This afternoon the TMS upper suspension was transported to the Y End Station. It has been mated to the Bosch tubing test stand for final assembly and alignment. 

Today, we suspended the ITMy glass PUM from it's loop - the pitch error was better than the metal hang (!) at ~400 uRad (note, better than ~1 mRad is the spec).  Prior to the pitch look, we spent a fair amount of time setting roll correctly.  The tolerance for getting the clocking of the mass correct is ~0.25mm which proved a bit difficult to set manually with the mass sitting on TFE caps.  We overshot a few times before settling in at having the prism-to-prism height diff off by 0.2mm.  We determined that the ergo arm would not have helped us since we had to push the TFE lower stops up for a little loop slack, roll the mass a fraction of a mm, and then release it to hanging for a reading of the pitch with the theodolite, a very iterative process.  This would have taken hours with multiple pump-downs of the ergo arm, likely not yielding better results than us doing it "by hand".

Since the loop looked good, we proceeded with installing the ITMy test mass into the sus structure.  We stole the base from the split rotation tooling and mounted the ITMy LS/LSAT/Weld Trolley on top of it such that the ergo arm legs would fit underneath while installing the optic.  The install went well, right through the open ring heater from the back of the LS structure - the ears only have a few mm of clearance with the structure, but it went well with 3 spotters.

Pictures to be posted on ReSource Space shortly.

Cyrus working on paging system
Filiberto extended the dust monitor power and RS485 lines near the new H2 PSL enclosure.
Fire department well testing
Electrical inspector on site
Ski working on air handler system

Activities listed on the white board:
LVEA:
PSL diode / chiller room
SUS / SEI test
squeezer / H1 restore
triage clean storage
welding setup
ICC @ HAM 7,8
HEPI Welding HAM 9

EX:
BSC 5 set, pier set

MY:
oplev test

EY:
ICC @ BSC 6
RGA @ BSC 10
Transmon assy
HEPI Station Run

Plots of > .5 micron dust counts attached. Note relatively high levels at location 7 (near previous location of H2 electronic racks). The dust monitor at location 1 in the LVEA (ISCT 4) has dropped out. There are also some drop outs in the data for the counts in the LVEA from when Filiberto was working on the system. 

Summary: we are close to reaching our goal of at least a factor of 10 attenuation down to 10 Hz. Further improvements could be made with acoustic damping tuned to the room modes, a new acoustic door, and reduction in make-up air flow. 


I studied the acoustic isolation of the H2 PSL enclosure even though it is not quite complete because it will become more difficult when the laser arrives and it becomes a clean room. In addition to its current performance, I also studied what might improve the isolation should we be limited by acoustic coupling at the PSL in aLIGO. 

Low frequency attenuation is about 20dB

I injected 5 Hz combs using a large speaker at distant locations in the LVEA and compared the signal on a microphone inside the enclosure to the signals from a microphone at 5 locations around and above the enclosure. The microphones were calibrated in situ and huddle tested.  Figure 1 shows the resulting amplitude attenuation plot. Currently, sound pressure levels are attenuated by a factor of about 10 at 100 Hz, nearly as good as the smaller (and thus more rigid) acoustic enclosures for iLIGO that had a factor of  about 20 attenuation. Although low frequency attenuation is difficult, we hoped to have a factor of 10 down to 10 Hz for aLIGO. Figure 1 shows that we mostly reached this, though there are a few high points that are likely associated with chamber modes and scatter associated with the difficulty of generating high signal to noise around 5-30 Hz. 

Damping would improve low frequency performance

Figure 2 shows that I got a slight reduction in amplitude at low frequencies when a single tuned damper and two bales of fiberglass were in the room (I moved them in, blue, and out, red, several times). If we placed tuned corner dampers (as in the iLIGO acoustic enclosures) to fill all vertical corners we would have about 5 times as much damping material as in this test.

A better door should improve high frequency performance

The acoustic door was of inferior quality and will be replaced. Figure 3 shows that I reduced high frequency noise by stuffing the poorly sealed edges of the door with foam. 

Make-up air at 100% flow increases sound by at least 1.5 at low and high frequencies

Figure 4 shows that the make-up air increases the sound level by 1.5 at high frequencies, and also down at the putative room resonances below 100 Hz. The increase over background (no make-up air) is expected to be even larger when the LVEA does not have a lot of noisy clean rooms running. Running at a lower speed may help. 

