Daily Ops Log

08:15 LVEA is LASER SAFE 

08:30 Automated message about 200 West Area Emergency Drill - e-mail sent out LHO-All

08:44 Vacuum status is normal IFO wide. Corner station is pumping down and currently at 10 ^-6 torr.

09:04 Travis -out to LVEA to look for cable clamps for Jim

09:17 Gerardo -down to End-X to test power supply for ION pump

09:18 200 West Area Drill is terminated

09:20 Praxxair in for N₂ delivery

09:30 Visitor arrived on-site for tour

09:40 Cyrus-to End-X to check out FMCS "thing" ?

09:54 Dale -will be bringing in a tour group around 11:00

09:56 Koji - into LVEA for capton washer installation in HAM6

10:13 Cyrus - back from End-X

10:18 Jason -OpLev work @ HAM3. Also cable swap on SR3

10:30 Gerardo -back from End-X

10:37 Cyrus -Back out to End-X to swap parts

10:38 Praxxair out

11:02 Cyrus - returns! (cue music and credits)

11:15 Tour group in control room

13:27 Gerardo -to End-X to test ION pump power supplies

13:45 Cris - cleaning at X-End

14:40 Cris - back from End -X

15:30 LVEA IS LASER HAZARD

LVEA LASER STATUS

@ ~15:30 LVEA is LASER HAZARD

Dust Monitors - Vacuum pump Dead

Vacuum pump (located in the mechanical room) that feeds some of the dust monitors is no longer working. Trying to locate old unit.

Filiberto Clara

H1 EX BRS Tuneup

K. Venkateswara, J. Kissel

Noticed BRS had been rung up with X-End activity (see LHO aLOG 13533).
- Gravity dance to damp the 8.8 [mHz] mode
- Changed very-low-frequency high-pass from 1 [mHz] to 0.5 [mHz], to improve signal fidelity for subtraction. 1 [mHz] was adding ~10 [deg] of phase to the signal at 10 [mHz] -- too much in the region we wish to use the BRS signal for GND T240.
- restarted code at ~11:45p PDT

Notes for future gravity dances:
- When Tilt signal is on the upper-half of its sign wave, one needs to stand on the North (+X) side, if lower-half on the south (-X) side.
- Transition, or start standing on a given side at the amplitude peak
- As the resonance gets damped, you need to stand on a given side for less and less time
- +/- 500 [ct] amplitude = need to stand on one side for a full half cycle (~30-50 seconds), +/-50 [ct] amplitude = only a few seconds at a time
- +/- 25 counts is good enough. 

Note on determining frequency for high-pass: 
- filter coefficient = (1 - (desired freq)/(sampling freq))
- Sampling frequency = 50 [Hz], desired frequency = 5e-4 [Hz] ==> filter coefficient = 0.99998;

SR3 OPLEV laser DC regulator added

SR3 Oplev laser dc S/N 194 DC regulator D1200461 added 

MC1 and MC3 GigEs realigned

I physically realigned the MC1 and MC3 GigE cameras (h1cam11 and h1cam12 respectively) because they had been misaligned spontaneously. The attached are the snapshots of their views to show how they look like after the realignment.

HAM6 Purge Air

Purge air is on while Jim works there.

Measured DC couplings on HSTS

Based on the matlab tf measurements taken after coil balancing on SRM SR2 and MC2, and in order to have a physical idea of what's happening, I calculated the DC coupling between longitudinal motion and test mass angular motion for the three stages of the three HSTS suspensions. The results are summarized in the attached spreadsheed, and the numbers in the table are from the transfer function measurements at 0.01Hz (7 averages using schroeder phase drive), and assuming the coherence was good. The transfer functions results are summarized in the second attachment.

To note from the results :
*Length to pitch coupling is roughly ~2rad/m and length to yaw is ~1rad/m.
*M2 length to M3 yaw coupling of SR2 is higher because of the broken actuator.
*M1 length to M3 yaw as well as M3 length to M3 yaw has a different phase than the other sus tested.

The plots can be generated by using the script living in trunk/HSTS/Common/Matlabtools/plothsts_matlabtfs_cross_levels.m
The matlab tf results can be found under /ligo/svncommon/SusSVN/sus/trunk/HSTS/{optic}/{level}/Data

H1 EX BRS Installation, Day 14: Gravity gradient noise on the BRS (from people)

K. Venkateswara

This morning I noticed that the BRS was rung up to large amplitudes (500 microrad), so I looked at the data from yesterday and noticed two main incidents/causes: Borja and Sheila were near the BRS at ~ 3:30 PM but that disturbance was small and did not drive it up the resonance much. The ASD and time series of the first disturbance is shown in the first attached file.

The second disturbance at ~5 PM was much bigger and really drove up the resonane of the bar from 50 nrad to 500 nrad as shown in the second file (the y-axis scale in the time series should be in nrad not rad). I'm not sure who this was yet. The gravity gradient from a person standing next to the balance is very large and can easily drive up (or down) the resonance amplitude to microrads. As the decay time is ~two days due to the high Q, it will take a long time for the bar to return to normal amplitudes. Furthermore, due to the non-linearities of the autocollimator, the harmonics of the fundamental become visible and destroy coherence with the seismometer as visible in the third file.

