Prior to venting, I sprayed helium around the welds which join the thin-wall MC tube to the thick flanges.  The LD background was 3.5 x 10-9 torr*L/sec -> no responses.  I did not spray all of the welds on the MC nozzles, roll seams or roll butt joints, however.  

Also, PT120A wasn't working today.  I think that I had drug my fall protection tether across the gauge pair the other day during leak testing and must have interrupted the cable connection.  I eventually had to remove and re-installed its cable to get it going which fixed it.  

Cheryl moving TCS lasers into HAM 6 bay
Kyle soft closed GV-5, venting vertex for ISI install into HAM5

Restarted models on the sei test stand (stormy), cpu for the iop was pegged.

The H2 ITMY and ETMY have been re-centered with the cavity beam locked at approximately 10:05 for ITMY and 10:55 for ETMY.  The cavity was locked at the time.

One particular note, all of the electronics for the ETMY optical levers (laser, whitening chassis, power supply) were running off a power strip that was disconnected sometime in the past few days and this caused a loss in signal.  Please don't do this.

Morning (8-noon) Notes

OAT Work:  Aiden & crew had the reins for Ring Heater work

Craning activity:  HAM5 ISI had it's Container top removed and the ISI is staged in a cleanroom

H2 ITM/BS CPU Meter went to a MINOR alarm state (value = 13) at 8:27am

Thomas centering oplevs for ITMy & ETMy

Mark Dodson making measurements around BSC8 10-10:15

Kyle is inquiring about venting section of HAM5.

Patrick is covering the afternoon.

I turned on the Ring Heater this morning to a nominal 30W of electrical power. We've yet to fully determine the ratio of the radiated power to electrical power, but the most recent number is approximately 2.5W radiated power per 6W electrical power.

I measured the spherical power of the HWS beam -  probing the ETM thermal lens and surface deformation and compared it to the results from a simple COMSOL model of the predicted thermal lens + surface deformation [no fitting]. The results are shown in the attached plot. Bear in mind that the scale of the predicted model will be affected by the delivered power (dependent on the radiated to electrical power ratio) and that the HWS is still operating on a nominal calibration for the optical system - rather than a measured calibration. 

The results are quite similar but there are obvious differences in the time constant. At the moment I would put that down to the simplicity of the COMSOL model - it doesn't include the flats on the sides of the ETM, or the reaction mass or the time constant associated with the ring heater itself.

However, this is the first real aLIGO measurement of thermal lensing with the HWS.

Caution: this is not solely the surface curvature of the ETM - the optical path distortion from the thermal lens is roughly 10x larger than that of the surface curvature.

10-Aug-2012 11:34AM - replaced plot. I had added the incorrect sign to the surface deformation in the model. I've fixed this.

The daqd process on h2nds0 died, the log file shows 
...
Ask for retransmission of 6 packets; port 7097 (repeated 50 times)
Have to skip 6 packets (retry limit exceeded)



Didn't automatically restart because /var/run/daqd.pid didn't get erased.
I manually restarted the process.

The computer h2nds1 was completely unresponsive.  No error message appeared on the console.  Restarted computer.

With both nds servers down, it was impossible to get channel data for any software that needed it.

Suggest more reliable method of determining if daqd is actually running, along with some bug fixing.

I'm running repeated cavity transfer functions to monitor changes in the cavity during the ring heater test. This means that Excitation B on Common Mode Board A will be left on for the duration of the test (~12 h), and that the GPIB unit on the SR785 at EY is in use and should not be contacted.

Thomas tried to add a python script (with extension .py) to his LHO aLOG 3758, but was thwarted and needed to change the extension to .txt in order upload it. Please add this to the acceptable files.

Checking to see if anyone had centered the optical levers in hopes to grab a spectra of the Commissioning Team's awesome new spectra, I found that 
- ETMY was still not centered, but with the corrected calibration
- ITMY was centered, but had the old calibration
(queue sad trombone).

I've restored the ITMY calibration that I installed yesterday morning.

