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ID Date Authorup Type Category Subject
  7610   Wed Oct 24 17:02:01 2012 JenneUpdateAdaptive Filteringmicrophone noise


  We have to change the sample rate and AA filter for the mic channels before going too far with the circuit design.

 To save the mic channels at higher than 2k (which we should do), we either have to move them to a different model, change the rate of the PEM model, or see if you can save data faster than the model runs (which I can't imagine is possible).

  7625   Thu Oct 25 20:44:11 2012 JenneUpdateSUSTip tilts in progress

Jamie and I spent some time with tip tilt SN001 this afternoon.  This was installed as SR3, so I was going to put a new LaserOptik mirror in there.  I accidentally snapped one of the wires (I forgot how strong the magnets are - one zipped from the mirror holder and captured the wire).  Jamie and I put the new LaserOptik mirror in, with the wedge correct, but we need to re-resuspend it with the 0.0036" wire tomorrow.  We'll also keep working on re-pitch aligning the other optics.

PR2 needs to be put back as a G&H, and we need to put a LaserOptik mirror into PR3.

  7630   Fri Oct 26 10:44:25 2012 JenneUpdateSUSTip tilts in progress


Jamie and I spent some time with tip tilt SN001 this afternoon.  This was installed as SR3, so I was going to put a new LaserOptik mirror in there.  I accidentally snapped one of the wires (I forgot how strong the magnets are - one zipped from the mirror holder and captured the wire).  Jamie and I put the new LaserOptik mirror in, with the wedge correct, but we need to re-resuspend it with the 0.0036" wire tomorrow.  We'll also keep working on re-pitch aligning the other optics.

PR2 needs to be put back as a G&H, and we need to put a LaserOptik mirror into PR3.

 We resuspended SN001 this morning with 0.0036" wire.  We did as Koji suggested, and flipped the wire clamp so the suspension point is a little higher, so we'll see if that helps.  We put LaserOptik mirror SN1 into this TT001.

We put the G&H mirror back into TT004, which is PR2.  We also put a LaserOptik mirror (SN5) into TT005, which is SR3.

Jamie is working on re-pitch aligning TT004 and TT005 (we already did 001), then we can re-install them in the vacuum system later this afternoon.

  7631   Fri Oct 26 13:08:14 2012 JenneUpdateSUSTip tilts in progress



Jamie is working on re-pitch aligning TT004 and TT005 (we already did 001), then we can re-install them in the vacuum system later this afternoon.

 The tip tilts have all been pitch-adjusted now, and they have all been put back onto the tables, with the same serial numbers in the same places as we took them out.  Jamie also re-leveled the BS table.

Raji and I will align things after I finish measuring the MC spot positions.

  7632   Fri Oct 26 16:57:30 2012 JenneUpdateAlignmentPR2 aligned, PR3 mostly aligned

[Raji, Jenne]

After lunch we began where Raji and Jamie had left things.  PR2 was unfortunately pitched down so far that it was almost hitting the table just in front of PR3.  I loosened the 4 clamp screws that hold the wire clamp assembly to the mirror holder, and tapped it back and forth until I was within hysteresis range, re-tightened, then tapped the top and bottom until we were at the correct beam height just in front of PR3.  I also had to unclamp it from the table and twist the base a tiny bit, since the beam was closer to hitting the beam tube than the optic.  Finally, however, PR2 is adjusted such that the beam hits the center of PR3.

Moving on to PR3, the pitch looked good while we were looking at the aperture placed near the face of ITMY, so we left that alone.  The beam is off in yaw though.  Several times I unclamped the tip tilt from the table, and twisted it one way or another, but every time when I tighten the dog clamps, I'm too far off in yaw.  The beam points a little too far south of the center of ITMY, so we were putting the beam a little north of the center before I clamped it, but even tightening the screws in the same order, by the same amount each time, causes a different amount of slipping/twisting/something of the TT mount, so we never end up directly in the center of the ITM.  It seems a little like a stochastic process, and we just need to do it a few more times until we get it right. 

We left it clamped to the table, but not in it's final place, and left for JClub.  On Monday morning we need to go back to it.  As long as we're pretty close to centered, we should probably also have someone at ETMY checking the centering, because we need to be centered in both ITMY and ETMY.

We have not touched the SR tip tilts, so those will obviously need some attention when we get to that point.

  7641   Mon Oct 29 18:50:02 2012 JenneUpdateAlignmentPRC aligned, Yarm almost aligned

[Jamie, Jenne, Raji, with consultation from Nic, Ayaka and Manasa]

We went back and re-looked at the input alignment, and now we're "satisfied for the moment" (quote from Jamie) with the PRC alignment.  Also, by adjusting the PR folding mirrors, we are almost perfectly aligned to the Yarm.

What we did:

Set PRM DC biases to 0 for both pitch and yaw.

Aperture was attached to PRM cage, double aperture was attached to BS cage, free-standing aperture was placed in front of PR2. 

Adjusted PZT1, PZT2 such that we were centered on PZT2, and through apertures at PRM and PR2.   This was mainly for setting beam height in PRC.

Checked centering on PZT1, MMT1, MMT2, PZT2.

Adjusted PRM pitch bias and PZT2 yaw such that REFL beam was retro-reflected from PRM.

Checked that REFL beam came nicely out of Faraday.

Checked that beam was still going through center of PRM aperture, and pitch height at PR2 was good.

Moved PR2 sideways until beam hit center in yaw of PR2.

Twisted PR2 such that beam was hitting center of PR3.

Moved and twisted PR3 (many times) so that beam went through BS input and output apertures, and through center of ITMY aperture.

Found that beam was just getting through black glass aperture at ETMY, top left corner, if looking at the face of ETM from ITM.

Locked down dog clamps on PR2.

This required some re-adjustment of PR3.  Re-did making sure going through BS apertures and ITMY aperture, locked down PR3 dog clamps.

Found that we are centered in yaw at ETMY, a little high in pitch on ETMY.

Replaced all of the light doors, to take a break.  4 hours in bunny suits seemed like enough that we earned a break.

