Displaying reports 45861-45880 of 86532.Go to page Start 2290 2291 2292 2293 2294 2295 2296 2297 2298 End
Reports until 14:45, Monday 07 May 2018
H1 SQZ (SQZ)
nutsinee.kijbunchoo@LIGO.ORG - posted 14:45, Monday 07 May 2018 (41868)
HAM6 photos before close out

Here I attached some of the overhead shots of HAM6 table just before we closed out last time. Note that the quality of OPO overhead shot (with green light input) wasn't the best last time so I attached a better one from April 12th (no green light, first photo) when we were aligning the beam to the PSL. Overhead shot of OMC side of the table also came from April 12th (second photo). The rest of the photos were taken on April 26th.

 

While going through the photos I noticed a stray green beam hitting the back of a diode box (ASC DCPD?) and the OMC glass shroud.  These photos are 6th and 7th from the right. 

Images attached to this report
H1 AOS
jeffrey.bartlett@LIGO.ORG - posted 13:33, Monday 07 May 2018 (41867)
T240 & STS Centering (FAMIS #6415)
STS
2018-05-07 13:21:57.355505
There are 2 STS proof masses out of range ( > 2.0 [V] )!
STS A DOF Y/V = -4.561 [V]
STS A DOF Z/W = 5.58 [V]

All other proof masses are within range ( < 2.0 [V] ):
STS A DOF X/U = -1.631 [V]
STS B DOF X/U = 0.183 [V]
STS B DOF Y/V = 0.917 [V]
STS B DOF Z/W = -0.462 [V]
STS C DOF X/U = 0.299 [V]
STS C DOF Y/V = -0.139 [V]
STS C DOF Z/W = 1.083 [V]
STS EX DOF X/U = -0.108 [V]
STS EX DOF Y/V = 0.446 [V]
STS EX DOF Z/W = 0.219 [V]
STS EY DOF X/U = 0.226 [V]
STS EY DOF Y/V = -0.035 [V]
STS EY DOF Z/W = 0.531 [V]
Assessment complete.



T240
Averaging Mass Centering channels for 10 [sec] ...
2018-05-07 13:27:56.363239

There are 19 T240 proof masses out of range ( > 0.3 [V] )!
ETMX T240 1 DOF Z/W = -0.414 [V]
ETMX T240 2 DOF Y/V = -0.575 [V]
ETMX T240 2 DOF Z/W = -0.723 [V]
ETMX T240 3 DOF Z/W = 0.403 [V]
ITMX T240 1 DOF X/U = -1.033 [V]
ITMX T240 2 DOF X/U = -0.374 [V]
ITMX T240 3 DOF X/U = -1.208 [V]
ITMY T240 1 DOF X/U = -0.363 [V]
ITMY T240 1 DOF Y/V = -0.502 [V]
ITMY T240 1 DOF Z/W = -0.383 [V]
ITMY T240 2 DOF Z/W = -0.582 [V]
ITMY T240 3 DOF X/U = -1.121 [V]
ITMY T240 3 DOF Y/V = -0.307 [V]
ITMY T240 3 DOF Z/W = -1.553 [V]
BS T240 1 DOF X/U = -0.364 [V]
BS T240 1 DOF Y/V = -0.432 [V]
BS T240 2 DOF Z/W = -0.417 [V]
BS T240 3 DOF Y/V = -0.47 [V]
BS T240 3 DOF Z/W = -0.638 [V]


