TITLE: 06/08 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: Cheryl
SHIFT SUMMARY: Getting back into the swing
LOG:
Jeff & Evan did calibration measurements at the start of the shift. Recovery after lockloss was pretty simple, after doing initial alignment, except Jenne checked the soft error points before the soft loops were engaged. The biggest was about .1 and we survived engaging the loops, but it sounds like it maybe necessary to stop and evaluate when re-locking, for now. PI were also more aggravating than before the pump down. It seems like more modes ring up than before, and mode 28 in particular seems sensitive to phase. The usual sign flip didn't work, but a 10 degree bump and patience were enough.

There are SDF diffs that haven't been addressed, as some need more evaluation, LVEA lights are still on and Corey says the last logged VEA sweep was May 2nd, so we're not going to Observe.

Around 2 UTC, I ran A2L.

 It's been otherwise quiet.

I took over the measurement time from Jenne and took the coherence measurements between DARM and Bullseye signals / IMC WFS RF/DC signals just to confirm the situation of the jitter coupling.

Attachment 1 shows the coherence measurement between DARM and the bulleye signals. They show broadband (30~900Hz) coherence as high as 0.5.

Attachment 2 shows the coherence between DARM and the IMC WFS RF signals. They shows high coherence but they look like mechanical peaks. The IMC WFS DC signals (Attachment 3) also shows qualitatively similar features.

[Jenne,Sheila,Corey,Vaishali]

Summary : We are reliably locking to NLN (If I remember correctly  ~62 MPc)

Timelapse  of the locking sequence :

1. Problem :  IFO losing lock at Reduce modulation depth.

Solution : We started tackling the problem by first undoing the offsets on the POP_WFS_A in order to try an help our recycling gain which had tanked from its normal value of about 30 ish to 26. We could only bring this upto 28 by undoing the offsets that Sheila added yesterday (see alog 36686).

• Lost lock here once by clicking on Noise tunings

2. Problem : Jenne then noticed that the spots had moved a rather large amount (~2 cm on the ETMs in Yaw and ~1 cm in Pitch). See attached figure (SpotPos_O1O2) which shows the average spot position on  the ITMs and ETMs for O1 in pink and O2 in green.

Solution : We changed the L2A decoupling coefficients and set them to what they were before the vent by using dither lines frequencies that were in the a2L script. The logic behind doing this was to try and improve the beam pointing into IFO and bring up the PRC Gain (which is now sitting at ~30) .

• Lost lock here once because we used very large steps for moving the spots

Logic/Methodology : This 'reverse a2L'  where we moved PR3 in Pitch and Yaw (separately keeping an eye on the recycling gain and using that as a figure of merit) to affect the spot position on the ITMs and added an offset to CSOFT and DSOFT in combination to move the spot on the ETMs is basically us trying to move the actuation node to the beam spot (a2L moves actuation node to beam spot).  We compared the dither lines showing up in a current calibrated DARM spectra to the an old calibrated DARM spectra reference and slowly changed the L2A decoupling coefficients in both pitch and yaw. All of this process was done in the guardian state PR3 spot move.

3. We reset the POP_WFS_A PIT and YAW again .

4. Problem : SRCL Feedforward filters different than before

Attempted solution : reset all the filters on the SRC Feedforward to what they were at the beginning of O2.

Consequence : This however didn't work too well and we went back the filters that Sheila had chosen in the alog 36686.

5. Jenne has also reset the green initial alignment set points, so hopefully the next initial alignment will come back to the place we left it thus making relocking easier.

Observations/Notes : Locked in NLN at 62 MPc, Jitter noise back, super high frequency noise has gone away i.e. the DARM spectra almost looks like what it used to before the vent.

Warning : If I have forgotten something or said something wrong, Jenne will correct me in comments :)

The following pressures were recorded for the following Dewars:

8514371 = 50 microns
8514372 = 25 microns
8514374 = 225 microns <-- also knows as CP3.
8514375 = 19 microns
8514376 = 25 microns
8514377 = 30 microns
8514379 = 26 microns
8514380 = 27 microns

J. Kissel, E. Goetz

We've gathered the first set of sensing function measurements since the vent and post cleaning of ITMX. Preliminary results indicate a little less detuning, but otherwise the calibration is quite on target. 

Files live in the CalSVN here: 
/ligo/svncommon/CalSVN/aligocalibration/trunk/Runs/O2/H1/Measurements/SensingFunctionTFs
    2017-06-07_H1DARM_OLGTF_4to1200Hz_25min.xml      = 1 / (1 + G)
    2017-06-07_H1_PCAL2DARMTF_4to1200Hz_8min.xml     = C / (1 + G)

    2017-06-07_H1_OMCDCPDSUM_to_DARMIN1.xml          = Converstion from DARM IN1 [ct] to [mA] of current on DCPDs = 2.82925e-7 [ct/mA]

    2017-06-07_H1_PCAL2DARMTF_BB_5to1000Hz_0p25BW_250avgs_5min.xml   = Broadband Injection for checking GDS-CALIB_STRAIN (start time 2017-06-07 23:04:07 UTC, running until 2017-06-07 23:08:27 UTC. )

While we wait for CP4 % full to come back on scale, I transitioned LLCV from manual to PID mode and set the low-end limit to 20% open (so the transfer line can't warm up). Once the level comes on scale and falls below 96%* full set point, the PI will kick in.

