Restarted the DAQ to add h1pemmy model channels, and for suspension model changes. The h1broadcast0 computer was running slowly, with a heavy load average and memory swapping occurring constantly. Rebooted h1broadcast0. It currently has 12G of RAM, may need more.
The aLOG maintenance has been completed.
Changes:
Took VM snapshot, then installed all current updates available in WU on h0dust. Also installed the .NET 4.5.1 update and associated patches. Patch process took about an hour, two rounds of updates.
Work Permit 4509, update windows virtual machine for dust monitors
Throughout the day as well
LASER IS ON - Output Power = 28.3 W - Watchdog is active - System status is good PMC - Locked for 14 hours - Refl Power = 1.2 W, Trans Power = 10.1 W FSS - Ref Cav locked for 14 hours - Alignment looks slightly off but still resonant, PD threshold = .812 Volts ISS - 13.2% diffracted power - Saturated 14 hours ago.
As a reminder the aLOG is down for maintenance today starting at 12:15pm pacific. Please save your log entries as drafts or post them to the log book prior to this time, or they will be lost.
The maintenance is completed.
model restarts logged for Mon 17/Mar/2014
2014_03_17 23:20 h1fw1
unexpected restart of h1fw1, it has gone slightly unstable in the past week.
This is the only restart since last Thursday.
TMS Work (Corey, Jax, Keita, Margot)
Apollo roughly positioned the ISCT-EY Table (via floor markings).
Chamber Floor was first cleaned upon entry for work (did not do an exit floor wipe). Margot then entered the chamber to remove First Contact from inside surface of pair of TMS Viewports (then went out and removed First Contact off outer surfaces). She mentioned "finger prints" on the outside surface of one of the TMS viewports; Margot will document in the DCC.
By eye, we checked position of the table, we ended up pushing the table about 3" west. We then attached ducting between the chamber and the table. Then we went in to check our line of sight from the TMS Table to the Table Periscope. This required us to move the GREEN periscope an inch east, and also the top periscope mirror down 4-6". At this point the laser wasn't quite making it down the ductThis is about where we ended things last evening.
Dust Monitor Check Of Purge Air For BSC10 (Corey, John, Keita)
John whether there was dust coming from the purge air. So I, with handheld Dust Monitor in hand, crawled under the ACB, and took a few measurements from the Dust Monitor (which was running continuously). I took measurements at four spots above the input of the purge air. At the highest point, I had readings which would hover between 1500-2500 counts of 0.5um particles. At the lowest point (with sensor of Dust Monitor right at the input), the 0.5um counts could be kept at basically 0-counts (with flashes of a few hundred possibly. So, it would seem the purge air is relatively clean.
These 2 statements seem contradictory:
"At the highest point, I had readings which would hover between 1500-2500 counts of 0.5um particles. [At the lowest point ...] So, it would seem the purge air is relatively clean."
Maybe can John elaborate at where he thinks the high counts are "coming from" if not the purge? Is it just that the air is turbulent in chamber and stirring up the 1500-2500 counts already in the chamber?
Corey saw high background levels in the beam manifold but was able to drive the particle counts to zero by moving the detector close to the purge port at the floor of the beam manifold. I walked around the VEA sampling and found low levels throughout. Counts inside cleanrooms were close to or equal to zero except at the open BSC door. There was activity here as well as equipment staged. Corey was inside and Keita was outside at the BSC entrance. The overhead work platform reduces the effectiveness of the clean room in this location. Inside, the arm cavity baffle obstructs access to the beam manifold so any work in the beam manifold requires a person to laydown and slide under the baffle. This may very well abrade clothing. I recommend we establish a horzontal clean flow as we have while working in HAM chambers.
A reminder that the purge air can only provide 25--50 cfm of air flow into the chamber. In a 6 foot diameter tube (beam manifold) this translates to air velocities of only 0.6 to 1.2 feet per MINUTE. Think how far you walk in a minute.
My impression is we have a reservoir of particulate in the vacuum chamber from the series of operations which have taken place - for example there have been two cartridge installs and one removal. Also this cartridge is an early assembly - probably assembled prior to some of the "in process" cleaning steps we have adopted.
Yes, I should elaborate a little (was quickly entering alog during Morning Meeting). So we did measure counts while I was in BSC10. And seemed like we had steading counts in the several thousands [for 0.5um counts with continuous sampling]. When I took measurements along the Purge Air plume, I would get up to 2500 at the most at the top of the plume (6' high). As I went closer and closer down to the Purge air inlet, the counts started to drop. And it was zero right at the inlet.
So the picture looked as though we have a baseline of particles floating in the chamber. And in the turbulent air above the Purge Air inlet the counts waiver a bit, but counts decrease the closer you are to the inlet. So above the purge we have particles moving around more (vs further away from purge these particles are more "statically" floating...perhaps they are more on the floor when someone like me isn't shuffling them into the air).
Basically we have particles all over the surfaces in the chamber/tube. They may be gently floating around or resting on the floor. They get rustled around when we work in-chamber & also get blown around and away from the Purge Air inlet. We need to remove these particles...which I know is obvious and daunting.
We're going to coninue wiping these particles on the floor toward door, but not sure what that does. Hopefully, particles get attached to our wet wipes, but I wonder if particles just get pushed to the edge of the floor and then fall over the edge of the temporary floor and then rain down to the bottom of the chamber. Sad sad.
