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.

[Sudarshan, Gabriele]

Following up on yesterday's activity, today we properly dumped the beams on IOT2R. We tried different configurations: beam dump directly in place of the first mirror of the periscope, razor beam dumps, black glass plate, black galss beam dump. Finally, the best configuration is the one that lets the beams go through the periscope (recentering all three mirrors) and dump the REFL beam far away with a  black glass angled beam dump, and the IMC trans beam with a razor blade dump. See the attached pictures for more details.

With this configuration, we measured the out-of-loop intensity noise with MC2_TRANS, as before with the PRM aligned and the BS misaligned to avoid flashes. After many trials, we could geth the 18 Hz peak down by a factor 10, as shown in the 5th figure. Green is PRM aligned, ISS second loop off, before our modification. Brown is PRM aligned, ISS second loop on, before our modification. Red same as the last one, but aftr the modification.

The IMC transmission beam is not critical, and even leaving it undamped doesn't change much. Instead, the dumping of the REFL beam is critical. By simply tilting the beam dump of a very small angle (order of one degree), we could change significantly the amount of intensity noise. We tried many times to tweak the angle. Once we could make the 18 Hz completely disappear, but then just the action of clamping down the beam dump wornsed the situation. We think it's not really worth to spend more time on this, since a small change of the PRM alignment will in any case move the beam and probably spoil the noise reduction. The last figure shows a comparison of the intensity noise with different beam dump positions. Blue is before the modification, the other traces correspond to sligthly different beam dump positions. We also tried to rotate the beam dump 90 degrees, to have the black glass plates oriented "horizontally', but this didn't help either.

In conclusion, now the situation is much better than before, but the REFL beam transmitted by IM4 and collected on IOT2R is very critical. We should consider a better solution for the long term. For future reference, the last picture shows which beam we are talking about: the purple beam is the REFL beam transmitted through IM4 and sent otto IOT2R where it is reflected/scattered back to IM4, then reflected off the IM4 HR face and finally going to the ISS aray (green beam)

These are the results of the ETMX excitations to test for working channels. Again, 4hz/10cts/pitch

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.

(Stefan Evan Kiwamu Nic)

We found the ETMX suspension was changed back to distributed control on Tuesday Nov 18, 2014 at 19:14. There was no elog documenting this. We expect this was an error (or maybe a BURT restore?). It's very surprising that we were still able to do ALS control at all in the interim.

The ETMs had been distributed for a long while, but were changed to offloaded while diagnosing ALS DIFF issues.

We've now changed it back to offloaded.

Nic ran Jim's script. 

Earlier tonight, we had a large drift in ETMX pitch (1 urad over about 7 minutes).  I turned off the sensor correction (ETMX ISI X only) for the last several hours, this seemed to help.  Now I've turned it back on so we can see if this continues to happen overnight.  

We are leaving the arms locked in green, and the mode cleaner locked.  This should give a chance to see if the mode cleaner is really stable when there is no actuation on it.  

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 

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.