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ID Date Author Type Category Subject
9566   Wed Jan 22 16:36:45 2014 ericqUpdateElectronicsRF distribution box power button fail

 Quote: Rana, Gabriele and I are trying to measure the FSR of the PRC (elog about that later), and we turned off the power to the RF generation box so that we could switch cables at the EOM combiner.  However, as in elog 9101, the power button won't latch when we try to turn the power back on.  All 3 of us tried, to no avail.  For our measurement, poor Gabriele is standing holding the button pushed in, so that we can have some RF sidebands.  Tomorrow, we'll have to pull the RF generation box, and put in a better switch.

I replaced the stupid broken fancy button with a simple sturdy switch. I had to file out the hole in the chassis a bit, but the switch is pressed in tightly and securely. I put the box back in the rack, but the power cable was coming directly from the power supplies with no fuses. The box was drawing ~.9 and 1.5 Amps from two supplies, so I put 2A fuses on both. Plugged everything back in, and the mode cleaner locks, so it looks like all is well.

RXA: When its so close, I prefer to size it up by 1 step. Please change to 5A fuses. Otherwise, we may blow them from power glitches.

Q: 5A fuses have been swapped in

9567   Wed Jan 22 18:17:46 2014 JenneUpdateCDSfb timing was off

Since this morning, the fb's timing has been off.  Steve pointed it out to me earlier today, but I didn't have a chance to look at it until now.

This was different from the more common problem of the mx stream needing to be restarted - that causes 3 red blocks per core, on all cores on a computer, but it doesn't have to be every computer.  This was only one red block per core in the CDS FE status screen, but it was on every core on every computer.

The error message, when you click into the details of a single core, was 0x4000.  I elog searched for that, and found elog 6920, which says that this is a timing issue with the frame builder.  Since Jamie had already set things on nodus' config correctly, all I did was reconnect the fb to the ntp:

`fb\$ sudo /etc/init.d/ntp-client restart `

As in elog 6920, the daqd stopped, then restarted itself, and cleared the error message. It looks like everything is good again.

I suspect (without proof) that this may have to do with the campus network being down this morning, so the computers couldn't sync up with the outside world.

9568   Wed Jan 22 20:00:41 2014 JenneUpdateGeneralVENT GO!

Steve, please begin the vent!!

[EricQ, Jenne]

We have followed the pre-vent checklist, and done everything except check the jam nuts (which Steve can do in the morning).

We are ready to vent, so Steve, please begin bringing us up to atmosphere first thing in the morning.

Here is a copy of the list, from the wiki:

• Center all oplevs/IPPOS/IPANG
• Align the arm cavities for IR and align the green lasers to the arms. (Green powers were both ~0.8.  We only touched the Xend PZTs remotely, did not touch Yend).
• Make a record of the MC pointing
• Align the beam at the PSL angle and position QPDs (Did not need doing, left QPDs as-is so we keep our long-term trend.)
• Reduce input power by touching wave plate on the PSL table BEFORE THE PMC.  (HWP was at 269degrees, now at 3 hundred something to make power just before PSL shutter 90mW)
• Replace 10% BS before MC REFL PD with Y1 mirror and lock MC at low power.
• Close shutter of PSL-IR and green shutters at the ends
• Make sure the jam nuts are protecting bellows
•

Attachment 1: IFOstatus_lowPower_preVent.png
9570   Thu Jan 23 08:04:04 2014 SteveUpdateVACvacuum control screen is blank

There is BLANK VacControl_BAK.adl screen only.

I can move a valve by disconnecting it's  solenoid power if it's position is normally open.

I will close V1 and check computer cable connections and move on with manual - hand disconnect ea valve to be moved into the right position for vent. Valve positions will be confirmed by looking manual indicators on valves.

Attachment 1: pd76m170d2dRgaOn.png
9571   Thu Jan 23 13:23:10 2014 SteveUpdateVAC40m IFO is at atmosphere

 Quote: There is BLANK VacControl_BAK.adl screen only.  I can move a valve by disconnecting it's  solenoid power if it's position is normally open. I will close V1 and check computer cable connections and move on with manual - hand disconnect ea valve to be moved into the right position for vent. Valve positions will be confirmed by looking manual indicators on valves.

The 40m vacuum envelope vent is completed with instrument grade air.

Valve configuration: chamber open, RGA is pumped through VM3 by TP3,

9572   Thu Jan 23 23:10:19 2014 ericq UpdateGeneralVent so far

[ericq, Manasa, Jenne]

Summary: We opened up the BS and both ITM chambers today, and put the light doors on. //Edit : Manasa  Post-vent the MC was very much misaligned in yaw. Both the ITMs moved in pitch as inferred from the oplev; but there is still light on the oplev PDs//. We toiled with the PMC and mode cleaner for a while to get reasonable transmission and stability (at least for a period of time). We then tried to lock IR to the y-arm, to no avail.

