ETMY ring heater test results

[Team TCS]

Last night we ran a low power (0.5 W to upper and lower RH stages) long duration (3 hours) ring heater test on ETMY.

The ETM deformation is visible on the Hartmann wavefront sensor, and the change in spherical power is similar to an identical test we did on ITMY two nights ago.

The prism x and prism y values, a measure of the wedging seen by the HWS, indicate that there is some misalignment from the center of the optic, more in yaw than in pitch. This is shown in the middle plot of the first attachment.

The second attachment is a contour plot, comparing a reference time just before the ring heater was turned on, and a "current time" once the prism values had reached a steady state. The hole in the middle might be because I did not reset the frame rate after starting the Hartmann code?

Edit: The hole in the second plot is due to the scaling, set in the plot contour script. I've rerun the script on the h1hwsmsr computer, where TVo has added an autoscale option, the result is attached as the thrird plot.

Quick Check-in on H1SUSSRM M1 Saturations Causing Local Damping Loop Instability

J. Kissel
FRS Ticket 10805

At the beginnings of IFO alignment recovery in corner station, H1SUSSRM's top mass would saturate, cause local damping loop instability, and eventually lock-loss when the requested/required alignment drive (either from sliders or ASC DC centering loops) for cavity resonance was large (see e.g. LHO aLOG 42198).

Now that we're regularly locking the full IFO, with all ASC loops -- including that which drive SRM -- running, and we have a robust initial alignment system we've not seen this problem. As quantitative evidence, I attach screenshots of the M1 DAC output request during a recent lock stretch that had the conditions described above (2018-08-31 17:50 - 18:16 UTC), which shows the request, at its largest is in the 55k DAC count mean range, with a few 100 ct max and min deviation from that mean. Recall the SRM has 18-bit DACs in which each channel theoretically has +/- 2^17 = 131k counts (practically ~120k counts before non-linearity and intermittent saturations sets in), so we're only using up ~45-50% of the DAC range.

Attached are screenshots of the SRM M1 stage and ASC overview during the above mentioned lock stretch (1st and 2nd attachment, respectively), as well as 40 minutes of trend data that shows the DAC output for each M1 coil, and the requested output from the alignment sliders and (slow) global control (3rd and 4th attachment, respectively).

Anecdotally, the commissioning vangaurd has confirmed that they don't recall any recent occurrence of this issue.

I deem this evidence enough to close out the FRS Ticket.

Quick Check-in on SUS Coil Driver Monitor Screens

J. Kissel
FRS Ticket 10349

Stuart had identified a bug in the SUS Coil Driver Monitor screens at LLO (see LLO aLOG 38485) after he completed front-end / I/O chassis switcheroo that took place between sush2a, sush2b, and sush56 (see LHO aLOG 38827). He subsequently fixed the medm screens in April (see LLO aLOG 38510), and did so for all suspension types since it was identified to be a result of the added calibration filtering into the RMS IMON and VOLTMON paths in the library part 
/opt/rtcds/userapps/release/sus/common/models/
    FOUROSEM_MONITOR_MASTER.mdl. 

I'd apparently updated the screens locally on July 3rd,
    jeffrey.kissel@zotws10:/opt/rtcds/userapps/release/sus/common/medm$ ls -la */SUS_CUST_*_MONITOR_OVERVIEW.adl
    -rw-rw-r-- 1 jeffrey.kissel controls 147374 Jul  3 14:15 bsfm/SUS_CUST_BSFM_MONITOR_OVERVIEW.adl
    -rw-rw-r-- 1 jeffrey.kissel controls  16570 Jul  3 14:15 haux/SUS_CUST_HAUX_MONITOR_OVERVIEW.adl
    -rw-rw-r-- 1 jeffrey.kissel controls 214822 Jul  3 14:15 hxts/SUS_CUST_HXTS_MONITOR_OVERVIEW.adl
    -rw-rw-r-- 1 jeffrey.kissel controls 330694 Jul  3 11:54 quad/SUS_CUST_QUAD_MONITOR_OVERVIEW.adl
but didn't aLOG it. I log it here as proof that we have updated the screens here. 

