Times in UTC (PST)

15:15 (8:15) Karen opening rollup door in receiving.

15:54 (8:54) Fil to roof.

17:00 (10:00) Fill off roof.

17:11 (10:11) Jason, Ed to optics lab.

17:26 (10:26) Kyle, Gerardo to Y28 port on Yarm

17:48 (10:48) Gerardo back from Y28

17:57 (10:57) Gerardo to EY to look at a wireless card

18:30 (11:30 Kyle, Gerardo back

20:30 (13:30) Kyle, Gerardo to Y28

22:10 (15:10) John to Y28

Summery:

Locking this morning wasn't too sucessful, it would drop lock at ENGAGE_ASC every time in what seemed to be the same place. Jim W and I decided to run that state by hand in a Guardian terminal. Doing this showed that changing matrix elements in ASC input yaw, for SRC1 from AS_B_REF36I to AS_A_REF36I was dropping the lock. We got Gabriele involved and he saw that the error signal was no longer good for AS_A. Gabriele and Sheila have changed some things around and it seems to be holding lock now though!

A follow up on how the "new" old, slower FE computers have been running from Jim Batch:

If you trend H1:FEC-88_CPU_METER over the last 45 days, you can see 
what the h1susetmx was using before we installed the new "faster" 
computer, and when we reinstalled the original computer. 

After the "faster" computer was installed, changes were made to the
model which increased the amount of time the model uses, so now it is
over the limit frequently. 

On the DAQ test stand, we removed a portion of the changes that were
made which only calculated values and reported them with EPICS
channels.  That can be done in the corner station instead of sending 
the signal to the end station to be calculated.  The saving was 
3 to 4 uS which is enough to keep the model running under the max 
limit most of the time.

ECR E1500376 has been filed to move violin mode monitoring channels off of these machines and into the OAF one.

The Butterfly and Drumhead modes of various optics are summarized below.  This is taken from work performed by Calum, etal (CIT) in T1500376 on most optic types, and Slawek (MIT) in T1400738 on the test masses.

Note, I have only summarized the x-polarized butterfly mode because all of our drives to optics are along that axis, not the +-polarized direction.  It would be hard to drive the +-pol mode so we don't think we'll see them anyways.  As well, the modeled x-pol is the same freq

First attachment: Coherences are huge berween TMSX IR QPD SUM, PIT and YAW for 100>f>8Hz in full lock. So many peaks. These appear only when the beam is on QPD.

TMSY QPDs, though not featureless, don't show much coherence and the noise is almost featureless for f>8Hz.

Though X QPDB YAW doesn't show coherence with SUM in this specific plot, this is not always the case (at other times other DOFs loose coherence). Seems like this is dependent on either IFO alignment or TMSX alignment or both.

IN1 of each segment is about 10k counts maximumin full lock, far from saturation.

SUM bump at around 9Hz  is about 10^-5 RiN/sqrtHz.

Second attachment: All segments have the same structures. (16Hz peak is probably the roll mode.)

This is in RF full lock, 2.2W, and the peaks look different from the first attachment (e.g. 12Hz bump is a lot smaller relative to 9Hz bump, there are 2nd, 3rd and maybe 4th harmonics of 9Hz bump).

The 9Hz bump is O(10^-5) RIN/sqrtHz again.

In both QPDA and B, seg1 and seg4 are larger than 2 and 3.

For QPDA, SEG1 is coherent with SEG4 (in-phase) but not with SEG2 and SEG3, while SEG2 is coherent with SEG3 (out of phase) for f>8Hz. SEG1 and SEG2 look kind of out of phase but the lack of coherence means that this doesn't mean much.

For QPDB SEG1 is coherent with SEG2 and SEG4 (1 and 2 in-phase, 1 and 4 out) but not as coherent with SEG3. SEG1 and SEG3 might be in-phase with the same caveat as QPDA SEG1 and SEG2.

(All of these may or may not depend on the alignment and IFO state.)

This doesn't make much sense. If it's TMSX hitting something and exciting mechanical resonances I'd expect some coherence between all segments at around bumps, even if there's some clipping.

If this is a simple electronics problem, different segments should not be coherent with each other.