Locking the PMC doesn't seem very robust with the low power level we have; adjusting the gain at all when it's locked throws it right out. The mode cleaner spot was visibly moving around on MC2 as well. We'll continue tomorrow.

Details about alignment efforts: Manasa and I tried for a while to try and align the y-arm for IR. Straight out of venting the green TM00 would lock to the y-arm with about .45, as compared to .8 before venting, so it didn't seem to drift too far. The x-arm would even flash any modes, however. For a while, IR was no where to be seen after the mode cleaner. Eventually, we used the tip tilts to bring the AS beam onto the camera, which exhibited fringes, so we knew we were hitting the ITMs somewhere. We wandered around with the ETM to see if any retroflection was happening, and saw the IR beam scatter off of the earthquake stop. We moved it to the side to see it hitting the OSEM holder, and moved down to the bottom OSEM holder to get an idea of where to put pitch to get roughly the center of the ITM, then undid the yaw motion.

There, we would see very infrequent, weak flashes. We weren't able to distinguish the mode shape though; however, the flashes were coincident with where the green would lock to a very yaw-misaligned fishbone mode, to the lower right of the optic's center. We figured that if we gradually fixed the green alignment with the mode shapes we could see and actually lock on, we could use the tip tilts to adjust the IR pointing and keep it coincident and eventually resonate more. However, this didn't really work out. The flashes were very infrequent, and at this point the PMC/MC were getting very touchy, and would cease to stay locked for more than a minute or two. At this point, we stopped for the day.

9576   Mon Jan 27 09:08:00 2014 SteveUpdateVAC4 days at atmosphere

Attachment 1: day4atm.png
Attachment 2: vent76bgTp3d4.png
9577   Mon Jan 27 12:26:00 2014 KojiUpdateIOOIOO Slow Actuator Servo threshold changed

In order to activate the slow actuator servo for the MC locking,
the threshold level for this servo (C1:PSL-FSS_LOCKEDLEVEL) was changed from 10000 to 700.

Now the servo started to move the PZT fast out to be controlled to 5V.

9579   Mon Jan 27 21:36:35 2014 ericq UpdateGeneralVent so far

After turning the slow FSS threshold down, the mode cleaner stays locked enough to do other things. We were able to align the tip tilts to the y-arm such that we were able to get some flashes in what looks like a TM00-ish mode. (It was necessary to align the PRM such that there was some extra power circulating in the PRC to be able to see the IR flashes on the ITMY face camera) This is enough to convince us that we are at least near a reasonable alignment, even though we couldn't lock to the mode.

The x-arm was in a hairier situation; since the green beam wouldn't flash into any modes, we don't even know that a good cavity axis exists. So, I used the green input PZTs to shine the green beam directly on the earthquake stops on the ITMX cage, and then inferred the PZT coordinates that would place the green beam roughly on the center of ITMX. I moved the ETMX face camera such that it points at the ETMX baffle. I tried looking for the retroreflected green spot to no avail. Hopefully tomorrow, we can get ourselves to a reasonably aligned state, so we can begin measuring the macroscopic PRC length.

9580   Tue Jan 28 09:51:47 2014 SteveUpdateIOOlow power pointing

PSL output is stable.

Attachment 1: IOO4dlowpr.png
9581   Tue Jan 28 11:13:50 2014 KojiUpdateVAC vacuum monitor is still blank

[Steve Koji]

We pushed the reset button of c1vac1 and c1vac2 and the vacuum screen is back.

First, we pushed the reset button of c1vac1 and pushed the one on c1vac2.
This did not bring c1vac2 up. We pushed the reset of c1vac2 again and now everything of the vacuum screen is back.

9582   Tue Jan 28 16:26:40 2014 SteveUpdateVAC vacuum computers are back without safety

 Quote: [Steve Koji] We pushed the reset button of c1vac1 and c1vac2 and the vacuum screen is back. First, we pushed the reset button of c1vac1 and pushed the one on c1vac2. This did not bring c1vac2 up. We pushed the reset of c1vac2 again and now everything of the vacuum screen is back.

1, Reset works

2, Default values are lost. They actually reversed into open and turn on everything when power recycle c1vac1, c1vac2 or 24V dc power supply. This can vent the IFO in an event of power failure!

It's may be the time to go back to an isolated, vacuum controller only computer.

The present valve configuration at Atm1

a, all annuloses are vented

b, valve cables disconnected at: VC1 and 4 IP gate valves

c, the RGA is off and it is pumped by the Maglev through VM2

d, cryo pump is being roughed with TP3  It's outgassing rate was 25 mTorr / min

e, Roughing hose is disconnected

Attachment 1: c1vac1_vac2areback.png
9583   Tue Jan 28 22:24:46 2014 ericq UpdateGeneralFurther Alignment

[Masasa, ericq]

Having no luck doing things remotely, we went into the ITMX chamber and roughly aligned the IR beam. Using the little sliding alignment target, we moved the BS to get the IR beam centered on ITMX, then moved ITMX to get good michelson fringes with ITMY. Using an IR card, found the retroflection and moved ETMX to make it overlap with the beam transmitted through the ITM. With the PRM flashing, X-arm cavity flashes could be seen. So, at that point, both the y-arm and x-arm were flashing low order modes.