Note, because some models haven't yet been compiled against the new version of FOUROSEM_MONITOR_MASTER.mdl (namely the ITMs and the BS), the RMS IMON and VOLTMON values on these models will remain white until we do so. We expect these remaining straggler bugs will resolve themselves during the RCG upgrade in mid-September.

I'm closing the ticket accordingly.

Launching ndscope from MEDM

Craig has written a python script to launch ndscope from MEDM via the 'Execute' pull-down menu (see attached image). After selecting the PV you wish to plot, ndscope is launched with this EPICS PV name as its data channel.

Please note not all filter module EPICS channels are acquired by the DAQ, specifically the switch settings (SW1,SW2) and the output monitor channel (OUTMON). If you select these PVs the ndscope screen with show a red banner at the bottom with an 'Invalid channel name' error.

If you find a non-frontend MEDM PV which is not in the DAQ but should be, please contact me and I'll add it to the appropriate EDCU ini file.

Improved engagement of ASC loops in full lock

Every time the ASC loop are engaged in full lock (ENGAGE_REFL_POP_WFS) we noticed a large drop in the recycling gain, arm powers and sideband powers.

I looked into the cause of this drop and found that

1. a good power level was recovered when the PRM angular controls were engaged (see the attached screenshot of previous ASC engagement transients)
2. the recycling gain was kicked off the maximum by an excursion of PRC2_Y, which did not have an integrator on for a long wait time

Therefore I improved the ASC engagement in two trials: first by moving the POP QPD loop into ENGAGE_REFL_POP_WFS (so that now the state ENGAGE_POP_QPD does nothing new) and then by moving the PRC2_Y integrator earlier.

Now the transition is much smoother, and we don't loose power anymore:

 

Quick look at the ISS

This morning I had a quick look at the photodiodes in the ISS photodiode box.  Before doing anything
I noticed that the diffracted power chart on the MEDM screen displayed a large (many percent) difference
between the minimum and maximum diffracted power.  The REFSIGNAL slider was at -2.02, which is the value
I seemed to remember where it was left last night.  PDB is used as the in-loop sensor.

    The DC output of PDA was measured with a multimeter to be -11 V.  MEDM reported a value of 5.02 V.
Which is inconsistent with the REFSIGNAL setting.  At this point ~2.8 W was diffracted.  I also noticed
that the output of the quadrant photodiode was quite different from what I remembered the previous day's
reading was (that's just a feeling, not an absolute fact).

    I asked Richard to check the DC power supply that powers up the AOM driver.  It reported as being fine.
I power cycled the AOM driver but the behaviour did not change.  The position of the beam on both PDA and
PDB checked out okay.  The AOM driver checked out fine about a month ago when problems with the ISS were
observed before.

    At this I would say that the problem is not related to optics, and that there is something intermittent
in the AOM signal chain.

Trend data for the AOM drive for the past fortnight is attached.  There is a large excursion
from ~midnight the 24th (06:40 8-25-2018 UTC), followed by one after my work on Tuesday.  The
electronics were not worked on, on Tuesday.

At the moment, the second loop ISS output enable switch is enabled without the first loop mis-behaving.
This is different behaviour to how things were as recently as yesterday afternoon.

    Trend data for some signals suggest it might be worth looking at the op-amps N20, N22, N29, N31,
N39, N30, N2 and N34.  With perhaps the most likely candidates being N32, N29, N2 and N34.  As I recall
the board does not have a silkscreen so identification of the chips requires a bit more than a cursory
glance.