All other proof masses are within range ( < 0.3 [V] ):
ETMX T240 1 DOF X/U = -0.164 [V]
ETMX T240 1 DOF Y/V = 0.242 [V]
ETMX T240 2 DOF X/U = -0.216 [V]
ETMX T240 3 DOF X/U = -0.17 [V]
ETMX T240 3 DOF Y/V = 0.03 [V]
ETMY T240 1 DOF X/U = -0.063 [V]
ETMY T240 1 DOF Y/V = 0.175 [V]
ETMY T240 1 DOF Z/W = -0.123 [V]
ETMY T240 2 DOF X/U = 0.013 [V]
ETMY T240 2 DOF Y/V = -0.135 [V]
ETMY T240 2 DOF Z/W = -0.012 [V]
ETMY T240 3 DOF X/U = -0.141 [V]
ETMY T240 3 DOF Y/V = -0.066 [V]
ETMY T240 3 DOF Z/W = 0.142 [V]
ITMX T240 1 DOF Y/V = -0.261 [V]
ITMX T240 1 DOF Z/W = -0.227 [V]
ITMX T240 2 DOF Y/V = -0.262 [V]
ITMX T240 2 DOF Z/W = -0.16 [V]
ITMX T240 3 DOF Y/V = -0.098 [V]
ITMX T240 3 DOF Z/W = -0.209 [V]
ITMY T240 2 DOF X/U = -0.108 [V]
ITMY T240 2 DOF Y/V = -0.045 [V]
BS T240 1 DOF Z/W = -0.018 [V]
BS T240 2 DOF X/U = -0.232 [V]
BS T240 2 DOF Y/V = 0.088 [V]
BS T240 3 DOF X/U = -0.173 [V]
Assessment complete.

   Chamber closeout and Quad install work is underway at this time. 





H1 PSL
jeffrey.bartlett@LIGO.ORG - posted 13:12, Monday 07 May 2018 (41866)
Weekly PSL Status Report (FAMIS #7489)
Laser Status:
SysStat is good
Front End Power is -0.0078W (should be around 30 W)
HPO Output Power is 0.7958W
Front End Watch is GREEN
HPO Watch is RED

PMC:
It has been locked 1 days, 0 hr 52 minutes (should be days/weeks)
Reflected power = 16.42Watts
Transmitted power = 51.77Watts
PowerSum = 68.18Watts.

FSS:
It has been locked for 2 days 19 hr and 40 min (should be days/weeks)
TPD[V] = 1.838V (min 0.9V)

ISS:
The diffracted power is around 1.8% (should be 3-5%)
Last saturation event was 0 days 1 hours and 6 minutes ago (should be days/weeks)

Possible Issues:
Front End Power is Low
ISS diffracted power is Low
LRA out of range, see SYSSTAT.adl
H1 SEI
hugh.radkins@LIGO.ORG - posted 12:22, Monday 07 May 2018 (41865)
ITMX ISI Corner2 CPS Satellite rack swapped--fully operational now.

The attached photo shows to damage to the connector/back plane.  Fil is pretty confident that we can repair.  The problem is the lifting point on this door--rather than a strap with a large opening for shackles, it is a flange with a smallish hole.  This requires the door crew to have more elements in the lift rig--maybe we can improve that..it's only money.  Still, we should maybe look to moving these CPS racks to a different spot.

Further, many of the cables above the west side door on BSC3 (ITMX) are vulnerable to damage depending on how high this cable tray is being lifted--the cable tray is not too far from the feedthrus and cables are going thru the tray mesh or are on top of the tray so this also puts the feedthrus at risk.  I've filed FRS 10557 to mitigate this risk as much as possible.

Meanwhile--The ISI operates normally and sensor spectra look good.  St2 H3 CPS had some higher noise so that corner CPS was power cycled and the St2 H3 gauge board was un & re seated a few times; that action cleared the noise.

FRS 10551, WP 7531

Images attached to this report
H1 General
filiberto.clara@LIGO.ORG - posted 12:00, Monday 07 May 2018 - last comment - 10:25, Tuesday 08 May 2018(41863)
EY E-Stop button - cover added

To avoid the E-stop buttons from accidently being engaged a cover was added to the E-stop buttons at EY.

Comments related to this report
marc.pirello@LIGO.ORG - 10:25, Tuesday 08 May 2018 (41882)
Attached images of the E-Stop button covers at EY
Images attached to this comment
H1 General
filiberto.clara@LIGO.ORG - posted 11:53, Monday 07 May 2018 (41862)
Access Controls - EY

Reinstalled access control network switch at EY. Unit lost communication sometime las week. The SFP transceiver was replaced. Link lights show communication with network switch and newly installed cameras.