9584   Tue Jan 28 23:32:12 2014 KojiUpdateGeneralX/Y arm locked with the IR beam

[Koji EricQ]

The both arms have been locked with IR and aligned by ASS.

The IFO was left with ITMX/Y, ETMX/Y, BS, and PRM aligned, and the PSL shutter closed.

YARM
SIGNAL PATH:
POY11I(+45dB)->YARM(G=+1.0)->ETMY
NORM: TRYx10
TRIG: TRY 0.01up/0.005down
FM TRIG: FM2/3/6/7/8/9 0.01up/0.05down, 0.5 sec delay

XARM
SIGNAL PATH:
POX11I(+45dB)->XARM(G=+4.0)->ETMX
NORM: TRXx10
TRIG: TRX 0.01up/0.005down
FM TRIG: FM2/3/6/7/8/9 0.01up/0.05down, 0.5 sec delay

For decent locks, it was necessary that the offset of the error signals are trimmed at the input filters
even after running LSCoffset.py script.

Once the cavities were aligned for the IR, we could see the green beams are also flashing.
The Y arm was actually locked with the green with a TEM00 mode

Attachment 1: good_alignment.png
9587   Thu Jan 30 11:59:03 2014 manasaUpdateCDSfb timing was off

 Quote: Since this morning, the fb's timing has been off.  Steve pointed it out to me earlier today, but I didn't have a chance to look at it until now.  This was different from the more common problem of the mx stream needing to be restarted - that causes 3 red blocks per core, on all cores on a computer, but it doesn't have to be every computer.  This was only one red block per core in the CDS FE status screen, but it was on every core on every computer.  The error message, when you click into the details of a single core, was 0x4000.  I elog searched for that, and found elog 6920, which says that this is a timing issue with the frame builder.  Since Jamie had already set things on nodus' config correctly, all I did was reconnect the fb to the ntp:  `fb\$ sudo /etc/init.d/ntp-client restart ` As in elog 6920, the daqd stopped, then restarted itself, and cleared the error message. It looks like everything is good again. I suspect (without proof) that this may have to do with the campus network being down this morning, so the computers couldn't sync up with the outside world.

The above timing problem has been repeating (a couple of times this week so far). It does not seem to be related to the campus network.

The same solution was applied.

9589   Fri Jan 31 18:41:25 2014 manasaUpdateGeneralIFO alignment update

[EricQ, Gabriele, Manasa]

We found we had lost the Y arm pointing from yesterday. We tried to recover the pointing for a couple of hours and finally decided to take the ETMY heavy door off.

The input beam was aligned to the Y arm. We also got AS and REFL out of vacuum and on the cameras.

We put back the light doors and tried to lock the arms, but did not succeed as yet.

Things to do:
1. Lock arms for IR
2. Realign POP path
3. Recenter all oplevs
4. Try to check the state of PRC after the length change
5. Take in-vacuum pictures

9591   Mon Feb 3 10:17:14 2014 SteveUpdatePEMdusty surfaces

Please wet WIPE before opening chamber or optical table ! !

with methanol soaked kimwipes.

The Met One particle counter is located on CES wall, just behind ITMX chamber.

The numbers are not so bad, but have you ( ...a)  asked the IFO lately?

Attachment 1: AP-ISCT.jpg
Attachment 2: BSC-rim.jpg
Attachment 3: ITMX-ISCT.jpg
Attachment 4: 12daysAtm.png
9592   Mon Feb 3 15:57:52 2014 SteveUpdateGreen LockingETMX green power

There was 0.2 mW green at the X end.

The doubling oven temp was changed from 37.5 to 36 degrees C

Power at green shutter 3 mW  The alignment was not touched.

Attachment 1: ETMXgreen.jpg
Attachment 2: XgreenOven36C.jpg
9593   Mon Feb 3 23:31:33 2014 ManasaUpdateGeneralAlignment update / Y arm locked

[EricQ, Manasa, Koji]

We measured the spot positions on the MC mirrors and redid the MC alignment by only touching the MC mirror sliders. Now all the MC spots are <1mm away from the center.

We opened the ITMY and ETMY chambers to align the green to the arm. The green was already centered on the ITMY. We went back and forth to recenter the green on the ETMY and ITMY (This was done by moving the test masses in pitch and yaw only without touching the green pointing) until we saw green flashes in higher order modes. At this point we found the IR was also centered on the ETMY and a little low in pitch on ITMY. But we could see IR flashes on the ITMYF camera. We put back the light doors and did the rest of the alignment using the pitch and yaw sliders.