I see that H2SUSITMY and H2SUSETMY were rebooted some time later in the day yesterday, according to the ops log, but I don't see any further details/aLOGs as to why...
My guess is that safe.snap had not been updated since those calibrations were installed (though the right calibration stuck for ETMY...). 

I haven't gathered a new safe.snap myself, I'll will wait for local staff, as I'm not sure about the state of the cavity. But, when you do, remember there's a nifty script here:
${userapps}/release/cds/common/scripts/makeSafeBackup
which can use to make a new safe.snap in the appropriate reboot location, and it also makes a copy in the appropriate userapps directory (with the model name appended), e.g. 

0$ cd /opt/rtcds/userapps/release/cds/common/scripts/
0$ ./makeSafeBackup sus h2susitmy
0$ 

which puts files in
/opt/rtcds/lho/h2/target/h2susitmy/h2susitmyepics/burt/safe.snap
and
/opt/rtcds/userapps/release/sus/h2/burtfiles/h2susitmy_safe.snap

Today, we finally stuffed the optic in the PR2 suspension and started correcting it's roll.  We will finish suspending it tomorrow.  As well, Filiberto and Travis sorted out a cable issue on the PR2 chamberside testing setup.  Since, for the moment, we cannot test both MC2 and PR2 simulatenously, and PR2 is our higher priority, we have "given" the shared cable between them to PR2 in hopes of getting it's full data set run over the next 4 business days.  Seek Filiberto if for some reason you need it moved back to MC2 (possibly to facilitate it's testing later next week).

The Arm is locked, as off 03:24:00 UTC (20:24h local time).

The various controls are in the state listed below.

Channel of interest is 'H2:ALS-Y_ARM_LONG_IN1_DQ' and has units of nm (and is sampled at 16k).

HPI State:

All running fine. The cavity feedback (off load) at low frequencies to HPI ETMY, with a UGF of ~1 mHz. ETMY_ISCINF_LONG has a a 250k nm limit on the output (I got an effective limit of 200k nm on the output of the signal ISC sends into the RFM).

ISI State:

Stage 1, (ITM/ETM) X/Y 250mHz blend other at 750mHz blend

Stage 2: (ITM/ETM) XY 100mHz other 750mHz blend.

Quad Sate:

ETM: M0 damping on, L1 L/P damping only, L2 no damping (watch dog off), L3 no damping

ITM: M0 damping on, L1 L/P damping only, L2 no damping (watch dog off), L3 no damping (watch dog off)

Attached is an initial spectrum .... the frequency noise has dropped nicely! (due to 3791)

I was not able to close the PZT servo loop which keep the beams nice and tight lock to the TMS. It turned out that the filter switches of thewhitening board 'were enganged' but not ON. I toggled all the buttons on the medm screens which seemed to fix the problem.

The beam is nicely locked to the TMS ...

Elli, Robert, Bram

We had another look into the RefCav. I think we found the culprit ... the free-space to fiber coupler behind the RefCav is retro reflecting back to the cavity. We use an angle-cleaved fiber cut to remidy this, but not enough. When we block the beam to the fiber coupler, intensity flickering on the CCD is gone. You can still see he peaks on the transmitted diode, but they are most likely intensity fluctuations (which is we 'immune' to).

By the lack of finding any quarter waveplates, we placed a half waveplate, a PBS and a faraday rotator after the first steering mirror behind the cavity to capture any back reflections (from the fiber coupler, photodiode and CCD).

Now we will need to relock the arm cavity to see if it made any improvements ..

CoreyG ,HugoP

Transfer functions ran overnight yesterday. Unwanted resonances are present in the vicinity of 130Hz, on all DOF. The usual suspect is then the 600lbs payload mass set on top of the ISI. One can hear it resonating when being hit. The washers it was sat on were too close from each other. Corey and I lifted this top mass with a fork lift and reset the washers. The mass would vibrate way less when being hit afterwards.

Transfer functions are running overnight.