Checked and set all LVEA Supply Accumulators to 70psi; Return Accumulators set to 20-30psi.

Issues found at H(am)5R(eturn), H6S(upply), H5S, H4S, B(SC)3E(ast)S,B3W(est)S,B3WR,B2N(orth)S(unable to charge due to interference), B2NR, B1NS, B1SR, H3S, H1S, H1R, H2R.

Wow, maybe easier to list the ones that did not need some gas.  Most of the Supply units that needed charging where at 20psi or below. This should make a good improvement in pump pressure fluctuation coupling into to platform motion.  I expect next check should see a much shorter list.

Found that someone had decided to store unused 2" Angle Cable Tray Support Assemblies under BSC1.  Sliding these in, the Feet on the Assembly was just the right height to hit the valve knob and turn it.  Fortunately, the drain exit is capped and no leak occurred.  Please mind the caution tape and be aware of the pushing and pulling things in and around the low dark places where HEPI resides.

Noticed that the Vacuum Pipe, Instrument Air Piping and Conduit are all contacting the SR3 OpLev Transmitter Pier near its base.  This is just East of HAM4 on the North Side.

Reset the watchdog counters for HAM2, HAM3, HAM5, ITMX, and ITMY

I got a chance to test the modified blend filter that JeffK and I came up with on Friday(alog 17256). It looks like it most does what we expected. Attached plots show X, Y and Z dofs for both stages., dashed lines are the before, solid lines are after, red is St1, blue is St2. I don't show it, but there was no change in performance below 1 hz.  I think we might be able to push the elliptical filter down a little more, get some improvements closer to 5hz, but that will have to wait while I run down other projects.

I've installed this on ETMY, ITMY and ITMX, but it's only running on the Y arm chambers, for now.

A side note, the blend filter banks for the BSC's are getting a little weedy. It's probably getting to be time to do a little clean up and make things more consistent between chambers.

Dan, Kiwamu,

At one point last night, we noticed that a roll mode rang up at ~14 Hz. The peak height in the DARM spectrum (ffted with a 0.1 Hz BW) exhibited a anomalously high value of more than 10^-12 m/sqrt Hz.

So we worked on damping the peak, this time with the AS_WFS_A_45Q signal (alog 16864) which is a state-of-the-art Livingston technique. We were successfully able to damp the mode to an ordinary height of about 10^-14 m/sqrt Hz level in the DARM spectrum.

(Identification process)

First of all, see how terrible the roll mode was:

The red curve is from Mar-17-2015 8:51:00 UTC and we were intentionally stayed on the rf DARM rather than the DC readout to combat the roll mode. Even though there was some confusion in identifying which suspension had been rang up, eventually we confirmed that the roll mode was from ITMX by taking coherence between AS_WFS_A_45Q and the OPLEV_PIT signal of each test mass. In fact, the ITMX oplev was able to see the roll mode in its spectrum with a peak ~ 10 times higher than the noise floor while the rest of the oplevs did not see a visible peak.

In addition, after the successful damping on ITMX, the AS_WFS_A still showed a bit high peak but with a slightly lower frequency (~ 200 mHz ) than that of ITMX. We then identified that this was in turn from ETMY by looking at the coherence again. This lead us to another damping work on ETMY which we were also able to damp.

(Damping setup)

The AS WFS_A signal was routed from the ASC model with a gain of +1 (in ASC_OUTMATRIX_TESTMASS_DAMP). I found that both were damped well with a positive gain in SUS-E(I)TMX(Y)_M0_DAMP_R.

As for ITMX, I ended up with FM3 (-100 dB), FM4 (bp13.9) and a gain of +40. Although I had to start from a gain of +1 in order not to saturate the DAC due ot the high amplitude in the roll mode. Then I gradually increased the gain as the DAC counts reduced. Once I went to a gain of more than 10, the mode was damped relatively quickly probably on a time scale of about a couple of minutes.

As for ETMY, I ended up with FM4 (bp13.9) and a gain of +0.0008. At one point I went to a gain of +0.005, but this actually started increasing the peak height. So I had to set the gain back to + 0.0008. This loop could damp out the mode on a time scale of a couple minutes as well.

(Why they rang up ?)

We don't know.  One observation is that before the modes rang up, Sheila was trying to increase the recycling gain by manually touching the ITMs.