When the flashes were as high as 0.05, we started seeing small lock stretches. Playing around with the gain and tweaking the alignment, we could lock the Y arm in TEM00 for IR and also run the ASS. The green also locked to the arm in 00 mode at this point. We aligned the BS to get a good AS view on the camera. ITMX was tweaked to get good michelson.

9594   Tue Feb 4 00:42:18 2014 KojiUpdateGeneralX arm aligned for IR/GR

The X arm was also aligned for the IR by hand and ASS. Also the X end green PZT was aligned to make the TEM00 mode reasonably locked.

What I did:

- Looked at the ITMXF camera. It seemed that the green beam was hitting the mirror.

- Went to the end. Looked at the X end green REFL. Tuned coarse alignment of the ETMX so that the beam was (retro-)reflected to the Faraday and the REFL PD.

- Looked at the ETMX face from the view port. Tried to locate the spot from the ITMX by shaking the ITMX alignment with 0.1 and then 0.01 increments.

- After some struggle with the ETMX and ITMX alignment, resonant fringes were found on the ETMY face while I still looked at the ETMX.

- Once the ITMX/ETMX were aligned, the BS needed to be aligned. But of course there was no IR fringe.

- Returned to the original alignment of the ITMX to find the ITMX spot on the AS camera.
Then gradually moved the ITMX to the aligned value for the green while tracking the michelson alignment with the BS.
This made the AS spots at the upper left edge of the AS video image.

- This was enough to find the IR spikes at TRX. Then the ETMX was touched to maximize the transmission.

- Lock the cavity. Use the ASS to optimize the alignement.

- Once the arm mirrors were aligned, the Xend PZT was also adjusted to have TEM00 for the green beam.

Now I leave the IFO with ITMX/Y, ETMX/Y and BS aligned. As I wrote above, the AS spot is very high at the AS camera.
We need to revisit the AS steering (SR TTs?) to ensure the AS beam unclipped.

9595   Tue Feb 4 01:02:03 2014 KojiUpdateGreen LockingETMX green power

# Manasa, Steve: Please revisit the Xend oven temperature again.

I found that the X end SLOW control was left on for ~15days. The output of the filter had grown to ~2e7.

This yielded the laser temperature pulled with the maximum output of the DAC.

This was the cause of the power reduction of the X end SHG; phase matching condition was changes as the wavelength of the IR was changed.

Once the SLOW output was reset, the green REFL was reduced from 4000cnt to 1800cnt.

Attachment 1: Screenshot-Untitled_Window.png
9596   Tue Feb 4 16:43:50 2014 manasaUpdateGeneralIFO alignment update

[EricQ, Manasa]

We are close to the end of the vent except for a couple of issues.

* POP is not visible on the IR card. But we see POP flashes unclipped on the camera and also spikes in POP DC. So  we are assuming that the POP path hasn't gone far off. If anybody has suggestions for a better method to check this, we could give it a try.

* PRM suspension has not been behaving well. PRM is being kicked around every 5-10 seconds when the PRC is aligned (as seen on REFL camera). We are not sure where this is coming from. The first time we saw this happening was when we were trying to lock PRC at low power even before we took the heavy doors off. So we are pretty sure this is not caused by the foil cover on the OSEMs. We tried turning ON/OFF the oplev servo, turning ON/OFF the damping loops and also checked the connections in the feedthrough and satellite box for the PRM. The OSEM sensor values for the suspension also seem to match the ones on the wiki.

# Closeup checklist

• Center beam on all AS optics
• GET CAMERA IMAGES OF EVERYTHING

• We must get images right before closing, right after closing, etc.
• Make sure REFL is clear
• dither PRM, see motion on AP tables
• Make sure AS is clear
• dither BS/ITM, see motion on AP tables
• Using IPANG/POS pick-off mirrors, center beams on:
• IPPOS
• IPANG (IPANG aligned to be low in pitch. The beam comes out of vacuum unclipped and hits the first steering mirror outside vacuum at its lower edge)
• Check green alignment in the arms and make sure the transmitted green reaches the PSL table.
• Check all OpLevs centered, in and out of vacuum

• Close PSL shutter & green shutters at the ends

• Check jam nuts
9597   Tue Feb 4 17:40:19 2014 manasaUpdateGeneralReady for pump down??

 Quote: * PRM suspension has not been behaving well. PRM is being kicked around every 5-10 seconds when the PRC is aligned (as seen on REFL camera). We are not sure where this is coming from. The first time we saw this happening was when we were trying to lock PRC at low power even before we took the heavy doors off. So we are pretty sure this is not caused by the foil cover on the OSEMs. We tried turning ON/OFF the oplev servo, turning ON/OFF the damping loops and also checked the connections in the feedthrough and satellite box for the PRM. The OSEM sensor values for the suspension also seem to match the ones on the wiki.