This all sounds more straighforward than it was.  There was a lot of iteration, but we finally got to a state that we were relatively happy with.


What we will do:

Tweak PZT2 a *tiny* bit in pitch, ~0.5 mrad, so that the beam goes through the ETMY aperture.

See if we can align EMTY and ITMY to get multiple bounces through the Yarm.

Remove ETMX heavy door, steer BS such that we're getting through the center of an aperture at ETMX.

Align ETMX and ITMX such that we get multiple bounces through the Xarm.

Check SRM, AS path alignment.

Check REFL out of vac alignment.

Check other pickoffs.

Check all oplevs.



We have a open-sided 2" mirror mount that we are considering using for the POY pick-off mirror.  This might help us get a little more clearance in the Y-arm of the Michelson.  Problem is the mount is not steerable, so we need to determine if that's doable or not.


  7642   Tue Oct 30 11:51:45 2012 JenneUpdateAlignmentPRC aligned, Yarm almost aligned

[Raji, Jenne]

We tweaked PZT2, PZT1 (yaw only), and PR3 (pitch only) to get the beam ~centered on the BS aperture, the ITMY aperture, and the ETMY aperture.

After lunch I'll tweak up the MC alignment, since, although the spots are in the right places, the transmitted beam could be higher power.  This will make it easier to check our pointing, especially since the ETMY spot is larger than our aperture, but the beam is dim.

We're getting there!

  7647   Wed Oct 31 17:18:34 2012 JenneUpdateAlignmentprogress, then setback - trend of BS table shift

Here is a two hour set of second trends of 2 sensors per mirror, for BS, PRM, ITMY and MC1.  You can see about an hour ago there was a big change in the BS and PRM suspensions, but not in the ITMY and MC1 suspensions.  This corresponds as best we can tell with the time that Jamie was figuring out and then fixing PZT2's mount.  You can see that the table takes some time to relax back to it's original position.  Also, interestingly, after we put the doors on ~10 or 20 minutes ago, things change a little bit on all tables. This is a little disconcerting, although it's not a huge change.

Attachment 1: PRM_BS_table_bumped_ITMY_MC1_no_big_change_2hoursBack.png
  7658   Thu Nov 1 19:28:48 2012 JenneUpdateAlignmentaligned, AS beam on camera

After everyone else did the hard work, I moved the AS first-on-the-table steering mirror sideways a bit so the AS beam is on the center of the mirror, then steered the beam through the center of the lens, onto the 2" 99% BS.  I also moved the camera from it's normal place (the 1% transmitted through that BS) to the AS110 PD path, as we did last vent.  We'll need to put it back before we go back to high power.

  7662   Fri Nov 2 14:37:36 2012 JenneUpdateGeneralOpen-sided mount - why



Suprema- SS clear edge mirror mount 2" diameter is modified for 40m vacuum use. One left and one right handed one. It's adjustment screw housing is bronze! It is not ideal for out gassing.

It will be baked and scanned. If it passes we should use it.

We may need these to bring out some pick-off beams.

 I vote against it. We don't know about the grease inside the screw bushings - scans are not everything if adjusting the screw loosens up the grease. If we need more pick off mirrors lets just make some of the kind that we already use inside for the 2" optics.

 I think Steve had these prepared in response to my question a few days ago of how badly do we need adjustability for the POX/POY mirrors?  We already have cleaned open-sided mounts that have no adjustment screws.  So as long as the beam reflects off the ITMs horizontally (which it should), we can do yaw adjustment by twisting the whole mount. We don't need super fine yaw adjustment, we just need to get the beam out, so this is probably good enough.

We should put the POY mirror on this open-sided mount (the one without screws) some time.  Perhaps even today.

  7664   Fri Nov 2 19:59:54 2012 JenneUpdateAlignmentPOP, POX, POY, IPPOS, IPANG, REFL all coming out of vac

[Evan, Jenne, Jamie]

We used the green laser pointer technique to adjust the POP steering mirrors behind PR2 to get the POP backward beam out onto the table (rather, the mirrors were adjusted so that the green laser pointer, mounted on the POX table, was co-aligned with the beam between PR2 and PR3).

We were unable (why? I feel like it wasn't so hard last time) to see the POX beam, with a camera pointed at an IR card.  We ended up just waving a lens-free CCD camera around on the POX table where we expected POX to be, found the beam, and decided that if the beam was getting to the table, that was good enough.

We then waved the camera around on the POY table, and found the POY beam on the table.  We also moved ITMY up and down in pitch, and saw that the POY beam was moving, so we were satisfied that we had the correct beam.  We should go back and do this same check with POX, although I'm pretty sure that we already have the correct beam.  But checking is good.

We confirmed that IPPOS was coming out of the chambers.  I didn't end up touching any in-vac mirrors for IPPOS, since they all looked centered, and the beam on the table was already centered on the steering mirror on the out-of-vac table.

We got IPANG out of the chamber to the ETMY table.  IPANG has, after the pickoff window, an adjustable mirror, and then a fixed mirror on the BS table.  The beam was very close to the edge, in yaw, on that fixed mirror.  Jamie unclamped it and moved it so the beam was centered, then twisted it until I got beam back down at the end, centered on the first steering mirror down there.  Then Evan and I got the beam centered on the other steering mirror on the in-vac ETMY table, and got the mirror to ~the center of the first out-of-vac steering mirror.  Then Evan adjusted the other steering optics so the beam was hitting the QPD.

We then got the real REFL beam out of the chambers.  I still don't know what that ghost/fake beam is.  Anyhow, we moved PRM around, and saw that the real REFL beam moves, while the fake one doesn't.  We adjusted the adjustable REFL steering mirror in-vac such that the real REFL beam came out to the table.  Once on the AP table, we moved the PRM around again, just to be doubly/triply sure that we had the correct beam.  We put a beam splitter (found on the SP table) after the lens in the REFL path on the AP table, and put the camera on the reflected side of that BS.  This is because, like the AS port, the beam is too dim at the normal camera spot (which for REFL is the transmission through a Y1 mirror).