Are these raw or normalized counts?
J. Kissel, A. Staley The H1 HAM2 ISI consistently trips using the guardian on the GS13s, right as the X, Y, Z, RZ isolation filters begin to turn on, just after the RX and RY alignment biases are slewed. I had thought it might have been because I found the GS13s in high gain mode (why? because of a restart of the guardian process maybe?), but I switched them back to low gain mode (with dewhitening ON) and things still trip because we're trying to engage horizontal GS13s that that just been yanked around in tilt. I confess, we *didn't* reset the CPS offsets and store them in the target before getting started and I don't know the difference between the equilibrium state and the current target, nor do I know the last time they were reset and stored, so it might be fine if I just do that. I'm surprised to see the RX and RY alignment biases being ramped in between turning on each of the isolation filters already. We have certainly discussed doing this, but I would have expected more testing to iron out these bugs. Jamie's update aLOG doesn't mention anything about it, other than nodes have been restarted with some minor bug fixes. For the evening, I left the requested state in damping, and brought up the isolation loops using the commands script. That works because it doesn't play with the biases until the isolation filters are completely engaged. Also note, that if you manual put the ISI into the HIGH ISOLATED state, and then switch the request to such, it turns the isolation loops off and starts from scratch. Not desirable, but may be tough to code up / or insure that you're actually in high-isolated. I post to examples of the GS13 trip, but it's clear what's happening, as I describe above.
(Alexa, Jax)
The PZTs on ISCTEY are now working. We had found that the AA chassis hooked up to the DAC channels was turned off. The PZTs move as expected. When we run the servo we might want to be aware of the sign convention (it seems to obey positive counts in pitch moves the beam down).
NOTE: Anti-Aliasing chassis in slot 9 of rack ISC-C1 has no power cable. Filiberto help!
After Travis had notified me of a problem on ETMy where the copper clamps on the ring heater were touching when it was moved into final position I went in chamber and made some adjustments to keep the upper and lower clamps separated. Decided to check if the same problem existed on ITMx and ITMy. Unfortunately, ITMy had part of its macor break while I was adjusting the copper clamps. ITMx had the glass former break sometime after it's installation onto the lower quad. Both lower ring heaters have been removed.
[ FYI ... There is a specially designed Ring Heater Segment Replacement Fixture (D1101253), which is to be used ANY time a segment needs to be removed from a QUAD, if a dummy mass or a TM is also on the QUAD ]
Note, the ITMx unit has already been stripped of it's lowest dummy mass in prep to load the new glass mass later this week. So, the ITMx unit had extremely easy access for this RH work and no fixturing was required.
It's worse than I originally thought. The glass former broke along with the macor on the ITMy lower ring heater.
Apparently, damage was done (also) to the very tip-end of the glass former when the adjustment was made (14-March) to the copper clamp plates of the lower RH segment (assembly D1001895-v8 SN-210) on the ITM-Y quad. This damage was not revealed until the lower segment was dis-assembled. Photos are attached.
Regarding the lower ITM-Y assembly issues, see the attached (PDF) package of images.
The following feedback (attached) has been received, as guidance, from SYS
Dave O and Stefan B We measured the round trip gouy phase of the PRC using the same phase-locked sub-carrier that we used to measure the PRC length. We scanned the sub-carrier offset frequency over a full spectral range of the PRC (2.6 MHz) from 68.4 MHz - 72.4 MHz. We then monitored the amplitude and phase of the beat- note as measured by Refl-Air-B diode. Two plots are shown. The first shows the full sweep. Three tracs are shown. The blue trace is the transfer function for the full beat-note signal scanned over a full PRC FSR. The other two show the traces, when half the photo-diode is blocked and the sub-carrier is locked on either side of the main carrier. Unfortunately the interferometer lost lock half-way through both of these scans. The broader bumps show the resonance of the TEM01 modes. The second plot is the same trace zoomed in around this area. From this plot we can determnine that TEM01 modes resonate at 375kHz +/- 10 kHz off the main resonance and hence the round trip guoy phase for the PRC is 52 +/- 3 degrees.
I did some comparison of these results with some predictions from a Finesse model of the PRMI, and also compared with the results of the beam size measurements reported here
I attach plots with the predicted PRX Gouy phases over ITMX substrate lens power and PR2-PR3 distance offset.
The left-most solid diagonal line is the line that comes from the beam size measurements, and the right-most solid diagonal line is the one coming from the Gouy phase measurements (with two dashed lines representing the error bars there). The blue line is the expected ITMX substrate lens power (f=230km, 1/f~4.35uD).
It would help to know if the PD was covered left-right or top-bottom to know if you measured Gouy phase in x or y direction, but for now I just considered both possibilities.
One possible explanation for the larger measured Gouy phase than expected from the beam size measurements is if PRX and PRY were not ideally matched when the measurement was made. If ITMY was not heated enough to match ITMX, the PRC has a kind of "average" Gouy phase that is larger than the PRX Gouy phase on its own.
The contours of equal Gouy phase over the two varied parameters is the same as the contours of equal beam size, so there is still no chance to distinguish between ITMX substrate lens and PR2-PR3 offset (or PR3 Rc).