This is solved.

The ASC for PRC for left turned ON. Turning it OFF solved the problem.

If there is no feedback regarding the POP alignment or anything to check with modified PRC length, we will close tomorrow morning.

9598   Tue Feb 4 23:01:24 2014 JenneUpdateGeneralReady for pump down??

This sounds great! The only suggestion that I have is for checking POP. If you have the beam on the camera, you can hold a card in front of each mirror, and find out where the edge of the beam is. Introduce the card from the side, and watch for the point where you just start to see the beam on the camera be obstructed. Repeat for the other side, and you have an idea of the centering of the beam.

I think this is most important for the in-vac mirrors, since the beam is large-ish, and we have to hit both steering mirrors at ~45 degrees.

9599   Wed Feb 5 08:14:59 2014 SteveUpdateVAC vacuum computers are back without safety

 Quote: 1, Reset works  2, Default values are lost. They actually reversed into open and turn on everything when power recycle c1vac1, c1vac2 or 24V dc power supply. This can vent the IFO in an event of power failure!       It's may be the time to go back to an isolated, vacuum controller only computer.   The present valve configuration at Atm1 a, all annuloses are vented b, valve cables disconnected at: VC1 and 4 IP gate valves c, the RGA is off and it is pumped by the Maglev through VM2 d, cryo pump is being roughed with TP3  It's outgassing rate was 25 mTorr / min e, Roughing hose is disconnected

Vacuum checks before pump down:

1, check intermittent contact issue in black relay box

2, reconnect cable to ion pumps and vent them to atm before pump down

3, repeat power shutdown-reboot at atmosphere

9600   Wed Feb 5 09:28:32 2014 SteveUpdateSUSETMY damping restored

ETMY damping restored.

9601   Wed Feb 5 15:26:57 2014 manasaUpdateGeneralReady for pump down??

 Quote: This sounds great! The only suggestion that I have is for checking POP. If you have the beam on the camera, you can hold a card in front of each mirror, and find out where the edge of the beam is. Introduce the card from the side, and watch for the point where you just start to see the beam on the camera be obstructed. Repeat for the other side, and you have an idea of the centering of the beam.  I think this is most important for the in-vac mirrors, since the beam is large-ish, and we have to hit both steering mirrors at ~45 degrees.

[EricQ, Manasa]

This check was done and we had to move one of the steering mirrors in pitch. Else, everything was just fine.

In-vacuum pictures of PR2 and PR3 new positions were taken. MC spot positions measured to be < 1mm and oplevs were centered.

9602   Wed Feb 5 15:39:41 2014 manasaUpdateGeneralWe are pumping down

[Steve, Manasa]

I checked the alignment one last time. The arms locked, PRM aligned, oplevs centered.

We went ahead and put the heavy doors ON. Steve is pumping down now!

Attachment 1: pre_pump_down.png
9604   Wed Feb 5 19:36:50 2014 SteveUpdateVACpumpdown at 25 Torr

 Quote: [Steve, Manasa] I checked the alignment one last time. The arms locked, PRM aligned, oplevs centered. We went ahead and put the heavy doors ON. Steve is pumping down now!

The ion pumps were vented just before pumpdown and their gate valves were opened.

This is an effort to minimize a possible leak through their gates.

Is there a volunteer who goes home late and would close off the roughing? tonight

Attachment 1: pd77at3.5h.png
9605   Wed Feb 5 19:53:51 2014 SteveUpdateVACpumpdown stops for the day at 14 Torr

Attachment 1: stopHere.png
9606   Wed Feb 5 20:41:57 2014 DenUpdateLSCcalibrated spetra from OAF test

We did online adaptive filtering test with IMC and arms 1 year ago (log 7771). In the 40m presentations I can still see the plot with uncalibrated control spectra that was attached to that log. Now it the time to attach the calibrated one.

Template is in the /users/den/oaf

Attachment 1: oaf_cal.pdf
9607   Thu Feb 6 11:14:07 2014 SteveUpdateVACpumpdown completed

Pumpdown completed. IR shutter opened at P1 1 mTorr  The block is still in the beam path.

Remember to protect MCR pd before crack up the PSL power.

The ion pump gate valves were just closed by cc1 triggered interlock

The cry pump was "regenerated" during the vent and it's outgassing rate minimized.

CC3 cold cathode gauge was replaced.

Valve configuration for week end:

1, VA6 disconnected to avoid accidental venting the IFO through the annulos

2, VC2 disconnected to insure that the cryo stays closed

3, RGA is not running, It's pressure limit 1e-5 Torr

Attachment 1: pd77.png
9608   Thu Feb 6 16:41:31 2014 ericqUpdateGeneralIn-Vac Alignment

[Manasa, ericq]

Both arms have been aligned via ASS. PRC locked on carrier.

SB locking hasn't happened yet...

