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ID Date Authorup Type Category Subject
  15813   Wed Feb 17 13:59:43 2021 KojiUpdateSUSCoM on 3"->2" Adapter Ring for SOS

Note from today's meeting:

1. Can we adjust the thickness of the cylindrical hole for the mirror to move the COM in the plane of the wires. (We should be able to do that)

and

2. Please check how much we can displace the COM by the bottom dumbbell.

  15815   Thu Feb 18 03:20:09 2021 KojiSummaryElectronicsCurrent Rack Map

For your planning:

  15819   Thu Feb 18 20:20:25 2021 KojiUpdateSUSaLIGO Sat Amp characterization

Yeah, it's really inconsistent. You had 35mA LED drive and the current noise of the noisy channel was 5e-7 A/rtHz at 1Hz. The RIN is 1.4e-5 /rtHz. The approx. received photocurrent is 30uA as we discussed today and this should make the noise around 4e-10 A/rtHz at 1Hz. However, the readout noise level is better than this level. (well below 1e-10 A/rtHz)

BTW, the IMC seemed continuously locked for 5 hours. Good sign.

  15820   Thu Feb 18 20:24:48 2021 KojiSummaryElectronicsA bunch of electronics received

Todd provided us a bunch of electronics. I went to Downs to pick them up this afternoon and checked the contents in the box. Basically, the boxes are pretty comprehensive to produce the following chassis

  • 8 HAM-A coil driver chassis
  • 7 16bit Anti-Aliasing chassis
  • 4 18bit Anti-Imaging chassis
  • 5 16bit Anti-Imaging chassis

Some panels are missing (we cannibalized them for the WFS electronics). Otherwise, it seems that we will be able to assemble these chassis listed.
They have placed inside the lab as seen in the attached photo.


HAM-A COIL DRIVER (Req Qty 28+8)

- 8 Chassis
- 8 Front Panels
- 8 Rear Panels
- 8 HAM-A Driver PCBs
- 8 D1000217 DC Power board
- 8 D1000217 DC Power board

16bit AA (Req Qty 7)
- 7 CHASSIS
- 6 7 Front Panels (1 missing -> [Ed 2/22/2021] Asked Chub to order -> Received on 3/5/2021)
- 7 Rear Panels
- 28 AA/AI board S2001472-486, 499-511
- 7 D070100 ADC AA I/F
- 7 D1000217 DC Power board

18bit AI (Req Qty 4)
- 4 CHASSIS
- 4 Front Panels
- 4 Rear Panels
- 8 AA/AI board S2001463-67, 90-92
- 4 D1000551 18bit DAC AI I/F
- 4 D1000217 DC Power board
- bunch of excess components

16bit AI (Req Qty 5)
- 5 CHASSIS
- 4 5 Front Panels (D1101522) (1 missing -> [Ed 2/22/2021] Asked Chub to order -> Received on 3/5/2021)
- 3 5 Rear Panels (D0902784) (2 missing -> [Ed 2/22/2021] Asked Chub to order -> Received on 3/5/2021)
- 10 AA/AI board S2001468-71, 93-98
- 5 D1000217 DC Power board
- 5 D070101 DAC AI I/F

Internal Wiring Kit

[Ed 2/22/2021]
Asked Chub to order:
- Qty 12 1U Hamilton Chassis
- Qty 5 x Front/Rear Panels/Internal PCBs for D1002593 BIO I/F (The parts and connectors to be ordered separately)

  -> Front/Rear Panels received (3/5/2021)
  -> PCBs (unpopulated) received (3/5/2021)
  -> Components ordered by KA (3/7/2021)

  15824   Fri Feb 19 16:06:01 2021 KojiUpdateSUSCoM Range on 3"->2" Adapter Ring for SOS

We want to move the CoM with the adjustment range so that the residual deviation is adjusted by the bottom dumbbell. 0.0003" is well within the range and good enough.

 

  15826   Fri Feb 19 16:55:26 2021 KojiUpdateSUSCoM Range on 3"->2" Adapter Ring for SOS

Jordan's screenshot actually shows that the vertical distance (Y) is 0.0000". We want to have the vertical distance of CoM from the wire clamping point to be 0.9mm in the nominal SOS design (this might need to be adjusted to have a similar pitch resonant freq for the different inertia of moment). Let's say it is ~mm ish.

