Posted are the 30 day particle count trends for the LVEA. Mostly all good. The normal pattern of a few sharp spikes that clear quickly in random cleanrooms is repeated in these trends. The cleaning crew (Christina, Karen, and Vanessa) continue to do a fantastic job of keeping the LVEA clean and the cleanrooms are working well at cleaning up the air inside the cleanroom.
    

Betsy, Keita, Kissel, Cheryl

We spent all morning aligning the PSL beam from the IMs through the MC bypass, PR3, PR2, PRM, BS, ITMs, and back reflections from the ITMs reverse to PRM.  We broke for a late lunch only to come back and find things misaligned again for unknown reasons.  We spent a few more afternoon hours on this but will have to restart again tomorrow, since it seems we need to align the entire chain of 12+ suspensions in one foul swoop and we ran out of steam today.

Also to note, PR3 was fussy to use today - we couldn't get it to damp in all 6 DOFs and think we tracked it down to strange BIO settings which may or may not be stuck.  Didn't have time to diagnose...

During the installation of the OFI table into the cage some time ago, the table slid and came to rest against one of the corners of the cage cracking the beam dump, today I replaced the broken input baffle beam dump D1001920-v4 SN001, with SN003.

Since the reflection of IR beam on septum window AR is so small, we shot a red laser pointer beam from HAM5 through septum so the beam clears the HAM6 iris closer to HAM5, and falls on the second iris closer to VOPO within a mm from the center. Sheila calculated the deflection difference between IR and red, and it's so small it doesn't make much difference over the lever arm (a meter or two) in this case.

There were two beams coming through the septum, we took the first one (brighter, and towards +X) as the main beam.

There were three beams reflected off of the septum into HAM5. We took the first two towards +X as the main beams to dump.

We also confirmed that the scribe mark showing the thickest side of the septum is -X for the ZM path and +X for the OMC path.

Pictures will be added later.

F. Clara, R. McCarthy, T. Shaffer

Work corresponding to FRS4559.

Summary: While we did manage to isolate the cameras from their base, the grounding problem still exists.

DetChar noticed a noisy source that turned out to be a grounding issue with the HWS cameras. The above FRS was filed and then T1600449 was created as a solution that LLO had found to isolate the camera. Just as T1600449 outlines, the camera base position was marked with some spare clamps, I then disconnected and removed the camera from the base, and then I laid the Kapton on the base. Reassembling this assembly required the use of a nylon 1/4"x20 0.5" screw to hold it from the bottom, and a removal of all other metal hardware. While I worked on this, Fil connected the shield to the Hirose connector. Once we were done, we plugged everything back in and tested it. No good. We double checked our work and couldn't find a source that might cause the grounding, so we unplugged the camera and made sure that it was actually isolated. It was. The LLO alog30372 said that they only checked it was isolated while it was unplugged. So we went hunting.

Fil poked around some more and then called in some backup from Richard. The three of us taped up the bottom of the power supplies where they contact the metal bars that hold them up inside the table enclosure (see attachments). This also did not work. Some more hunting from Richard found that the photo detectors were also grounding to the table, and possibly other sources. We could choose to find all of these sources and find a way to isolate them all, but for today this was where we ended. Tomorrow we will head to the ends to continue T1600449.

Attachments are: HWSY shown with position clamped and Kapton on, a taped base, and HWSX final.

WP 7222
FRS 4559

Modified HWS camera mounts to isolate grounding per T1600449 and D1200566.

1. HWS camera positions were marked before disconnecting
2. Kapton tape was used between camera and base
3. A nylon screw was used to hold both together
4. Camera was tested for isolation to table without any cables connected. Power cable was modified per D1200566.
5. HWS breakout chassis and Polarization PD whitening chassis were isolated from table with kapton tape

Camera tested good (isolated ) with no cables connected.

F. Clara, T. Shaffer

WP 7231

LED chamber illuminator was replaced with new modular LED light. End stations will be replaced later this week.

I've been measuring this, at least once per week, but haven't always made a log entry.  

Laser Status:
SysStat is good
Front End Power is 35.76W (should be around 30 W)
HPO Output Power is 153.0W
Front End Watch is GREEN
HPO Watch is GREEN

PMC:
It has been locked 9 days, 8 hr 47 minutes (should be days/weeks)
Reflected power = 23.77Watts
Transmitted power = 48.68Watts
PowerSum = 72.44Watts.