Third attachment: When IR and green are resonant at the same time, for example the twin bumps at 9 and 12Hz or so for IR and green line up. But they are not coherent with each other (black trace at the bottom is the green QPD, black at the top is green/IR coherence).

Green QPDs are coherent with seismometers, IR QPDs are not. 

RIN of 9Hz bump for IR and green are on the order of 10ppm/sqrtHz and 1000ppm/sqrtHz, respectively.

TMS BOSEMs are too noisy to detect anything at this frequency (no difference between TMSX and TMSY in this regard).

Question: What are we seeing here?

This morning the lock acquisition always failed at the ENGAGE_ASC step. We traced down the problem to the change in SRC1_Y input matrix: the error signal was changed from 2 * AS_B_RF36_I to -3*AS_A_RF36_I. We tried this transition manually with -20dB of loop gain, and altought the loop was moving the rror signal toward zero, the result was a misalignment of the IFO and unlock.

So for the moment being I com mented out this matrix change in the guardian. ENGAGE_ASC is now stable with this configuration.

Looking over the past 3 weeks of data for the Laser Room temperature, the attached plot shows 4 deviations
from the norm.  The first two coincide with maintenance activities carried out by Jason and myself.  The
third from the left by Cheryl and Robert doing some IO work.  The fourth one from the activity this week.
Each incursion results in a change in the pre-modecleaner body temperature with perhaps the largest change
occuring this week.

Since most times we probably touch up the pre-modecleaner alignment a little, this probably masked the
effect of the pre-modecleaner body length change on the alignment.

This is a follow up to this entry about the excess noise in the EX TR QPD signals.  The OSEM fix did not help this, so they seem to be unrelated.  I looked at the PIT and YAW signals, and found that they are very coherent with SUM in the 5-100 Hz band where the excess noise appears (plot 1), and that the phase of the transfer function in that region is 0 (e.g., SUM, PIT and YAW all have the same sign and phase).  This appears to point to a problem in segment 1, though I cannot confirm that with offline data.  I looked at the OUT16 channels for all segment and didn't see anything obviously wrong (plot 2).  Interestingly, the same signal appears in QPD A and B, so this is not a single channel problem.

To do: investige the individual segment signal in the online data... is this just sement 1?

Most of the night IFO was with commissioners.

Earthquake about 2 hours ago kept us from relocking for a while.

IFO has made it through to Engage ASC a few times, so transition to CARM is ok.

I've been having the IFO sit in Engage ASC, which I thought was very stable, but it has not been this morning, and we have not had any locks that are long or that make it up to DC Readout+.

The main story of the day is related to the non stationary low frequency noise first seen early in the morning. It seems to come from CHARD noise, which could be coupling to DARM more now because of a change in alignment.   

• Once we were stable at 24 Watts this afternoon, we didn't see the terrible low frequency noise that was seen in the early morning (at least it was not as bad).  
• Jenne and I worked a bit more on the CHARD loops, adding 23 Watt boosts, a lead filter that gave us some phase to make cut offs.  The first attached screen shot is a comparison of CHARD PIT at 3 Watts, and at 24 Watts before and after the changes.  Jenne has similar measurements for yaw.
• The terrible low frequency noise came back.  
• We undid all of the CHARD changes we made yesterday and this afternoon(keeping only the leads and cut offs) .  The terrible low frequency noise did get better, although some extra non stationary low frequency noise remains below 50 Hz.  The non statinary noise was reduced when we did this, although we still had some excess non stationary noise below 50 Hz, and coherence with CHARD.  We did another round of on/off test to be sure CHARD was involved.  
• We decided to check on alignments that we thought moved durring monday's PZT power off and PSL temperature excursions.  We could see that we had moved on IM4 trans after monday, so in full lock we moved IM3 to bring ourselves back to the old location on IM4 trans.  
• We then redid inital alingment, carefully, and relocked, using the low bandwidth CHARD loops and our new cutoffs.  After this the noise does seem better, but there is still excess noise that is non stationary.  

