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ID Date Author Type Category Subjectdown
  12297   Wed Jul 13 00:38:25 2016 JohannesUpdateGeneralVent progress - ETMY attempted repositioning

[Lydia, Johannes]

We attempted to move the ETMY suspension near the access port in preparation for the cleaning process. The plan was to move in the face restraints first to the point of almost making contact, then the ones underneath so the optic is sitting on them, followed by the top one facing down, and then bringing in the stops on the faces.

While moving in the stoppers I noticed that the far lower stopper on the HR side was barely touching the face of the optic in its resting position and was basically pushing it sideways when moved forward. It was just on the edge, so I tried to compensate minimally by moving the underneath stops a little further on the near side, trying to let it 'slide' over a little so the screw would have better contact. I must have been too generous with the adjustment, because while proceeding I noticed at some point that the stick magnets on one side of the optic were not attached anymore but laying inside the OSEMs. The side magnet was also missing, it is now sitting on the suspension jig base plate. The dumbbells all seem intact, but we'll test them before we reglue the magnets to the optic. This is extremely unfortunate, but hopefully won't take too long to fix. At the very least, as Koji put it, the cleaning will be easier with the optic out of the suspension. Still, what a bummer.

  12310   Tue Jul 19 13:21:42 2016 JohannesUpdateGeneralVent progress - ETMY attempted repositioning

[Lydia, Johannes]

We moved ITMY from its original position to a place near the access point. We took the OSEMs off first, and noticed that the short flat head screw driver was still a little too long to properly reach the set screws for the lower OSEMs. We were able to gradually loosen them, though and thus remove the lower OSEMs as well. We had to move a cable tower out of the way, but used clamps to mark its position. After making sure the optic is held by its earthquake stops, we moved it to its cleaning location. All magnets are still attached.

  12247   Tue Jul 5 23:38:42 2016 gautamUpdateGeneralVent progress - ETMX SUS Coil driver electronics investigation

With Koji's help, I've hacked together an arrangement that will allow us to monitor the output of the coil driver to the UL coil. 

The arrangement consists of a short custom ribbon cable with female DB25 connectors on both ends - the particular wire sending the signal to the UL coil has a 100 ohm resistor wired in series, because the coil has resistance ~20ohm, and the output of the coil driver board has a series 200(?) ohm resistor, so by directly monitoring the voltage at this point, we may not see a glitch as it may register too small. Tangentially related: the schematic of the coil driver board suggests that the buffered output monitor has a gain of 0.5. 

To monitor the voltage, I use the board to which the 4 Oplev signals are currently hooked up. Channel 7 on this particular board (corresponding to ADC channel 30 on c1scx) was conveniently wired up for some prior test, so I used this channel. Then, I modified the C1SCX model to add a testpoint to monitor the output of this ADC. Then, I turned OFF the input on the coil output filter for the UL Coil (i.e. C1:SUS-ETMX_ULCOIL_SW1) so that we can send a known, controlled signal to the UL Coil by means of awggui. Next, I added an excitation at 5 Hz, amplitude 20 counts (as the signal to the coil under normal conditions was approximately of this amplitude) to the excitation channel of the same filter module, which is the state I am leaving the setup in for the night. I have confirmed that I see this 5Hz oscillation on the monitor channel I set up. Oddly, the 0 crossings of the oscillations happen at approximately -1000 counts and not at 0 counts. I wonder where this offset is coming from? The two points I am monitoring the voltage across is shown in the attached photograph - the black clip is connected to the lead carrying the return signal from the coil.

I also wanted to set up a math block in the model itself that monitors, in addition to the raw ADC channel, a copy from which the known applied signal has been cancelled, as presumably a glitch would be more obvious in such a record. However, I was unable to access the excitation channel to the ULCOIL filter from within the SCX model. So I am just recording the raw output for tonight...

Attachment 1: image.jpeg
image.jpeg
  12261   Wed Jul 6 22:58:01 2016 gautamUpdateGeneralVent progress - ETMX SUS Coil driver electronics investigation

I've made a few changes to the monitoring setup in the hope we catch a glitch in the DAC output/ sus coil driver electronics. Summary of important changes:

  1. I'm using a CDS oscillator to send a signal of 20counts amplitude, 5.0 Hz to the coil rather than an excitation point. This way, I have access to the known signal we are sending, and can subtract it from the measured signal. 
  2. To account for the phase delay between the excitation from the oscillator to the measured excitation, I am using an all-pass filter to manually delay the oscillator signal (internally in the model) before subtracting it from the measured output.

It remains to see if we will actually be able to see the glitch in long stretches of data - it is unclear to me how big a glitch will be in terms of ADC counts.

The relevant channels are : C1:SCX-UL_DIFF_MON and C1:SCX-UL_DIFF_MON_EPICS (pardon the naming conventions as the setup is only temporary after all). Both these should be hovering around 0 in the absence of any glitching. The noise in the measured signal seems to be around 2 ADC counts. I am leaving this as is overnight, hopefully the ETMX coil drive signal chain obliges and gives us some conclusive evidence...

I have not committed any of the model changes to the SVN. 

  12263   Thu Jul 7 00:25:07 2016 ericqUpdateGeneralVent progress - ETMX SUS Coil driver electronics investigation

It may be advantageous to look at the coil output data from when the OSEM damping is on, to try and reproduce the real output signal amplitude that gets sent to the coils.

  12265   Thu Jul 7 10:49:03 2016 gautamUpdateGeneralVent progress - ETMX SUS Coil driver electronics investigation
Quote:

It may be advantageous to look at the coil output data from when the OSEM damping is on, to try and reproduce the real output signal amplitude that gets sent to the coils.

The amplitude of the applied signal (20) was indeed chosen to roughly match what goes to the coils normally when the OSEM damping is on.

There appears to be no evidence of a detectable glitch in the last 10 hours or so (see attachment #1 - of course this is a 16Hz channel and the full data is yet to be looked at)... I guess the verdict on this is still inconclusive.

Attachment 1: UL_glitchMon_Striptool.png
UL_glitchMon_Striptool.png
  12271   Fri Jul 8 11:35:45 2016 gautamUpdateGeneralVent progress - ETMX SUS Coil driver electronics investigation

Yesterday, I expanded the extent of the ETMX suspension coil driver investigation. I set up identical monitors for two more coils (so now we are monitoring the voltage sent to UL, UR and LL - I didn't set one up for LR because it is on a second DB25 connector). Furthermore, I increased the excitation amplitude from ~20 to ~2000 (each coil had an independent oscillator at slightly different frequency between 5Hz and 8.5 Hz), the logic being that during LSC actuation we send signals of approximately this amplitude to the coils and we wanted to see if a larger amplitude signal somehow makes the system more prone to glitches.

