Hugh, Jim, Krishna

This is regarding the idea of placing a seismometer on the BRS-Y platform in order to improve coherence and hence tilt-subtraction. The brief summary is that we found excess low-frequency noise in the seismometer when it was placed on the table on BRS-Y. Hugh had attempted to reduce the noise by adding thermal insulation to the table and the instrument. The last alog on this is 35426.

In the recent data I looked at, this excess noise looks non stationary - it seems to get worse with elevated wind. This suggests it is likely not thermal. The seismometer data shows that the table has much higher motion in the 10-100 Hz as compared to the ground. Since the seismometer isn't held securely on the table, it is possible this excess high-frequency motion is causing it to move ever so slightly, which could look like excess low-frequency noise (step changes). We are attempting to mount the seismometer securely to the table using M10X1.0mm threaded rods and holes to be machined into the table. Results and plots will be posted in a few days.

J. Kissel

Taking the data from this morning's aLOG as my target frequencies, I've tuned BRD S/Ns 015 and 016 to match the highest vertical (a.k.a bounce) and roll mode frequencies of the newly suspended H1 SUS ITMX. Results are attached and tabulated below:

    'Target [Hz]'    'BRD S/N'    'Mean Fit Freq. [Hz]'    '% Diff [%]'
    '9.806'          '015'        '9.853'                  '0.49'      
    ''               '016'        '9.812'                  '0.066'     
    ''               ''           ''                       ''          
    '13.927'         '015'        '14.033'                 '0.76'      
    ''               '016'        '13.926'                 '0.009'

Setup for measurement is as described in the HAM ISI TMDs (see 38741) using corroborating evidence from both the laser vibrometer and a primitive shadow sensor setup. To calculate the above "Mean Fit Frequency," I used a least square's minimization with a Lorentzian seed function,
    fit(f) = (1/Q)^2 ./((f - f0).^2 + (1/Q)^2) + C 
to fit both sensors' data to obtain the measured frequency with the noise, and then took the mean of the two sensors' results.
    
Betsy and Travis are installing these BRDs as I type.

Krishna, Jim, Hugh,

Today, we began the task of replacing the gravitational actuator/damper with capacitive actuators for the BRS-X. This will make it nearly identical to BRS-Y in control and behaviour‌ and eliminate the few incidences of damper problems we have had with BRS-X.

We opened up the vacuum can and machined a hole in the aluminum thermal shield for the capacitor plate wire. The capacitor plate was then glued to the thermal shield using TorrSeal epoxy, which takes a day to set fully. Tomorrow we will complete the wiring. We will also attempt to reduce the offset between the center of mass and the pivot axis to make it less sensitive to horizontal acceleration.

Sometime over the last few days, we lost functionality of the F1 (Face 1) BOSEM on the main chain of ITMX, causing a bit of hunting and measuring.  The chain would not damp and although there were peaks in proper places on all TFs, the noise floor for the PITCH measurement was well below where it should be.  This pointed to F1 as having issues and hence the swap.

S/N 091 came out, 049 went in.

Note, we are seeing that many OSEM OLVs have been decaying over time.  So, while we aren't surprised that 091 was much lower than it should be, likely we need to take a closer look at all BOSEM trends.

WP7196, DCC-T1700481, ECR-E1700367, FRS-9309

Brian, Jim, Dave:

h1isi[etmx, etmy, itmx, itmy, bs] models were compiled and restarted. Their DAQ channel lists increased by six slow channels each (example list for ITMY shown below).

The isi2stagemaster.mdl was modified. It now uses C code in the file ISIWD_LONGDAMP.c in place of ISIWD_GPS.c

+: slow channel H1:ISI-ITMY_ST2_WD_MON_RESET_PENDING added to the DAQ
+: slow channel H1:ISI-ITMY_ST2_WD_MON_HOLD_REMAINING added to the DAQ
+: slow channel H1:ISI-ITMY_ST1_WD_ST1_FLAG_GEN_DELAY_TIME added to the DAQ
+: slow channel H1:ISI-ITMY_ST1_WD_ST1_FLAG_GEN_DELAY_TIME_MON added to the DAQ
+: slow channel H1:ISI-ITMY_ST1_WD_MON_RESET_PENDING added to the DAQ
+: slow channel H1:ISI-ITMY_ST1_WD_MON_HOLD_REMAINING added to the DAQ
 

We have added a couple of convenience functions to LDVW that might be of interest.

