In response to Keita's alog (here) I changed the whitening gain and number of active filters on the ITMx, ITMy, and ETMx optical levers.  They are now set as outlined in the 2nd table in Keita's alog.  I also enabled the corresponding de-whitening filters in the oplev filter medm screens (ITMy and ETMx only, as these were the only ones that had additional whitening filters enabled) and accepted the changes in SDF.

I took spectra of each segement of the QPD for each TM oplev, both before and after the de-whitening filters (channels labeled IN1 are before de-whitening, channels labeled OUT are after de-whitening) as well as spectra of the pitch and yaw signals of each oplev..  To my knowledge, ETMx and ETMy look as they are supposed to.  On the other had, the ITMx and ITMy QPD spectra do not look right to me.  When I took the spectra there were ongoing investigations into ITMx ISI coil driver issues and ITM charge measurements (ie, the optics were moving); also, the oplev lasers for both ITMx and ITMy oplevs are unstabilized lasers, sitting on the LVEA floor.  All of these could be causing issues with the measurements; they should be re-taken once things have quieted down and see if there are differences.  If there are no differences, I fear we may have made things worse for the ITMs.  There also appears to be a comb in all of the ITMy spectra.  I think this is caused by the laser glitching; as soon as I have a stabilized laser ready for install this laser is getting replaced.

This completes WP #6020.

Had bagged entire RGA assembly previously -> Removed 1.5" O-ring valve (redundant valve in series with 1.5" UHV valve) and installed turbo in its place.  Backed turbo with leak detector.  Opened 1.5" UHV valve to combine detector with RGA volume.  Helium line penetrated bag at top while O2 sensor (with internal pump) penetrated bag at bottom.  No flow meter on helium but set to "significant" flow rate.  O2% fell from 20% to 1.6% over 10 minutes.  No leaks detected with helium baseline holding @ 1.2 x 10-9 torr*l/sec or so throughout the helium application -> Once convinced that no leaks were present, I closed the 1.5" UHV valve and "cracked" the isolation valve of the external calibrated helium leak and observed the expected response; thus demonstrating that the mass spec. was sampling the test port during testing.  

Installed 5 of 6 heat tapes on RGA assembly in preparation of baking it out at the next available opportunity.

Note to self: The isolation valves for the Nitrogen and Krypton calibration gases were closed during this testing so the two "factory" double-sided mini-conflat joints did not get tested.  Also, I noticed after shutting down and decoupling the leak detector etc. that the factory 2.75" CFF joint between the RGA analyzer and its protective nipple showed a crescent shaped gap.  All of the joints tested in this excercise (12 or 13?) where ones that I bolted and are "metal-to-metal" and won't change with with baking.  This sole gappy joint could leak following a thermo cycle so I will "cinch" it up and leak check it along with the two double sided joints that I missed before baking.

J. Kissel

We're still struggling to get past the Parametric Instability Phoenix (e.g. LHO aLOG 28600), so we haven't had much IFO time / patience to debug ESD bias sign flipping. As such, the charge, effective bias voltage, and actuation strength continue to change slowly. Again (see last week's report in LHO aLOG 28523), ETMX is charging about twice as fast as it has between the prior two flips, so its accumulated charge will begin to get excessive sooner than ETMY.

I'll keep pushing for a debug of the bias flipping, but we've got higher priorities with the IFO stability at the moment, and the change from charge is not out of control or ridiculous. Yet. 

I swapped the oplev laser for the ETMy optical lever in order to address the problem noted by Sheila here.  The laser will need 4-6 hours to come to thermal equillibrium.

The SN of the new laser is 130-1.  This completes WP #6013.

J. Kissel, J. Betzwieser, B. Storr
WP #6023

Joe and Bria have discovered a small bug in the future monitoring of the IFO response parameter time-dependence regarding the use of the sub-function atan2 (see LLO aLOG 27214). As such I've svn up'd the affected library part, 
/opt/rtcds/userapps/release/cal/common/models/CAL_LINE_MONITOR_MASTER.mdl
and recompiled, restarted, and restored the model to the OBSERVE SDF file (which I'd reconciled before restarting).

The flow sensor in the crystal chiller was replaced.  The water filters in the chiller room were also
replaced as per work permit ...
6008

    Power cycled both the diode and crystal chillers.  Rebooted the Beckhoff computer.  Right away an
increase in the flow rate of the crystal chiller was observed.  The error message also disappeared.
A plot of the before/after flow rates is attached.

   The exception delay in the crystal chiller was set back to 000 s.



JeffB/Jason/Peter

Richard told me the crystal chiller was alarming this morning, in addition to the message about the flow
sensor error.  Nothing a top up of its water level didn't solve.  Added about 100 millilitres.

The LVEA has transitioned to  LASER SAFE. 

    On the walk around, the left hand side door of TCS-X was found closed but unlocked.  Please
check your enclosure doors when your table work is completed, thank you.