HARD loop measurements, centering loops

Sheila, Georgia, Craig

• Earlier today we lowered the gain of DHARD Y by 6dB, which makes it more stable.
•  Attached are measurements vs models of DHARD P+Y and CHARD Y.  DHARD P matches the model pretty well, and we have been able to engage the boost that we use for powering up.  
• DHARD Y has the gain we need to engage the boost, but engaging the boost isn't stable.  
• For yaw CHARD and DHARD match each other fairly well, and neither matches the model very well around the resonances around 1.5 Hz.  Based on the comparison to DHARD, we should be able to use 20 dB more gain for CHARD, but we find that we are not able to increase the gain without an instability.  
• We are also still limited to a very low gain for CHARD P. 
• We tried turning the optical levers back on, but this hasn't helped the stability of the CHARD loops.  
• We are now wondering if our problem is a cross coupling with the AS centering loops, or another ASC loop.  
• Since we are thinking that a cross coupling with another loop is our problem with CHARD, we attempted to increase their gains in the guardian state ENGAGE_REFL_POP_WFS, where the only ASC loops engaged are MICH, DHARD, CHARD, INP1, and PRC2 (POPX-> PR2).  Here we still see that they are unstable.  While we were sitting in this state, we saw a slowly growing instability at nearly 10 Hz which we were able to reduce by lowering the gains of the refl centering loops.  
• We took measurements of all 4 refl centering loops at DRMI, all 4 of these measurements can be found in /ligo/svncommon/IscSVN/iscmodeling/trunk/ALIGOH1/ASC_loops/Measurements/DC_centering/
• For DC2P we also took a measurement on resonance before engaging any of the REFL WFS, and we can see that the gain is reduced compared to DRMI by 1dB at high frequencies.   The second set of 4 attachments to this alog are comparisons of the REFL centering loops at DRMI and on resonance. 
• After measuring the REFL centering loop we had a look at the AS centering loops and found that they had barely any gain.  Comparing to Gabriele's log we saw that the gain was reduced by a factor of 5, which happened on August 23rd.  We set the gain back up by a factor of 5 for all 4 AS centering loops. 

We need to turn the gain of the CHARD loops up before we can power up, but haven't been able to so far. 

3.6dB squeezing today!

Haocun, Sheila, Terry, Nutsinee

3.6dB squeezing, 6.3dB anti-squeezing, non linear gain = 3, fringe vis 98%.

(screenshot of squeezing and anti-squeezing relative to shotnoise).

Today we balanced the homodyne with 1mW of seed, optimized our fringe visibility (98.5% on PD1 and 97% on PD2). CLF started off at ~10uW, and temperature was optimized for the best non linear gain. We hooked up a spare phase delay to CLF to give us more range of relative phase to play with. With this we got 2.5 dB.

 

Later I went back to check on the error signal on scope XY plot. it wasn't elliptical (more like an elongated stop sign shape). Sheila suggested this was due to saturation. So I lowered CLF power going into the fiber coupler even more until the shape was elliptical. I didn't look at what 3MHz peak looks like. But it was enough to lock both LO and CLF. I probably could have lowered the LO if CLF wasn't saturating the demod board. I didn't check. 

 

We needed more phase delay so hooked up the one for OMC to CLF. So right now CLF phase delay comes from CLF phase delay box, spare box, and OMC box. This gives us a little more than 180 degree (combined with HD). CLF and HD phase delay alone can to a little less than 90 degree.  

 

OPO lock offset is still a problem. I suspect this could be due to the asymmetry cut off of the error signal that probably cuts and crosses zero before the transmission reaches the maximum. This can be fixed with a gain slider in the common path. Still need to find out of this offset is consistent every time or if it scales with power. Then probably let the guardian take care of it in the long run.

 

By the end of the day we ended up with 3.5 dB squeezing. Terry's rough calculation suggested we have a lot of phase noise. It's noise hunting time.

 

Here's the phase delay setting for the best squeezed, anti squeezed measurement:

(squeeze)

(anti-squeeze)

 

Next on to-do list:

- Install 34kHz notch. With this we can push to squash LO noise some more.

