More of the same.
Who is putting weird figures into the elog?!?! I haven't checked lately, but this is what usually crashes the elog. It's been happening a lot lately, and it might be the .pdf's.
Let's play a new game. We'll call this game "Everyone only use .png files for the next week" Ready? GO!
We characterized Tip Tilts numbers 2 & 3 today. Recall #4 is the one which Koji and I measured some time ago, and #s 1 & 5 have yet to be suspended (that's on the to-do list for tomorrow).
When we began looking at #3 (the one which had been in the BS chamber for a few days, but was removed for characterization) we found that the pitch pointing was way off. The beam was way too low after reflection. So we adjusted that (and got it right on the first try....a miracle!). This does however make me pretty concerned about our in-chamber pointing. Are we destroying our pointing during travel between the cleanroom and the chambers? Is there anything we can do about it? Pointing doesn't seem to be lost when we move them around on the tables in the cleanroom, ie we can pick up a TT, move it, leave it for a while, move it back to the oplev, and the pointing still seems okay. But the TT which was sent to the chambers came back with bad pointing. I'm sure this is related to the hysteresis we see in the pointing if we poke the top of the mirror holder versus the bottom when exciting pitch motion.
For both #2 and #3, we measured the frequency and Q of Pitch, Yaw, Pos, Side, Vert motion. For the Vert motion, we measured both without and with EQ stops as dampers. For the other modes, all were measured with the ECD backplane in place. Pitch and Yaw were measured with reflection off of the mirror surface onto the PD, while Pos, Side and Vert were measured using the wire clamp on the mirror holder to obscure the beam as a shadow sensor.
Pitch: Overdamped, no freq measured, Q < 1/2
Yaw: freq ~1.8Hz, Q between 2-7
Pos: freq ~1.75Hz, Q too low to measure, but above critically damped
Side: freq ~ 1.8Hz, Q~5
Vert no dampers: freq ~20Hz, Q~36
Vert with dampers on outer screws: freq~24Hz, Q~8,
Pitch: no freq measured. Q~1/2? Upon being excited in Pitch, the beam started down way below the photodiode, came up a little past its DC place, and went back down a tiny bit. So not quite overdamped.
Yaw: freq ~1.96Hz, Q very low
Pos: freq ~1.72Hz, Q~3
Side: freq ~1.85Hz, Q~6
Vert no dampers: freq ~20Hz, Q~75
Vert with dampers on outer screws: freq ~20Hz, Q~34 (Frequency stayed constant....we did several measurements both with and without the dampers...but the half life time changed significantly)
Things we noticed: Koji and I had been concerned the last time we were looking at TT#2 because the frequency got lower and the Q seemed to get higher when we added the damping to the vertical blades. Yoichi and I did not find that to be true today. We did notice, however, that the EQ stop screws with the viton had been placed in the holes closer to the clamping point, whereas with TT #4 the screws had been placed in the holes farther from the clamping point. We moved the screws on TT #2 to the outer holes, and noticed that the frequency increased slightly, and the Q significantly decreased. We then followed this outer-hole philosophy when installing screws in TT #3.
To Do List: We need to suspend the ECDs and the Optics for the remaining two Tip Tilts, and to characterize them. We also (probably farther-future) need to take transfer functions using a shaker / shake table with our spare Tip Tilt. After all the TTs are suspended and have their modes measured, we will be ready for installation into the chamber during the next vent.
The elog was so dead this time that the restart script didn't work. I followed the restart-by-hand instructions instead, with success.
The final 2 Tip Tilts (#1 and #5) have been suspended. We have designated #5 the spare. It looks like there might be a teensy bit of dust on the AR surface of the optic in #5, right near the edge of the coating. Not a critical issue if this one is the spare, although we should see if we can blow it off with the Nitrogen. Both #1 and #5's optics were suspended using the thicker wire, 0.0036" diameter. This leaves 4/5 TTs with this thick wire, and 1 of the 5 has the thin wire.
To do still: Balance both #1 and #5, and then measure the modes of each. Then we'll be ready to install them into the chambers, and we'll reserve #5 for shake table TFs for some later date.
Just for added interest, I tried a different method when the restart script broke. The "start-elog-nodus" script has a line "kill elogd". This seems not to be actually killing anything anymore, which means the elog can't restart. So this time I went for "kill <pid number>", and then ran the startup script. This worked. So it's the "kill elogd" which isn't working reliably.
Hooray!!! The Tip Tilts are completely done! The only things remaining are (1) Install 4 TTs in chambers sometime in September and (2) do shake tests / take TFs of the spare.
Today we balanced and characterized #'s 1 and 5. All 5 TTs are waiting happily on the flow bench in the cleanroom for installation.
Bad CDS team. Bad.
Thoughts on where to take the pickoff for the SHG for the PSL-green? We discussed today at the meeting the possibility of putting a 90/10 beam splitter right after the PMC, so that the green team would get somewhere between 100-200mW.
