Performance is another question but at least it is stable.  No trips of the ISI or HEPI since before 1700pdt yesterday.

(Borja)

I have continued the coil balancing work that Jeff and Arnauld did yesterday (aLog entry 13203). In these measurements I have concentrated on SR2 and redone stage M3 (with an improved balance) and tried to balance stage M2, however in trying to do so I encountered some problem as reported on the notes attached below, it is worth noticing that tunning of the UL coil on stage M2 has no effect at all on the output signals which may indicate that the coil is actually not connected.

Summary of balancing performance:

Summary of the optimum balancing Gains:

Apollo installing viewport gatevalves on H1 BSC chambers in LVEA for ionizer equipment

09:03 Nathan starting unattended laser work in the optics lab
09:12 Hugh to HAM4 to remove ameristat and unlock HEPI
09:18 end Y transitioned to laser safe
09:32 Jeff B. and Andres to HAM6, contamination control check
09:41 Travis checking on mobility experiment on west door of HAM3
09:46 Jim B. to check on SEI IOP (unexpected shutdown at 8:41)
09:47 Betsy picking up equipment in LVEA
10:13 Dave and Jim B. restarting end Y SEI, will take down end Y ISC and SUS (on same Dolphin network)
10:16 Hugh done unlocking HEPI
10:39 Dave and Jim B. restarted the mid X weather station
10:56 Sheila to IOT2L, if it has been moved into place will install light pipes
11:00 Bubba to end X to retrieve part for door removal
11:00 Jordan, Paul and Sudarsham to Y1 beam tube enclosure, accelerometer measurements
11:08 Jason and Doug to begin alignment of ITMX optical lever, Arnaud to put ITMX mirror into nominal position
11:18 SnoValley to see John W.
11:34 Paradise water delivery
11:34 starting HAM6 door removal
11:43 Peter K. to end Y to take pictures through viewport
12:03 Krishna, Eric and Jeff K. to end X to work on BRS
13:08 Christina to end X and end Y to install magnetometers
13:12 Aaron to start drilling in the old H1 PSL chiller room (WP 4777)
13:39 Paul and Jordan to end X for PEM measurements
13:57 Dan and Koji to HAM6 to install fast shutter
14:17 Gerardo, Rai and Kyle working on ionizer experiment at end Y
15:43 Fire department investigating trouble panel alarm at mid Y
16:45 Nathan supervised by Dick G. in optics lab

Maintenance tasks:
PSL chiller filled yesterday, left alone
reset HEPI overflow counters for HAM3, BS.
John W. confirmed work was done regarding this alog. I set HVE-MY:Y5_246BTORR.HIHI back to 5e-08.

WP 4776

I stopped conlog 1.3 on h1conlog at 17:26 PDT. I ran the script to create a new channel list and started conlog 2.0 on h1conlog2 with it. The database is being replicated to a read only copy on h1conlog3.

The web search interface can currently be accessed from an internal CDS machine at http://h1conlog3.

I am in the process of creating a backup of the 1.3 database.

Jeff K., Krishna V., Erik S.

Today we started with the assembly of the left arm of the vacuum can. The older flexures on the balance were damaged during transport so we replaced them with another pair Krishna had brought. We then inserted the balance into the 6-way cross and suspended it successfully. We were then adjusting masses on the balance to lower the resonance frequency close to 10 mHz. By the end of the day we got the frequency close to 20 mHz. 

Pictures of the assembly process attached in assembly order!

Will resume attended rough pumping of Vertex, XBM and YBM combined volumes tomorrow 

Alexa, Sheila

We saw that there was no signal on the PSL periscope PD, so we entered the PSL to investigate.  There is currently 170mW of light entering the periscope, and 0.7uW incident on the PD.  We measured the voltage from the PD using an osciliscope, it has a 13 mV offset and 4 mV of signal.  (both negative) This gives 0.38A/W, (we did not change the gain switch, so the gain setting should still be 15kOhms), and the pick off ratio (power on PD/power into HAM1) is 0.004.  These are not so different from the measurement Paul reported in alog 9865  We will stick with the old calibration which was made with more light on the diode.

We did not finish checking the calibration of this PD because there is also a problem with beckhoff.  Everything on corner chassis 3, 4, 5, and 6 is NO_COMM.  The problem with beckhoff was fixed by unplugging and reconnecting the cable between Corner Chassis 2+3, which could be a bad cable that needs to be replaced.

[Dan Koji]

A first fast shutter was placed at the approximate location on the HAM6 table. The cable has been connected to the shutter.
The feedthru end of the cable is waiting for replacement of a 2.75" feedthru flange. This flange is D3-3 according to D1002877.

The table space is really tight. The space for the shutter was just barely OK to place it behind OM3. It yet needs precise aligment.
The path for the (expected) reflected beam from the shutter was cleared by moving the beam dump for ASAIR beam diverter

The golden beam dump was installed at the edge of the table. This was realized by moving the cable post for the beam diverter.