- Install the modified TTFSS board to lock mephisto to OPO. 

- Characterize all loops and optimize them for the best noise performance.

Sweet!

locking issues since tuesday

We continue to struggle with some of the problems that appeared after Tuesday's maintence period.  To summarize these issues:

• We are no longer engaging the CARM boost, with the boost engaged we would loose lock within a few minutes of transitioning to ANALOG_CARM.  This could indicate that the frequency noise is higher, or an instability in the IMC or FSS, Craig measured the IMC OLG which seems fine (alog 43733)
• We have an intermittent problem with fast glitches in the ALS X arm locking, which might be because of the PLL or noise that comes from the fiber. 
• We have frequently been losing lock in the final stages of the CARM offset reduction.  (The transition to REFL9/sqrt(TRX) and the final step to resonance.)  These locklosses can be avoided by doing an inital alignment, but it seems that this is less tolerant of small misalignments than it used to be.
• We can no longer engage the ISS 2nd loop. 
• The ISS 1st loop has been noisier since the PSL work on Tuesday and the 2nd loop cannot be engaged.  Peter King commented here that this is due to having the ISS second loop open and the switches enabled.  The 1st attached screenshot shows the problem, that the diffracted power has been noisier since Tuesday. The second attached screenshot shows that about a half an hour ago I disabled the input to the 1st loop, and the noise is unchanged.  
• Travis looked at conlog for differences in several systems, and found that yesterday afternoon someone changed the 1st loop gain and switched the PD from PDB to PDA.  Apparently no-one remembers doing that, so we switched it back today.

lockloss tool not working

We changed the indices of some states last night since we changed the order of SRC ASC and the POP QPD loop.  

This seems to have broken lockloss select.  Here is the error message:

sheila.dwyer@opsws13:~/Desktop/Locklosses$ lockloss -c channels_to_look_at_LSC.txt selec
/ligo/apps/linux-x86_64/gpstime/lib/python2.7/site-packages/gpstime-0.1.2-py2.7.egg/gpstime/__init__.py:150: RuntimeWarning: Leap second data is expired.
Run 'update_leapdata()' to download the latest bulletin from the IETF
  RuntimeWarning, stacklevel=1)
usage: lockloss [-h] [-c FILE] <command> ...
lockloss: error: argument <command>: invalid choice: 'selec' (choose from 'channels', 'list', 'select', 'plot', 'blrms', 'saturated', 'help')
sheila.dwyer@opsws13:~/Desktop/Locklosses$ lockloss -c channels_to_look_at_LSC.txt select
/ligo/apps/linux-x86_64/gpstime/lib/python2.7/site-packages/gpstime-0.1.2-py2.7.egg/gpstime/__init__.py:150: RuntimeWarning: Leap second data is expired.
Run 'update_leapdata()' to download the latest bulletin from the IETF
  RuntimeWarning, stacklevel=1)
Traceback (most recent call last):
  File "/opt/rtcds/userapps/release/sys/common/scripts/lockloss3.py", line 701, in <module>
    args.func(args)
  File "/opt/rtcds/userapps/release/sys/common/scripts/lockloss3.py", line 348, in cmd_select
    selected = select_lockloss_time(index=args.index, tz=args.tz)
  File "/opt/rtcds/userapps/release/sys/common/scripts/lockloss3.py", line 190, in select_lockloss_time
    times = list(get_guard_lockloss_events())[::-1]
  File "/opt/rtcds/userapps/release/sys/common/scripts/lockloss3.py", line 146, in get_guard_lockloss_events
    for t in find_transitions(GRD_LOCKING_NODE, t0, t1):
  File "/opt/rtcds/userapps/trunk/sys/common/scripts/guardutil_tmp.py", line 88, in find_transitions
    if i == lasti + 1 and i2s(i) != i2s(lasti):
  File "/opt/rtcds/userapps/trunk/sys/common/scripts/guardutil_tmp.py", line 57, in i2s
    return system.index(s)
  File "/usr/lib/python2.7/dist-packages/guardian/system.py", line 753, in index
    return self._data_for_key(key)[0]
  File "/usr/lib/python2.7/dist-packages/guardian/system.py", line 720, in _data_for_key
    raise KeyError("%s is not a state index" % key)
KeyError: '432 is not a state index'