Jamie has centered IPPOS and IPPANG QPDs, so we should look at the weekend trend come Monday, to see what things look like, and how they drift, if at all.


On Monday, we should:

* Check the alignment, and the centering of beams on all mirrors one last time

* Remove all apertures from suspended optics (I think BS and PRM may be the only two that have them at this time)

* Check oplev paths for all mirrors

* Check all pickoffs / beams that need to come out of the vacuum

* Start putting on doors

  7665   Fri Nov 2 20:41:53 2012 JenneUpdateAlignmentAS, REFL camera shots

These don't show anything too interesting, but we're including them to show where the beams are right now on the cameras, so we can compare on Monday.









  7668   Mon Nov 5 09:53:35 2012 JenneUpdateAlignmentAS, REFL camera shots

Today's photos:





IPANG / IPPOS trends:



 c.f. screen caps from Friday:


These don't show anything too interesting, but we're including them to show where the beams are right now on the cameras, so we can compare on Monday.










  7683   Wed Nov 7 15:51:44 2012 JenneUpdateAlignmentJamie's tip tilt proposal

Steve's elog 7682 is in response to the conversation we had at group meeting re: Jamie's proposed idea of re-purposing the active tip tilts.

What if we use the active TTs for the PR and SR folding mirrors, and use something else (like the picomotors that Steve found from the old days) for our input steering?

  7685   Wed Nov 7 19:07:45 2012 JenneUpdateCamerasNo beam seen on external camera views

I have written some scripts which collect photos, then average them together, and subtract out an averaged background (as Rana described in elog 7678). 

I am not seeing any beam spots on any of the resulting pictures. 


The script to get 500 pictures is


and it's inputs are {name of camera} {folder to save in} {noBeam or withBeam}, where noBeam and withBeam indicate whether or not the PSL shutter is closed.  For the saved photos to work nicely with the Matlab script, the folder to save in should be in the format (Month_day_year/CAMERA).  So today's ITMYF pics, for example, are in Nov_7_2012/ITMYF/ .

So, you run it once with the shutter open, and once again with the shutter closed.


To create the new picture, open ImageBkgndSubtractor.m in the same .../scripts/general/videoscripts folder, edit the top few lines (month, day, year, camera name).  Run it, and it will read through all the pictures and supply a background-subtracted output, and save the output (as well as a version where every pixel value is multiplied by 3) in the same folder as the 500 pictures.

The pictures are all saved in


so really, for my example above, it would be /opt/rtcds/caltech/c1/scripts/general/videoscripts/photos/Nov_7_2012/ITMYF/, with 2 subfolders, noBeam and withBeam, and the final pictures are saved in /opt/rtcds/caltech/c1/scripts/general/videoscripts/photos/Nov_7_2012/ITMYF/ .


In other, semi-unrelated news, the ITMXF camera has been not working for a while.  The bottom right quad on the test mass tv has been dark for at least a week or two.  Steve, when you have a chance (after the oplevs are all taken care of), can you see if there's something obvious that's wrong?

Here are the background subtracted photos that I've taken today:






MC2F is included, even though you can see the spot usually, just to prove that I'm not trying to subtract away the spot!  You just can't see it in any other picture.

  7689   Thu Nov 8 20:11:54 2012 JenneUpdateAlignmentAS steering moved out of POY's way, 2 green beams onto PSL table

[Jenne, Jamie, Manasa, Ayaka]


Flipped mount of OM2, moved OM2 behind POY pickoff so we're out of the way of POY.  Adjusted and recovered rest of AS path.

We found that IPANG was not on its photodiode, but determined that it was centered on all of the in-vac mirrors, and that it was just a little bit of steering on the ETMY end out-of-vac table that needed to be done.

Got green flashes in Yarm, moved down periscope to the north by ~1 inch in order to get y green out to PSL table.  This also involved moving the steering mirror on the IOO table immediately after the down periscope to match.  We measured the MC spot positions before and after touching the periscope, and there was no significant change. 

Aligned X green to X arm (centered on ITMX, ETMX, although no flashes since we didn't move ETMX's biases around), then made sure it was centered on all of its steering mirrors, and came out of the vacuum.

Manasa took photos of all test mass chambers and the BS chamber, so we can keep up-to-date CAD drawings. 

Oplevs and IPPOS/IPANG are being centered as I type.  Manasa and Ayaka are moving the lens in front of IPANG such that we have a slightly larger beam on the QPD.


In the morning, Jamie is going to put apertures back on 2 of the suspended mirrors for one last check that moving things on the IOO table didn't do anything bad, but since the AS and REFL beams on those cameras didn't move significantly, we think things are fine. 

Heavy doors go on in the morning, and access connector at ~1pm, if not before lunch.  Then Steve will start pumping early Monday morning!  Hooray!


PS, for reference,

AS: AS_8Nov2012.png

REFL: REFL_8Nov2012.png

  7699   Tue Nov 13 00:15:08 2012 JenneUpdateIOOInput and Output PZTs turned on

I turned on the power supplies for the output PZTs and pitch and yaw for PZT2.  This is back to the condition that we had during atmosphere alignment, so after Ayaka has finished tweaking the MC, we can have a look at alignment of the interferometer.

  7700   Tue Nov 13 00:19:51 2012 JenneUpdateCamerasITMX is just fine


In other, semi-unrelated news, the ITMXF camera has been not working for a while.  The bottom right quad on the test mass tv has been dark for at least a week or two.  Steve, when you have a chance (after the oplevs are all taken care of), can you see if there's something obvious that's wrong?

 While helping Charles string the ethernet cable (elog 7698) for the power strip in the vertex (from 1Y1 to 1X1), I looked at the ITMX power cord.  It was connected to the same power strip as the illuminator, which, since the illuminator was turned off by turning off the power strip, meant no power was going to the camera.  Since Charles is very close to having the new power strips set up, I unplugged the ITMX illuminator and turned the power strip back on.  ITMX camera is back to normal.

  7701   Tue Nov 13 00:27:50 2012 JenneUpdateElectronicsEthernet Illuminator Control



 The ethernet power strips have been installed. is on ETMX, is on ETMY and is on the vertex. I have also written an EPICS file "illuminator_control.adl" (currently stored in my named directory) that allows a user to turn individual sockets on and off at each of the three locations. Some short tests have indicated that everything is in working order.

