Travis, Jason & Angus.	Oct 5th, 6th & 9th

The new ITMx has been welded and the violin modes of the fibres measured in air with the PUM clamped. The welding went quite smoothly apart from a couple of points. 
1)	The epoxy around the sapphire prism on one side of the PUM (+Y side) has charred due to heat from the welding of that fibre.
2)	The lengths of the horns on the PUM after fibre removal were not all exactly 6.0 mm above the ear, and this was not compensated for exactly with each fibre. The consequence is that the break-off values for one of the fibres (+X-Y) will be higher at the PUM and a bit lower at the ITM
The following fibres were used and the violin harmonics recorded

Posn	S/N		fund	2nd	3rd	4th	5th	(predicted in-vac)
+X+Y	S1400158 	502.45	994.8	1463.8	(1930)	[2390]	503.0
-X+Y	S1400137	503.96	997.85	1468.3	1931.6	(2391)	504.0
-X-Y    S1400164	504.71	1001.6	1472.4	1940.3	2408.3	504.6
+X-Y	S1400154	504.45	1002.6	1466.6	1936.4	2390.0	505.4

Accuracy is about +/- 0.05 for the fundamental, +/- 0.2 for the 2nd harmonic and the higher harmonics are generally +/- 0.5 or better, except for the ones in brackets which are worse. The round brackets are +/-1 and the square is +/-10 Hz (yes ten!).
It can be seen that the harmonics “cross” and that without this measurement it would be harder to determine which harmonic belongs to which fibre.
The pitch prediction from the fibre profiles was 0.1 mrad up (wrt PUM), the actual pitch is 0.3 mrad up. The roll and separation are as good as, or better than, the previous ITMx assembly. The yaw and pendulum frequencies were measured with +/- 0.005 Hz accuracy to 0.650 and 1.095 Hz respectively.
Attached are typical (linear) plots of the modes and a zip file of the original data files and excel files. Plus pics of the welds.
Fibre guards are on.

In anticipation of attaching AOSEMs to the OFI for HAM5, I laid out a string of the appropriate cables and AOSEMs next to the chamber on a staging table.  I've fastened to the table the clean-to-dirty ribbon-feedthru-simulator-cable to the table and Fil has run a grey temp out of vac cable from it to the sat amp located on the other side of the chamber.  So, the OFI guys can test fit and test the new AOSEMs and their brackets when ever they are ready.

The cables and AOSEMs are:

D1000234-88"  S/N 932

D1000225-230"  S/N S1104240

D0901065  S/N  525, 559, 511

The Noise eater has tripped and is currently NOT resettable. Jason and Peter are aware of this and are investigating it. An FRS ticket has been filed.

This morning I completed the weekly PSL FAMIS tasks.

HPO Pump Diode Current Adjust (FAMIS 8443)

With the ISS OFF, I adjusted the operating currents of the HPO DBs, changes summarized in the below table.  A screenshot of the PSL Beckhoff main screen is attached for future reference.

I did not adjust the DB operating temperatures.  The HPO is now outputting 154.4 W and the ISS is back ON.  This completes FAMIS 8443.

PSL Power Watchdog Reset (FAMIS 3671)

I reset both PSL power watchdogs at 16:19 UTC (9:19 PDT).  This completes FAMIS 3671.

Yesterday we tied in ±18V to SUS-R3 and SUS-R4. We now have our standard 8 awg shielded cable running from the CER mezzanine down to the LVEA racks. The following electronics were moved to the new ±18V line: Op Lever whitening chassis, CPS Timing Fanout, and the SAT Amp units. Some of the "temporary" cabling used to previously power these electronics will be removed.

Both TCS LVEA racks are sharing their own dedicated power supplies for ±18V and ±24V. One thing to note is that the CPS Timing Fanout in TCS-R2 (next to BSC1) is being powered by TCS rack power.

The new SQZ-R1 rack is now powered by its own dedicated ±18V power supplies. We used the the existing ±24V from ISC-R3/R5 since the current draw is minimal.

The hex nut integral to the actuation lead screw on the 1.5" isolation valve separating VBOC's RGA from the oven chamber physically broke off! -> Venting the RGA was required to replace this valve.  As such, VBOC will be out-of-service for a week or more while the RGA volume bakes-out at high temperature etc...  

Kyle R., Arnab D., Rakesh K. 

Today we adjusted the "ATM" potentiometer on the new parani gauge (local electronics unit) but could only achieve a minimum value of 906 torr indication on CDS.  This is too high.  The actual pressure under these conditions is closer to 760 - 790 torr -> The measured voltage supplied to the gauge electronics is 24.5 VDC and the output signal from the sensor electronics, 5.6 VDC, which is consistent with the CDS-converted value of 906 torr.  Any voltage drops across signal wiring connections between the gauge and the CDS rack should result in a CDS value which would be biased to less than the actual value, not more than the actual value.  

We will continue troubleshooting at the next opportunity.  