Seismic:
	Hugh doing HEPI maintenance in corner station
	Jim performance testing on ETMX, & Filter work on ETMY
	Reboot of End-X BRS computer

3IFO:
	Jodi moving and labeling 3IFO items in the LVEA
	Bubba hooking up 3IFO Quad LS and BS storage boxes to N2 system
	Corey moving bins in and out of the LVEA

PSL:
	Work on RefCav alignment & TFs on FSS

CDS:
	Model and DAQ restarts
	Jim moving the NTP server

VAC/FMP:
	Swapping ion pumps at HAM1 & HAM2
	Tumble weed bailing 
	Hanford FD on site testing fire alarms

Dan, Kiwamu, Sheila

Today we made several gaurdian changes:

• LSC_CONFIGS is now called ALIGN_IFO, and many states that were not necessary for inital alingment are gone.  I've moved the PRMI stuff to another file called PRMI.py, although this isn't a working guardian at the moment. The plan is to eventually merge ISC_DOF and LSC_CONFIGS
• We are now engaging all the DRMI ASC loops within a few seconds, and we are offloading it durring each lock (in the state TR_CARM).  It seems like this offloading has helped reduce our time to relock DRMI.  
• The CARM offset reduction is faster by about 40 seconds than it was. 
• We are now engaging ETM violin mode damping and ITMX bounce mode damping in addition to the ETMY bounce mode damping we had previously included for each lock.  
• THE ALS VCOs are now parked each lock, in the state BOUNCE_VIOLIN_DAMPING

I looked for a signal from the QPDs which was insensitive to TMS angle.  For the X arm pitch I used TRX A - 0.5 TRB and for Y arm pitch 1TRY_A-0.65 TRY_B seemed good.  I closed a verry low bandwidth loop to ITMX using this signal, screen shot is attached.  

We found that we could increase the recycling gain from ~27 to ~33 by moving the ITMs with ASC lops closed on IM4, PR2, BS, common ETMs, and differential ETMs.  We had to move ITMX by as much as 5 urad to do this, and we found that we would loose the lock soon after getting a good recycling gain.  Kiwamu calcualted that by moving ITMX 5 urad, we are moving the spot on the test masses by 1 cm assuming that the ETM is controlled. This may be due to a problem with the DHARD loop. 

We also spent some time looking for a Transmon QPD signal that would be insensitive to motion of the transmon.  We closed a loop to ITMX pitch using TRX_A - 0.5 TRX_B, the attached screenshot shows the settings.  This loop was verry low bandwidth.  

We had a second incident of a permanently ramping slider today, earlier we saw this with SR2 Yaw and just now (3:56:20 UTC) we saw it again with SR2 pitch.  The offset had ramped to the correct value (probably in the 10 second ramp time), but the ramping indicator stayed on.  This wouldn't be a problem except that we are using .is_ramping in the guardians, and they get confused by this situation. 

Again I changed the ramp time, and Dan moved the slider one click and moved it back again, and the ramping indicator went off. 

Dave investigated this earlier in the day when we saw it with yaw.

Scott L. Ed P. Chris S.

The crew relocated lights and equipment this morning. We will be starting at the single door between X-1-5 and X-1-6 double doors and working toward the Mid station. We started vacuuming beam tube supports this afternoon and took dirty samples on the tube. Results posted on this entry. These are some of the dirtiest areas we have seen so far.
A new generator was purchased Friday, however it still needs to be shipped here. A rental generator was picked up this morning to get us by until the new unit arrives. 

This is a reminder that the RF phase of the REFL_A_RF9 and REFLAIR_A_RF9 signals should always be adjusted using the delay line phase shifter. The analog phase shift is applied to the LO signal and therefore effects both analog and digital feedback paths. On the other hand, the phase rotation in the real-time system only changes the digital path. It should always be set to 0°, if the error signal of the REFL servo uses the I output of the demodulator, and to ±90°, if it uses the Q output. One other caveat is that the delay line phase shifter may be in local mode, meaning one has to use the physical toggle switches at the chassis. In local mode the digital settings are getting completely ignored and there is no readback.

Jamie, Dave, Jim:

Jamie reported that the location of the MEDM Print selection, being at the top of the right-mouse pull-down menu, has resulted in many accidental printer jobs. This explains the printouts of things like the sitemap screen with no data content and no one picking the print-outs up.

Jim modified the LHO CDS MEDM this afternoon to move the print section from the top to second from the bottom of the pull down menu. Please see the attached before and after images.

During tomorrow's maintenance we will stop all old MEDMs in the control room so the new feature will be picked up. This is only a linux change, it was not applied to Mac OS.