The full range of the bottom dumbbell adjustment gives us the CoM adjustment range of +/-0.002” = +/-50um. This corresponds to an alignment range of +/-50mrad. And we want to set it within +/-500urad.
So we need to adjust the dumbbell position with the precision of 1/100 of the full range (precision of 0.5um).

The groove does not extend to the top of the clamp. The groove shallower than the wire diameter cause the hysteresis of the alignment. Also, the material of the pieces should be stainless steel. Al clamp is softer than the wire and will cause the groove to be dug on the material, causing increased bending friction and hysteresis again.

Saying, all of our suspended masses with Al stand-offs are suffering this issue to some extent. That was the reason to buy the ruby standoffs.

  15830   Sat Feb 20 16:46:17 2021 KojiSummaryElectronicsA bunch of electronics received

We received currently available sets. We are supposed to receive more coil drivers and sat amps, etc. But they are not ready yet.

 

  15835   Tue Feb 23 20:55:19 2021 KojiUpdateSUSOSEM testing for SOSs

I can't obtain a consistent view between the existing drawings/photographs and your pin assignment. Please review the pin assignment again to check if yours is correct.

Looking from the back side and the wires are going down, the left bottom pin is "Coil Start" and the upper right adjacent pin is "Coil End". (See attachment)
So in your picture 1 should be the coil start and 4 should be the coil end, but they are not according to your table.

  15836   Tue Feb 23 23:12:37 2021 KojiSummarySUSSUS invacuum wiring

This is my current understanding of the in-vacuum wiring:
1. Facts

  • We have the in-air cable pinout. And Gautam recently made a prototype of D2100014 custom cable, and it worked as expected.
  • The vacuum feedthrough is a wall with the male pins on the both sides. This mirrors pinout.
  • On the in-vacuum cable stand (bracket), the cable has a female connector.

2. From the above facts, the in-vacuum cable is

  • DSUB25 female-female cable
  • There is no pinout mirroring

Accuglass has the DSUB25 F-F cable off-the-shelf. However, this cable mirrors the pinout (see the datasheet on the pdf in the following link)
https://www.accuglassproducts.com/connector-connector-extension-cable-25-way-female

3. The options are
- ask Accuglass to make a twisted version so that the pinout is not mirrored.

or
- combine Accuglass female-male cable (https://www.accuglassproducts.com/connector-connector-extension-cable-25-way-femalemale) and a gender changer (https://www.accuglassproducts.com/gender-adapter-25d)

4. The length will be routed from the feedthrough to the table via the stacks like a snake to be soft. So, it will require some extra length.

5. Also, the Accuglass cables don't have a flap and holes to fix the connector to a cable post (tower). If we use a conventional 40m-style DSUB25 post (D010194), it will be compatible with their cables. But this will not let us use a DSUB25 male connector to mate. In the future, the suspension will be upgraded and we will need an updated cable post that somehow holds the connectors without fastening the screws...

  15847   Fri Feb 26 20:20:43 2021 KojiUpdateElectronicsProduction version of the HV coil driver tested with KEPCO HV supplies

This is very disappointing. Even with KEPCO linear supply with the improved HV driver circuit, the noise level is significantly higher than the 20kOhm R thermal noise.

What is special with the HP supplies? Can you replace KEPCOs with the HP supply, one by one to specify which one is making the noise bad?

  15863   Thu Mar 4 15:48:26 2021 KojiSummaryPEMWatchdog tripped, Optics damped back

EQs seen on Summary pages
https://nodus.ligo.caltech.edu:30889/detcharsummary/day/20210304/pem/seismic_blrms/

  15864   Thu Mar 4 23:16:08 2021 KojiUpdateLSCREFL55 demod board rework

A new hybrid splitter (DQS-10-100) was installed. As the amplification of the final stage is sufficient for the input level of 3dBm, I have bypassed the input amplification (Attachment 1). One of the mixer was desoldered to check the power level. With a 1dB ATTN, the output of the last ERA-5 was +17.8dBm (Attachment 2). (The mixer was resoldered.)

With LO3dBm. RF0dBm, and delta_f = 30Hz, the output Vpp of 340mV and the phase difference is 88.93deg. (Attachment 3/4, the traces were averaged)

  15865   Thu Mar 4 23:57:35 2021 KojiSummaryElectronicsInspection of the new custom dsub cables

I made the inspection of the new custom DSub cables (came from Texas).

The shelled version gives us some chance to inspect/modify the internal connections. (good)
The wires are well insulated. The conductors are wrapped with the foils and then everything is in the braid tube shield. The braid is soldered on one of the connectors. (Attachment  3/4 shows the soldering of the conductor by intentionally removing one of the insulations).