Room modes 

Figure 4 also shows room resonances at about 11, 14, 22, 41 and 64 Hz. The 3 highest of these are consistent with the calculated lowest room modes:  axial – 23 Hz, tangential – 42 Hz, oblique – 63 Hz. The microphone was hung above the table for Figure 4. When the mic was hung near the wall,  there was also a strong 31 Hz peak, possibly the second lowest axial mode calculated at 35 Hz. The 11 and 14 Hz peaks may be due to structural resonances of the enclosure or the clean room structure within.

Penetrations 

I tested the stuffing of the penetrations by adding additional stuffing. Extra stuffing didn’t help on the feed-throughs without cables, but did on those with cables. It takes careful packing around the cables to maximize performance.

I corked the output duct and saw no reduction in sound, suggesting that our acoustic labyrinth is working well.

Robert, Rick

I have been looking for environmental coupling to the aLIGO electronics located by the SUS and SEI test stands in the Y arm of the LVEA. To test for vibrational coupling, I used speakers and shakers (photograph below shows accelerometer and shaker on one of the cabinets). I shook each rack using a 5 Hz ramped sawtooth, and looked for evidence of the 5 Hz comb in many of the working channels by looking for coherence between the channel and the accelerometer channel. Even though I shook the racks with more than 100 times the amplitude of the ambient background at most frequencies (see plot) I found no evidence of coupling - good job CDS.

B. Bland (and G. Moreno, T. Sadecki)

On Friday, the first piece of glass was installed into a suspension at LHO.  The ITMy Penultimate Mass (PUM) was loaded into its QUAD lower structure in the LVEA fiber welding cleanroom.  We utilized the ergo arm, and the Genie lift, as we encountered some leg interference between the ergo arm and the weld trolley which holds the lower suspension structure.  We will look into a different weld trolley base mount to alleviate this interference for the future installs.  Pictures of the maneuver are on ReSource Space (note the software uploads the library backwards, so start clicking pictures at the end for appropriate install sequence):

https://ligoimages.mit.edu/?c=736

Collection entitled "LHO ITMy Glass PUM Install" if the link above doesn't work.

After we do a test hang of this mass with it's new wire loop, we anticipate loading the ITMy Test Mass this week in preparation for fiber welding later in the week.

These clean rooms were not in use so I shut them down to prevent interference with interferometer locking.

Yesterday we mounted and routed the various cables from the QPDs and picomotors on the H2 ETMY Transmon ISC breadboard.

Using ISC breadboard layout D1101585 for the picomotor locations and D1000238 for the actual picomotor cable assembly, the connectors are conected as follow:

J1 (25-pin connector) = mounted in the connector bracket in the lowest location on the ETM side of the breadboard ( photo of the bracket)

J2 (4-pin mighty mouse connector) = M3 (green beam)

J3 (4-pin mighty mouse connector) = M6 (green + IR beam)

J4 (4-pin mighty mouse connector) = M4 (IR beam)

J5 (4-pin mighty mouse connector) = M14 (IR beam)

During assembly of the picomotor mounts, we are not sure if the 'verticl' and 'horizontal' axis of the picomotors are maintained (e.g. we did not know which of the picomotor was horizontal or vertical).

Also, the two QPD sleds are aligned, with each a single 25-pin connector (D1000231), are mounted in the connector brackets. There are two QPDs per 25-pin connector, one for the green sled adnd one for the IR sled. The QPDs are ordered such that QPD1 is the first QPD the beam will be director to (by a beam splitter), while QPD2 is the last QPD on the sled.

The connectors are mounted with pin-1 on the top right corner, with the connector mounting bracket on the primary mirror side of the breadboard. (photo of the bracket)

25-pin IR QPD connector mounted on the lowest position

25-pin GRN QPD connector mounted on the middle position.

Here is a photo of the top view of the breadboard with the cables routed and clamped on the breadboard. The 'ETM Side' is on the right.

The only cable missing on the breadboard is for the bam diverter (the larger structure on the bottom right on the breadboard).

Matt and Bram

I inherited this shift from MichaelR at noon.

- DaveB and JonathanH at EY installing WiFi

- HEPI actuators being craned in LVEA

- Bob Hamilton of Bob Rhodes HVAC arrives for H2 PSL work

- Work continues by SUS stand in LVEA

- L1 OMC shipped this morning from LLO

- Laser hazard restored in LVEA by ~15:30 for squeezer work
 

(Corey, Eric)

While we had access to the popular Main Crane, (4) Horizontal & (1) Vertical Actuators were craned and bolted (not torqued) into position on the BSC4 Piers.

The structure of the sections/tasks will be changing to better reflect the system.  Currently most entries reside under the 'IFO and SubSystems' section with sub-system specific tasks.  These will be rearranged to separate out the H1 & H2 IFOs, test stands, and general site issues.