CP4 LLCV was at 20% open for about 12 hours yesterday before it came on scale (<100% full). We might see it come back on scale sometime early tomorrow morning.

*92% is the normal set point - we will reset to this tomorrow when we arrive on site

TITLE: 06/07 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Aligning
INCOMING OPERATOR: Jim
SHIFT SUMMARY:

• H1 locking has been robust for all but the ending steps, but Jenne & Vaishali's work today has made it possible for one to conceivably make it all the way to NOMINAL LOW NOISE (NLN).  
• Jenne & Vaishali were working on alignment and A2L from what I gathered.  After running an A2L, H1 was running at ~56Mpc & it has been locked in this near-NLN state for a couple of hours.
• Ended the shift with handing a locked H1 over to Jeff Kissel for the start of some Calibration measurements & he currently still has it.

OPS Observatory Mode:  Yesterday was my first shift in weeks and I took us out of PLANNED ENGINEERING, to PREVENTATIVE MAINTENANCE.  But maybe shouldn't have done that?  It's a toss up.  I'm thinking we should stay in PLANNED ENGINEERING until H1 is back and we are back to OBSERVING post-vent.

CP4 log file DOES NOT exist!

I have started a SenseMonitor instance monitoring the V1 range at LHO. The current V1 range history is available in the dmtviewer by selecting the SenseMonitor_hoft_V1 monitor. I have attached an example plot showing (unimpressive) H1, L1 and V1 ranges.

TITLE: 06/07 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Aligning
OUTGOING OPERATOR: Cheryl
CURRENT ENVIRONMENT:
    Wind: 7mph Gusts, 6mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.15 μm/s
QUICK SUMMARY:

Cheryl had H1 locked at LOWNOISE ASC.  She mentioned violin/bounce/roll modes; I'll take a look at those and also read their alogs from last night.  On the CDS Overview there is an excitation on H1ASC.

• H1 to LOW NOISE ESD ETMY was consistant, but no NLN 
• ROLL and Violins were high

• Initial Alignment went well, and H1 clearly needed it, big changes in BS, and other optics
• locked and sat in DC readout a while (operator distracted by lack of caffeine)
• tested the need to skip certain steps after LOW NOISE ESD, with the expected results
• relocked and ROLL MODE was a big problem, especially in ITMY, and I added +30deg phase and +30 damping (total gain of 50)
• CURRENTLY: back to LOW NOISE ESD and ETMX violins are all at 3+, not sure why, but stopping here to look at them

 

I checked the Vacuum Site Overview MEDM screen and saw the telltale rise in pressure at the Y-mid station that is consistent with a warming 80K cyrogenic pump,  I investigated and found that IP9 had tripped off so I restarted it.  Only one of the two channels restarted.  The other channel is inop.  While on site I overfilled CP4 by opening the LLCV manual bypass valve 1/2 turn.  LN2 was observed at the exhaust outlet in a total of 38 minutes.  

Vaishali, Kiwamu,

We have implemented the calibration coefficients for the bullseye sensor in the front end today. The PIT, YAW and WID signals are now calibrated in fractional amplitudes. They are defined as

(fractional amplitude) = | HOM amplitude (e.g. E_{10} )| / | E_{00} |

Using this calibration, we virtually propagated pointing jitter (a.k.a PIT and YAW) from the bullseye to the IMC WFSs. We were able to get somewhat quantitative agreement with the measured jitter spectra there for the PIT and YAW degrees of freedom.

Next things to do:

• measure/check the IMC WFS calibration.
• measure the pointing jitter coupling transfer functions (again).

[New calibration settings]

Since Vaishali is writing up a document describing the calibration method, we skip the explanation here and just show the results.

• PIT_GAIN = 1.0
• YAW_GAIN = 1.1
• WID_GAIN = 0.54

Once they were set, we then accepted the SDF, although they are NOT monitored.

[Some noise spectra]

Below, the calibrated spectra are shown in the lower right panel.

The jitter level was about 3x10^-5 Hz^-1/2 for PIT, YAW and WID at around 100 Hz. If these fields go through the PMC, their amplitude should be suppressed by a factor of 63 in amplitude (T0900649-v4). So their level should be something like 5x10^-7 Hz^-1/2 when they arrive at the IMC. By the way, for some reason the intensity fluctuation and beam size jitter are positively correlated: as the laser power becomes larger, the beam size becomes larger at the same time.

Here are plots showing the noise projection for the IMC WFS which qualitatively agree with what Daniel has measured in the past using the DBB QPDs instead (31631) -- IMC WFS noise are superposition of acoustic peaks and HPO jitter.

Finally, if one let these jitter fields propagate through the IMC, they should get an attenuation of about 3x10^-3 in their amplitudes. Therefore the amplitudes of the HOMs after the IMC should be roughly 1.5x10^-9 Hz^-1/2. This number is consistent with what Sheila has estimated for pointing jitter at IM4 (34112). However, a funny thing is that, in order to explain a high coherence of 0.1 for pitch when the interferometer is locked in low noise (see for example, blue curves in the first attachment in 34502), the coupling must currently be about 1x10^-11 m / fractional amplitude, which is more than 10 times larger than what Sheila measured back in February (34112). What is going on?