It wasn't clear that if the conductors are twisted or not (probably not).

  15866   Fri Mar 5 00:53:09 2021 KojiSummaryElectronicsA bunch of electronics received

Received additional front/rear panels. Updated the original entry and Wiki [Link]

 

  15869   Fri Mar 5 15:31:23 2021 KojiUpdateLSCREFL55 demod board rework

Missed to note: The IF test was done at TP7 and TP6 using pomona clips i.e. brefore the preamp.

 

  15870   Fri Mar 5 15:32:53 2021 KojiSummaryElectronicsA bunch of electronics received

The parts will be ordered by Koji The components for the additional BIO I/F have been ordered.

  15885   Tue Mar 9 12:41:29 2021 KojiSummaryElectronicsInvestigation on the invacuum Dsub cables

I believe the aLIGO style invac dsub cables and the conventional 40m ones are incompatible.
While the aLIGO spec is that Pin1 (in-vac) is connected to the shield, Pin13 (in-vac) is the one for the conventional cable. I still have to check if Pin13 is really connected to the shield, but we had trouble before for the IO TTs https://nodus.ligo.caltech.edu:8081/40m/7864.
(At least one of the existing end cables did not show this Pin13-chamber connection. However, the cables OMC/IMC chambers indicated this feature. So the cables are already inhomogenious.)

- Which way do we want to go? Our electronics are updated with aLIGO spec (New Sat amp, OMC electronics, etc), so I think we should start making the shift to the aLIGO spec.

- Attachment Top: The new coil drivers can be used together with the old cables using a custom DB25 cable (in-air).

- Attachment Mid: The combination of the conventional OSEM wiring and the aLIGO in-vac cable cause the conflict. The pin1 which is connected to the shield is used for the PD bias.

- Attachment Bottom: This can be solved by shifting the OSEMs by one pin.

Notes:
o The aLIGO cables have 12 twisted pair wires, but paired signals do not share a twisted pair.
   --- No. This can't be solved by rotating the connectors.
o This modification should be done only for the new suspension.
   --- In principle, we can apply this change to any SOSs. However, this action involves the vent. We probably want to install the new electronics for the existing suspensions before the vent.
o ^- This means that we have to have two types of custom DB25 in-air cables.
   --- Each cable should handle "Shield wire" from the sat amp correctly.

Related Links:

Active TT Pin Issue
https://nodus.ligo.caltech.edu:8081/40m/7863
and the thread

Hacky solution
https://nodus.ligo.caltech.edu:8081/40m/7869

Photo
https://photos.google.com/u/1/album/AF1QipOEDi7iBdS4EHcpM7GBbv9l6FiJx-Tkt1I2eSFA
Active TT Pin Swapping (December 21, 2012)

TT Wiring Diagram (Wiki)
https://wiki-40m.ligo.caltech.edu/Suspensions/Tip_Tilts_IO

  15888   Tue Mar 9 15:19:03 2021 KojiUpdateSUSOSEM testing for SOSs

How were the statistics of them? i.e. # of Good OSEMs, # of OK OSEMs, etc...

  15889   Tue Mar 9 15:22:56 2021 KojiSummarySUSPRM suspension

I just saw the PRM watchdog tripped at ~15:20 local (23:20UTC). I restored the PRM but I saw only the side watchdog tripped.
Again at 15:27

17:55 I found the PRM was oscillating while the watchdogs were not tripped. I turned off the OPLEV servos and this made the PRM calmed down. But I didn't turn on the OPLEVs for the past two trips. How were the OPLEVs turned on???

Ah, I'm sorry, I missed the line that Gautam was running the free-swinging test on the PRM.
The two kicks starting from 23:08:50 and from 23:26:31 were spoiled. Did it make the measurement completely waisted?

 

  15901   Thu Mar 11 02:10:06 2021 KojiSummaryBHDBHD Platform vertical dimentions

Stephen and I discussed the nominal heights of the BHD platform components.

  • The beam height from the stack is 5.5"
  • The platform height is 1.5" and the thickness of 0.4", according to the VOPO suspension, which we want to be compatible with.
  • Thus the beam height on the BHD platform is 4".
  • The VOPO platform has a minimum 0.1" gap from the installation surface when it is suspended.
  • When the BHD platform is fixed on the table, we'll use positioners that are fixed on the stack table. Then the BHD platform is fixed on the positioner rather than fixing the entire platform on the stack. This leaves us the option to suspend the platform in the future. The number of the positioners is TBD.
  • Looking at the head size for 1/4-20 socket head screws, It'd be nice to have the thickness of 0.5" for the positioners. This makes the thin part of the stiffener to be 0.6" in thickness.
     
