup       ext4      defaults,relatime,commit=60       0         0

#fb:/frames      /frames nfs     ro,bg

# CURRENT MAIN DISK as of 2021/09/02
# UUID=92dc7073-bf4d-4c58-8052-63129ff5755b   /home/cds    ext4    defaults,relatime,commit=60    0   0
UUID="1843f813-872b-44ff-9a4e-38b77976e8dc"   /home/cds    ext4   defaults,relatime,commit=60    0   0

Checked the dev name of the disks and the UUIDs

backup>sudo lsblk
[sudo] password for controls:
sda      8:0    0 465.8G  0 disk
├─sda1   8:1    0 446.9G  0 part /
├─sda2   8:2    0     1K  0 part
└─sda5   8:5    0  18.9G  0 part [SWAP]
sdb      8:16   0   5.5T  0 disk
└─sdb1   8:17   0   5.5T  0 part /home/cds
sdc      8:32   0   3.7T  0 disk
└─sdc1   8:33   0   3.7T  0 part
sr0     11:0    1  1024M  0 rom
backup> sudo blkid
/dev/sda1: UUID="972db769-4020-4b74-b943-9b868c26043a" TYPE="ext4"
/dev/sda5: UUID="a3f5d977-72d7-47c9-a059-38633d16413e" TYPE="swap"
/dev/sdb1: UUID="1843f813-872b-44ff-9a4e-38b77976e8dc" TYPE="ext4"
/dev/sdc1: UUID="92dc7073-bf4d-4c58-8052-63129ff5755b" TYPE="ext4"

Added the fstab entry for the backup disk

media>cat /etc/fstab
# /etc/fstab: static file system information.
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    nodev,noexec,nosuid 0       0
# / was on /dev/sda1 during installation
UUID=972db769-4020-4b74-b943-9b868c26043a /               ext4    errors=remount-ro 0       1
# swap was on /dev/sda5 during installation
UUID=a3f5d977-72d7-47c9-a059-38633d16413e none            swap    sw              0       0

#UUID="90a5c98a-22fb-4685-9c17-77ed07a5e000"    /media/40mBackup       ext4      defaults,relatime,commit=60       0         0

# OLD BACKUP DISK as of 2021/09/02
#UUID="1843f813-872b-44ff-9a4e-38b77976e8dc"    /media/40mBackup       ext4      defaults,relatime,commit=60       0         0

# Current backup disk as of 2021/12/22
UUID="92dc7073-bf4d-4c58-8052-63129ff5755b"    /media/40mBackup       ext4      defaults,relatime,commit=60       0         0

#fb:/frames      /frames nfs     ro,bg

# CURRENT MAIN DISK as of 2021/09/02
# UUID=92dc7073-bf4d-4c58-8052-63129ff5755b   /home/cds    ext4    defaults,relatime,commit=60    0   0
UUID="1843f813-872b-44ff-9a4e-38b77976e8dc"   /home/cds    ext4   defaults,relatime,commit=60    0   0

  16534   Wed Dec 22 18:16:23 2021 KojiUpdateSUSRemaining task for 2021

The in-vacuum installation team has reported that the side OSEMs of ITMX and LO1 are going to be interfering if place LO1 at the planned location.
I confirmed that ITMX has the side magnet on the other side (Attachment 1 ITMX photo taken on 2016/7/21). So we can do this swap.

The ITMX side OSEM is sticking out most. By doing this operation, we will recover most of the space between the ITMX and LO1. (Attachment 2)

  16535   Thu Dec 23 16:38:21 2021 KojiUpdateGeneralIs megatron down? (Re: chiara local backup)

The local backup seems working fine again. But I found that megatron is down and this is a real issue. This should be fixed at the earliest chance.

It seems that the local backup has been successfully taken this morning.

controls@nodus|backup> tail /opt/rtcds/caltech/c1/scripts/backup/localbackup.log
2021-12-19 07:00:01,146 INFO       Updating backup image of /cvs/cds
2021-12-19 07:00:01,146 ERROR      External drive not mounted!!!
2021-12-20 07:00:01,255 INFO       Updating backup image of /cvs/cds
2021-12-20 07:00:01,255 ERROR      External drive not mounted!!!
2021-12-21 07:00:01,361 INFO       Updating backup image of /cvs/cds
2021-12-21 07:00:01,361 ERROR      External drive not mounted!!!
2021-12-22 07:00:01,469 INFO       Updating backup image of /cvs/cds
2021-12-22 07:00:01,470 ERROR      External drive not mounted!!!
2021-12-23 07:00:01,594 INFO       Updating backup image of /cvs/cds
2021-12-23 07:19:55,560 INFO       Backup rsync job ran successfully, transferred 338425 files.

However, I noticed that the autoburt has been stalled since Dec 6 (I used to check how the backup is up-to-date using the autoburt snapshots)

Dec>ls -l
total 24
drwxr-xr-x 26 controls controls 4096 Dec  1 23:07 1
drwxr-xr-x 26 controls controls 4096 Dec  2 23:07 2
drwxr-xr-x 26 controls controls 4096 Dec  3 23:07 3
drwxr-xr-x 26 controls controls 4096 Dec  4 23:07 4
drwxr-xr-x 26 controls controls 4096 Dec  5 23:07 5
drwxr-xr-x 19 controls controls 4096 Dec  6 16:07 6

There are a bunch of errors in the log file as follows, but maybe this is not an issue

controls@nodus|burt> pwd
controls@nodus|burt> tail burtcron.log
!!!  ERROR !!! Target c1supepics Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1tstepics Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1x10epics Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1aux Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1dcuepics Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1iscaux Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1iscepics Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1losepics Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1psl Snapshot file inconsistent with Request file
!!!  ERROR !!! Target c1susaux Snapshot file inconsistent with Request file

The real issue seems that megatron is down. It has a lot of house keeping jobs on corn including the N2 pressure alert.
This needs to be fixed at the earliest chance.

  16536   Fri Dec 24 16:49:41 2021 KojiUpdateGeneralIs megatron down? (Re: chiara local backup)

It turned out that the UPS installed on Nov 22 failed (cf https://nodus.ligo.caltech.edu:8081/40m/16479 ). As a fact, it was alive just for 2 weeks!

The APC UPS unit indicated F06. According to the manual (https://www.apc.com/shop/us/en/products/APC-Power-Saving-Back-UPS-Pro-1000VA/P-BR1000G), F06 means "Relay Welding" and can not be fixed by a user. Resetting the UPS eliminated the error, but I didn't want to have the same issue while no one is in the lab, I moved the megatron power source from the UPS to the power strip on 1Y7. So, megatron is currently vulnerable to a power glitch.

After the power cords were restored, megatron eventually recovered ssh terminals. I manually ran autoburt.cron at 16:50 so that the latest snapshot is taken.

  16538   Sun Jan 2 20:46:46 2022 KojiUpdateSUSEnd SUS Electronics building

19:00~ Start working on the electronics bench

The following units were tested and ready to be installed. These are the last SUS electronics units and we are now ready to upgrade the end SUS electronics too.

40m End ADC Adapter Unit D2100016 / 2 Units (S2200001 S2200002)

40m End DAC Adapter Unit D2100647/ 2 Units (S2200003 S2200004)

These are placed on Tega's desk together with the vertex DAC adapters

0:30 End work

  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.

ELOG V3.1.3-