Awaiting a more detailed aLog but posting now to keep the masses up-to-date, I recently learned that the ETMy TFs from last night appear to show that it is free and clear of mechanical issues. Doug and Jason are taking an IAS shot shortly. I'm hoping they'll get assistance with damping if they need it (I'm tied up in the staging building).
TMS crew went into BSC6 to look at the viewports. What was found was a significant misalignment in pitch, which is preventing the retro-reflection and HWS beams from making it through the table and out the viewport. The two viewports on the South door look so much better, after the recleaning! --- Pictures: First picture shows where the TMS beam is entering the vacuum system through the viewport. This beam is misaligned on the TMS table in pitch, and diagnosis of the cause is ongoing today, so realignment/fixes will take place tomorrow. Second picture shows a defect in the viewport, on the outside surface, that may be an issue for the Hartmann Sensor - will know more after TMS fixes. The third picture shows the TMS beam close up, going through the viewport, and shows that there are point features, but no scratches or defects where the beam is going through the viewport, today. The viewport looks good in this region, so I think it's unlikely that an issues will arise from alignment, which will move the beam on the viewport. Fourth picture shows a feature of the viewport that's near the edge. It might be helped with cleaning, but no threat to TMS/HWS beams, so not worth the risk to try to mitigate. Pictures 5 is of the other viewport (BSC6 South Door, East Viewport). There are a number of features that are visible, but already cleaned with freon, so likely in coating or a surface feature, and relatively small. Picture number 6 shows a close up of the TMS beam on the inside surface of the viewport. Point features are visible.
When we went to BSC6 to check the viewport for the ALS green beam, we've quickly found out that the beam was not hitting the EY, not even the primary.
The beam was at least 4mm too high on the secondary (picture will be posted by Cheryl). That's a huge number.
Since there's no lens/curved mirror between the ALS table and the secondary of the TMS telescope, and since the distance between the top periscope mirror of the ALS table and the secondary on the TMS telescope is something like 3.5m roughly, we're talking about 1mrad-ish number if it is something on the ALS table, and much much more if it is something on the TMS.
Vincent assured me that the ISI was good.
Hugh looked at the dial gauges of the HEPI and told me that the changes since May/07 are all 0.1mm or less. That's over 3 or 4mm distance. That's nothing compared to what we're seeing.
There was no change in the TMS bias voltages since we "finalized" the alignment a week ago, and though the OSEM values showed some drift it's about 1000 counts maximum, and that doesn't sound that big. Nobody worked on the ALS table since the last alignment. Picomotor driver cable was disconnected last time we finished working on that.
At this point, there are three potential cause of this:
1. Wedge of the viewport
BSC6 high quality viewport was removed from BSC6 for cleaning after our "final" TMS alignment, and then installed again.
Though this is "no-wedge" viewport, the spec (E1100267) says "up to 5 arc minutes", which is 1/12 degrees or 1.45 mrad. Assuming the refractive index of n=1.45 and using a small incident angle approximation, the angle deviation caused by this viewport is approximately up to
1.45 mrad * (n-1) = 0.65 mrad.
If the viewport was rotated 180 degrees after cleaning, that will cause up to 1.3 mrad difference.
Since the distance from the viewport to the secondary along the optical path is roughly 3m, 1.3 mrad roughly corresponds to 4mm shift.
2. Bias of the PZT mirror on the ALS table
We've found that one of the four inputs for the PZT mirrors is 14 Volt for whatever reason. I'm quite certain that the offset was there when we aligned the TMS. Indeed, when I disconnected the input cable from the PZT driver, the beam was totally misaligned and didn't even come out of the ALS table.
We still don't know why there's such a stupid offset, but anyway it's not impossible (though not very likely) that this offset drifted over time. The iris is much closer to the PZT mirrors than to the TMS secondary, so a tiny change in the PZT mirror angle could lead to a big position change on the secondary.
3. TMS mirrors
It's not impossible that the TMS mirrors got bumped. Again this is not very likely, because there are only two relevant mirrors that are easy to bump, and it's kind of difficult to bump them to cause problem mostly in pitch only.
Whatever the cause of this is, we'd like to fix this by:
If possible at all we'd like to do this the first thing in the morning.