Currently, no illuminators are hooked up to the power strips. However, the power control will most likely be ready for use tomorrow, granted I can find and use extension cords so that the illuminators might reach their respective power strips.

 I'm sure Charles meant to also say that he connected the ETM power strips to the ethernet switches in those racks.  For the vertex, the ethernet switch is in 1X2, but there isn't space in there, so the power switch was installed in 1Y2.  The vertex ethernet cable is along the overhead inside cable tray.

I'm not sure what we want to do about connecting the new power strips to the illuminators.  No illuminator is close enough that its built-in cable can reach the power strip, so we'll need extension cables or some such.  Charles is going to ask Steve about the plan tomorrow.

  7709   Tue Nov 13 22:12:15 2012 JenneUpdateIOOTurn off MCL path before doing MC spot measurement

[Jenne, Den]

We have discovered that the MCL loop squishes the length fluctuations that result from the MC spot measurement angular dither.  This is good, in that the MCL is doing what it ought to do.  However, we need to turn it off before doing a spot measurement.

  7710   Wed Nov 14 00:56:19 2012 JenneUpdateIOOWFS on, PZT2 ~set, AS camera back

WFS are back on, and working nicely.  Den and I had seen a problem (which I had seen before) that when you turn on the integrators in the WFS loops, the MC Refl value gets worse (goes up).  Koji reminded me that he had a nice elog (7452) on how to get the MC awesome.  Ayaka and I last night stopped after Step 7.  Step 8, zeroing the WFS offsets, is the secret important thing that I keep forgetting.  I ran the script /opt/rtcds/caltech/c1/scripts/MC/WFS/WFS_FilterBank_offsets, then turned on the WFS loop, and the WFS are working just fine now.   

I'm back to wishing that I had control over PZT1.  I went back and forth for a while between 1Y4 and the ETMY table to get the IPANG beam centered on the QPD.  Initially, the beam was coming out of the vacuum a little high.  The digital HV power supply is pitch, and the analog HV power supply is yaw.  When I get the beam reasonably well centered on IPANG, with a beautiful, non-clipped, beam, the beam is much too high on IPPOS.  The beam barely hits the top of the first out of vac steering mirror, and then is too high on the QPD.  It looks like (based on the sum value) that the beam is on the diode, just entirely in the upper 2 quadrants.  But if I try to fix this, since IPANG has a longer lever arm, the IPANG beam doesn't come out of the vacuum.  I have compromised by getting the beam on IPANG, centered in pitch and ignoring IPPOS pitch.  For yaw, since moving PZT2 only makes one of POS or ANG good at a time, I split the difference, so the beam is not really centered in yaw on either, but it's close on both.

AS beam is back on the camera.  I forgot that, especially since the beam at REFL is pretty bright, I had moved the AS and REFL cameras out of the beam so we didn't crispy-fry the CCDs.  Therefore, the camera spots are no longer a reference of spot position. We can still eyeball the position on, say, the 2" lens, but that's not any kind of accurate.  I put the AS camera back to it's normal place, so the AS beam is going toward AS55 and AS110, and a little bit is going to the camera.  I have not yet aligned the beams actually on to the PDs.

REFL beam is dumped by a razor dump after the 2" lens.  Manasa did some work (elog 7666) to the REFL path, and I'm not 100% sure how it was before, so I leave it to her to please work on during the day tomorrow.  I think we need to put back the Y1 that used to be there, but I don't know where the optic is.  I put a yaw dither on the PRM with awggui, and saw the REFL beam moving at my 2Hz dither frequency, so this time we actually have a useful beam coming out.

  7712   Wed Nov 14 13:58:18 2012 JenneUpdateIOOTurn off MCL path before doing MC spot measurement



We have discovered that the MCL loop squishes the length fluctuations that result from the MC spot measurement angular dither.  This is good, in that the MCL is doing what it ought to do.  However, we need to turn it off before doing a spot measurement.

 This is totally non-sensical statement, of course.

We might also say that the DARM loop totally squishes the GW signal and so its better not to have any feedback in the interferometer.

 Hmmm, indeed.  To keep MC_L on, we should be looking at the control signal rather than the error signal.  I think Den has MC_L running nicely such that it always comes on when the MC locks, so I can switch it.

  7715   Thu Nov 15 03:09:08 2012 JenneUpdateAlignmentNo good progress, many options
I didn't make any concrete progress today. AS and REFL cameras are in place, and Manasa has put ND 0.5 filters on both. I used a 
camera to look at the back of the Faraday, and aligned PRM such that it was retroreflecting, and then tried to align ITMY to have once 
fringes with the PRM at that place. I failed in this, since the AS beam on the AS table was starting to dall off the first mirror on the table. 
I then restored all the suspensions to where they were before I started touching them today. 

I moved ETMY face camera so that it is looking at the front of the black glass, but it's hard to tell where the beam is.  I was thinking 
about setting up a temporary camera to look at the back of ITMY to help guide PZT steering, but I haven't done this yet. 

Koji and I then talked about the several different options I have for references, and how many different knobs I  can turn. I'm sleeping 
on it for now, and hopefully I'll have more insight on what to do tomorrow. 
  7719   Fri Nov 16 09:57:57 2012 JenneUpdateGreen Lockingxarm locked


We aligned and locked xarm for green.


 That's really, really awesome!


  7723   Mon Nov 19 15:12:52 2012 JenneUpdateAlignmentYarm locked IR



POY11 does not go out of the vacuum

 It does but slighty low and does not get on mirrors. We need to change optic mounts to adjust the height. Red is flashing in yarm at 00 and 10 modes. TRY is ~0.4-0.5.

I've adjusted BS angle, camera and TRX PD at ETMX table so I can see red flashing at 03 mode while green is locked to 00 and its transmission is maximized. I thought that by adjusting BS angle, I will be able to align red to 00 not disturbing green, but this was not the case. Maximum TRX I could get was 0.1. I've adjusted POX to get into PD and I can see PDH signal though I can't lock as cavity is still misaligned for red.

