For the past day or so the diode chiller temperature has been fluctuating by a couple of degrees with a period
of ~90 seconds.  The fluctuations are noticeable in the temperature of the diode box heatsinks, and in the
injection locking voltage for the oscillator.  Maybe not so noticeable in the output power of the oscillator,
and not in the diode box output power.

    The diode TECs are compensating for the temperature fluctuations.  Since the TECs solely adjust the temperature
of the laser diodes, the temperature fluctuations are clearly caused by the diode chiller.

SEI - Jim W needs to head down to EX to check on some PLC code.

SUS - Good.

CDS - HW: Whitening filter that was switching, see Sheila's alog (alog29925).

    SW: fw went unstable yesterday, investigation ongoing (alog29911).

PSL - Up and running.

Vac - Chandra will still run tests on CP4 when possible.

Reminder: ER10 will not start next week, pushed back to the end of October.

Following on from yesterday's diffracted power versus applied AOM RF power, the coefficients for the
parabola calculating the percent diffracted power has been changed.

old: 97.675 x**2 - 63.548 x + 11.458
new: 134.794 x**2 - 106.473 x + 20.9997

The calculated fit is only good for AOM drive values greater than 0.300V (which is almost always
the case, historically).

The transfer function of the first loop ISS was measured before and after the coefficient change.
The UGF was not affected.

    Attached are dumps of the MEDM screens taken before and after the coefficient change.  The before
and after transfer functions around the UGF are attached to show that no change in the UGF was observed.

Kiwamu, Lisa

After about 1h in the lock, the interferometer stabilized in a happy place. 

With the CO2X power at 240mW and the two ISS boost engaged, we performed some fine tuning of several parameters:

SRCL feed-forward gain adjusted from -1 to -0.9
MC WFS offset DOF1_P 170 (same value as Sheila found the other day) 
Coupling of the vertex length DOFs: POP 45 demod phase: from 64.8 dg to 77.8 dg (minimize PRCL to MICH coupling), matrix element REFL9 to SRCL changed from   -0.015 to -0.038 (to minimize PRCL to SRCL coupling)
DARM noise attached, compared to O1 spectrum (with some caveats about calibration). The optical gain and the cavity pole have been slightly changing since the beginning of the lock and we have not compensated for that. SensMon is reporting ~75 Mpc but we believe that in reality the range is a bit lower than that. 

PI report: Terra left us the perfect PI tuning, at least for the first 2 hours of lock, as we didn't have to do any PI intervention.

We leave the interferometer in Observing Mode, Intent bit set at 9.15 UTC, Sept 23.

It will be good to see tomorrow how stable this tuning was, and try to get a clue of how laser noise couplings are changing during lock.

Some minor details: Kiwamu had to fix several things to be able to lock: the main one is that PR2 L2 PITCH was somehow disabled; the ISS second loop was not correctly engaged by the Guardian because of a typo, now fixed -- the lockloss tonight was due to us trying to engage the ISS second loop during power up while realizing it was off. OMC alignment integrators were off (?), we engaged them manually. We also turned off the dither lines before setting the intent bit.

Jenne, Sheila, Lisa

Before the earthquake in Japan brought us out of lock, we tried to engage the ISS boost 1 and 2 (Sep 22, 23:55 UTC) in low noise.
Our jitter/intensity coupling is changing over time, and that makes it difficult to do comparisons, but this time it seemed pretty clear that engaging the boost significantly reduced the noise between 300 Hz and 1 kHz (the bump between 200Hz and 250Hz is an intentional noise injection). 
We haven't been brave enough to do an on/off test, but it seems a good thing to keep the boosts engaged as baseline.Thanks to Jenne, these boosts are now engaged by the Guardian (code not tested yet). 
A couple of other tests:
at 22:58 UTC, I had reduced the CO2X power from 400 mW to 240 mW, close to the optimal value  estimated by Kiwamu yesterday . This is not yet part of the ISC Guardian code as we need more testing (I haven't seen any obvious improvement from that just by watching the noise); 
 starting at 23:42 UTC, I have explored new offsets for the IMC WFS (best offset for DOF1_P found by Sheila yesterday was 170; we clearly needed more during this lock). 

