Summary:

RIN of X arm green beam everywhere (input measured by QPD, transmission measured at corner, reflection measured by WFS) is much larger than Y arm for a broad frequency range, the descrepancy peaking at around 10Hz.

Looking at various things, the beam might be clipping somewhere between ISCTEX green Faraday and TMSX M3 (that's the HR/partial for IR/green to split the green main path and green QPD path).

This is not an ultra serious clipping, causing additional 1%-ish pk-pk RIN, but could be an issue for our initial alignment scheme. Needs more investigation.

Details:

First attachment, top panel shows various RIN when the arms are locked with reasonable alignment (ALS-TRX and TRY both more than 0.95).  Thick lines = X, thin ones =Y.

X arm RIN for input (QPD), transmission (ALS TR) and reflection (WFS DC) are all about 2 orders of magnitude larger than Y at 10Hz. The middle panel shows that the QPD signals for X arm shows similar structure, and it's mainly PIT.

On the bottom panel you see that the PIT to NSUM coherence is really high. This means that the structure is not due to some intensity noise from the laser, it's more likely that the PIT clipping is causing the RIN and increasing (or decreasing) PIT signal at the same time.

Perfect coherence between X QPDA and QPDB means that the clipping location is upstream of the QPD sled. High coherence between the QPD RIN and transmission RIN at 10Hz should mean that the clipping is upstream of TMSX M3 where transmission and QPD path are separated.

Back to the middle panel, the reflection RIN (WFS DC) is larger than input and transmission by a factor of 1.5 or so. This should mean that the clipping location cannot be upstream of the green Faraday on ISCTEX.

So the conclusion for now is that it's likely clipping between green Faraday and TMSX M3.

The noise is not stationary, it goes up and down, but it never comes down to the same level as Y arm.

The second plot shows that X arm has been like this for the past 6 months except for two brief periods.

(Note that I needed to set a factor of 0.685 calibration for X WFS DC NSUMs, as the DC value for these was about 1.45, not 1.00. I didn't have to do this to any other RINs.)

LVEA: Laser Hazard
Observation Bit: Commissioning  

07:15 Karen – Cleaning in the LVEA
08:00 Alarm on PY-199 – Notified Bubba & Kyle
08:11 Jim – Running testing on ETM-X, ITM-X, and HAM4
09:15 Kyle & Gerardo – Installing vacuum gauge on HAM1
09:25 Kyle & Gerardo – Out of the LVEA
12:09 Ken M – Going to Mid-X to recover parts
13:04 Filiberto – Working on Test Stand near Y-Arm spool
13:16 Kyle – In LVEA checking the HAM1 vacuum gauge
13:22 Kyle – Out of LVEA
13:40 Filiberto – Out of LVEA
15:17 Bubba – Going to Mid-X to receiving area
 

I have added some blinkies/flashies to the OPS_OVERVIEW medm screen. FSS: When the TPD Voltage drops below .9V a yellow alert blinker will appear under the FSS button. TCSX: A button similar to the one someone added for the Fast Shutter has been added and will turn red if the LASER should lose power. These are just for "heads-up" until something better can be arranged and implemented.

Just for referecne. If you want to decode a SWSTAT value use the following, and replace '#' with the SWSTAT value:

cdsutils sfm decode #

While Stuart and I were looking at SDF and GRD monitoring, we noticed that there were some empty filters that were requested to be on, but were not on.  I've turned them off.  Attached are the 2 screens where I found such benign filters in the half-state (ETMX L3 LOCK, and BS M2 COIL).  They are off now.  We intend to get new safe.snaps tomorrow so likely any remaining leftover empty filtering will be cleared out.

[Doug C, Jason O, Stuart A]

We are planning a B&K hammer training session on an OpLev pier during the maintenance period tomorrow. I conducted a survey of current OpLev power spectra to help identify any particular piers that we should target. The power spectra (attached below) suggest some very low resonances (3.3 Hz & 6.6 Hz) for ITMY, so we shall focus our attention there. n.b.PR3 looks to be misaligned.

Here are the trends for the past 10 days:

Seismic – Jim running tests on ETM-X, ITM-X, and HAM4 for Jeff K. 
Working on feed forward on HAM4

Suspensions – Stuart is rebuilding suspension models
Installed switchable Mid-Stage coil 
Cleaning up old/unused channels 

PSL – Realigned the RefCav to bring power up to 1.5V. Tightened loose periscope mirror mounts. These could be the source of the alignment drift.  

3IFO – Jodi and team parts hunting in the LVEA. 
They moved the IO parts top the staging building.  
The remaining three desiccant cabinets were moved to the VPW	
Danny checked optics for first contact
The Seismic team moved the last BSC-ISI into its storage container

FAC/VAC – Roughing on HAM1. 
Kyle needs to install a temporary gauge onto of HAM1
SnoValley – On site working on A/C at VPW and chiller yard
OpLev – Modifying grout forms. Hope to start grouting OpLev piers next week 

As a follow on from my alog last week (16811), I ran TFs on the PR2 while the largish IFO pointing offsets were enabled.  With offsets of P = 1816, Y = 4315, the P and Y TFs look healthy.  Phew.

With some guidance from T. Abbott, I have gotten the SUS Drift Monitor back up and functioning.  I have updated all the suspension alignments to the most recent good lock stretch of 1108702216 GPS.  After this update, a few suspensions were showing that they are misaligned from this previously good alignment. 

PR3 - Pitch, not sure why this is aligned differently now.  Trends show this changed Feb. 24 at 20:00 UTC.  I could not find an aLog specifically stating that this SUS was touched.