LVEA: Laser Hazard
Observation Bit: Commissioning   

07:00 Karen & Cris – Cleaning in the LVEA
07:45 Bubba – Chiller delivery from LLO, Bubba unloading truck at Mid-X
08:15 HFD – On site with Richard at Mid-X
08:25 Adjust ISS diffracted power from 5.5% to 8.2% 
08:43 Corey – Going into Squeezer bay for 3IFO work
08:50 Filiberto – IN LVEA making a survey of racks
09:00 Corey – Out of squeezer bay
10:00 Corey – Going into squeezer bay for 3IFO work
10:10 Bubba – Finished unloading truck at Mid-X – Big Red has been parked
10:30 Corey – Out of squeezer bay
11:15 Ken – Working on CER
12:47 HFD on site for fire alarm maintenance
14:20 Richard – Going to Mid-X
14:35 HFD finished testing the OSB fire alarms

Even though the threshold is set to 32k, the Stage2 tripped when the Actuators only hit 30k.  Is this just from the 512k downsampled data?

The attached trend plots shows the full data and although it gets close, it doesn't appear to reach the threshold.  Shame we get shut down for such a short transient.

These are the 24 hour OpLev trends. Will look into the drops in PR3 and the BS.

PSL Status: 
SysStat: All Green, except VB program offline 
Output power: 31.9w  
Frontend Watch: Green
HPO Watch: Red

PMC:
Locked: 13 days, 2 hours, 34 minutes
Reflected power:    2.1w
Transmitted power: 22.5w 
Total Power:       24.6w 

ISS:
Diffracted power: 9.2%
Last saturation event: 0 days, 0 hours, 28 minutes 

FSS:
Locked: 0 days, 0 hours, 5 minutes
Trans PD: 1.347v
 

See the attached for trends of the BRS for health assessment.  It has been down since ~22 Feb.

The first plot is the minute trend of H1:ISI-GND_BRS_ETMX_RY_INMON.  This is 100 days of just the mean and the flat lined sections are BRS in trouble areas.  The 2nd attachment is a 60 minute second trend.  This shows the healthy 9mhz signal of the BRS.

More details on the scattering Dan mentioned on Friday, with some new and re-interpreted details (the responsible motion is horizontal) that became clear after further investigation.

This last Monday, DARM spectra showed a double scattering shelf occasionally reaching 60 Hz and 120 Hz (Figure 1) and even higher.  I searched for the source of the scattering path length variation by looking for motion sensors that detected maximum motion at the times that the higher frequency scattering shelf reached its highest frequency.  The top trace of Figure 2 is a 700s time series of DARM, band passed between 90 and 145 Hz. Each of the spikes in the time series was produced when the scattering shelf reached into this band. The lower plot shows that the maxima in one of the OMC OSEM signals coincides with the spikes in the DARM plot above it. All OMC OSEMs show this correlation except the side sensor (on the short side). I found no other GS13 or OSEM channels that showed this correlation; most importantly, it was not in the GS13 signals from HAM6. Figure 3 is a zoom in to one of the clusters of scattering spikes, showing that the scattering spikes appear to occur at the steepest part of the OSEM signals (when velocity would be highest), and that the time spacing between DARM spikes agreed with the resonant frequencies of the OMCS. Beating between 2 of the suspension modes seems to cause the variation in motion.

Using the 1 um/count calibration of the OSEM OUT channels, I obtained average velocity spetra that, for some OSEMs, reached 10 um/s (Figure 4).

In order to produce a shelf out to 60 Hz, the rate of path length change for a single bounce would have to reach about 30 um/s. The OSEMs measure displacement of the top mass, M1, and the OMC hangs below it. At the resonant frequencies of this suspension, the motion of the OMC, while damped, would still be greater than the top mass. Also, the 10 um/s figure is only an average rms. Thus the OMC motion can account for the 60Hz shelf with a single reflection. 

There are two shelves in Figure 1 spaced by a factor of 2 in frequency. The spectrogram in Figure 5 shows that the frequency spacing of the two shelves is always a factor of 2. The shelf at 120 Hz in figure 1 is about an order of magnitude below the shelf at 60 Hz. If this represents a scattered beam that reflects twice instead of once, then the reflectivities at each of the two extra surfaces would have to be very high. While there may be other mechanisms to generate the double shelf, it is probably worth looking for bright beam spots on highly reflective surfaces in HAM6.

Finally, it would be nice to reduce the motion of the OMC by a factor of ten, particularly, the side to side and rolling motion perpendicular to and about the line connecting the two suspension points of M1, motion detected by the LF, RT, T2 and T3 OSEMs.