Upon returning from vacation I was annoyed by the fact that launching firefox as controls from any of the cds workstation takes forever (more than 5 minutes). I eventually found that the firefox command was overridden by a launcher script (/ligo/home/controls/bin/firefox) that rsyncs user profile to /tmp/somethingsomething, and unfortunately it copies seemingly useless things like Cache.Trash******* that contains over 3.8 million files!

Cache.Trash seems to serve some purpose when firefox exits abnormally and tries to recover session information, but somehow it keeps growing because of firefox bug. I just deleted Cache.Trash.

In addition, though I don't know why you want to rsync your user profile to /tmp, I changed the launcher script so rsync excludes Cache.Trash (or anything starting Cache). I don't care if the previous session is not recovered.

One of the goals of the OAT was that the residual arm motion measured by the green beam, with the VCO to arm offloading, is about 10 nm or so for f<0.5Hz.

Attached is the calibrated residual motion in nm/sqrtHz. Solid lines are with both ISI isolated (non-aggressive crossover, without Trillium), and the dashed are with both ISI only damped. These are not a true A/B comparison (different lock stretches, different seismic level, only 7 averages) but are good enough to show you some ball park numbers.

1. Even though the isolation helps greatly at 1Hz, it makes a huge peak at about 40 to 50 mHz with the RMS of about a micro meter. This might or might not be larger than expected, but as I understand from Vincent we expect some amplification at this frequency.

2. With or without the isolation, 0.46Hz peak is also big. Isolation might be helping a factor of 2 or so but we need a factor of 20 or more.

3. Though it's outside the scope of the stated OAT goal, 1Hz peak is not negligible. Without isolation, this should be reduced by a factor of at least 5 or so.

Vincent might be able to refine ISI further, but we shouldn't expect HEPI/ISI alone to bring the residual RMS down to 10nm level (or even 50nm for that matter, stated goal of OAT for HEPI/ISI is 200nm RMS and we're already quite close).

Regardless of the ISI isolation, we need a more aggressive VCO offloading to the length. Right now VCO is only offloaded to the HEPI, and the UGF of this path is smaller than 10 mHz. We need to use another path to the ETM and/or ITM suspension if we want a larger UGF to suppress e.g. 0.46Hz peak.

The reason why no work has been done for this for a long time, I think, is because there was a huge POS to PIT coupling when you drive M0. What's the current status of drive diagonalization (don't confuse this with sensing diagonalization)?

[Mike R., DF]

We have placed a number of mirrors on the H1 PSL table to divert the beam after the periscope to the FI testing and alignment area. This was done by:
a) moving three 1" IO_AB mirrors from their intended to new temporary positions
b) placing three 2" mirrors from the eLIGO POY and POB on the table.
The full setup will also require an HWP to control the polarization of the beam sent into the FI, and (maybe) a lens to get the correct beam size at the location of the FI.

Note: the schematic diagram below does not properly identify the identities of the newly placed/moved mirrors, only their positions.

This morning Deepak brought several parts for the IO Faraday Isolator which had just come out of the bake oven, and I began putting the FI together. The assembly was performed in the H2 PSL enclosure, and so far does not include any optics, so it really is a "fit test". Everything fits, although some mods have to be made compared to the FI mechanical assembly E0900301-v5:

1. Same as at LLO, the removal of aluminum shims from between the rotator magnet and the magnet base resulted in magnet not being solidly held by the omega-shaped clamps. Same as at LLO, this was solved by inserting the same shims between the magnet and the omega-clamps on the upper side of the magnet.
2. The spacer plate is much thicker at LHO, and so 1" long screws are way short for attaching the magnet assy and spacer to the breadboard. 2" long screws work better, and I'll need to get more of those from the SUS people tomorrow.
3. Same as '2' for the HWP picomotor assembly and insert.

This is close to what can be accomplished without inserting the optics.

Elli and I took transfer functions of the OLTF using common mode B. The optimal gain setting was found to be -14. This results in a UGF of approximately 10.4 kHz while keeping the resonance at 42 kHz below 0 dB (maximum about -2 dB).

At higher gains (-10, -12, -13), the 42 kHz peak was consistently greater than 0 dB.

I ran some ring heater measurements this morning. I incrementally increased the requested current from 0mA to 29mA in units of 1mA. The power radiated from the ring scales as the current squared. We were radiating aorund 6-10W at 630mA requested. With these measurements we would've been radiated no more than ~22mW.