Over ~10 hours of observation, there is no clear evidence of any glitch. About 2 hours ago (~930am PDT Fri Jul 8), the watchdog tripped - but this was because even though I had increased the trip threshold to ~800 for the course of this investigation, megatron runs this script every 20 minutes or so that automatically reduces this threshold by 17 counts - so at some point, the threshold went lower than the coil voltage, causing the watchdog to trip. So this was not a glitch. The other break around 2am PDT earlier today was an FB crash.

Do we now go ahead and pull the suspension out, and proceed with the swap?

Attachment 1: coilGlitchMon.png
coilGlitchMon.png
  12272   Fri Jul 8 11:48:09 2016 KojiUpdateGeneralVent progress - ETMX SUS Coil driver electronics investigation

YES

Move the suspension on the south clean bench and make more close inspection. We need to remove the OSEMs.

Then unmount the mirror. Bring it to the clean room and work on the bond removal.
Meanwhile, set up all suspension components inclusing the alignment test setup.

  12281   Fri Jul 8 21:22:38 2016 gautamUpdateGeneralVent progress - ETMX SUS Coil driver electronics investigation

While ETMX is out, I'm leaving the larger amplitude excitations to the coils on over the weekend, in case any electronic glitch decides to rear its head over the weekend. The watchdog should be in no danger of tripping now that we have removed the ETM.

Unrelated to this work: while removing the ETMX suspension from the chamber, I also removed the large mirror that was placed inside to aid photo taking, so that there is no danger of an earthquake knocking it over and flooding the chamber with dust.

  8929   Fri Jul 26 22:45:14 2013 manasaUpdateGeneralVent progress

[Koji, Manasa]

The arms were brought back to resonance after yesterday's vent work.
DCPD gains were changed (TRX gain from -0.002 to -0.04; TRY gain changed from 0.002 to 0.04) to lock the arm with low power. 
 
X arm and Y arm were locked for IR.

We then decided to align IPANG because the input pointing seemed good - the right time to fix IPANG. The IPANG spot at the last in-vac steering mirror was aligned to be an inch low in pitch.
 
We then aligned SRC. SR2 and SR3 were adjusted to center the beam at SRM. SRM was aligned to the retro-reflected beam until we saw flashes. But this position of SRM is not at the good OSEM range. We should correct the SRM suspensions. We postponed this activity for next week and went ahead to look at the status of the AS beam.
 
Looking through the window and using IR viewer were not convincing enough. We will have to get the access connector out on Monday to do the AS alignment.
We then closed the chamber with light doors and locked the arm cavities again. We brought SRC and PRC to resonance and saw strong flashes at the BS_PRM camera. 
 
To do:
SRM need to be moved in order to remove the big bias in yaw
SRM OSEMS need to be adjusted
Access connector should come out
AS needs to be aligned satisfactorily
ITMX oplev steering mirrors in vacuum should be checked.
  8936   Tue Jul 30 00:21:15 2013 KojiUpdateGeneralVent progress

[Koji, Manasa, Sujan] 

Tomorrow we'll make final checks of the optics inside the chamber.
Then we will pump down the chamber.

- AS beam steering
The AS beam was aligned on the steering mirror (Piezo Jenna i.e. PZT4).
At this point we already found the beam on the AS CCD.
After checking the spots in the OMC chamber, we determined the beam is not clipped inside.
 
On the AS table, there is a weird thick lens with short focal length (like f=37.5mm), this actually clipped the beam significantly
[I take the blame for it from the last vent. The lens was installed thinking it would be temporary which it was not. -Manasa].
We removed this lens and put the CCD camera back so that the spot on the camera became smaller.
 
- SRM debiasing
 
First of all, the bias of the SRM was moved to zero.
Then the tower was rotated so that the beam is aligned in yaw.
After fine alignment of the SRM, the yaw slider was changed from -5.8 to 1.2.
The OSEMs on the SRM suspension was also checked. The OSEM insertions were
adjusted so that they show the half values of the open calibration
(the values can be found on the 40m wiki)
 
- Oplev check
 
SRM / ITMY / BS / PRM oplev paths in the chamber were checked.
The beams were aligned on the steering mirrors and the QPDs on the optical table.
The ITMX oplev was also checked from the windows without removing the door.
The beam is actually hitting the right positions of the steering mirror and the test mass
although there are lots of stray beams because of the BS oplev and some halo assciated with the ITMX He-Ne laser(!?).

- Checking the alignment
After we closed the light doors, we aligned the MC, the arms and the recycling mirrors.
Now the everything is aligned.
  10541   Thu Sep 25 19:42:12 2014 ericqUpdateGeneralVent progress

[q, Jenne, Manasa]

ELOG Outline

  • Aligned arms
  • Took a bunch of photos of ITMY chamber. 
  • Used Crystallaser to reverse trace POY beam path
  • Realized real POY flashes were visible
  • Tried adjusted POY steering to give us enough room to move SRM forward 3 in
  • Not enough steering room
  • Placed beam centering targets just before OM3 and after OM4, on far side of BS table
  • Twisted SR2 by ~5 degrees
  • Moved SRM laterally ~3 inches (beam had been hitting optic center, then suspension cage after SR2 twist)
  • Moved SRM foward about 3 inches, adjusted angle for coarse retroreflection
  • Measured distances between suspensions
  • Tried running Gabriele's distance reconstruction code, results not looking so good; redundancy checks are off by ~1cm
  • Started roughly repositioning OM1 and OM2 to get through beam targets
  • Closed light doors
  • ITMY pointing has gone bad, no green or IR resonance to be seen, still have IR and Green in Xarm, so TTs, BS are ok
  10544   Fri Sep 26 12:25:34 2014 ericqUpdateGeneralVent progress

I figured out that didn't change the initial guess for the fit routine in Gabriele's code. I also changed the fminsearch criteria to least squares fitting, instead of minimax. The consistency checks now look just as good as the previous time we did these kind of measurements, no disagreements bigger than 1.6mm. 

Thus, the current estimate of the SRC length after yesterday's motions is 5402mm, where we desire 5399mm. So, we will try to move SRM 3mm closer to SR2, after confirming that we are not clipping the POY beam. After all that, we will level the table.