  • The numbers are nominal for the initial design and subject to the change along with FEA simulations to determine the resonant frequency of the body modes.
  15907   Fri Mar 12 03:08:23 2021 KojiSummarySUSCoil Rs & Ls for PRM/BS/SRM

Summary

Per Gautam's request, I've checked the coil resistances and inductances.

  • PRM/BS/SRM coils were tested.
  • All the PRM coils look well-matched in terms of the inductance. Also, I didn't find a significant difference from BS coils.
  • Pin 1 of the feedthru connectors is shorted to the vacuum chamber.
  • A discovery was that: The SRM DSUB pinouts are mirrored compared to the other suspensions.

Method

A DSUB25 breakout was directly connected to the flange (Attachment 1).
The impedance meter was nulled every time the measurement range and type (R or L) were changed.

Result

Feedthru connector: PRM1
Pin1 - flange: R = 0.8Ω
Pin11-23 / R = 1.79Ω / L=3.21mH
Pin 7-19 / R = 1.82Ω / L=3.22mH
Pin 3-15 / R = 1.71Ω / L=3.20mH

Feedthru connector: BS1
Pin1 - flange: R = 0.5Ω
Pin11-23 / R = 1.78Ω / L=3.26mH
Pin 7-19 / R = 1.63Ω / L=3.30mH
Pin 3-15 / R = 1.61Ω / L=3.29mH

Feedthru connector: SRM1
Pin1 - flange: R = 0.5Ω

Pin11-24 / R = 18.1Ω / L=3.22mH
Pin 7-20 / R = 18.8Ω / L=3.25mH
Pin 3-16 / R = 20.3Ω / L=3.25mH

Feedthru connector: PRM2
Pin1 - flange: R = 0.6Ω
Pin11-23 / R = 1.82Ω / L=3.20mH
Pin 7-19 / R = 1.53Ω / L=3.20mH
Pin 3-15 / R = N/A

Feedthru connector: BS2
Pin1 - flange: R = 0.6Ω
Pin11-23 / R = 1.46Ω / L=3.27mH
Pin 7-19 / R = 1.54Ω / L=3.24mH
Pin 3-15 / R = N/A

Feedthru connector: SRM2
Pin1 - flange: R = 0.7Ω
Pin11-24 / R = N/A

Pin 7-20 / R = 18.5Ω / L=3.21mH
Pin 3-16 / R = 19.1Ω / L=3.25mH

Observation

The SRM pinouts seem mirrored compared to the others. In fact, these two connectors are equipped with mirror cables (although they are unshielded ribbons) (Attachment 2).

The SRM sus is located on the ITMY table. There is a long in vacuum DSUB25 cable between the ITMY and BS tables. I suspect that the cable mirrors the pinout and this needs to be corrected by the in-air mirror cables.

I went around the lab and did not find any other suspensions which have the mirror cable.

WIth the BHD configuration, we will move the feedthru for the SRM to the one on the ITMY chamber. So I believe the situation is going to be improved.

 

  15908   Fri Mar 12 03:22:45 2021 KojiUpdateGeneralGaussmeter in the electronics drawer

For magnet strength measurement: There is a gaussmeter in the flukes' drawer (2nd from the top). It turns on and reacts to a whiteboard magnet.

  15909   Fri Mar 12 03:23:37 2021 KojiUpdateBHDDO card (DO-32L-PE) brought from WB

I've brought 4 DO-32L-PE cards from WB for BHD upgrade for Jon.

  15910   Fri Mar 12 03:28:51 2021 KojiUpdateCDScds reboot

I want to emphasize the followings:

  • FB's RTC (real-time clock/motherboard clock) is synchronized to NTP time.
  • The other RT machines are not synchronized to NTP time.
  • My speculation is that the RT machine timestamp is produced from the local RT machine time because there is no IRIG-B signal provided. -> If the RTC is more than 1 sec off from the FB time, the timestamp inconsistency occurs. Then it induces "DC" error.
  • For now, we have to use "date" command to match the local RTC time to the FB's time.
     
  • So: If NTP synchronization is properly implemented for the RT machines, we will be free from this silly manual time adjustment.