Betsy, Hugh, TJ

Last week Betsy put the heater on the table and today Hugh checked it's vertical center with an auto-level. Some washers were added to get it as close to center as possible, which ended up around 0.4mm high. Betsy and I then had to wiggle the assembly into place, and rotate the entire gold ceramic holder to allow the screws on the outside to clear the OSEM brackets. The heater is currently sitting ~6mm away from the back of the SR3 optic and it is plugged into the feed through.

Picture attached.

With new redlines on the HAM5/2 baffles I rotated our below table baffles (beard baffles) that Jim and I had already installed. LLO did this to help cover up more of the exposed metal on the table (see <a href="https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=36113">LLOalog36113</a>), so while I was already in HAM5 I did some 180's.

No picture yet, I'm hoping to get some when we can look from HAM4.

This morning Mark, Tyler, Bubba, and I attached the install arm on to the West side of the North door on HAM5. We couldn't find the tub of bolts dedicated to this assembly, but found some others nearby (which included some of the door bolts, that we will need to remember to put back when we are finished). The arm is currently only held on with 3 of the 4 bolts that were previously used with this arm. HEPI blocked access from the front to the lower right thru hole, and there was not enough clearance in the back. Perhaps this arm hasn't been used wiht the new style HEPI's yet? Bubba doesn't think the missing bolt will cause any problems and a possible fix with a shorter piece of all-thread is in the works.

Picture attached of the arm installed but all covered up. (Forgot to take pictures until we were walking away.)

Cheryl V., Ed M.

This afternoon we installed an access platform into HAM2 on the SW corner of the ISI table for accessing IM3.

Day's Log Of Activities

• 15:57UTC (8:57amPDT) HAM5 Arm prep work (TJ)
• 16:03-17:10 Moving West Crane to BSC2 for fall protection for Vac work at BSC2 chamber (Kyle)
• 16:07 Dust Monitor 30 (BSC3) out, power cylcling (Jeff)
• 16:20 Picking up cleanroom garb (Travis)
• 16:23 HAM6 septum work, installing new viewport (Hugh, Jim, Greg, & Gerardo)
• 16:30 DC Power Distribution (WP#7179) work this morning (Fil, Richard, until "lunch")
• 16:49 Beer Garden Test Mass measurements (Travis & Angus, morning & afternoon)
• 17:01 HAM4-ISI & OM1 (HAM6) both tripped (& were redamped)
• 17:09 Restarting h1susauxh56 model [will require DAQ restart] (Dave & Jeff K)
  • For specifics, please see his alog.
• 17:12 LVEA HVAC work begins
  • Both dampers OFF for ~1st hour
  • Then one damper back ON & monitored (Bubba)
• 17:17 Restarting h1susopo (Dave)
• 17:25 IO Work before & after lunch (Cheryl & Ed)
• 18:14-19:31 MY cleaning (Karen)
• 18:18 Quarterly check of Dust monitors at both end stations (Jeff B)
• 20:22 Survey elevation of SR3 heater + Install 5-Way cross feedthru (Hugh,TJ)
• 20:56 CER work (Richard)
• 21:54 HAM5 (Betsy)
• 22:10 Checking ALS table (Sheila)

Jeff, Sheila, Dave:

to show off my recently acquired skills in drawing ellipses using gimp, the attached plot shows the three main changes made to the LHO SITEMAP as part of SQZ install.

1. PEM has been reduced from two to one button. To permit this, I have replaced the links to building detail screens with a launcher screen.

2. OPS and O1 (sic) screens have been merged to the OPS button

3. new SQZ button added.

  Checked all monitors except PSL (will do on Wed when in for other work), and #2 and #10 in the LVEA. These are in running cleanrooms with vent work underway. Will check these early in the morning before the work day starts. 

   The rest of the monitors are working within specifications.   

A. Bell, J. Oberling, T. Sadecki

ITMx has been successfully hung as a newly welded monolithic.  I'll leave it to Jason to post the actual numbers, but the PUM to TM differential pitch better than the old version of ITMx.  Now to put it back together in chamber next week.

I have compiled the results of in-air measurements during installation and in-vacuum measurements from the alogs; 14231 LLO (including corrections mentioned in alogs 21652 and 27901) and 17610 at LHO (including corrections mentioned on the comments).

In the case when a frequency split is shown on in-vacuum measurements we have taken the average of both frequencies. I have grouped these numbers per front and back fibres, then per test mass and then per detector, finally I obtained the difference as (in-vacuum – in-air) including the sign:

We notice that in most cases the frequency difference is always positive, so frequency increases when moving the suspension to in-vacuum.

The increase in frequency is always a few hundred mHz (mean of 0.3Hz and median of 0.4Hz), with a clear outlier on LLO_ITMY_FL (which as explained here seems to be involved with uncertainty in the identification).

There is not clear difference in frequency variation between front and back fibres (especially no sign difference) which would indicate pitch effect.

However, notice that as per the Technical document T1700399 the expected increase in frequency due to buoyancy is of 0.14Hz, and the variation in frequency due to pitch angles of 2mHz is of 0.33Hz (although that would be an opposite sign change between front and back fibres). Therefore while the observed changes cannot be explained through pitch and buoyancy alone, they are of the same order.