I think op540m has finally bitten the dust. I noticed that both of its screens were black, so I assumed that it had crashed due to known graphics card issues or something. But upon closer inspection, it is way more dead than that. I checked that it does have power (at least the power cable is securely plugged in at both ends, and the power strip its on is successfully powering several other computers), but I can't make any lights or anything come on by pressing the power button on the front of the computer tower.
Immediate consequences of op540 not being operational are the lack of DMT, and the lack of Alarms.
Joe is doing an autopsy right now to see if its really dead, or only 'mostly dead'.
EDIT: Joe says maybe it's the power supply for the computer. But he can't turn it on either.
Like a new phoenix, the 40m PSL is in the process of being reborn...
We cleared many old optics and components (including Alberto's favorite periscope) off of the north end of the PSL table. Some optics are stored on the SP table, others on the shelf inside the PSL enclosure.
The new Innolight 2W NPRO is on the table, the PMC has been moved, and the main path of the laser has been sketched out using steering mirrors. Since we still don't have a beam, we're roughly placing all of our optics, and we'll finalize the alignment after turning on the laser.
Using a leveled HeNe, I checked the height of optics we should use to match the height of optics in the chambers by shining the light at the first steering mirror in the chamber, and ensuring that the beam hit the center of that optic . Since the new PSL table height is identical to the AP table, it's not a surprise that from now on we will be using a 4" beam height on the PSL table, rather than the old PSL 3" beam height.
On the to-do list is to make a plate with 4 through holes to raise the PMC up by 1 inch, and to make an adapter plate (or come up with another plan) for mounting the AOM that goes directly after the NPRO/Faraday, among many other things. We also still need to make some space for the RefCav to be put in its new place on the table, and then install it with Steve's help.
As it turns out, data seems to fall off the 16Tb drives after ~20 days. Which makes it a good thing that I saved all of my raw data from my good Mode Cleaner / seismic weekend for offline Wiener Filtering in the following secret place:
It's not linked to the svn, since it's a boatload of data.
More PSL progress.
The new laser was raised to a 4 inch beam height using basically the most randomly thrown together method possible. (It'll work just fine for aligning things, but we seriously need to get a nice block made.) The PMC and the nice Osamu-mirror mount to go into the PMC also have temporary risers, so we'll need to replace them with the real deal as soon as we get things back from the shop.
So far we've got (1) the lens after the laser, (2) a Half Wave Plate (no quarter wave plate yet), (3) steering mirror that will go after the EOM, (4) 2 steering mirrors to get into the PMC, in addition to all of the stuff that we did the other day. With all of this stuff we've got the beam hitting the 1st PMC mirror. We still don't have the EOM and AOM in the beam path however.
To get the rough alignment that we did, we turned on the new 2W NPRO, operating at the minimum power we could see on a card. We turned it off after use, so it is still off. Steve, we left the cable for the interlock sitting on the PSL table on the NW corner....can you please hook it up tomorrow? Also, after the interlock is installed we should go back to regular running laser hazard mode.
This totally creeped me out when I found it wandering around on the floor not so far from my desk:
Rana and I were poking around on the PSL table today, getting a few more items raised to the correct height.
I checked the polarization state of the new NPRO by using a HWP to minimize the transmission through a PBS cube, and then compared the power transmitted through the cube vs. reflected. When the NPRO current was 0.772 \pm 0.001 (as read on the LCD), the transmission through the cube was 1.44mW, while the reflected was 10.53mW. The reading of the Ophir power meter with no incident light was 0.03mW. This factor of 10 means that the NPRO beam is ~10% circularly polarized and ~90% linearly polarized. In order to improve the beam, we need a Quarter Wave Plate, which it turns out we don't have. We need a QWP!
After that, using the linearly polarized part of my beam (maximizing the transmission through the PBS by rotating my HWP by 45deg), I tried to tune the angle of the polarizers that Rana pulled out of the MOPA. I think I'm confused / too tired, because I can only get the polarizer to reflect a bunch of light, and I can't get it to pass any significant amount of light through, no matter where in its actuation range I put it (It's on a rotation stage with a few degrees of range). It should just be a Brewster's Angle thing, and since I already have P-pol coming through the BS cube, this shouldn't be so hard.....
In any case, it may not be useful to do the final fine tuning of these polarizers until they are in their final places. The hacky stack of mounts that I have has some slop in the position / alignment of the base of the polarizer, so no matter what we'll have to redo the tuning after the mounts are finalized.
On the one hand, SHAME ON ALL PEOPLE WHO DON'T ELOG THINGS, such as the moving of scripts directories (it was a pain to figure out that that's part of why the backup scripts are broken). On the other hand, the moving of the scripts directories brought to light a critical problem in the backup scheme. None of the frame files have been backed up since Joe replaced fb40m with fb, on ~23 Sept (I think).