 

  15923   Tue Mar 16 16:02:33 2021 KojiUpdateLSCREFL11 demod retrofitting

I'm going to remove REFL11 demod for the noise check/circuit improvement.

----

  • The module was removed (~4pm). Upon removal, I had to loosen AS110 LO/I out/Q out. Check the connection and tighten their SMAs upon restoration of REFL11.
  • REFL11 configuration / LO: see below, PD: a short thick SMA cable, I OUT: Whitening CH3, Q OUT: Whitening CH4, I MON daughterboard: CM board IN1 (BNC cable)
  • The LO cable for REFL11 was made of soft coax cable (Belden 9239 Low Noise Coax). The vendor specifies that this cable is for audio signals and NOT recommended for RF purposes [Link to Technical Datasheet (PDF)].
    I'm going to measure the delay of the cable and make a replacement.
  • There is a bunch of PD RF Mon cables connected to many of the demo modules. I suppose that they are connected to the PD calibration system which hasn't been used for 8 years. And the controllers are going to be removed from the rack soon.
    I'm going to remove these cables.

----

First I checked the noise levels and the transfer functions of the daughterboard preamp were checked. The CH-1 of the SR785 seemed funky (I can't comprehensively tell yet how it was), so the measurement maybe unreliable.

For the replacement of AD797, I tested OP27 and TLE2027. TLE2027 is similar to OP27, but slightly faster, less noisy, and better in various aspects.

The replacement of the AD797 and whatever-film resistors with LTE2027 and thin-film Rs were straightforward for the I phase channel, while the stabilization of the Q phase channel was a struggle (no matter I used OP27 or TLE2027). It seems that the 1st stage has some kind of instability and I suffered from 3Hz comb up to ~kHz. But the scope didn't show obvious 3Hz noise.

After a quite bit of struggle, I could tame this strange noise by adjusting the feedback capacitor of the 1st stage. The final transfer functions and the noise levels were measured. (To be analyzed later)

----

Now the REFL11 LO cable was replaced from the soft low noise audio coax (Belden 9239) to jacketed solder-soaked coax cable (Belden 1671J - RG405 compatible). The original cable indicated the delay of -34.3deg (@11MHz, 8.64ns) and the loss of 0.189dB.

I took 80-inch 1671J cable and measured the delay to be ~40deg. The length was adjusted using this number and the resulting cable indicated the delay of -34.0deg (@11MHz, 8.57ns) and the loss of 0.117dB.

The REFL11 demod module was restored and the cabling around REFL11 and AS110 were restored, tightened, and checked.

----

I've removed the PD mon cables from the NI RF switch. The open ports were plugged with 50Ohm temirnators.

----

I ask commissioners to make the final check of the REFL11 performance using CDS.

  15936   Thu Mar 18 07:02:27 2021 KojiUpdateLSCREFL11 demod retrofitting

Attachment 1: Transfer Functions

The original circuit had a gain of ~20 and the phase delay of ~1deg at 10kHz, while the new CH-I and CH-Q have a phase delay of 3 deg and 2 deg, respectively.

Attachment 2: Output Noise Levels

The AD797 circuit had higher noise at low frequency and better noise levels at high frequency. Each TLE2027 circuit was tuned to eliminate the instability and shows a better noise level compared to the low-frequency spectrum of the AD797 version.

RXA: AD797 sad, all hail the op-amps ending with 27 !

  15980   Wed Mar 31 00:40:32 2021 KojiUpdateElectronicsElectronics Packaging for assembly work

I've worked on packing the components for the following chassis
- 5 16bit AI chassis
- 4 18bit AI chassis
- 7 16bit AA chassis
- 8 HAM-A coil driver chassis
They are "almost" ready for shipment. Almost means some small parts are missing. We can ship the boxes to the company while we wait for these small parts.

  • DB9 Female Ribbon Receptacle AFL09B-ND Qty100 (We have 10) -> Received 90 on Apr 1st
  • DB9 Male Ribbon Receptacle CMM09-G Qty100 (We have 10) -> Received 88 on Apr 1st
  • 4-40 Pan Flat Head Screw (round head, Phillips) 1/2" long Qty 50 -> Found 4-40 3/8" Qty50 @WB EE on Apr 1st (Digikey H782-ND)
  • Keystone Chassis Handle 9106 36-9106-ND Qty 50 -> Received 110 on Apr 1st
  • Keystone Chassis Ferrule 9121 NKL PL 36-9121-ND Qty 100 -> Received 55 on Apr 1st
  • Chassis Screws 4-40 3/16" Qty 1100 -> Received 1100 on Apr 1st
  • Chassis Ear Screws 6-32 1/2" 91099A220 Qty 150 -> Received 400 of 3/8" on Apr 1st
  • Chassis Handle Screws 6-32 1/4" 91099A205 Qty 100 -> included in the above
  • Powerboard mounting screw 4-40 Pan Flat Head Screw (round head, Phillips) 1/4" long Qty 125 -> Received 100 on Apr 1st

And some more additional items to fill the emptying stock.