  12243   Tue Jul 5 17:14:02 2016 ericqUpdateGeneralVent progress

Rough summary of today's progress:

  • IMC locked, reasonably aligned. (Only have MC2 trans reference, no WFS)
    • FSS Slow lock threshold got lowered to 1k MC2 trans
    • Autolocker doesn't really work, though I made some modifcations to it that reflect the manual locking that works
  • TTs, PRMI optics moved around until AS and REFL spots looked good. 
    • Small flashes visible in TRY
    • ND filter on Y transmon QPD removed, since we have so little light
  • Y arm was not locked, but this was deemed suitable to proceed
  • Heavy doors taken off ETMX and ITMX chambers, light doors put on.
  • Went into ETMX chamber, poked around, took a bunch of pictures (Gautam is uploading has uploaded to picasa (foteee account), the two best ones of the stand-offs on either side are attached, although I guess we can't really conclude anything from these except that on the side with the OSEM, there seems to be a few extra stray bits of epoxy residue...)
  • Removed ETMX side OSEM to get a picture of that side of optic (it is currently off, ETMX watchdog shutdown for now...)
  • Checked that table is level with clean spirit level (it was to within the resolution of the spirit level which is quoted as 0.42mm/m)

I didn't really see anything out of the ordinary on the ETMX suspension. Earthquake stops had clearance, OSEMS were secure, no visible glue degredation on face magnets. Inspection with green LED flashlight didn't reveal any obscene dirtieness on either face, just a few particles here and there. The top of the opic barrel unsurprisingly has a good amount of particulate. The wire grooves are way too small to resolve anything at this point, other than that they exist.

The suspension footprint is already marked, tomorrow we can move the suspension closer to the door to get an even closer look at it, before removing it from the chamber. 

Attachment 1: noOsemSide.JPG
noOsemSide.JPG
Attachment 2: OSEMside.JPG
OSEMside.JPG
  12245   Tue Jul 5 19:10:41 2016 ranaUpdateGeneralVent progress

I'd suggest clamping and moving it to the flow bench so you can inspect with a bright light. Then remove the wire and inspect the standoff, but hurry up with getting it in the soak bath so you can start on the cleaning of the other ones.

I wonder if we're really sure that its a mechanical problem with ETMX.

Gautam tells me that the local damping was always ON when looking for the jumps. This means that the coil driver was still hooked up and we can't rule out glitches in the DAC or the coil driver.

The UL OSEM shows the biggest movement (10 microns). The LR shows the second most (6-7 microns). The others are 2x less. So its consistent with a voltage change on UL,

Is this consistent with a slip in one of the wire standoffs? I think no.

 

Attachment 1: jumpEvent20151105.png
jumpEvent20151105.png
  12246   Tue Jul 5 21:51:35 2016 ericqUpdateGeneralVent progress

One glitch was seen to occur without a change in the output voltage monitors in ELOG 11744

  12270   Thu Jul 7 17:12:50 2016 JohannesUpdateGeneralVent progress

I performed a visual inspection of ITMY in its natural habitat today. I did not get any great pictures from the HR side because it's located very towards the edge of the table towards the arm. Before that I checked the levelness of the table. East-west direction was fine, north-south was slightly off but still within the marks for 'level'.

The AR side had several speckles, a few of them located somewhat near the geometrical center of ITMY. The top of the barrel was worse of, as expected. The HR side was a little better, but there were a few pieces of dust? near near the center. Sample pictures are attached, I uploaded all the good ones to Picasa.

Clamps that mark the position of ITMY were already in place. I did not move the optic just yet, and we will have to move a cable block out of the way to bring ITMY near the opening for us to work on it. We will markt the position of that to preserve the weight distribution. Then we can probably take some better before/after pictures. Tomorrow I will be looking at ETMY.

  12285   Sun Jul 10 17:33:00 2016 ericqUpdateGeneralVent progress

It took a little time, but I relocked the IMC and realigned to the point where the PRC is flashing, visible on REFL and AS, and tiny flashes are visible in TRY.

  14059   Thu Jul 12 16:18:22 2018 SteveUpdateVACVent preparations

We are getting ready to vent.

 

Attachment 1: before_Vent.png
before_Vent.png
Attachment 2: before_Vent_cond.png
before_Vent_cond.png
  8903   Tue Jul 23 04:31:36 2013 JenneUpdateGeneralVent preparation - Ready for Vent

After everyone's work today (good teamwork everybody!!), we are a GO for the vent.

Steve, please check the jam nuts, and begin the vent when you get in.  Thanks.

  8890   Mon Jul 22 16:56:14 2013 JenneUpdateGeneralVent preparation - In progress

Pre-vent checklist

  • Center all oplevs/IPPOS/IPANG
  • Align the arm cavities for IR and align Xgreen and Ygreen lasers to the arms.
    (X green+PSL green = TRX ~0.7 pre-swap and ~ 0.6 post-swap, Ygreen +PSL green TRY ~600 counts an hour or so after green was aligned to the arm.)
  • Make a record of the MC pointing
  • Align the beam at the PSL angle and position QPDs
     
  • Record good OSEM values.
     
  • Reduce input power by placing wave plate+PBS setup on the PSL table either BEFORE or AFTER THE PMC. (We will try attenuating the power using the WP + PBS that already exist after the laser. If this does not help attenuate enough, we will introduce WP+PBS after the PMC). Refer elog 6892 and elog 7299 for after the PMC detailed procedure.
     
  • Replace 10% BS before MC REFL PD with Y1 mirror and lock MC at low power.
  • Check the MC spot position measurement under the low power mode.
     
  • Close shutter of PSL-IR and green shutters at the ends
  • Make sure the jam nuts are protecting bellows
  8893   Mon Jul 22 18:49:16 2013 JenneUpdateGeneralVent preparation - In progress

I have just centered IPPOS, as well as PSL POS and PSL ANG (also called IOO POS and IOO ANG on the screens).  Annalisa is working on placing mirrors to get the IPANG beam to its QPD, so that one will be centered later.

  8894   Mon Jul 22 21:23:04 2013 manasaUpdateGeneralVent preparation - In progress

[Gautam, Manasa]

Green steering mirrors have been swapped with PZT mirrors at the X end table. We aligned the green to the X arm.