Details:

• Aligned MC at low power, measured spots
• Found ITMX AS, REFL spots on cameras. Couldn't find ITMY spot. Found x-arm flashes with PRM aligned.
• MC Refl Y1 mirror was replaced with the 90:10 BS; blocked WFS path until MC was aligned
• PMC power was increased (~1.4W directly before PSL shutter)
• Touched up MC alignment, reactivated high power autolocker, measured spots.
• Locked x-arm on IR, ran ASS
• Found ITMY spot on AS camera, locked y-arm, ran ASS on both arms
• Checked green beams. Y-arm locks at around .6, X-arm at around .2 (input steering needs adjustment)
• Centered beams on WFS, reset filter bank offsets, turned on WFS
• Aligned PRM, locked PRC on carrier.
• Tried locking PRC on sideband, had troubles. Looks like there is some increased seismic activity; might be the culprit.

9609   Fri Feb 7 12:43:12 2014 ericqUpdateGeneralIn-Vac Alignment

[ericq]

PRC Locked on Sidebands

Jenne reminded me that if we change a cavity, phases can change... So, first, I locked the PRC on the carrier, and then gave it MICH and PRCL excitations to optimize the AS55 and REFL55 phase rotation angles by looking at the excitation demodulated outputs of the unused quadrature (i.e. we want all of MICH to be in AS55 Q, so I rotated the phase until C1:CAL-SENSMAT_MICH_AS55_I_I_OUTPUT was zero on average).

This resulted in:

• AS55: 7 -> -5.5
• REFL55: 73 -> 86.9

I then used the same settings as in ELOG 9554, except I used -1s instead of +1s for the POP110I trigger matrix elements. (I'm not sure why this is different, but I noticed that the PRC would lock on carrier with positive entries here, so I figured we wanted the peaks with opposite sign).

So far, it seems more stable than when we were doing the demodulation phase measurements, it's been locked for >15 minutes without me having to tweak the gains or the alignment from the carrier locked case.

9610   Fri Feb 7 13:00:52 2014 JenneUpdateGeneralIn-Vac Alignment

 Quote: I then used the same settings as in ELOG 9554, except I used -1s instead of +1s for the POP110I trigger matrix elements. (I'm not sure why this is different, but I noticed that the PRC would lock on carrier with positive entries here, so I figured we wanted the peaks with opposite sign).

Nice work!!  As with all the other RF PDs, POP110's phase likely needs tuning.  You want POP110 (and POP22) I-quadratures to be maximally positive when you're locked on sidebands, and maximally negative when locked on carrier.  What you can do to get close is lock PRC on carrier, then rotate the POP phases until you get maximally negative numbers.  Then, when locked on sideband, you can tweak the phases a little, if need be.

9611   Fri Feb 7 13:30:22 2014 GabrieleUpdateGeneralIn-Vac Alignment

Quote:

 Quote: I then used the same settings as in ELOG 9554, except I used -1s instead of +1s for the POP110I trigger matrix elements. (I'm not sure why this is different, but I noticed that the PRC would lock on carrier with positive entries here, so I figured we wanted the peaks with opposite sign).

Nice work!!  As with all the other RF PDs, POP110's phase likely needs tuning.  You want POP110 (and POP22) I-quadratures to be maximally positive when you're locked on sidebands, and maximally negative when locked on carrier.  What you can do to get close is lock PRC on carrier, then rotate the POP phases until you get maximally negative numbers.  Then, when locked on sideband, you can tweak the phases a little, if need be.

Very good news! We should have a look at the POP110 sideband peak splitting, to see if we really got the right PRC length...

9612   Fri Feb 7 13:30:25 2014 ericqUpdateGeneralIn-Vac Alignment

 Quote: Nice work!!  As with all the other RF PDs, POP110's phase likely needs tuning.  You want POP110 (and POP22) I-quadratures to be maximally positive when you're locked on sidebands, and maximally negative when locked on carrier.  What you can do to get close is lock PRC on carrier, then rotate the POP phases until you get maximally negative numbers.  Then, when locked on sideband, you can tweak the phases a little, if need be.

Adjusted the angles as Jenne suggested:

• POP22: 105 -> 163
• POP110: 150 -> -83
9614   Sat Feb 8 15:14:18 2014 ericqUpdateLSCPRM Sideband Splitting

[ericq]

Today, I kicked the PRM to see the sideband splitting in POP110.

First, we can qualitatively see we moved in the right direction! (See ELOG 9490)

I fit the middle three peaks to a sum of two Lorentzian profiles ( I couldn't get Airy peaks to work... but maybe this is ok since I'm just going to use the location parameter?), and looked at the sideband splitting as a fraction of the FSR, in the same way as in Gabriele's ELOG linked above.

