This morning I adjusted the I-Q balancing of all the demodulators at the AS port (i.e. the ones in ISC R3 rack).

I did the same technique as described here. I did not turn on any of the whitening stages. The gain of the whitening filters were set 21 dB (although I am not sure if this is close enough for the future operational condition.) except for ASAIR_B_RF18 which I set the gain to be 45 dB. The beatnote were ajusted such that they are in between 40-50 Hz. Since the amplitude imbalance were typically smaller than 0.5 % or so, I did not try to correct the amplitude imbalance. Therefore only parameters I adjusted were the phase difference btween the I and Q signals. Here are the results:

= = = 

RichardM, PeterK

A few pictures were taken of ETMY in order to see if any dust particles could be spotted prior to Rai's vacuum test.  The pictures were taken from the viewport under the beam tube as this appeared to offer the best view and allow some manner of support for a camera.  A number of shots were taken with a 30 sec exposure.  The illuminator was on for these photos.

Even when zooming in on the images, it is not clear if there are any dust particles present because of the images becoming pixelated.  One of the images shows a black spot near the centre of the optic but I think this is an artifact of using a smaller aperture.

Alexa, Sheila

We went into the PSL to understand the calibration of the power into the chamber.  The first step was to remove temporary half wave plate  alog 12710.this changed the splitting ratio for the monitor PD, causing our monitor to not be accurate. .We also updated the calibration of the rotation stage, the max power we set to 20.7 Watts based on a measurement with the water cooled power meter head before the rotation stage; we found that the minimum power was 17 mW at an angle of -24 degrees so we also updated those values.

As a check we requested 1 Watt from the rotation stage, we measured 1.12Watts, and our monitor readback report 1.15 Watts.  We have left this setting, the light pipe shutter is closed.

model restarts logged for Wed 06/Aug/2014
2014_08_06 02:01 h1fw0

unexpected restart of h1fw0

Minutes from Morning Meeting

• LVEA transitioned to SAFE this morning before the meeting
• Vacuum Status at 1e10-4
• commissioning work:  PSL power adjusted, IMC locked on 0:0 mode.  Next up:  WFS work
• BS/ITM Oplev work ---could be a full day (will transition to HAZARD after assessing state at lunch time)
• Apollo:  CR &other stuff out of beer, reinstall stairs, HAM6 viewport installed
• Chasis work in Beer Garden continues (Richard's Team)
• EY:  Rai's ionization discharge work continues
• EX:  krishna slow transfer function measurements for Rotation Sensor.  Would be nice to have purge air off for these measurements. 
• EX:  Could possibly begin pump down today
• Can start shutting off un-used cleanrooms (except HAM5/6 & Test Stand)
• LN2 delivery today

Safety valve set points @ 5 x 10-1 torr -> will change to nominal value of 5 x 10-2 torr tomorrow

(Borja)

Several issues has not allowed me to drive the ETMY ESD until late afternoon today. At this point I was able for the first time to test, with real data, the automation code for the ESD charge measurements develped at Livingston. I did have previously adapted it for Hanford's slightly different configuration but this was the first time I was able to test its results. Unfortunately the automation on the injection, data request and analysis is not robust, not allowing for the whole process to finish several times. Also the code does not take into consideration conversion factors on the V BIAS from Voltage to counts and viceversa. I assume this is taken care in Livingston outside of the code but certainly that solution does not make it universal.

Looking at the procedure with Rai I realized that we have to be careful on the level of the driving signal amplitude to be below the minimum V BIAS used in the analysis otherwise linear approximation assumptions in the methodology are no longer valid.

Rai is leaving on Saturday and we need to apply his discharging technique before then (optimally tomorrow). Before this takes place we need to have some ESD charge measurement data so that we can compare with data taken after the discharge and see the effects observed. This time constrains has made me decide to do the measurements manually tonight. I may be able to run the automation code afterwards and compare it tomorrow with the manual measurements but this may not be possible. See manual measurements in the attached document.

Today I checked the RF level at various points in the ISC R3 rack (which is the one by HAM6, containing the AS-related demodulators) as a part of the DRMI preparation.

The next thing we need to in this rack is the I-Q balance adjustment for all the demodulators. This is something we can do before the table is moved in place.

RF level re-adjusted:

I have adjusted the RF level by inserting or changing RF attenuators such that the power at the input of every RF device is at 10 dBm except for the WFS quad demodulators. Sine those quad demodulators have a 4-way splitter in the box, they did not have to be as low as 10 dBm. So I simply did not put an attenuator for their paths. This gave me about 13 dBm at the inputs of all the quad demodulators.