Discussions with MIT (RichM) and looking closer at the very controllers & filters I plotted showed the problem.

While the developed controller I showed in the SEI Log, looked like it should not have been terrible at dealing with the potential instability at 8hz, the filter I posted in the LHO alog, was in fact a design unable to deal with this problem with strong peaking and marginal phase room at 8hz.  Once I realized these two views of the ETMY controller could not be the same, I knew somewhere the problem was twisted.  So I painstakingly went through all the filter design steps and sure enough, the design was there but was not saved correctly or prepared properly.  The Blue traces are the new X controller in the attached for ETMY while the Red traces are from the ITMX which is how ETMY appeared before.

There is of course no free lunch and if I understand and can explain (mostly for my own benefit).  The large phase bump in the 8ish Hz area pulls the controller away from instability and the design inherently has less gain peaking (maybe that is the same thing.)  On the other hand, if the zero in the plant (which can move around) moves away from this design point and/or the designer is too aggressive at matching the plant, the controller will develop something... (gain peaking?)

At the moment, ETMY is running under full Guardian Management in FULLY_ISOLATED.  Don't want to get ahead of myself but it has been almost 15 minutes now and Rai & Gerardo are still down there working on the chamber.  I have had one previous trip of the ISI for L4Cs but HEPI did not trip.  So, at least we are in a new epoch for BSC10 HEPI.

Summary : We tested charging/deionizing of the unsuspended, isolated ITMY (Corning ETM02) with a new electrometer, the Alphalab Ultrastable Surface DC Voltmeter. We first measured the field at the HR surface of the optic interleaving a series of timed deionization runs with the TopGun Deionizer.  Next we applied and ripped FirstContact, and repeated measurements/TopGun nitrogen deionization. The deionization process appeared to take several minutes, having some effect out to nine minutes - however we have to repeat the measurement to assess charge on the barrel and AR optic surface (G. Moreno, N. Robertson, M. Landry, with C. Torrie and R. Abbott).

Details :

We set ETM02 (recently employed in BSC8/1 as the pilot ITMY for single-arm/HIFO experiments) upright on a teflon V-block in a cleanroom of the west bay of the LVEA ("fiber welding cleanroom"). We made measurements of the electric field 1" from the center of HR surface of the optic, and four measurements halfway between the center and the limb of the optic (right, top, left, bottom). Initially we simply applied the TopGun nitrogen in a series of 3 minute applications.  Later we applied FirstContact, let it dry overnight, and the pulled (with concurrent TopGun dionization), and made more field measurements interleaved with de-charging.  The data are below.

All values in negative kiloVolts (-kV) as read from the hand-held meter, unless otherwise signed positive. Field values in kV/m can be obtained by scaling by ~30X.

where

Vc = raw voltage (kV) 1" above center of HR surface
Vr = raw voltage (kV) 1" above center-right (i.e. at a radius of +34cm/2, 0 degrees rotation angle) of HR surface
Vt = raw voltage (kV) 1" above center-top (i.e. at a radius of +34cm/2, 90 degrees rotation angle) of HR surface
Vl = raw voltage (kV) 1" above center-left (i.e. at a radius of +34cm/2, 180 degrees rotation angle) of HR surface
Vb = raw voltage (kV) 1" above center-bottom (i.e. at a radius of +34cm/2, 270 degrees rotation angle) of HR surface

and trial data were taken under the following conditions:

Trial 1 - Initial measure of electric field, HR side of optic, prior to application of FirstContact (FC), or TopGun deionizer (TG)
Trial 2 - same as trial 1, but 24 hours later, to see if there is some discharge in air (there is, ~25% lower than trial 1)
Trial 3 - After 3 min of TG deionization
Trial 4 - After 3 min of additional TG (6 min total)
Trial 5 - After 3 min of additional TG (9 min total)
Trial 6 - No additional TG, but after 3h delay
Trial 7 - FirstContact applied, then removed in a 2 min pull, with concurrent TG (2 min), plus additional 2 min TG thereafter
Trial 8 - After 2 min of additional TG (6 min total)
Trial 9 - After 3 min of additional TG (9 min total)

Individual measurements of the field could take 3-4 minutes to stabilize in the Voltmeter, i.e. values read out on the hand-held unit may have initially read hundreds of volts, falling and stabilizing to a seemingly stable number over the 3-4 minute time frame.

We wil repeat these measurements and include barrel and AR surface tests.  However, in consultation with C. Torrie and R. Abbott, and in order to be conservative in closing BSCs 1, 3 and 9, we opted to extend nominal few-minute TopGun blowing times for test masses and reaction masses to nine minutes total, i.e. 4.5 min for a given test mass HR face, 4.5 min for the AR gap, 4.5 min for the reaction mass upstream face, 4.5 min for the gap. We cycled between surfaces and gap in 1 minute intervals, summing to 9 min per optic.

