Since our calibration of the CARM offset in physical units is not very accurate, I post here a couple of plots with powers vs TR_CARM_OFFSET (sqrt(TX + TY) = -TR_CARM_OFFSET). 

The highest power build up we reached so far had TR_CARM_OFFSET = -15 (see first plot, arm power = 115 x single arm, as measured by TR_Y_QPD_B_SUM,  entry 15323 ); in this state the BS correction signal became very large and we unlocked in ~ 1 min. Even if we didn't stay long on the previous state (TR_CARM_OFFSET = -12, arm power = 74 x single arm), we didn't notice any instability there; so I think it is fair to say that TR_CARM_OFFSET = -12 is the highest stable state we reached.

 On Saturday , Stefan left the IFO locked with TR_CARM_OFFSET = -8 (arm power = 32 s single arm, Guardian state TR_QPD_TRANSITION). It stayed locked for about 1.5 h! (second plot). The current last step of the Guardian (which has been failing on Saturday) goes directly from -8 to -15 (corresponding to the state CARM_20PM). 

We will stop around -12 next time. 

Laser is ON
Output power is 33.1 W
Watchdog is active
No warnings other than VB program online

PMC
Locked for ~ 18 hours 41 minutes (!should be days/weeks)
Reflected power is 9.8% of transmitted power

FSS
Locked for ~ 49 minutes (!should be days/weeks)
Trans PD threshold is 0.4V (!should be at least .9V)

ISS
Diffracted power is ~ 8.3%
Last saturation event ~ 18 hours 43 minutes ago (!should be days/weeks)

Here is a summary of the problems we had Sunday

• alog went down 10:45 PST when I was making my entry. It was recovered this morning (please see Ryan's alog entry)
• /ligo file system went down at 11:28 PST, was recovered by rebooting cdsfs0 at 15:00 PST.
• PSL laser went down at 07:23 PST and was recovered at 15:30 PST. Investigation is ongoing.

Here is the list of commissioning task for the next 7-14 days:

1. Reduce common length to zero.
2. Hand-off common mode to to RF.
3. Retune WFS with TCS ITMX central heating on.
4. Lock interferometer on OMC.
5. Search for red resonance sometimes fails.
6. Check RF power on 2f detectors.
7. Keep investigating lock losses.

Alignment team:

1. Make EY green WFS work again.
2. Model changes to include green WFS feedback to TMS.
3. Commission an arm alignment controls topology which can be used for initial alignment.
4. Integrate green WFS into initial alignment.
5. Revise initial alignment scheme.

Miscellaneous:

1. Fine tune Michelson contrast defect using ITMY TCS/CO2 laser.
2. Model changes in SUS for bounce and roll mode damping.
3. Finish cleanup of ISI controllers (BSC2/10).
4. Use HWS to check thermnal lens.
5. Investigate long-term alignment stability of mode cleaner ISS.
6. Add an "ISS engaged" state to the IMC guardian.
7. Implenment updated tidal compensation/length relief strategy.

RF:

1. Make an assessment of RF cross talk into the IMC AOM.
2. Investigate EMI radiation by the VCOs and the fixed frequency OCXO.

We had some stability problems yesterday and overnight - see the plot.

ISS diffracted power was ~ 11% this morning. I adjusted it down to ~7.6%. Refsignal was adjusted from -2.07 to -2.11.

Eric Gustafson here this week to work on optical levers, TCS and 3IFO.

PEM cabling at end Y and corner station.

Possible work on PCAL HW at end X this week.

Quad take down from test stand to be scheduled.

Jeff B. and Andres working on 3IFO storage this morning. There will be craning. LVEA will be transitioned to bifurcated laser hazard.

Corey may work on kitting 3IFO ISC hardware in the squeezer bay.

Possible work on adding seismic sensor correction to HAMs 2 + 5.

Contractor scheduled this morning to fix PSL AC unit that was found knocked over.

Digging continues for trench to warehouse, should be cutting asphalt today.

Temperature excursions at end Y and end X on the order of 1 - 1.25 deg F.

K. Venkateswara

Friday's 50 mph winds produced impressive amounts of ground tilt, especially at ETMY. The attached pdf shows the ASD of 5k seconds of data around the time winds were at their highest in the plot John posted. It shows the outputs of seismometers at EX, Corner station (HAM2 as the representative) and EY all along X direction, and the BRS located at EX. Note that the while the seismometers see both tilt and horizontal acceleration, BRS records only tilt. I've also shown Y direction at EX to check for cross-couplings. Seismometer displacement has been converted to tilt (radians) by multiplying by w^2/g.

Some interesting features:

1. Looking at the data, it is clear that X along EY showed particularly remarkable levels of tilt corresponding to ~100 nrad/rt(Hz) (at 0.1 Hz!) which is at least 1000 times the tilt during quiet times. This was enough to submerge the ~1 micron/rt(Hz) microseism!

2. The wind-induced tilt has a smooth spectral shape in the ~10 mHz to ~few Hz range (as noted by Brian earlier in 602). The dip in the BRS_RY_OUT near 10 mHz is due to an incorrect inversion filter (see 638).

3. Note the crossover in the EY_X spectrum at ~0.5 Hz. The acceleration spectrum seems to go as f^2 above 0.5 Hz (~constant displacement). This suggests that the coupling from wind to seismometer output is through tilt at frequencies below 0.5 Hz and through real displacement above that (again refer to 602). This perhaps suggests an interesting length scale of ~ g/(2pif)^2 ~ 1 m (thickness of the foundation/height of seismometer from point of rotation?).