Title:  09/22/2016, Evening Shift 23:00 – 07:00 (16:00 - 00:00) All times in UTC (PT)
State of H1: IFO is locked at NOMINAL_LOW_NOISE and 50.2W. Environmental conditions are good; wind is a Gentle Breeze (8 – 12mph) and seismic activity is low.        
Commissioning: The commissioning team is taking full advantage of a Low_Noise IFO. 
Outgoing Operator: TJ
 
Activity Log: All Times in UTC (PT)

23:00 (16:00) Start of shift
00:26 (17:26) Lockloss – Mag 6.2 EQ near Katsuura, Japan

Title: 09/22/2006, Evening Shift 23:00 – 07:00 (16:00 – 00:00) All times in UTC (PT)
Support:  Kiwamu, Lisa       
Incoming Operator: N/A

Shift Detail Summary: After seismic settled down following EQ in Japan, ran through initial alignment a couple of times. Ran through several relock attempts. Several additional smaller earthquakes in the Western Pacific started to ring back up the seismic bands, although not too badly. Locked the IFO at DC_READOUT and turned back to commissioners.       

According to the TCS measurement we did last night (29901), a good CO2X power to minimize the intensity noise coupling is 240 mW. This should give us an additional factor of 3 suppression.

For the frequency noise coupling, we did not reach an optimum point, but with the240 mW CO2X, it will give us a small supression of 20% or so.

[The test]

• 2016-09-22 6:57, CO2X: 400 mW --> 0
• 2016-09-22 7:40, CO2X: 0 --> 230 mW

See the first attachement or a screenshot of trend below for how things were stable during the measurement.

[Intensity noise couplings]

As seen in the animation below, the transfer function did not change its shape. As the defocus on ITMX compensation plate changed, the overall scaling factor changed.

To show that we passed an optimum point (where the coupling is minimized almost all the frequencies), the following plot is the evolution of the transfer coefficient at 650 Hz.

The minimum point was achieved at t = 24 min. or so where the defocus dropped by about 4 uD from the initial value. According to the recent calibration of the CO2X actuator efficiency (29648), this change corresponds to (-4 uD) / (25 uD/W) = -160 mW. Because the initial CO2X power was 400 mW, the optimum point in terms of the CO2X operating power is 400 - 160 mW = 240 mW.

[Frequency noise coupling]

Here are the same analysis for frequency noise. Similarly to the intensity noise coupling, the shape of the transfer function did not change during the measurement.

Similarly to intensity noise coupling, the frequency noise coupling also decreased. See the plot below.

The coupling monotonically decreased as a function of time. In the end the coupling was lower than the initial value by roughly a factor of two.

Sheila, Keita

The 3rd whitening filter does not switch for AS_C segment 3.  The readbacks look OK. 

TITLE: 09/22 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: Jeff
SHIFT SUMMARY: Maintenance for the first half of the day, then commissioning took full affect and now we are locked in NLN at 60Mpc!
LOG: (see attached)
 

3pm local

CP4 = cryopump #4 at mid Y

John, Chandra

First, this morning we installed type K thermocouples along the exterior of the nitrogen exhaust pipe outside - one ~1 ft the exit of the building, one mid way down, one at the end of the SS exhaust line, and the last inserted inside the plastic flex tube (also the flow meter measures temperature).

We repeated yesterday's CP4 experiment by doubling LLCV (66% open) and allowing CP to overfill beyond 100% until LN2 came out the exhaust. I was physically at the exhaust line during the violent transition taking temp. measurements along exhaust. LN2 sputtered into plastic flex tube, so I quickly opened bypass exhaust valve and closed manual LN2 fill line on main Dewar (temporarily). It didn't help that during this chaos there were reverberations from an airplane or big truck in the distance that sounded like the entire arm coming up to air.

Temp measurements along the exhaust line (degC):

Time      TC1 (wall)     TC2 (mid)     TC3(end)     TC4 (flex tube)     TC5 (flow meter)
14:07     -27.4          5.8           21.9         22.8                -
14:43     -25.2          11.1          25.9         26.1                28.xx
14:55     -27.5          10.1          26.2         26.2                -
15:01*    -57.5          -49.3         -57.6        -193.8              -0.5
15:30     -23.1          13.7          15.6         16.3                19.7

*LN2 out the exhaust

Flow meter seems to be functioning still

John and I are considering installing a TC inside the end of the exhaust pipe at CP3 to use both this signal and the exhaust pressure to develop an automated fill every 2-3 days (no flow meter).

