The aLOG was down for a short while today. This happened after the UPS power cycled in order to clear some communication glitches. The power did not properly switch over on the systems from UPS to system power.

I will likely take the aLOG down tomorrow during the maintenance window to try and reproduce and diagnose this problem.

This also affected the SVN server and the bugzilla a server.

I made some edits to the IMC guardian over the weekend.  I added some error checking to IFO_IMC. 

There is an error check function, in acquire if the IMC is not locked the errors are checked, if any of them are problems a message is written to the log, and the guardian enters the error state.  Jamie is going to find a wway to make these messages appear in a more prominent way, but for now we shoud look in the log whenever the guardian is in the Error state. 

This seemed to be working on saturday afternoon.  Occasionally (although not every time) the guardian fails with an error message:

User warning ca.get('H1:SUS-MC2_M3_WDMON_STATE') timed out after 1.00 seconds

File: ligo/apps/linux-x86_64/cdsutils/lib/python2.7/site-packages/ezca.py, line 194, read

raise EzcaError: could not get value from channel H1:SUS-MC2_M3_WDMON_STATE

Less than 3 hours after getting it damped.  Seems like too long a time to be an instability but who knows.  Attached is 30 minutes of the T240 before tripping.  Seems like an abrupt railing spike, not a building and continuing EQ surface wave.  Anyway there isn't a timely EQ for this one.  The SUS didn't trip and neither did HEPI; got to figure out the WD scheme.  Seems like this ISI has never survived more than a few hours....  I'll put it in lvl1 and see how it does this morning.

So ETMx ISI is in lvl1 isolation at ~0800pst.

Wasn't watching the process as I've done this a few times but the SUS tripped for the first time triggering the SEI ISI and HEPI.  Painful cause this has the large pitch offset to tilt the TMS down to the corner.  I've got it back damped (SUS w/ Kiwamu's help) and the HEPI tilted and the ISI in lvl2.

Running Transfer Functions on ITMx and ETMx – Hugh
Optical Lever electronics work  at End x – Thomas
Demo board repair on ISC PSL Racks – Aaron
Cryo baffle assembly  End Y – Mitchell/Gerardo

I activated unit-1, unit-2 is now "resting".

Gerardo, Mitchell,

Yesterday Gerardo removed parts and hardware from the Cryo baffle assembly and moved them to the LVEA for the ITM-Y assembly. Today he and I installed the Eddy current dampers thus completing all work (for the Cryo baffle) at the end station. 

The HEPI XFs are done for the moment so these have been put back into running state

ITMX HEPI is on but doing nothing.  ITMX ISI is in DAMPING only state.

ETMX HEPI is on and tilting -12000 Ry.  ETMX ISI is damping and isolating at lvl1.  I may push this up to lvl2 to see how it survives.

Overnight TF's on ITMX HEPI were mostly succesful, but it looks like we have an issue with instrument pods, or associated rack chassis in one of the corners. All of the IPS's and L4C's in corner 3 on this chamber look bad. Power spectra also don't look great.

See the attached files for the XFR plots.  All the channels look similar with good coherence.  These are local to local with IPS and L4C responses.

Sheila, Daniel

Today we increased the power from the laser onto the fiber locking BBPD, from 1mW to 9mW.  We first tried 25mW, but we might have been overdriving the phase frequency discriminator with that much power, the pll was able to lock but with a lot of excess noise.  With 9mW we get a large enough beat note that the frequency comparator is working well, but we do not see excess noise on the beatnote on the RF analyzer.  (will double check RF level in the morning)  This means that the autolocker is now working for the PLL.  Daniel also changed the attenuators for the VCO input to the frequency comparator, I think to 20dB ( I also need to double check this in the morning). 

We also looked into why the photodiode gains were not changing.  The power supply in the beckhoff unit for that chassis was not connected to the modules, so none of the binary outputs were working.  After we connected them we adjusted the calibration of the fiber trans, IR laser monitor, and fiber polarization monitor PDs, which we originally did taking into account the non working gain settings.  

We also found a on Track QPD to monitor the beam position on the green refl diode.  I replaced the HR steering mirror in the path the the PD with a 80% reflector, to make a pick of for the QPD.  We had completely lost the return beam, presumably because of seismic commissioning, so we didn't align this yet.  

[Stefan, Kiwamu]

We adjusted the phase difference (e.g. LSC-REFL_A_RF9_PHASE_D) of all the REFL and POP demodulators except for a WFS channel which showed suspiciously small signals.

Observations on the I/Q relations:

We discovered that the amplitude imbalance between any pair of I and Q were good and were typically less than 0.5%.  Also, the extra imbalance that can be introduced by changing the whitening settings are almost comparable to 0.5% and we concluded that it was pointless to correct the amplitude imbalance at this point unless the whitening settings are fixed. Therefore we didn't attempt to correct them this time. On the other hand, the phase difference was not as sensitive as the amplitude imbalance to the whitening settings. They were found to be typically off by a couple of degrees from 90 in the first place, while changing the whitening settings didn't rorate them more than 1 degree. This is the background story of why we ended up adjusting only the phase differences.

