Betsy, Slawek, Sebastien

The remaining AMDs (AMD3 and AMD4) have been installed in the ITMX and ITMY test masses. The install went well, and the epoxy curing passed the dynamic test. Tomorrow we will remove the jigs from the chambers, which should be straightforward. We will also post a detailed log about the AMDs exact locations on the flats+pictures.

J. Kissel, C. Vorvick, B. Weaver

In prep for closeout of HAM4 after swapping out the SR2 Scrapper Baffle (see LHO aLOG 41768), Cheryl and Betsy remeasured the standard suite of SR2 top-mass transfer functions, and I took a set of ASDs for all the OSEMs hunting for ground loops.

Transfer functions reveal the dynamics are still free-and-clear (even with the large Yaw offset needed to steer the SR3 beam to SR2, as has been needed after the Sep-Dec 2017 incursion), and ASDs suggest that there are no ground-loops on the suspension electronics.

Team SUS is GO for HAM4 door closure.

Raw data lives here:
/ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SR2/SAGM1/Data
2018-05-02_1655_H1SUSSR2_M1_WhiteNoise_L_0p01to50Hz.xml
2018-05-02_1655_H1SUSSR2_M1_WhiteNoise_P_0p01to50Hz.xml
2018-05-02_1655_H1SUSSR2_M1_WhiteNoise_R_0p01to50Hz.xml
2018-05-02_1655_H1SUSSR2_M1_WhiteNoise_T_0p01to50Hz.xml
2018-05-02_1655_H1SUSSR2_M1_WhiteNoise_V_0p01to50Hz.xml
2018-05-02_1655_H1SUSSR2_M1_WhiteNoise_Y_0p01to50Hz.xml

/ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SR2/Common/Data/
2018-05-02_H1SUSSR2_All_OSEM_ASDs.xml


The .pdf attachments are the standard transfer function results. 

The image (.png) attachments show SR2's OSEM ASDs compared against the respective stage's expected sensor noise. Also shown is MC3's for comparison. 
In these, we see that -- although there is a hump in all OSEMs above 1 kHz that deviates from our expected sensor noise, MC3's results confirm my suspicion that this is a common feature to all OSEMs read out by UK satellite amplifiers. 

PSL mode matching work continues, thus the PSL weekly report reflects the non-standard configuration.  For details on PSL status contact Peter King or Rick Savage.

---

Laser Status:
SysStat is good
Front End Power is -0.0005444W (should be around 30 W)
HPO Output Power is -0.02777W
Front End Watch is RED
HPO Watch is RED

PMC:
It has been locked 0 days, 0 hr 0 minutes (should be days/weeks)
Reflected power = 0.0538Watts
Transmitted power = -0.06045Watts
PowerSum = -0.004387Watts.

FSS:
It has been locked for 0 days 0 hr and 0 min (should be days/weeks)
TPD[V] = 0.0707V (min 0.9V)

ISS:
The diffracted power is around 1.9% (should be 3-5%)
Last saturation event was 0 days 4 hours and 55 minutes ago (should be days/weeks)

Possible Issues:
Front End Power is Low
FSS TPD is low
ISS diffracted power is Low
LRA out of range, see SYSSTAT.adl

FAMIS 6948

BS_ST1_CPSINF_H1_I, BS_ST2_CPSINF_H1_I and BS_ST2_CPSINF_V1_I appear high.
ITMX_ST1_CPSINF_H2, ITMX_ST1_CPSINF_V2, ITMX_ST2_CPSINF_H2 and ITMX_ST2_CPSINF_V2 appear very low.

Scripts reported:

BS_ST1_CPSINF_H1_I high freq noise is high!
ETMX_ST2_CPSINF_H1 high freq noise is high!
ETMX_ST2_CPSINF_H2 high freq noise is high!
ETMX_ST2_CPSINF_H3 high freq noise is high!
ETMX_ST2_CPSINF_V1 high freq noise is high!
ETMX_ST2_CPSINF_V2 high freq noise is high!
ETMX_ST2_CPSINF_V3 high freq noise is high!

The measured dew point today was -8C.  We have not been measuring this frequently enough and can't definitively determine if this is a new problem, or, if it has been ongoing for some time (weeks?).  Rather, we have just checked to see if the drying towers have been experiencing "Switching Failures" which are the most typical problem associated with poor dew point numbers. 

The pressure of the air which backflows through the towers during their "regeneration" cycle (coincidentally referred to as "purge-air") was about 40 psi -> 65 psi is nominal for the 4 minute cycle time being used.  I was only able to increase/adjust this to ~50 psi .  So, something is amis.  This issue is likely the majority of the problem but, additionally, there is a second problem.  That is that the gauge at the output of the vent/purge air supply skid is showing 0.1 psi -> as if the demand from the VEA was greater than could be supplied by the skid.  This is surprising as the observed demand at the vent/purge check valve is modest when the 2 1/2" vent/purge valve is closed.  One explanation could be that there is a leak in the parallel connected TMDS piping.