TITLE: 07/26 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: Travis
SHIFT SUMMARY:  Locking at 50 W for commissioning work.  Evan and Koji replaced ASAIR PD.  No issues.
LOG:
 

23:39 Nutsinee and Betsy to LVEA HWS table

0:07 Nutsinee and Betsy out

Evan and Koji replacing ASAIR PD after lockloss

6:44 EQ/Wind took us down, nobody except Terra is here, calling it a night

Just a quick note becuase this investigation isn't quite complete yet, but I can improve the recycling gain by moving the SOFT offsets in pitch after moving the PRC1 pitch offset.  I have not yet tried adding yaw offsets to this.  With pitch only, I can get up to 30 at 50W (previous record was 28 at 50W). 

What we'd like to do after finding a semi-good spot is to move the beam spot on some of the PRC mirrors (see Stefan's recent alogs for scripts that do this), which will hopefully let us move the spot on POPA back closer to the center.  I wants to be at least 0.65, which is getting uncomfortably close to the edge.

Koji, Evan

We removed the unmodified BBPD S1200242 from ISCT6, and replaced it with S1200236, which has the modifications described in G1500595.

(As Jenne requested) To avoid the confusion, the control room OBSERVE banner on Ops Overview will no longer show if the intent bit is not set. The banner will show only when both "Ops Observatory Mode (Observing)" and "Undisturbed" buttons are engaged.

Betsy, Nutsinee

LLO recently found their HWS mirrors to be contaminated (LLOalog27041). So we went to the table to take a look at our mirrors and took some pictures.

The mirrors are dusty overall and periscope mirrors show sign of coating degradation (I assume that the watermark-looking patterns are coating defects) Betsy later explained to me those marks are leftover marks from First Contact. See below:

HWSX bottom periscope mirror

HWSX top periscope mittor (sorry I wasn't able to get a good shot)

HWSX STEER M7 and STEER M8

HWSX STEER M6 with flash light shined through the back.

HWSY bottom periscope mirror

HWSY top periscope mirror

HWSY periscope mirror with flash light shined through the back

HWSX return beam (without Hartmann plate)

HWSY return beam

HWSX has been giving us data that makes sense. HWSY data however makes no sense. I forgot to stop the code when I took the Hartmann plate out and in and somehow that caused the scripts to think that there were only few hundred peak counts when everything was closed out. I re-initialized the reference images for both HWSX and HWSY. Every necessary optics were aligned and CO2 heating power was set for 2 W PSL input.

Following the same idea as elog 28442, here is a script for moving the beam spot position on PRM (prmspotmove.py).

It monitors IM3 slides, and moves IM4, PRM and PR2 sliders in such a way the the beam spot positions on PR2 and PR3 don't change.

The script was tuned in INPUT_ALIGN (for IM4 and PR2 matrix elements) and PRM_ALIGN (for PRM matrix elements).

Matrix  elements (in rad /rad IM3)

pitIM3toPR2=+0.0022;
yawIM3toPR2=+0.0055;
pitIM3toIM4=-1.3;
yawIM3toIM4=+0.92;
pitIM3toPRM=-0.009;
yawIM3toPRM=+0.031;
 

Also attached is the python script used for finding the matrix element, getMx.py.

Decreased CP3 LLCV from 24 to 21% open

I have been taking spectra from the SR785 (WP6005) whenever I get a chance over the last week to see if there is any evidence of three mode interactions in the 60kHz to 70kHz region that we will not be sensitive to with the aliased OMC DCPD HF channels that we normally analyze.
There is a consistent peak at 62935Hz, this peak is present with no optical power in the arm cavities.
There are several other more transient peaks, one of the times several had large amplitudes is shown in the first figure.
The largest peak is at 63776Hz  The maximum amplitude seen was 5E-6  This is about the same as the 18040Hz mode when it is 2 orders of magnitude above thermal noise and 2 orders of magnitude under unlocking the cavity.
The second largest is at 70160Hz and the third largest at 62336.

There is no evidence of peaks in DARM at this time at the expected aliased frequencies 1760Hz,  3200Hz or 4624Hz and the peaks that appear in the HF channels that do not appear in the normal DCPD channels do not coincide in frequency, see the second image.

[Matt, Carl]

The phase lock loop is now installed as an optional tool in the PI armory. I have used the settings and method Matt demonstrated to me on the test stand to lock onto OMC PI signals in the last 50W lock. I tried locking onto QPD signals but was unable to at quiescent amplitudes. The phase locked loop in the locked state is shown in the first image. It is tracking a 15521Hz ITMX mode (sorry for the poor labeling in the figure, there's still a few bugs in medm screens).

The settings used were:
Filter I - 100Hz LP Gain 1
Filter Q - 100Hz LP Gain 1
Freq Filter 1 - gain 1
Freq Filter 2 – gain 0.02, 20mHz integrator + low pass see below
FC Count - 10mHz low pass (this was not low enough as the frequency estimate was still fluctuating by 20Hz
Ampl Filt er - 1Hz low pass gain 1
Lock Filter - 1Hz low pass gain 1

Lock was acquired by setting a set frequency close to the mode frequency observed in a spectrum of the OMC HF channels. The loop was engaged with a 100Hz low-pass in Freq Filter 2 then put in a narrow band mode by engaging a 1Hz low-pass in Freq Filter 2, the loop lost lock when I tried to further reduce its bandwidth by either reducing the gain of decreasing the frequency of the low-pass. The figure is in the high bandwidth mode.  The PLL and iwave can be accessed from the mode block for any mode and a matrix is used to select a control signal, see the second image.

