This morning I performed the weekly PSL FAMIS tasks.

HPO Pump Diode Current Adjust (FAMIS 8447)

With the ISS OFF, I adjusted the HPO pump diode operating currents; this week required a larger increase than usual from all 4 HPO DBs, this is summarized in the below table.  As usual, I attach a screenshot of the PSL Beckhoff main screen for future reference.

I did not adjust the operating temperatures of the DBs.  The HPO is now outputting 155.0 W and the ISS is back ON.  This completes FAMIS 8447.

PSL Power Watchdog Reset (FAMIS 3675)

I reset both PSL power watchdogs at 17:55 UTC (9:55 PST).  This completes FAMIS 3675.

Apparent LASER trip (10/31) and corresponding aLog. Environmental data seems to have quieted. An incursion by Peter, yesterday, is also apparent. All other data appears to be normal.

I'll detail the rebalancing after I review the previous payload to document changes--Exec Summ: removed many kgs.

S Cooper, S Dwyer, J Kissel

Sam has been looking into what trips in what order durring large earthquakes, and one thing he has run into is that we have different RMS thresholds for tripping different suspensions, meaning that for some optics R0 will trip while M0 might not for a particular EQ.  I have gone through the QUADS and set the RMS MAX to be the larger setting where settings differed between optics. SDF screenshot showing changes is attached.

Kyle R., Rakesh K. 

Today we vented the ion pump, decoupled the KF flexline which had connected the 55 L/s ion pump to CP2's 1.5" pump port and then reconfigured the fittings and added a small turbo to the ion pump assembly.  We will make the connection of the ion pump assembly to CP2's pump port valve tomorrow.  For tonight, we pumped down the IP side of the 1.5" pump port isolation valve via the leak detector and will leave it connected, under vacuum and turned off.  The leak detector is hose-clamped to a fixed post to prevent it from being moved, and thus, straining the connection to the pump port isolation valve.  

Today:

• IM4 pitch adjusted
  • required removing the IM4 SiC baffle
  • required loosening both lower EQ stop brackets to allow the inner SiC baffle to clear the EQ stop brackets
  • the pitch adjustment screw/sleeve was turned less than 1/2 of a turn
  • current IM4 pitch, with zero alignment bias, is -124urad
  • loosened blade attachment blocks to correct a ~-1100urad yaw with zero alignment slider
  • current IM4 yaw, with zero alignment bias, is -144urad
• IM2 yaw adjusted
  • loosened blade attachment blocks to correct the 2000 slider drive in yaw
  • IM2 yaw, with zero alignment bias, was ~-1500urad
  • current IM2 yaw, with zero alignment bias, is -36urad
• IMC irises placed in HAM2 and HAM3
• beam from PSL aligned to the IMC with the PZT
• IMC is flashing

Tomorrow:

• brief start to the day with laser safe - still some irises to place downstream of the IMC
• once that's done, will need the beam to continue the IO alignment

- Cheryl JeffK, JeffB, PeterK

TITLE: 11/07 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:
LOG:

17:45 Kissel to HAM2, Hugh to HAM2
18:00 Cheryl to HAM2, Hugh to HAM4
18:30 Jason, Betsy, Travis to Biergarten
19:00 Terry to sqz
13:00 Travis to Biergarten
21:45 Cheryl to HAM2, Peter to PSL
22:00 Terry to sqz
22:15 HFD on site for quarterly tour
22:45 Kyle to LVEA
22:45 Peter to LVEA

In preparation for installing the new DLC coated BS elliptical baffles, today I removed the old Super8 coated elliptical baffles from the BS structure.  I also installed the new DLC coated BS EQ stops and mounts.  The hunt for a few of the new baffle mounting parts continues.  

After some digging for lost functions, I was able to run and collect data for the matlab long ISI transfer functions. Attached plots are the actuator to gs-13s most recent tf (first plot) and the previous 2014 in air HEPI locked tf. I don't see any evidence at this point that the baffles on HAM2 have affected the plant much. There are a couple little wobbles at 17 and 24 hz, but I think those are both from HEPI locked, as those feature are present in both tfs, and are huge in the CPS measurements (not pictured). The poor high frequency coherence is probably due to purge air, I'll probably want to do another tf during pump down.