What went down:
The frame builder was replaced, and no backup script was started up on the new machine. Sadface. Crontab doesn't work yet on the new machine, and also the 'ssh-add' commands give an error:
controls@fb /cvs/cds/rtcds/caltech/c1/scripts/backup $ ssh-add ~/.ssh/id_rsa
No such file or directory
controls@fb /cvs/cds/rtcds/caltech/c1/scripts/backup $ ssh-add ~/.ssh/backup2PB
No such file or directory
Thus, I know that the backup was never running on the new fb. However, the check-er script runs on nodus, and looks at the logfile, and since there was no script running, it wasn't adding to the log file, so the last log was an "Okay, everything worked" entry. So, the check-er script kept sending me daily emails saying that everything was okie-dokey.
Since all of the scripts were moved (Joe said this happened on Friday, although there's no elog about it), the check-er script, and all of the rest of the backup scripts point to the wrong places (the old scripts/backup directory), so I didn't receive any emails about the backup either way (usually it at least sends a "Hey, I'm broken" email). This clued me in that we need to check things out, and I discovered that it's all gone to hell.
Since I can't add the ssh clients to the new fb, I can't actually log in to the backup computers over in Powell-Booth to check when the last legitimately successful backup was. But I suspect it was just before the fb was replaced.
So, we need to get Crontab up and running on the new Frame Builder machine so that we can run cron jobs, and we also need to figure out this backup hullabaloo. I think I'll email / call Dan Kozak over in downs, who was talking about upgrading our backup scheme anyway.
We've put the old PRM and SRM (which were living in a foil house on the cleanroom optical table) into Steve's nifty storage containers. Also, we removed the SRM which was suspended, and stored it in a nifty container. All 3 of these optics are currently sitting on one of the cleanroom optical tables. This is fine for temporary storage, but we will need to find another place for them to live permanently. The etched names of the 3 optics are facing out, so that you can read them without picking them up. I forgot to note the serial numbers of the optics we've got stored, but the old optics are labeled XRM ###, whereas the new optics are labeled XRMU ###.
Koji chose for us PRMU 002, out of the set which we recently received from ATF, to be the new PRM. Suresh and I drag wiped both sides with Acetone and Iso, and it is currently sitting on one of the rings, in the foil house on the cleanroom optical table.
We are now ready to begin the guiderod gluing process (later tonight or tomorrow).
We've aligned the guiderod and wire standoff to the PRM, each partly. They have both been aligned to the correct distance above the scribe lines, but they have not yet been centered forward/backward along the thickness of the optic. So, we're working on it...
This afternoon I epoxied the guiderod and wire standoff to the new PRM. I also epoxied the magnets that Suresh picked out to the dumbbell standoffs. We'll let them all cure over the weekend, and then I'll glue the magnets to the optic on ~Monday.
Notes about the epoxy:
Previously, we had been using the "AN-1" epoxy, which is gray, with a clear hardener. Bob recommended we switch to "30-2", which is clear with clear, and has been chosen for use in aLIGO. Both were vacuum approved, but the 30-2 has gone through ~2 months of testing at the OTF (Optics Test Facility?) over in Downs under vacuum, to check the level of outgassing (or really, non-outgassing).
The 30-2 is less viscous than the AN-1, and it takes less glue to do the same job, so we should keep that in mind when applying the epoxy. When I put the glue next to the guiderod and standoff, it got wicked along the length of each rod, which is good. I can't reach the whole length of the rod with my glue applicator because the fixture holding them in place blocks access, so the wicking is pretty handy.
I've also added the updated version of my Status Table for the suspensions.
As the suspension work winds down (we'll be completely done once the ETMs arrive, are suspended, and then are placed in the chambers), I'm going to start working on the RF system.
Step 1: Figure out what Alberto has been up to the last few months.
Step 2: Figure out what still needs doing.
Step 3: Complete all the items listed out in step 2.
Step 4: Make sure it all works.
Right now I'm just starting steps 1 & 2. I've made myself a handy-dandy wiki checklist: RF Checklist. Hopefully all of the bits and pieces that need doing will be put here, and then I can start checking them off. Suggestions and additions to the list are welcome.
[Jenne, Suresh, Thanh (Bram's Grad Student)]
When we removed the grippers from the magnets on the PRM, one of the face magnets broke off. This time, the dumbbell remained glued to the optic, while the magnet came off. (Usually the magnet and dumbbell will stay attached, and both come off together). I had 3 spare magnet-dumbbells, but only one of them was the correct polarization. The strength of the spare magnet was ~128 Gauss, while the other magnets glued to the PRM are all ~180 Gauss. We considered this too large a discrepancy, and so elected to reuse the same magnet as before.