A few ideas for next steps:

• see if we can find a better CHARD sensor.  Do we need to use trans mon QPDs or is there a way to find a better SNR on the refl WFS?
• can we do a better job with A2L?
• We could try to change our alignment to see if we can reduce this noise.
• DHARD resonant gain for the 0.46 Hz instability.  This instability only seems to come up when we have a bad alignment, but a little more gain can probably help us avoid it. 

We also worked on a few other things today...

• Between Evan and I we reverted the phase of the 45 WFS to what they were a week ago (before TCS tuning)
• Gabriele and I saw this morning that we think that a SRC1 YAW input matrix of -3 for AS A 36 I and no signal from AS B is good.  We watched all of the AS 36 Yaw signals as we powered up to 17 Watts, and saw that AS B sees something that drifts as we power up.  When we removed AS B from the input matrix, the AS 90 power increased.  
• The SRC2 Yaw loop was painfully slow (several minutes reaction time).  It now has a factor of 2 more gain (-40 is fm gain now, it was -20 before).  This is in gaurdian. 
• Gabriele had a look at doing frequency dependent A2L for ETMX.  We have reverted it for now, but it seemed promising. 
• Our locks today seem quite stable, we have been loosing lock by making mistakes, and when we have a combination of driven measurements and PEM injections.  
• ETMY ESD LP had been turned off at some point, most likely unintentionally.  It's on again, and now monitored in SDF.  We also turned the PUM coil drivers back to their low noise state.  We needed more range for DHARD when the roll mode was rung up very badly last week (because of DOWN not runnning for extended of periods of time twice.)  These were a mixed bag of monitored and not in SDF, I think I've set them all to monitored now, with the requested state as 3.  However, this gets over written by the gaurdian.  
• I had put offloading of full lock ASC in the normal guardian path, but this seemed to make the DRMI alingments for relocking worse (possibly because the full lock ASC is compensating for some wire heating).  So it is now removed from the normal path, but can be choosen as an option after transitioning to DC readout.  

I ran Hang's latest A2L script (see aLog 20013), after the realignment work that was done tonight (Sheila is writing up her entry as I type). 

We stil have excess noise at low frequency, but maybe there's a bit less than when I started the script?  The noise we're seeing is totally non-stationary, so it's hard to say.  Certainly the A2L didn't eliminate it.

After the PSL temperature adventure on monday afternoon, it seems as though the PMC alignment shifted.  We now get less transmitted power, although the sum of refl and trans has not changed much. 

I took a look at the scattering noise we see in all lock since last night .

I computed the band-limited RMS between 20 ans 120 Hz, and this is a good indicator of the scattering noise level. Then I looked at correlations with all suspension motions (using M0 and M1 signals, as Keita did for the OMC).

So I'm able to reconstruct the noise variation over time, using a linear combination of all the suspension signals and their squared values. However, I'm not able to pick point one single mirror which is moving more, as shown in the ranking of the most important channels for the BLRMS reconstruction.

I compared the suspension motion spectra from tonight (GPS 1123422219) and few days ago (GPS 1123077617). The most relevant difference is that all test masses YAW motion have now a large bump at 3 Hz. ITMY also has large lines at 0.45 and 0.63 Hz. Finally ETMY pitch shows a large line at 6 Hz and some excess noise above that frequency.

Not sure if all of this is really relevant...

I looked into the glitches created by Robert's dust injections. In brief: some of the glitches, but not all of them, look very similar to the loud glitches we are hunting down

Here is the procedure:

1. select all drops of the range in the two hours of injection
2. for each one, load three minutes of data, compute the 30-300 Hz BLRMS and find the glitch tims as the maximum of the BLRMS peaks

In this way I could detect a total of 42 glitches. The last plot shows the time of each glitch (circles) compared with the time of Robert's taps (horizontal lines). They match quite well, so we can confidently conclude that all the 41 glitches are due to dust. The times of my detected glitches are reported in the attached text file, together with a rough classification (see below)

I then looked at all the glitches, one by one, to classify them based on the shape. My goal was to see if they are similar to the glitches we've been hunting.

A few of them (4) are not clear (class 0), some others (14) are somehow slower than what we are looking for (class 3). Seven of them have a shape very close to the loud glitches we are looking for (class 1), and 16 more are less obvious but they could still be of the same kind, just larger (class 2).

See the attached plots for some examples of classes.