Attached are plots of dust counts > .5 microns.

Keita, JohnM, DanH

We did some work on the ETMY transmon suspension: clamping cables on the back face, and installing (but not tightening) the cross-braces on the front and back.  Pictures attached.

Before and after the clamps were applied we noted the values for the OSEMs.  Things changed after the clamping, but not too badly; JohnM has the numbers if you're curious.

One of the electropolished nuts for the cross-braces was malformed in a strange way, so the back brace is currently held up by seven bolts instead of eight.

We noticed there were assemblies of what looked like BOSEM magnets on the suspension's first stage...perhaps for eddy dampers that haven't been installed?

We also wanted to assemble some mirror mounts, but we could not find the finely-threaded adjustment screws.

First layer of exterior drywall has been put up on the acoustic enclosure. Insulation has been brought inside the LVEA (wrapped for the moment) for inside the walls.

X1 QUAD 03 BUILD 03

Attached are plots of the X1 QUAD 03 BUILD 03 M0 & R0 TF measurements from last night along with measurements from 01/06/2012. For the M0 mass, there is virtually no change in the resonances from the two measurements, which is expected.  The R0 chain, however, is the chain where the cabling attaches between stages.  On R0, all DoFs except Pitch appear to have not been affected by the cable lacing.  The R0 Pitch plot (pg 5) indicates the second major pitch mode has stiffened quite a bit since the 01/06/12 measurement.  The DC Pitch also decreased slightly for this measurement. Cabling between the stages may be the cause of the extra Pitch stiffening on R0, so a reassessment of the R0 cabling could prove useful.

Small weld repair performed on new vacuum bake oven (VBO-D) to repair leak stemming from manufacturing defect in external stitch welds. Cleanliness was maintained including a foiled welding helmet to protect the inside of the oven from contamination and the inside of Slim's head from government mind control rays.

Work done by Slim, MarkD and KyleR.

X1 QUAD 03 BUILD 03

The first set of matlab TFs for M0 & R0 masses on the latest QUAD build (QUAD 3 BUILD 3) with full cable lacing to the lower stages.  The M0 measurement agrees very well with the model for all DoFs, with the Pitch DC adjustment a little lower than the model (as expected from every previous measurement).  For the R0 measurement, the L and T second modes are slightly lower in frequency from the model and with the same lowered Pitch DC level discrepancy, although it is a bit more than the M0 difference.  Comparisons with previous measurements to follow.

X1 SUS QUAD 03 BUILD 03

Attached are the Diagonalization test results from yesterday on the X1 QUAD 03 BUILD 3. The build now has the full lacing of cabling down to the lower stages on the R0 chain.  Diagonalization tests were run for the M0 and R0 masses to assess Vertical and Yaw DoF isolation from non-contributing OSEMs.  Results indicate a slight coupling of the M0 F1 OSEM to Yaw about ~10dB isolation. Ideally, at least ~15dB is desired with isolation of at least ~20dB preferred.  All other DoFs for both chains are well-isolated from the non-contributing OSEMs.

M0 Vertical Diagonalization - at least ~31dB isolation from F1, F2, F3, SD
M0 Yaw Diagonalization - about ~10dB isolation from F1 but at least ~30dB isolation from SD, LF, RT

R0 Vertical Diagonalization - at least ~28dB from F1,F2,F3,SD
R0 Yaw Diagonalization - ~22dB from F1 and at least ~34dB from LF,RT,SD

We performed some tests with the Vibration absorbers of stage 1 with different Vitton pads (identical contact surface and different thicknesses). Measurements done without the vibration absorbers lids.

Parameters Surface: 0.25"x0.25"

Thickness:

- 0.0625"

- 0.125"

- 0.25"

Results:

- Reduction by a factor of 6 of the 217 Hz resonance on X, Y, RX, RY using pads with a thickness of 0.125".

2 measurements (2012 01 06 no vibration absorber - 2012 01 11 6 vibration absorbers)

https://svn.ligo.caltech.edu/svn/seismic/BSC-ISI/H2/ITMY/Data/Figures/Transfer_Functions/Comparisons/

LHO_ISI_BSC8_Comparison_TF_C2C_ST1_ACT_H_to_ST1_L4C_H_20120106_vs_20120111.fig

LHO_ISI_BSC8_Comparison_TF_C2C_ST1_ACT_V_to_ST1_L4C_V_20120106_vs_20120111.fig

- With the thickest pads (0.25") the vibration absorber are less effective

- With the thinnest pads (0.0625"), performances are similar (slightly better)

Next step:

- Tests with the lids on

(Corey, Jim, Vincent)

Yesterday (1/24) afternoon, Jim and I went in and swapped Stage1 Viton Shims (these are located under weights) mounted on the Access Walls of Stage1.  We removed 1/16" shims & inserted 1/4" shims.  Vincent will then make measurements on the system to gauge their performance.  (note:  before the 1/16" shims, 1/8" shims were looked at).

