(Sheila, Evan, Dan, Kiwamu, Stefan, Alexa)

We were able to lock DRMI + arms off resonance a few times tonight, but the alignment was not great and we would mode hop and lose lock. The guardian is slow to engage the asc wfs, which usually help save the alignment and get the ASAIR build-up high. We need to take a look at our guardian script to get them to engage faster. We did not get a chance to try bringing the offset in and transitioning to TRX+TRY.

The other problem is that DRMI + arms off resonance takes a while to lock (around 20 min), and ALS DIFF is not staying locked for much longer than that. Nic and Sheila worked on a HEPI offloading script (see Nic's alog). However, by the time we got this up and running, ALS DIFF was not locking robustly. For one it seemed we had rung up the bounce mode at 9.8 Hz, which makes locking much more difficult. Another thing we noticed is that the ETMX oplev is glitching.

Of course, as I write this alog, ALS DIFF has been locked for 8 minutes ... unclear what changed.

Nic and Sheila ran Jim's script to run the overnight sensor correction test.

In these two weeks I optimized few times the IMC angular offsets, in order to reduce the coupling of beam jitter to intensity noise. Attached the MATLAB script I used to decide the optimal offsets. It grabs a period of data (of the order of some tens of minutes) and plot some scatter plots of how the band-limited RMS of intensity noise (measured with IM4_TRANS) depends on the IMC angular DOFs. The script parameters are set at the beginning, and the attached one shows the typical values I used.

The typical result is shown in the attached picture. In this case one can see thay intensity noise tends to be samller for positive values of DOF_1_P and negative values of DOF_3_P. My conclusion would be that we need to add an offset of about -20 on DOF_1_P and about 2e-3 to DOF_3_P. I didn't want to interfere with the ongoing locking activities, so I didn't add those offsets now.

We noticed that at least three times tonight, DIFF lost lock because of glitches in the ALS (Y) refl control signals.  The times were 0:18:12 UTC, 1:35:00 UTC, and 1:47:29 UTC, we didn't investigate all of the DIFF lock losses we had tonight so there could have been other examples.  The glitches were both more frequent and larger in the Y arm, but there are also glitches present in the X arm (they are independent glitches in the 2 arms).  We see the glitches even without ALS DIFF and COMM locked, they aren't in the optical levers, the PZT signals, or a number of other things we looked at.  

Evan and I drove down the to Y end to look on a fast scope at the glitches.  By the time we got down there, the glitches had largely stopped.  

07:03 Karen cleaning in LVEA
08:11 Jeff B. and Andres to LVEA west bay
08:23 Jeff B. and Andres back
08:41 Jeff B. and Bubba to LVEA to look at container
08:43 Filiberto and Aaron to end Y to work on PEM
08:52 Cris checking mid and end stations for cleaning
08:56 Jeff B. and Bubba moving storage containers in LVEA (no craning)
08:57 Travis to LVEA teststand to work on suspension
09:21 Keita to end X to work on green WFS
09:32 Jeff B. and Bubba done
09:32 Travis done
10:10 Cris done
10:40 Jeff B. turned on dust monitor 10 (under cleanroom for 3IFO work)
11:02 Gerardo to H2 PSL laser enclosure to work on OFI
11:09 Cris dropping off frocks at end X
11:22 Bubba taking U.S. Linen to mid and end stations (not in VEAs)
11:25 Keita done
12:04 Hugh and Jim W. checking boards at ITMX
12:13 Filiberto and Aaron done (also labeled cables at end X)
12:25 Hugh and Jim W. done
12:25 Gerardo done
13:48 Corey looking for cables in squeezer bay
14:06 Corey done
15:02 Gerardo back to H2 PSL laser enclosure to continue work on OFI

Sheila noted a while ago ITMX was having weird CPS trips. Hugh and I went out during lunch and checked all of the chamber CPS cable connects as best as we could, but we didn't find any loose cables. Some of the the corner 1 cables (over the TCS table) are missing nuts, but the power boards are all secure on all 3 racks, and all cables seem to be well connected otherwise. On Tuesday, we plan on going out with a Genie and look at fixing the missing connectors on corner 1, if possible.

While commissioners were MIA this morning I took the time to try sensor correction at the beam splitter again. Previously, I had found that it pretty much just made stuff worse, at least when I tried HEPI Z. Unfortunately, that still seems to be the case. This time I tried HEPI Z, and ISI X & Y, and in every case it just made things slightly worse. My attached plot shows a comparison between the ISI X for the BS (red) and ETMX (blue). Sensor correction is off  for the dashed traces, on for the solid. ETMX shows our expected improvements, but the BS gives no joy. Also interesting that the BS doesn't seem to be performing as well as the ETMX generally, but the mechanical and controls configurations are quite different. I've talked to Hugh, and the input and output matrices have errors on the BS (not on ETMX), and the STS2 the BS uses is a little wonky, it reads ~2000 cts, while the other cornerstation seismometers are in the hundreds. The STS spectra all  look similar in the .1hz and above region, but they disagree a bit below, see my second plot. When I get a chance, I'll try using a different seismometer, but I'm pretty sure I've gotten positive results at ITMX using the BS seismometer.

In an attempt to improve (?) previous TF data from QUAD 07, today I checked the cabling connections to both chains and added wipes around connectors that were touching the structure/test stand.  I then retook the RO R TF (which showed an unexpected DC offset).  The results showed no improvement and looked identical to the previous round of measurements.

