(Borja)

First of all let us compile the chronological time information of the measurements and the discharge runs:

* Measurement 1 (before any discharge): took  place between UTC (2014-08-07 07:00:00) and UTC (2014-08-07 08:25:00).

* Discharge run 1: between UTC (2014-08-07 19:15:00) and UTC (2014-08-07 19:44:00).

* Measurement 2 (after 1st discharge run): between UTC (2014-08-8 18:00:00) and UTC (2014-08-8 19:30:00)

* Discharge run 2: between UTC (2014-08-08 20:48:00) and UTC (2014-08-08 21:38:00).

* Measurement 3 (after 2nd discharge run): between UTC (2014-08-10 00:00:00) and UTC (2014-08-11 02:00:00)

* Ion pumps in ETMY station was turned ON at UTC 2014-08-11 16:44:00. Notice from this entry that the ion pumps were OFF between discharge 1 and discharge 2 maybe that is why we see a charge reduction after each of these discharges. However the first charge measurement done above (before any discharge run) was done after several days of having the ion pumps on so why the ETMY had not bigger charge?

* Measurement 4 (2nd measurement after 2nd discharge run): between UTC (2014-08-11 20:31:17) and UTC (2014-08-11 23:00:00)

* Measurement 5 (3rd measurement after 2nd discharge run, this measurement is reported in this entry below): between UTC (2014-08-12 17:17:00) and UTC (2014-08-12 19:09:00)

Yesterday ETMY charge results (Measurement 3) were telling us that the ETMY was charging again since the 2nd discharge took place. What is charging the ETMY then? There are 6 mechanisms (that we can think of at the moment) that would cause ETMY charging and that they are different to the original MIT charging measurements, these are:

1)       Green light (through 2 photon process). MIT measurements did not include green light tests. But the green light is not on at the moment.

2)       The rubber stops on the reaction mass (seismic stoppers) with silica tips through silica to silica friction. The MIT tests did include these rubber stops and they did not observe any noticeable effect on the charging. Certainly they are installed in the ETMY reaction mass so they could be playing a role in the ETMY charging but it is hard to believe they would charge the mass so much in only 1 day.

3)       LED illuminators that were turned on from the first discharge run to see effect on the ETMY surface. They have not been turned off since (although there is no reason to keep them on at the moment apart of testing the current charging hypothesis). Again it is hard to believe that a broad angle not extremely bright LED can charge so much a mass in only 1 day.

4)       First contact. For the original MIT tests the masses were not covered with first contact. It is not secret that then removing the first contact layer the mass is charged. But no first contact has been applied or removed for the length of the discharging measurements.

5)        Discharge gage (aka 'cold cathod') this is the very low pressure sensor at the ETMY tank (BSC10). It operates in a similar fashion to an ion pump in which uses ion to pump out some air to sense the pressure. The amount of ions this one uses is considerably smaller than the ion pump (see below) however it is much closer to the ETMY mass.

6)       Ion pumps. This is a new game player. The MIT ion pumps were not used during their tests, so there is not measurement of their effect on the mass charge. Torsion experiments with fused silica fibres indicate that ion pumps do cause considerable charging. As I have describe above this is consisten with what we have seen. The ion pumps were OFF between discharge runs and in both cases we measured charge reduction on the ETMY, however after they were turned on they ETMY started to charge again (notice that the LED iluminators were ON during the 2nd discharge and never turned OFF yet so if it was the iluminator charging the ETMY then why we saw charge reduction one day after the discharge?). The only think that may  not agree with the ion pump being the charger is why the first measurement (Measurement 1) shows such small charging levels while the ion pumps were ON for days before that measurement took place?

However let's see now the results of today's measurement (nothing was changed respect to yesterday's measurement) there is only 1 day different in the measurement, see notes with the measurement values attached here as well as the plots of Normalized pitch and yaw deflection vs. VBIAS comparing measurements of today (identified in the legend as ending with 23) with the ones from yesterday (identified in the legend as ending with 22), I have also plotted a zoom version looking at the Veff (or zero crossing of the deflections. I show next the table summary with red for yesterday's results and green for today's. It is clear that the EMTY has charged considerably, which again seems to confirm the ion pump charger hypothesis.

