After I restarted the corner beckhoff machine, the timing system did not come back.  I has an error on Corner Master A, Fanout 15, VCXO control voltage.

I've installed tilt decoupling on:

- ST1 BS

- ST2 ITMY

I've started working on ST2 ETMX & ITMX but haven't finished yet. I'll kkep going as soon as I have access to the platforms.

For the curious ones, you can find the DTT templates with the results of the tilt decoupling into the SVN:

/ligo/svncommon/SeiSVN/seismic/BSC-ISI/H1/<CHAMBER>/Data/Transfer_Functions/Measurements/

Stefan briefly mentioned in his alog last night that something happened with HEPI that caused them to realing etmx and TMSX

Today I tried to check the TMSX alingment using the baffle PDs, and found them 25 urad away from the saved positions  (I've saved new posoitions for both PDs and the aligned state).  For the record the positions were:

PD1 202.9 P -232 Y PD4 272 -293.8 saved

PD1 204.3 P -207 Y PD4 274 P -269 today aligned 238.15 -237.9

I've attached a screen shot of the CPS positions, after a glitch in HEPI stage 1 move by 10 urad, and stage 2 by about 15 urad in RZ.  According to Sebastian the total yaw the TMS would see will be the sum of these, so the ISI move explains the required move of TMS.

J. Kissel

Following the same procedure outlined in LHO aLOGs 9453 and 9079, I balanced the coils on the PUM stage of H1 SUS ITMX. The final balanced gains in the L2_COILOUTF bank are

H1 SUS ETMX
Channel     Balanced COILOUTF Gain
L2 UL            +0.909
L2 LL            -0.965
L2 UR            -1.035
L2 LR            +1.099

The precision to which we could balance the coils was limited by the really windy day ground motion, but we believe the obtained values are good to within +/- 0.5%.

This balancing has reduced the L3 P and Y caused by a L2 pringle excitation at 4 [Hz] by
   DOF                  Reduction Factor @ 4.0 [Hz]
    P                          > 14.6      (peak below the noise, and totally incoherent)
    Y                          > 10.1      (peak below the noise, and only ~45% coherent)
The attachment shows the result from which these values were obtained, comparing the optical lever ASD at 4 [Hz] driven from L2 at the same amplitude for both balanced and unbalanced configurations.

J. Kissel, C. Ramet, S. Biscans, B. Lantz

While grabbing data for the windy day today, I found that the temporary T240 that has installed at the X end station (see LHO aLOG 9758) was not being read out by the channels H1:ISI-GND_ETMX_{X,Y,Z}_DQ, and therefore not stored in the frames as expected. I found that the bug was in the ISI's front-end model where the channels on which the T240 were coming in were piped into the spigots for the "A" STS right off of the ADC, where it should be piped into "B." Check out D1400077 for more details and detailed redlines to both the analog wiring diagram and Simulink front-end wiring diagram. Finally, I've filled in the STS2CART matrix such that the T240 is now properly piped into the ground sensor correction path.

 

Mitchell and I got one more set (Pier 1, NW) of HEPI Actuators installed.  We ran into a problem though with the tilted tripod bar running into the Sensor Holster and locking up losing adjustablility.  I've noticed the closeness of this before but had never heard of a problem from LLO HEPI experience.  Anyway, we could not adjust the position to center the sensor without jamming/tilting the holster and locking it into position.  So we've taken the holster off and will mil it down a bit to give it some more clearance.  Definitely an issue to watch for during commissioning incase we incounter problems when adjusting Sensor Zero.  See attached sketch for idea of problem.  Who'd a thunk 30mils clearance would never be too little?

I tried running tf's on ETMY last night, but was foiled by my lack of understanding of the ETM sus overview screen (see Jeff's log # somethingorother). After SUS finished up alignment, I went down and unlocked the ISI to try again. After several hours of fruitless DTT tf's I'm giving up for now. I went down this morning and fiddled with the cables some, we tried several quad configurations (normal damping, increased pitch damping and all off), but have only managed to get worse, not better. The best guess we have right now is that maybe TMS is causing the badness (they are unplugged and can't damp at all) , but it doesn't seem a good guess because they weren't damped on the test stand (I think). More digging tomorrow, Arnaud wants the chamber for tonight.

For context, the attached DTT shows one degree of actuation and 3 associated sensors. Each curve  should kind of look like the red trace, make a peak(s, 3 seems normalish for this chamber) @ 1hz , then a valley @2.5hz, then another peak(s) @ 5hz. The extra notches at 2, 4 and 9.5 hz are "bonus", or maybe "bogus".

LVEA Laser Hazard

08:43 Justin – Working on IOT2R table
09:27 Betsy, Travis, & Jason - End-Y working on ETM-Y alignment
09:30 Jax – End-Y working on table
09:30 Andres – LVEA SUS test stand working on BOSEMs
09:30 PSL Status is good. All parameters are OK
10:30 Rick & Chris – Working in H2-PSL enclosure 
10:45 Rick – Craning items over beam tube
11:17 Karen – Finished cleaning at HAM4 and HAM5 area
11:44 Andres – Out of SUS Test Stand 
13:06 Karen – Going to End-Y
13:30 Hugh & Mitch – HEPI work at HAM4
14:50 Karen – Finished cleaning at End-Y
15:03 Patrick – Going to Mid-Y 
15:46 Patrick – Back from Mid-Y
16:00 Hugh & Mitch – Finished in LVEA

Pumps not running -> RGA connecting plumbing at atmospheric pressure -> Will pump down and bake assembly in-situ at some point in the next few days while connected to but isolated from Y1.

