Opened the PLL CM board chassis (S1002641) and Installed a notch filter daughter board S1300952 in the fast option slot. The notch frequency is about 290kHz now.

Put a timing comparator in the remote rack.

Recalibrated the DC diodes (fiber power, fiber wrong pol monitor, BBPD).

Auto locker worked with these things in place.

One odd thing was, when we started working the beat note was -40dBm or something, a big decrease from yesterday.

Then we started calibrating things, touched some steering mirrors to center the beam on DCPDs and such.

Then something happened, suddenly we're back to -10dBm beat note. We couldn't find out any obvious cause for this.

   The excess grout found on the Op-Lev receiver pier at End-Y has been removed. The grout was kept damp during the removal process to hold down dust contamination. Dust counts were monitored during the process and although elevated no readings over 9000 0.3 micron particles per sample time were recorded. The surrounding floor area has been recleaned.   

no restarts reported.

I spent today working on the high isolation filters for ETMY, and was able to install them today. However, when I went to tried to turn them on, I found a 30-ish hz peak in my seismometer spectra that seems to be ringing up the ISI. It's there even with the damping off, so something is creating some ground motion out there. RichM and I went down and turned the last 2 cleanrooms off, but the peak is still there. Rich noted the scroll pump was still on  but was doubtful that would cause the problem. The peak is clearly visible in the attached plot, this is after we turned everything off.

We adjusted the fiber polarization box so we don't waste much fiber power.

We measured the beam profile of the fiber beam as well as the Prometheus red beam, and the latter has a much larger divergence angle.

We changed the position of the lens for the Prometheus such that it doesn't converge so quickly.

We scanned the temperature slowly and found the beat note. There seem to be two good temperature range, at around 35.62 and 33.77 deg C. The beat note was huge, -8dbm at 120MHz for the latter temperature.

We then locked the PLL (now it's fast only, as the frequency counter is not hooked up) and it locked. One thing is that the fast option seems to be missing (when we enable it, we have no fast output). We need to check the serial number of CM board.

EY PLL CM board: S1102641 ALS

EY PDH CM board: S1102632 ALS

Travis, Giles, Gary, Jason, Norna, Betsy

This afternoon, Travis, Gary, and Giles finished welding in fibers to the ITMy (ITM011) and it's glass PUM.  At some point during the welding process on Wed a roll of the Test Mass was introduced.  It was noticed this morning before the final destress/annealing took place.  The team attempted a correction to alleviate ~1/2 of the roll error which was somewhat successful.  After reevaluating the tolerance for roll with Dennis and Calum it was decided to leave the roll error as is.  The Test Mass is now hanging from the fibers.

Note, the roll error observed this morning was +/- 1.2mm (~7mRad).  We determined that this roll occured between welding the 2 sides of the suspension with the masses locked down the entire time.  The PUM did not show this large roll error.  After correcting and suspending the ITMy, the roll was found to be +/- 0.75mm (~4mRad).  While the roll "tolerance" has never really been set, we attempt to get the roll error within +/- 0.2 mm because that is what we have found we are able to do in all of the previous other monolithic suspensions.

The stage 2 lower walls have been added. The bolts that go up through the optical table have all been torqued.

The stage 2 lower walls have been added. The bolts that go up through the optical table have all been torqued.

Will be baking RGA over the next week or two(?) while connected to but isolated from Y2-1

8:58-11:09 Heading to EndX/EndY to attach some signs – Justin
9:09-12:00 Working by HAM3 TCS rack – Aaron
9:20-11:15 Using West crane to fly Leak Detector over YBM – Kyle
9:40-      Going to EndY to work on Oplev/Pcal Receiver Pylon – Craig 
9:40-10:00  Heading to EndY to remove excess grout from Op-Lev pier base – Jeff
10:15-12:00 Going into the LVEA West bay area – Betsy
10:48-12:00 Going to EndX TMS Lab – Corey
11:01-      Back to the LVEA for more TCS work - Aidan
11:09-12:00 Cleaning by the Beer garden area (LVEA) - Chris
12:40-14:16 Going to EndY to do cleaning work - Karen
12:40-14:49 Going to EndX to do cleaning work – Chris
13:37-14:20 Giving a tour in the LVEA - Fred
14:15-      Heading to End Y – Jeff
14:22-14:32 Closing PT-246 at Y-mid - Kyle

I have turned up the watchdog threshold, the BS also tripped around the same time I will leave it for who ever untrips that to post the plot. 

This is the HEPI L4C WD that as Fabrice has told us we could defeat by raising the threshold, because the L4Cs are not in the loop. 

Since we are routinely defeating this watchdog, it seems like it would be much better if it didn't exist. 

Red letters are to make Rich happy.

Chris, Sheila, Alexa, Daniel,

This morning Chris rephased the ALS WFSs, and balanced the gains of the different sections.  Results were verry sensitive to the cavity alingment, so a few iterations were needed.  Then he measured the sensing matrix again several times, this also depends on the cavity alingment.  These three measurements were with as good of an alingment as we could find by hand (phase in degrees in parens for those elements where the phase was inconsistent):

With this information we zeroed out WFS B to ITMX PIT and ETMX YAW and WFS A to ITMX YAW, the elements where the phase wandered, and then inverted this. We also offloaded the WFS alingment signals to the top stage, to avoid saturating the DAC. 

Chris has also written a script that centers the WFS using the picomotors.  It is userapps/als/h1/scrpits/als_x_wfs_center.py

We have also written a wfs relieve script at userapps/als/h1/scrpits/WFS/alsWFSreleive.sh. This just relives the top stage, onto the offset of the M)_LOCK filter bank. 

We were then sucsessfull in turning on all 4 DOFs, and we turned up the gain, we estimate that we got a ugf of 1 Hz for both of the Pitch loops.  We made the attached measurement. In the left plot, the COMM noise measurement (no cavity pole removed) from monday night is the blue reference, and our measurement from tonight is in red.  The rms down to 0.1 Hz is 10Hz, still almost 30Hz down to 0.02 Hz.  We also have higher noise at 1-3 Hz, we don't know if this is caused by the changes to the WFS, or if it is just a difference in the ground motion.  Because of the earth quake we aren't able to repeat the measurement without WFS right now, but we looked at some coherences to try to understand. The top panel in the middle plot shows that the oplevs have coherence with the WFS control signals up to about 1 Hz.  We looked at some end X seismometer coherences and don't see anything (bottom panel of middle plot). The right plot shows that the oplevs do have coherence with the COMM Noise from 0.4-0.8 Hz. 

This data is saved as COMM_NOISE_April_2.xml in my COMM folder (sheila.dwyer/ALS/HIFOX/COMM)

The new ITMx monolithic welding has been successfully completed and was left suspended overnight last night.  The majority of the modal measurements have also been completed today, with the exception of the violin modes, which are proving to be trickier to measure than in previous suspensions.  We will continue with these measurements tomorrow with some different equipment.  Stay tuned for subsequent posts with IAS and modal measurement numbers.