This gave: c / (4 * f55) * (dPhi / FSR) = 0.014 +- .001

Since the PRC length with simultaneous resonance (to 1mm) is given by c / (4 * f11) = 6.773, this means our length is either 6.759m or 6.787m (+- .001). Given the measurement in ELOG 9588, I assume that we are on the short side of the simultaneous resonance. Thus

The sideband splitting observed from this kick indicates a PRC length of 6.759m +- 1mm

9615   Mon Feb 10 09:45:53 2014 SteveUpdateVACvacuum normal is reached

 Quote: Pumpdown completed. IR shutter opened at P1 1 mTorr  The block is still in the beam path. Remember to protect MCR pd before crack up the PSL power. The ion pump gate valves were just closed by cc1 triggered interlock The cry pump was "regenerated" during the vent and it's outgassing rate minimized. CC3 cold cathode gauge was replaced.   Valve configuration for week end: 1, VA6 disconnected to avoid accidental venting the IFO through the annulos 2, VC2 disconnected to insure that the cryo stays closed 3, RGA is not running, It's pressure limit 1e-5 Torr

Valve configuration:       Vacuum Normal    is reached in really 4 days if we do not count overnight rest of roughing.

VA6 and VC2 are reconnected. I'm turning on the RGA next

All 4 ion pumps were vented with air and pumped down to ~ 1e-4 Torr

Ion pumps gate valve control cables are connected and their pumps are disconnected.

The black relay box was tested repeatedly and it stopped misbehaiving.

We were at atmosphere for 13 days.  Chamber BS, ITMX, ITMY and ETMY were opened.

Al foil "cups" were placed on the back side OSEMs of PRM.

Attachment 1: pd77m5d.png
Attachment 2: 13daysAtm.png
9616   Mon Feb 10 16:02:12 2014 JenneUpdateGeneralPRM oplev clipped in vacuum

The PRC (locked on carrier so far today), is pretty wobbly.  It'll stay locked on carrier, but it's wobbling.  The ASC was over-ridden during the vent.  While I was looking around for that, I noticed that the PRM oplev sum is very low.

I went into the lab, and turned off / blocked all oplev beams except the PRM beam.  I can't tell what it's clipping on, but there is definitely some red glow in the BS chamber (not as much as the stuff that's coming from the ITMY or SRM oplev hitting a tip tilt suspension - that giant spot went away when I turned off the ITMY/SRM oplev laser).  The beam going into the vacuum is nice and strong, but the beam coming out is very weak, and has a horizontal line of scatter through it, like it's clipped somewhere in pitch.  The PRM oplev sum is currently ~150 cts, when it should be closer to 2,000.

So far, this seems to be livable, but it's definitely disappointing.

9617   Mon Feb 10 16:20:28 2014 JenneUpdateGeneralPRM QPD recentered

In an effort to stop the PRC from wiggling around so much, I recentered the POP QPD after maximizing the POPDC power when locked on carrier.  The beam was basically off the QPD in yaw, and at half-range in pitch.

9618   Mon Feb 10 18:03:41 2014 jamieUpdateCDS12 core c1sus replacement

I have configured one of the spare Supermicro X8DTU-F chassis as a dual-CPU, 12-core CDS front end machine.  This is meant to be a replacement for c1sus.  The extra cores are so we can split up c1rfm and reduce the over-cycle problems we've been seeing related to RFM IPC delays.

I pulled the machine fresh out of the box, and installed the second CPU and additional memory that Steve purchased.  The machine seems to be working fine.  After assigning it a temporary IP address, I can boot it from the front-end boot server on the martian network.  It comes up cleanly with both CPUs recognized, and /proc/cpustat showing all 12 cores, and free showing 12 GB memory.

The plan is:

1. pull the old c1sus machine from the rack
2. pull OneStop, Dolphin, RFM cards from c1sus chassis
3. installed OneStop, Dolphin, RFM cards into new c1sus
4. install new c1sus back in rack
5. power everything on and have it start back up with no problems

Obviously the when of all this needs to be done when it won't interfere with locking work.  fwiw, I am around tomorrow (Tuesday, 2/11), but will likely be leaving for LHO on Wednesday.

9619   Mon Feb 10 18:59:25 2014 JenneUpdateASCPRM ASC better, but not great yet

I have turned off the 3.2Hz res gains in the PRC ASC loops, since those seem to make the loops unstable.

Right now the pitch gain is -0.001, with FM1,3,9 on.  Yaw gain is -0.004, with FM1,3,9 on.

Pitch gain can't increase by factor of 2 without oscillating.

I tried to take transfer functions, but I think the ASC situation is really confusing, since I have OSEM damping, oplev damping, and this POP QPD damping on the PRM.  It's hard to get coherence without knocking the PRC out of lock, and it keeps looking like my gain is 0dB, with a phase of 0 degrees, from ~1 Hz to ~10 Hz.  Outside that range I haven't gotten any coherence.  Moral of the story is, I'm kind of puzzled.