 [Ayaka, Jenne]

We put the POY beam onto the POY PD.  The Yarm is currently locked on IR with ~0.65 transmission.


  7724   Mon Nov 19 15:15:22 2012 JenneUpdateSUSAll oplev gains turned on


Oplev values that were changed to zero:

PRM P=0.15, Y=-0.3

SRM P=-2.0, Y=2.0

BS P=0.2, Y=-0.2

ITMY P=2.1, Y=-2.0

ITMX P=1.0, Y=-0.5

ETMX P=-0.2, Y=-0.2

ETMY P=0.5, Y=0.6

Also, PRCL was changed in the LSC input matrix from REFL33I to AS55I, since there is no REFL beam out of the IFO :(

 Ayaka and I restored all of the oplev gains to these values.  The exception is ETMY, which has both gains negative.  I am unsure if this is a transcription error on my part, or if something physical has changed.  The layout of the ETMY oplev was modified (since Rana took out the offending lens) but that shouldn't affect the sign of the gains.

  7727   Mon Nov 19 20:17:53 2012 JenneConfiguration40m UpgradingEndtable upgrade for auxiliary green laser : ETMX layout on new table


For convenience, I would include a steering mirror in front of the TRX PD.  Also, don't we usually have lenses in the oplev paths?  Also, also, do we need lenses in front of the green refl and TRX PDs?  Do you have a place in mind for the shutter?  Is there a way to compactify the layout a little bit, so that even if the lenses are different for each table, the general layout for both ETMX and ETMY is the same (with an empty space on ETMX where IPANG belongs on ETMY)?  I'm sure it is, since you've talked to Steve about this, but just to check: is the green refl PD far enough away from the edge of the table to accommodate the fancy new box?

  7745   Mon Nov 26 18:36:17 2012 JenneUpdatePEMBLRMS back


 I got two seismometers and one microphone back from Tara.

They are now near the Gurlap under the MC.

 I have finally plugged GUR1 back in....it is down at ETMY for now, since that's where the cable was.  BLRMS are back up on the projector.

  7746   Mon Nov 26 18:56:34 2012 JenneHowToComputersData logging suggestions

We've been talking for a while about how we want to store data.  I'm not in love with keeping it on the elog, although I think we should always be able to reference and go back and forth between the elogs and the data.

I have made a new folder: /data    EDIT: nevermind.  I want it to be on the file system just like /users, but I don't know how to do that.  Right now the folder is just on Ottavia. Jamie will help me tomorrow.

In this folder, we will save all of the data which goes into the elog. 

I propose that we should have a common format for the names of the data files, so that we can easily find things.

My proposal is that one begins ones elog regarding the data to be saved, and submit it immediately after putting in the first ~sentence or so. One should then make a new folder inside the data folder with a title "elog#####_Anything_Else_You_Want" Then, data (which was originally saved in ones own users folder) should be copied into the /data/elog#####_AnythingElse/ folder. Also in that folder should be any Matlab scripts used to create the plots that you post in the elog.  One should then edit the elog to continue making a regular, very thorough elog, including the path to the data.  Elog should include all of the information about the measurement, state of the IFO (or whatever you were measuring), etc. 

Riju will be alpha-testing this procedure tonight.  EDIT: nevermind...see previous edit.

  7752   Tue Nov 27 03:26:00 2012 JenneUpdateGeneralPOP beam on POP55, POP camera


Some obvious things to be fixed

-  We need POP55 and POP CCD for diagnoses.

 Done.  The beam is also going vaguely in the direction of POP110, but I can't see the beam, so it's tricky. 

Order of operations:

1. Find POP on the table, place iris so I wouldn't forget.  Find beam by putting big IR card where I think beam should be, look at IR card with IR viewer.

2. Move and re-clamp 2" lens so beam is on center of lens.

3. Move and re-clamp 1st (2") mirror so that beam is on center of mirror. 

4. Remove BS-33% so that all the beam goes to POP55, steer that 1st mirror so beam is on POP55's little mirror.  Align little mirror so beam is centered on POP55 (as seen by looking at PD with viewer, finding "edges" of PD, going back to center).

5. Put BS-33% back in place.  The reflected portion of this beam is not possible to see using card+viewer technique.

6. Remove BS-50% that reflects half of this beam to POP110.  Find beam reflected from BS-33% by waving POP camera around.  Steer BS-33 until beam goes back in the direction that the camera used to be mounted.  Adjust camera mount and BS-33 so that beam is on camera.

7. Put BS-50% back in place.  Steer it around with voltmeter on PD to see if beam ever hits PD.  Unsuccessful. Give up, since we have POP55, and POP camera.

8. Make a youtube video: POP, AS, REFL, ITMXF (all on Quad3) - PRMI coarsely aligned, no IFO parts locked.  MICH was locked earlier, but not during video time.

  7816   Wed Dec 12 16:52:12 2012 JenneUpdateAlignmentPR2_face, PR3_back cameras in place

I have setup cameras looking at the back of PR3 (through the north viewport on the MC chamber) and the face of PR2 (through the north viewport on the ITMX chamber). We would like a view of the face of PR3, but that isn't possible without placing another in-vac mirror.  The best we can do is the current PRM_BS camera setup, which sees a small portion of the PR3 face.  Most of the face is obscured by the PRM itself. 

I have taken images with the PRM misaligned.  The spot near the top of PR2 is the first reflection from the pitch-misaligned PRM, so it should be ignored for the purposes of trying to see the straight-shot, no PRM beam.

Images are taken with my videocapture50 script, in ..../scripts/general/videoscripts.  This takes 10 sets of 50 images and saves them.  Then ImageBkgndSubtractor.m located in the same folder takes the images (you must edit the beginning of the script to tell it where the images are), averages the noBeam images (PSL shutter closed), and averages the withBeam images, and subtracts them.  Results below:



  7828   Fri Dec 14 03:15:49 2012 JenneUpdateSUSTT angle of incidence

But have you looked yet at what angle we need? The first input string mirror has a quite small incidence angle. The other input steering mirror maybe borderline, based on your estimates. Also, have we considered just having new brackets made and cleaned? Is there a reason we would prefer to modify the ones we have?

