PeterK, JeffB, RickS

This morning, Peter set irises to mark the beam pointing in advance of the water line work.

We then installed stops to register the position of the Front End baseplate, removed the pump fibers, moved the Front End box to the edge of the table,  removed the 35-W amplifier from the Front End box, and replaced the "quick connect" water fittings with 8 mm push-to-connect tubing fittings (see attached photos).

We did a pressure test with the 35-W head plumbed in the new configuration but outside the Front End box to check for leaks before re-installing it and moving the Front End box back into location.

We also removed all the flow-regulating valves from the supply-side water manifold for the three circuits: 35-W amp, 70-W amp, and high-power shutter.  We moved the flow meters to the return-side manifold so that they would respond to a leak in the water path by shutting down the chiller before exhausting the water supply.

Initial flows were: 1.3 lpm, 2.7 lpm, and 1.4 lpm for the three paths.  We then installed a 3-4 ft. section of 6 mm (OD) tubing in the 70-W amp path.  The resulting flows were: 1.4, 1.9, and 1.4 lpm.  So we added about 40 ft of 8 mm tubing (we didn't have any more 6 mm tubing) to get flows close to the 1.5 lpm target: 1.4 lpm, 1.6 lpm, 1.5 lpm (see attached photo).  Note that the "pwrmtr" signal is really for the HP shutter).

Note that we have not yet modified the chiller configuration to reduce the laser-end water pressures, now about 70 psi on the supply side and 50 psi on the return side, by throttling the chiller output to reduce the pressure drop across the heat exchanger on the return-side path to the reservoir.  We plan to do that later in the week.  We are waiting on a part that is schedule to arrive today or tomorrow.

Our detailed task list is also attached for future reference.

With PSL being down this morning replace and cleanup fiber cabling in the MSR and CER. This work effected both the Safety and Slow Controls systems.

In preparation for ISCT1 being moved, field cabling was disconnected this morning.

I have adjusted the tuning parameters at EX, namely the Proportional and Integral on the Face-Bypass Dampers to try and slow the temperature swings. Although we are still maintaining the desired temperature, the swings are apparently to severe for the BRS. 

Carlos, Dave

We have installed the new computer in the rack slot formerly used by h1auxscript0. It is unclear that this aux machine was actually doing anything, so we may leave it out of the rack for now. The new video server will be called h1digivideo3 and run Debian9.

The updated mode-matching solution to account for the noise eater alog(44783) assumed a waist at the coupler of 750um (because that was in the thorlabs documnentation recommended). However a measurement indicates a waist of 500um out of the coupler.

I adjusted the solution SHGtoFiberAM.pdf alog(44783) to move the  ROC75 lens 6cm closer to the SHG the ROC200 lens 1-2 cm further away from the SHG and the fiber coupler 10 cm further away from the SHG to get a waist of 550um.

To get a waist of 500um would take a relatively major path rearrangement and with the vent only hours away it was a little risky to do it now, I will fine tune after the vent and hopefully the proper solution will be significantly above 85%. 

Turned ON air compressors in chiller yard for instrument air, QDP80 is ON, and purge air skid is ON.

Hard closed GV 1,2 this morning and then vented HAM6 (~45 min. vent). Dew point measured -45degC just before valving in purge air.

I've put in a temporary bypass for HAM6. We'll bypass others as the vent progresses.

Bypass will expire:

Tue Nov 13 08:36:07 PST 2018

For channel(s):

    H0:VAC-LX_Y0_PT110_MOD1_PRESS_TORR

TITLE: 11/12 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    Wind: 8mph Gusts, 6mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.30 μm/s
QUICK SUMMARY:

15:00 Peter out to PSL

15:17 Chris S out to LVEA to fix scaffold

15:18 Cheryl out to PSL

15:40 Cleaning crew out to LVEA

16:16 Chris S out

In prep for this weeks vented volumes followed M1300464 and shut down High Voltage and other system of concer.

EY

Ring Heater switched off

+-430V  ESD supplies shut off

Pico Motors disabled.

Corner station

Ring Heaters for ITMs and SR3 where shut off.  ITMX was already off.

Fast shutter controller HV disabled chassis powered down Power supply off

PZT unit powered down PZT power supply off.

ESD Power supply off

All pico motors confirmed to be or placed in disabled.

OPO TEC servo turned to the off position.

The LVEA has transitioned to LASER SAFE.

    This is under work permit #7934, and facilitates the venting of the corner station.

n.b.
  

    
 The PSL and ALS light pipes are locked and tagged out.
    
 Both TCS CO2 lasers are on.  No work is to take place on either TCS or HWS tables unless barriers are set up.
    
 The squeezer laser is off.  The power supply key is inside the table enclosure and the laser shutter is closed.
  

    Verification that no PSL light is entering the vacuum system is attached in Transition.png

On site now.  Will head out to lock HAM 6 HEPI and disable the ISI to disconnect cables from feedthrus.  Will comment here when complete.

Georgia mentioned yesterday that the fast shutter lockloss guardian was failing it's check.  We saw this again today, after we powered up and then reduced the power with the interferometer still locked. 

The problem here was that the shutter lockloss check guardian watches the transmitted arm powers, and if they go above a threshold it watches for the shutter to fire when we loose lock.  We went below this threshold when we reduced the power again to do OMC scans, which caused the LOCKLOSS_SHUTTER_CHECK guardian to go into the failed state, which it stays in until a human intervenes by taking it to init. 

The shutter has passed it's test a few times today.  

We observed some improvement with larger PD current yesterday. It was not clear to us why. There is some chance that a calibration issue is fooling us, but at the low frequencies we were looking at the calibration should only depend on the actuator.

Either way, to get to the bottom of this, we revisited the whitening of those PDs.

Currently, we are using 10mAmp per diode in regular operation. If the violins are smaller (as the were yesterday) we can increase the DARM offset to operate at about 15mAmp per diode, but that becomes a problem when the violin modes are high.

Attached is a plot of the whitening situation of out OMC DCPDs in full lock, with about 14mAmp per photo diode.

ndsope inset top: ADC signed of the photo diode
ndsope inset bottom: photo current on the photo diode
dtt red: PD signal in cts ADC (which is loop gain suppressed, hence the dip at 30Hz amd the peak at 100Hz)
dtt blue: dark noise
dtt green: possible option with current whitening filters: additionally engage a 2nd whitening stage plus the low-pass. Reduce the DARM offset by 3.2dB to get the violin mode peaks back down where they were.

It would be worth testing the green configuration, just to exclude that we have some load-dependent dark noise after the whitening stages.

Fil Marc Daniel

We modified the spare CM board (s/n S1102622) according to E1800338 and swapped it with the existing one (s/n S1102621). This modification includes low pass filters for the DAQ readbacks, and a frequency change in the first two boost stages to 10Hz/500Hz.

The figure shows spectra from the 4 angular IMC WFS DC channels with labeled peaks. Eight of the peaks between 80 and 1000 Hz are from optics or structures on the PSL table, two were from IOT2 and four haven’t been identified. The unidentified peaks were not excited by our PSL injections, even the global ones. It is possible that they are associated with structures that weren’t excited on IOT2 or in HAM2, or they may be associated with structures on the PSL table that we weren’t able to excite.

The identified sources are table resonances, periscope resonances and optic mount resonances. All optics that produced peaks in the spectrum were downstream of the PMC and were mirrors rather than through-optics like lenses, as would be expected.

The figure also shows the location of the sources in the PSL, as well as samples of the bowing and tapping data used to make the identifications.

Robert, Craig