X arm green transmission +PSL green  ~ 0.95

That's better than before the swap...woohooo

  8898   Tue Jul 23 03:10:57 2013 KojiUpdateGeneralVent preparation - In progress

Centering of the oplev beams: done

Recording the OSEM values: done

Attachment 1: OSEM_RECORD.png
OSEM_RECORD.png
Attachment 2: OPLEVS.png
OPLEVS.png
  8899   Tue Jul 23 03:43:32 2013 manasaUpdateGeneralVent preparation - In progress

There seems to be an unexplained oscillation in X arm cavity transmission for IR when the cavity is locked using the POX error signal.

Their origin is not related to the oplevs because the oscillation does not exist when LSC is OFF and the arms are controlled only by the oplevs and OSEMs.

  8901   Tue Jul 23 04:22:03 2013 KojiUpdateGeneralVent preparation - In progress

[Koji Jenne]

Low power MC locking

- Rotated HWP right after the laser

- Put a knife edge beam dump at the output of the PBS after the HWP.

- Replaced the PO mirror for the MC refl by an HR mirror.

- PMC:
Input offset from 0 to 0.29
Servo Gain from 10 to 30
=> Transmission 0.84 (1.2W at the MC input) to 0.069 (100mW)

- MC:

VCO Gain from 25 to 31
MC REFL: Unlocked 3.6 Locked 0.38-0.40

  8889   Mon Jul 22 16:30:31 2013 KojiUpdateGeneralVent preparation

[Annalisa, Manasa, Jenne, Koji]

We are working on the vent preparation.

First of all, there was no light in the interferometer.
Obviously there were lots of IFO activity in the weekend. Some were elogged, some were not.
Annalisa took her responsibility to restore the alignment and the arms recovered their flashes.

The odd thing was that the ASS got instable after we turned down the TRY PD gain from +20dB to +10dB (0dB original).
We increased the TRY gain by factor of 10 (that's the "10dB" of this PDA520. See the spec sheet) to compensate this change.
This made the ASS instable. Anyway we reduced the gain of TRY PD to 0dB. This restored the ASS.

Jenne took some more data for the QPD spectrum calibration.

Link to the vent plan

  10528   Tue Sep 23 17:56:13 2014 Jenne, EricQUpdateGeneralVent prep for SRC length change

As Q mentioned in elog 10527, (prompted by Koji's email this afternoon) we are prepping the IFO for vent.  Here is a copy of the pre-vent checklist from the wiki, updated as we work:

 

Pre-vent checklists

 
  1. Center all oplevs/IPPOS/IPANG
  2. Align the arm cavities for IR and align the green lasers to the arms.
  3. Make a record of the MC pointing
  4. Align the beam at the PSL angle and position QPDs
  5. Reduce input power by adjusting wave plate+PBS setup on the PSL table BEFORE the PMC. (Using the WP + PBS that already exist after the laser.)
  6. Replace 10% BS before MC REFL PD with Y1 mirror and lock MC at low power.
  7. Close shutter of PSL-IR and green shutters at the ends
  8. Make sure the jam nuts are protecting bellows

Notes:

1 & 2:  Locked arms on IR, ran ASS.  Unlocked IFO, aligned PRM for good POP flashes, aligned SRM for symmetric AS flashes.  Aligned all oplevs.  Used PZTs to align Xgreen to arm. Used knobs to align Ygreen to arm.  With PS:L green shutter closed, Xgreen  = 0.520, Ygreen = 0.680.

3:  Moved MC servo output cable that goes to ADC from OUT2 (which we had been using for monitoring AO path signals) back to its usual OUT1 (which is MC_L).  This is used in the spot position measurement script.  Spots at:  [2.32, -0.50, 1.97, -1.11, 0.26, -1.86] mm.

4: Done -Q

5:  Removed a PD that was monitoring the light coming backwards through the Faraday that sits just after the laser, just in case (confirmed that beam dump behind PD was catching beam).  Other port of PBS just had regular black hole dump.  Adjusted half wave plate until we had ~90mW just before injection into the vacuum.

6: Completed. Locked MC manually at transmission of ~1150, but low power autolocker isn't working. This isn't a critical thing, and can be fixed at any point during the vent. -Q

7: Shutters closed. Ready for Steve to check nuts and begin venting! -Q

  10529   Wed Sep 24 08:39:32 2014 Jenne, EricQUpdateGeneralVent prep for SRC length change

Quote:

As Q mentioned in elog 10527, (prompted by Koji's email this afternoon) we are prepping the IFO for vent.  Here is a copy of the pre-vent checklist from the wiki, updated as we work:

 

Pre-vent checklists

 
  1. Center all oplevs/IPPOS/IPANG
  2. Align the arm cavities for IR and align the green lasers to the arms.
  3. Make a record of the MC pointing
  4. Align the beam at the PSL angle and position QPDs
  5. Reduce input power by adjusting wave plate+PBS setup on the PSL table BEFORE the PMC. (Using the WP + PBS that already exist after the laser.)
  6. Replace 10% BS before MC REFL PD with Y1 mirror and lock MC at low power.
  7. Close shutter of PSL-IR and green shutters at the ends
  8. Make sure the jam nuts are protecting bellows

Notes:

1 & 2:  Locked arms on IR, ran ASS.  Unlocked IFO, aligned PRM for good POP flashes, aligned SRM for symmetric AS flashes.  Aligned all oplevs.  Used PZTs to align Xgreen to arm. Used knobs to align Ygreen to arm.  With PS:L green shutter closed, Xgreen  = 0.520, Ygreen = 0.680.

3:  Moved MC servo output cable that goes to ADC from OUT2 (which we had been using for monitoring AO path signals) back to its usual OUT1 (which is MC_L).  This is used in the spot position measurement script.  Spots at:  [2.32, -0.50, 1.97, -1.11, 0.26, -1.86] mm.

4: Done -Q

5:  Removed a PD that was monitoring the light coming backwards through the Faraday that sits just after the laser, just in case (confirmed that beam dump behind PD was catching beam).  Other port of PBS just had regular black hole dump.  Adjusted half wave plate until we had ~90mW just before injection into the vacuum.

6: Completed. Locked MC manually at transmission of ~1150, but low power autolocker isn't working. This isn't a critical thing, and can be fixed at any point during the vent. -Q

7: Shutters closed. Ready for Steve to check nuts and begin venting! -Q

 

  14303   Sun Nov 18 00:59:33 2018 gautamUpdateGeneralVent prep

I've begun prepping the IFO for the vent, and completed most of the IFO related items on the checklist. The power into the MC has been cut, but the low-power autolocker has not been checked. I will finish up tomorrow and post the go ahead. PSL shutter is closed for tonight.