The calculated resistance of the ring heater is 33.93 Ohms for Segment 1 and 34.06 Ohms for Segment 2.

There are some offsets and gain settings between the requested and measured currents that I need to fix.

PR2 was installed in HAM3 today, and traveled well on the Genie and Arm.  It's sitting against it's cookie cutter, and dogged down overnight.  The crew was Kurt Buckland and Scott Shankle, as well as Deepak and I

During course of R&Ring center down-facing feed-through flange and extending purge air header beneath HAM1,2.  

Noisy day, which permited lots of noisy activities.

• Apollo crew moved cleanroom around in the LVEA with crane, very noisy
• Aidan to End-Y to calibrate HWS, see entry for more information
• Floor work continues at End-X
• Electrician visited all stations
• Late delivery, from NY, 4 skids to large equipment access bay area.
• Apollo used Big Red to move an item from OSB to staging building
• Patrick setup a dust monitor around HAM01 area

[Jax, Aidan, Elli]

This morning we calibrated the lever arm of the HWS. We added a beam splitter (CAL-BS) into the optical path to hit the HWS CCD with two beams (REFL and TRANS) at ~ 10mrad to each other. We removed the Hartmann plate from the sensor and recorded the resulting interference pattern on the CCD. The spatial frequency of the interference pattern allowed us to determine the exact angle between the two beams, 9.86mrad, with a precision of approximately 1:500. Next we replaced the Hartmann plate and measured the Hartmann sensor spot pattern of each beam separately by blocking first one and then the other beam. We centroided the spots and determined the mean centroid displacement, 8.507 pixels. Knowing the measured angle, the pixel size (12E-6 m) and the spot displacement, we determined that the lever arm distance (between the Hartmann plate and the CCD) is 10.35 +/- 0.03mm.

The data is attached. Also attached is an optical layout showing the additional beam splitter producing the reflected and transmitted beams.

We made certain to remove the beam splitter and check the final alignment of the HWS system was restored to nominal before closing up the ETM ALS table.

The reference lever arm that has been used before now is 10.0mm.

Replaced the fuse for the dust monitor in the clean room over HAM 3 (LVEA location 15). Restarted the EPICS IOC.
Added a dust monitor in the clean room over HAM1 and 2 (LVEA location 9).

Collected as much serial number as possible on the nearly completed HAMISI#7 (just a few remaining tests for it).  There was one item I was not able to get, namely the a Flexure; it was oriented in a way that made its s/n NOT viewable (waiting to see if someone jotted this info when they built the system).  Below are all the other s/n's:

Stage0:  014

Stage1:  010

Optics Table:  009 

Corner1

Actuators

• H1:  179
• V1:  097
• H1 Cable:  S1104095
• V1 Cable:  -6677

GS13s

• H1: 009
• V1: 003
• Pigtail Cable:  -4677
• Extension:  -4700

L4Cs

• H1: 006
• V1: 041
• Pigtail Cable:   -4681
• Extension:  -6651

CPS Sensor

• H1: 12009
• V1: 12025

Flexure:  -- not viewable, installed upside-down :(

Spring:  030

Support Post:  031

Corner2

Actuators

• H2:  178
• V2: 118
• H2 Cable: -4098
• V2 Cable: -6682

GS13s

• H2: 061
• V2: 050
• Pigtail Cable: -4679
• Extension:  -6656

L4Cs

• H2: 114
• V2: 052
• Pigtail Cable:  -4687
• Extension:  -6650

CPS Sensor

• H2: 12012
• V2: 12016

Flexure:  046

Spring:  041

Support Post: 017

Corner3

Actuators

• H3: 176
• V3: 007
• H3 Cable:  -6675
• V3 Cable:  -7761

GS13s

• H3: 078
• V3: 053
• Pigtail Cable:  -4686
• Extension:  -4705

L4Cs

• H3: 090
• V3: 0014
• Pigtail Cable:  -4680
• Extension:  -4706

CPS Sensor

• H3: 12036
• V3: 12030

Flexure: 040

Spring:  045

Support Post:  032

B. Bland, J. Garcia, J. Kissel

Attached are plots comparing the recent H1 SUS PR2 Phase 2B measurements against other HSTS in various stages (completing the data package) in order to give a final answer on Phase 2B testing.