Bubba says that it was put back in rotated by 180 deg. He's sending somebody to rotate it back.
Picture showing the secondary telescope mirror and the ALS beam. The beam position is significantly above the center of the mirror, about 4mm, as measured on 5/22, but was well centered when TMS alignment was completed. Picture by Alberto.
For the record--will report the current position of the HEPI relative to the position after we first installed the Actuators on May 3 & 4. Likewise this is after latest OK from Initial Alignment before the Actuator install. We see a tilt about the horizontal line running from SE to NW of less than 100urads & similar magnitude CW rotation about the vertical axis. The largest absolute motions are +0.1mm vertical on the SE corner and 0.2mm south motion on the SE corner. All other shifts are smaller and 3 of the 10 readings are zero.
Added an SSD drive to the tape backup machine, this has sped up the backup process by a factor of 4. Jonathan installed an evaluation one time password login machine called cdsssh onto the 10.20 network. The nat router is routing a non ssh port through to it for testing.
Attached are plots of dust counts > .5 microns.
Measurements began at 102 168 1447 (~ 17:23 PST)
The fourth dust barrier was repaired and installed between HAM4 and the new Mode Cleaner Tube. Start of work checks on compressors,hoses, etc were completed and brushing started in BSC2. Upper, collar and mid sections were all brushed today and only ONE (1!) drill was used.
The attached are diagonalization measurements run on H2 SUS ETMY M0 & R0 for Vertical and Yaw DoFs this afternoon. Every measurement indicates ideal isolation of at least 20dB on both DoFs for both top masses.
The attached are the latest TF measurements on H2 SUS ETMY M0 & R0 top masses. There may be indication of rubbing in the M0 Transverse DoF seen in the 0.6Hz to 2Hz band. All the other DoFs look fairly clean for all bands.
Summary of install of the new DAQ Test Stand (DTS X1) May 14th - 18thth Rolf, Dave, Richard, Jim. -------------------- We have installed the following X1 systems in the H2 EE building: Timing, including timing fanout and IRIG-B distribution. We are running the new Timing Master Fanout in the MSR with a GPS antenna connected directly to its F-type connector. DC power (12V) for the IRIG-B and timing fanout. Networking, including three switches: the general X1 network switch; the FE-DAQ network switch with 10GE link to data concentrator; the 10GE DAQ switch The x1boot machine, which is also the code build machine. RCG branch2.5 was installed and the x1ioppsl0 model was built. All file systems for user apps, rtscore, rebuild etc. were constructed. The NAT router connecting X1 with GC. We ran a GC line from the GC switch in the H2 racks. We installed a new Vyatta based NAT router, using the original GC address for the DTS (badger.ligo-wa.caltech.edu) We installed one IO Chassis with an AC PS, we booted one front end, the x1psl0 system. ------------------------ Next item is to get the DAQ fully operational.
Measurements on H2 SUS ETMY M0 & R0 began at 1021432185 (May 18 2012 20:09:30 PST). Estimated completion time is May 19 at ~04:00 PST.
Turbo pump was started yesterday at 16:22 local time, pressure this morning had reached 3.4x10^-03 torr, no update on current pressure since CC has not turned on yet, but pump continues to pump.
Started turbo at 16:25 local time, about 30 min. later I started the CC, we see a pressure of 1.30x10^-05 torr.
Attached are plots of dust counts > .5 microns. I have also included plots of the mode for the dust monitors at end Y to show when they were moved.
Dan tested beam diverter and everything worked including the motor and the two reed switches.
That's strange as one of the two reed switches was stuck before, but somehow it's unstuck. Anyway it's good.
I'm curious to get my hands on this Beam Diverter, after my experience with building five of them. For me, the Sensor Magnet's polarity seem to affect the functionality for the Reed Switches (Chirs Guido mentioned the position of this magnet was more the issue for him).
Dave restarted all the models of h2seib6. Gerardo moved dust monitor 2 in the end Y LVEA into the clean room over BSC 6. The IOP watchdogs for SUS BSC6 were tripped (in chamber work)
Today, we finished fixing the PUM (L2) LR magnet/flag. We then verified that the suspension was free of any mechanical rubbing (many head to toe inspections) and adjusted all OSEMs to nominal settings, accounting for buoyancy. So, we are ready for TFs on this guy.
