(All times are local Pacific Standard Time)

Summary:

PSL crew worked in the PSL room in the morning and then H1 was available for locking and commissioning.

SEI Notes:

• SEI group have been working on Guardian, BRS/Sensor Correction stuff, and the ISI Blend medm (on nuc0).

H1 Locking Notes:

• Attempted locking mid morning and locked DRMI, but it dropped shortly after.  Sheila/Jenne later noticed a bad alignment and requested an Initial Alignment; made it to INPUT_ALIGN, and found issues with locking the X-arm in IR (There were people in the H1 PSL room.  Sheila also made a filter/gain tweak to the LSC XARM filter bank.)
• After H1 had an Initial Alignment, DRMI and PRMI looked ugly.  Traced (Thanks, Sheila!) bad alignment to the PRM's yaw (since misaligning the PRM and tweaking the BS while in PRMI looked fine.)
• At one point, IMC_LOCK Guardian had a FAULT, with TJ's help and also Cheryl's alog, toggled the FSS AUTOLOCKER button off & on.  Know you are good when (1) the TPD DC Output is on the order of 3 Volts or more (was getting 0.8V the first few times), AND (2) there are no oscillations on the PZT MON graph on the FSS medm.
• Finally made it to DHARD WFS.  Roll Modes looked OK, so we did not engage them.  Slowly moved through the ASC Guardian states & eventually made it to DC_READOUT_TRANSITION.

Day's Activities

• 8:11 Dust Monitor Cabling near H1PSL rack (Jeff)
• 8:50-10:00 PEM Cable work (Fil)
• 8:51-9:47 Vertex RGA bake start (Kyle)
• 9:17 LVEA entry for Scroll pump info (Joe D)
• 9:26 Needs to make tape-measure measurement (Chandra)
• 9:50 PSL Measurements, working on Diagnostic BreadBoard, for the morning  (Peter, Jason)
• 10:30 Checking on TCS Enclosures (Fil)
• 11:33 Checking PSL rack (Keita)
• 1:02 PSL Dust Monitor Alarming begins
• 1:45 Vertex RGA check (Kyle)
• 3:10 Cleaning Area visit (Travis)
• 3:20 Measuring valves at MX (Gerardo)

rpn3.png shows 3 relative power noise spectra taken today with the power stabilisation
locked with the gain slider at 6 dB - with and without the integrator - and at 9 dB,
after yesterday's alignment tweak into the pre-modecleaner and re-aligning of the
photodiode box.

    As can be seen the integrator has little if any effect.




Jason, Peter

By popular demand, I have added a FE_STATUS legend to the CDS overview medm screen. This is slightly different from the STATE_WORD bits shown on the GDS_TP screens, so a legend is indeed useful. The first 9 bits match, I have dropped the OVERFLOW bit, shifted the CFC bit one left and added the DAQ (as seen from the DAQ) bit to the end.

The legend is a related display, please use the "SHOW LEGEND" button at the bottom of the overview screen.

Corey again had trouble with the XARM IR not locking today, and Jenne found that the optical gain seems to be 10dB higher today than it was on May10th 27082.  We compared the power on ASAIR LF which had a change in power which was small compared to the dark offset, and the position on AS_C, which had moved in pit from -0.9 to 0.  However, Jenne moved SR2 around to mimic these changes, and saw no change in the loop gain.  So it seems like we have a 10dB gain change that we don't understand.  

As a way of getting around this, I edited the filters in XARM IR to make our phase bubble a little bit wider, moving both kHz poles to 2kHz and moving a zero from 30Hz to 10 Hz.  A comparison of the filters and the OLG is in the attached screenshot.  We have lowered the digital gain in the guardian to 0.05 again.  

I have written a simple script called which_models_are_using_this_file

It takes one argument, the name of the file either as a full path or name only, and reports all models which use that file. This will allow a source file change to be propagated to all models which use it and prevent possible surprises the next time a model is built (e.g. during an RCG upgrade).

> which_models_are_using_this_file /opt/rtcds/userapps/release/cds/common/src/LOW_FREQ_MUX.c
Models which use file: /opt/rtcds/userapps/release/cds/common/src/LOW_FREQ_MUX.c
h1omc
h1pemex
h1pemey
 

The FMCS screens which appear on the MEDM web view have been modified to include a date and time string.  This should provide offsite viewers some assurance the data presented is current.