We removed the dumbbell from the optic using acetone. After the epoxy was gently removed, we drag wiped the AR face of the optic (Acetone followed by Iso, as usual), being careful to keep all the solvent away from all the other glue joints. We cleaned off the magnet with acetone (it didn't really have any glue stuck on it...most of the glue was stuck on the dumbbell), and epoxied it to a new dumbbell.
The PRM, as well as the magnet-dumbbell gluing fixture are in the little foil house, waiting for tomorrow's activities. Tomorrow we will re-glue this magnet to the optic, and Thursday we will balance the optic.
This still leaves us right on schedule for giving the PRM to Bob on Friday at lunchtime, so it can bake over the weekend.
Since MC2_TRANS is, in fact, MC2 Transmission, and not an oplev at all (it's not red, and it's not a lever, although it does use a QPD), I propose that the name be changed to something sensical, since calling it an oplev is completely non-sensical. The name change should happen sooner rather than later, to avoid confusion.
Today, we fixed OPLEV stuff, MCL filters, and time stamps.
What we did:
5. Checked OPLEV for MC2 by pointing a laser pointer to QPD. (For MC2, OPLEV is just a transmission beam position monitor)
Each quadrant looked like they are connected to the right channel numbers.
DTT has only SUS and "X02" channels under C1 in the drop down channel selection menu. Basically, we can't measure any fast channels with DTT. I keep getting the error: "Unable to select testpoints." Sadface.
Similar things are true for DataViewer. The same limited number of fast channels, and no data found:
Server error 13: no data found
datasrv: DataWriteRealtime failed: daq_send: Illegal seek
Is this a framebuilder problem? Is this something that the CDS team has on the to-do list?
We took a look-see at the PRM after the gluing from last night. The balance is still okay. The reflected beam is a teeny bit below the laser aperture (center of the beam maybe ~2mm below, so ~1mRad low). This is within our okay range, since the DC offset that the OSEMs will give will be even more, and the coils can definitely handle this kind of offset.
We took the optic out of the tower, and gave it to Bob and Daphen to bake over the weekend.
At Koji's request, we disassembled 2 of the old Green suspension towers that have been sitting along the X-arm forever (read that last word in a 'Sandlot' voice. Then you'll know how long the suspensions have been sitting there).
They are now hanging out in plastic trays, covered with foil. They will now be much easier to store.
We should remember that we have these, particularly because the tables at the top are really nice, and have lots of degrees of freedom of fine adjustment.
Atm1, there is one more of these old suspension towers
Over the weekend, Bob and Daphen gave the PRM a 48hr. vacuum bake. This afternoon Suresh and I placed it back in the wire in the tower. We used the microscope-on-translation-stage technique to make sure the scribe lines on each side of the optic are at the same height, and then secured the PRM using all of the EQ stops. It is wrapped in foil, and ready for its journey into the IFO room. When we next have the BS chamber open, we should put the PRM in, and move the current PRM to its final place on the ITMY table as the SRM.
Dear whomever setup the camera on the SW corner of the PSL table,
It would be handy if, even for temporary setups, all cables went underneath the white frame around the PSL table. As it is now, the cables are in the way of the door. The door is pretty much closed all the way, but if someone were to open other doors, the far door can easily be pushed all the way to the end of the track, thus squishing the cables. Squished cables are bad cables.
Joon Ho and I took a look at the RF stuff that Alberto left, and we determined that we've got most everything that we need. On Monday, Joon Ho will list off the stuff that we're missing, and we'll have Steve order it.
Joon Ho also replaced the temporary front panel to the RF generation box with Alberto's fancy new panel. Pics are here (although you have to sign in as foteee to see them).
Work on the frequency distribution box will continue on Monday.
We have put together the new-old ETM towers. These are the ones which were hanging out on the flow bench down the arm for years and years, and have recently been re-baked. Interestingly, these are predominantly steel, whereas the newer ones are mostly aluminum. This caused momentary drama while we scrounged for the correct screws (we needed more silver-plated screws than anticipated, since we were screwing into steel and not aluminum), however the miscellaneous clean hardware collection came to the rescue. We did however use up all of the 1/4-20 3/4" silver plated screws, so hopefully no one else needs more later...
We only found 5 (enough for one of the two towers) spring plungers which are used to hold the OSEMs in place. Suresh is sending an email to Steve to ask him to buy some more, so we can get them cleaned in time for use. This is important, but not super urgent, since we have ~ 2 weeks before the ETMs will be ready for installation.
Koji has not yet had a chance to inspect the ETM data sheets and choose for us which pair of ETMs to use (ATF sent the 4 ETMs in matched pairs). So we will not begin the "arts and crafts" until tomorrow-ish.
We pondered the idea of clamping the PRM optic to measure the OSEM noise. So we opened up the BS tank to give this a try. We rediscovered that Jenne is too short to reach the other side of the PRM tower, so we couldn't fully clamp the optic (when is Jaime coming again? He's kind of tall...) If we only did the back 2 EQ stops, the optic would still be able to rock, and thus defeat the purpose of clamping anyway. So we didn't go for it.