We will address this as soon as we can.  

On the NE pillar of the SRM, spotted the witness optic looking pinker than it should and maybe even seeing the pull tab.  Decided to ignore my growling stomach and call my bet. Sure enough, while the front surface FC was removed, the back side was still in place.  See the attached photo after I flipped the Optic in the holder on the bench.  I looked through the ham5 alogs and see no indication of anyone setting up the CC witness optic although I may have missed it or that was not logged.  And, someone may have the scheme of pulling the backside FC and plan to remove and flipped the optic at the last minute but I'm not so sure.  If correct, this means we had this batch of FC under vacuum for about 20 days.  I was going to replace everything with new but realized that was unnecessary.  The optic is ready to have its FC pulled to exposed the clean surface.

This morning Ken D. de-energized the additional 10 kW heater in the CP4 bake enclosure by simply switching the breaker off inside the panel. This supplemental heater did not seem to hinder the termperature profile - the original 20 kW heater ramped up from 20% output to 40% output (note:  before we added insulation, we could not ramp past 100C without this added heat due to leaks). Also this morning MCE fixed the ramp software by removing the limit programmed in during testing on Monday. Lost some heat in the process; soak set point is 110C (to match TC#4) - will ramp to that, soak for 1 hr and then start ramp down.

Here it so round two of ramping down at 1C/hr.

Lock/Unlock tilt is just a couple urads.  Ended up taking off 600 grams of mass.  ISI left locked.

Bubba, Dave:

Due to on-going work on the reverse osmosis system in the wood-shed, I have bypassed the cell phone alarms for the RO system through to 11am PDT Thursday.

Her are the TFs repeated this morning--The horizontal local TFs look good just as they did last night; all three verticals are ratty while yesterday afternoon first V2 look ratty and the others were fine then after rebalance V3 looked okay and the the other to looked ratty and then they all looked bad.  Not sure if it was conditions or something in and out of being too close.

Attached are the TFs from this morning.  Will inspect the in chamber conditions shortly.   FWIIW, JimW thinks these are fine.

Betsy, Slawek, Sebastien

AMD1 and AMD2 have been installed in the ITMX and ITMY test masses. The install went well, and the epoxy curing passed the dynamic test. 24h of curing is required before moving to the next AMDs. Tomorrow, we will continue the work and install AMD3 and AMD4 in both chambers.

Fil, Georgia

Conclusion:

We believe that the ETMY LR ESD quadrant is disconnected somewhere in-chamber.

After problems with ESD-optical lever charge measurements, I tried to confirm that we are actually driving the LR quadrant by driving the individual ESD quadrants with a 4.3 Hz sine wave (30000 counts amplitude, with 100000 counts on the bias) and looking for the response on the optical lever pitch and yaw. A response was seen while driving the other 3 quadrants, but not the LR quadrant (see attached screenshot).

Fil and I went down to EY to check all the electrical connections outside the chamber. Between the HV chassis and the chamber feedthrough there is a resistor box and a pigtail connector. Everything outside the chamber is working as it should.

- We checked the connections in the resistor box, some connectors were loose but everything was connected. (Note the resistors in the box are actually bypassed, as their function (to limit current to the ESD electrodes) is now done inside the chassis. The box remains as an elaborate SHV-SHV connector.

- We drove the LL quadrant, with this signal hooked up to the LL, UL and LR quadrants at the resistor box, and only saw a response in LL and UL, confirming that we are driving up to the pigtail.

- We reseated the pigtail connector, repeated the above test, and saw nothing while driving the LR quadrant.

- Finally, we replaced the pigtail with a spare, and again saw nothing while driving the LR quadrant.

Now that both sites are running the 70 W, I've done a quick comparison of the periscope motion and the microphones.

The plot shows PSL periscope accelerometer (top) and mic (bottom) at LLO and LHO. LHO periscope has significantly more motion 20 - 300 Hz and around 1 kHz, though from Jenne's recent look at WFS, looks like the peaks at 350 Hz (PZT mount) and ~600 Hz are what get in as jitter. I recently did a make-up air test at LLO; there's no effect on the per acc at LLO but maybe LHO should do a quick on/off check to see if it couples in at LHO.

The orange lines in the plots show from a day before red, before Peter and Jeff did some noise reduction work, so you can see the improvement orange to red, especially at high freq.

As for microphones, it looks like LHO's is sensor limited and heavily polluted by 60 Hz. PEM runs differential, so maybe something along the way is getting onto the shield? We see this in many of the mics there. Note that LLO has different microphones that have lower sensor noise, but not enough to account for the difference we see now between the sites (the microphone-type difference is included in the calibration).

I took LHO data during the middle of the night 4/24 and 4/25; I'm told the PSL was in science mode and both sites have HAM6 clean rooms running.