Attached are plots of dust counts > .5 microns.

I attached an isokinetic probe to the dust monitor at location 1 in the LVEA and turned it back on. It is sitting near the floor in the area by BSC3.

I replaced the fuse in the breakout box for dust monitor 7 in the LVEA (near the previous location of the H2 electronics racks). It had turned off at what looks like around January 22, 2012 12:00 UTC (from a plot of H0:PEM-LVEA_DST7_MODE).

I turned off the dust monitor at location 1 in the LVEA, which had previously been sampling the enclosure around ISCT4, as it was sitting on the floor without an isokinetic probe attached. It has probably been running without one since ISCT4 was removed. I would not use its data since then.

Attached are plots of dust counts > .5 microns.

Keita, MikeL, JohnM, DanH

We un-installed the OMC and associated cabling, QPDs, and optics from HAM6 this afternoon.  The OMC SUS is currently clamped down and double-wrapped in aluminium foil and AmeriStat on the top level of a rolling cart next to HAM6.  The SUS frame is dog-clamped to a cleaned optics bench on the cart.  We'll crane the whole thing over to its temporary home inside the ISCT4 meat locker soon.

From the top of the HAM6 ISI, the optics, tip-tilts, balance masses, hardware and cables were removed and were wrapped in aluminum and double-bagged in ameristat.  We put everything in five plastic containers next to the ALS table (in the mini optics lab) in the LVEA.  There are many hockey puck weights on the floor next to HAM6.

The components removed from HAM6 and stored in the containers are:

Black glass beam dumps:

3 double-glass V-shaped dumps
2 single-glass dumps
2 L-shaped dumps
1 flat dump (from overhanging the edge of the table)
some small black glass pieces

Tip-tilts:  TT0, TT1, TT2, optics removed.

Optics:

3 mirrors (from tip-tilts, individually bagged and labeled)
3 hi-reflectors: part numbers IP122-32, 33, and 37
1 CVI BS1-45P
1 CV1 mirror
1 CVI mirror-type-thing, with wedge, and with a chip on the side
1 CVI lens, PLCX-50.8-250.5C 

Optic Mounts:

5 2" DLC mirror mounts, one with a bad pitch adjustment (bagged individually, labeled as such)
2 2" lens mounts (one was used for a hi-reflector)

Dog clamps & clamps for mirror mounts

1/4-20s, separated by Ag-plated, SS, and vented SS

OMC QPD1 & 2, with cables, and cable connector bracket

PeterK and RickS

Today we used the Agilent RF analyzer to investigate the FSS OLTF.  We tried to make this measurement from outside the LAE, but found that the necessary cables (In1, In2, Test2 in) were not run from the TTFSS to the field box.
We found that the common gain (and likely FAST gain) sliders were not able to take advantage of the full range of the AD602 variable gain stages.  The conversion from slider units (0 to 1) to gain (-6 to 24 dB) is 0.031 slider units per dB with 0.5 slider units corresponding to 10 dB.  It seems that the channel is set up to give +,- 500 mV range and the AD602 needs +,- 625 mV to give the full -10 to 30 dB range.

We adjusted the half wave plate for the RefCav path to 190 on the dial to give more power such that we could achieve the desired UGF (to take advantage of the phase bubble) of about 450 kHz where we have about 52 deg. of phase margin (see attached plot, not that the UGF is at -10 dB on this plot).  The Common/FAST gains are 0.969/0.930.

After adjusting the gains, the Lock Acquisitions counter is at 277 when we left the LAE.

Summary: Photos show arm cavity baffle installation and the view of the baffle from the ITM and ETM. Part of a reflective bellows can be seen from the test mass through the H1 hole. I include a photo of the interior baffle surface that could be used as a dust witness plate near the test mass. Particle counts measured during installation did not exceed 100/ft^3 (>=0.5um).

Installation photos:

Figure 1 is an annotated selection of installation photos that Lisa A. took.

