The beam tube cleaning was restarted last week, 02/19/2016, with the same Apollo crew that was on site previously. Scott L. and Ed P. 
Beginning at Mid-Y and working towards the corner after getting things set up again, the crew was able to clean 163 meters of tube ending 9.14 meters east of HSW-1-092. This included vacuuming out the support tubes and capping them in those sections.

1540 - 1605 hrs. local -> To and from Y-mid 

Next fill will be Wednesday, Jan. 27th before 4:00 pm

Title: 1/25 Shift 16:00-24:00 UTC (8:00-16:00 PST).  All times in UTC.

State of H1: Locked at DC Readout for Commissioning measurements

Shift Summary: After tweaking up IMs, I was able to get Input_Align to lock long enough to offload the alignments.  Since then we have had several locklosses due to SDF reversions and MC2 saturations.  The IFO has come up quickly and easily after each lockloss.

Incoming operator: Jim

Activity log:

15:45 Chris to X end area for beam tube sealing

16:07 reset ITMx WDs that were tripped upon arrival

17:08 Jeff B to optics lab

17:38 Mitchell to optics lab

17:48 Jeff B out

17:52 Mitchell out

18:05 locked NLN

18:15 lockloss due to SDF reversion

18:30 Joe D to X arm beam tube sealing

19:00 Karen to MY

19:14 Karen done

19:29 lockloss MCS saturation?

20:00 Joe D back

20:06 locked NLN

22:19 lockloss unknown cause

23:15 locked DC readout for Jenne's measurments

23:17 beam tube crew done

23:30 Betsy to optics lab

23:42 Betsy out

23:46 Kyle and John to MY

According to the cross-spectrum technique (alog 25039), L1 has a different characteristic in noises from 40 to 200 Hz. No surprise.

While a H1 spectrum shows somewhat-feature-less 1/f noise with a sharp 60 Hz peak and its harmonics, L1 seems to have extra structures including a few broad bumps in 50-150 Hz. See the attached plot below.

I picked a GPS time of 1131307217 (Nov 11 2015 20:00:00 UTC) for the L1 spectrum. This is a period well before the L1 dropped the inspiral range and seemingly less non-stationary in 10-200 Hz. 

The ASD parameters are the same as those for H1 -- Hanning, 50% overlap, 1 Hz bandwidth for a 12 minutes data chunk. I used the DARM model of the L1 calibration group to calibrate the cross-spectrum. I have not corrected the time-varying parameters (i.e. kappas) for this analysis. I have not subtracted thermal noises.

We have had plenty of things wrong in the IFO since we used bad safe.snaps to restore after the power outage last wensday.  (A2L gains, missing ASC notches, ETMY bias was accidentally flipped, plenty of dark offsets changed, some violin damping was on with the wrong filters engaged ect...)

This morning Jenne, Kiwamu and Evan helped me to clean this up so we are nearly back in the observe state from O1, with only intentional changes like the LSC feedforward and sending MICH to PR2, which we have accepted. 

There are a few things remaining red:

The bias is flipped on ETMY, and the gain in L3 DRIVEALIGN_L2L (which compensates for the bias flip).  It might be that we have messed up the calibration by doing this flip accidentally, but we were planning on doing it soon anyway. 

I've also implemented a version of the scripts from LLO that load down.snaps in SDF when the IFO goes down, and observe.snaps when we reach nominal low noise.  So far we only have saved a few down.snaps, but if we add more and keep them up to date this should be alot easier in the future since we won't need to be locked to see what differences we have.  

Laser Status:
SysStat is good
Front End power is 29.79W (should be around 30 W)
Frontend Watch is GREEN
HPO Watch is RED

PMC:
It has been locked 5.0 days, 1.0 hr 36.0 minutes (should be days/weeks)
Reflected power is 1.822Watts and PowerSum = 23.85Watts.

FSS:
It has been locked for 0.0 days 0.0 h and 3.0 min (should be days/weeks)
TPD[V] = 1.432V (min 0.9V)

ISS:
The diffracted power is around 8.727% (should be 5-9%)
Last saturation event was 0.0 days 0.0 hours and 2.0 minutes ago (should be days/weeks)
 

Other than work permits, the morning meeting consisted primarily of Tuesday maintenance planning.  Items for Tues. maintenance include:

• PSL team looking at optical surfaces of HPO
• Richard working on sync cabling for CPS and status of PI
• Bubba shimming crane rails
• Hugh huddle testing of unused STS2s
• Jeff B dust monitor vacuum system work
• PSL front end diode current increase (time permitting)

Aidan here (next week?) for TCS work

Dave O, Elli, and new student here for HWS work

Peter gave us notice of a 2W NPRO running in the staging building triples lab.  Signage and barriers are up.

The X1 DTS has been restarted with the exception of the frame writer and NDS. The LDAS gateway computer seems reluctant to boot, and is required for the frame writer and NDS.

no restarts reported for both days.