Two RF cables replaced:

When I was checking the RF level, I found two wacky cables which showed anomalously high loss. One of them was pretty obvious -- the SMA connector part was the cause and stress on the connector changed the amount of the loss. So I simply cut the SMA connector part off of the cable and put a new SMA connector. This fixed the issue. In the other cable, I could not identify what parts were giving the high loss. However Filberto replaced both N-connector and SMA connector for me and this fixed the issue. I put them back in the rack and confirmed that the RF levels were at the expected level. Good.

As suspected and reported earlier while doing coil balancing (cf logs 1 and 2), SR2 M2 UL actuation appears to be non functioning. An in-chamber cable would be disconnected.

First, in order to confirm the problem, an old range-of-motion matlab script was resurected and used : it ramps positive then negative offsets (+/- 132000 cts) to each coils of M2 stage, and looks at the motion response. The plots of the results are attached and are clearly showing a difference with the UL response, moving less than 0.1um whereas the other osems show more than 1um range of motion. 

Then, to see if the problem was in-chamber/in-air, the resistance of the four coils of middle mass was measured at the satellite box and the in-air side of the feedthru - in both cases a breakout board was used, plugging it to the sat-box side of cable H1:SUS_HAM4-31 in the first case, and the HAM4-D6-3 feedthru connector in the second case (wiring ref : D1000599). Measurements with the multimeter at the two ends roughly gave the same results described below :

LR (pins 1-14)~= 17 Ω
UR (pins 4-17) ~= 17 Ω
LL  (pins 7-20) ~= 17 Ω
UL (pins 10-23)  = ∞ Ω

The resistance of UL shows the circuit is open between the flange connector and the coil, somewhere in the chamber.

SR2 was tested by Stuart after HAM4 doors closeout and wasn't showing any actuation issues.

Since Borja balanced the coils with a non functional actuator yesterday, I will run undamped M2-M2 TFs overnight using the gain values he found, and see how the dynamic response is affected.

Stefan, Sheila, Alexa, Kiwamu

We locked the IMC on a 00-mode this evening. The next step is to wait for the pump-down to finish and  perform a ring-down measurement to check if the absorption is not too high.

Preparation:

After talking to Mike and John, we agreed that we can do an IMC-related interferometry with a low power laser even though we are not yet on the turbo pump.The pressure at that time was below 10 torr according to John. The PSL power was decreased to 56 mW by using the rotational stage because we needed to be lower than 100 mW which is the limit for the in-air IMC locking. We then locked the rotational stage such that we won't accidentally exceed the limit. Also I had a chance to talk to Dennis about this laser power issue and he agreed that we can do some interferometry with a low power laser. Thank you for the discussion, Mike, John and Dennis !

Initial Alignment:

To recover a good alignment, we started from the PZT input pointing. We checked the spot position of the scattered beam from the HAM1 viewport, projected on the wall of the PSL enclosure. The beam was lower than the previous marking, by 5 mm or so. We then touched up the input PZT to bring the beam back to the previous making position. The PZT count in PIT had been 679.6 and after this alignment it became 683.6 counts. The we checked the alignment on the table, but surprisingly, we did not have to touch any optics at this point. This means that Bubba and company placed the IOT2L table very precisely, maybe with a precision of a few mm. Thank you, Bubba !

We then placed an analog camera in the transmission path because the GigE was not functioning for some reason. At the beginning the alignment seemed off largely in pitch. So we started tweaking the things. Starting with the PZT again, we could not get a decent 00-mode. We decided to touch the MC mirrors. We touched MC2 in pitch and was able to see a decent 00-mode flash. Good.

Locking and further tweak:

As soon as we turned on the IMC board with a high gain, it grabed a 00-mode. We then did a futher alignment  on MC2 to coarsely maximize the power-buildup. The visibility was 75 %. In lock, the reflection was about 40 and unlocking We then re-centered the WFSs beam by hand on the table and tried the ASC servo. But, after an hour of struggling, we realized that the MC2 TRANS QPD did not have a good enough signal-to-noise ratio. So we need to crank up the laser power once the pumping is over. This is now preventing us from engaging the ASC loops.

An enigma:

Signals from the IMC_REFL_DC signal occasionally behaved quite funny -- the REFL_DC signals went up by a facto of 5 or so, while the WFS DC signals remained the same. At this point, we have no idea what was going on. We will investigate a bit more tomorrow.

(Alastair and Greg)

Over the last three days we have worked on three separate areas:
1) Bonding the Wavelength thin film polarizers into new mounts
2) Working on the X and Y tables
3) Testing laser #20510 that arrived today from Caltech

1) Thin film Polarizer Bonding 
The thin film polarizers from Wavelength, of which we use 4 per site, had pretty flimsy mounts where a plastic screw was used to hold the optic in place. This resulted in a tendency for the optic to move around causing quite large angular changes that could not be accommodated with our optical layout. A new design of mount was made and here we bond them into place.