This is a known problem due to the open loop operation of the BRS and we hope to address it very soon with some simple feedback/damping loop. In the meantime, I would like to ask that people stay away from the BRS unless necessary. Gravity gradient torque falls off as distance^3, so even an extra  distance of 2-3 meters is sufficient to keep the influence small. Grvaity gradient torques are also filtered by the resonance of the balance, so if you move by it fast, that is generally okay.

When it does get rung up, it is kind of fun to drive it back down using your gravity :)

dark offsets adjusted

While the laser is shuttered this morning, I adjusted dark offsets for MC2 trans QPD, IM4 trans QPD (I changed the whitening gain on these yesterday to match the gain settings paul used for the calibration (alog 9716 ).  I also adjusted IMC trans and refl PD dark offsets.

LVEA LASER STATUS

The LVEA is now LASER SAFE

CDS model and DAQ restart report, Wednesday 20th August 2014

model restarts logged for Wed 20/Aug/2014
2014_08_20 15:09 h1broadcast0
2014_08_20 15:09 h1dc0
2014_08_20 15:09 h1fw0
2014_08_20 15:09 h1fw1
2014_08_20 15:09 h1nds0
2014_08_20 15:09 h1nds1
2014_08_20 15:10 h1dc0
2014_08_20 15:12 h1broadcast0
2014_08_20 15:12 h1fw0
2014_08_20 15:12 h1fw1
2014_08_20 15:12 h1nds0
2014_08_20 15:12 h1nds1

no unexpected restarts, DAQ reconfiguration.

HAM6 alignment - VICTORIOUS!

Alexa Dan Fil Keita Koji

This afternoon we brought the second of Koji's three OMC children under control.

After working in the morning to understand the quadrant layout of the OMC QPDs, we were able to close simple diagonalized versions of the OMC QPD alignment loops to stabilize the beam in the chamber.  With Fil's help we enabled the high voltage to the PZT driver (in the process finding a cable that was plugged into the wrong slot on the AI chassis).  Before fiddling with the high voltage we checked that the HV readbacks were working as advertised.  We were able to drive the high-voltage PZT in a triangle wave across its entire range (0 -> 100V) and see flashes in the OMC.  We tried to improve the alignment by watching the flashes and searching for a clear 00 mode, but this turned out to be fruitless, probably because the beam is moving too much.

We proceeded to align the rest of the beam paths on the HAM6 table: OMC REFL QPDs, AS WFS, and the OMC REFL beam through the viewport.  For a while we were confused by a mirror on a too-short pedestal; Keita showed up at a lucky moment and fixed it.  The beam has been aligned onto all of the QPDs in the vacuum.

We should be able to lock the OMC tomorrow and study the alignment (and, possibly, take a first stab at the mode matching).  At the moment, the beam is moving a lot in pitch; this motion is due to something upstream of HAM6.  We suspect SR3 and the ISI table in HAM5, but it could be something else.  This motion really needs to be fixed before any robust OMC locking can happen, either by stabilizing the source or constructing a more robust OMC QPD servo.  While we flashed the OMC Koji was able to visualize the modes inside the cavity, and the 00 mode was there.

Before leaving the chamber we relieved the yaw and pitch bias on the OM tip-tilts and centered the OSEMs, and then clamped the tip-tilts to the table.  The TTs are in good shape.  One of the OM3 OSEM cables can potentially slip and block the beam to the AS WFS, we should find a way to clamp this cable in a safe place.

Tomorrow we need to install the kapton washers on the pico drivers.  We still need to align the OMC TRANS path, but we probably have to lock the OMC on a fairly strong 00 mode in order to see the beam.  In principle OMC TRANS can be aligned after the north door is installed.

Now that we have a beam we can do RF balancing of the AS WFS, if that's necessary.

We'd like to try to put the north door on HAM6 by the end of the day tomorrow.  Two other things need to happen before we can attach the door: cable dressing and table balancing by the SEI crew, and a check for ground loops.  (These steps may need some iteration if the ground loop situation is bad.)

For now the purge air has been turned off to give the mirrors a rest.

end X FMCS readbacks invalid

It appears that the end X FMCS EPICS readbacks went invalid at around 08/19/2014 23:35 UTC (from a trend of H0:FMC-EX_VEA_202A_DEGF). I checked the FMCS Windows computer and they appear to be down there as well. I'm not sure how to fix this, so I will email John.

J. Kissel, J. Worden

John called and suggested we reboot the FMCS machine in the back of the control room. After 20 minutes of windows updates, I was able to log back in, but the status of the X-end did not change. We're both unsure if there's any program to be restarted, but John thinks not. The in-vacuum components (SEI / SUS), nor to the ground instruments (T240 / BRS / PEM) and other PEM instruments show no sign of bad news, and the vacuum pressure looks reasonable, so we assume this is just a failure of the readback system. John will look into the problem when he's back in on Friday.

This is a known issue with the network hubs that are used in the mechanical room to connect the FMCS controller to the network (along with a couple other systems); they are flaky after power outages, and just in general.  In this case, I changed out the hardware since it's been flaky over the past few days and the usual power on/power off thing didn't clear it up today.  The long term fix is to pull more cable so that these things can be directly connected to a real switch.

P.S.  Only the vacuum system shares any common infrastructure with FMCS - the operation (or non-operation) of any 'fast' front end EPICS system is not a useful indicator for problems limited to either of these (vacuum/FMCS).

Reverted to Turbo Pump at Y-End

I closed the gate valve for the ion pump @ 4:40 pm today. Turbo pump gate valve was opened a few minutes later.