  14304   Sun Nov 18 17:09:02 2018 gautamUpdateGeneralVent prep

Vent prep

Following the checklist, I did these:

  • Both arms were locked to IR, TRY and TRX maximized using ASS.
  • GTRY and GTRX were also maximized.
  • ITM/ETM Oplevs centered with TRX/TRY maximized, PRM/SRM/BS Opelvs were centered once the DRMI was locked and aligned.
  • Attachment #1 summarizes the above 3 bullets.
  • Sensoray was made to work with Donatella (Raspberry Pi video server idea is good but although the sensoray drivers look to have installed correctly, when the Sensoray unit is plugged into the RPi USB port, the red light doesn't come on, so I opted to not spend too much time on it for the moment).
  • Photos of all ports in various locked configurations are saved in /users/sensoray/SensorayCaptures/Nov2018Vent
  • PSL power into the IMC was cut from 1.07 W (measured after G&H mirror) to 97 mW. I opted to install a new HWP+PBS after the PMC to cut the power, so we don't have to fiddle around so much with the PMC locking settings [Attachment #3, this was the only real candidate location as the IMC wants s-polarized light].
  • 2" R=10% BS in the IMC REFL path was replaced with a 2" Y1 HR mirror, so there is no MCREFL till we turn the power back up.
  • IMC was locked.
  • Low power MC autolocker works [Attachment #2]. The reduction in MCREFL is because of me manually aligning the cavity, WFS servos are disabled in low power mode since there is no light incident on the WFS heads.
  • Updated the SUS driftmon values (though I'm not really sure how useful this is).
  • PSL shutter will remain closed, but I have not yet installed a manual beam block in the beam path on the PSL table.

@Steve & Chub, we are ready to vent tomorrow (Monday Nov 19). 

Attachment 1: VentPrepNov2018.png
VentPrepNov2018.png
Attachment 2: MCautolocker_lowPower.png
MCautolocker_lowPower.png
Attachment 3: IMG_7163.JPG
IMG_7163.JPG
  14606   Mon May 13 18:48:32 2019 gautamUpdateGeneralVent prep
  1. c1auxey and c1aux VME crates were keyed.
  2. EX and EY NPROs were turned on.
  3. Y arm was aligned to the IR - best effort TRY ~0.75.
  4. EY green was aligned to the Y arm cavity. The spot is on the lower right quadrant on the CCD monitor, but GTRY ~0.35.
  5. #3 and #4 were repeated for XARM.
  6. All beams were centerd on Oplev and IP POS QPDs with this reference alignment - see Attachment #1. SOS Optic and TT DC bias positions were saved to burt snap files.
  7. I've never really used it but I updated all the SUS "driftmon" values - Attachment #2.
  8. Power going into the IMC was cut from 945 mW to 100 mW (both numbers measured with FieldMate power meter) by rotating the HWP installed last time for this purpose from 244 degrees (OLD) to 208 degrees (NEW). There was no beam dump for the reflected port of the PBS used to cut power, so I installed one, see Attachment #4.
  9. The T=90% BeamSplitter in the MC REFL path was replaced with a 2" HR mirror as is the norm for the low power IMC locking. Alignment of the MC REFL beam onto the MC REFL PD was tweaked.
  10. init.d file was edited and MCautolocker initctl process was restarted on Megatron to adopt the low power settings. It was locked, MCT ~1350 counts, see Attachment #3. Also adjusted the threshold level above which to have the slow PID offloading of FSS PZT voltage from 10000 to 1000.

I believe this completes the non-Chub portions of the pre-vent checklist, we will start letting air into the main volume ASAP tomorrow morning after crossing off the remaining items.

Main goal of this vent is to investigate the oddness of the YARM suspensions. I leave the PSL NPRO on overnight in the interest of data gathering, it's been running ~10 hrs now - I suspect it'll turn itself off before we are ready to vent in the AM.

Attachment 1: ventPrep_20190514.png
ventPrep_20190514.png
Attachment 2: driftMon_20190514.png
driftMon_20190514.png
Attachment 3: lowPowIMC.png
lowPowIMC.png
Attachment 4: IMG_7434.JPG
IMG_7434.JPG
  7842   Mon Dec 17 20:22:07 2012 JamieUpdateGeneralVent plan: WE VENT TOMORROW

We will vent tomorrow (12/18)

After lengthy discussion, I have determined that we should vent now, with the primary goal of this vent to replace the input steering PZTs with the new active tip-tilts.  Since we still don't understand exactly what's going on with the PRC, it's unclear what we would do to attack the problem.  We need to do more modeling and measurements first.  We should limit the goal of this vent to replacing the PZTs, and then close up and do more measurements with better modeling and improved input point in hand.

There is limited time this week before everyone leaves for two-week holidays on Thursday or Friday.  The reason to not vent would be that we don't want to leave the IFO at air during the two week holiday.  People seem to think that this is not a problem, so we don't gain anything by waiting.  Therefore we vent now and do what we can before people take off.

The goal for this week is to replace PZT1 only:

Now: Jenne and Manasa are doing vent prep.  Manasa is lowering the input power and preparing the mode cleaner.  Jenne centered IPPOS and IPANG.  This will allow us to check how the input alignment changed during the vent.

12/18: Steve is going to start the vent as soon as he gets back from the dentist, at around 10am.  He will regulate the vent such that we are ready to lock the mode cleaner by 4pm.  At that time we will lock the MC and recheck the input alignment with IPPOS/ANG, with the idea being to see if anything moves during the vent.

12/19: First thing in the morning we take off the access connector ONLY.  The access connector is all we'll need to replace PZT1.    Put light door on the OMC chamber side immediately, since we won't need to get in there at all.  We won't need the light access connector.

For the rest of Wednesday we'll remove PZT1 and install the new active TT.  We'll be using the current out-of-vac cable for PZT1 for the new TT.  We should only have to modify the rack end of the cable to accommodate the coil driver.  This should be a small modification.  Given that we have no wiring diagrams we'll have to pin it out in situ.

12/20: Hopefully finish up TT installation.

Jenne leaves 12/20, Manasa and Jamie leave 12/21.  We will either leave light doors on access connector holes, or possibly Rana, Koji, and Steve will replace access connector on Friday so that we can pump down to 1 Torr or something so that we leave it there over the holiday.

After we return from vacation:

PZT2/TT2 installation.  This will be less straight forward since the new TT has a bigger foot print than PZT2 and will block the PRM optical levers.  We'll need one additional steering mirror to redirect the oplev around the TT.  See elog 7815.