J. Kissel, S. Biscans

While the PRCL team is tuning their PLL parameters, and don't need the BSC chambers, I've misaligned ITMX and ITMY such that Sebastien can do tilt-decoupling without interfering with the input arm that PRCL still needs. Note, my metric for misaligned was steering he optic off the optical lever in both pitch and yaw.
           Aligned    Misaligned
ITMX P      +48.2        +208.2   
ITMX Y      -50.2        -220.2
ITMY P      +38.7        +138.7
ITMY Y     -142.3        -277.3

This morning, Travis, Jason and I knocked in the pitch alignment of the main and reaction ETMy chains (look for Jason's alog).  As usual, we had to iteratively adjust the lower stage suspended OSEMs/flags.  Note, the UL and UR L2 stage OSEM flags are slightly off-center in the side-shift direction due to differential roll between the chains (which has been there since the inception of this QUAD, including during the last 1-arm test).  They are giving good open-light values though.

After staring at the main chain L, P, Y TFs, we (Travis, Arnaud, and I) convinced ourselves that the suspension is healthy, although there is excess noise likely due to purge air which is dropping coherence in the measurements in a few places.  We've handed off to SEI such that Jim can troubleshoot a few things on the ISI for a few hours.  We anticipate reattempting the full matlab suite of SUS TFs later this evening.

It's been some time coming but Jim finally decided to give in and say goodbye to the #1 BSC-ISI for 3IFO.

The monitor point reads 13V, and the ADC reads -20000cts, even with the input terminated.
The busted channel (CH4 is used for the green y-arm transmitted power, and was temporarily used for ITMY dither alignment by hooking it up to POB18_Q.

J. Kissel, J. Bartlett

Unclear if there was any smoking gun, but H1 ISI BS, H1 ISI ITMX, and H1 ISI ITMY all tripped at 10:32a PT (1078165983). PRCL team was in LVEA near IOT2, Andres was working near Test Stand, nobody doing any heavy lifting, no earthquakes.

ISI Configs:
Chamber      Isolation Filters      Blend Filters       First Trigger
ITMX         Level 3                   TCrappy             ST1 T240
ITMY         Level 3                   TCrappy             ST1 Act
BS           Level 3                T40mHz_N0.44           ST1 Act

Yuta, Stefan, Kiwamu

This morning, we newly started using the BS M1 longitudinal actuator to make the PRMI lock more solid. This works well.

BS M1 stage feedback:

Our next target is to get the PRC length measurement done. In order to do that, we needed the PRMI locked for a sufficiently long time (more than 20 min). This morning, we found that the PRMI dropping the lock every 5-10 minutes. After some investgations, we found that the lock loss was due to the BS M2 actuator hitting the DAC range. There was a large motion in the Michelson over a time scale of  20 sec. So we decided to use the top mass of the BS to help the M2 stage actuator at the low frequencies.

The attached is the current-emperically-optmized top stage feedback. It seems helping the middle stage a lot at the low frequencies, resulting in a long PRMI stretch. As of now, it stayed locked for more than 30 minutes and is still locked. This feedback is implented in the guardian so that it automatically engages it when the PRMI becomes locked. We didn't measure the crossover frequency, though it should be around 0.1-ish Hz.

Limitter in PRM M2 stage:

We put a new feature in our lock acquisition sequence in which a limiter in PRM M2 stage limits the feedback when the interferometer is in the acquire state. It seemed that the most shaky optic was PRM during the lock acquisitoin. The limitter reduces the kick in PRM and hope this increases the chance to grab the PRMI fringe. We will see how this goes.

Schmitt trigger in guardian:

We implemented a Schmitt trigger in the LSC guardian so that now the unlocked and locked thresholds are different.

J. Kissel, J. Warner

Jim had reported in the morning install meeting that H1 SUS ETMY had tripped at ~12:30a PT last night after a few bands of transfer functions. Turns out the reaction chain (R0) had tripped alone, because its damping loops were OFF. I've ensured the loops are installed, and turned them ON.

So as to not interfere with the purple *ahem* PRCL team, I've misaligned H1 SUS ETMX.

    Aligned   Misaligned [urad]
P     7.3         200
Y    82.9         400

While Stefan reported that ETMX HEPI 'seems to have moved' in 10570, I show that it has in fact not.  The trend of the positions attached show rock steady position for the last three days.  There were two periods of HEPI trip where it of course was not in position.  These times are 4 March ~1320--1400 and 6 March 1600-1740pst.  I checked the IPS to Cartesian matrix values and they are unchanged.

Yuta and I noticed that there was a funny glitch frequently (maybe once a minute or so) in the PRX signal as well as the IMC transmitted power. It turned out that this was due the ISS keeping trying to acquire the locked loop with no success. According to a 2 days trend (see the attached), the diffraction power dropped quite rapidly yesterday and eventually plunged into a so small value that the ISS can not lock itself any more. Because of that, the ISS had been down from 22 pm local yesterday.
I increased the offset in the error signal (H1:PSL-ISS_REFSIGNAL) from -1.85 to -1.75. This brought the diffraction power back to the nominal of 10%. Now it seems running fine without a difficulties in locking it.