  7837   Mon Dec 17 11:20:58 2012 JenneUpdateSUSBeam dumps on vertex oplevs removed

I'm not sure when this was done, but there were beam dumps in front of the lasers for BS/PRM oplevs as well as ITMY/SRM oplevs.  MICH wasn't holding lock very nicely, so I poked around, and the Sum values for all of these optics' oplevs seemed too low, so I went to look, and found dumps.  I have removed these, and now BS and ITMY oplevs are back to normal.  (PRM and SRM are still misaligned right now, so I'll check those later, but they should be fine).

BS's oplev has been enabled while non-existant, at least for the whole weekend, since I found it enabled.  ITMY I found misaligned, so it's oplev servos were off.

In other news, we should get back in the habit of restoring all optics before we leave for the night / whenever locking activities are finished. 

  7838   Mon Dec 17 14:13:55 2012 JenneUpdateSUSPRM oplev gains restored


PRM oplev gains set to zero from PIT 0.15 and YAW -0.3 and damping restored

 Put them back to normal.

  7839   Mon Dec 17 14:45:01 2012 JenneUpdateAlignmentVideos with PRMI locked

[Jamie, Jenne]

Koji and Jamie locked the PRMI, and then Jamie and I took some videos. 

Video 1:   https://www.youtube.com/watch?v=jszTeyETyxU shows the face of PR2.

Video 2:   https://www.youtube.com/watch?v=Tfi4I4Q3Mqw shows the back of PR3, the face of PR2, as well as REFL and AS.

Video 3:   https://www.youtube.com/watch?v=bLHNWHAWZBA is the camera looking at the face of PRM and (through a viewing mirror) BS.


If you watch video 1, you'll see how large the beam gets on the face of PR2.  The main spot, where the straight-through, no-cavity beam is, is a little high of center.  The rest of the inflated beam swirls around that point.

Video 2 shows the same behavior, but you also see that we're much too high on PR3, and too close to the right (as seen on the video) side.

Video 3 is very disconcerting to me.  The main, stationary beam spot seems nicely centered, but the resonant beam, since it inflates and gets big, is very close to the right side of the PRM (as seen on the video). 

It wouldn't surprise me if, were we able to quantify the beam clipping loss on PR3 and PRM, the clipping were the reason we have a crappy PRC gain.  This doesn't explain why we have such a weird inflated beam though.

  7840   Mon Dec 17 18:39:02 2012 JenneUpdateIOOIPPOS centered, no IPANG beam

I centered IPPOS.  I do not find any IPANG beam on the ETMY table, even waving the IR card in the black beam tube.

I took photos of the PZT2 HV supplies with the new camera, but I can't figure out how to get the pictures off the camera.  I guess the camera is smarter than I am.

  7850   Tue Dec 18 15:32:29 2012 JenneUpdateSUSTT angle of incidence


At least, we don't want to use Al-coated mirrors. We should use multilayer dielectric mirrors.

 I popped into the cleanroom earlier today, and all 4 active TTs have dielectric coatings.  I'm not sure why the mirror in this photo looks funny, but the actual mirrors installed are correct, at least in type of coating. 

I'm not sure if Den wrote down what mirrors are actually in there, and I didn't look carefully - I don't know if they are G&H, CVI, other mystery company?

  7851   Tue Dec 18 15:51:33 2012 JenneUpdateIOOOld G&H TT mirrors' phase maps measured

I took the 2 G&H mirrors that we de-installed from PR3 and SR3 over to GariLynn to measure their phase maps. Data is in the same place as before, http://www.ligo.caltech.edu/~coreopt/40MCOC/Oct24-2012/ .  Optic "A" is SN 0864, and optic "B" is SN 0884, however I'm not sure which one came from which tip tilt.  It's hard to tell from what photos we have on picasa.

Both are astigmatic, although not lined up with the axes defined by where the arrow marks the HR side.  Both have RoCs of -600 or -700m. RMS of ~10nm.

  7857   Wed Dec 19 18:40:00 2012 JenneUpdateIOOPZT1 removed, TT1 in place

[Manasa, Jamie, Jenne]

PZT1 has been removed, and is wrapped in foil and stored in a (labeled) plastic box.

We beeped the cable between the cable holder bracket on the in-vac table, and the outside of the feedthrough.  Things are mirrored, so pins 1,14 (one edge on the feedthrough) go to pins 13,25 on the in-vac cable bracket.

Tip Tilt, serial number ### (Manasa will get the serial number and put it in the elog) was taken out of the cleanroom, for use as TT1.

We checked the epics controls from the TT screen that Jamie made a while back (accessible from the ASC tab on the sitemap) to the output of the AI board.  Things were very weird, but Jamie fixed them up in the model, then rebuilt and restarted the ASS model so that now the epics channel corresponding to, say, UL actually actuates on the UL output of the boards.

We tested the cables from the rack to the feedthrough, and discovered that they are also mirrored, to undo the mirroring between the feedthrough and the in-vac bracket.

Jamie made an adapter cable to take the pinout of the coil driver boards correctly to the pinout of the quadrupus cable, through this double-mirroring (i.e. no net mirror effect).

We set up a laser pointer on a tripod outside the door of the MC chamber (where the access connector usually is), and pointed it at the back of the TT.  Den or whomever put the cable on the TT didn't follow the diagram (or something got messed up somewhere), because when we actuate in pitch (+ on the uppers, - on the lowers), we see the TT move in yaw, and vice versa. 

We are in the process of removing the quadrupus from the TT, figuring out which connector goes where, putting it on correctly, and re-testing.

Depending on how far things get tonight, Jamie and Manasa may ask Steve to help them remove the BS door, so they can get started on replacing PZT2 with TT2.

  7872   Wed Jan 2 15:33:23 2013 JenneHowToLockingWe should retry in-air locking

Immediate things to do include finishing installation of new TTs and re-routing of oplev paths in the BS chamber, but after all that, we should retry in-air locking.