  • 18AWG wires (we have orange/blue/black 1000ft, I'm sending ~1000ft black/green/white)
  • Already consumed 80% of 100ft 9pin ribbon cable (=only 20ft left in the stock)
  15981   Wed Mar 31 03:56:37 2021 KojiSummaryElectronicsA bunch of electronics received

We have received 9x 18bit DAC adapter boards (D1000654)

  15986   Thu Apr 1 18:16:28 2021 KojiUpdateElectronicsElectronics Packaging for assembly work

All small components are packed in the boxes. They are ready to ship.

 

  15989   Thu Apr 1 23:55:33 2021 KojiSummaryGeneralHEPA AC cord replacement

I think the PSL HEPA (both 2 units) are not running. The switches were on. And the variac was changed from 60% to 0%~100% a few times but no success.
I have no troubleshooting power anymore today. The main HEPA switch was turned off.

  16002   Tue Apr 6 21:17:04 2021 KojiSummaryGeneralPSL HEPA investigation

- Last week we found both of the PSL HEPA units were not running.

- I replaced the capacitor of the north unit, but it did not solve the issue. (Note: I reverted the cap back later)
- It was found that the fans ran if the variac was removed from the chain.
- But I'm not certain that we can run the fans in this configuration with no attendance considering fire hazard.

@3AM: UPON LEAVING the lab, I turned off the HEPA. The AC cable was not warm, so it's probably OK, but we should wait for the continuous operation until we replace the scorched AC cable.


The capacitor replacement was not successful. So, the voltages on the fan were checked more carefully. The fan has the three switch states (HIGH/OFF/LOW). If there is no load (SW: OFF), the variac out was as expected. When the load was LOW or HIGH, it looked as if the motor is shorted (i.e. no voltage difference between two wires).

I thought the motors may have been shorted. But if the load resistance was measured with the fluke meter, it showed some resistance

- North Unit: SW LOW 4.6Ohm / HIGH 6.0Ohm
- South Unit: SW LOW 6.0Ohm / HIGH 4.6Ohm (I believe the internal connection is incorrect here)

I believed the motors are alive! Then the fans were switched on with the variac removed... they ran. So I set the switch LOW for the north unit and HIGH for the south unit.

Then I inspected the variac:

  • The AC output has some liquid leaking (oil?) (Attachment 1)
  • The AC plug on the variac out has a scorch mark (Attachments 2/3)

So, this scorched AC plug/cable connected directly to the AC right now. I'm not 100% confident about the safety of this configuration.
Also I am not sure what was wrong with the system.

  • Has the variac failed first? Because of the heat? I believe that the HEPA was running @30% most of the time. Maybe the damage was already there at the failure in Nov 2020?
  • Or has the motor stopped at some point and this made the variac failed?
  • Was the cable bad and the heat made the variac failed (then the problem is still there).

So, while I'm in the lab today, I'll keep the HEPA running, but upon my taking off, I'll turn it off. We'll discuss what to do in the meeting tomorrow.

 

  16003   Wed Apr 7 02:50:49 2021 KojiUpdateSUSFlange Inspections

Basically I went around all the chambers and all the DB25 flanges to check the invac cable configurations. Also took more time to check the coil Rs and Ls.

Exceptions are the TTs. To avoid unexpected misalignment of the TTs, I didn't try to disconnect the TT cables from the flanges.

Upon the disconnection of the SOS cables, the following steps are taken to avoid large impact to the SOSs

  • The alignment biases were saved or recorded.
  • Gradually moved the biases to 0
  • Turned off the watchdogs (thus damping)

After the measurement, IMC was lock and aligned. The two arms were locked and aligned with ASS. And the PRM alignment (when "misalign" was disengaged) was checked with the REFL CCD.
So I believe the SOSs are functioning as before, but if you find anything, please let me know.
 