FSS:
It has been locked for 2 days 3 hr and 28 min (should be days/weeks)
TPD[V] = 2.294V (min 0.9V)

ISS:
The diffracted power is around 2.3% (should be 3-5%)
Last saturation event was 6 days 6 hours and 12 minutes ago (should be days/weeks)

Possible Issues:
PMC reflected power is high

FRS9496

Jeff K, Richard, Dave:

At 07:30 PST Thursday 23rd November (Thanksgiving Day) PR3 rang up over two minutes. The T3 top OSEM shadow sensor RMS exceeded the 110mV threshold for 20 minutes continually, which caused the IOP Software Watchdog (SWWD) to DACKILL the h1sush2a DACs, at which time the oscillation stopped. The h1sush2a system remained in this state for the rest of the holiday weekend until the SWWD was reset this morning. Within an hour the ring-up occurred again. This cycle has repeated itself several times today. Investigation is continuing and an FRS has been opened.

Attached plot shows a 30 minute second trend plot of the Thursday morning event. Data shown is:  T3's shadow sensor ADC channel (Ch 3), the h1suspr3 T3 DAC drive (Ch 9) and the h1susauxh2 M1 T3 Voltmon. As can be seen, the OSEM shadow sensor and the model drive ring up in Unisom, driving the coil driver. After the SWWD trips the DACs at the 20 minute mark, the coil driver is quickly zeroed, which causes a bumpy ring-down of the shadow sensor (which the model's output mimics).

Title pretty much sums it up.  Photos attached for your viewing pleasure.

Two DAQ issues happened over the past 24 hours:

At 10:31 Sunday 26 Nov PST, the new E18 RAID on h1ldasgw0 became full. I thought I had more time to start the wiper code and was refactoring it. I manually cleared some space and will run the old wiper for now.

At 05:20 the DAQ data concentrator (h1dc0) crashed. It had been running for 208 days 18 hours, and crashed because of the 208.5 days issue the old 2.6.35 kernels have. We plan on upgrading to a modern kernel before the next 208.5 days expire. The DAQ acquired no data between 05:20 and 10:11 because of this issue.

Following on from Keita's alog from yesterday, we spent all day attempting to convince ourselves that the SR chain of optics are hanging symmetrically within their structures, using little to no tooling.  Holding rulers up to various optics and structures, and painstakingly logging measurements, I could not find any reason to believe that the beam centering we've done between the center of SR2 and SRM is out by more than ~2mm.  The PSL beam line that we have set between the center of SR2 and SRM looks good to carry on.  Indeed, this may mean that the baffles do not look symmetric on the structures, but at least the beam path appears correct.  We'll revisit baffle positions an drawings tomorrow.

Meanwhile, since I was wandering the tube between HAM4 and HAM5, I took a look at the beam centering going through the newly built SR2 scraper baffle D1003300.  At first I was thrown off by the fact that the beam seemed to go through the baffle off center even though the baffle was installed using a template which I would have thought set it pretty close (within mm's).  A lunch break consult with Keita and Calum pointed out that the beam I was looking at was only the SR3-to-SR2 beam which straddles the centerline of the baffle ellipse hole with the SR2-to-SRM beam which is hard to spot when viewing the SR3-to-SR2 beam with an IR card.  A quick calculation, and a SW confirmation told us the 2 beams should be separated by 20mm and should straddle the centerline.   Now how to find the center of the hole while standing in the dark with a viewer card and not occulting the beam with your body...  I gave up trying to measure in-situ and instead opted for some pictures to scale.

Attached is the PDF scaled pic I used - I'm not spending any more time screwing around with the oddities of why the font is miniscule - what I did was:

- Scale the aperture in the picture to the 161mm dimension I read off the drawing D1003301 (for what ever reason Adobe makes starts the scale at a huge setting like some 40 inches or so)

- Using the new scaler, measure to the beam center shown in the picture

- 161mm /2 = 80.5mm is where the center of the aperture should be, so the beam center should be left of that by 10mm (half of the 20mm), 90mm.

- The beam is at 87.4mm.  Of course it's hard to estimate the beam center since the beam is ~20-30mm in diameter, fuzzy, and moves a bit.  I'd estimate the error of my ability to measure this centering to better than 5mm...  Feel free to redo.

Seriously, please let that be close enough.

I did however, take a picture of what can be seen from the plane of the MCTube Eyeball baffle closest to HAM4 on the beam path (see below).  Not sure I was able to place the camera on the beam line very well...  I can confirm that everything shown in the left lobe cutout of the baffle is in dead all HWS silver mirror reflections (and no metal from mounts).  It's hard to tell if there is a sliver of the right side of the SR2 optic still in the right portion of the right aperture lobe.  Maybe it's the angle of my camera view.  Dunno.