I've updated the HAM-ISI model in the repo and it is ready for installation - this continues the BSC update from last week, which Dave installed last Tuesday.

recall- This change will update the HAM-ISI watchdog to make the ISI more robust during earthquakes. We have changed the model to increase the hold-the-damping-on-even-if-stuff-is-saturating time from 3 to 60 seconds.

The updated model and watchdog medm screen is in the userapps repo at SVN revision 16422

Installation instructions and more technical details are in technical note T1700481.

The approved ECR is E1700367

and the FRS is 9309
 

I've not pulled work permits.

-Brian

As mentioned here, the PMC transmission is currently lower than usual (and lower than during O2).  In preparation for the IO IMC bypass and CS alignment to take place later this week, I tweaked the beam alignment into the PMC to try to recover as much power as possible.  Unfortunately, I wasn't able to recover much power; with the ISS ON and diffracting ~3%, the PMC is transmitting 48.8 W, versus the 48.7 W it was transmitting before I started.  The likely reason for this is bad mode matching into the PMC due to the recent NPRO swap (which could change the mode content of the PSL enough to alter the required PMC mode matching scheme).  We are likely to stay in this configuration until the HPO is decommissioned and the 70W amplifier installed (currently scheduled for late January/early February 2018), unless there is an overwhelming need to improve the PMC transmitted power.

No obvious errors. Just had to select run.

Restarted. Screenshot attached.

1) Resonances of the ITMX elliptical baffle match peaks in DARM. Several peaks in DARM, (e.g 70 and 106 Hz), were thought to be due to the elliptical baffles, either or both ITMX and ITMY baffles. This is because, for different vibration injections, the amplitude of these peaks in DARM were best explained by the vibration level at ST0 of BSC2, and these baffles hang from this stage of the ISI ( https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=26016, https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=31886 ).  To make sure that this identification was correct, I measured the elliptical baffle resonances with an in-chamber accelerometer while tapping on them. Figure 1 shows that resonances of the ITMX elliptical baffle match the DARM peaks, but the ITMY baffle resonances do not. Betsy will check to see if the ITMX baffle down-tube is misaligned when the upgraded baffle is installed. 

2) Possible sources of scattering in BS chamber. Follow-up PEM injections showed that shaking the walls of BSC2 produced noise in DARM (https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=39121 ).

One long term concern in BSC2 is the TCS mirror 2 and its support structure that is attached to the BSC2 wall: https://alog.ligo-wa.caltech.edu/aLOG/uploads/9564_20140126161227_Figure2-ITMXcompensationPlate.pdf .

Scattering associated with the mirror could either be from the support region surrounding the mirror or from the nozzle and flange holding the TCS ports, visible in the mirror (see Figure 2 and https://alog.ligo-wa.caltech.edu/aLOG/uploads/9564_20140126161227_Figure2-ITMXcompensationPlate.pdf ). The region around the mirror could be baffled and the port could be baffled. I talked to Steven about the possibility of a port baffle that might also be useful at the P-Cal transmitter and receiver ports.

Another mitigation possibility is to damp the motion of the mirror. I tried a very simple method illustrated in Figure 3 that seems to have reduced the Q’s of some of the resonances by 2 or 3. I think we could do a lot better by wrapping the struts with more material.

A second possible source of the scattering noise are the BS chamber walls themselves, which are nearly normal to wide angle scattering from the beam spot as illustrated in Figure 3. 

A final possibility is the elliptical baffle: I wasn’t able to eliminate this possibility because in the 14-17.5 Hz band we haven’t made strong enough injections with HEPI to exclude ST0 (discussed here: https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=39121).

3) Scattering at P-Cal ports. Nothing new to report beyond https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=39121, except that I discussed port baffle design with Stephen Appert.

4) HAM1-HAM2 septum not shielded from spot on beam splitter

Figure 4 shows that the HAM1-2 septum is visible from the BS through the structures on HAM2. The septum is a concern because of its high reflectivity and the fact that it is not seismically isolated like the reflectors on HAM2. The baffles are not yet all installed on HAM2, but I think the baffles will leave the upper regions of the HAM1-2 septum exposed to the BS. There is not an equivalent exposure of the HAM5-6 septum because the central part of the MC baffle in front of HAM5 remains in place, while the central part of the MC baffle in front of HAM2 has been removed.

5) “Temporary” floors should probably be removed for scattering reasons. The floors placed inside the chambers for working are sometimes left in place. Figure 5 shows that they may create scattering paths and should probably not be stored in place. I think Betsy was already planning to do this for charge imaging and other reasons.