Still there is one more variable in all this charging measurement game. Remember that one of the ESD quadrants could not be driven (quadrant LL) because its driving signal was going through the ESD low pass filter box, designed to filter the ESD BIAS frequencies above 1Hz, and the driving signal for these measurements is at 4Hz. This was solved before yesterday’s measurements, however are we sure that this change has not caused a different electric field configuration on the ETMY therefore making it incomparable with any other previous measurement? I had tried to run another measurement by bringing the cable configuration to the original case however between some power glitches bring the CDS down and affecting the suspensions controls at end station together with the higher seismic noise due to the sand storm has so far made this measurement impossible as the SNR is too low.

At the moment the ESD cables are as per the old configuration.

(Dan, Alexa)

Since the MC cavity length was adjusted, we repeated the MC cavity length measurement as described in alog 9679.

Data_refl9_short.txt is the data collected using REFL9. ArmCavityLength_v2.m is the script that determines the length given the zero crossing of the projection. The attached plot show the results with a linear regression included.

The cavity length is determined to  be L = 16.471698m ± 4um assuming 2 Hz accuracy. The 2 Hz accuracy comes from the accuracy of the IFR plus the extreme rattyness of the transfer function.

Compared to the previous measurement the delta L = L_old - L_new =  0.001914 ± 6um. This is very close to the expected 2mm reduction in length as mentioned in alog 12654.

If desired, we can repeat the measurement and include a zero crossing for REFL45 as well. However, we just wanted to make a measurement and get the result public...

Jeff K., Krishna V.

The pressure at the Turbo was 1.2E-6 torr this morning. The transfer function measurements have been less than convincing today. For now, I think d may be (+12.5 +/- 5) microns. I think cross-couplings (twist to tilt) may be introducing larger errors in this measurement than what I'm used to in the lab, where I have a much sturdier platform. The above value of d gives a displacement rejection of (9E-5 +/- 4E-5) rad/m. 

I have attached an ASD plot of 10k seconds of data from late last night/early morning, showing a very quiet ground, at the level of 0.1 nrad/rt(Hz). The blue curve, labeled tilmeter, is the measured tilt and the reference mirror curve is a ~ proxy for the autocollimator noise. We were hit with a dust storm around 4 PM this afternoon which produced lots of tilt noise, shown in the second graph, which was taken from ~5:25-6:30 PM. The noise near 0.1-0.5 Hz appears to be a factor of 10-100 worse. Wind speeds in that time frame were in the 30-40 mph range.

The pump has been turned off and I'm doing another overnight measurement. Tomorrow we will decide how much mass to add to try and reduce d as much as possible.

(Dan, Koji, Masayuki, Alexa)

We measured the HAM6 septum angle using a laser pointer. We confirmed that there was no observable vertical component to the wedge angle, and then proceeded to measure the horizontal angle. We pointed the laser pointer such that the retro-reflected beam off the surface of the septum returned approximately directly back. Then we measured the distance from the second reflection to this point. This distance was 17mm. The distance from the laser pointer to the septum was measured to be 360mm.

This gives: wedge horizontal angle: 17/360 * 180/pi /2 /1.45 = 0.93 deg

In the equation above the factor of 2 comes from the optical lever effect. Meanwhile the factor of 1.45 comes from applying snells law with the index of refraction for glass and assuming the small angle approximation (see attached drawing).

This measurement was not extremely precise, but was close enough to the expected value of 0.75 deg.

In the attached picture, you will see the retro-reflected beam, which is almost ontop of the outgoing beam, and the second reflected beam. We used the ruler below to measure the separation.

[Alexa, Masayuki, Dan, and Koji]

A beam found on one of the OMC QPDs. The fast shutter beam dump elevated.

- We went into the cavity and spent some time to align OM2 and OM3 to have a beam aligned to the OMC.

- We confirmed the beam is hitting the QPDA (short arm one).

- The beam is still misaligned (mainly in yaw) at QPDB.

- We want decent damping of OM1. OM1 has too much tilt and requires adjustment on OSEMs. We are working on this.

- The beam dump for the fast shutter need to be raised by an inch. Betsy provided us a set of suspension addon masses
to make the post longer. Using one of them, We successfullt elevated the height of the beam dump by 20mm. This was
enough to accommodate the beam including the possible wobbling of the mirror on the fast shutter.