  16008   Thu Apr 8 20:58:17 2021 KojiUpdateCDSADC adapter boards assembly

5x 16bit ADC adapter boards (D0902006) assembled.

  16038   Thu Apr 15 18:33:39 2021 KojiUpdateCDSMore 16bit ADC adapter boards

We received 10x 16bit ADC adapter boards from Todd. S2100687~S2100696

The number of soldered resistors seems to be less than that on the schematics. They are related to duotone, so check if it's OK upon use.

  16039   Fri Apr 16 00:21:52 2021 KojiUpdateGeneralGlue Freezer completely frozen

I was looking at the laser head/amp and somehow decided to open the glue freezer. And it was stuck. I've managed to open it but the upper room was completely frozen.
Some of the batteries were embedded in a block of ice. I think we should throw them out.

Can the person who comes in the morning work on defrosting?

- Coordinate with Yehonathan and move the amps and the wooden crate so that you can move the freezer.

- Remove the contents to somewhere (it's OK to be room temp for a while)

- Unplug the freezer

- Leave the freezer outside with the door open. After a while, the ice will fall without care.

- At the end of the day, move it back to the lab. Continue defrosting the other day if the ice remains.

  16056   Wed Apr 21 00:08:15 2021 KojiUpdatePSLPSL Table (sort of) covered / HEPA "chimney"

Shutdown Procedure:
PSL Shutter closed / MC Autolocker disabled / PSL mechanical shutter closed / Laser injection current turned to zero / Laser turn off (red button) / Laser key turned off

The laser stat before the shutdown:
- LD Temp A: Set 22.07 (Untouched)
- LD Temp B: Set 21.03(Untouched)
- Laser Injection Current: Dial 9.53, Actual 2.100 -> Dial was moved to zero upon shutting down
- Laser Crystal Temp: Dial 3.34 (untouched)  Set 30.57 Actual 30.60 (Untouched)

PSL Table covering

- Because of the so many cables going up and down, sealing the PSL table with the metalized sheet was not easy. Therefore, the sheets have been just softly laid above the optics. (Attachment 1)
- The largest sheet which covers the east half of the table was taped to the table at the bottom, so that the air from the chimneys (see below) does not come up to the table

- The large dust could come from the opening of the enclosure during the filter replacement. So it was considered to be easier to seal the openings. (Attachment 2)
- Of course, the HEPAs are going to be tested after the maintenance work. It means that vent paths were needed so that the seals do not explode with the pressure (together with dust).
- Thus, the tubes of the sheets are attached to the seals to form "chimneys" for guiding the airflow beneath the table. (Attachment 2/3/4)
- This configuration was not meant to be sufficiently strong for a continuous run of the fans. Long running of the HEPAs may cause the failure of the seal tapes.
  Therefore the HEPA test should be done with a low flow rate and/or a short period of high flow.

- Once the work has been done, all the sheets should be carefully removed without scattering the fallouts onto the optics.

 

  16057   Wed Apr 21 01:14:03 2021 KojiUpdatePSLPSL Table (sort of) covered / HEPA "chimney"

I also located the (possible) HEPA filters in the lab. (Attachments 1~3)

Oh! This is NO-NO! We can't place anything in front of the mains breakers. (Attachment 2)
I relocated the objects (Attachment 3)

 

  16065   Wed Apr 21 13:10:12 2021 KojiUpdateGeneralPSL HEPA Maintenance

It's probably too late to say but there are/were two boxes. (just for record)

 

  16069   Wed Apr 21 19:43:20 2021 KojiUpdatePSLNew HEPA speed control

The new HEPA speed controllers are attached at the middle of the HEPA unit (not at the edge of the unit)... (Attachment 1)
You still need a step./stool to touch the knob and need a ladder for a more precise setting.

We still don't know the optimal speed of the nominal IFO operation. For now, the HEPAs are running at the max speed (Attachment 2).
Once we know the optimal setting, we mark the knobs so that we can see them only with the step.

  16070   Thu Apr 22 01:42:38 2021 KojiSummaryElectronicsHV Supply Comparison

New HV power supply from Company 'M' has been delivered. So I decided to compare the noise levels of some HV supplies in the lab. There are three models from companies 'H', 'K', and 'M'.

The noise level was measured with SR785 via Gautam's HP filter with protection diodes.

'H' is a fully analog HV supply and the indicator is analog meters.
'K' is a model with a LCD digital display and numerical keypad.
'M' is a model with a knob and digital displays.

All the models showed that the noise levels increased with increased output voltage.