BRUCO (brute force coherence) written and maintained by Gabriele Vajente,

WDQ (omega scans on a standard list of channels) uses either the Matlab W pipeline maintained by Brennan Hughey or dmt_wscan written and maintained by John Zweizig.

LDVW provides a simple web interface that launches a condor job to run these processes. Results are available on the leas-jobs machine at CIT.

BRUCO interface is available at https://ldvw.ligo.caltech.edu/ldvw/Bruco
WDQ is at https://ldvw.ligo.caltech.edu/ldvw/Wdq

If any part of the interface is counterintuitive or you have any trouble running please contact me at joseph.areeda@ligo.org

J. Kissel

I'm headed into the optics lab to tune the Bounce / Roll Dampers (BRDs) for ITMX, so I want to reconfirm the measurements of the highest vertical (a.k.a. "bounce") and roll modes of the newly suspended ITMX. The previous measurement of the highest vertical & roll modes (LHO aLOG 39106) was taken while the SUS was still rubbing all over and poorly aligned. Travis and Betsy worked hard yesterday to find that the majority of Top to Top mass transfer functions were clean (barring a believed malfunctioning F1 sensor); aLOG pending. 

The results are reported below (and ASDs of the PUM/L2 and UIM/L1 stage are attached). 

Meas Date     2017-10-20      2017-10-31
V4 [Hz]         9.8022          9.8056
R4 [Hz]         13.927          13.927

The frequency bin width of both measurements is 0.5 mHz, and the effective bandwidth is 0.732 mHz.

The bounce frequency has increased ever-so-slightly (9.8056 - 9.8022)/9.8022 = 0.00035 (i.e. 0.03% increase), but the roll mode remains the same. Given our ability to tune the BRDs is at the 1% level, I expect / will be happy to get something between the 9.8056 .* (1 + [0.01 -0.01]) = [9.9037 9.7075] range.

This morning I completed the weekly PSL FAMIS tasks.

HPO Pump Diode Operating Current Adjust (FAMIS 8446)

With the ISS OFF, I adjusted the operating current of the HPO DBs, changes summarized in the below table.  A screenshot of the PSL Beckhoff main screen is attached for future reference, as usual.

DB operating temperatures remain unchanged.  The HPO is now outputting 155.1 W, and the ISS is back ON.  This completes FAMIS 8446.

PSL Power Watchdog Reset (FAMIS 3674)

I reset both PSL power watchdogs at 16:49 UTC (9:49 PDT).  This completes FAMIS 3674.

Yesterday, Travis found the mechanical rubbing point on the ITMY - we ran a few short TFs and things look much more suspended.  The beam still is on the oplev, I made some small bias adjustments to center it up, but we should be ready for a full suite of TFs as only cleaning is left to do on this unit, which won't happen until closer to closeout.

TITLE: 10/31 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    Wind: 9mph Gusts, 7mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.15 μm/s
QUICK SUMMARY:

Richard came into my office this morning to tell me that the laser was off.  Pulled up the laser status
screen to find that power watchdog was activated ~12 hours 20 minutes ago (~6 pm Monday).  The laser
was brought back.

J. Kissel

I've B&K hammered the response of a bunch of other stand-alone components in HAM2: New MC13 Table Baffle, PSL DownPeriscope, MCREFL Periscopes, and New ISI Table Baffles. The prognosis is not good. Every component aside from the PSL down-periscope has resonant features below, if-not-well-below 150 Hz -- the original requirement from the SEI team to keep ISI 30 Hz UGF control loop design possible. Granted, the MC REFL Periscopes haven't really changed, but this data shows that (a) they are different from each other, and (b) that Periscope 2 is confirmed rattly mess. I can only hope that we can some how stiffen & and damp, instead of just shoving viton everywhere. I fear it's far too late in the schedule...

This being said, I must give props to the SLiC design team for ramming through an incredibly quick design-to-installed turn-around, and I appreciate that not everything could have been thought. We know from LLO that all this new baffling is doing the right thing as far as scattering goes.

See the .pdf for transfer functions.

I'll note that *everything* I hammered in HAM2 (including PRM and PR3 from LHO aLOG 39212) shows these resonant features at ~10.6 and 12.4 Hz. However, the ISI table baffles (a.k.a. beard baffles) seem to show this feature more prominently, and their mounting looks ... less-than-stiff ... so my guess is that since the accelerometer is mounted to the table in these measurements, they're coupling to every measurement. BUT, this is just a guess. I have a tough time believing that there's enough moving mass in those baffles to resonate as low as 10-12 Hz.