Noticed that the turbo at the X-end station was also tripped off (electrical?), also its QDP80 -> Restarted and vavled-in -> resuming pumping at X-end

Jim, Cyrus, Dave

The large wind event was preceded by several power glithches which impacted on the DAQ and killed the front end computers.

After waiting to ensure that the power was stable again, we remotely (via management port) power cycled the FE computers at the end and mid stations and reset the MSR computers. Generally, computers not on the dolphin networks started themselves, some needed a power cycle. Once all the computers were all booted, they all started their models. At that point we discovered the Dolphin IPC in the MSR was non-operational. We suspect the glitchy nature of the outage put the Dolphin switches in a bad state. We stopped all models running on MSR computers attached to the Dolphin network (all but the PSL and SUSAUX). Power cycled the Dolphin switches. Rebooted the FE computers via front panel RESET button. Some models did not autostart and needed their "BURT_RESTORE" button pressed, which we did.

The DAQ was showing bogus data for slow channels (e.g. wind speed below 10mph when it was 50mph outside), so a clean restart of the DAQ was done. The NDS machines took many minutes before they got started, not sure why at the momemt.

Two systems started with a IRIG-B timing signal about 400 (should be 15), which then drifted down to nomimal over 20-30minutes. These were h1sush34 and h1iscey. We allowed these to become good rather than power cycle their IO Chassis.

Once the models were running, stable and had communication, I enabled the SWWD systems to drive the DACs.

Shiela is handling the recovery of the Beckhoff and PSL.

I opened GV2 and disconnected the leak detector -> noticed YBM and XBM turbos had tripped -> I assumed this was due to the gas bump from the gate annulus volume being too high for the, relatively low, safety valve set points of 5x10-2 torr -> Increased set point and restarted YBM turbo -> valved-in YBM turbo -> Increased set point and tried to restart XBM turbo but its QDP80 was also off(?) -> Restarted QDP80 but now turbo trips on vibration at about 75% rpm -> attempted to spin it up a few times but no luck -> This symptom has happened before and has been bypassed by introducing a gas load at the turbo inlet via cracking opening the "up-to-air" needle valve -> I didn't try this now will revisit tomorrow 

Pumping YBM, Vertex and XBM with YBM turbo tonight

Gerardo, Kyle 

Following John and Bubba's final-torquing of the under-torqued viewport on HAM4 (S. door, bottom middle) and also HAM5 S. door bottom left -> Kyle and Gerardo sprayed audible bursts of helium (up to 3 feet away or closer) at viewports, feedthroughs and all accessible flanges -> Helium baseline drifted slowly up from 9x10-9 mbar*L/sec to 3x10-8 mbar*L/sec during the test period (lots of helium sprayed)

This was not an exhausted test, some flanges were not accessible (light pipes sealed off with aluminized tape etc)., in most cases, flange leak test ports were not pressurized - though big leaks should have responded.  

I restarted the PSL after the power glitch. 

To do this I also had to reset the settings on the KEPCO power supply, and I reset the long range actuator.

When everything locked, the ISS difracted power was around 21%, I tried toggling the noise eater (nothing else on the ODC indicated a problem with the noise eater).  This didn't help, and I ended up adjusting H1:PSL-ISS_REFSIGNAL  to bring the diffracted power down to 9%

With wind gusts in the 70mph range, we are seeing spikes in the dust counts, most notable at EX with counts in the 100000s at 0.3um and 20000s at 0.5um.  Counts are also elevated in the LVEA around HAM3, HAM4, beer garden, and Y-arm spool but only into the 2000s at 0.3um and high 100s at 0.5um.

Replaced the batteries in the main cabinet of the  Mass Storage Room UPS.  Also replaced the backup control module.  This had gone bad a while ago so we were running without some redundancy.

This dust storm was fast.  Here are some photos of the approach.  Two power glitches preceded the storm (around 4:00pm).

EX: Switched filter box for ESD (Filiberto)

EX ISI TF running overnight (Jim)----> No banging on chamber!

Leak checking: y-beam manifold (Gerardo) & everywhere else (Kyle)

EY checking accelerometer locations for B&K tests (Arnaud/Tim)

EX calibration work (Paul, Jordan)

13:30 Greg turning on TCS CO2 laser in squeezer bay.