H1 SUS
filiberto.clara@LIGO.ORG - posted 11:49, Monday 07 May 2018 (41861)
EY ESD In-Vacuum Cabling

T1800199
alog 27589

Used a FieldFox Handheld RF Analyzer to look at the EY ESD in-vacuum cabling. Test description can be found in T1800199. Found similar cable lengths as described in the document for LLO EY in-vacuum cable lengths.

LR - 39.51 ft
UR - 39.97 ft
UL - 39.94 ft
LL - 40.24 ft
Bias - 42.63 ft

Lengths are at the feedthrough using a 3.5 ft jumper cable.

H1 AOS (DetChar)
ronaldas.macas@LIGO.ORG - posted 10:26, Monday 07 May 2018 (41859)
Live noise budget update

Ronaldas, Sheila

I have restructured previously used noise budget code (git repo, see /restructured_nb folder). This way it is easier to add other noises and debug the code. 

Afterwards we added additional noise sources:
1) actuator DAC noise - DAC noise from the test mass PUM based on the model in G1100968
2) DC readout quadratic term - see an alog DC readout quadratic term
3) osem sensors noise - noise from the top mass damping to the quad suspensions
4) thermal noise (updated to the most current GWINC version)

Attached plots show a contribution from recently added noises (recent_contribution_NB.jpg) and an example of total noise budget (noise_budget.jpg). Plots are made using July 4th 2017 data, a lock before the earthquake that increased LHO noise.

Currently we are working on two noises:
1) residual gas in vacuum: squeezed film damping noise and residual gas in arms.
2) coherent noise: a coherence based projection of jitter from the bullseye sensor upstream of the PMC, which was contributing to the DARM noise from 30Hz-1 kHz in this lock stretch

Thanks Jeff for suspension quadmodel and controls design summary table - that saved tons of time!

Also, a note: let me or Sheila know if you think there is a noise source that should be in this noise budget.

Images attached to this report
H1 PSL
jeffrey.bartlett@LIGO.ORG - posted 10:12, Monday 07 May 2018 (41858)
Monthly PSL Filter Inspection (FAMIS #8308)
   Added 50ml water to Crystal chiller. Added 100ml water to Diode chiller. Both Crystal and Diode filters are clean and clear. No debris noted in either filter. 
H1 AOS
jeffrey.bartlett@LIGO.ORG - posted 09:55, Monday 07 May 2018 (41857)
09:00 Meeting Minutes
UNTIL FURTHER NOTICE, DO NOT DRINK TAP WATER.
There are some elevated contaminate levels in the water, which are being addressed.
 
Please remember to close your completed work permits.
 
 
VAC:
Torqueing bolts on BSC 1 & BSC3
Starting the CS pump down
 
PSL:
Cheryl will be working on IO alignment and PD installation in the PSL enclosure

 

CDS:

Work on access control system continues. These is cabling pulling in the LVEA and installation work in the staging building.
 
SUS:
ETM-X installation and alignment work
 
SEI:
Hugh is swapping the CPS rack for ITM-X
 
MISC:
Dick G. continuing work on RF measurements
 
Tuesday Maintenance:
Several model restarts
Guardian updates
PSL ISS model work
H1 PSL (PSL)
richard.savage@LIGO.ORG - posted 08:02, Monday 07 May 2018 (41856)
PSL status as of last Friday evening

JasonO, PeterK, RickS

Last Friday evening, we left the PSL in a state that will hopefully be sufficient for commissioning-related activities this week, during which all three of us will be on travel.

The full output power, 65-70 W,  is directed into the PMC, with about 52 W transmitted. 

The PMC output is directed to the beam dump directly downstream of the PMC.  Thus, the half-wave plate at the PMC output will have to be rotated manually to send the PSL output beam through the EOM and into the MC.

Note that the EOM mount is quite unstable.  The springs in the 5-axis NewFocus stage can accommodate the EOM weight if all forces are downward.  But with the new RF cables (and maybe even with the old RF cables) the stability of this mount is marginal.  Attention to EOM beam centering and mount stability (cable strain relief, etc.) should be given when directing the PMC output through the EOM.

The PMC and FSS loops are performing nominally, but the ISS loop is disabled (AOM not yet installed).