Initially we measured the pitch of the old mounts for each of the 4 polarizers.  We measured the initial position of the optic, then tested how far it could pitch up and down. 
#1) Initial position 26mRad, Highest pitch 31mRad, Lowest pitch 26mRad 
#2) Initial position 18mRad, Highest pitch 31mRad, Lowest pitch 13mRad 
#3) Initial position 9mRad, Highest pitch 12.5mRad, Lowest pitch 9mRad 
#4) Initial position 5mRad, Highest pitch 5mRad, Lowest pitch 5mRad 

The optics were then removed from their old mounts and were drag wiped. First contact was applied to the front surface to protect it during mounting. We then bonded the polarizers to the new mounts using RTV Silicone. The silicone was applied with a syringe to three points on the mount, and using 5mil spacers the optic was held with a set spacing to the mount. After 24hours (listed as max strength setting time for the RTV) the spacers were removed and the pitch of the newly bonded polarizers was measured. The mounts have 1/4-20 threads top and bottom, and we measured each polarizer both ways up to be sure that we don't have any issues with how parallel the faces are, and since the optic is on a post on a table we could also have some error from this also which we would see by checking the polarizer both ways up. Serial numbers below are those stamped on the new mounts 

#001 Writing right way up 1.5mRad pitch Writing wrong way up 1.5mRad pitch 
#001 Writing right way up 2.5mRad pitch Writing wrong way up 6.3mRad pitch 
#014 Writing right way up 15mRad pitch Writing wrong way up 11mRad pitch 
#008 Writing right way up 5.6mRad pitch Writing wrong way up 5.6mRad pitch 

Polarizer #014 showed a pitch that was outside what we think acceptable (requirement 7mRad), and was then removed from the new mount and rebonded. Since we have spares we used a new mount to rule out problems it. The new mount is #015. This polarizer was tested for pitch after 4 hours of curing, but the RTV was found to not be fully cured. It was reset to the correct height and will be left the full 24hours before retesting. 

2) Work on X and Y tables 
The X table initially had a full version T1200007-V11 of the layout (not using masks in flipper mirrors). The Y table had most of the layout roughly in place for T1200007-V12, though mostly not aligned. The two polarizers from the power control stage had been removed from both tables for bonding. 

We began by turning on the laser on the Y-arm table and aligning through the first polarizer and AOM, up to the power control stage. The extinction ratio at the first polarizer was measured at ~100:1. The AOM was checked to have a 1st order efficiency of >90%. No alignment was done after the power stage since polarizers were not available. However we did go through and mount the few missing optics in roughly the right place, so the table is complete but not aligned. 

The alignment on the X-arm table should have been correct up to the power control stage, but was found to be off after the first mirror. The mount was checked and it was found to be held securely in place with the actuators locked and the mirror firmly secured. The laser mount was also checked and found to be secure. It's not clear how this had moved, but by the time the beam reached the rotation stage it was back in the correct place, so we hypothesize that the first mirror was knocked during the previous alignment and prior to its actuators being locked. We realigned the beam through the first polarizer and AOM, checking the extinction ratio of the polarizer and the efficiency of the AOM (similar values found to the Y table). The alignment was again performed up to the power control section but again the lack of polarizers meant we could go no further. This table has all its optics, but they still need placed and aligned for V12 layout (some small changes were started, but most optics have not yet been moved). 

3) Testing of laser #20510  
The laser that arrived from Caltech was found to have damage to the RF driver from shipping. There were three substantial pieces of damage : a dent on one side where the end of the laser had hit, and both sides of the driver had bent water connections. There were no signs of damage to the laser (you can see the linetracker on the end is straight in the photo attached, though it had clearly been hit into the RF driver) and the outside of the Pelican flight case shows no damage either. 

We decided to test the laser immediately so that any repairs can be carried out. The laser was tested in the squeezer bay at the end of the LVEA, and required power, RF, water cooling etc to be put in place. 

Using the driver for the laser we immediately found problems, with a maximum power output of 40W. It was found that one of the fuses on the RF driver had blown (clearly burned out and not just broken). We replaced it and immediately the fuse blew again. We then replaced the driver with a unit from a different laser. The power output was ~50W at 95% duty cycle (using synrad controller this is maximum output). The CW output should be in excess of this and matches the specs for the laser. 

The RF driver will need to be returned for repair and we will be looking into improving the packaging for the lasers. There are two more lasers currently at Access having their water cooling problems repaired, and Greg may drive out to pick these up just to avoid more damage.

