Alberto, Bram

The arm has been locked since 20:00 local time.

Due to the RFM not working iwrote a littel Perl script which reads the  H2:ISC-ALS_EY_ETM_LONG_OUTPUT and writes it in H2:HPI-ETMY_ISCPF_LONG_OFFSET to get the communication between the ISC modle and the ETMY HEPI model going. It runs in a terminal window.

We ran a sine response function at 10 mHz, which pushed ETMY HEPI at _ISO_Y_EXC and recorded the _BLEND_IPS_Y_IN1 and in the ISC model the _ETM_LONG_OUT. The ETM_LONG_OUT ratio was 0.44 at -180 degrees. We wanted the UGF at 1 mHz, so we set it to +0.2 (~6dB less). The filter is an intergrator (pole at 0) in _EY_ARM_LONG FM1 and there is a cutoff with two complex poles at 100 mHz in EY_ETM_LONG in FM1. There is a 1x1 matrix between the ARM_LONG and ETM_LONG. In the EY_ARM_LONG the limiter is engaged at 200k.

We locked tha cavity and enganged the offloading to HEPI .... it ramped quite nicely as seen in the first striptool plot. In between I changed the gain down to 0.15 as I thought I saw the beat frequency breathing with a period of ~5min (~3 mHz), but returned it to 0.2 after ~30 min.

In the attached spectrum the peak at 2.75 Hz is down quite a bit, but then there is an increase in noise at the higher frequencies. At other moment, the 2.75 Hz peak is as previous but the higerh frequencies are much lower.

Due to the power fluctuations, I adjusted the _REFL_PWR_MON offset to keep th eoutput below 9000 (although it did shoot above that, but the cavity was still locked!).

We will leave the cavity locked over night ..

What a fun afternoon was had by Filiberto, Hugo and I.  Lot's of little problems confounding troubleshooting of main problem.  To start with the Binary I/O on Ham3 Gain and Filter stages did not appear to be functioning.  The MEDM button was pressed with no effect on the hardware.  Started trouble shooting and the problem was confounded by cables with missing pins. Pin 5 missing of some of the 9 pin cables that were substituted into the system because not all the cables for the Ham arrived. This lead us down the wrong path for a while.  When this was finally discovered we then had problems because the model uses the first binary I/O board and the DWGs called out the second.  That or my understanding of the backplane is wrong.  Of course in the earlier rounds of troubleshooting we used every combination of cable from the BIO boards thinking this was the problem but with the ground pin missing we could not tell. So we also swapped the two BIO cards in the chassis just for fun.  In the end we have installed 6 9 pin straight thru cables and everything seems to be working.  Rather frustrated it took so long.

This pump finally shorted internally (typically expires @80,000 hours, lasted 105,000 hours)

Robert and I investigated noise sources contributing to the optical lever spectra for ETMY in this entry using recently installed PEM accelerometers. We were able to identify and remove three noise sources:

29.5 Hz
Annulus pump that was left on. The pump has since been turned off and will be removed from EY today.

90-91 Hz
Power supply for optical lever laser on the receiver pier. We moved this to the floor by the receiver pier and seismically isolated it from the floor using inflated clean room gloves.

56.5 Hz
Power supplies on floor near receiver pier. We placed these on a seismically isolated platform using springs.

The above changes removed the peaks in the optical lever spectra at 29.5 Hz and 90-91 Hz, and reduced the peak at 56.5 Hz by a factor of 2. We believe there are other sources contributing to the 56.5 Hz peak. Attached are the ETMY optical lever spectra before and after the above changes were made (including spectra for a recently installed PEM accelerometer mounted on the receiver pier), and pictures of the three noise sources.

The 29.5 Hz signal was also found in the OAT length error signal before the pump was shut down, as seen in an attached plot.

DTT template used is located here:
/ligo/home/robert.schofield/12sAug/OAToplev.xml

Corey, Mitchell, Hugh

We set the Optical Table in WHAM2 at -252.9 (E1000403) + 12.5 (T1100187-to correct for X-arm slope[local gravity plane vs LIGO Global Frame])= -240.4mm below the center of BSC2 where the local level and LIGO Global cross zero.  The Optical Table is level to +-0.2mm.

The HEPI remains floating and is ready for Initial Alignment horizontal adjustment.

Attached are plots of dust counts > .5 microns in particles per cubic foot. The dust monitor in the H2 PSL laser room (H0:PEM-LVEA_DST13) has a calibration error and is not included.

Sprague on site
Unifirst on site

8:45 Eric to work on HAM2
8:46 Cheryl to remove H1 ETMX
8:54 Volker to work in H1 PSL enclosure
8:55 - 9:35 Kyle to remove pump from BSC6 annulus
8:59 - 10:05 Corey to switch cable in HAM3
9:01 - 11:33 Filiberto to work near HAM2 on seismic cable
9:22 mopping, vacuuming in LVEA
~11:30 - 1:00? Robert to set up coils near BSC8
9:27 Michael R. to work in H1 PSL enclosure
9:42 - 9:55 Bubba, Hugh to remove tote from LVEA by hand
10:38 Robert, Maggie to work in optics lab
10:38 Corey to look for rigging in LVEA
11:28 Eric to work near BSC1 and BSC2
1:15 Richard to work in plenum?
1:30 - 3:50? Corey, Hugh, Mitchel surveying HAM2 ISI table
1:35 Jax, Elli to work at end Y
2:14 Apollo to move parts for optics extraction into mid Y

Jax, Bram, Elli.  We repeated the measurement we made last week on 26 July of measuring how the 532nm laser power output changes as you vary the doubler crystal temperature.  Measurements were taken over a greater range than last time.  The attached graph shows today's measurements (blue) and well as those taken last week (red).

The laser diode current was set to 1.725A and the 1064 crystal temperature was 42.14 degrees C.  As the graph shows, the maximum power output occurs at about 34.36 degrees C, althought the actual power output at this temperature varies between 40-45mW.

We also took a couple of measurements about the REFL_PWR_MON, GREEN_PWR_MON and IR_PWR_MON photodiodes.  First we measured the signal in counts of the output of these channels.  Then we covered each diode so no laser light hit it and measured the output signal again.  Then we measured the power incident on each diode in mW using the power detector.  The readings are as follows:

Cheryl and I went into BSC9 to look at the particulate contamination in the viewports and at the drop-off by the gate valve. (Cheryl said that the contamination was the worst she has ever seen: my take is that this stuff looks very much like what we saw during the initial survey down the tube at BSC8.)We took some pix and a sample for analysis. Then, we removed OSEMs and preserved them clean. I came out: Scot and Ed went into the chamber with Cheryl. Mark D.and Bubba were also outside. The Lazy Susan, Slide Table and Lift Table were inserted. The SUS was removed, wrapped and set aside so that the optic can be put in a cake tin. The optics table was cleared and the telescope preserved clean. The VEA was cleared of SUS de-install tooling to make way for SEI stack extract tomorrow. 

I have been working on assembling 10 grounding plugs for the TEST In connection on the Coil Driver boards, building on work described in https://dcc.ligo.org/cgi-bin/private/DocDB/ShowDocument?.submit=Number&docid=l1200193&version=  These grounding plugs make use of 100 Ohm resistors across pairs of pins and a 0.022 uF capacitor connected between the remaining pin and the DB9 connector metal (see page 16 of the document above for the schematic).  I will next measure the coil driver noise with these ground plugs in place across the TEST Input path.

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.

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.