After the past two weeks of working with the 70-W amplifier, we think we finally have a good understanding of the modematching to the PMC.   The PMC visibility is currently about 82%.  This is limited by a "pedestal" that is apparently due to either a Front End output beam with this pedestal or to having too small a beam entering the 70 W amplifier.  When an iris is installed upstream of the PMC and closed to the point that 10-15 W is occluded by the aperture, the PMC visibility increases to about 92-94%.  This is corroborated by the  Beam Scan data (see attached BeamScan data and images).

When time allows, we will scrutinize the Front End output beam (apparently this was not optimized after swapping out the NPRO some time ago).  Then, after consulting with Mike Frede et al. at NeoLase, we will re-visit the modematching into the 70 W amplifier, then the modematching into the PMC.

 

Images attached to this report
LHO VE
kyle.ryan@LIGO.ORG - posted 10:46, Sunday 06 May 2018 (41855)
1040 hrs. local -> Kyle on site briefly making CP4 RGA variac adjustments

1050 hrs. local -> Leaving site now.  

LHO VE
kyle.ryan@LIGO.ORG - posted 06:17, Saturday 05 May 2018 (41854)
Kyle on site

0555 - 0620 hrs. local -> Briefly in to make manual adjustments @ CP4 RGA and to shut down the Corner Station's purge-air supply.  

 

0620 hrs. local -> Leaving site now.

H1 ISC (IOO)
daniel.sigg@LIGO.ORG - posted 18:00, Friday 04 May 2018 (41852)
EOM Drivers moved outside PSL enclosure

Fil Peter Rick Jason Daniel

We moved the EOM drivers from under the PSL table to the bottom of the PSL-R2 rack. The setup itself is still the same until we get the RF combiner/amplifier. Before connecting back to the EOM, we remeasured the RF power using the same settings of 23.4 dBm and 27.0 dBm for 9 and 45 MHz, respectively. As a comparison, we also give the numbers from Koji's alog 41435.

Frequency old alog 41435 @rack PSL-R2 @ EOM Cable loss Difference
9.1 MHz 23.56 dBm 23.49 dBm 23.33 dBm 0.16 dB –0.07 dB
24.07 MHz 24.60 dBm 25.33 dBm 24.90 dBm 0.43 dB +0.30 dB
45.5 MHz 23.76 dBm 23.84 dBm 23.48 dBm 0.36 dB –0.28 dB
118 MHz 9.84 dBm 10.22 dBm 9.66 dBm 0.56 dB –0.18 dB

The cable loss for the 24 MHz signal seems a little high and might be due to an imperfect VSWR. Otherwise, the RF levels are close, but the RF phases will have changed.

More details in T1800196.

LHO VE
kyle.ryan@LIGO.ORG - posted 17:03, Friday 04 May 2018 (41851)
Valved-out purge air

As doors are on and the VE is "buttoned up" in the Corner Station, the purge-air isn't needed and isolating it elimiantes any possibiltiy of over-pressure should the regulation fail.

H1 SUS
jeffrey.kissel@LIGO.ORG - posted 16:33, Friday 04 May 2018 (41847)
H1 SUS ITM Checkout Prior to Doors; OK for Doors
J. Kissel

Standard health checks on BSC1 / BSC3 suspensions today (H1SUSITMX / H1SUSITMY) as we prepare to close out. All suspensions pass their tests. We're OK for doors.


/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMX/Common/Data/
    2018-05-04_H1SUSITMX_AllStages_OSEM_ASDs.xml

/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMX/SAGM0/Data/
    2018-05-04_2129_H1SUSITMX_M0_WhiteNoise_L_0p01to50Hz.xml
    2018-05-04_2129_H1SUSITMX_M0_WhiteNoise_P_0p01to50Hz.xml
    2018-05-04_2129_H1SUSITMX_M0_WhiteNoise_R_0p01to50Hz.xml
    2018-05-04_2129_H1SUSITMX_M0_WhiteNoise_T_0p01to50Hz.xml
    2018-05-04_2129_H1SUSITMX_M0_WhiteNoise_V_0p01to50Hz.xml
    2018-05-04_2129_H1SUSITMX_M0_WhiteNoise_Y_0p01to50Hz.xml