As such the new structure will be added today (Friday the 16th).  The actual migration will take place early Monday (I will aim for 8:15-8:30am Pacific).  The old section and task names will be removed as part of the migration.

You may continue to use the old section and task names today if you wish.  Please begin using the new ones before Monday morning.

No existing entries will be lost, they will simply be migrated to their new locations.

No chronology will be lost.

No downtime will be involved.

This will be done in the near future at LLO as well.

This email will be posted in the aLOG.

New structure:

Section: Logbook_Admin
Tasks: 	Bug
	Feature Requests
	General

Section: LHO
Tasks:	General
	FMCS
	VE

Section: H1
Tasks: 	AOS
	CDS
	COC
	DAQ
	DCS
	FMP
	IOO
	INS
	ISC
	PEM
	PSL
	SEI
	SUS
	SYS
	TCS

Section: H2
Tasks: same as H1

Section: X1
Tasks:	SEI
	SUS

-- 
Jonathan Hanks
General Computing Sys Admin
LIGO Hanford Observatory

Finish swapping out SAT field cables from rack to SAT units for ITMY and FMY. Old cables removed.

F. Clara, J. Garner

(Corey, Greg, Jim)

This balancing encompasses two days.  We balanced the system by monitoring digital voltmeters connected to each Corner's mini-rack.  For the Stage1 CPS's we aimed for voltages under +/- 0.200V, and for the Stage2 (Fine) CPS's we aimed for voltages under +/-0.500V.  A negative voltage connotates a small gap w.r.t. Target Face, and a positive voltage obviously means a bigger gap. 

On Wed, we primarily addressed Stage2, and then stopped since we didn't have enough weights, and needed to consult MIT with our progress.  The notes for Wednesday's work is attached.  For today's work, we focused on finishing out Stage1 Balancing.  After the entire system was balanced we also noted mass placement for the system. 

Finishing Off Today's BSC8 ISI Balancing:

• Initial state:  LOCKED Stage1 & UNLOCKED Stage2
• GAPPING CPS Stage1 & Note values:

Corner1
Stage1
H:  -0.032 V
V:  -0.062

Corner2
Stage1
H:  0.016
V:  -0.115

Corner3
Stage1
H:  -0.021
V:   0.055

• Unlock Stage1, Balance, & Note All CPS's:

Corner1
Stage1
H:  -0.062
V:  -0.014
Stage2
H:  0.066
V:  -0.299
Corner2
Stage1
H:  0.115
V:  -0.015
Stage2
H:  0.103
V:  0.144
Corner3
Stage1
H:  0.190
V:  0.033
Stage2
H:  0.432
V:  -0.380

Mass Distribution

Below are the masses used to attain the current balanced state:

Keel:
(26)D0903136
(2) -1200 Type6

Optical Table:
(6) Trim Mass Damper Assys

CORNER 1
Stage1
Wall:  D0902614, -2615, -2616Type1 , -2616 Type2, -2616Type3, -2616Type5
Side Wall:  -2612
Stage2
Walls (D0701200): (1)Type1, (3)Type2, (1)Type3, (3)Type4

CORNER 2
Stage1
Wall:  D0902614, -2616Type1, -2616Type1, -2616Type2
Side Wall: -2612
Stage2
Walls (D0701200): (2)Type1, (1)Type4, (1)Type5

CORNER 3
Stage1
Wall:  D0902614, -2615, -2616Type2, -2616Type5
Side Wall:  -2612
Stage2
Walls (D0701200): (1)Type2, (1)Type6
 

The dome was replaced on the chamber today and FTIRs were sent off to JPL along with an appropriate note regarding the priority of the samples. Needed items were staged back at the corner station for HAM-7/8 ICC. Door blanks will be replaced tomorrow. For the record, actual in-chamber work at BSC-6 required 7 work days.

The first two serial cables connected together from the break-out box to the dust monitor at location 6 (in the H1 PSL diode room) had become disconnected. I reconnected them with extenders. The dust monitor had been swapped earlier as part of the troubleshooting.

Where a comment to an aLOG is attached under the main entry, the formatting that a user enters into the comment is not retained (carriage returns, tabs, spacing, etc.). However, the redundant separated comment (that appears at the top of the viewing page) does contain all formatting. This fix will be imperative once the requested feature of Comments Only Showing Up Under the Main Entry is implemented.

If you type an entry into the "Quick search" box and hit enter, the page refreshes instead of executing a search. You have to click the search button to actually do a search.

When hitting "enter" in quick search, it doesn't execute the search, it just returns the entire alog.