Over the last week we have noticed an anomalous peak in the amplitude spectrum of various sensors on ETMX-ISI, reminiscent of the 0.6Hz peak on HAM 2(?) back when

Looking more closely it seems to be mostly showing up on  a few of the CPS channels, St1-H1, ST2-H2 and H3, see the attached screen shot. This data is with the loops on

J. Kissel, J. Warner, C. Vorvick

After Cheryl / Sheila / Hugh made another pass at torquing down IM cage bolts and applying viton between their baffles and cage (LHO aLOG 39654), Jim and I measured the new cage response with the B&K hammer / accelerometer system (LHO aLOG 39682). 

Attached are the results.

The cages now look *much* more consistent with each other. Sadly, it appears that the viton only effectively damps the transverse mode of the cage. However, the longitudinal direction's Qs are still not *really* high, and the frequency (now just one! yay!) is still above ~150 Hz, i.e. in the "safe" region for ISI control. 

Note, that this was taken before Cheryl's final battle with the IM3 cage (see LHO aLOG 39702), which she now believes has been resolved. Before that change (i.e. this data set), IM3 looked good and consistent with the other cages (see attached), so we can imagine it only has gotten better / more consistent with others. Thus, we won't bother to re-hammer unless someone strongly wishes it.

 
New data has been committed to the svn here:
/ligo/svncommon/SusSVN/sus/trunk/HAUX/H1/
    IM1/BandK/2017-12-07_H1SUSIM1_X_LongExc_Xresp.txt
    IM1/BandK/2017-12-07_H1SUSIM1_Y_TransExc_Yresp.txt
    IM2/BandK/2017-12-07_H1SUSIM2_X_LongExc_Xresp.txt
    IM2/BandK/2017-12-07_H1SUSIM2_Y_TransExc_Yresp.txt
    IM3/BandK/2017-12-07_H1SUSIM3_X_LongExc_Xresp.txt
    IM3/BandK/2017-12-07_H1SUSIM3_Y_TransExc_Yresp.txt
    IM4/BandK/2017-12-07_H1SUSIM4_X_LongExc_Xresp.txt
    IM4/BandK/2017-12-07_H1SUSIM4_Y_TransExc_Yresp.txt

Data may be processed with the following scripts:
/ligo/svncommon/SusSVN/sus/trunk/HAUX/Common/MatlabTools/
    haux_bandk_datalist.m
    plotHAUX_bandktfs.m

J. Kissel

I've processed the B&K measurements taken of the ITM elliptical baffles (see LHO aLOG 39678). 

These baffles are under suspicion after Robert found they couple into DARM (see LHO aLOG 39290).

They have since been rebuilt peppered with viton washers (see red lines in D1101806), and this data is *after* that reassembly, while the baffle was fully suspended.

Results, raw data, and script to plot it attached.

• the IMC is flashing and the beam is through the IO Faraday
• I had to align from the PSL twice today, due to finding the beam on the MC1 iris was off in yaw about half way through the day (plot attached)
• HAM2 tool stock has dwindled, so it took a while find a short allen key that I could use on the bottom left IM3 OSEM (clearance issues with MC3)
• there was significant fringing at times during the day, that made alignment a challenge, and this appears to be due to ground/beam tube motion
• IM3 needs a major realignment, and while this is going well, I am still working on getting the beam aligned to where it needs to be, and at the same time, getting all of the OSEMs centered enough that I can damp the optic
• I adjusted, for the first time, the pitch of IM3, and found that I could easily turn the bolt under the optic that controls the pitch
• I should not have been able to easily adjust that bolt, since that bolt has a collar that is supposed to be tightened to secure the bolt in place
• my finding today suggests that that bolt has not been secured with the collar for a while, so likely it's been loose since before O1
• chalk this up to another way the alignment of IM3 could have changed while the chamber is under vacuum, for example, during an ISI trip (shaking)
• I'll attempt to tighten the collar tomorrow without taking the baffle/Viton off of the front of the IM3 cage, but if I can't, I'll have to take the baffle and Viton off to access the locking collar

More details coming, but Fil, Gerardo and I spent most of today rebuilding the ITM ESD feesthru connectors to the latest rev.  This involved pulling it from the feedthru on the inside of the chamber port, cut the connector off the 5-way cable, strip and recrimp pins, and reassemble inti a new connector. We had a few failed attempts on the ITMY set but finally figured it out. 

We also found the 5th (LL quadrant) pin at the CP on ITMX not well seated in it's connector which caused us some grief. We eventually just squeezed the inner pin to make it work since we cannot fix this in any other way. The continuity checks then passed.  

TBC...

I had a little time to investigate the seemingly inadequate purge-air issue after the in-chamber folks were done for the evening and all of the soft covers were on.  Nothing definitive was determined but perhaps one clue was added.  I'll need to have a second person to confirm (one in LVEA and one at the Kobelco) but tonight it seems that the frequency of "low flow" is greater than the drying tower switching frequency.  If so, my original observation was wrong.  

For tonight, I increased the pressure setpoint at which the compressor loads from 80 psi to 90 psi..  This will only help if the issue isn't drying tower dependent.  Chandra and I should be able to investigate tomorrow but we may need to shut off the system.  

As an aside, I noticed that none of the lights are working on the HAM1/HAM2 or HAM3 clean rooms?  Both appear to be plugged in and, for the case of the HAM3 clean room, the breaker isn't tripped.   

ECR1700056, WP7245

Hugh, Jim, Rich M, Dave:

I have ported the perl scripts storeCartBiasTargets.pl, setCartBiasSetpoints.pl to new python scripts (storeCartBiasTargets.py, setCartBiasSetpoints.py). The new scripts take exactly the same arguments as the original scripts, so no changes to the calling systems are needed.