While we were in there we saw that the SRM OSEMs were just hanging out on the table, and decided to go with them. See Valera's elog for details on our measurement. We closed up the tank without making any changes to anything.
In other news, we still need to figure out how to change up the connectors to get those OSEMs over to the ITM table. This needs to happen pretty soonish.
[Steve, Jenne, Suresh, Koji]
The remaining test mass chambers have been opened, and have light doors in place. Now we can do all of the rest of the IFO alignment, and then (hopefully) button up before the New Year.
Today has been a downright miserable day in the world of suspension work. Thumbs down to that:
Yesterday, we had glued 2 full sets of magnets to dumbbells. Today, half of those broke. I think I put too thin of a layer of glue on the magnets when gluing them to the dumbbells. All magnet/dumbbell assemblies should pass the test of being picked up by the dumbbell while the magnet is stuck to the optical table or a razor blade. 6 of the 12 magnets failed this test. Suresh soaked the dumbbells that had been used in acetone, and scrubbed them, so we can reuse them when we reglue things tomorrow. By some miracle, we have exactly one full set intact (for each set of 6, we need 4 of one direction and 2 of the other). This was frustrating, but not yet a deal-breaker. That part comes next....
I got ETMU05 nicely aligned in the magnet gluing fixture, and then was on my last check of whether the side magnets would be glued in the correct place when I realized that the fixture is all wrong for the ETMs. This final check was added to the procedure after the drama with the ITMs of having the side magnets glued incorrectly as a result of the fixture being specific to the wedge angle of the optic. Kiwamu and I had set the fixture to be just right for the ~1deg wedge corner station optics, but the ETMs have a 2.35deg wedge (according to the Coastline spec sheet, which is consistent with our measurements when placing the guiderod and standoffs). Suresh and I need to reset the height of the optic in the fixture using more teflon sheets, but we don't have a whole lot of options ready in the cleanroom. We're going to cut some more pieces and ask Bob to clean them tomorrow. Since the way the fixture holds the teflon is a little hoaky, Suresh suggested just resting the optic on teflon pads, rather than screwing the teflon to the fixture, and then putting the optic on the pads. We'll try Suresh's method tomorrow, and hopefully it will be pretty easy.
At least the guiderods and standoffs were successfully glued to the optics....
Here's the updated Status Table. I don't think we're going to be able to have an ETM ready for the chambers early next week, but we should still be able to have both ready for the Monday after Thanksgiving. The spring plungers arrived today, and were given immediately to Bob and Daphen for cleaning.
Suresh and I glued the intact-from-the-first-round magnets to ETMU05. I accidentally got too much glue on one of the dumbbells (the glue was connecting the dumbbell to the gripper - bad news if we let that dry), and while I was cleaning it, the magnet broke off. So I used one of the ones that Suresh had re-glued last night, and he is putting that one back together after some cleaning.
To set the fixture, Suresh had the great idea of using small pieces of foil underneath the teflon pads to set the height of the optic in the fixture. The optic still rests on the teflon pads, but with the foil we have finer control over how the optic sits. Neat. Since both ETMs are the same, we shouldn't have to do any more adjustment for the other ETM.
The updated Status Table:
A story about minor disasters, and crises averted:
Once upon a time, in a cleanroom not so far away..... there lived an optic. To preserve anonymity, we shall call him "ETMU05". This optic had a rough day. When removing the grippers from the magnet-to-optic fixture, 4 out of 6 magnets broke off the dumbbells (the dumbbells were still securely glued to the optic...these had come out of the same batch that had problems last week, same problem). The remaining 2, LL and LR, were sadly of the same polarity. This is bad, because it means that the "humans" taking care of "ETMU05" didn't check the polarity of the face magnets properly, and ensure that they were laid out in an every-other pattern (LL and UR having the same polarity, and LR and UL having the opposite). So, the humans removed all magnets and dumbbells from ETMU05. All remaining glue was carefully scrubbed off the surfaces of ETMU05 using lens paper and acetone, and the magnets and dumbbells were sonicated in acetone, scrubbed with a lint-free wipe, sonicated again, and then scrubbed again to remove the glue. ETMU05 had a nice cleansing, and was drag wiped on both the AR and HR surfaces with acetone and iso. ETMU05 is now on vacation in a nice little foil hut.
His friend, (let's call him ETMU07) had a set of magnets (with polarities carefully confirmed) glued to him. The cleaned magnets and dumbbells removed from ETMU05 were reglued to their dumbbells, and should be dry by tomorrow.
.....And then they lived happily ever after. The End.
The revised schedule / status table:
Joe showed me what was what with adding DAQ channels, and I have begun building a simulink model to acquire the PEM channels.