Once the new TTs are installed, we'll reevaluate where we're at.  If PRC modeling has progressed and we have an idea of something to work on with the PRC, we can.  Otherwise, we'll just button up, pump down, and get on with some better PRC measurements.

  7843   Mon Dec 17 21:33:45 2012 ManasaUpdateGeneralVent plan: WE VENT TOMORROW

Quote:

Manasa is lowering the input power and preparing the mode cleaner.

I aligned the PSL angle and position QPDs...then attenuated the input laser power using HWP-PBS-HWP combo from 1.28W to 100mW following instructions from elog 6892 and elog 7299.

To enable MC locking, I replaced the 10% BS before the MC_REFL PD with Y1 mirror. I tweaked the steering mirrors at the PSL table a teeny tiny bit to enable MC locking. MC is now locked at low power with 1.0 transmission.

  7848   Tue Dec 18 07:03:40 2012 ManasaUpdateGeneralVent plan: WE VENT TOMORROW

Quote:

 

12/19: First thing in the morning we take off the access connector ONLY.  The access connector is all we'll need to replace PZT1.    Put light door on the OMC chamber side immediately, since we won't need to get in there at all.  We won't need the light access connector.

 The access connector is all we'll need to replace PZT1.

Really? Can you be sure of the input pointing this way?

 

 

 

 

 

 

  14061   Thu Jul 12 23:59:14 2018 gautamUpdateGeneralVent objectives and prep

Vent objectives:

  1. Install radiative heater setup in EY chamber.
  2. Re-direct 50% of AS beam to OMC
    • First, we need to check if the OMC trans PDs work. Else, we have to consider using some in-air PDs for the transmon.
    • Check that OMC length PZT works.
    • Check that OMC steering PZTs work (Koji and I have used this in 2016 to check AS beam clipping so they should work).

We only anticipate opening up the IOO chamber and the EY chamber.


Vent preparation: see here.

  14063   Fri Jul 13 02:52:11 2018 gautamUpdateGeneralVent objectives and prep

[KA, GV]

  1. Arm scan setup moved from West side of PSL table to North side of AP table
    • Marconi is now providing the LO for the loop. A ~5m 50ohm BNC cable needs to be laid out from the PLL area to the NW corner of the AP table where the Agilent is for the TF measurement scheme which allows phase discrimination.
    • We took this opportunity to characterize/improve the setup a bit, and also clean up the 10s of cables around the PSL table. There were some Video cables (75ohm instead of 50ohm no) that were part of the scanning setup which we excised.
    • Mode matching onto beat PD on PSL table was improved - beat signal Vpp increased by factor of 2. PLL gain was adjusted accordingly. 
    • AUX power @AP table ~37mW (before recombination BS), ~3.7mW onto SRM, ~200uW onto ITMY.
    • We got a beatnote in transmission of ~120uV (rms?) after optimizing alignment into Y arm cavity with the AUX frequency on an arm FSR.
    • From Sandrine's calculations, I expected ~20mV of beat signal. We leave it to Annalisa and Terra to square that circle. Probably the MM into the arm isn't stellar either, and we didn't check the polarization of the aux beam (that it is matched to the IFO's p-pol).
    • The entire AUX injection chain needs careful characterization before
  2. Vent prep
    • Both arms were locked to IR, TRY maximized using ASS, TRX maximized by hand.
    • GTRY and GTRX were also maximized.
    • All test mass/PRM/SRM oplevs were centered with this "good" alignment.
    • PSL power into the IMC was cut from 1.07 W (measured after G&H mirror) to 97 mW, by rotating the waveplate immediately after the PSL (original angle 180deg, new angle 216 degrees).
    • PMC was locked. I did not need to change any of the gain settings.
    • 2" R=10% BS in the IMC REFL path was replaced with a Y2, so there is no MCREFL till we turn the power back up.
    • IMC was locked. I touched up my IMC low power autolocker, but this probably needs a bit more touching up tomorrow. MC has remained locked at low power for ~25mins, but as I typed this, I jinxed it and it lost the lock. anyway we have good alignment references.
    • PSL shutter will remain closed.

@SV, we are ready to vent tomorrow. Aaron is supposed to show up ~830am to assist.

Attachment 1: preVentStatus.png
preVentStatus.png
  14067   Fri Jul 13 17:13:45 2018 KojiUpdateGeneralVent objectives and prep

Notice: I removed these 75Ohm video cables.

Attachment 1: P_20180713_020603.jpg
P_20180713_020603.jpg
  34   Wed Oct 31 08:33:54 2007 ranaProblem FixedSUSVent measurements
There was a power outage during the day yesterday; whoever was around should post something here about the
exact times. Andrey and David and Tobin got the computers back up - there were some hiccups which you can
read about in David's forthcoming elog entry.

We restarted a few of the locking scripts on op340m: FSSSlowServo, MCautolocker. Along with the updates
to the cold restart procedures we have to put an entry in there for op340m and a list of what scripts
to restart.

David tuned up the FSS Slow PID parameters a little; he and Andrey will log some entry about the proper
PID recipe very soon. We tested the new settings and the step response looks good.

We got the MC locking with no fuss. The 5.6 EQ in San Francisco tripped all of the watchdogs and I upped
the trip levels to keep them OK. We should hound Rob relentlessly to put the watchdog rampdown.pl into
the crontab for op340m.
  8904   Tue Jul 23 08:21:31 2013 SteveUpdateVACVent has started

 

Thanks for the good preparation.  IFO pressure P1=20 Torr

Attachment 1: beforVent.png
beforVent.png
Attachment 2: startVent.png
startVent.png
  10530   Wed Sep 24 08:40:29 2014 SteveUpdateVACVent has started

 

 Jam nuts checked. Oplev servos turned off. Particle count checked. Vertex crane functionality checked.

Attachment 1: vent77.png
vent77.png
Attachment 2: bvent77.png
bvent77.png
  7307   Wed Aug 29 12:46:49 2012 SteveUpdateVACVent completed in 4 hrs

 

ANTS ALERT please watch out for ants. We have them in the control room.

