Throttling Turbo inlet valve confirms that gas load is coming from the chamber-side -> Connected LD and sprayed helium -> no response -> LD used is one that had been dedicated for view port testing in the labs and has older firmware that I am not familiar with -> can't find external cal-leak to confirm proper operation -> Did get a response however when O-ring joint (NW, KF) was sprayed at completion of testing -> Will leak test tomorrow (Wed) using "normal" equipment 

Summary: Recent CS seismic levels above 10 Hz are about twice iLIGO levels (probably because of HVAC flows), and a few times power-out levels. With power out, the CS has higher vertical motion and lower horizontal motion than the vault, suggesting that Love waves are scattered from the CS slab and reflected from a subsurface layer.  Thus the CS is likely to have different Newtonian noise levels than other stations.

During the power outage in August, I used battery power to obtain a Corner Station seismic spectrum with little self-inflicted noise. Figure 1, the X- and Y-axes, shows that the current level is, between 20 and 70 Hz, about twice the iLIGO level and about 4 times the power-out level. There is more self inflicted noise in the Y-direction than in the X-direction. This is consistent with the location of the broad-band sources, turbulent flows of air and mainly water, associated with the HVAC, roughly in the –Y direction from the seismometer.

Figure 2, the Z-axis, shows that, between 10 and 70 Hz, we are about a factor of 2 worse than iLIGO and a factor of more than 5 above the power-out level. The difference between recent and iLIGO spectra probably indicates that we haven’t yet completely returned HVAC air and water flows to iLIGO levels.

The Corner Station has always had more vertical and less horizontal seismic motion than other buildings (Figure 3). Figure 4 shows that the vertical/horizontal motion ratio at the corner station is considerably greater than one above 10 Hz, while the ratio is near one out away from buildings at the vault and at all other stations. Figure 4 also shows that this difference between locations is not associated with equipment in the LVEA but holds even when the power is out. With the power out, the CS horizontal motion in the 10 to 30 Hz band is slightly less than at the vault and the vertical slightly more (Figures 1 and 2). Assuming that the vault represents the building-free ambient background, it is as if the CS were converting horizontal into vertical motion.

These data are consistent with a hypothesis that the CS slab is large enough to scatter Love waves  (horizontally polarized surface waves), and that the scattered waves increase vertical motion by reflecting off of higher velocity layers tens of meters below the CS. Measured propagation velocities suggest that 15 Hz Love waves would have a wavelength of about 20 m. The outlying stations would mostly fit within circles of 12 m radius, while the corner station requires one with a 50m radius, consistent with a significant scattering difference between stations. If the broad peak at 15 Hz in the power-out trace of Figure 2 represents a resonance between the reflecting layer and the CS slab, than the reflecting layer would be about 15m below the surface. Love waves do not alter density distributions and so do not couple gravitationally. Thus conversion of Love waves into waves that couple, would increase Newtonian noise. This difference between corner and end stations may result in different requirements for an optimal Newtonian feed forward system.

I suspect that the ~250 Hz peak in the LLO DARM spectrum, and, I would guess, soon to appear in LHO’s DARM, is in part due to the piezo actuator/mount connection on the periscope (https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=14971). The last figure in the linked log is a photo of the mount on the LHO periscope. I set up an isolated version of the actuator/UA 200 to test my guess that the frequency is due to oscillation of the piezo actuator in the UA 200 mount. Figure 1 shows that a gentle tap on the actuator produces a large peak near 250 Hz. Figure 2 is a photo that shows the setup and, in the background, a picture of the actual setup on the LHO periscope. I eliminated several possible sources of the resonance, other than the mounting.  To test that it wasn’t the large optic with the piezo “flexure” acting as the spring, I epoxied an iLIGO version of the actuator with a large optic directly onto a plate. The lowest resonance was about 800 Hz. To check that it wasn’t the entire package oscillating on the connection to the table, I added weight to the mount (not the piezo actuator) and did not change the resonant frequency. I also attached the accelerometer directly to the mount. The peak was much larger, as expected.

There are two paths that I have been discussing with Rick and the Florida group. The first path is to design a new mount that holds the actuator at more than one point along its long axis and reduces moment of inertia. And the second path is to move the piezo actuator to the table and put a normal mirror in a UA 200 at the top of the periscope (since the periscope has a broad 150-300 Hz resonance, the piezo/mount resonance is amplified by being on the periscope). I think we should do both.