My models is in: /cvs/cds/rtcds/caltech/c1/core/advLigoRTS/src/epics/simLink/c1pem.mdl
Next on the to do list in this category: test which input connector goes with which channel (hopefully it's linear, exactly as one would think), and give the channels appropriate names.
ETMU07 had its wire winched to the correct height, was balanced, standoff glued. Can be ready for going into the oven tomorrow, if an oven is available. (One of Bob's ovens has a leak, so he's down an oven, which puts everything behind schedule. We may not be able to get anything into the oven until Monday).
ETMU05 had magnets glued to the optic. Hopefully tomorrow we will winch the wire and balance the optic, and glue the standoff, and be ready to go into the oven on Monday.
The spring plungers were sonicated, but have not yet been baked. I told Daphen that we'd like the optics baked first, so that we can get ETMX in the chamber ASAP, and then the spring plungers as soon as possible so that we can install ETMY and put the OSEMs in.
The updated status table:
We removed ETMU07 from the suspension tower, after confirming that the balance was still good. Bob put it in the oven to bake over the weekend. The spring plungers and our spare magnets are all in there as well.
I tried to remove the grippers from ETMU05, and when I did, both side dumbbells came off of the optic. Unfortunately, I was working on getting channels into the DAQ, so I did not clean and reglue ETMU05 today. However Joe told me that we don't have any ETMY controls as yet, and we're not going to do Yarm locking (probably) in the next week or so, so this doesn't really set any schedules back.
The cleaning of ETMU05 will be tricky. Getting the residual glue off of the optic will be fine, but for the dumbbells, we'd like to clean the glue off of the end of the dumbbells using a lint free wipe soaked in acetone, but we don't want to get any acetone in the magnet-to-dumbbell joint, and we don't want to break the magnet-to-dumbbell joint. So we'll have to be very careful when doing this cleaning.
The Status Table:
I have made a little bit of progress on the PEM channels. I have begun writing up detailed instructions in the DAQ Wiki page on how to add a channel to the new DAQ system. I have followed those instructions thus far, and can see my channels in the .ini file (and in the daqconfig gui thing), but I don't have any channels in Dataviewer or DTT.
There are some tricky "gotchas" involved in creating new models and channels. Some examples include: No use of the characters "DUMMY" in any channel name. The makefile is specifically hardcoded to fail if that string of characters is used. Also, you must have at least 2 filter banks in every model. Why? No one knows. You just do. The model won't compile unless you have 2 or more filter banks.
My efforts today included ~3 reboots of the frame builder, and ~2 reboots of c1sus. When Kiwamu and I rebooted c1sus, we burt restored to some time in the last 24 hrs. Some of the SUS filters on some of the optics were not set correctly (things like the bounce roll filter), so we turned all of them on, and reset all of the input and output matricies to be the correct combination of +1 and -1's to make Pit, Pos and Yaw. The tuning seems to happen now-a-days in the gains for each DOF, and the gains were set correctly by the burt restore for every optic except PRM. We made some educated guesses for what the gains should be based on the other optics, and PRM is damping pretty well (these guesses included reducing the SIDE gain by ~10 from the BS SIDE value, since the analog gain of the PRM SIDE sensor is much higher than others). We'll have to fine tune these gains using some Yuta-developed method soon. Or find a burt snapshot that had some non-unity values in there.
We put ETMX back in its tower, and confirmed its balance. It might be pointing a teensy bit upward, but it is way less than the DC pointing offset we see when we put the OSEMs in the towers (since the PDs and LEDs have some magnetic bits to them).
Discussions are ongoing as to where the ETM should sit on its table, but we'll probably toss it into the chamber later this evening.
I took ETMY out of the magnet gluing fixture, and put it in a ring, in the foil house. It is ready to have the wire winched and get balanced at our convenience.
ETMU05 (ETMY) had its wire winched to the correct height, was balanced, and had the standoff glued. Since it's kind of like final exam week at Caltech, Suresh had his suspension exam today, and did most of this work himself, with me hanging around and watching.
As you can see in my almost entirely green table, all that is left to do with the whole suspensions project is bake the optic (hopefully Bob has time / space this week), and then stick it in the chamber! Hooray!!! (Can you tell I'm excited to not spend too much more time in the cleanroom?)
Kevin was working on characterizing all of our RF photodiodes for the upgrade, and he discovered that REFL11 didn't work, as described in elog 3890. Rana was working on fixing it, but then he went off to Japan.
I visually inspected the components inside the RF cage on the REFL 11 circuit board inside the PD. Most of them were okay, but the connection between L5 and C33 (the big tunable inductor and the next capacitor in the path) was totally flaky. the leg of the inductor had been soldered directly to the trace on the PCB, and the inductor was a little bit tipped over, and pulling the trace off the board. I wiggled it a little while trying to see what was going on, and the trace broke. Since there is nothing going on between L5 and C33, just the trace, I used a piece of resistor lead to attach the two. The connection now seems very robust. I'm a little worried about the connection between the inductor and the board on the other side, but I can't see it since it's under the inductor itself.
