Attached are the WhiteNoise transfer function measurements taken on 07/30/2012 on the HSTS metal build slated for becoming "PR2" in-chamber.  Coherence is excellent for all DoFs and resonances clearly visible.  A comparison of this data with data from the staging building build and the model will be posted.

From 17:30h to 18:36h (local time) the Cavity has been locking nice and steady, until it suddenly nose dived. Not sure why, the green power monitor increased maybe making the locking loop unstable (to much gain? haven't measured the UGF after the SHG temp mods).

I was trying to measure the TF from HEPI to the cavity error signal and the CPS. After about 30min I realised that there is no signal comming from the RFM into HEPI! HEPI looks at the same RFM locaiton as the ETM (H2:ISCEY-SUSETMY_LONG). I check in both models (h2susetmy and h2 hpietmy) which seem to be ok. I think Dave did some cleaning up on the weekend, will ask him tomorrow.

Attached plot shows a reference from last week, and a spectrum during the hour lock.

The 'ISI Low Blend (ITM+ETM)' is with a cross over frequency of 250 mHz on both stages (ITM/ETM). Currently the ISI runs with blend frequencies at 750 mHz for both stages, except in X and  Y (cavity axis) as indicated in the legend. The peaking at the 2.75 Hz is less, although an increase at the higer frequencies.

Filiberto, Richard, Corey, Hugh, Hugo,

Today's effort brought us to the point where we are able to run transfer functions:

• Un-tripped the coil driver chassis BIO WatchDog. See aLog #3648
• Installed input filters
• Installed output filters
• tested actuators -> Detected a bad routing of the signal:
  • Checked the In-Vacuum cabling - OK
  • Checked the in-field cabling - corrected mistakes caused by discrepancies in the electrical drawing D1101576
  • Checked the signal outputted by the coildrivers. The coildriver #1 (Corner 1 and Corner 2) routed the signals received from the DAC to the wrong actuators. It is and old coildriver that was inserted in the rack by mistake (S/N S1103567). It is also malfunctioning and was set aside for repair.
• Coildriver #1 was replaced with a new model of CoilDriver (S/N S1103321). Coildriver #2 was already the newest model. Testing confirmed that it works properly.
• Re-tested actuators => H2-Actuator is connected the other way around in-vacuum (minus sign corrected with a -1 gain on the actuation for the overnight TFs)
• Tested the range of motion of the ISI, it is within spec. 
• Ran a quick transfer functions (1h) around the resonances of the ISI.
  • No major case of rubbing detected
  • Transfer functions match well with reference transfer functions in that frequency range (0.5Hz-5Hz)
• Added HAM3-ISI MEDM screen to the Video6 screen of the control room so one can know when a measurement is running (see yellow blinking sign on the bottom of the screen).

Transfer Functions are running overnight. They should be done by 6am.

Note: There is a mailing list to receive the alerts regarding these transfer functions. Please let me know if you would like your email address to be added to it.

This afternoon at about 5.15pm the alarm handler went off for this channel: H0:FMC-MY_CY_H20_SUP_DEGF

I'm not sure what it refers to, but I plotted the trend for the past 2 days and it doesn't seem to be doing anything particularly unusual.

I aknowledged the alarm.

Bubba and crew craning at End-Y.  Done by 9:30.
Maggie to End-Y
Corey at HAM3 for SEI cabling

Alex and others to End-Y to power a microphone

Eric A. - installing HEPI valve plates

12:45 - Hanford call testing sirens

Craning and work with cabling inside HAM3 for Seismic

Common mode board A at H2 EY (S/N S1102638)
(Jax S., Daniel S.)

We changed the common generic filter to a double pole 100kHz/Q=0.85. This is to replace the Pomona box that was used to suppress the PZT resonance around 250kHz-300kHz. 

R129 -> 2.67K
R130 -> 1.30K
R131 -> 0
R132 -> 0
C207 -> 1.5n
C206 -> 470p

This allowed us to push the ugf to just above 30kHz with a phase margin of 45 degrees. We backed off with the gain set to -6dB in the input section which leaves us with a ugf around 28kHz and a phase margin of close to 50 degrees.

Common mode board B at H2 EY (S/N S1102637)

We also changed the fast monitor into the Beckhoff on the cavity locking servo to be unity gain rather than 10.

R271 -> 0
R272 -> NL

As I mentioned on Friday, I noticed a coherent shift of the HEPI platform on HAM3 as I was locking it up in preparation for ISI measurements.  Hugo gave me a window this morning so I unlocked the HEPI again and very thoroughly looked for interferences that might be pushing it out of our aligned location.  I could find no non-suspended elements touching suspended portions aside from a few of the temporarily run in-air cables.  I can't imagine that these contacts could pull the system around.
Once it was all released I pushed on the crossbeams to 'see' knocking.  I could not detect anything that looked like something running into something else but I did notice that the vertical moved fairly easily whereas horizontal motion was very stiff.  I'm trying to understand why this would be but nothing is so far revealed.  Thoughts?

For the record, based on the dial indicators, I see a CCW rotation of about 250urad caused by a shift to the east of the south side of about 0.5mm.

