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  14306   Mon Nov 19 17:09:00 2018 SteveUpdateVACVent 81

Gautam, Aaron, Chub and Steve,

Quote:

Vent 80 is nearly complete; the instrument is almost to atmosphere.  All four ion pump gate valves have been disconnected, though the position sensors are still connected,and all annulus valves are open.  The controllers of TP1 and TP3 have been disconnected from AC power. VC1 and VC2 have been disconnected and must remained closed. Currently, the RGA is being vented through the needle valve and the RGA had been shut off at the beginning of the vent preparations.  VM1 and VM3 could not be actuated.  The condition status is still listed as Unidentified because of the disconnected valves. 

The vent 81 is completed.

4 ion pumps and cryo pump are at ~ 1-4 Torr (estimated as we have no gauges there), all other parts of the vacuum envelope are at atm. P2 & P3 gauges are out of order.

V1 and VM1 are in a locked state. We suspect this is because of some interlock logic.

TP1 and TP3 controllers are turned off.

Valve conditions as  shown: ready to be opened or closed or moved or rewired. To re-iterate: VC1, VC2, and the Ion Pump valves shouldn't be re-connected during the vac upgrade.

Thanks for all of your help.

Attachment 1: beforeVent82.png
beforeVent82.png
Attachment 2: vent81completed.png
vent81completed.png
  14318   Mon Nov 26 15:58:48 2018 SteveUpdateVACVent 81

Gautam, Aaron, Chub & Steve,

ETMY heavy door replaced by light one.

We did the following:  measured 950 particles/cf min of 0.5 micron at SP table, wiped crane and it's cable, wiped chamber,

                                placed heavy door on clean merostate covered stand, dry wiped o-rings and isopropanol wiped Aluminum light cover

                              

Quote:

Gautam, Aaron, Chub and Steve,

Quote:

Vent 80 is nearly complete; the instrument is almost to atmosphere.  All four ion pump gate valves have been disconnected, though the position sensors are still connected,and all annulus valves are open.  The controllers of TP1 and TP3 have been disconnected from AC power. VC1 and VC2 have been disconnected and must remained closed. Currently, the RGA is being vented through the needle valve and the RGA had been shut off at the beginning of the vent preparations.  VM1 and VM3 could not be actuated.  The condition status is still listed as Unidentified because of the disconnected valves. 

The vent 81 is completed.

4 ion pumps and cryo pump are at ~ 1-4 Torr (estimated as we have no gauges there), all other parts of the vacuum envelope are at atm. P2 & P3 gauges are out of order.

V1 and VM1 are in a locked state. We suspect this is because of some interlock logic.

TP1 and TP3 controllers are turned off.

Valve conditions as  shown: ready to be opened or closed or moved or rewired. To re-iterate: VC1, VC2, and the Ion Pump valves shouldn't be re-connected during the vac upgrade.

Thanks for all of your help.

 

  14398   Mon Jan 14 10:06:53 2019 gautamUpdateVACVent 82 complete

[chub, gautam]

  • IFO pressure was ~2e-4 torr when we started, on account of the interlock code closing all valves because the N2 line pressure dropped below threshold (<65 psi)
  • Chub fixed the problem on the regulator in the drill-press area where the N2 tanks are, the N2 line is now at ~75 psi so that we have the ability to actuate valves if we so desire
  • We decided that there is no need to vent the pumpspool this time - avoiding an unnecessary turbo landing, so the pumpspool is completely valved off from the main volume and TPs 1-3 are left running
  • Went through the pre-vent checklist:
    • Chub measured particle count, deemed it to be okay (I think we should re-locate the particle counter to near 1X8 because that is where the air enters the IFO anyways, and that way, we can hook it up to the serial device server and have a computerized record of this number as we had in the past, instead of writing it down in a notebook)
    • Checked that the PSL was manually blocked from entering the IFO
    • Walked through the lab, visually inspected Jam Nuts and window covers, all was deemed okay
  • Moved 2 tanks of N2 into the lab on account of the rain
  • Started the vent at ~930am PST
    • There were a couple of short bursty increases in the pressure as we figured out the right valve settings but on average, things are rising at approx the same rate as we had in vent 81...
    • There was a rattling noise coming from the drypump that is the forepump for TP2 (Agilent) - turned out to be the plastic shell/casing on the drypump, moreover, the TP2 diagnostics (temperature, current etc) are all normal.
    • The CC1 gauge (Hornet) is supposed to have an auto-shutoff of its High Voltage when the pressure exceeds 10 mTorr, but it was reporting pressures in the 1 mTorr range even when the adjacent Pirani was at 25 torr. To avoid risk of damage, we manually turned the HV off. There needs to be a python script that can be executed to transition control between the remote and local control modes for the hornet, we had to Power Cycle the gauge because it wouldn't give us local control over the HV.
    • Transitioned from N2 to dry air at P1a=25 torr. We had some trouble finding the correct regulator (left-handed thread) for the dry air cylinders, it was stored in a cabinet labelled green optics no
    • Disconnected dry air from VV1 intake once P1b reached 700 torr, to let lab air flow into the IFO and avoid overpressuring.
    • VA* and VAV* valves were opened so as to vent the annuli as we anticipate multiple chamber openings for this vent.