While doing cabling for HAM6 in the CER, noticed that the following cables for ISCT1 in ISC-C2 were plugged in backwards. Swapped the following at the EtherCAT Corner 5 Chassis. Cables are connected as listed below and match the pull list E12000408.

Cable_ISC_328 connected to Port 9 (DC PD's ISCT1)
Cable_ISC_326 connected to Port 10 (Auxiliary ISCT1)

Filiberto Clara

I have updated the MEDM screens which are snapshotted and displayed on the web page:

https://lhocds.ligo-wa.caltech.edu/screens/

• OSEM MEDM was updated and completed, sized to fit
• old IOP watchdog screen replaced with new SWWD FOM screen
• CDS OVERVIEW (Small) sized to fit

Diagnostic breadboard scans were executed; these are to measure the frequency noise, beam pointing,
mode content and relative power noise.

Some notes in passing:
 - The higher mode content of the frontend laser looks okay.
 - Autoalignment did not go green as expected, I will have to sort this out after reading the manual.
 - The beam pointing seems higher than the requirement but this could be because the calibration is out (plus my operating error).
 - The relative power noise is higher than the requirement, assuming the calibration is correct.
 

Reference Cavity Re-alignment
=============================

The reference cavity transmission has steadily degraded over time from ~1.1V a month ago down to the ~0.4V when Jeff reported the problem to me.  A quick look at the alignment using only the periscope adjustments, did not make things any better and in fact I made it a little worse, leaving the transmission at ~0.22V (as displayed on the MEDM screen).  That indicated that either the alignment into the AOM was off or the RF level to the AOM was off.

Measured RF on oscilloscope, with 50 ohm input.
freq = 79.4 MHz
peak-to-peak amplitude = 21.66 V
Vrms = 7.965 V

So the RF level into the AOM is 1.27 W.  This is about the right level for maximum diffraction efficiency.  Note that the maximum RF power into the AOM is 1.3 W.

zero reading on power meter = 2.7 mW, power meter used is the Ophir thermal calorimeter
no measurements have been corrected unless otherwise noted
power incident on AOM, measured after PBS = 57 - 62 mW
power incident on 21.5 MHz EOM = 21 - 23 mW
this represents a double pass efficiency of ~ 22/59.5 = 37%
or a single pass diffraction efficiency of ~61% (Sqrt[37%])

After adjusting mostly the height of the AOM, the power before the 21.5 MHz EOM was 26 mW or 66% single pass diffraction
efficiency, further tweaks to the height resulted in 34 mW or a single pass diffraction efficiency of ~76%

Tweaked alignment into reference cavity using the periscope - mostly height adjustments; measured reference cavity transmission is ~710 mV on DMM, ~1.16V on MEDM display.  This is as good as the value from over a month ago.

Since we are pumping down the volume, we decided to postpone restarting the models. So the mission is incomplete.

If one wants to change the ASC or LSC model in the meantime, please notify me.

Completed stripping the Ameristat from the HEPIs and unlocking the platform at 1015pdt.  Closed the HEPI loops with no difficulty.

Attached at spectra from overnight (HELI Locked) compared to after unlocking; and, comparing after unlocking to having the position loops closed.

Comparing the three states, basically it depends, some frequencies better, others, not so much.

The Mid-X weather station, which died Saturday evening, was restarted by power-cycling the Comtrol box and the weather station.  The EPICS IOC for the weather station was restarted and the weather is now being reported properly. No equipment needed to be replaced.

[Jeff Arnaud]

Tonight we balanced the coils of the lower stages of MC2 SRM and SR2. The MC2 notes attached are explaining the procedure in detail. Below is summarized the ASD ratio after/before the exercise for each suspension and each level.
For some reason M3 stage of SR2 was harder to balance than the other ones, so we gave up on it for now and will come back to it later.

And the gains which were found optimum for each coils

Measurements will be running overnight to measure the cross couplings transfer functions for SR2 SRM and MC2

This plot is interesting.  It seems the only moderately pronounced peak in the horizontal ground spectrum wanders, seen from 8 to 11hz changing quite rapidly.

The attached plot's current traces are with HEPI loops closed and the ISI Damped.  While the middle graph shows all four local IPSs have the strong 8hz peak (the dashed REFs are with the HEPI loops open), the peak only shows in the X & Y and not the RZ cartesian traces (top graph).  Also, note the bottom graph where the ground sensor pretty much has nothing at 8hz but does have a minor peak just above 9hz that is also peaking up in the local sensors.

The second plot shows just the ground Seismometer with X & Y traces from last night (Dashed) and the others from this morning. The peaks in that area come and go and wander around so it may or may not be a problem or just a red herring (are those edible?)