 

 

Attachment 1: vent72.png
vent72.png
Attachment 2: beforeVentOpl.png
beforeVentOpl.png
Attachment 3: beforeVent.png
beforeVent.png
  15652   Thu Oct 29 19:30:56 2020 gautamUpdateGeneralVent complete
  1. Jam nuts - checked that none of the nuts move by hand, which according to Steve, is sufficient. I recorded photos of all of them here.
  2. Lab particle count - at the SP table, I measured 25,910 / cf @ 0.3 um and 1220 /cf  @ 0.5 um. Steve's guidance is that the latter number should be less than 10,000, so no issues there.
  3. Valves - closed all the annuli off, and also closed VM1, VA6 and V1. The procedure calls for VM3 to be opened, presumably so that the RGA remains pumped, but I see no reason why we can't just leave that RGA volume valved off.
  4. Started letting N2 into the main volume at ~3pm local time, by opening VV1. Attachment #1 shows the valve configuration adopted for this vent. Went up to 25 torr and then switched over to the "Ultra Zero" instrument grade air cylinders.
  5. Aimed for 3-5 torr/min rate of pressure increase locally. The full vent trend can be seen in Attachment #2.
  6. Stopped letting air into the main volume when P1a pressure was 700 torr, at which point I disconnected the cylinders from the main volume, and left VV1 open so that the IFO equilibriates to the lab air pressure. I used 4 full cylinders of the instrument grade air, which is par for the course. 
  7. Since we anticipate opening the ETMY and output optics chambers, I also vented those annuli. The final state of the valves as I am leaving it for the night is shown in Attachment #3.
  8. I re-aligned the IMC mirrors so that I could lock the IMC at low power once again. Indeed, IMC trans of ~1400 cts was realized (see Attachment #4), c.f. ~1500 earlier today, I thought this is fine and didn't optimize further. I think the policy is to not lock the IMC in air unless necessary, so I'm leaving the PSL shutter closed for the night.
  9. The ITMs, ETMs and BS were re-aligned such that the Oplev spots are centered. I can see some higher order resonances of the green beams. The AS spot is fringing (the two ND=0.5 filters on the AS CCD camera were removed for better visibility). So this is fine as far as alignment is concerned.

We are now ready to take the doors off. I've already done the basic prep work (loosened bolts, cleaned chamber, carts for tools, fresh ameristat on portable HEPAs etc).

Quote:

If everything else looks good, I'll start letting the dry N2 into the main volume after lunch.

Attachment 1: ventValveStatus.png
ventValveStatus.png
Attachment 2: vent_Oct2020.jpg
vent_Oct2020.jpg
Attachment 3: ventValveStatus_overnight.png
ventValveStatus_overnight.png
Attachment 4: lowPowerIMC_afterVent.png
lowPowerIMC_afterVent.png
  3264   Thu Jul 22 03:08:27 2010 KojiUpdateIOOVent and MC lock

Summary

- The vacuum chambers have been vented.

- The north heavy door of the BS chamber has been opened by Genie (not by the crane).
It was replaced by the light door. The door is currently closed.

- The MC has been locked with 20mW incident and aligned. MC REFL was left unchanged but lock was able to be achieved.

- The optics before MCT CCD and MCT QPD have been adjusted for the low power operation.


Details

- The first HWP for the variable optical attanuator (HWP/PBS/HWP pair) was set to be 86deg from the maximum transmission at 126deg.
The incident power of 19mW has been measured.

- The PSL mechanical shutter has been manually opened. Two other beam blocks has been removed.

- I found the MC was totaly misaligned with no resonance.- I tried to align it based on the previous OSEM values but in vain.

How to align the MC mirrors from the scratch

- MC1 has been aligned so as to maximize REFL PD and DC signal of WFS QPDs.

- MC3 has been aligned by looking at the scattered light on the MC2 frames. The spot is centered on the MC2 approximately.

- MC2 has been aligned so that any resonance is seen in MC_F.

Modification of the MCT optics

- The ND filter before the MCT was removed.

- The Y1-45S mirror before the MCT CCD, which is also used to steer the beam to the MCT QPD path, was replaced to BS1-50-45P.
The reason I used 45P is to obtain higher reflectivity. Because S has higher reflectivity than P in the each layer, I expected to have higher reflectivity for S than 50%.

- The MC REFL path has not been untouched.

Modification of the servo

- The lock was attempted after alignment of the mirrors.  Here how to lock the MC is described below.

1. Run script/MC/mcloopson

2. Open the MC Servo screen in MEDM

3. Change the input gain from 6dB to 22dB.
Change offset from 0.78 to -0.464 (such that the length output has no offset).
Change VCO Gain from 3dB to 21dB

Change MC Length path Gain from 0.3 to 1.6

  15658   Wed Nov 4 00:10:43 2020 gautamUpdateGeneralVent activities today

[koji, gautam]

  1. Glued broken off magnet - curing overnight with lamp to slightly elevate temp for curing.
  2. Remvoed material from OMC chamber as per the plan. This is all sitting wrapped up in foil on a cart for tonight, we should figure out a better storage plan eventually.

The IMC isn't resonant for a TEM00 mode at the time of writing - we are waiting for the stack to relax, at which point if the IMC isn't resonant for a TEM00 mode, we will tweak the input pointing into the IMC (we want to use the suspended cavity as the reference, since it is presumably more reliable than the table from which we removed ~50 kgs of weight and shifted the balance.

Attachment 1: IMG_0184.jpg
IMG_0184.jpg
Attachment 2: IMG_0185.jpg
IMG_0185.jpg
Attachment 3: IMG_0187.jpg
IMG_0187.jpg
Attachment 4: IMG_0207.jpeg
IMG_0207.jpeg
Attachment 5: IMG_0210.jpg
IMG_0210.jpg
  15660   Thu Nov 5 22:27:34 2020 gautamUpdateGeneralVent activities today

[koji, gautam]