The last time we (I) tried in-air locking, MICH wouldn't lock since there was only ~ 6uW of light on AS55 (see elog 7355).  That was before we increased the power into the MC by a factor of 10 (see elog 7410), so we should have tens of microwatts on the PD now.  At that time, we could barely see some PDH signal hidden in the noise of the PD, so with a factor of 10 optical gain, we should be able to lock MICH.

REFL should also have plenty of power - about 1.5 times the power incident on the PRM, so we should be able to lock PRCL. 

Even if we put a flat G&H mirror after the PRM to make a mini-cavity, and we lose power due to poor mode matching, we'll still have plenty of power at the REFL port to lock the mini-cavity.

For reference, I calculate that at full power, POX and POY see ~13uW when the arms are locked.


POX/POY power =  [  (P_inc on ITM) + (P_circ in arm)*(T_itm)  ] * (pickoff fraction of ITM ~ 100ppm)

REFL power = (P_inc on PRM) + (P_circ in PRCL)*(T_prm)     =~ 1.5*(P_inc on PRM)

  7876   Fri Jan 4 15:11:28 2013 JenneUpdate TT

[Jenne, Koji]

D - UL

B - UR

A - LR

C - LL

The sensor card on the bottom of the chamber was not salvaged yet.

  7877   Mon Jan 7 00:08:16 2013 JenneHowToAlignmentIn-vac plan

List of things to do, in order:

* Remove BS heavy door.  Steve, please remove the BS door as soon as you have enough people to do so.  I will be a little late, since I have a dentist appointment, but please don't wait for me.  Jamie and Manasa can help you.  Put on a light door.

* Remove MC light doors, make aluminum foil tube (not light access connector, yet).

* Open laser shutter, lock PMC. (Required slight tweaking of input steering.) Confirm power level into vacuum <100mW.

* Lock MC and check spot positions of MC (quickly.  this shouldn't take all day, hopefully).

-------------------------------  End of work for Monday.  See following elog ------------------------------------------------


* Move TT1 to be as close as possible to the location indicated on the diagram, then align it. 

         * Make sure beam out of Faraday is hitting the center of the optic.

         * Make sure beam reflected off of TT1 hits center of PZT2.  Only use actuators for the final alignment, then confirm that they aren't close to the edge of their ranges.

         * Lock down TT1 with dog clamps.

* Put light access connector on MC.

* Swap PZT2 out with TT2.  Should be at correct spot, according to diagram, and beam should be hitting center of optic.  Alignment only to the ~few degree point here.

* Re-level BS table.

* Fix oplevs that need fixing.  (Manasa should have the plan on one of the diagrams).

* Put target on PRM cage.

* Align TT2 so that beam goes through PRM target.

* Open ITMX heavy door. (Probably Tuesday morning).

* Place freestanding target in front of PR2.  Ensure TT2 is aligned to go through PRM target, and hit center of PR2.  Again, save actuators for fine-tuning.

At this point, I think we should (temporarily) install one of the G&H mirrors as a flat mirror facing the PRM, and see if we can lock that cavity using REFL.  We will want to have already created a model for this case, to compare our observations to.  Or we could align the full PRMI, and try to lock that in air.



  7878   Mon Jan 7 16:45:30 2013 JenneUpdateAlignmentRisers to bring TTs to correct beam height are wrong

[Jenne, with backup from Koji and Steve]

Short version:

TT1 was installed without a riser, optic is too low, riser we have doesn't fit, cannot proceed with alignment.  Sadface.

Long version:

I had gotten to the point of checking that the beam coming out of the Faraday was hitting the center of TT1, when I realized that we had forgotten to install the risers.  The TTs are designed for 4" beam height, but we have a beam height of 5.5" in-vac.  This means that the beam out of the Faraday was hitting the top of the optic / the optic holder.

Steve showed me where all of the active TT equipment is stored (down the X arm, almost all the way to the flow bench...there is a plastic tub full of baked items (individually wrapped and bagged)), and I got one of the 1.5" risers.

Upon opening the riser package, and comparing it with the base plate of the active tip tilt, the screw holes don't match!


It looks like for the passive tip tilts, we had holes machined at the far corners of the base plate, then had these risers made.  You can see in the photo of SR3 below that the original holes are there, but we are using 1/4-20 holes at the far corners of the base plate.


Unfortunately, without checking the base plate, I had asked Steve to get 4 more of the same risers we used for the passive tip tilts.  So, now the base plate holes and the riser holes don't match up.  In a perfect world, we would have installed the risers on the TTs as soon as they were baked and ready, and would have discovered this a while ago....but we don't live in that world.

 The reason we had originally chosen to put the new 1/4-20 holes on the corners of the passive tip tilts was so that when we tightened the screws, we wouldn't bend the base plate, due to the groove at the bottom of the base plate being directly under the screws.  Since the new aLIGO TT base plates have the groove underneath going the opposite direction, we didn't need to move the holes to the corners.

Also, you can't really see this from the photos, but the active TT base plate is slightly longer (in the beamline direction) than the riser, but only by a little bit.  Koji is currently trying to measure by how much from the CAD drawings.

Also, also, because of the way TT1 will hang off the table, I'm concerned about the underneath groove on the riser being the direction it is.  I'm concerned that the grooved part will be what wants to touch down on the back corner of the table, such that either the TT is insufficiently supported, or it is tilting backwards.  Neither of these will be acceptable.

I propose that we re-make the risers quickly.  We will have the holes match the active TT base plate, the size of the riser should match the size of the active TT base plate, and the underneath groove should be perpendicular to the way it is in the current version.

  7883   Tue Jan 8 17:54:34 2013 JenneUpdateAlignmentRisers to bring TTs to correct beam height are in use


 [Jenne, EricQ, Nic, MattA]

* TT1 is in place, aligned so beam hits center of TT1, hits center of MMT1 (used pitch biases to finish pitch).

      * Riser installed, dogged down with 1 dog.

      * TT1 sitting on top of riser, 3 dogs holding TT to table, with riser squished in between.

* IOO table leveled.