As of this entry H1 SUS PR2 passes Phase 2b and is go for install into HAM3, with the following caveats:
(1) Late in the game, the assembly team found an IR filter is missing on an M3 (Bottom) stage AOSEM. The spectra comparisons show that there's little-to-no difference in the response of sensor, i.e. it's functional (as far as you can tell in the noisy chamber-side environment). Regardless, the assembly team are aware of the problem, and will replace that AOSEM once in chamber, as there's plenty of room to play around in there, and it's a simple fix.

(2) It's a long story (so I'll save it for a subsequent comment to this log), but we discovered the same small T to Y cross-coupling at 1.1 and 2.05 Hz on PR2 as was recently discovered on X1 SUS MC3. At the time, (we thought) X1 SUS MC3 was the only SUS that had such cross coupling, and (we knew we) still had lots of chances to debug the issue before install, so we approved his Phase 1b results and agreed to move forward. However, due to the hectic/scattered measurements and turn-on blips of getting the HAM SUS up and running at LHO, the cross coupling in H1 SUS PR2 (formerly X1 SUS PR2) has fallen under the radar up to this point. So, in light of several things:
- (As in seen in the attached TF comparisons, specifically pg 2, the M1 to M1 T to T TFs), ONLY X1 SUS MC3 and H1 SUS PR2 show this particular cross coupling, out of Nine other HSTS that have been built project wide (again further clues, a better zoom, theories, and conjectures to come).
- We will move X1 SUS MC3 chamber-side, and the install team will spend an extended amount of time identifying/debugging the problem where there's plenty of room, and less pressure. Once the problem is solved, they will retroactively make the same changes to H1 SUS PR2 in chamber, where (at least in HAM3) there's a comfortable amount of room to make adjustments.
- Again, the coupling is small, and goes away with damping -- the concern is the model, which we use extensively to predict motion estimates, may not be as accurate.
 
Ease of later documentation, the individual measurements that compose the rest of the package are aLOGged here:
Damping Loops OPEN M1 to M1 TFs: LHO aLOG 3851
Damping Loops CLOSED M1 to M1 TFs: LHO aLOG 3855
Amplitude Spectra of All Stages: LHO aLOG 3861

The overview medm for the TMTS suspension was modified today to correct mislabled channels.  A DC align medm part was ported over from the QUAD medm directory for use in setting DC offsets on the TMTS suspension.  All changes were committed to the cds_user_apps SVN.                                                                         

A report on the measurements of the hydrocarbon residual gas at the y end has been posted
on the LIGO DCC with a document number LIGO T1200395-v1. The hydrocarbon pressure,
now with all the advanced LIGO components in the chamber, raises concern. The data and the
suggestions of actions to take are discussed in the document.

Attached are plots of dust counts > .5 microns in particles per cubic foot.

In order to complete the individual data set for H1 SUS PR2's phase 2B testing, I attach the amplitude spectral densities of all stages of OSEMs. Tough to determine anything from these plots:
 - there's so many dang plots,
 - one is only comparing damping ON vs OFF, so you're only looking for "do the damping loops
       - Damp the resonances
       - Add any unexpected additional noise at any stage"
but given those limited criteria, the answer is "looks fine..."

Stay tuned for comparison with other spectra and a more concrete/final answer.

• Prep work for installing PR2 by HAM3
• Linoleum installation at EX, expected to continue through this week
• Fire alarm drill
• Elli, Jax, Alberto and Bram working at EY at different times of the day, working on one arm test
• Ken working on electrical at EX

It turns out that the Ring Heater itself can be used to measure it's temperature. The resistivity changes with temperature. We see the voltage change over the first hour when the heater is turned on: - this is due to an increase in temperature of the ring heater wire and a subsequent change in the resistivity of the nichrome winding.

I've estimated the temperature of the ring heaters over time using a nominal value of 0.00017 K^-1 for nichrome and the measured RH voltage from last week's test. You can see the results in the attached plot.

T0 = 1029555836 for Segment 1

T0 = 1029555847 for Segment 2

Voltage signals = H2:TCS-ETMY_RING_HTR_SEG1_V_MON_OUTPUT, H2:TCS-ETMY_RING_HTR_SEG2_V_MON_OUTPUT

Current signals = H2:TCS-ETMY_RING_HTR_SEG1_I_MON_OUTPUT, H2:TCS-ETMY_RING_HTR_SEG2_I_MON_OUTPUT

35W beam

We had trouble locking the FSS, and left it unlocked for several days. This was tracked down to the cable going to the FAST actuator and was replaced yesterday, and it's held lock since then, so it looks fixed. This is the reason for the drop in the crystal temperature.