  1. Tweaked last steering mirror before PSL beam is launched into vacuum to get the IMC resonant for the TEM00 mode. Less than 1/8 turn in each Pitch and Yaw was required, and we recovered MC2T ~ 1300 cts (c.f. the expected ~1500 cts when the cavity is well aligned, but we didn't touch the IMC mirrors).
  2. ETMY magnet re-gluing
    • Regluing was successful. Pickle picker came off smoothly. 
    • We performed the razor blade test on all 6 magnets, the integrity of the joints seems uncompromised.
  3. ETMY cleaning
    • Applied F.C. to HR face, HR edge (to remove some residual stains) and AR surface (taking care to go around the magnets).
    • A fresh bottle each of spectroscopic grade acetone and isopropanol was dispensed into clean beakers for the work.
    • Curiously, in the lighting conditions of the cleanroom, both HR and AR faces looked surprisingly clean, even when illuminated with the green flashlight.
    • However, when we took it to the east end and looked at it again with the green flashlight, just before putting it into the chamber, we saw all sorts of stains and markings on the HR side.
    • The central aperture looks fine - the contamination did not happen during the transport so we feel confident not to futz around more with this and since we cleaned it extensively in the cleanroom, we opted not to do another round of cleaning in the chamber.
  4. ETMY re-suspension (on the existing wire loop)
    • The back OSEM-holding plates were removed for access reasons.
    • The optic was rested onto the EQ stops. 
    • Patient nudging of the wire around the optic allowed us to eventually get the wire into the V-grooves in the standoffs.
    • The wire was not damaged! (at least, to eye, free-swinging test is going on now, we will see what the eigenfrequencies and Qs are)...
    • We confirmed that the wire is seated in the v-groove, and took some close up photos.
  5. ETMY pitch balancing
    • A HeNe was brought into the cleanroom and mounted at 5.5" beam height.
    • Level-ness of the beam (i.e. parallel to the optic table) was done coarsely with a spirit level placed on the HeNe holder, and more fine adjustment was done by checking the beam height at the launch point, and again ~2 meters away.
    • All EQ stops were backed off to ensure the optic was really "free-swinging" - no OSEMs either at this point, since all this was done in the cleanroom.
    • The return beam hit the HeNe's output aperture, so we were satisfied that the pitch balancing was good to ~1mrad.
  6. ETMY transport back to EY
    • Since we want to maintain some tension in the wires, the bottom EQ stops were not raised as much as they were when the tower was transported from EY to the cleanroom.
    • As a result, we felt it'd be better for a human (Koji) to carry the cage (rather than cart it, the idea being that there would be fewer vertical impulses due to bumps on the ground etc).
    • The transport went smooth.
  7. EY chamber work
    • Optic was placed back in its original position (marked by some L-clamps).
    • In preparation for alignment work, I undid all the CDS changes I made to facilitate the temporary 3-magnet actuation. This necessitated a reboot of c1auxey VME crate.
    • OSEMs were inserted - best effort to half light as usual, and we tried to replicate the rotation in the mounts as closely as possible to what was the case before (using a photo from the last vent as reference).
    • Coarse alignment was done by making the Oplev return beam hit the QPD.
    • Better alignment of the Y-arm cavity axis was done using the green beam. 
    • IMC was locked - the beam alignment target was used to ensure the IR beam was hitting ETMY at the correct height (by moving TT2), and then the ETMY angular alignment was improved to make the return beam go back roughly collinearly.
  8. Y-arm POY locking
    • Satisfied with the alignment, we returned to the control room (light doors back on EY chamber) - cavity alignment was tweaked further to make the TRY resonances as high as possible.
    • I could lock the Y-arm length to the PSL frequency using POY as a sensor - TRY was ~0.04-0.05 (since IMCT is 1/10th its usual value, we expect it to be 0.1, so this is not bad).
  9. OMC chamber work
    • Tied down the balance weights that were previously placed after the OMC and peripheral optics were removed.
    • Checked the table leveling.
    • Checked that the AS beam is reasonably well centerd on OM5 and OM6. Took some photos.
    • Checked that the IMC could be locked after this work - it could.

So all the primary vent objectives have been achieved 🙌 . The light doors are on the chamber right now. I'm measuring the free-swinging spectra of ETMY overnight. Barring any catastrophic failures and provided all required personnel are available, we will do the final pre-close-up checks, put the heavy doors back on, and pump down starting 10 am Monday, 9 Nov 2020. Some photos here.

  15664   Sun Nov 8 20:22:35 2020 gautamUpdateGeneralVent activities today

Basic IFO alignment checks were done.

  1. IMC could be locked - I tweaked the cavity alignment a little to maximize the MC transmission.
  2. Y arm can be made resonant for a TEM00 mode of the main beam. I can't run ASS successfully in this low power config. I can see that the axis isn't great, the spot is visually off-center on ITMY, but we should have plenty of actuator range to correct for this with TT1/TT2.
  3. X arm shows IR mode flashes in the TRX QPD. The green beam can be made resonant for a TEM00 mode, but that alignment doesn't yield the largest IR resonant peaks in TRX. I suspect it is due to the mis-alignment of the beam axis.
  4. AS beam was aligned onto the CCD. I could see clean Michelson fringes by tweaking the BS alignment. On the AP table, I noticed that the beam on the first steering mirror after the AS beam exits the vacuum is a little high. We can easily resolve this by tweaking OM6 pitch a bit, but even if we don't I don't see any major issues as there is plenty of clearance w.r.t. the viewport when the beam exits the vacuum.
  5. With the PRM aligned, I can see the REFL beam on the CCD, and it doesn't look clipped.
  6. I didn't bother to align the green beams to the arm cavities or re-center the Oplevs - is this necessary? It is a step in the pre-close up checklist, so maybe we should do it... The green transmission does reach the PSL table...

Tomorrow, we should do some visual checks of the chambers / EQ stops on ETMY etc but I don't see any major problems at the moment...

Quote:
 

Barring any catastrophic failures and provided all required personnel are available, we will do the final pre-close-up checks, put the heavy doors back on, and pump down starting 10 am Monday, 9 Nov 2020.

Attachment 1: IFOalignment.png
IFOalignment.png
  15665   Sun Nov 8 23:24:29 2020 KojiUpdateGeneralVent activities today

> I didn't bother to align the green beams to the arm cavities or re-center the Oplevs - is this necessary? It is a step in the pre-close up checklist, so maybe we should do it... The green transmission does reach the PSL table...

I don't think so. The beam is reaching the PSL, so we have no motivation to change the green alignment. Regarding the oplev, the green refl should come back to the PDH PD and this gives us additional beam reference. As soon as we find the green resonance after the pumping, we can tweak the green axis so that the spots on the mirrors become reasonable (as well as the green trans CCD on the PSL table).

 

  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?

Attachment 1: Screen_Shot_2021-10-18_at_14.52.34.png
Screen_Shot_2021-10-18_at_14.52.34.png
Attachment 2: Screenshot_2021-10-18_15-08-59.png
Screenshot_2021-10-18_15-08-59.png
  16412   Tue Oct 19 10:59:09 2021 KojiUpdateVACVent Started / Completed

[Chub, Jordan, Yehonathan, Anchal, Koji]

North door of the BS chamber opened

 

ELOG V3.1.3-