ISC end station upgrade RCG2.8.7:Rolf, Daniel, Jim, Dave

Rolf released the EXC code fix as RCG tag-2.8.7. The fix was tested yesterday on the DTS using Daniel's new Integrator Filter Module parts (IFM). Today I installed tag-2.8.7 on H1 and set the release/ pointers to refer to it. Daniel performed model cleanup and bug fixing of h1iscex and h1iscey during the morning, building against 2.8.7. We restarted these models several times today, with attendent DAQ restarts. After the final code change and restart, I repointed the release/ pointers back to RCG-2.8.5.

Daniel confirms the new RCG fixes the EXC and TP problems he was seeing with the IFM parts in the ISC end station models. This closes WP #4984

Power Down h1susquadtst: Jim, Dave

I took the h1susquadtst models out of the DAQ and we powered the front end down. Unfortunately this caused DAQ data errors for many front end systems for several minutes (susauxb123, lsc, asc, oaf in the corner station. all models in the mid and end stations). We tried a streamers restart on an end station sus model, which did not do anything. We then powered h1susquadtst back on and all the errors went away. I had forgotten to remove this system from the rtsystab file which may have caused the problem. After removing from both the DAQ and rtsystab, this time we issued a powerdown command and the DAQ problems were not repeated. To complete the power down of the LVEA test racks, all DC power supplies were powered off, as were the network switches. All power cords were removed from the FE computers.

EX Beckhoff h1ecatx1, Tuesday Freeze Up: Daniel, Dave

The EX Beckhoff system froze up at 13:50 PST. A repeat of its periodic Tuesday problems. Daniel restarted the system, but reported an unclean EPICS IOC startup (started too fast). Both conlog and the DAQ EDCU showed problems reconnecting to many h1ecatx1 channels. The problem was resolved after the EPICS gateway h1slow-h1fe was restarted, but even then it took about 10 minutes for conlog and EDCU to complete the reconnection in fits and starts.

Conlog reconfiguration: Dave

Following the ISC code changes, I reconfigured conlog. Later when conlog was not reconnecting to h1ecatx1, I added conlog's own epics channels to conlog to force a reconfiguration to hopefully permit a reconnection (this did not work, the epics gateway restart was the actual fix).

Partial and Modified-but-not-loaded Filter Module Files Loaded onto Front Ends: Jim, Dave

We performed the Tuesday reload of filter module files which had either been partially loaded or modified and not loaded over the course of the past week.

Modified files which were not loaded: ISIBS, SUSPRM, SUSPR3

Partially loaded files: SUSSR2, SUSSR3, SUSITMY, SUSBS, LSC, ASC, ASC-IMC, ISIHAM4, SUSETMX

SVN code with local SVN modifications: Dave

Attached is the list of FE user source code with outstanding local mods in SVN. Also listed, that for the guardian nodes source files.

LVEA: Laser Hazard
Observation Bit: Commissioning  

07:30 Karen – Cleaning in the LVEA
07:50 Cris – Cleaning in the LVEA
08:02 DGR delivering doors to VPW
08:50 Add 225ml water to diode chiller
09:30 Corey – Working in Squeezer Bay
09:35 Dave – Upgrade h1iscex & ey to RCG2.8.7 
09:35 Richard – Going to LVEA roof
10:28 Dave – Restart h1iscex
10:30 Praxair delivery of N2 to CP1
11:19 Kyle – Working on Instrument air in CS
11:42 Dave – Restart h1iscex
11:45 Dave – DAQ restart
12:01 Dave & Jim – Shutting down H2 Test Stand in LVEA
13:02 Richard – Turning on ESD at End-Y
13:34 Richard – Finished at End-Y
13:41 Elli – In LVEA working on IO2TR
14:00 Kyle – BSC9 on turbo pump
14:13 The PLCs at End-X stopped
14:35 Daniel – Restarted the End-X PLCs
14:37 Dave – Restart h1iscey and h1iscex
14:42 Dave – Restarted the DAQ
15:00 Kyle – Going to X-Beam manifold
15:49 Kyle – Going to End-X to check on pump down

Merry Christmas to all and to all a good night! 

X-end turbo also being backed by QDP80 -> Local scroll pump has same issue with its relay module as does the Y-end scroll, i.e. leads not landed on correct relay terminals or relay terminals not matching universal socket labeling etc. -> These two units have different relay components than the functioning YBM and XBM Turbo backing scrolls (why?)

