Swapped the M4 terminal EL3104 with a spare in the corner 4 chassis. This fixes the problem seen in alog 13364.

Verbal approvals from Mike L., John W. and Andres R. as I was unable to access eform -> I will replace PT180B, PT120B and PT170B tomorrow while John and others re-clock the HAM5/6 septum viewport.  

NOTE: I tested the three new CC gauges that will be installed on an aux. cart and using PT114B's cable.

Negative 18V Power was damaged upon restoring power.  Chassis with no power switches were temporarily powered with only positive 18V.  No damage to the chassis was observed.  Damaged power supply S1300278 was switched with a spare located at EY.  Everything appears to be functioning now.

12:00 – Power is back On. CDs recovery process ongoing
13:25 - Fire Department on site (Maintenance) 
13:45 - Heading to End X to power-cycling electronics- Filiberto
13:45 - Heading to End Y to power-cycling electronics- Aaron
13:48 – 15:35 Going into the LVEA (B-K Hammering) – Tim/Jeff K.
14:03 - Transitioning the LVEA to Laser SAFE – Richard
16:00- CDs recovery process continues ... 

Richard, Cyrus, Jim, Patrick, Kyle, Dave.

The site was without power between the times of 08:32 and 09:05 PDT.

We have recovered the vacuum controls systems. h0vemr, h0vemx and h0vemy rode through the outage and needed no recovery. h0velx, h0vely, h0veex and h0veey required a reset button press, reboot, code start and burt restore (from 23:00 8/13) because they lost power. Robert reports the LVEA VME lost power only seconds before the power came back.

Reracking of MSR is ongoing.

We took the opportinity to perform an fsck on cdsfs0's /ligo file system as this was showing errors.

The clone of h1boot's boot-disk is ongoing. workstations and front end restarts will occur after the clone is completed.

The aLOG will go down soon for the power outage.

Came in earlier than normal to place systems in safe state as is done before planned power outages.  Luckily had help and most of the systems were taken care of last night.  Assistance is appreciated.  

Cyrus, Jim, Jeff, Dave

late afternoon, early evening today we powered down several CDS systems in preparation for tomorrow's power outage.

First systems to be powered down were backup servers and DMT. At 18:00 we started powering down the front end systems, leaving EY until last to allow ongoing commissioning work. By 19:00 all front ends were powered down except h1psl0. We initially stopped all the PSL models, but were unsure if we should leave the PSL overnight in this state. We therefore restarted the models, which closed the shutter in the diode room. We left the PSL in this shuttered state.

I ran the "make installWorld" to install the 2.8.5 front end code into the target areas, when the frontends are powered up tomorrow they will have the new version. I moved the 2.8.5 version of H1.ipc into position.

We powered down the DTS system in the H2 building.

Most control room workstations (leaving the vacuum monitoring machines), all wall mounted mac-minis, TVs and projector were powered off.

The only channels for indoor relative humidity that are inside the CS VEA are the ones inside the H1 PSL enclosure(A.K.A. "Lighthouse dust monitors").

See attached plot for today's RH.

Jeff K., Krishna V.

The data from Tuesday (August 12) night looks very encouraging. The tiltmeter was in vacuum (but not being pumped, so P my be ~ mtorr) and the box was closed. The first plot shows the tiltmeter data (high passed at 10 mHz) over 40k seconds starting from ~9 PM. I've divided by the transfer function to take out the resonance. Note that the vacuum vessel is still not wrapped in foam and doing so along with turning on the ion pump should improve the low frequency noise.

The next plot shows the ASD of 15k seconds of the above data during the quiet part in the middle. The third plot shows the ASD of 5k seconds of data from above, showing the quietest angle data I've ever seen :)

I'll add more about the investigation of the transfer function measurement, hopefully later tonight.

J. Kissel, J. Warner

In preparation for the planned power outage, Jim and I have brought all SUS and SEI systems to their SAFE mode -- except for ETMY -- such that there is no digital request for drive. Borja will continue to measure charge on ETMY ESD for a bit longer before moving EY to SAFE.

@DetChar -- The next few hours before the power outage is a great time to get free-swinging measurements of suspension resonances. 
All SUS (except ETMY) are in SAFE as of Aug 14 01:00 UTC.

Sheila, Kiwamu (a report from yesterday)

We switched the approach for assessing the IMC loss from the ring down measurement (alog 13319, alog 13280) to a cavity pole measurement.

The estimated cavity pole is 7745 Hz while the previous measurement was 8850 Hz which was done in February in 2013 (alog 5429).

Note that an expected value from the mirror transmissivity measurements (see the galaxy web) without taking losses into account is 9011 8625 Hz (Thanks Dan !).