Hugh and Jim allowed me to test my code on H1 ISI ITMY ST1 this afternoon.

In the old system, the 'set' command was called from MEDM (ISI_CUST_CHAMBER_ST1_BIAS.adl) within an xterm calling a wrapper shell script, while the 'store' command was called directly. The xterm allowed any errors from the script to be displayed.

In the new system, both commands are called via an xterm window calling a wrapper shell script (storeCartBiasTargetsWrapper.sh was created for this purpose). The new scripts perform more error checking and user feedback which is shown in the xterm.

After testing on H1 ISI ITMY ST1, I restored all the settings back to their original values (using a ramp time of 5 seconds). The new code is now ready for rollout on all ISI systems.

J. Kissel, S. Pai

I've processed the results of using the B&K hammer accelerometer system to characterize the resonances of the support structure for the TCS Steering Mirrors in BSC2 (SM 2, D1101851). These have been of concern after Robert identified them as potential scattered light sources in LHO aLOG 39290. Since, they've had standard SUS vibration absorbers (D1002424) installed to help reduce the Q of their resonant features (see preliminary testing at T1700535).

We have no before-vibration-absorber data other than Robert's spectrograms, but I attach the new results with vibration absorbers installed.

I also attach a crude screenshot comparing these results against Robert's spectrograms, and the resonant features roughly line up. #sanitycheck

The results show that, while the majority of the resonant features *above* 30 Hz have a nice low Q, there remains a feature at 25.62 Hz (for TCSY's mirror) and 20.88 Hz (for TCSX's mirror) that is still particularly high Q. 

Edit -- I attach a zoom of these ~25 Hz resonances, as well as the raw data and a script written to analyze it.

Cheryl & Ed are continuing IO work at HAM2 past 16:00. 

• ITMy had its "pizza crust" FirstContact painted on the perimeter of the FC spray sheet that was applied last week.
• CPy had its FC painted on.
• CPx had its FC painted on.
• ITMy PUM cable ground loop fixed.  Cable was routed through a pinch point in the Top Mass.  The cable was moved out of the pinch point and the short was alleviated.
• BS Top Mass ground loop checks were started, but aborted until tomorrow until better access to the outside of the feedthrough can be established.

For tomorrow, we will need to swing the ITMy ACB back into its nominal location such that we can recover our only ACB swing back wedge (the second wedge we borrowed from LLO was returned earlier this month).  Swing back ITMx ACB and apply spray FC and "pizza crust".  Finish out BS ground loop checks and start ITMx ground loop checks.

I wrote a python script (userapps/release/cds/common/scripts/delete_daq_empty_files.py) which will delete any zero sized gwf or md5 files in the current directory. It defaults to 'dry run' mode (lists files which would have been deleted).

I ran this on h1fw1's 11970 and 11969 directories for full, second and minute files to clean the file system up after Sunday's disk filling event.

This morning I completed the weekly PSL FAMIS tasks.

HPO Pump Diode Current Adjust (FAMIS 8452)

With the ISS OFF, I adjusted the operating current of the HPO DBs.  The changes are summarized in the below table, I also attached 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 155.4 W and the ISS is back ON.  This completes FAMIS 8452.

PSL Power Watchdog Reset (FAMIS 4023)

I reset both PSL power watchdogs at 16:55 UTC (8:55 PST).  This completes FAMIS 4023.

The LVEA has transitioned to LASER HAZARD.

Vacuumed in HAM2, using this combination of vaccum hoses:

• tiger vac
• vacuum hose covered in a new clean C3 cover
• adaptor that attaches to about 30 inches of plastic hose (~1.2inch, wiped outside and IPA run through the inside)
• Kapton tub

The Kapton tube was class-A, so I used it to vacuum horizontal surfaces in MC3, MC1, PR3, IM1, and IM3 cages, and I did use it in contact with the metal.

I kept close track of the space under the +Y MC3 blade spring, and from this test area I can see that larger particulate are picked up by the vacuum, but smaller particulate are not, and when I wipe with a IPA wipe, the small particulate are removed.  Picture attached.

I put IM1 on EQ stops and used the vacuum to remove a large particle on the upper portion of the face of IM1, and this was successful without any contact between the optic and the Kapton tube.

I used the same technique to remove large particulate from the MC REFL periscope 2 lower mirror, which was very contaminated.  Not all of the particulate that I could see would come off of the optic, so some may be scratches that have been present since install.

Given my conclusion that vacuuming leaves small particulate, I wiped over all of the surfaces that I could reach in HAM2 from both the West and East doors.

PRM stage M2 has OSEM flags on the HR side of the tower that do not go into OSEMS, and the -Y flag has shifted out of place, and will need to be restored.

The really big story is that IM1, IM2, and IM3 shifted in alignment between 50 and 1500urad, and I have only one explanation for this, which is that the 4 8/32 bolts that hold the top plate to the side plates are loose, and will need to be tightened.

These bolts are covered by the brackets that hold the blade spring EQ stops at the top of the tower, so the brackets will need to come off to give access to the remaining 4 loose bolts.

This also reveals that the root cause of the shift I saw in IM3 after the B&K, a shift  I recreated myself by tapping with a dog clamp on the top plate, are these 4 hidden loose bolts.

(Peter K, Gerardo M)

All dog clamps holding the OFI spacer were re-torqued, due to finding one dog clamp loose.
AOSEMs were set on brackets and positioned to be close to center (per MEDM screen), all fastening components were tighten, set screws and adjustment collar screw, to hold them in place.
Next step is to run a transfer function to determine damping.