On Thursday, 8 December 2011, I performed a series of resistance checks to determine the health of the ring heater installed in the ITMY cartridge on H2.  The findings can be summarized as follows:

The findings can be summarized as follows:
Average ring heater resistance (in-vac wiring subtracted from measurement) = 35.6 ohms
Average resistance of a single wire leading to the heater or RTD starting at the air side pins of the vacuum feedthrough = 1.95 ohms
Upper ring heater RTD(in-vac wiring subtracted from measurement) = Not connected, damaged during installation
Lower ring heater RTD(in-vac wiring subtracted from measurement) = 108.8 ohms (this corresponds to a temperature of 22.4 C, which is reasonable)

Attached is a diagram showing the test setup and a spreadsheet used to take data.  In general, the TCS ring heater subsystem is supposed to provide two heaters (upper and lower halves of a circle), and two 100 ohm RTDs (Resistance Temperature Detectors). The RTDs give an indication of the temperature of the associated ring heater.  The resistance of the RTD varies predictably as a function of temperature.  

After measuring few amplitude spectral densities of CPS and GS13 on the HAM-ISI, we were surprised by some narrow peaks on CPS between 10 and 100Hz (cf LHO_ISI_HAM10_ASD_m_CPS_GS13_L4C_Locked_vs_Unlocked_2011_12_05.pdf) and these peaks are less visible on GS13 spectra.  We were actually concerned by the grounding of the new shield installed on the CPS cables. We took measurements in different configurations to find the source of the peaks:

-          Fans ON vs Fans OFF: We only saw minor differences

-          We measured a spectra of a locked CPS using the jig  in several configurations:

o   Shield not connected to the ground

o   Shield connected to the ground

The two spectra (CPS_Noise_Investigation.pdf) were identical and without any features in the 10-100Hz bandwidth (Noise floor at 7e-10 m/sqrt Hz). It confirms that CPSs are not picking up electric noise but are actually seeing a real motion. Due to the passive isolation provided by the ISI above 1Hz, amplitudes of the narrow peaks (probably motors) are reduced (in the unlocked and the so-called locked configurations).

We got the more improved version of the 4.5" Dual Triax Feedthru from C&B this afternoon and promptly installed them on BSC8.  We added six of these and also two more of the 3Pin Power Feedthrus for the EM Actuators.  So aside from the single ESD Feedthru still being improved at the vendor, that is all of the Feedthrus for BSC8.

These are installed but not torqued up--I'll get Apollo to do that Thursday.  Once that is complete, the Cable trays can be replaced, cables run and then we can start powering up the ISI.  Also then the HEPI Dial Indicators can be installed for IAS moves.

Thanks to Mitchell, Calib and Devil-Dog Ed.

Jim & Greg carefully positioned the Keel Masses and symmetrically located the Stage2 side wall masses(D071200).  The lockers are now loose so that means we are close to being balanced.  Good news this is as models are looking close to realistic.

The ISI however remains locked.  Once all the in-air cabling is run and we can power up the CPSs (Capacitive Position Sensors,) we'll use those to fine tune the mass distribution for balance, modulo any IAS tweaking for table level.

Attached is a photo of Greg fine tuning the last of the four 150lbs Keel Ballast Mass Stacks.

Corey, Patrick

A dust monitor has been put in the clean room over BSC8. The channel for counts > .5 microns is H0:PEM-LVEA_DST15_5. It has been added to the alarm handler and the H0PEM_DUST_GIF_ILIGO.adl medm screen.

Attached are plots of dust counts > .5 microns.

(Corey, Mark, Randy, Zach)

After The UofFlorida group cleared off the Optics Table, the first H1 SEI iLIGO stack was removed.  Spent about an hour first relieving Spring Cups for the external Scissors Tables.  We then removed everything above the Support Table (that took another 90-120min).  We left it staged outside BSC1....need to figure out a pathway to get it outta here (it is destined for Dale as an Outreach Display).

Note:  One of the 400lb Leg Elements had damaged threads for one of its eyebolt holes, so we lifted it out with only 2 eye-bolts (vs the standard 3).

For the record, the LASTI PUM glass with prisms/ears weighs 39,689 g.  The ETMy Test Mass (ETM04) weighs 39,626g.

The modal frequencies of the ETMY monolithic section were measured yesterday.
	frequency (Hz)	     uncertainty
Longitudinal	0.651	     0.002
Pitch	        1.101	     0.002
Yaw	        1.092	     0.002
Vertical	6.72	        0.03
Roll (?)	9.66	        0.1

Fibre HR right	508.6	
fibre HR left	513.7	
fibre AR right	508.4	
fibre AR left	512.5	

The pitch and yaw modes are very close together. The feature at 9.7 Hz was guessed to be the roll mode. The violin mode measurement did not give a response as clear as normal but there are sharp features at the expected frequency and they make some sense in that the differential tension would indicate about 1/2 a mrad of excess pitch and we see 1 mrad 

Betsy & Thomas
This afternoon we attached (albiet loosely for now) the FMy one-arm elliptical baffle to the Fmy SUS structure.  This tops off the payload for this ISI table, so fine balancing can finish.

The LHO aLOG will be receiving a software update Thursday evening 15 Dec 2011 around 4pm pacific time.

The update will include at least:
* improvements to comments such that they can be edited by the author within 24 hours of posting
* comments will show up in searches
* comments can be linked to
* comments inherit the section and task of the parent entry
* some work to better handle updates to log entries when a login times out

The updates will be applied at the LLO site at the convenience of the LLO admins.