This was running but valved-out for the recent HAM1/GV5/GV7 activities

Kyle, Bubba 
Switch contacts not really open and not really closed, i.e. ambiguous -> Resulted in switching failures past 24 hours or more

Attached is before and after ISI CPS & GS13 Spectra--No real change--Refs are with B STS and current traces are with the A STS.

See attached for the results.  The inline coupling is on the left and crossaxis is in the right plots.  The medms show the matrix elements.

This aLOG details the measurement.

Pretty good results here with ~10x improvement at the lowest frequencies.

Results from PSL weekly health report weeklies are posted below

The following elog is in support of Evan's upcoming elog on last nights TCS transient (turning off TCS)

Bottom line:

The contrast defect (CD) can be modeled as

CD = CD_0 + pi^2/8 * D^2*w^4/lambda^2 

where:
CD    : contrast defect
CD_0  : residual contrast defect, not due to ITM RoC mismatch
D     : Diopter change in (one) ITM, double pass, i.e. D=2*( 1/R_new - 1/R_old )
w     : beam spot radius on the ITM, nominally 53mm
lambda: wave length = 1.064e-6m 

Derivation: 

- incident beam:            |Psi> =  N exp(-r^2/w^2)
- ITMX reflection operator: exp(i*k*D*r^2/2)
- ITMY reflection operator: 1
- reflected field:          |r> = |Psi> * exp(i*k*D*r^2/4) *   cos(k*D*r^2/4)
- dark port field:          |t> = |Psi> * exp(i*k*D*r^2/4) * i sin(k*D*r^2/4)

- Power in dark port due to RoC mismatch:
    = k^2*D^2*w^4/32 = pi^2/8 * D^2*w^4/lambda^2 
  The bottom line formula for contrast defect follows from this.

Some other useful expressions:
- Power reflected from the Michelson:
    = 1 -  = 1 - pi^2/8 * D^2*w^4/lambda^2 
  Note that this power will be in a different mode, so the mode matching into the recycling cavity is expected to change.

And for reference, some Gaussian integrals:
   h_n := 
   h_n = n/4 w^2 h_(n-2)
   h_0 = 1
   h_2 = 1/2 w^2   
   h_4 = 1/2 w^4   
   h_6 = 3/4 w^6   
   h_8 = 3/2 w^8   


 
  

A couple of changes were implemented in the iscex/ey models:

• A new RCG version was installed which fixes the EXC/TP issues we had with the new integrators. This was tested and works fine.
• The PZTs for the input pointing are now using the new integrators as well.
• The PZTs for the input pointing are now triggered on the QPD sums. When not triggered, the integrators are bled off.
• Some old initial alignment stuff has been removed (lock-in oscillators are still there).
• The integrators now have an off-load button. When active with the output and bias on and with the bleed off, setting a new bias value will subtract the difference from the old bias value from the integrator output. This off-loads the integrator into the bias instantaneously without a glitch.
• Fixed a typo in the WFS_SWITCH channel name.
• DAQ channels for the PZTs are now derived from the _DRIVE channels (the _OUT channels are before the bias)
• The medm screens were updated to reflect these changes.

Ran PSL DBB scans this morning. Results are posted below

Elli, Aidan

Elli noticed that ITMX-HWS wasn't getting a return beam even though all in-vacuum optics are nominally aligned (when viewing the OPTICALIGN channels). We traced the problem to the BS which shifted alignment about 7 hours ago. The optical levers saw a sudden shift in alignment.

I've asked Stefan and Elli to look into this.

model restarts logged for Mon 22/Dec/2014
2014_12_22 00:41 h1fw0
2014_12_22 08:39 h1nds1
2014_12_22 22:28 h1fw1

all unexpected restarts. Conlog frequently changing channels list attached.

ITMX CO2 laser back on at 255mV requested power.

Elli, Evan, Thomas, Kiwamu, Stefan

First we made sure we can still run on the 3f diodes with WFS on:
 - After reconnecting REFLAIR_B and removing the beam dump that worked without a hitch - same WFS gains as coded for DRMI.

Next we wanter to check the PRMI - first on SBs:
- We temporarily turned of the WFS and Kiwamu simply kicked out the SRM by misaligning it - the PRMI stayed locked.
- So we simply turned on all WFS with the same gains as DRMI (without the SRCL loops of course). They worked just fine.

Finally we locked the PRMI on the carrier.
- There we had to change the WFS gain for PRC1, PRC2 and MICH. Those 3 loops were then simply closed.
- We had to slightly lower the MICH_P gain, as we were developing an oscillation.
- Kiwamu will post a PRC recycling gain measurement form that data.