Also, the soldering of L4 (a standard surface mount component type body) to the board seemed totally shoddy. I was desoldering the first side, and the whole inductor popped off. It was clear that the inductor was making a physical connection to the board, but not a nice solid electrical connection. So I resoldered it on. (On Alberto's schematics, it is listed as a 633nH inductor. I can't find any of this value, so I just put the same one back on. The best I could do to confirm the component was still okay was measure its resistance, and compare that to a similar inductor of a similar value. It seemed okay.)
After that I powered up the PD, and took an electrical transfer function, just to have a look-see. It seems kind of okay, although the resonance seems to be closer to 13MHz than 11MHz.
Since we would like to remove the capacitor that is in parallel with the diode itself, which will then change all of the resonant conditions on other components, I didn't worry too much about the resonant peak for tonight. We're going to have to look in on this though.
Also, I'm leaving the optical check-out for Kevin, so he will let us know if I magically fixed the PD, or if it needs some more work.
Photos of the circuit board (mostly Alberto's mods) before and after I fitzed with it are on Picasa
More testing. Probably more fixing.
The nightly backup of the frames and the /cvs/cds directories is back up and running. We are free again to do crazy stuff at will, and it will all be saved for eternity.
I wish I could use a bigger font for this, but, the suspension work is totally done for the upgrade!!!
Now, nobody break any suspensions, or we're not going to be friends for a while.
Koji and I put ETMY back in its tower, and made sure that both scribe lines are at the correct height. We also confirmed that the balance is good (as Suresh mentioned in a previous elog, since we balanced using the AR surface, the HR surface is pointing downward a little bit, but it's well within the OSEMs ability to correct.
While we were in there, we also looked at Tip Tilt number 002. As mentioned in elog 3645, the pitch pointing was off by a little bit. Since the TTs don't have actuators, the pointing has to be pretty good. We tweaked the balancing, and now the reflected beam goes completely back into the laser aperture, so it's as balanced as it's going to get. This TT is now ready for installation onto the ITMY table as part of the SRC.
Kiwamu confirmed that he's going to install these optics tomorrow, since he's doing some other alignment work today.
Just for good measure, the Table:
The Seismometer channels are once more being recorded. Alastair brought Gur1 back from the ATF the other day, and today I put it in its place below MC2 (yeah, the numbers are backwards. But they always have been.)
I checked the matching between BNC inputs on the breakout box to the ADC channels as labeled in the SimuLink diagram. To do this I had all 32 channels activated, and I put a 1Hz, 1Vpp sine wave into various BNC inputs to see what channel they showed up as. At first things were a bit backwards (BNC channels 1-16 going to ADCs 16-31, and BNCs 17-32 going to ADCs 0-15), but then Joe quickly flipped the cables on the adapter board in the back and things are in the correct order now. Channel 1 on the BNC board corresponds to channel 0 on the ADC, etc.
I checked that jumping near each seismometer made the signals spike, which they did.
I then changed the channel names in the c1pem.mdl SimuLink diagram to match the old channel names for the Guralps and the accelerometers, and deleted all of the other channels that aren't being used. There's a table in the diagram to indicate what goes with what, as of today. If you do anything to the PEM diagram, please update the table so it's easy to look things up.
I recompiled the code, but have not yet restarted the frame builder since Zach and Kiwamu are working on some things in the chamber, and I don't want to be annoying (so the channels aren't actually being recorded quite yet).
Edit, 7:15pm: Just kidding. Something didn't work, and I have to track down what. I'm not getting any data yet.
- Do the following list for all of the testmass chambers.
- Start slow pumping
[Kiwamu, Jenne, Koji, Osamu]
We have mostly prepared the IFO for pump down.
After lunch [Steve, Bob, Koji, Kiwamu, Jenne, Joe, Joon Ho, Vladimir, Osamu] put the access connector back in place. Hooray! Steve still has to check the Jam Nuts before we pump down. Kiwamu checked the leveling of the IOO table, and fixed all of the weights to the table.
For all 4 test masses, bars (upside-down dog clamps) were placed to mark the alignment of 2 sides of the suspension tower. All test mass tables were re-leveled, and the weights fixed to the tables.
For ETMY, PRM, BS, SRM, we confirmed that the OSEMs were close to their half-range. ETMX was already fine. ITMY (the screens and the optics wiki are still old-convention, so this is listed as ITMX! No good!) OSEMs are pretty much fine, but ITMX desperately needs to be adjusted. Unfortunately, no one can find the standard screwdriver (looks like a minus), to adjust the ITM OSEMs. All the other towers had hex-key set screws, but the ITMs need a screwdriver. We will ask Bob to sonicate a screwdriver in the morning.