After alleviating the clipping of the PCal beams yesterday (aLog 29873), TJ and I performed the end station calibration today during the spontaneous maintenance day period.  See attached report for full data, but the good news is that the optical efficiency of both PCal beams has returned to 98%.  The previous total optical efficiency for both beams was 62%. 

The diffracted power versus ISS offset slider value was measured.
Attached is the plot for the percent diffracted power versus AOM
drive signal.

Unfortunately the plot isn't really parabolic.  Looking at the plot
it looks like the best region for the AOM drive is somewhere between
0.65 and 0.75 V.  Which represents somewhere between 8.5 and 17%.

A better characterisation of the AOM drive involves adjusting a pot
on the ISS board to better linearise the output of the multiplier
chip.  That's a somewhat iterative process between measuring the
diffracted output and adjusting the pot.

The full power of the laser was measured to be 167.5 W.

Pulled network/power cables from the Vacuum rack to the RGA's at the end stations. This is to connect the RGA's to the vacuum network. Cables still need to be terminated.

We seem to have discovered a new issue with the fast shutter. When the fast shutter is set to the blocked (closed) state by the user and the trigger is enabled for 5 sec or longer, it will open.

In order to combat the weirdness with the diode chiller temperature not reaching its desired set point
of 20 degC, I raised the set point to 21 degC.  This seems to have brought the chiller temperature
to ~19 degC.

    Trending the diode chiller temperature, one can see that there's an oscillation in the actual
temperature.  It might be to fool the system we ought to change the temperature set point to 22 degC.

From the trend data one can easily see the temperature oscillations that are apparent when one looks
at the chiller control panel.

Nutsinee, Kiwamu,

This is a belated log.

In this past Tuesday, we went to the HWS table and checked two things in order to study unexplained behavior seen by HWSY (29738). No major conclusion yet.

• We checked the spatial profile of the launching beam using a Thorlabs beam profiler.
  • We checked the beam up to the bottom periscope mirror. No obvious clipping was found.
• We checked the dependency of the returning beam position on the ITMY and CPY angles.
  • This test was unfinished because we ran out the maintenance period.
  • Nonetheless, according to a quick test, the beam(s) the HWSY camera receives seemed to be made of a reflection from ITMY and other reflection from CPY.
  • To be continued.

By the way, we (re-)found that a green beam coming down to the same HWSY path was clipped at its bottom part.

Lisa, Kiwamu,

We think that the calibration has been wrong and therefore it lifted up the noise floor below 300 Hz. We need another set of eyes tomorrow to doublecheck our theory (we are currently too sleepy to do systematic investigation).

In short, we believe that the sign of ETMY L3 stage in CALCS (or somewhere else similar to it) is wrong which is exactly the same situation as what happened in this past July (28396).

Because I knew that our DARM open loop model is accurate and consistent with the recent measurement (29748), I made a calibration filter for DARM_IN1 which converts DARM_IN1 to DARM displacement as opposed to the use of both DARM_IN1 and DARM_OUT. Here is a comparison of the CALCS spectrum against the spectrum derived from DARM_IN1.

As shown in the plot, the CAL CS spectrum overestimates the noise floor below 300 Hz or so. This is exactly the same behavior as what we have experienced in this past July. In addition, we have noticed that the noise floor of CALCS changed as a function of the DARM control gain which should not happen in the calibration scheme used in CAL CS. Also, when we flipped the sign of the EY L3 stage in CAL CS, the leve of the noise floor became identical to the one derived by DARM_IN1 and also became insensitive to the control gain. This increased our confidence that the L3 sign was wrong in CALCS.

We are leaving the L3 stage gain flipped (DRIVEALIGN_GAIN -30 --> +30) for the night. If our theory is correct, we regain the binary range back to ~60 Mpc with this change.

Also, we took a DARM open loop and PCAL sweep measurement within the same lock stretch. We did not analyze them yet, but they are available at:

/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER10/H1/Measurements/PCAL/2016-09-21_H1_PCAL2DARMTF_4to1200Hz.xml

/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER10/H1/Measurements/DARMOLGTFs/2016-09-21_H1_DARM_OLGTF_4to1200Hz.xml

Also, my code which generated the calibration filter for DARM_IN1, as well as, the generated filter are available at:

/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER10/H1/Scripts/ControlRoomCalib/CalibrateH1DARM_IN1.m

/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/PreER10/H1/Scripts/ControlRoomCalib/DARM_IN1_calib.txt