(Keita Daniel Jim)

We copied the auot-centering logic from the green WFS to POP_X. The centering loops will be automatically engaged, when the NSUM threshold of the DC channels is above 0.5. It uses the integrator modules to add offsets at the output. The loops were adjusted for 10 Hz bandwidth.

I used diagnostic breadboard (DBB), with ISS first loop on and DBBPMC (not real PMC) unlocked, to use the DBB WFS DC output as the jitter sensor.

Right column is with the frontend beam into DBB, and left is with high power laser beam. QPD_[12]Q[XY] means WFS[12] DC [YP], and QS is the DC sum. I pressed "pre-align" so the beam comes to the center of the sensors, and the measurements were made while the pre-align servo was on. The total power for both of the beams sampled are about the same.

As you can see, the frontend beam is much quieter than the HPL beam over the entire measurement band, it's a factor of 40 or 50 larger at 100Hz.

The coherence between the HPL jitter and intensity to the PMC transmission RIN is large for the entire band (left bottom). Blue and brown show PIT to intensity coupling. Pink and cyan show intensity to intensity coupling. The fact that the coherence is high for PIT (Y) but not for YAW (X) means either the alignment into PMC is off in PIT, or some other jitter-intensity conversion mechanism e.g. clipping or QE dependence on the beam position is worse/steeper in PIT.

Just to see how this is different at different measurement point, orange and black are the PIT to intensity and intensity to intensity coupling measured by (one of the?) IO diodes downstream of the main EOM. (I know nothing about the analog filtering of this diode.) There's some but not huge difference in PIT-to-intensity coherence. Probably PIT-to-intensity conversion mechanism is more or less common to these two, e.g. alignment into PMC.

The antiwhitening filters for POP_A_LF and REFL_A_LF did not correspond to the analog whitening on the chassis in ISC R4.

• POP_A_LF had no whitening, but the digital SFM had two antiwhitening filters engaged. I turned both whitening filters on. This makes the dark spectrum a factor of 2 or so above the ADC noise.
• REFL_A_LF had no whitening, but the digital SFM had one antiwhitening filter engaged. I turned off the antiwhitening filter. We should re-evaluate whether we want to turn on some whitening.

ISS has been oscillating at around 1.x kHz since 6:30 AM or so (first attachment). This happens once in a while and no fundamental cause has been identified yet.

Anyway, I disabled ISS and turned it on again for recovery, and in doing so I found another familiar failure mode caused by the diffraction power set too small (H1:PSL-ISS_REFSIGNAL was set -1.7).

Whenever AOM hits the bottom, ISS receives a huge kick and the AOM output goes very high, and for whatever reason it comes down very slowly and eventually settles. I wonder if this slow impulse response is an intended behavior or not. Anyway, whenever you enable ISS this happens at least once, it seems. If the diffraction power is set too small, the AOM will hit the bottom again, and the process repeats itself (second attachment). If you start with a higher diffraction and then slowly bring it down, it will work for a while until a big intensity glitch hits.

The third attachment shows the ISS first loop with barely large enough diffraction (H1:PSL-ISS_REFSIGNAL= -1.64, which resulted in 10+ percent of mean diffraction) for the intensity noise as of now. The servo was turned on at t=-190 sec or so on the plot. You can see how frequently the servo gets close to bottoming out.

I increased the diffraction further (fourth attachment, H1:PSL-ISS_REFSIGNAL=-1.6) and adjusted the offset.

J. Kissel

While in the systems meeting today, we'd wondered if the PSL IO Chassis had any spare DAC channels available for use with the newly planned ISS 2nd loop upgrade (see D1600175). Though a PSL DAC channel list is available (see T1200092), it's not really organized to nicely answer the question. As such, I've gone through the PSL front-end simulink models in an attempt to better answer the question. In summary, there are 11 spare DAC channels, some of which are grouped in such a way that they might have independent AI chassis spigots such that installation of new channels for the proposed upgrade to the ISS Second Loop electronics should be easy. 

There are 4, 16 channel DAC cards in the PSL IO chassis. 
On DAC 0 (card_num=0), which is nominally the ISS DAC card, there are no spare channels.
On DAC 1 (card_num=1), which is nominally the FSS DAC card, there are SIX spare channels.
On DAC 2 (card_num=2), which is nominally the PMC DAC card, there are FIVE spare channels.
On DAC 3 (card_num=3), which is nominally the DBB DAC card, there are no spare channels.
Note I say that these DAC cards "nominally" associated with a given function and/or top-level front-end model, but there are many other instances (namely SEI and SUS models) where not only are there multiple DAC cards in a given model, but there even instances where different models share (obviously different channel on) the same DAC card.