Justin refilled crystal chiller (Corey and Travis present as trainees)

PR3 oplev work beginning (Doug & Jason)

3IFO Quad work in the West Bay (Betsy)

13:54 Old conlog briefly being taken down (Cyrus)

14:23 Pablo to EY for ALS VCO characterization work

Dust monitor #15 (beer garden) alarm (13000 @ 0.3um but 0 @ 0.5um, check functionality??)

14:39 Tim and JeffK to EY to setup B&K measurements

15:03 Doug & Jason out of LVEA

16:00 Kyle opening GV2

16:25 Pablo done for the day

15:42 Paul & Jordan to EY installing voltage monitors

15:44 Hugh to EX restarting HEPI pump station

Two power glitches (~4:00pm local) from a giant Dust Storm that just hit us. Front ends died after the first glitch. Winds are gusting up to 70+ MPH. We're going to wait until the storm passes before beginning to restore everything.

Pictures are just before the storm hit.

Old alog 13299. Checked the two RF amp in ISC-R2 and found surprisingly high attenuators of 6dB and 4dB. Replaced the first with a 1dB and the second with a 2dB. 

New readbacks:

=== Rack ISC-R2 U38 ===
H1:ISC-RF_C_REFLAMP45M_OUTPUTMON = 22.6
=== Rack ISC-R2 U37 ===
H1:ISC-RF_C_REFLAMP9M1_OUTPUTMON = 22.4

The amplifier in the RF amp is nominally +12dB. 10dBm input will give close to 13dBm on each output at the tested 30 MHz. The slow readbacks should be around 22dB, typically no more than a 1dB off.

Readbacks for other 9 MHz and 45 MHz units in R2 went up accordingly. Some are now too high and need to be readjusted. WFS should be ok, since they use an RF splitter to distribute the LO to the 4 channels.

=== Rack ISC-R2 U18 (WFS REFL_A) ===
H1:ASC-REFL_A_RF9_DEMOD_LOMONCHANNEL_1 = 19.1
H1:ASC-REFL_A_RF9_DEMOD_LOMONCHANNEL_2 = 19.0
H1:ASC-REFL_A_RF9_DEMOD_LOMONCHANNEL_3 = 18.9
H1:ASC-REFL_A_RF9_DEMOD_LOMONCHANNEL_4 = 19.3
=== Rack ISC-R2 U16 (WFS REFL_A) ===
H1:ASC-REFL_A_RF45_DEMOD_LOMONCHANNEL_1 = 18.3
H1:ASC-REFL_A_RF45_DEMOD_LOMONCHANNEL_2 = 18.4
H1:ASC-REFL_A_RF45_DEMOD_LOMONCHANNEL_3 = -75.0432
H1:ASC-REFL_A_RF45_DEMOD_LOMONCHANNEL_4 = -74.9568
=== Rack ISC-R2 U10 (WFS REFL_B) ===
H1:ASC-REFL_B_RF9_DEMOD_LOMONCHANNEL_1 = 19.3
H1:ASC-REFL_B_RF9_DEMOD_LOMONCHANNEL_2 = 19.2
H1:ASC-REFL_B_RF9_DEMOD_LOMONCHANNEL_3 = 19.2
H1:ASC-REFL_B_RF9_DEMOD_LOMONCHANNEL_4 = 19.2
=== Rack ISC-R2 U08 (WFS REFL_B) ===
H1:ASC-REFL_B_RF45_DEMOD_LOMONCHANNEL_1 = 18.5
H1:ASC-REFL_B_RF45_DEMOD_LOMONCHANNEL_2 = 18.2
H1:ASC-REFL_B_RF45_DEMOD_LOMONCHANNEL_3 = 18.3
H1:ASC-REFL_B_RF45_DEMOD_LOMONCHANNEL_4 = 18.4

The 2 broken channels (together with the RF readbacks) are from Beckhoff chassis corner 4 terminal M4. All channels on this module read a value close to zero. Could be a cable problem between the demod chassis and the ASC demod concentrator.

I'm moving the old conlog machine to a new rack, so it (and by extension the historical data) will be unavailable for 15-20 min.  The new production conlog system will be unaffected.

Gains to decouple bottom mass (pitch and yaw) angular motion from top mass longitudinal drive at DC were implemented in L2P and L2Y components of the top mass drivealign matrix of MC2 using the dc magnitude of the top to bottom L2P (urad/Force cts) and P2P (urad/Torque cts) for length to pitch decoupling and L2Y, Y2Y for length to yaw decoupling. This should be tested.