/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMX/SAGR0/Data/
    2018-05-04_2156_H1SUSITMX_R0_WhiteNoise_L_0p02to50Hz.xml
    2018-05-04_2156_H1SUSITMX_R0_WhiteNoise_P_0p02to50Hz.xml
    2018-05-04_2156_H1SUSITMX_R0_WhiteNoise_R_0p02to50Hz.xml
    2018-05-04_2156_H1SUSITMX_R0_WhiteNoise_T_0p02to50Hz.xml
    2018-05-04_2156_H1SUSITMX_R0_WhiteNoise_V_0p02to50Hz.xml
    2018-05-04_2156_H1SUSITMX_R0_WhiteNoise_Y_0p02to50Hz.xml

/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMY/SAGM0/Data/
    2018-05-04_H1SUSITMY_AllStages_OSEM_ASDs.xml

/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMY/SAGM0/Data/
    2018-05-04_2105_H1SUSITMY_M0_Mono_WhiteNoise_L_0p02to50Hz.xml
    2018-05-04_2105_H1SUSITMY_M0_Mono_WhiteNoise_P_0p02to50Hz.xml
    2018-05-04_2105_H1SUSITMY_M0_Mono_WhiteNoise_R_0p02to50Hz.xml
    2018-05-04_2105_H1SUSITMY_M0_Mono_WhiteNoise_T_0p02to50Hz.xml
    2018-05-04_2105_H1SUSITMY_M0_Mono_WhiteNoise_V_0p02to50Hz.xml
    2018-05-04_2105_H1SUSITMY_M0_Mono_WhiteNoise_Y_0p02to50Hz.xml

/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMY/SAGR0/Data/
    2018-05-04_2130_H1SUSITMY_R0_L_WhiteNoise_0p02to50Hz.xml
    2018-05-04_2130_H1SUSITMY_R0_P_WhiteNoise_0p02to50Hz.xml
    2018-05-04_2130_H1SUSITMY_R0_R_WhiteNoise_0p02to50Hz.xml
    2018-05-04_2130_H1SUSITMY_R0_T_WhiteNoise_0p02to50Hz.xml
    2018-05-04_2130_H1SUSITMY_R0_V_WhiteNoise_0p02to50Hz.xml
    2018-05-04_2130_H1SUSITMY_R0_Y_WhiteNoise_0p02to50Hz.xml


I attach screenshots of the ASDs of all OSEMs, that -- although hairy, don't show egregious signs of ground loops (regular combs and a highly elevated, high-frequency noise floor).
I also attach a smattering of screenshots of the transfer functions, just to visual prove that all looks good.
I'll wait until we pump back down before taking the nominal 0.01 Hz resolution TFs.

Notes: 
- ITMX R0 has had large vertical and pitch offsets in place when I took over from Betsy. We believe these are incorrect settings relics, as we've proven several times that they're no longer needed after the corner station temperature increased after a long cold 2016-2017 winter (see LHO aLOGs 36230, LHO aLOG 36335). Besides, we've also completely de-installed and re-installed that chain in October 2017 (see, among others, LHO aLOG 38873). 
- Similarly, Betsy actively attacked rubbing items on ITMY during this vent (mentioned briefly in LHO aLOG 41849). Thus, I removed the ~50k vertical offset that had been in place on the main chain -- which we'd recently identified was still needed (LHO aLOG 40789), and the chain appears clear of rubbing. We'll see what happens once we pump down!
Images attached to this report
H1 SEI
jim.warner@LIGO.ORG - posted 16:18, Friday 04 May 2018 (41848)
ITMY ISI tfs look good, ITMX has low response in one corner

After Betsy finished with FC removal, I unlocked both ITMY & ITMX ISIs. Running tfs now, ITMY is done and looks good (first two plots).

ITMX looks like it has one corner that has consistently ~10% low response (last two plots), but this is the chamber and corner that Hugh found the cables damaged on so I suspect that maybe the actuator cables got pulled when the CPS rack got attacked. Probably very difficult to assess right now with the cleanroom in the way. Doesn't look like a table short or bad sensors, so I think we are still okay.