Among these three, H showed the lowest noise. (<~1uV/rtHz@10Hz and <50nV/rtHz@100Hz) (Attachment 1)

K is quite noisy all over the measured freq range and the level was <50uV/rtHz. Also the PSD has lots of 5Hz harmonics. (Attachment 2)

M has a modest noise level (<~30uV/rtHz@10Hz and <1uV/rtHz@100Hz)except for the noticeable line noise (ripple). (Attachment 3)

The comparison of the three models at 300V is Attachment 4. The other day Gautam and I checked the power spectrum of the HV coil driver with KEPCO and the output noise level of the coil driver was acceptable. So I expect that we will be able to use the HV supply from Company M. Next step is to check the HV driver noise with the model by M used as the supply.

  16083   Fri Apr 23 19:26:58 2021 KojiUpdatePSLHEPA speed lowered

I believe that there is an internal setting for the minimum flow, so the flow is not linear ("0%" is not zero), but we should mark this flow speed once you find this is sufficiently low for the locking too.

  16099   Thu Apr 29 17:43:16 2021 KojiUpdateCDSRFM

The other day I felt hot at the X end. I wondered if the Xend A/C was off, but the switch right next to the SP table was ON (green light).
I could not confirm if the A/C was actually blowing or not.

  16115   Mon May 3 23:28:56 2021 KojiSummaryGeneralWeird gas leakagr kind of noise in 40m control room

I also noticed some sound in the control room. (didn't open the MP3 yet)

I'm afraid that the hard disk in the control room iMac is dying.

 

  16131   Tue May 11 17:43:09 2021 KojiUpdateCDSI/O Chassis Assembly

Did you match the local PC time with the GPS time?

  16136   Wed May 12 16:53:59 2021 KojiUpdateSUSMass Properties of SOS Assembly with 3"->2" Optic sleeve, in SI units

No, this is the property of the suspension assembly. The mass says 10kg

Could you do the same for the testmass assembly (only the suspended part)? The units are good, but I expect that the values will be small. I want to keep at least three significant digits.

  16140   Fri May 14 03:29:50 2021 KojiUpdateElectronicsHV Driver noise test with the new HV power supply from Matsusada

I believe I did the identical test with the one in [40m ELOG 15786]. The + input of PA95 was shorted to the ground to exclude the noise from the bias input. The voltage noise at TP6 was measured with +/-300V supply by two HP6209 and two Matsusada R4G360.

With R4G360, the floor level was identical and 60Hz line peaks were less. It looks like R4G360 is cheap, easier and precise to handle, and sufficiently low noise.

  16146   Wed May 19 18:29:41 2021 KojiUpdateSUSMass Properties of SOS Assembly with 3"->2" Optic sleeve, in SI units

Calculation for the SOS POS/PIT/YAW resonant frequencies

- Nominal height gap between the CoM and the wire clamping point is 0.9mm (cf T970135)

- To have the similar res freq for the optic with the 3" metal sleeve is 1.0~1.1mm.
As the previous elog does not specify this number for the current configuration, we need to asses this value and the make the adjustment of the CoM height.

  16148   Thu May 20 16:56:21 2021 KojiUpdateElectronicsProduction version of the HV coil driver tested with KEPCO HV supplies

HP HV power supply ( HP6209 ) were returned to Downs

  16149   Fri May 21 00:05:45 2021 KojiUpdateSUSNew electronics: Sat Amp / Coil Drivers

11 new Satellite Amps were picked up from Downs. 7 more are coming from there. I have one spare unit I made. 1 sat amp has already been used at MC1.

We had 8 HAM-A coil drivers delivered from the assembling company. We also have two coil drivers delivered from Downs (Anchal tested)

  16150   Fri May 21 00:15:33 2021 KojiUpdateElectronicsDC Power Strip delivered / stored

DC Power Strip Assemblies delivered and stored behind the Y arm tube (Attachment 1)

  • 7x 18V Power Strip (Attachment 2)
  • 7x 24V Power Strip (Attachment 2)
  • 7x 18V/24V Sequencer / 14x Mounting Panel (Attachment 3)
  • DC Power Cables 3ft, 6ft, 10ft (Attachments 4/5)
  • DC Power Cables AWG12 Orange / Yellow (Attachments 6/7)

I also moved the spare 1U Chassis to the same place.

  • 5+7+9 = 21x 1U Chassis (Attachments 8/9)

 

ELOG V3.1.3-