Aside from this common feature, I list the remaining prominent low-frequency features here in tabular form for future reference:
    DOF                       IFO Y                                    IFO X
    MC1/3 Table Baffles       [21.5 29.38 44.62]                       [29.62 36.88]
    PSL Down Periscope        [238.4]                                  [269.8]
    ISI HAM2 Table Baffle     [12.38 40 60.75]
    MCREFL Periscope 1        [124.6 124.8 140.8       194.6]          [22.00       42.25 141.2 167.9 195.1 ]
    MCREFL Periscope 2        [31.75 124.6 142.6 167.8 201.4 285.0]    [22.38 31.25 48.12 143.5 167.6 201.6 223.6]

Pictures are attached to guide discussion and aide any repeat measurements in the future.

• PSL beam aligned to the IMC using the new MC1 iris
• MC1 and MC2 alignment slider values are within 40urad of previous values
• MC3 alignment sliders have changed significantly
  • BEFORE: Pitch slider: -3911, Pitch OSEM: -3606, Yaw slider: -490, Yaw OSEM: 500
  • AFTER:    Pitch slider: -461, Pitch OSEM: -874, Yaw slider: --2260, Yaw OSEM: -1356
• alignment snapshots attached

- Ed, Keita, Cheryl

S Cooper, J Warner

I've been using a particle swarming script developed by Conor, to design some sensor correction filters in different environmental conditions., the method used by the script is described in G1700841. 

I chose a starting point of GPS time 1193385618 (8AM 30th October 2017 UTC) and used data for 2 hours on ETMY. During this time the microsisem was around 0.2-0.3 um/s and the wind speed was around 10m/s. I configured the swarm to have 4000 particles, set the RMS counting from 2Hz down to 1mHz, set minimum and maximum Q's to be 0.05 and 5 respectively and set the gains to range from 0.95 and 1.05. The result of this swarming produced the filter shown in blue in the first plot and its complement in red, plotted against the sensor correction filters currently used (Filter Module 5 CML BB). 

For these conditions, on this chamber the ending velocity RMS (how we're measuring how well the filter performs) is basically equal to the sensor correction filter currently used. Nevertheless Jim and I will try this filter out on ETMY and see whether this has any problems / benefitsover the old filter overnight on ETMY.

It appears that some process variables are taking on values with characters that do not conform to JSON:

Oct 18 11:10:12 conlog-master conlogd[7334]: terminate called after throwing an instance of 'sql::SQLException'
Oct 18 11:10:12 conlog-master conlogd[7334]: what():  Invalid JSON text: "Invalid escape character in string." at position 44 in value for column 'events.data'.
Oct 18 11:41:52 conlog-master conlogd: Server started. prefix: 'H1:CDS-CONLOG_' database: 'conlog' max inserts: 500 max time: 30 keep alive period: 30 time source: 0 create_messages: 1
Oct 18 11:59:32 conlog-master conlogd[8524]: terminate called after throwing an instance of 'sql::SQLException'
Oct 18 11:59:32 conlog-master conlogd[8524]: what():  Invalid JSON text: "Invalid escape character in string." at position 44 in value for column 'events.data'.
Oct 18 12:19:34 conlog-master conlogd: Server started. prefix: 'H1:CDS-CONLOG_' database: 'conlog' max inserts: 500 max time: 30 keep alive period: 30 time source: 0 create_messages: 1
Oct 18 12:34:12 conlog-master conlogd[9092]: terminate called after throwing an instance of 'sql::SQLException'
Oct 18 12:34:12 conlog-master conlogd[9092]: what():  Invalid JSON text: "Invalid escape character in string." at position 44 in value for column 'events.data'.

The same error repeats at each loading of the channel list.

The parts in question are D1101911 & D1101910.

HAM2: I've installed a QPD cable strain relief on IM4 trans. See first attachment.

HAM3: Done with MC2 trans and POPB, but not POPA.

For POPA, 1/4-20 screw wouldn't go in easily (I only tried for a minute or two) and I didn't bother to keep trying because I remember that this was a problem in the past for some of the QPDs (alog 19168 for TMSX).

One set of parts is left on the wire shelf on the work table in HAM2 cleanroom (top right of the wire shelf). If the 1/4-20 wouldn't cooperate, I would recommend to do the same solution as the above alog entry.