Executive summary: 

* Good news - as expected, the 16-Hz comb due to the OMC length dither is gone (at least at this sensitivity level)
* Bad news - low-frequency 1-Hz combs remain, and some new low-frequency combs & lines have appeared 

Some details:

 I initially looked at 15 hours of 30-minute FScan DELTAL_EXTERNAL SFTs (30 SFTs) generated during ER9 and was aghast at how bad the low-frequency spectrum looked, with a pervasive 0.485308-Hz comb ranging up to its 446th harmonic at 216.4 Hz, but when I exclude the three hours of SFTs when the 2-second ALS- glitches were present, things don't look quite so bad (see figure 1 for a sample without removal and figure 4 with removal). I dewhiten according to the new 6-pole / 6-zero, 0.3 / 30 Hz algorithm.
 The infamous 16-Hz comb due to the OMC length dither tracked down and killed here is gone (at least at this sensitivity level and these SFT statistics). As a result the high-frequency band (up to 2 kHz) is remarkably smooth with only violin modes and sporadic isolated artifacts.
 The 1-Hz comb with 0.5-Hz offset remains pervasive, but other prior 1-Hz or near-1-Hz combs with different offsets (e.g., 0.25 Hz) are not strong.
 On the other hand, there is a new near-1-Hz comb (0.996798-Hz spacing) visible to its 204th harmonic at ~203.3 Hz.
 There is also a new near-2-Hz comb (1.999951-Hz spacing) visible on approximate odd-integer-Hz frequencies, starting from ~9 Hz and visible up to ~175 Hz. This is likely the same 2-Hz comb reported in May by Bryn Pearlstone (which Ansel Neunzert kindly reminded me about today). 
 There is a "new" 56.8406-Hz comb visible to its 11th harmonic at ~625.25 Hz, which in hindsight I can see was buried in the O1 spectrum (I overlooked the pattern and indicated the teeth as isolated lines). This time the pattern was strong enough to jump out at me and to jog my memory that this comb was seen in  H2 1-arm data in 2012 in both the arm feedback channel and a quiet sensor-noise-dominated OSEM channel. This seemed to indicate a DAQ system problem at the time. I can see from O1 NoEMi line lists that this comb is pervasive in ISI, SUS and PEM channels at the corner station and both end stations.
 The old "K" comb-on-comb (0.088425-Hz fine comb attached to teeth of a coarse 76.3235-Hz comb) has more 11 more fine teeth visible on the lowest-frequency coarse-tooth comb.
 The old calibration line at 35.9 Hz has been moved to 35.3 Hz. The new excitation lines at 33.7 and 34.7 Hz are easily visible, but not as strong as the primary calibration lines. I found these changes documented here.
 There are sporadic new isolated lines here and there (indicated in line list - see below)
 There is a "crab-killer" broad bump centered at about 58.6 Hz which degrades sensitivity in the Crab Pulsar band of interest (~59.3 Hz). On the other hand, the whole noise floor is elevated w.r.t. O1, anyway. So it may be premature to worry about the bump.


Figure 1 - spectrum for 50-100 Hz when the 3-hour 2-second-glitches stretch is included (~0.5 Hz lines marked with 'h' for 'half')
Figure 2 - 0-2000 Hz (removing 3-hour bad stretch from here on)
Figure 3 - 20-50 Hz sub-band 
Figure 4 - 50-100 Hz sub-band 
Figure 5 - 100-200 Hz sub-band
Figure 6 - 1300-1400 Hz sub-band (illustration of how clean the high-frequency band is)

Also attached are a larger set of zipped sub-band spectra and a lines list (excluding the bad 3-hour stretch). Note that because the statistics here are two orders of magnitude smaller than used for the full O1 run report, I am not yet removing lines seen then that may yet re-emerge with more accumulated post-O1 data. So many of the line labels in these figures are buried in the noise fuzz for now.

Line label codes in figures:

b - Bounce mode (quad suspension)
r - Roll mode (quad suspension)
Q - Quad violin mode and harmonics
B - Beam splitter violin mode and harmonics
C - Calibration lines
M - Power mains (60 HZ)
O - 1-Hz comb (0.5-Hz offset)
o - weaker 1-Hz and near-1-Hz combs (various offsets, including zero)
H - 99.9989-Hz comb
J - 31.4127 and 31.4149-Hz combs
K - 0.088425-Hz comb-on-comb
t - 1.999951-Hz, 2.07412-Hz and 2.07423-Hz combs
D - 56.8406-Hz comb
x - single line (not all singlets in the vicinity of quad violin modes are marked, given the known upconversion)