I also swapped an L2 AOSEM that was showing low counts and retook spectra for all stages.

Attached are the spectra for QUAD 07.  L1 and L2 flags are not aligned.

Alexa, Shiela, Nic

We forgot to post this yesterday ...

Our ASC offloading script had offloaded the wfs to the offset of M2_LOCK_P/Y. Once we ran the script, we noticed that we kicked SRM because SRM is under an offloaded hierarchy, whereas PRM is distributed (BS is also offloaded, but we never feedback to MO P, Y so these filters are off). Looking through all of the optics that we feed back to, only PRM is left under distrubted control, so we decided to swtich PRM from distrubted to offloaded. Our length control scheme for PRM is the same for both these configurations, so this transition was smooth.

We also modified the ASC offloading script to offload the wfs to the M2_DITHER offsets. This signal is always on and is not sent to another stage, so should be okay now. 

Removed the following channels:

H1:ALS-C_COMM_VCO_TUNEOFS
H1:ALS-Y_CAM_ITM_PIT_POS
H1:ALS-Y_CAM_ITM_SUM
H1:ALS-Y_CAM_ITM_YAW_POS

These have been added to the exclude list.

Over the last few days of Gabriele's MC WFS work the MC SUS bias sliders were tweeked.  We agreed to save these new slider settings since the WFS offsets are coming in via a different path anyways.  The guardians for MC1, MC2, MC3 are now green again.

Bubba and I have stabilized the LVEA and VEA temperatures.

We still have known mechanical issues which are probably impacting the control loops so we should be able to improve things - especially XEND.

The one degree spike at XEND on the 19th was due to my attempt to outsmart the system.

Motorized variac heater controls are being ordered for the two end stations which should allow for better control and transient behavior.

We may be asking to raise the set point at XEND - so if anyone has thoughts on this please let us know.

Kiwamu, Stefan, Nic, Evan

First, some troubleshooting:

• The ALS DIFF guardian kept blowing the arms out of lock while trying to engage. We changed the ETMX feedback from distributed to offloaded (see LHO#15208), which fixed the problem.
• I think we can get DRMI to acquire lock more frequently by turning the POP18 trigger thresholds up for MICH; right now the guardian values are 1.7 and 0.8 for upper and lower, but I've found that 20.0 and 3.0 seem to give slightly better results. Maybe it's just statistical fluctuation.
• An open question is whether we can soften the ALS lock losses so that the mode cleaner is not kicked out of lock.

After troubleshooting, we were able to get to DRMI3f+arms with a reasonable duty cycle, so we moved on to the problem of the CARM handoff.

Instead of pursuing sqrt(TRX+TRY), we looked at REFL9I. Surprisingly, we found no response in this signal in response to different CARM offsets. We thought this might be due to bad IR alignment into the arms, so we unlocked everything, then locked the Y arm in IR, and adjusted ETMY to maximize the transmitted IR power. This improved the buildup in Y by a factor of 3, but REFL9I continued to be nonresponsive. While locked, we tried some further tweaking of the ETM alignments, with no success. Relevant UTC times: 2014-11-21, from 09:00:00 to 09:30:00.

There has been some concern that there might be excess cps noise in some of the channels. So i looked at 20 minutes of data at 1am sunday night/monday morning.

Looking only above 30Hz where the sensors have hit the noise floor, all of the coarse channels are similar and between 3.5-4.5E-10m/rrtHz about what we expect.

The stage 2 channels show two outliers, ITMX H2 and ITMX V1, maybe BS H2 also but that is close enough so that it could just be at a large offset (we expect the noise floor to go as the gap squared) I'll check that.

  The first thing to do is for me to look at another time, and to check the cables and connections for those sensors

I looked at a second data set calling it "B" (24 hours later)  ST2 ITMX H2 and ST2 ITMX V1 still show excess noise BS H2 is down to 4.5-5E-10m/rtHz which is a little bit noisy, but probably within what we are calling acceptable. I attached the data because Jeff asked to see the ADC noise on the plot

When I say large offset I mean > 10000 counts, so 1200 counts is centered for this discussion 

New  SR3 offset: [452.9, -155.3].

There could be +-120-ish measurement error for YAW due to difficulty in finding the PR2 baffle right edge, so later if somebody gets suspicious about the clipping finer YAW scan of SR3 might be a good idea. This problem is not present for PIT.

New SR2 offset: [2800, 800].

Tolerance is +-100, but the center value strongly depends on the SR3 offset.

Since Doug is not available for finding the SR3 oplev beam with new offset, and since we use SR3 oplev for damping, we reverted SR3 and SR2 back to the original angle.

Tomorrow morning SR3 oplev will be done with Doug.

Plots will be posted later.

Here is a collection of suspicious CPS trips on ITMX.  This is a problem only on this chamber, which has just cropped up in the last few weeks.  It needs to be investigated. 

Ran a first set of TFs for 3IFO-QUAD09. The undamped plots look OK (pitch is a bit off). The damped plots measurements do not match the model between .1 and 20Hz very well, for both the Main and Reaction chains. Will investigate the cause. Plots are attached.  

As Betsy noted in aLOG 14128 the second pitch mode shift is present as for the other 3IFO Quads tested to date. 

All files, plots, and scripts have been commited to SVN.