Issue with watchdog tripped - Richard, Filiberto, Hugo
Corrected, can now actuate

We managed un-tripping the coil driver chassis bio watchdog of HAM3 by:

• Adjusting connections between the Coil Drivers and the BIO Iterface Chassis (needs confirmation)
• Setting the BIO to the right state in ISI_CUST_CHAMBER_BIO.adl

In Vacuum cabling - Corey, Hugo
CPS H3 and CPS V3 were swapped - corrected 

I took spectra on our sensors this morning and noticed H3 and V3 were swapped. Corey went looking at it and located it on the in-vaccum side of the feedthrough.

Using the PT-410B vacuum gauge, we looked at the pressure in End-Y volume since its pumpdown began in early June 2012 (see attached plot). The first ~10 days is before the gate-valve that opens to the cryo pump was opened. Opening to the cryo pump reduced the pressure by a factor of 10. The start time for the plot (i.e., the offset that we subtracted from the time stamp) was adjusted (at the 0.1 day level) by hand so that the pre-GV opening segment was a striaight line in the log-log plot.

The two black lines are by-eye fits to the pumpdown curves. The slope of the first segment is 1/t^{0.68}; since the GV opening, the pumpdown is a little faster, at 1/t^{0.88}.

(Matt E, Peter F)

As part of gearing up for aLIGO CW and Stochastic analysis detector characterization,
a number of us are developing and starting to use new or enhanced spectral line finding
tools. We plan to apply these various tools to this summer's OAT data in the hope of
1) making the tools better via exposure to real data; 2) identifying spectral lines early
on that can be mitigated; and 3) cataloging lines that we have to live with in aLIGO.

A wiki clearinghouse for OAT spectral line studies can be found here. For now it has
mostly documentation on tools and channel selections, but over time it will be populated
with study results.

One important tool is an enhanced version of the familiar Fscan program. Greg Mendell
has started creating daily Fscan plots for locked-arm data (defined by the mean value of
H2:ISC-ALS_EY_REFL_PWR_MON_OUT16 over 1 minute lying in the range 4300-8000 -- see wiki
above for explanation). The Fscans generated so far cover only the days of July 16 and 20,
chosen because each had more than five hours of locked-arm data.

I have used the half-hour SFTs generated during the Fscanning to look at average spectra
for the calibrated OAT feedback channel H2:SUS-ETMY_M0_LOCK_L_IN1_DQ for July 16 (5 hours)
and July 20 (9 hours) with 0.56 mHz binning. Two different averages were computed, one
being a simple arithmetic average, the other a noise weighted average that is almost, but
not quite the same as a harmonic mean. (The same method was used to compute unweighted
and weighted averages for h(t) for all of S5 and S6, as discussed in more detail here.)
Generally speaking, one expects the weighted average to be lower than the unweighted
average and to have a smaller variance. Large differences between unweighted and
weighted averages indicate non-stationary bands.

The figures below show the results:

Full spectrum (0-1000 Hz) for July 16 (unweighted and weighted averages)
Full spectrum (0-1000 Hz) for July 20 (unweighted and weighted averages)
Full spectrum (0-1000 Hz) for July 16 and 20 together (weighted only)
Zoomed spectrum (0-2 Hz) for July 16 and 20 together (weighted only)
Zoomed spectrum (2-10 Hz) for July 16 and 20 together (weighted only)
Zoomed spectrum (10-100 Hz) for July 16 and 20 together (weighted only)
Zoomed spectrum (100-200 Hz) for July 16 and 20 together (weighted only)
Zoomed spectrum (200-800 Hz) for July 16 and 20 together (weighted only)

Some quick observations:

The full spectrum is "rich" with structure (how much of it is relevant to
eventual aLIGO operations is not clear, however)
The July 20 noise is below that of July 16 over most of the full band (good to see!)
Here is a small sampling of line artifacts above 10 Hz (band of direct interest to the CW/Stochastic groups):

120 Hz is easily seen, but 60 Hz is much weaker in July 16 data (stronger in July 20 data -- was there a 60-Hz notch on this channel on July 16?) There is a peak near 180 Hz (179.9 Hz), but I don't think it's a 60-Hz harmonic. 
There is a persistent comb at 2.74 Hz seen out to at least the 25th harmonic in the July 16 data, but quite mitigated in the July 20 data
There is a very strong line at 29.375 Hz with rapidly weakening harmonics visible at 58.75 Hz, 88.125 Hz and 117.5 Hz 
Other strong lines below 200 Hz include 77.30 Hz (and harmonic at 154.60 Hz), 78.15 Hz, 89.54 Hz (and harmonic at 179.08 Hz), 90.40 Hz (and harmonic at 180.80 Hz), and 105.92 Hz
 


Chores ahead of us include dealing with some auxiliary channel issues in Fscans, getting Virgo's NOEMI line-finding tool to work with only locked-arm data, resurrecting automated coherence measurements between the OAT feedback channel and ~100 auxiliary channels -- and digesting all of the results once they appear. 

Future reports will be posted both here in the alog and on the wiki page. 

Patrick changed the Beckhoff channel name for the ref cav trans to H2:PSL-FSS_TPD_DC_OUTPUT and restarted the Beckhoff EPICS IOC on h2ecatey. I then added this channel to the H2EDCU_ECATEY.ini slow chans file and restarted the H2 DAQ Friday afternoon.  This channel can now be trended from H2 DAQ.

This DAQ restart also picked up new fast INI files for H2SUSETMY, H2SUSITMY, H2ISCEY following work by Jeff K and Bram.