As of 8pm local time, the IFO seems to have equilibriated to atmospheric pressure (I don't hear the hiss of in-rushing air near 1X8 and P1a reports 760 torr). The pumpspool looks healthy and there are no signs in the TP diagnostics channels that anything bad happened to the pumps. Chub is working on getting the N2 setup more robust, we plan to take the EY door off at 9am tomorrow morning with Bob's help.

* I took this opportunity to follow instructions on pg 29 of the manual and set the calibration for the SuperBee pirani gauge to 760 torr so that it is in better agreement with our existing P1a Pirani gauge. The correction was ~8% (820-->760).

Attachment 1: Vent82Summary.png
Vent82Summary.png
  12233   Thu Jun 30 16:11:57 2016 ericqUpdateGeneralVent Prep

I have updated the vent prep checklist on the wiki. Gautam and I did the following things from it:

  • Center all oplevs, transmon QPDs 
    • ETMX oplev has not been centered, since it's moving around so much, and we're going to immediately move the suspension anyways.
  • Align the arm cavities for IR and align the green lasers to the arms. 
    • AUX X Green was aligned while the X arm was well aligned. Soon thereafter, ETMX wandered away, but the green will remain a good reference
  • Update the SUS Dritmon values 
  • Reconcile all SDF differences 
  • Reduce input power to no more than 100mW by adjusting wave plate+PBS setup on the PSL table BEFORE the PMC. (Using the WP + PBS that already exist after the laser.) 

  • Replace 10% BS before MC REFL PD with Y1 mirror and lock MC at low power.
    • I don't think we've vented since the most recent slew of changes to the IMC servo, so its not surprising that the current low power scripts don't work. I'm working on locking the IMC, but this does not prevent us from initiating the vent tomorrow.

 

The following bullets have not yet been executed:

  • Close shutter of PSL-IR and green shutters at the ends 
  • Make sure the jam nuts are protecting bellows 
  • Check crane functionality & cleanliness 

  • Turn off HV into vacuum: OMC is not wired this time 
  • Particle count must be under 10,000 counts / cf min for 0.5 micron 
  • Check all metal window covers are on. 
  • Check 5 cylinders (24 cft size) of instrument grade air, called Alfa Gas 1 in stock.
  12235   Thu Jun 30 21:24:36 2016 ericqUpdateGeneralVent Prep

Steve has ordered some teflon parts to take the place of the metal parts in his acetone-soaking jig. They should arrive tomorrow. 

So, we will be begin the venting process tomorrow. Doors to come off on Tuesday.

  15649   Wed Oct 28 20:42:53 2020 KojiUpdateGeneralVent Prep
  1. Two arms / BS / PRM / SRM were aligned. (Attachment 1)
  2. IMC was aligned by WFS and the WFS offsets were offloaded.
  3. Suspension Status Snapshot (Attachment 2)
  4. Oplevs are aligned (Attachment 3)
  5. Xarm green was aligned in the daytime. Xarm green refl DC (C1:ALS-X_REFL_DC_OUTPUT) was 620 (aligned) ~1300 (drifted). When unlocked, it was 3750.
  6. Yarm green: I saw no flash. We don't have functional PZT alignment since the ASY M2 PZT got broken. I went to the Yend. Something funky is going on with the Yend green. I struggled to have any flash of the cavity. The apertures were not so precise. I finally got TEM00 locked, but the modematching seems exteremely low (like 1/1000?). Basically I saw no power reduction of the refl when the cavity is locked. So at least the cavity was locked but we might need to revisit when we open the chamber
    ==> Gautam thinks it was not like that. So he will check the green alignment tomorrow (Thu).
  7. Item checking: I familialized myself with the yend crane operation. Today I learned that there is a power switch on the wall (Attachment 4). The yend has two heavy door storages (Attachments 4/5). The slings to lift the heavy door are in the crane cabinet along with the y arm (Attachment 6). I didn't yet try to find the "hammer" to hit the door if the o-ring stuck too strong, although that's optional.
  8. We want to reduce the PSL power. But Gautam wants to use the arm locking with the nominal power, it will be done tomorrow by him.
     