J. Kissel, G. Valdez, R. McCarthy

I grabbed the recently found GS13 578 with the busted locking mechanism (see LHO aLOG 12932) from EX, opened the can, and inspected the locking rod and gear mechanism inside the can. I didn't find any obvious obstructing stuff that would prevent the locking mechanism from functioning -- it just seems as though the main gear controlling the locking pin has ceased. Without further dis-assembly, with which I'm uncomfortable doing, there's no way to assess the problem further.

While I had the can open, I converted 578 from horizontal to vertical configuration -- a much more robust configuration if we don't have a locking mechanism. Unfortunately, during the process, one of the three fragile metal tabs that engage the corresponding vertical spring (already pretty mangled when I got it) broke in the upper-left corner such that the screw-hole is no longer whole. Luckily there was still enough of the tab left, that I could put the tab in place, and tighten down the square nut enough that it held the tab engaging the vertical spring. 

Attachment Captions:
Pg1 - A picture of the corner of the broken tab, showing the vertical spring engaged regardless of the missing chip.
Pg2 - The bottom of the locking mechanism, showing the locking knob gear, and the main locking pin gear. The gears are engaged, and show no signs of damage.
Pg3 - Looking under the proof mass, at the locking pin. Nothing seems to be interfering.
Pg4 - A shot of the top of the instrument, for ID.

After restoring the can, I increased the tension on the vertical springs to bring the proof mass up into the locking containment ring, as the locking mechanism would do. It's *lock* locked, but it's held against the retainer ring. In this configuration it can now withstand a few g's without bouncing around, and there's much less danger to the fragile horizontal flexures (still the stock flexures, as these were installed before the Stanford team innovated better ones). Note, this GS13 also has a LIGO custom pre-amp (D050358) in it, so the Q is a sludgy 5-ish (ref. T0900457), which is also good for robustness.

From here, I suggest one of two courses of action:
(1) Replace the stock horizontal flexures with the rugged Stanford flexures, such that this GS13 doesn't need a locking mechanism any more. We should have at least a set of these at LLO left in the spare stock.
(2) Send the instrument back to GeoTech, and have them repair the instrument. If so, then then can also replace the broken vertical spring tab.

I'd say the likelihood of instrument failure if shipped it it's current condition is pretty high. 
I'd say swap out the flexures, but will discuss with the SEI/PEM/CDS teams. 

For now, the instrument resides in my office, leaving the summary of these eLIGO PEPI Feed-Forward GS13s as
S/N     Config      Current Location
568        V        EX, in change-room, by bench
574        V        CS, In my office
578        ??       EY, on change-room racks
584        ??       EY, on change-room racks

Similar to HAM2 & HAM3 but the shift in position wasn't enough to trip the ISI but the outputs were decidedly large.  So, I reset the target position to the free hang position.  Unable to safe.snap as SUS folk are using platform. 

model restarts logged for Tue 05/Aug/2014
2014_08_05 10:16 h1hpietmy
2014_08_05 10:16 h1iopseiey
2014_08_05 10:16 h1isietmy
2014_08_05 10:20 h1iopsusey
2014_08_05 10:20 h1susetmy
2014_08_05 10:20 h1sustmsy
2014_08_05 13:02 h1fw1

Unexpected freeze of h1seiey, unexpected dolphin glitch of h1susey during recovery, unexpected h1fw1 restart.

model restarts logged for Mon 04/Aug/2014
2014_08_04 12:39 h1lsc
2014_08_04 12:42 h1lsc
2014_08_04 12:45 h1broadcast0
2014_08_04 12:45 h1dc0
2014_08_04 12:45 h1fw0
2014_08_04 12:45 h1fw1
2014_08_04 12:45 h1nds0
2014_08_04 12:45 h1nds1

no unexpected restarts. LSC ipc work plus related DAQ restart.

J. Kissel, R. Schofield

I discovered a lonely, forgotten, disconnected GS13 hiding under BSC9 (H1 ETMX) chamber today. I attach pictures. 

Things that Robert and I can surmize:
- It's serial number is 574, and has a "property of the USGS, greater than $5k" sticker on the side with the number G12077 and a bar code.
- It may have been used for S5/S6 feed-forward studies (Will check with Mike, Keita, Richard)
- Ski may have purchased it, given the bar-code on the side (Will check with John)
- It's a 2005-ish era model, based on the color of its can and unfinished look of the feet.
- It's currently configured as a horizontal
- It claims of a broken locking mechanism, but after a few turns the mass seemed locked enough for transport
- It's functionality is unknown.

Finder's keepers ...