      * Almost all of the weights on the IOO table were just sitting there, not screwed down!  One didn't even have a screw, 3 had screws, but they were totally loose.  2 of those screws were in as far as they could go, but they weren't holding the weight.  This means the screw was too long, and should have been replaced (which I did today).  Just because the existing screw was too long, doesn't mean it should be left as-is.  Everything in the chambers must be tightly clamped down, as soon as work on that item is complete!  Anyhow, after finalizing the leveling, I tightened down all of the weights on the IOO table.

* MMT1 tweaked so beam hits center of MMT2. 

* MMT2 tweaked so beam hits center of PZT2.

* Light access connector installed.


Sadface notes:

* I dropped a Class B golden-colored 3/16 allen key to the bottom of the IOO chamber.  I can't see it, but Nic thinks he might be able to see it with a mirror, from the BS chamber.  We should look for it when we look for the IR card that is still down there.

* We have an ant in the IOO chamber.  Unfortunately my hands were on the TT1 optic holder ring when I saw it, so I couldn't dash quickly enough to grab it.  I saw it run over the side of the table, and down, but looked under the table and couldn't find him.  Not so good, but I don't know what to do about it right now.  If anyone sees it, get it out please.

  7884   Tue Jan 8 18:10:41 2013 JenneUpdateSUSPRM, SRM, BS oplevs off

I don't know why (I'm just leaving the lab right now....) but BS, PRM, SRM all have no light on their oplev PDs. I have turned off the oplev servos for now, and will get back to them tomorrow, before redoing the BS table oplev layout.

  7886   Wed Jan 9 18:59:01 2013 JenneUpdateAlignmentTT2 installed, PRM oplev layout changed

[Jenne, Manasa]

PZT2 was removed from the BS table, and packed away in a foil-lined plastic box.

PRM oplev path has been altered, including installation of a 3rd mirror, to accommodate TT2, which is larger than PZT2.

      * Unfortunately, PR3 is a few mm more north than is indicated in the CAD drawing, so I wasn't able to place the oplev mirrors exactly as Manasa indicated in elog 7815

      * We came up with a different layout. Photos were taken.  We will need to confirm that the IPPOS, AS, and GreenX beams all clear past the oplev mirrors, but by imagining straight lines between mirrors for those beams, I think we should be okay.  but we must confirm when we have real beams.

TT2 was installed, according to the placement in the diagram.   Dogged down just as TT1 - one dog for the riser, 3 dogs for the TT base which also squish the riser.  You should be able to see this in the photos. Without having installed the PRM target, it looks like the input beam is hitting pretty close to the PRM's center.  Tomorrow Jamie The Tall can install the PRM target for us so we can confirm.


Photos - I'm posting them on Picasa here.  The new camera, and the fact that you can rotate the viewfinder, is amazing for overhead in-chamber photos.  Seriously, it's much easier to take useful photos.  It's great.



We remove the ITMX door first thing.  If Steve isn't here, we'll ask Koji or Bob to help us with the crane. 

First thing on the alignment list is to finalize TT2's pointing.  Put a target in front of PR2, put on the PRM target, etc, etc.  We're basically back to the same alignment procedure as we've been doing the last few vents.


Item for meditation:

Do we trust ourselves, or do we want to think about installing a 'bathroom mirror' so we can see the face of PR3 while we are pumped down?

  7888   Thu Jan 10 12:22:36 2013 JenneUpdateAlignmentTT matrix is funny


* TT1 is in place, aligned so beam hits center of TT1, hits center of MMT1 (used pitch biases to finish pitch).

 I had asked Q to write this down on a piece of paper, but then I forgot to transcribe it into the elog....

The TT screen matrix, at least for TT1, is flipped or something.  When Eric moved the pit slider, the optic moved in yaw, and vice versa. 

We need to fix this, but for now, here's the situation when TT1 was pointed correctly at MMT1:

                       PIT    YAW

TT1 Pit slider     |  1000   1000  | --->   700 UL

     0             | -1000   1000  | --->   700 LL

TT1 Yaw slider     |  1000  -1000  | --->  -700 UR

    0.7            | -1000  -1000  | --->  -700 LR


The confusing thing is that Koji and I confirmed (by plugging in the correct cable to the correct sensor) that "UL" on the screen goes to the UL coil, and the same for the other 3 coils.  This needs investigation / fixing.

  7890   Thu Jan 10 15:30:33 2013 JenneUpdateAlignmentTT2 pins swapped, ITMX door open


[Bob, Manasa, Jenne]

We opened the ITMX heavy door.  Before getting too far, we realized that we had to do the fancy pin swapping before we can activate TT2.  So....

[Nic, Jenne]

We followed the instructions in elog 7869, and the associated Picasa album, and swapped the pins for the in-vac connector that will go to TT2.  Pretty easy, since the procedure was already well documented.

We then looked at the beam location on PR2, and the beam is ~2 inches up and to the left (as viewed from the front) from the center of the optic.  This is very easily correctable with the actuators, so we're leaving TT2 as it is.

  7892   Fri Jan 11 16:13:47 2013 JenneUpdateGeneralIFO status update - PMC fixed


I came in this morning to see that the PMC was down. The PZT voltage had drifted to below 50V. I adjusted the FSS slow controls to 0V and PZT was back at 126V.

PMC and IMC could eventually be locked.

History of PZT voltage behaviour in dataviewer over the last 24 hours shows it has been drifting everytime after it has been fixed.

 FSS was saturating.  Fixed.

  7896   Mon Jan 14 10:12:09 2013 JenneUpdateAlignmentTT2 connections


Was the connection between the feedthrough (atmosphere side) and the connector on the optical table confirmed to be OK?

We had a similar situation for the TT1. We found that we were using the wrong feedthrough connector (see TT1 elog).

 The major problem that Manasa and I found was that we weren't getting voltage along the cable between the rack and the chamber (all out-of-vac stuff).  We used a function generator to put voltage across 2 pins, then a DMM to try to measure that voltage on the other end of the cable.  No go.  Jamie and I will look at it again today.

ELOG V3.1.3-