  9. The last thing is to check the green trans power. I noticed that the green trans beams are blocked by an HWP for the BHD LO path on the PSL table. (Attachment 7)
    The HWP was moved and the process was recorded in the movie (Attachment 8). The fiber output was monitored by the BHD DC (aka AS110 DC) with the AS path blocked. The fiber output of 22.6mV (offset -2.5mV) was improved tio 29.1mV after the HWP move and the alignment adjustment.
  10. Now the green transmissions are visible by the green PDs. Attachment 9 shows the trans and ref of each green beams with and without locking to TEM00. The questionable green TRY was ~0.3. If we compare this with the histrical data (Attachment 10), it is about 1/4 of the value in the past. It's not too crazy but still quite low.

At this point, I'm leaving the lab. All the suspensions (incl SRM) are aligned. PSL/GRX/GRY shutters were left open.

Attachment 1: Screen_Shot_2020-10-28_at_19.42.27.png
Screen_Shot_2020-10-28_at_19.42.27.png
Attachment 2: Screen_Shot_2020-10-28_at_19.42.38.png
Screen_Shot_2020-10-28_at_19.42.38.png
Attachment 3: Screen_Shot_2020-10-28_at_20.42.26.png
Screen_Shot_2020-10-28_at_20.42.26.png
Attachment 4: P_20201028_222839.jpg
P_20201028_222839.jpg
Attachment 5: P_20201028_223020.jpg
P_20201028_223020.jpg
Attachment 6: P_20201028_223212.jpg
P_20201028_223212.jpg
Attachment 7: 2020-10-28-233038.jpeg
2020-10-28-233038.jpeg
Attachment 8: HWP_moving.mp4
Attachment 9: Screenshot_from_2020-10-29_01-04-06.png
Screenshot_from_2020-10-29_01-04-06.png
Attachment 10: Screenshot_from_2020-10-29_01-16-53.png
Screenshot_from_2020-10-29_01-16-53.png
  15651   Thu Oct 29 12:43:35 2020 gautamUpdateGeneralVent Prep
  1. Oplev HeNe at ETMY was replaced, see here for my earlier discussion on this.
    • I thought this is a good idea since we want the Oplev as a coarse reference and it'd not be ideal if this HeNe dies during the time the optic is out of the chamber.
    • New HeNe had 2.8mW of power output as measured with Ophir power meter. This is in line with what is expected from these Lumentum heads.
    • I labelled the head with the power output and today's date, re-aligned the Oplev reflection onto its QPD. 
    • After this work, the Y-arm could be locked without the huge angular fluctuations that was visible earlier, 👍 .
  2. GTRY anomaly
    • I actually judged that there is no anomaly.
    • The GTRY CDS indicator is actually quite useless - the ADC saturates at ~3500 cts (and not 32768 as you would expect from a 16 bit ADC but that's the well-known whitening filter saturation problem). This should be fixed, but this is a task for later.
    • I measured with a DMM the voltage when the TEM00 is locked to the cavity and GTRY is 0.3 (the nominal value these days), the DC voltage was ~5.6 V. The prompt reflection from the ETM registers ~6.5 V DC. So the mode-matching isn't stellar, but this is again a known issue, and can be fixed later.
  3. Other pre-vent checks
    • The Oplevs had drifted significantly, I re-centered ITMs, ETMs and BS after aligning the arm cavities and green beams in the POX/POY lock state. See Attachment #1.
    • I locked the PRMI on carrier and used this config to re-center the PRM Oplev, see Attachment #2.
    • No further action was taken regarding SRM oplev.
    • I checked the ALS noise, see Attachment #3. The X arm ALS has excess noise at ~100 Hz that certainly wasn't there previosuly - sigh. There is nothing I can find about any changes made at EX in the elog.
    • Updated the "DriftMon" values, though I guess we don't even really use this anymore these days?
    • Re-relieved the IMC WFS offsets.
    • Cut the input power to the IMC from 1.007W to 100.1 mW (both numbers measured with Ophir power meter).
    • Replaced the 10% beamsplitter in the MCREFL path on the AS table with a Y1 HR mirror. Note that there is no beam on the IMC WFS in this configuration.
    • Was able to lock the IMC on low power to a TEM00 mode - need to set up the low power autolocker. The IMC autolocker is now set to the low power settings, and I've tested it locks a couple of times. Attachment #5 shows the low power lock in StripTool.
    • Walked around and looked at all the bellows - the jam nuts are up against their stops, and I can't move them with my hands, so I think that's okay.

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

Quote:

Now the green transmissions are visible by the green PDs. Attachment 9 shows the trans and ref of each green beams with and without locking to TEM00. The questionable green TRY was ~0.3. If we compare this with the histrical data (Attachment 10), it is about 1/4 of the value in the past. It's not too crazy but still quite low.