The spare channels are specifically (where channel counting starts from 0)
DAC_1_8
DAC_1_9
DAC_1_10
DAC_1_11
DAC_1_13
DAC_1_14

DAC_2_0
DAC_2_12
DAC_2_13
DAC_2_14
DAC_2_15

I attach a full list of the DACs channels identified by their channel names (which hopefully is a good enough proxy for their use). I would attach screenshots of the models, but the output ports are labelled too poorly at the top level for it to be helpful.

PS. This is the first time I've had to look at these PSL models: 
- There are lots of wasted channels (many cases of EPICS records being fed into full filter banks -- likely just to get a fast-channel test point -- the need for which I don't understand). Cleaning this up would likely make a non-negligible impact on the model speed. Admittedly, only DBB model is running close to its limit using ~70% of clock-cycle for computation.
- the labelling of input and output ports makes following signal paths very difficult
- the use of buses and tags would greatly improve the readability of the diagrams
In short, it appears that these models just haven't taken advantage of any of the modern RCG features and experience to improve efficiency and legibility.

ISCT1 Mad City Labs (MCL) PZT Driver (for POP AIR) Moved 

This Driver was on the south (crane coordinates) end of enclosure roof.  It was moved to the north side.  This required making a new Power cable (Thanks Manny/Fil) & barrel-ed some BNC extensions to the BNC.  I did not touch the DB9 cables, but they are labeled and dangling out of the south wall for now.

Covering ISC/IO Enclosure Holes (this was done yesterday)

Peter K asked me to cover some small holes on the ISCT6 Enclosure.  I went ahead and checked all the enclosures and covered holes with foil tape to the best of my abilities (so some roof panels and some chamber-side panels might have been passed over, but as noted, these are small holes.)

The IMs in HAM2 shift alignment after the HAM2 ISI trips, and as part of my investigation into the alignment shifts, I counted the number of ISI trips in a year.

Interestingly enough, Hugh and I both estimated 20-25 ISI trips in a year, however the number is much higher, at 94.

What I also discovered that in Commissioning Mode, the ISI trips an average of 10 times / month, while during the O1 run, the ISI trips an average of 5 times / month.

Since H1 was not vented, it's expected that the IM alignment shifts will continue through O2, and we can expect 5 times / month while in the science run.

The h1asc model was rebuilt and restarted this morning to correct a channel naming issue, then the DAQ was restarted at 9:32.

SEI - nothingn to report. Hugh and Jim waiting for wind to pick up to work on filter blends.

PSL - back up after another chiller failure

VAC - nothing to report

CDS - no work to do on the floor today. There will be an ASC FE and DAQ restart at some point today

FAC - cleaning at MX this morning. Beam tube sealing is ongoing

COMM - modifying POP B photodiode in EE Lab

Attached are two files showing the warm up phase of the pre-stabilised laser, after finding the laser was
off due to a chiller fault - as noted in Jeff's entry from last night.

    It takes the pre-modecleaner about 10-15 minutes to warm up and come to its final alignment, during
which the transmitted power slowly increases.  Other powers follow suit.  One can also see that as the
pre-modecleaner settles in, the beam position as monitored by the power stabilisation quadrant photodiode
slowly settles in too.

Title:  05/17/2016, Evening Shift 23:00 – 07:00 (16:00 – 00:00) All times in UTC (PT)
State of H1: IFO locked at DC_READOUT with 2w of power.   
Commissioning: Several commissioning tasks underway.
Outgoing Operator: Ed
 
Activity Log: All Times in UTC (PT)

23:00 (16:00) Start of shift
23:45 (16:45) Sheila & Haocun – Going to IOTC1
00:10 (17:10) Sheila & Haocun – Out of LVEA
01:01 (18:01) Sheila & Haocun – Going to IOTC1 
01:43 (18:43) Sheila & Haocun – Out of the LVEA
01:46 (18:46) Sheila & Haocun – Going to IOTC1
02:18 (19:18) Sheila & Haocun – Out of LVEA
02:25 (19:25) Sheila & Haocun – Going to IOTC1
02:53 (19:53) Sheila & Haocun – Out of LVEA
03:17 (20:17) Sheila & Haocun – Going to IOTC1 
03:22 (20:22) Sheila & Haocun – out of LVEA
05:19 (22:19 Lost Lock – PSL down with Crystal Chiller flow sensor error


End of Shift Summary:

Title: 05/17/2016, Evening Shift 23:00 – 07:00 (16:00 – 00:00) All times in UTC (PT)
Support: Jenne, Sheila, Haocun, Evan
Incoming Operator: N/A 

Shift Detail Summary: IFO has been mostly locked at various stages during the evening shift while commissioning work ongoing. At 05:19 (22:19) Lost Lock due to flow sensor error on PSL Crystal Chiller. Commissioners going home for the night.  