Anyhow, as it is right now, the ASC helps a bit, but not a whole lot.  I increased the trigger ON value, so that it shouldn't kick the PRM so much.  I wish that I had implemented a delay in the trigger, but I'm not in the mood to mess with the simulink diagrams right now.

9620   Mon Feb 10 19:56:10 2014 ranaUpdateASCPRM ASC better, but not great yet

Ignoring the OSEM damping loops, the oplev servo loops make it so that the POP ASC loops do not see a simple pendulum plant, but instead see the closed loop response. Since the filter in the OL bank is proportional to f, this means that the open loop gain (OLG):

$OLG = \frac{s^2}{s0^2 + i*s0*s/Q +s^2}$

Which means that the CLG that the ASC sees is going to dip below unity in the band where the OL is on. For example, if the OL loop has a UGF of 5 Hz, it also has a lower UGF of ~0.15 Hz, which means that the ASC needs to know about this modified plant in this band.

For i/eLIGO, we dealt with this in this way: anti-OL in iLIGO

9621   Mon Feb 10 22:21:55 2014 manasaUpdateGreen LockingX and Y arm green tuned

Y arm green: Nothing much was disturbed. I touched the steering mirrors and brought GTRY from 0.2 to 0.9.

X arm green: The PDH lock was not very stable mostly because of the low power in green. I changed the oven temperature for the doubler to 36.4 corresponding to maximum green power. GTRX increased from 0.1 to 0.9

Both the X and Y arm green alignment were tuned on the PSL table to their respective beat PDs.

The PSL green shutter was not responding to the medm buttons. I found the PSL green shutter set to 'local' and 'N.O' (these are switches in the shutter controller). I do not see any elog and not sure as to why the controller was even touched in the first place. I set the shutter controls to 'remote' and 'N.C'.

9622   Tue Feb 11 10:44:15 2014 SteveUpdateVACRGA scan at day 6

Attachment 1: pd77m6d.png
9623   Tue Feb 11 16:49:36 2014 SteveUpdatePEM floor cleaning

Keven, Steve

The floor was cleaned under the east arm tube with hand held wet towel. We moved staff around and mopped. I did at the bottom of rack  1Y1, 2  and 3.

Last week we did the south arm tube floor.

Next week we 'd like to clean under rack 1X1,2,3, 4, 5, 6 and 7

9624   Tue Feb 11 21:22:02 2014 manasaUpdateGreen LockingALS X and Y arm restored

The X and Y arms were locked successfully using ALS and the arms could be scanned and held to support IR resonance.

The same procedure as in elog 9219 was followed. In-loop noise was measured to be between 200-300 Hz rms for the lock.

ALS settings for the lock

X arm : FM 2, 3, 5, 6, 7, 8, 10  Gain = 11.0
Y arm : FM 2, 3, 5, 6, 7, 8, 10  Gain = 10.0

9625   Tue Feb 11 22:17:06 2014 KojiUpdateGreen LockingALS X and Y arm restored

Nice restoration. We eventually want to make transition of the servo part from ALS to LSC model for the further handing off to the other signals.
Please proceed to it.

9626   Wed Feb 12 11:57:55 2014 JenneUpdateLSCMusings on RFPDs

[Rana, Jenne, Manasa]

We looked at the I vs. Q separation in several of the Refl PDs, while driving the PRM, while the  PRMI was locked on sidebands.

For REFL 55, we adjusted the demod phase to try to minimize the peak in the Q signal, and were only able to get it to be about 1/10th the size of the I peak.  This is not good, since it should be more like 1/100, at least.

For both REFL 11 and REFL 165, we were able to get the Q peaks to less than 1/100 of the I peak height.

We changed the REFL55 phase from 17 to 16, and the REFL165 phase from -160.5 to -162.5.

Since we believed that we had done a good job of setting the demod phase for REFL165, we used it to also check the balance of BS/PRM for MICH locking.  I drove the BS with an arbitrary number (0.5), which creates a peak in the I phase of REFL165, and then I put in a drive on the PRM and tweaked it around until that peak was minimized.  I came up with the same ratio as Koji had last Friday:  BS=0.5, PRM=-0.2625.  (The old ratio we were using, up until ~December when we started locking MICH with the ITMs, was BS=0.5, PRM=-0.267).

Also, while we were locked using REFL55 I&Q, we noticed that the other REFL PDs had lots of broadband noise in their I signals, as if some noise in the REFL55 diode is being injected into the PRM, that we are then seeing in the other PDs.

Some checks that we need to do:

* Inject a calibration line, set all the peak heights equal, and look at the noise floors of each PD.

* Use the calibration line to calibrate the PDs (especially REFL165) into meters, so that we know that it's noise is low enough to hold the PRC through the CARM offset reduction.

* Check out the state of the transmission QPDs - what is their noise, and is it good enough to use for holding the arms after we transition from green beatnote locking?  Does the whitening switching do anything?  What is the state of the whitening?

ELOG V3.1.3-