BTW, nice video! @ Koji, How difficult was it to edit it into this form? 

Attachment 1: preVentAlignment.png
preVentAlignment.png
Attachment 2: PRMIcarr_PRMalignment.png
PRMIcarr_PRMalignment.png
Attachment 3: ALS_ool.pdf
ALS_ool.pdf
Attachment 4: lowPowerMC.png
lowPowerMC.png
  16407   Fri Oct 15 16:46:27 2021 AnchalSummaryOptical LeversVent Prep

I centered all the optical levers on ITMX, ITMY, ETMX, ETMY, and BS to a position where the single arm lock on both were best aligned. Unfortunately, we are seeing the TRX at 0.78 and TRY at 0.76 at the most aligned positions. It seems less power is getting out of PMC since last month. (Attachment 1).

Then, I tried to lock PRMI with carrier with no luck. But I was able to see flashing of up to 4000 counts in POP_DC. At this position, I centered the PRM optical lever too (Attachment 2).

Attachment 1: Screen_Shot_2021-10-15_at_4.34.45_PM.png
Screen_Shot_2021-10-15_at_4.34.45_PM.png
Attachment 2: Screen_Shot_2021-10-15_at_4.45.31_PM.png
Screen_Shot_2021-10-15_at_4.45.31_PM.png
Attachment 3: Screen_Shot_2021-10-15_at_4.34.45_PM.png
Screen_Shot_2021-10-15_at_4.34.45_PM.png
Attachment 4: Screen_Shot_2021-10-15_at_4.34.45_PM.png
Screen_Shot_2021-10-15_at_4.34.45_PM.png
  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
    -304.7661529521767
    -109.23924626857811
    scripts>z read C1:SUS-ITMX_PIT_BIAS C1:SUS-ITMX_YAW_BIAS
    15.534616817500943
    -503.4536332290159
    scripts>z read C1:SUS-ITMY_PIT_BIAS C1:SUS-ITMY_YAW_BIAS
    653.0100945988496
    -478.16260735781225
    scripts>z read C1:SUS-ETMX_PIT_BIAS C1:SUS-ETMX_YAW_BIAS
    -136.17863332517527
    181.09285307121306
    scripts>z read C1:SUS-ETMY_PIT_BIAS C1:SUS-ETMY_YAW_BIAS
    -196.6200333695437
    -85.40819256078339

     
  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.
    >z read C1:ALS-TRX_OUTPUT C1:ALS-TRY_OUTPUT
    0.42343354488901286
    0.24739624058377277

    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
    >z read C1:ALS-TRX_OUTPUT C1:ALS-TRY_OUTPUT
    0.41822833190834546
    0.025039383697636856
    >z read C1:ALS-TRX_OUTPUT C1:ALS-TRY_OUTPUT
    0.00021112720155274818
    0.2249448773499293

    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.
    CAUTION: IF THE POWER IS INCREASED TO THE NOMINAL WITH THIS CONFIGURATION, MC REFL PD WILL BE DESTROYED.
  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.
Attachment 1: Screenshot_2021-10-15_17-36-00.png
Screenshot_2021-10-15_17-36-00.png
Attachment 2: Screenshot_2021-10-15_17-39-58.png
Screenshot_2021-10-15_17-39-58.png
Attachment 3: Screenshot_2021-10-15_17-42-20.png
Screenshot_2021-10-15_17-42-20.png
Attachment 4: Screenshot_2021-10-15_17-46-13.png
Screenshot_2021-10-15_17-46-13.png
Attachment 5: Screenshot_2021-10-15_18-05-54.png
Screenshot_2021-10-15_18-05-54.png
Attachment 6: Screen_Shot_2021-10-15_at_19.45.05.png
Screen_Shot_2021-10-15_at_19.45.05.png
Attachment 7: Screen_Shot_2021-10-15_at_19.47.10.png
Screen_Shot_2021-10-15_at_19.47.10.png
  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

  12299   Wed Jul 13 15:35:56 2016 LydiaUpdateGeneralVent Progress - ETMY repositioned and removed

[Lydia, Johannes]

Took photos to document the original OSEM orientation and wrote down the serial numbers for each position. We removed the OSEMs, moved the suspension to the accessible side of the table and took out the optic, which was brought to the clean room to have the magnets reglued. The ETMY chamber is now closed up with the OSEMs and clamps inside on the table, and should not need to be reopened until the magnets have been reattached. 

  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

 

  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).

 

  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

  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
  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
  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
  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.
  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
  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?

 

 

 

 

 

 

  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
  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

 

  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

  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

  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.

  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
  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

ELOG V3.1.3-