There are small glitches very close to each second boundary in the ETMY drive signal and the ETMY SUS ad SEI rack magnetometers.

In order to investigate the half-Hz combs in DARM (see alog 20790), I took an hour of data and folded it with a four-second period. If there is a repeated glitch at any multiple of this period, it should become far more visible. The result is that in several channels, there are glitches very near the boundary of each GPS second. The peak time of these glitches seems to be about 10 milliseconds after the start of the second. The glitch does not repeat identically every second. There is one shape in the first second, then one with an opposite polarity in the next second.

The first two attached plots are for the SUS and SEI racks, which are shown with a 40-Hz zero-phase lowpass. The SUS has a narrow spike, and the negative spike is larger than the positive one. The SEI signal is more complicated. The ETMY L3 MASTER signal, which is the DARM output to the ESD, is shown with a 10 to 50 Hz bandpass. These glitches are more like sine-Gaussians, but the even and odd seconds still seem to have opposite polarities.

There are more channels with similar glitches. We can make a more thorough investigation, and use more data and more times, to try to track down the origin of these glitches. Hopefully these glitches are responsible for the 0.5 Hz combs such that removing them will improve those.

An electromagnetic shaker on the blue cross beams of the BS chamber produced greater upconversion than was produced by shaking of any other chamber or the PSL table (ITMY wasn’t shaken) (https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=24194). I unsuccessfully tried to reproduce this upconversion using stage 2 ISI injections in X, Y and Z (I did not try RX, RY or RZ). Next I investigated the upconversion by injecting single lines with the EM shaker on the BS cross beams in order to find the most sensitive frequency band. Figure 1 shows the line injections that produced the most upconversion; they are located between 40 and 65 Hz. Lines injected with amplitudes between 1 and 2 orders of magnitude greater than normal produced broad features around the injection frequency and at harmonics, with amplitudes that were several times background in DARM. The next step will be to inject uniform bands in order to estimate the contribution of the 40-65 Hz vibration background to the DARM noise in the 80-200 Hz band. 

I spent some time looking at how we can reduce the DARM residual.

In the attached plot (template lives in evan.hall/Public/Templates/LSC/DarmResReduce_2015-01-23.xml), yellow shows the nominal DARM residual and estimated freerunning displacement.

Blue shows the residual after the addition of a 3 Hz resonant gain. I put this in LSC-DARM FM10, so the freerunning estimate should still be correct. [However, since the DARM filter bank is full, I had to overwrite some other filter. After this test was over, I reverted my changes and placed this RG filter in the LSC-OMC_DC filter bank for safekeeping.]

Red shows the residual after the addition of the 3 Hz resonant gain, as well as a microseism boost, which I put in LSC-OMC_DC. This affects the freerunning estimate, but the amplitude and phase changes at and above 10 Hz are minimal (less than 2 ° of phase change at 10 Hz).

I ran BruCo on one hour of data from last night. The report is available here:

https://ldas-jobs.ligo.caltech.edu/~gabriele.vajente/bruco_1137640217/

At low frequency, SRCL and DHARD_P are the largest contributions. SRCL is still a factor of few below the measured noise, while DHARD is very close around 14 Hz.

There is coherence with magnetometers (still far from the measured noise)

• EY_MAY_EBAY_SEIRACK at many lines below 100 Hz,
• EY_MAG_EBAY_SUSRACK_Z kind of broadband at  high frequency

No significant broadband coherence in the mistery noise region.

Aborting a DTT measurement caused a lockloss - no good, although not a new phenomenon.

Since there are so many SDF diffs, I'm wouldn't put the IFO in Observe anyway, so I'm going to just leave it Down for the night.

We noticed a small bump in DARM at about 360 Hz, coherent with PRCL. We added a 270-430 Hz elliptic band-stop. DARM improved and the coherence is almost gone. We are losing 9 degrees of phase at 50 Hz (PRCL UGF).

The filter is implemented in the SUS filter bank.

Kiwamu, Sudarshan

ISS Outer Loop Servo Board (S1400214) was modified to include a zero at 100 Hz to obtain a better phase margin. This was done by replacing a resistor R74 from 0 Ohm to 154 Ohm (D1300439) and has been documneted in the E-traveler. 

Initial test has been done after the modification and the board will be installed today during the maintenanace period. Further performance test will be done after the installation and with loop closed.

Inner Loop

ISS Inner Loop has  UGF of 22 KHz with a phase margin of about 50 degress. This was measured with variable gain set at 6 dB for the best phase margin. This is the normal operation settings for Inner Loop.

Outer Loop

Outer Loop has a UGF of 1 KHz ( designed for 4 KHz) with a phase margin of  about 30 degrees. The variable gain was set at 40 dB (max available) and an additional gain stage(?) was switched on as well.

Also tried moving the the Inner loop gain to see if it shows any improvement on the outer loop but no luck.

TF Plots are attached.