The states that we changed around last night were numbers 433, 432, and 431 (there are only 2 states, only two of the three have ever existed).  We've gotten this error message for which ever of the three states no longer exist when we have changed the state numbers around to try to get this tool working again.  

ezca connection errors

We've had two more times this afternoon where the guardian has had ezca connection errors.  We spoke to Dave about it and he is planning to restart the guardian machine during tomorrows's12 o'clock commissioning meeting. Attached are two log screenshots. 

Ops Day Shift Summary

TITLE: 08/30 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: None
SHIFT SUMMARY:  More commissioning all day working toward power up and recovery issues from the previous maintenance day.
LOG:  See attached .txt file.

 

Green references set

[Sheila, Gabriele]

While in full lock and after having optimized and closed the soft loops, we reset the references for the green initial alignment:

1. changed the green QPD offsets to zero the green WFS signals
2. updated the green camera masks and set points

Soft loop optmized setpoint and closed

I moved the soft degrees of freedom to maximize the power in the arm cavities, and reset the transmission QPD offsets to match the position.

For reference here are the recycling gain and power levels averaged over 30 seconds:

H1:LSC-PR_GAIN_OUT            37.43
H1:LSC-TR_X_NORM_INMON 1308.5
H1:LSC-TR_Y_NORM_INMON 1369.9

The new offsets are

H1:ASC-X_TR_A_PIT_OFFSET         0.074
H1:ASC-X_TR_A_YAW_OFFSET       0.144
H1:ASC-X_TR_B_PIT_OFFSET         0.057
H1:ASC-X_TR_B_YAW_OFFSET       0.196
H1:ASC-Y_TR_A_PIT_OFFSET         -0.018
H1:ASC-Y_TR_A_YAW_OFFSET       0.053
H1:ASC-Y_TR_B_PIT_OFFSET         0.083
H1:ASC-Y_TR_B_YAW_OFFSET       0.151

We could close the loops using the guardian and I measured the step response, by adding a +0.03 offset to each of the inputs. Time constants are approximately (see attached plot)

DSOFT_PIT        35s
CSOFT_PIT        45s
DSOFT_YAW     15s
CSOFT_YAW     20s

The error signals are now reconstructed with the new sensing matrix

Weekly PSL Chiller Reservoir Top-Off

Added 200 mL to crystal chiller.  Diode chiller is OK.  Filters appear clean.

BRS Drift Trends Weekly

All looks good here: BRS-X is around -5000 (limits are +/- 13000) and BRS-Y was recentered  by Jim on Tuesday, leaving it at ~+10000 (its trend has previously been negative, so this should give it some extra headroom).  See attachments.

Better OMC Scan with SQZ SEED Beam

[Sheila, Haocun, Nutinsee, Terry]

Yesterday we also did a better OMC cavity scan with beams from squeezer.

 

Compared with last time, we used:

• SEED power input on ISCT6: 54.2mW    <--- high seed power for good alignment
• Green power  input on ISCT6 : 8.8mW     <--- lower green power to get rid of green depletion
• Temp: 51.63C     <--- higher dual resonance crystal temperature to get rid of NLG

 

The results are shown in the attachment.

• Input power from IR PD: 1.24mW
• Power in the cavity: 0.78mW

     ---> This tells us the propagation and loss from Faraday is ~7.34%. (SRM transmission = 32.34%)

In the Cavity:

• 00 mode: 90.4%
• 10/01 mode: 0.38%  --> The alignment is very good
• 20/02 mode: 8.2%    This is the loss from mode matching. (Keep consistent with the former measurements.)