SR2 - Changed Pit alignment to alleviate possible rubbing.  See aLog 16831.

RM, IM, and OM alarm level are still in a state of flux.  To be continued.

No significant changes from last week.

The version of root software used on x1work has been updated to root-5.34.21, the version of gds software for x1work has been updated to gds-2.16.12.4, to match what is used in the LHO control room.

The daqd and nds software for x1dc0, x1nds1, and x1fw1 has been updated to branch 2-9, r3965.  It was fairly old, at r3626 and needed to be updated to test daqd protocol 12.1 with nds2 client software.

Since we started running feedforward on the BSC-ISI's, Jeff and Hugh noticed that the feedforward path is not controlled by Guardian. This means that if FF is engaged and the ready state is requested through Guardian, the St1 actuators will still be driving. From a safety standpoint, it looks like this probably isn't an issue. I took spectra this morning with the ITMX ISI off (FF off, too) and with FF only (no damping or isolation loops). The FF only state actually still provides some isolation above 1hz (see attached plot, dashed references are the off state, solid lines are FF only). I also turned HEPI off, then turned it back on while watching the ISI seismometers, and didn't see anything obviously terrible. The actuator signals stayed below a couple hundred counts the whole time, much like the ISI with damping only, and only the T240's got agitated while HEPI servoed to position, which is normal. It's still possible that whacking the HEPI piers could cause FF to do bad things, so...don't do that.

See JeffK's 16857 where he analyses the End Station's performance relative to the fluid pressure noise.  The attached plots compare those final performance numbers for YEND  from Sunday at 6pm pst with data taken 25 Feb at 0230utc -- after the EndY HEPI plumbing system maintenance detailed in 16899.

Bottom line--The DOFs still showing coherence on Sunday (Jeff's 16857) are all almost completely gone, there is still a bit of coherence in the HP dof in places between 10 & 100mhz.  So this maintenance would appear to be very important.  The DOFs remaining were the 'common' mode dofs.  That is, the Z and the HP modes of the HEPI--those dofs where the Actuators move in common.  All other dofs have counter moving actuators which one might expect a common noise like pump pressure to cancel out.

Now, understand, Jeff's work on the controller characterization and tuning provided most of the decoupling to the platform; this maintenance work just closed a few final loose ends.

The xml for these is /ligo/svncommon/SeiSVN/seismic/HEPI/H1/Common/2015-02-25_H1HPI_EndYStation_Coh_wISIT240s.xml

I spent some time tonight attempting to adapt the guardian codes to the new LSC and OMC models (alog 16893, alog 16904 ). I went through most of the guarduans by actually running them with the interferometer and tried fixing as many bugs as possible. Here is a summary of the guardian situation (red=bad, blue=OK):

• ISC_LOCK
  • I was not able to get a chance to test this at all. The modifications were already applied and the code itself is ready for testing.
• ISC_DOF
  • I tested the most of it, but I did not explore the non-daily routines such as PR3_ALIGNED and CORNER_WFS_CENTERING paths.
• ISC_CONFIGS
  • I tested it, exclusing the degrees of freedom which are not usually a part of the initial alignment sequence.
• ALS_COMM
  • Tested. I was able to get IR_FOUND without an issue.
• ALS_DIFF
  • Tested. I was able to get IR_FOUND without an issue.
• ISC_DRMI
  • Tested. I could lock on DRMI_1F_OFFLOADED. Did not try further.
• IMC_LOCK
  • Tested. It is locking.

In addition, a couple of associated parameter files (e.g. ISC_library, pdstep and etc.) were also edited for the same reason. Even though I could test most of the necessary parts, one should still pay attention to the codes as it is very likely that I have missed some bugs in there.

(For the ISC experts)

I have several items to mention.

• The channel which used to be called 'LSC-CARM' is moved to a new filter, 'LSC-MCL'.  I moved the old 'LSC-CARM' filters to this new place. The common mode action happens in this filter and not in CARM any more.
• 'LSC-CARM' is now meant to be fed back to ETMs, not MCL.
• The channel which used to be called 'LSC-MC' is now called 'IMC-MCL'. This degree of freedom represents the MC length only for the IMC lock.
• The following filters needed to be copied over from LSC to OMC because they now live in the h1omc model.

• • ASAIR_A_RF45_I
  • ASAIR_A_RF45Q
  • ALS_DIFF_PLL_CTRL
  • LSC_DARM
• In order to reduce careless mistakes in relocating the LSC input and output matrices, I started using Jamie's matrix dictionary (alog 16877). All the dictionaries I newly implemented reside in ISC_library.

Looking at some of the LSC demodulated signals, I found that the RF phases changed by some noticable amount. I then found that the CO2 laser on ITMX had been tripped at 13:51 local (or 21:51 UTC) today. I went to the rack at the floor and saw that a red indicator for 'TEMP' was on at the front panel. Power cycling the unit with the key untripped it. I pressed the red button for opening the gate and confirmed that the laser power was back to the nominal of 210-ish mW in the medm screen. The attached is a one day trend of the laser power, calibrated into the power at ITMX.

I did not do any deep investigations at this point.

Kyle, Gerardo 

Added remaining bolts to HAM1 West door and finished torquing -> Soft-closed GV5 and GV7 (GV5 hard-closed on its own at only 20 psi) -> Pumped HAM1 with scroll pump via vent/purge valve (as such, atmospheric pressure remains on air-side of closed vent/purge valve) -> Opened GV5 and GV7 

Richard M. is investigating getting signal cables to HAM1 gauges