(The setup)

We tried reproducing the same setup as the previous measurement (alog 5429). We used a PDA55 for monitoring the injected intensity modulation on the PSL. This is the one under the periscope i.e. H1:PSL-PERISCOPE_A_DC. Then we hooked up an SR785 to this PD and the IMC trans PD (H1:IMC-TRANS) which is an PDA100A on IOT2L. We drove the AOM with an amplitude of 200 mV and frequency band from 1 kHz to 100 kHz, swept sine. We did two kinds of measurement -- first, we measured the IMC cavity pole by driving the AOM and taking transfer function from the PSL periscope PD to the IMC-TRANS PD. Secondly, we measured the PD responses by taking the transfer function of the same PD, but without any IMC interference by misaligning MC2. Note that in order to perform the second measurement we moved the position of the PD to the IMC-REFL path such that it can observe the direct reflection from MC1. Again, these procedure are the same as the previous measurement.

(The result)

After taking the two transfer functions, we divided the IMC cavity pole transfer function by the PD response transfer function in order to reduce the effect of the PD responses. The below is the resultant transfer function and its fitting result.

I used the same fitting algorythm as Giacomo used (see alog 5541). The fitted cavity pole is at 7745 Hz. Since the data was noisy and showed a funny bump avobe 30 kHz, we excluded the data above it. Also, if we do not correct the PD response, the cavity pole is at 8380 Hz.

1600 - 1645 hrs. local -> Isolated and shut down aux. pump carts @ HAM1, HAM3, BSC3 and BSC1 -> Isolated and spun down turbos @ YBM, XBM and X-end.  Also, shut down corresponding QDP80s

I will be taking down the DMT system shortly in advance of the power outage.  It will not be back until later tomorrow. (WP 4796)

(Koji, Alexa, Dan)

We examined the beam path in HAM6 to OM1 in order to figure out the angle of the beam. We made measurements at four different points. Using an (x, y, z) coordinate system with z = up, y = East, x = South, we find at (all in mm):

Edge of table: (20.32, 0, 98)

Intermediate point 1: (0, 552.72, 95)

Intermediate point 2: (-25.4, 1219.2, 93)

OM1: (-40.64, 1574.8, 91)

The error of the measurement in height is ±1mm, and the error along the x, y axis is ±2.5mm. The attached layout shows the original (red) beam path and the new (green) beam path. From this layout, one can see the actual vs. measured angle deviation in height and along the hoirzontal plane.  Using the points above, we made a linear regression and determined the vertical angle of the beam to be 4.3 mrad. The attached plot shows the data with error bars and the linear fit. 

Investigation reveals that all (3) running turbos on site (YBM, XBM and X-end) shut down simultaneously at 1603 hrs. local time yesterday -> Coincidentally, this was only a few minutes prior to my opening of GV2 -> As such, my earlier theory of the XBM turbo tripping off on its safety valve pressure setpoint turned out not to be the case -> This is confirmed also by the fact that PT170A never came on scale.

Today at ~1230 hrs. local -> I spun-up to 100% rpm the troublesome XBM turbo by employing the technique of "loading" the rotor.  To do this, I maintained the turbo inlet pressure at ~ 0.2 torr by adjusting the "up-to-air" needle valve at the turbo's inlet while it spun-up -> Once at full speed, I shut off the air and eventually valved-in the turbo to the XBM volume.  


ERRORS in PRESSURE GAUGES
Also, the LHO vacuum equipment is beginning to show its age as we have been experiencing an increase in the failure rate of the site cold-cathode gauges (lifetime maturation) -> most noticeably PT180B, PT120B and PT170B are reading bogus values now for portions of their nominal range.  As of this writing, both the YBM and XBM turbo inlet CC gauges are reading 1.8 x 10-6 torr which is what I would expect for the recent history -> I would then guess the pressure at BSC2 to be 5-7 x 10-6 torr

(Dan, Koji, Masayuki, Alexa)

We measured the HAM6 septum angle using a laser pointer. We confirmed that there was no observable vertical component to the wedge angle, and then proceeded to measure the horizontal angle. We pointed the laser pointer such that the retro-reflected beam off the surface of the septum returned approximately directly back. Then we measured the distance from the second reflection to this point. This distance was 17mm. The distance from the laser pointer to the septum was measured to be 360mm.

This gives: wedge horizontal angle: 17/360 * 180/pi /2 /1.45 = 0.93 deg

In the equation above the factor of 2 comes from the optical lever effect. Meanwhile the factor of 1.45 comes from applying snells law with the index of refraction for glass and assuming the small angle approximation (see attached drawing).

This measurement was not extremely precise, but was close enough to the expected value of 0.75 deg.

In the attached picture, you will see the retro-reflected beam, which is almost ontop of the outgoing beam, and the second reflected beam. We used the ruler below to measure the separation.