A side effect of this is the screens as viewed from the vacuum controls workstations will have a white block where the date and time string is, similar to what is shown on the vacuum screens on those workstations.  

Josh, user EcceruElme from GravitySpy beta, Andy

User EcceruElme in the GravitySpy beta (a citizen science effort to classify detector artifacts) identified a new glitch class. They pointed out here that the glitches are not quite periodic, but the shapes seem to alternate - first upwards, then downwards. See the first plot.

One time when this happens is Dec 12 at 21:31 UTC. Looking at more time, we realized that these are nearly periodic when you treat them as coming in pairs - first an upward glitch, then downward. The pair have a spacing of about 2.5 sec (or 0.4 Hz). The glitches go on for minutes, and then the lock ends.

Comparing to a time earlier in the lock, several mirrors develop a big peak in pitch (and to a lesser extent length) motion around 0.4 Hz, as witnessed by the OSEMs. We see this motion in the beamsplitter, SRM and SR2 but not SR3, and in the OMC tip-tilts and the OMC suspension. The BS has a pendulum mode in length at 0.4193 Hz and in pitch at 0.4683 Hz. So it seems most likely that this resonance got rung up somehow, and then SRM and SR2 are following this to try to keep the beam pointed toward the tip-tilts (SR3 is uncontrolled and has no movement). Then the three tip-tilts and the OMC are following that motion - there are two degrees of freedom to center the beams on the WFS, and two more to keep it pointed into the OMC, which is why all three tip-tilts as well as the OMC suspension itself all move. The second through fourth plots are the motions of the BS, SRs, and tip-tilts in pitch. The fifth plot is motion of various OMC DoFs.

It’s not clear why the beamsplitter is moving. It seems likely that the BS pitch resonance is the primary cause of the motion, but it may instead be tracking motion upstream. If the problem is the BS, maybe something is wrong with the local control or maybe some seismic noise is driving the resonance.

It’s also not clear yet exactly how this couples in. These glitches do not look like scattering arches - they are too high in frequency, have no support at lower frequency, and also there’s no top part of an arch. So it may be jitter, or clipping. The best prediction of the glitches is the pitch position of SR2 as seen by the OSEM. One kind of glitch happens at the maxima, and one at the minima. The final attachment shows this. But we haven’t looked at all channels yet.

Further work can be done by looking at other times when this kind of glitch occurs (GravitySpy can provide those), looking for the cause of the BS motion, and trying to find which of the alignment channels is the best predictor of the exact glitch times.

Measured both the filtered and DC output of the power stabilisation photodiode, a measurement
that was limited at low frequencies by the noise of the SR785 (S/N 77457), which seemed to be
somewhat higher than normal.  The broad peak at ~45 kHz present is not present in the bias
voltage, nor the power supply voltages.  The photodiode showed no visible signs of damage.  As
a result I was reluctant to remove it from the circuit, plus it had the glass window taken off
which makes it even more prone to damage if one was negligent.  The filtered noise is consistent
with the gain of 400 from the DC output.

  PDTF2.png shows the measured transfer function from the test point TFIN out to the test point
X5 and the filtered output.  Both are as they should be.

  Removed some extraneous flux from both sides of the circuit board, re-assembled the photodiode
box and then re-installed it on the table.  The sample output of the pre-modecleaner was aligned
onto the photodiodes by peaking the DC output.  The beam onto the internal quadrant photodiode
was then re-positioned to zero the X and Y outputs as best as possible.

  The alignment into the pre-modecleaner was tweaked to try and minimize the free-running
peak-to-peak fluctuations.  The power incident on the photodiodes was adjusted so that the
filtered output was not saturated.  This seemed to be with a DC output of ~7.5V.  Then power
stabilisation was then engaged.  Further alignment tweaks for the pre-modecleaner are probably
warranted.



Jason, Peter

State of H1: locked earlier, even showing a range, but earthquakes in the last 2 hours are preventing lock

On site: Commissioners Sheila and Evan, Operator Cheryl

Activities:

• PSL temperature changed behavior yesterday, Sheila went out and checked on it's HVAC system, it seems to be recovering
• our clue to PSL temperature issues was a series of dust alarms (low at ~50 counts) starting around 1PM PT today which now have cleared up
• dark offsets were checked/changed
• guardian left in Down

Sheila, Evan, Cheryl

With the ISS engaged were able to lock fine.  