   At 05:19 (10:19) Lost lock due to PSL shutdown. X-Chiller down with Flow Sensor error.  

Haocun, Sheila, Keita, Jenne

We spent some time today on the POP X path, hoping that we can use this to avoid the locklosses we had last night due to sign flips in the REFL WFS signal for PR3.  

• First Haocun added a 50/50 beamsplitter to the POP air path, which reduced the light on both the POPAIR A and B diodes.  This means we don't have to be afraid of damaging POPAIR B at 50 Watts.  She then realigned both of these diodes, although we haven't checked the camera.  Jenne increased the whitening gain to account for the factor of 2, and redid the dark offsets so that we could relock PRMI.  With PRMI locked Haocun and I aligned the rest of the path to POP X, which is about 5 inches shorter than the path at LLO based on the table diagram.
• We had some trouble using the MCL PZT, with help from Keita we understood that the problem was with using long d sub cables.  Apparently, the sensors used in the internal piezo servo don't work if the cables are too long.
• Once the PZT was working, we designed a simple servo 1/f with a ugf around 1.5 Hz and the centering loops locked up imediately.  Haocun has open loop gain measurements that she will add.  
• We then quickly looked at phasing the RF by dithering PR3 pitch.  The laser turned itself off while we were doing this.   

Looking at the centering servo, Daniel and Keita realized that it would be nice to modify the model to have the same kind of integrator and triggering we have for the end station PZT servos, and modified the model.  It would be good to restart the ASC model to incorporate these changes, which will require a DAQ restart so we didn't do it tonight.  I cleaned up SDF so that it is ready to go if there is a convient time in the morning.  

[Sheila, Jenne]

These are numbers pulled from our dP/dTheta measurements from last night (mentioned in alog 27235).  I have gotten the numbers into RIN/theta, since we want to know how much the power fluctuates for a given angular motion of an optic.  The short summary is that the Yarm optics affect the power fluctuation much more significantly than the Xarm optics do, and that the ETMs affect the power more than the ITMs. 

Sum up of 2W results:

We'd like to remeasure these values at different powers - hopefully they're constant.  Of course, these are relative power fluctuations versus angle, so the overall force on the optics will be increasing as we increase the power.

The following table with more detailed results has a crazy-town amount of information, some of which I'm not totally sure what to do with yet.  The difficulty is that since we have ASC loops running, when we dither one test mass, all 4 test masses move.  So.  Here's the gory detail.  All dithers were at 0.51 Hz in pitch to the L2 stage of the test masses. Start times are UTC of 17 May 2016. The values in the table below are at our 0.51 Hz dither freq.  The numbers in the summary table above are the RIN of POP_A_LF versus the angular motion of the optic we were driving at the time.

BP

Following Friday night's lock, I looked at the spectrum and saw some regular structure, looking like a 2Hz comb at odd frequencies.This looks like a new comb. [figs 1&2]

As followe up, I ran coherence with all of the EBAY magnetometers and saw strong coherence is some places with this 2Hz comb, as well as the persisting 0.5Hz comb (see plots below)

0.5Hz comb: https://ldas-jobs.ligo.caltech.edu/~brynley.pearlstone/comb_investigations/May_2016_comb/H1:PEM-EX_MAG_EBAY_SEIRACK_Z_DQ_25_40Hz.png

0.5Hz comb + 2Hz comb: https://ldas-jobs.ligo.caltech.edu/~brynley.pearlstone/comb_investigations/May_2016_comb/H1:PEM-EX_MAG_EBAY_SEIRACK_X_DQ_25_40Hz.png

Note: These two are the same magnetometer (MAG_EBAY_SEIRACK), looking at 2 different axes. Both combs were also seen in other magnetometers.

Full list of plots: https://ldas-jobs.ligo.caltech.edu/~brynley.pearlstone/comb_investigations/May_2016_comb/

Previous efforts to mitigate the 0.5Hz comb was focussed on powering the timing card independently in the CS EBAY LSC-C! I/O chassis which handles DARM. This has not worked to eliminate the comb. I can't report any reduction yet, as Friday's lock was not sensitive at low (<100Hz) frequencies.

This 2Hz comb on 1Hz offset is the transform of a 1Hz square wave. The 2Hz comb might have to do with the 0.5s and 1s structure seen it Keith's data folding studies here: https://alog.ligo-wa.caltech.edu/aLOG/index.php