4. There is good coherence between BRS and EX_X as expected. There is no coherence between BRS and any other sensor indicating that at least wind-induced tilt is very local for each test mass (also expected).

5. The corner station tilt is lower than that at ETMX by factor of 2-3. This was expected due to the much larger mass and size of the corner station foundation slab.

Came in to find the frontend laser watchdog disabled.  Attached a plot of the past 14 days of the watchdog
status.  The plot suggests that it turned off around 7 am Sunday.  Not obvious why.

I enabled the watchdog.

Backups filled up the disk on the aLOG DB server causing the outage from Sunday morning to Monday morning. These have been cleaned up, along with modifications to the backup scripts to purge older backups more aggressively. Log entries from Sunday are missing due to the server being unavailable during this time period.

no restarts reported. Conlog frequently changing channel list attached.

model restarts logged for Sat 29/Nov/2014
2014_11_29 14:44 h1fw0
2014_11_29 23:26 h1fw1

both unexpected restarts. Conlog frequently changing channel reports attached.

Sheila, Elli, Dave, Stefan

We spent some time to automate the transition to a CARM offset of 30ppm.

In particular:
 - The DRMI looks ok with the new TCS settings. We did not retune the loop gains - that should probably still be done.
 - Noticed that with the new TCS central heating on ETMX the WFS loops in DRMI behave differently.
 - We increased the gain of PRM pitch WFS loop by 10 to H1:ASC-PRC1_P_GAIN = -0.06
 - We increased the gain of PRM yaw   WFS loop by 20 to H1:ASC-PRC1_Y_GAIN = 0.02
 - We turned off the SRM WFS loops - they seem to be unstable with the new TCS heating.
 - We moved the transition to RF DARM to a setpoint of sqrt(TR_X+TR_Y)=1 (was 2). This seems more robust.
 - We tweaked the PREP_TR_CARM state to give the Beckhoff servo some time to converge
 - We rewrote the transition to CARM_TR in Guardian - it's now really smooth.
 - We added and commissioned the states RF_DARM, CARM_30pm, TR_QPD_TRANSITION and CARM_20PM. They do what was discussed in alog 15318.
 - The challenge is at the CARM_20PM step - it doesn't want to stay there fore too long...

The only troublesome spot is the ALS_COMM CARM fringe finder. It often grabs the wrong one, and advances to DIFF before the serve setled. Definitely needs work.

The the CARM reduction steps from DRMI_LOCKED to TR_QPD_TRANSITION worked twice in a row flawlessly.

One of the PSL AC units outside the control room/LVEA was pulled out of its anchors and blown over sideways.

Last Wednesday we reset the HEPI length actuator which is used for tidal correction back to zero. The accumulated value at this point was 0.40 mm. The apparent tilt seen by the optical lever was –7.1 µrad in pitch and +5.9 µrad in yaw. However, most of this apparent tilt is due to longitude-to-angle coupling in the optical levers; for ETMX E1200836 lists 20.9 µrad/mm in pitch and 11.9  µrad/mm in yaw. With 0.40 mm we expect to see 8.4 µrad in pitch and 4.8 µrad in yaw.

After resetting the tidal actuator the cavity was locked and realigned. The misalignment was mostly in yaw where we adjusted by -1.6 µrad which is also seen in the optical lever. This was required for both ETMX and TMSX. The pitch alignment was minor with 0.5 µrad for ETMX and nothing for TMSX.

Summarizing, the observed longitude-to-angle coupling is within 15% of what we expect and the ETMX HEPI length-to-yaw coupling is about –4.0 µrad/mm.

The weather has been somewhat violent this weekend. Daniel was asking about the temperatures in the LVEA/VEAs so I attach a recent plot.

Note that the ZONE Average is the LVEA average of ~64 sensors so I also include the worst looking zone, ZONE3B, which is the Y beam manifold area. The most remote sensor of this zone is down by the cryopump near the exit vestibule - this sensor is affected by north winds which leak through the doors. Perhaps an oplev in that region is suffering.

YEND is not as stable as XEND.

Dave O, Stefan, Elli

Yesterday Stefan and Kiwamu  turned on the ITMX CO2 laser was turned on to 440mW and the simple michelson was left locked.  See alog 15328. 

Today we looked at the effect this had on the contrast defect.   When the CO2 laser was turned on, the contrast defect improved untill it was almost zero after about 35 mins.  The contrast defect then got worse as the ITM continued to heat up.  The ITM takes >4hrs to reach thermal equilibrium after the CO2 laser is switch on, as measured in alog 14742.

Using Aidan's measurments from alog 14742, we re-calculated the power needed to minimise the contrast defect to be 255mW.  To do this, we fitted a curve to the time dependent behaviour of the spherical power (see picture).  This fit was

y=aexp(-bx)+c

where

a=-8.14e-5

b=-4.27e-4

c=7.9e-6

We adjusted the ITMX CO2 laser power to 255mW.  The michelson broke lock early this morning possibly due to strong winds.  We were unable to relock the Michleson interfereometer possilbly because of  ongoing strong winds and hence could not see the change in the contrast defect, that is the next step. We have left the CO2 power on at 255mW and so the next time the michelson locks we will have the optimum contrast defect.