• We moved the SRC ASC engage to after the refl wfs loops come on (PR3, IM4, CHARD).  This was because the SRC1 Pit loop was unlocking the IFO when we were engaging it first, and we noticed that turning these loops on (as well as the soft loops) moved the error point for AS36 WFS alot. 
• The OMC length dither demod phase seems to have changed.  It has been 0 throughout all of O1, and is now set to 110.  We don't know if this is a sudden change due to something that happened, or a long term dirft that has been happening througout O1, but today the demod phase was wrong by enough that the error signal sign was flipped.  The last mention of checking the demod phase I could find was from Dan Hoak, 18130
• Once we got to DC readout, we checked for coherence with several sensors for intensity noise and jitter, and didn't see much coherence at all (screenshot).  
• Taiwan EQ kocked us out around 4:12 UTC May 12.  This might be an interesting lockloss to see what we will need to do to ride out EQs better.
  • The roll modes got rung up, which might be because the alignment was fluctuating too much and changing the phase of the damping loops.  We could consider just leaving the damping off in low noise, or if we do get an EQ warning in EPICS, we could use it to turn off roll mode damping when an EQ comes. 
  • We need to increase the offloading speed of our arm ASC loops, which together with the rung up roll mode were saturating L2.

Peter and Jason have just come out of the PSL.  I will let them log their work in there.

But, the 3 of us were just sitting with Evan, and looking at our latest PSL RIN.  It's unclear why there's a difference, but the RIN straight out of the HPO seems better now than it was previously.   The first screen shot shows this, in that the blue traces for the PSL-PWR_HPL_DC_OUT is lower now than the equivalent traces in alog 26773.  On the first screen shot, references are with the integrator off, current is with the integrator on.  But, the ISS seems to not be doing anything, so we're not seeing a change when the integrator comes on, in the after-ISS PD.

The RIN into the vacuum is not very good (red and pink traces on the first plot).  The second screen shot shows the RIN into the vacuum now with the ISS on versus 00:00:00 11Feb2016 with the ISS inner loop on.  It's pretty clear that we're not getting the same RIN as we were during 01 with the inner loop closed. 

Cheryl has already started the locking sequence for us, so we'll give things a try for the night as-is.

The new RCG3.0 has the ability to report the differences in filter files which have been modified but not loaded. In other words, it a modified filter file is detected, it tells you what would be added/deleted if you were to load the filters.

The !Diff button next to the "Modified File Detected" status opens an xterm which displays the differences. The lines are marked with preceding arrows and are color coded.

Right arrow ">" and BLUE are lines which will be REMOVED when the filters are loaded

Left arrow "<" and MAGENTA are lines which will be ADDED when the filters are loaded

As a test example, I modified the H1PEMMX.txt filter file and deleted the line "# MODULES" and added a line at the end of the file "# this filter will be added when coeff load is pressed". The resulting diff listing is shown below.

liquid levels have been oscillating all day in PID mode, with gain lowered from 6 to 5. I just lowered both to 4 and will test in PID mode overnight.

11:45 am local

1/2 turn open LLCV bypass valve. Took 12:00 min to overfill CP3 today at 20% LLCV open. 

Related log(s): 21131

Summary. - Today, I have updated the first anti-whitening filters of the OMC DCPDs in the OMC digital front end model in order to make them more accurately match the actual analog circuits. The attached show screenshots of the foton filters before and after the update.

Impact. - The new OMC DCPD responses are different from what they used to be by 1% at 10 Hz in magnitude and almost no change at 100Hz and above. The O2 DARM model must take this update into account. Note that even though the qualitative behavior of the mismatched anti-whitenings is similar to the large bias we have been seeing in the DARM response (for example 24569), they do not explain the bias (which is about 10% at 10 Hz in magnitude).

DCPD balancing. - According to my calculation, the balancing should be good at a 0.1% level without introducing an artificial imbalance in the OMC front end. So I removed the existing artificitial imbalace (-0.3%) and update the OBSERVE and DOWN SDFs. However, the imbalance should be experimentally double-checked and possibly re-adjusted.

Jeff K, Evan G

We (finally!) measured the ESD driver quadrant control voltage path transfer functions, which was needed because of the change made on Feb 9 (see ECR E1500341 and LHO aLOG 25468) for calibration/compensation use. Measurements are stored under 

/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER9/H1/Measurements/Electronics/2016-05-06

Measurement notes attached. Analysis to come...