There are other pending system updates that should be applied.  So the update time will also be used to patch the OS.

Please save all pending entries to the aLOG prior to 4pm Thursday (pacific time).  The aLOG should only be down for a few minutes but please hold off on posting until notified (I will post an entry in the aLOG mentioning the completion of the updates).

According to E1100690-v8_WBSC8 Initial Alignment Procedure:

"The local BSC chamber coordinate system origin is nominally located 65.421 in [1661.7 mm] below the BSC-ISI optics table surface."
This would be the end of it except the chambers aren't necessarily exactly positioned on the global coordinate system.  The Global vertical zero is 0.1mm above the local gravity zero at BSC8-See T1100187 & T980044.  Our survey yesterday puts the Optical Table at 1662.6mm above the local level where BSC2 center is 0,0,0.  We subtract the 0.1mm from our survey result to put the elevation of the Optical Table into the global frame.  So the Optical Table is 1662.6 - 0.1 - 1661.7 = 0.8mm higher than nominal.  Not too bad since we set the support tubes 15 to 30mils high shooting the bottom side of the support tubes out side the chamber.  I was expecting some depression when the Cartridge landed but we didn't measure that as the dial indicators were no installed.

Any way, the level of the Optical Table is not to spec according to the requirement in E1100690 although I didn't think the requirement was as low as .1mrads; currently we have 0.53mrads.  However the elevation is within spec, if, if the ITM was not too far off in spec when it was measured at the test stand.  You know, the errors may combine to be fine or they may conspire to take the ITM out of position vertically.  I don't know that yet.  Regardless, the level will have to be tweaked anyway so we can fine tune the elevation as well.

If anyone doesn't understand my surveying notes or other gyrations, please feel free to ask.

Attached are plots of dust counts > .5 microns. Communication was lost to the dust monitors in the LVEA for a period this afternoon when the Comtrol lost power. Communication to the dust monitor in the LVEA at location 11 (H0:PEM-LVEA_DST11_5) was lost briefly earlier to that for what I believe may also have been a glitch in the power to the Comtrol.

We did a Differential Elevation Survey of the BSC8 Optical Table this afternoon.  Attached is my survey note page(just the right side.)

We observed the mon TP202 (see T1100187) which was surveyed wrt BSC2 way back.  Then looked in the chamber where Jim held the rod up against the Optical Table.  We took several shots.   I then kicked a leg of the Level and shot again and turned back to the starting monument.  My survey closed to within 0.1mm--this means I at least didn't read any numbers wrong.
All the elevation on the Optical Table were within 0.5mm.  This is good in that we leveled the Support Tubes from the outside quite awhile ago and have since pulled the iLIGO CAS stack and swapped in HEPI and the Crossbeams are currently sitting on mechanical stops.  I wouldn't have been too surprised if the table had been more out of level. I believe this puts the table very close to our requirement of within .5mrad level.  This of course can (will?) be repeated once we float the optical--we certainly can get it more level.

The average of the 5 shots on the table is 1662.6mm above BSC2(0,0,0).  That is in local elevation.  We subtract 0.1mm to put that in the Global frame.

I don't know what the Optical Table elevation should be at this point, which is good, that way you know I'm not cheating!  I'll look into this or ask someone and update you all soon!

Main entries have a link in the upper right corner such that one can provide direct links to log entries in emails, etc. This should also be the case for comments. Perhaps it's best if the link takes you to a page that has both the main entry, the comment itself, and any other comments associated with that entry (I fear that a direct link would show *only* the comment on the resulting page, like it does for the main entries -- I don't want this, it's imperative to see the context of the comment). However, the comment should somehow be highlighted to show that "it's *this* comment I wanted to show you."


On a related note, if you try to link directly to a comment by replacing the "callRep" at the end of any normal entry's URL for with one for a comment the page turns up blank.

i.e. Take the URL for entry 1874,
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=1874

and replace the callRep for the corresponding comment to that entry,
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=1880

and you get zilch.

This afternoon, after the final B&K hammer measurements were complete, and SEI locked the ISI and began their preps, I began securing the FMy and ITMy for lift-off.  Because the First COntact that was on the ITMy HR was many months old, and had been peeled down for IAS purposes numerous times over the last 2 months, I removed it and put a fresh coat on, including a new tab at the top.  I observed a lot of particulate on the optic after the peel and attempted to remove them with alpha swabs and the N2 gun (gun also used intermittently during FC removal).  This was cumbersome and while doing it I (and Corey over my shoulder) noticed some streaking pattern not from the First Contact, as well as some First Contact PEEK mesh patterning on the optic.  More pictures to come.  So, I gave up on the dabbing and blowing and reapplied the new FC coating.

Then, I secured all of the EQ stops on both the FMy and ITMy, with the exceptions of:
- 2 nuts (missing) - one on each UIM side stops, and
- the ITMy Top Mass Blade Stops, which require removing the Top Mass BOSEMs.  The masses and blades above and below are rock solid however, so this is fine.

I then added the new "finger" assembly which acts as a 20mm gap stop between the ITMy AR and the CP HR.  This assembly, however hangs down below the QUAD structure and may be a problem for the cartridge, but is easy to remove tomorrow if needed.

I also added the transport pins to the vibration absorbers on both suspensions.

I covered the FMy.

Adding a comment should by default have the same section and task as main entry.

While continuing to be logged in, after posting a comment, one should be able to edit comments that you've written in a similar fashion as the main entry.

Comments do not show up as results of search queries for them (I've tested by searching for entry ID #, author name, and keyword search).