Glint search:

Figures 2 and 3 show photos taken to look for potential retro-reflections  - in particular, to find surfaces that reflect light scattered from the beam spot on one of the test masses back to the beam spot. This retro-reflection, and reflection to the beam spot on the opposite test mass, are thought to be the dominant paths for scattered light noise. For the side of the baffle viewed by the ETM beam spot, Figure 2, the camera and flash were set up in the beam path many meters from the baffle. The brightest retro-reflections from within the clear aperture were from the diodes and their mounting screws and from the edges of the bends in the baffle.

For the ITM side of the baffle (wide-angle scattering side), Figure 3, I placed the camera at the location of the beam spot on the test mass, except that I had to use the side that didn’t have an optic. The baffle is close to symmetrical so I believe that the actual beam spot would have a similar view of retro-reflections from the inside of the baffle. The brightest retro-reflectors (at least at visible wavelengths) are the backs of the photodiodes, screw heads, and the bellows on the spool between the manifold and BSC8, which can be seen through the hole on the opposite side of the baffle. The outside of this bellows would be a good place to mount a shaker to test for scattering problems. It would be possible to block the view of this bellows with a divider between the two sides of the baffle.

Contamination control:

The large equipment was first staged in the Y-manifold while the dam was located in the spool piece, separating cleaned BSC8 from the un-cleaned manifold. I had recently found that particle levels were ten times higher in the manifold than in BSC8 for similar activity levels, here, and wanted to use the dam to keep manifold activities from contaminating BSC8 and the ITM. Immediately after transport, I measured particle levels in the manifold next to the dam to be about 1000/ft^3 (0.5 um or larger). After the particle level reached about 150/ft^3 (~20 minutes of sitting), I removed the dam and left carefully. As I was leaving, I measured the particle level at about 200/ft^3.  

For our work in BSC8, we had to walk a short distance into the manifold to retrieve the staged equipment, so I wanted to have clean air flowing out of  BSC8 into the manifold (clean to dirty) rather than the other way around. I made sure that the clean room at BSC8 would overpower the clean room at the spool piece, where the Y manifold was open, driving air into BSC8 from its clean room and down the manifold to the opening at the spool. To do this, I turned off the purge air, had the C3 removed from over the BSC8 ISI, removed the C3 from the manifold opening and pulled aside some of the clean room curtains there to reduce pressure in the clean room at the spool. Previous experiments had shown that this produced a good air flow from BSC8 into the manifold and out at the spool.  Most of the air was coming in through the BSC8 dome opening so I checked the particulate level, finding under 50/ft^3 inside BSC8, even when a person was on the upper level working on the ISI.

Immediately after installation we carried the railing down the manifold, and I measured particle levels of about 50/ft^3 in BSC8 as Art walked down the manifold.

Figure 4 is a photo of the inside bottom surface of the baffle, showing a few dust particles. This surface is quite close to the test mass and may be a good witness plate to monitor accumulation of dust. I think we should photograph it again when we button up.

Robert S., Lisa A., Scott S., Art R., Manuel R., Thomas V., Jodi F., Chris K.

(Doug, Travis, Hugh, Annamaria, Jason)

The final pointing is PITCH ~ 9uradians to the required beam line
                      Yaw ~ 10 uradians to the required beam line

Having the Cartridge alignments and the GAP/parallel alignments accuracies close was very useful as the laser collimator return reflection was swinging through when the optic was released from the EQ stops.

Tightening the setscrews on the pitch adjuster screws influenced the pitch pointing by ~ 150 uradians.

Care must be taken to determine the HR reflection from the AR reflection.

One full turn of the sus pitch adjuster = about 400urads of pitch change.

1/4 turn of the static ISI adjusters = about 240 urads. This was done by tightening one sid and loosening the opposite and working through the 8 adjusters.

The arm cavity baffle alignment visually as seen through the theodolite is well centered. The baffle apurature is not perfectly round and so I averaged the gap about the ITMy. Previous measurements from the corner cube gave us a quantitative number for its location. The pusher assembly needs to be removed yet.

In the end all went well, but patience is needed and damping ring down takes 15 minutes or so to see the readout.

After the ACB crew had finished their work in BSC8, I entered the chamber to unlock FMy.  So, until further update, the status of the suspensions is: ITMy is LOCKED, FMy is UNLOCKED.  I'll leave it to the ACB and SEI crews to independently report their status.