What was the point:
I twiddled with several different things this evening to increase the power into the Mode Cleaner. The goal was to have enough power to be able to see the arm cavity flashes on the CCD cameras, since it's going to be a total pain to lock the IFO if we can't see what the mode structure looks like.
Summed-up list of what I did:
* Found the MC nicely aligned. Did not ever adjust the MC suspensions.
* Optimized MC Refl DC, using the old "DMM hooked up to DC out" method.
* Removed the temporary BS1-1064-33-1025-45S that was in the MC refl path, and replaced it with the old BS1-1064-IF-2037-C-45S that used to be there. This undoes the temporary change from elog 3878. Note however, that Yuta's elog 3892 says that the original mirror was a 1%, not 10% as the sticker indicates. The temporary mirror was in place to get enough light to MC Refl while the laser power was low, but now we don't want to fry the PD.
* Noticed that the MCWFS path is totally wrong. Someone (Yuta?) wanted to use the MCWFS as a reference, but the steering mirror in front of WFS1 was switched out, and now no beam goes to WFS2 (it's blocked by part of the mount of the new mirror). I have not yet fixed this, since I wasn't using the WFS tonight, and had other things to get done. We will need to fix this.
* Realigned the MC Refl path to optimize MC Refl again, with the new mirror.
* Replaced the last steering mirror on the PSL table before the beam goes into the chamber from a BS1-1064-33-1025-45S to a Y1-45S. I would have liked a Y1-0deg mirror, since the angle is closer to 0 than 45, but I couldn't find one. According to Mott's elog 2392 the CVI Y1-45S is pretty much equally good all the way down to 0deg, so I went with it. This undoes the change of keeping the laser power in the chambers to a nice safe ~50mW max while we were at atmosphere.
* Put the HWP in front of the laser back to 267deg, from its temporary place of 240deg. The rotation was to keep the laser power down while we were at atmosphere. I put the HWP back to the place that Kevin had determined was best in his elog 3818.
* Tried to quickly align the Xarm by touching the BS, ITMX and ETMX. I might be seeing IR flashes (I blocked the green beam on the ETMX table so I wouldn't be confused. I unblocked it before finishing for the night) on the CCD for the Xarm, but that might also be wishful thinking. There's definitely something lighting up / flashing in the ~center of ETMX on the camera, but I can't decide if it's scatter off of a part of the suspension tower, or if it's really the resonance. Note to self: Rana reminds me that the ITM should be misaligned while using BS to get beam on ETM, and then using ETM to get beam on ITM. Only then should I have realigned the ITM. I had the ITM aligned (just left where it had been) the whole time, so I was making my life way harder than it should have been. I'll work on it again more today (Tuesday).
What happened in the end:
The MC Trans signal on the MC Lock screen went up by almost an order of magnitude (from ~3500 to ~32,000). When the count was near ~20,000 I could barely see the spot on a card, so I'm not worried about the QPD. I do wonder, however, if we are saturating the ADC. Suresh changed the transimpedance of the MC Trans QPD a while ago (Suresh's elog 3882), and maybe that was a bad idea?
Xarm not yet locked.
Can't really see flashes on the Test Mass cameras.
I undid Yuta's temporary setup, and put beam back on both WFS. Since Koji had just aligned the Mode Cleaner, I centered the beam on the WFS using the WFS QPD screen, while watching the WFS Head screen, to make sure that the beam was actually hitting the QPD, and not off in lala land.
- We must check the MCWFS path alignment and configuration.
We successfully aligned the X arm. No big deal. Nothing to write in giant colorful letters about. If we thought it was tricky, we'd be excited. But since we're rockstar grad students, we can do this anytime, with one hand behind our back.
Earlier this evening, Kiwamu put a PD at the dark port. After starting with the usual steering beams around and approximately centering them by finding the beam on the SUS tower, we saw that we could see the fringes on a 'scope hooked up to the dark port's new PD. We could make the dip in the scope trace go away by misaligning the ETM, so we were confident that it was due to some kind of resonance in the arm. We then fine-tuned our beam centering by moving the optics in either pitch or yaw until the fringe went away, wrote down the number, then moved the other direction until the fringe went away, and then put the optic back in the middle of those two numbers. We did the ETM first, then the ITM (because the beam on the PD is sensitive to the ITM pointing, so we didn't want to have to move the ITM very far). We saw that the cavity had a visibility of ~56% when we had finished with this method.
We then went to look for the flashes transmitted through the ETM. We were not able to see them on a card, but when we looked with an IR viewer at the back face of the ETM, we could see the flashes. We stole a spare CCD camera found on the PSL table, and the camera power supply from the RefCav Refl camera, and set up a CCD camera with telephoto lens on the ETMX Trans table, looking directly at the back of the ETM. We hooked the camera up to the regular ETMX camera cable, so we can see the flashes in the control room. You can see them here:
While the cavity was aligned, here were the slider positions: