Attached is a plot with the HAM5 CPS magnitudes from July 18 (at air HEPI locked) and from 6 Sept when we are under vacumm and the HEPI has closed position loops.  The things we believe are SUS resonances are cleaner now and the HEPI structure modes are lowered in frequency and Q. 

The feature just below 6hz is decidedly softer than the one seen on WHAM4--see comparison in the second attached plot.  All these 'HEPI' features are positioned/shaped differently between HAMs 4 & 5.  Maybe this is external mechanical and I should give everything a good hand-on look-see.

~0915 - 0930 hrs. local 

The HAM6 turbo and its scroll backing pump were accidentally de-energized this morning resulting in the maglev turbo "crashing" onto its emergency bearings -> Chris M. was cleaning the floor near where the pumps were plugged in and accidentally tugged/shifted the shared power cord causing it to lose electrical connection -> I was in the LVEA at the time and heard the "characteristic" sound of the non-levitated turbo spinning down from 48,000 rpm on its unlubricated bearings (not unlike a steel garbage can full of rocks rolling down a steep hill) -> I was able to isolate HAM6 while the rotor was still spinning -> Both of the in-series foreline safety valves worked as intended and the scroll pump was isolated upon the loss of AC -> I was able to restart the pumps without difficulty and was able to resume pumping after ~15 total down time -> HAM6's pressure was perturbed with the loss of pumping and saw a pressure rise from 1 x 10-6 torr to 6.5 x 10-6 torr while the pump was isolated  

This is the second "crash" of this turbo due to loss of power.  This first happened years ago and was also the result of a "wiggled" power cord.  Back then the power cord to the pump cart was removable via an unreliable 1/4-turn twist lock connector.  As a result of this first crash the twist lock connector was abandoned in favor of permanently terminating the cord internal to the cart's control box.  

Note to others:  

Are energized PZTs in HAM6 vulnerable to rough vacuum?  If so, are there protection systems?

There are a few features in the ISI TFs around the resonances of HAM5 but not seen on HAM4.  Jeff suggested TFs with the SUS off.  Attached is the result.  The only thing that stands out without deeper study is a small feature at ~1.5hz on V1.

I reran the TFs completed Saturday but with only 1/4 the averages and just between 0.5 & 5hz.  And, Kiwamu turned the SUS damping back on for the last 15 minutes or so.  This should only affect the V3 results.

Sheila, Alexa, Kiwamu

Even though we swapped the oplev laser for BS recently. The BS optical level laser power started showing another power modulation, which resulted in kicks on BS through the damping loops.

For now, we recentered the beam on the QPD to reduce the intensity coupling.

The power modulation looks more like a step which randomly shows up as a function time as shown in the attached screenshot. The modulation depth is roughly 1%. This was actually big enough to cause BS angle agitation which was visible at the dark port digital camera. The coupling seemed bigger in the horizontal direction presumably due to a bigger off-centering in the horizontal direction on the QPD. After the re-center, the coupling seemed to have become lesser, but it is still kicking BS in its angle. This needs to be fixed.

Alexa, Kiwamu ( a report from this past Friday)

We started checking out the REFL WFSs again. The misssion of the day is to engage the DC centering servos and check out the demod phases.

(REFL WFS DC centering servos)

We applied some modifications on the DC centering servo so that the servo basis REFL_A and REFL_B QPD signals. This had been adjusted to be some other basis (alog 9966), but we wanted a simpler basis. The attached is a screenshot of the new centering servo configuration. The input matrices are simple diagonal matrices so that the servo basis is simply REFL_A and REFL_B. In order to actuate on those basis through RM1 and RM2, we did some algebra based on the number reported in the previous alog (alog 9966). After the adjustment, we tuned up the gains to have a few second impulse repose time scale in every servo loop. Also, the sign of the output matrix were chosen such that all the servo gain consistently has negative sign.

(REFL_A_RF9 looked not great)

While we could easily re-adjust the demodulation phases on REFL_B_RF9, we could not perfectly adjut the demod phase on segment 1 of REFL_A_RF9. In addition, segment 4 of REFL_A_RF9 showed no reliable signals. This looked as if a cable was unplugged or something. Indeed the noise floor of segment 4 was lower than everyone else. We need to check REFL_A_RF9 at some point.

We did not check RF45 because we ran out the commissioning time.

   With installation ramping down, Vern will be chairing the morning meeting for the Detector Group. Meetings will be on Monday, Wednesday, and Friday, starting at 08:30.

OpLevs – Need laser safe to continue work on HAM5. 
               Ongoing alignment and problem resolution work at ITMX and ITMY. 
               Glitches with the BS OpLev laser are being looked into.

Seismic – Continuing work on ITMX control loops stability.
                Commissioning on the various HAM HEPIs.
 
Electrical – Pulling cables and power distribution configuration in the LVEA. 
                  Work on the Chiller 3 tripping problem. 
                  Reconnecting Staging Building fire system to the alarm distribution panel in the OSB 
		 

Some features in TF we'd like to confirm are SUS peaks.  Will desist if needed.

model restarts logged for Sun 07/Sep/2014
2014_09_07 12:28 h1fw1

unexpected restart of h1fw1

no restarts reported

The matrices described in 13703 were installed. This caused a noticable improvement in the shape of the QPD alignment OLGs. They are now more clearly a clean 1/f shape.

I also tuned the OMC LSC demod phase and set the gain for a 80Hz UGF. (This was done by opening the LSC loop and sitting on the side of a resonance and tuning the phase until the Q signal was 0)

Nic, Jamie, Lisa

With the QPD alignment engaged, we did a scan of the OMC in ITMY single bounce configuration. Data are being sent to Koji right now for a careful analysis, but our rough estimate is that indeed the matching to the OMC is around 90%, so slightly better than for ITMX, as expected. 

Scan data: Sep 9, 2014 21:10:08 - 21:12:00 UTC

no restarts reported

Alexa, Sheila, Kiwamu, Nic, Jamie, Lisa

After some ITMX ISI work, PRY initial alignment work and more Guardian work, variable finesse technology has been used to bring the PRMI close to the dark fringe. This time the normalization of the error signals is done with POPAIR_A. The success is only in principle because once we arrived at the final step to transition to RF for MICH, an earthquake sadly hit us..the bad timing of this earthquake is unbelievable (#%$#&*&!). 
The positive news is that with this new alignment the recycling gain is somewhat higher than before. We don't have precise measurements because we haven't really locked stably on the dark fringe yet, but we think we had a recycling gain around 10 at some point during the MICH offset reduction sequence when the alignment was good.

Jim's ITMX ISI measurements are about to start, and they will last until tomorrow around lunch time.

We've been having trouble isolating ITMX. The punchline is, I think I need to collect a new with the seismometers in low gain and redo the loops. The rest of this post is summary/posterity/flagellation.

-Last week, Sheila complained about the performance of the ITMX ISI.

-To fix this, I took a new transfer function, but in response to something somebody said somewhere, I used a different configuration than previous rounds. This time I left the T240 and L4C in high gain, where before I had usually run all the seismometers in low gain for the tf. 

-I ran through all the commissioning scripts, load new cart matrices, new blend filters, new damping loops, and new isolation loops. Loading everything went off with no problems.

-Turning on the isolation loops was a different story. When I left on Tuesday, St1 was partially working, I never made it to St2. Kiwamu and Jaime were able to wrestle St1 into a semi functional state (alog 13746).

-I've continued to wrestle with this. JeffK suggested less aggressive loops, which I have spent a lot of time making successively more and more conservative loops. The first two attached images show a representative old and new loop. The old loop (that Sheila complained about originally) is more aggressive: higher UGF, more gain peaking, more aggressive boost, less phase at UGF (14 degrees!). The newer loop seems pretty "easy" in comparison, but it took a lot to turn it on, and it still rings a little.

-Another clue, suggested by BrianL, comes from looking at the damping filters. The third image shows one of the loops from ITMY and ITMX. The ITMX loop has 7X less gain, but otherwise looks the same; phase looks the same. The 7X is suspicious, because that is exactly the difference in the gain between the high and low gain of the L4C. I had noticed earlier that the DAC outputs when the ISI was only damping looked low (i.e. never higher than a count, when I thought a few tens of counts was more normal).

-So, this afternoon, I tried turning up the gain on the St1 damping loops to 7x. The outputs of the DAC increased to what I thought were more normal numbers, and nothing went crazy. I tried turning loops on at this point, and it was still difficult, but eventually we got everything on for St1. Additionally, some of the ringing was alleviated by upping the gain on a few of the loops, so that is how I have left it. St2 is damping only still, but St1 has been running for the last 4-ish hours.

-I looked at the St1 & St2 seismometers, as well as the op-levs to compare these not-so-great loops and the just damped state and it looks like the current arrangement is a little better than just damping. My last 3 images are the op-lev spectra, and the St2 seismometers. Pretty sure the big peak at 30hz is Kyle's pump cart, so a temporary issue.

-I have scripts set to launch the tf at about 1 am. I may come in to work on this some more this weekend, I'll let the appropriate people know if I do.

S. Dwyer, G. Grabeel

Completed the alignment of the HWS on the ISC table and end-Y for TCS. The green laser had some alignment issues after the power outage that a burt restore didn't fix. Sheila and I put the PZTs in the middle of their range of motion and realigned the beam onto the QPDs. After the green beam was aligned with the irises and centered on the QPDs I began aligning the TCS HWS side of the ISC table.

The new layout worked really well and I was quickly able to get a good looking beam on the HWS. Unfortunately there is an issue with an incorrect pinout on the HWS cable so I will not be able to get the camera running just yet.

As reported before, ITMY OL is making a huge fake triangular wave motion of 10 minutes period mainly in YAW (CH1).

We know that the optic itself is not moving because we cannot see this anywhere else, e.g. look at CH7 (AS_C QPD) and CH8 (L2 stage OSEM of ITMY).

We know that this is not the intensity noise. The RIN of OL SUM (CH6) for this 10min thing is about 0.3% pk-pk while each quadrant (CH2-CH5) sees two orders of magnitude larger signal. In addition, the phase of SEG1 and SEG4 are the opposite of SEG2 and SEG3.

It appears that  either the OL laser or the receiver or both are moving in YAW (unless the electronics of all four channels are conspiring together, which is very unlikely).

We could not find any apparent correlation between this fake OL motion and various FMCS and PEM channels. AOS people, please investigate.