One demod board doesn't look healthy:

In the process of the adjustment, we found that channel 4 of the WFS REFL_B_RF9 demod board (SN:S1000994) displayed too small signals in both I and Q by a factor of 2-ish in their amplitudes compared with the rest of three channels. We must pull this board out of the rack and take a close look in the EE shop.

Adjustment of the phase difference:

We used the same technique as Anamaria did at LLO (see LLO 6829). The RF frequency was set apart by 40-50 Hz from the LO frequency in each demodulator by using an IFR RF source. The RF level was at -40 dBm for the LSC demods and -41 dBm for the WFS demods. None of the whitening stages were engaged. The whitening gains were simply set to be their maximum (i.e. 45 dB) during the measurement. The belows are the results:

* * * in-vac 1f

H1:LSC-POP_A_RF9_PHASE_D       87.30
H1:LSC-POP_A_RF45_PHASE_D      92.93
H1:LSC-REFL_A_RF9_PHASE_D      88.63
H1:LSC-REFL_A_RF45_PHASE_D     92.98

* * * in-air 1f

H1:LSC-POPAIR_A_RF9_PHASE_D    87.78
H1:LSC-POPAIR_A_RF45_PHASE_D   92.95
H1:LSC-REFLAIR_A_RF9_PHASE_D   88.27
H1:LSC-REFLAIR_A_RF45_PHASE_D  92.98

* * * 2f and 3f

H1:LSC-POPAIR_B_RF18_PHASE_D   89.17
H1:LSC-POPAIR_B_RF90_PHASE_D   91.05
H1:LSC-REFLAIR_B_RF27_PHASE_D  91.39
H1:LSC-REFLAIR_B_RF135_PHASE_D 84.49
 

* * * WFS REFL 9

H1:ASC-REFL_A_RF9_SEG1_PHASE_D 88.28
H1:ASC-REFL_A_RF9_SEG2_PHASE_D 88.34
H1:ASC-REFL_A_RF9_SEG3_PHASE_D 88.55
H1:ASC-REFL_A_RF9_SEG4_PHASE_D 88.55
H1:ASC-REFL_B_RF9_SEG1_PHASE_D 89.17
H1:ASC-REFL_B_RF9_SEG2_PHASE_D 88.32
H1:ASC-REFL_B_RF9_SEG3_PHASE_D 88.64
H1:ASC-REFL_B_RF9_SEG4_PHASE_D 0
 

* * * WFS REFL 45

H1:ASC-REFL_A_RF45_SEG1_PHASE_D 91.96
H1:ASC-REFL_A_RF45_SEG2_PHASE_D 93.15
H1:ASC-REFL_A_RF45_SEG3_PHASE_D 92.37
H1:ASC-REFL_A_RF45_SEG4_PHASE_D 93.18
H1:ASC-REFL_B_RF45_SEG1_PHASE_D 92.80
H1:ASC-REFL_B_RF45_SEG2_PHASE_D 91.65
H1:ASC-REFL_B_RF45_SEG3_PHASE_D 92.88
H1:ASC-REFL_B_RF45_SEG4_PHASE_D 93.00
 

Reduced the drive on the transfer function for HEPI in the 500 to 1000 hz band.  We've experienced a trip for the L4C everytime the TFs would get to the V4 drive.  I can't find an unusual drive (DC level) here relative to the other drives nor an obvious L4C response difference--the L4Cs all look the same to back ground input and the Actuators all displace the IPSs about the same.  The corner 4 L4Cs both H & V do seem to respond more greatly to all the drives than the other corners do; but the others do have varying levels of response to the drive on the different corners.  The response to V4 drive at V4 is just the strongest.  I reduced the drive to 0.5 (from standard 1.0) and it made it through.  I increased it to 0.75 and it tripped but only on the second iteration.  So I'm running the TFs now with this mod (gain=0.5) from previous chamber commissions.  Maybe there is a loose bolt somewhere?

Attached is a plot showing the L4C responses as the TFs go through the drives.  The Drives run H1 H2 H3 H4 V1 V2 V3 V4 although I've got them jumbled in the plot.  But you can use this to see how every corner is responding to the 8 local drives.  The WD trips as soon as V4 starts so you can work back through the plots to get your bearings of where things start.  It is interesting when you realise the response on a corner/HorV isn't necessarily the largest when that corner/HorV is driving.  For instance, V2 responds more greatly to the H2 drive than it does to the V2 drive.

LVEA Laser Hazard

08:57 Apollo at End-X setting Optical Lever piers 
09:10 Praxair delivery to CP-3
10:09 Thomas at End-X working on Optical Levers
13:18 Kyle working on vacuum pumps at End-X
15:02 Gerardo moving baffle parts into the LVEA

The ISI is damped only.  There are two matlab sessions working this running on opsws0.  Thanks for letting this run (overnight likely.)

Andres R. & Jeff B.

   We suspended H1-SR2 with the metal dummy mass installed. Checked several of the critical measurements to make sure nothing was disturbed during the transport of the suspension to the LVEA. All measurements are within specifications. 

   We centered the BOSEMs and took a set of transfer functions for phase 1b testing.
 
   The TF plots are attached below. There is some noise below 1Hz. However, as we are going to swap out the bottom wires, the M3 mass, and rework the suspension anyway, spending much time tracking down and fixing this noise is not a high priority.