Images attached to this report
H1 SUS (SEI, SUS)
betsy.weaver@LIGO.ORG - posted 16:18, Friday 04 May 2018 (41849)
Closeout of BSC1 and BSC3

Today, with the help of Slawek and Seb in and out of chamber, Kissel on TFs, and Jim and Fil on ESD checks and ISIs, we:

Note - Earlier in the week Kyle mentioned concern for the cleanroom joint around the top of these BSC doors - when I inspected yesterday (and today) they are fine.  Earlier in the week, Mark and Tyler built the Ameristat dam around the back of the door flanges like always.  So no problems...

 

LHO General
patrick.thomas@LIGO.ORG - posted 16:04, Friday 04 May 2018 (41846)
Ops Shift Summary
15:04 UTC Peter done working by PSL racks
15:27 UTC Visitor through gate to meet Bubba
15:35 UTC Mark to LVEA to put away equipment near HAM3 from ion pump work
15:35 UTC APS through gate
16:00 - 16:09 UTC System lead meeting in CR
16:12 - 16:16 UTC Corey to LVEA to assess area around HAM6
16:24 UTC Peter to PSL enclosure
16:41 UTC Jeff B. to LVEA to remove dust monitors 4 and 5
17:01 UTC Jeff B. done
17:01 UTC Betsy to biergarten
17:11 UTC Travis to end X to get locking bracket and check health of suspension
17:28 UTC Filiberto and Daniel to PSL racks
17:33 UTC Travis back from end X, heading to LVEA to give part to Betsy
17:38 UTC Travis back
18:04 - 18:14  UTC Tour in CR
18:21 UTC Kingsoft water through gate, here to take samples
18:54 UTC Tour in control room
19:05 UTC APS through gate
19:15 UTC Peter back
19:37 UTC Betsy back
20:03 UTC Betsy and Filiberto to biergarten
20:07 UTC Bubba to mid and end stations to lubricate fans
20:18 - 20:24 UTC Keita turning on power to ISS second loop chassis
20:50 UTC Hugh to end X to check HEPI
20:57 UTC Greg to LVEA to replace TCS laser enclosure panels
21:01 UTC ITMY ISI being unlocked
21:05 UTC Filiberto to LVEA to talk to Greg
21:09 UTC Jeff K. running transfer function measurements on ITMY
21:10 UTC Hugh back
21:11 UTC Jason and Rick to PSL enclosure
21:24 UTC Filiberto to PSL racks, install EOM driver panel
21:25 UTC Tyler, Mark to LVEA to put door on ITMY BSC chamber
21:38 UTC Peter to PSL racks
21:55 UTC Travis to LVEA to help with closeout
21:59 UTC Betsy, Travis back
21:59 UTC Keita to PSL racks to check PSL ISS second loop board
22:42 - 22:56 UTC Tour in CR
22:48 UTC Tyler and Mark done, BSC1 and BSC3 doors are on
23:00 UTC Peter done
23:01 UTC Filiberto done
H1 SUS (CDS, ISC, SQZ, SUS)
keita.kawabe@LIGO.ORG - posted 14:51, Friday 27 April 2018 - last comment - 10:24, Monday 07 May 2018(41722)
HAM6 ground loop today (TVo, Corey, Jim, JeffK, Fil, Keita)

ZM1 in-chamber cable between the feed through and the cable bracket on HAM6 was swapped, loop gone.

It was swapped and the ground loop of that part was fixed. But the new cable didn't have screws in DB25 to secure the connection, so we're transplanting the screws from the old cable to the new one.

ZM1 DB25-micro DB9 cable (that goes to the BOSEMs), disconnecting/reseating/shimming/tilting done, loop gone.

There was also some problem(s?) with ZM1 DB25 to micro DB9 cable. It's the same failure as the one reported for OM3 yesterday (https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=41709). Jim tried to angle the connectors to clear the problem, which helped three of them but LR was persistent. He half-disconnected the micro DB such that no metal part of the back shell could possibly touch the aluminum BOSEM body/plate but there's still electrical connections to the pins, and the problem still persisted, which sounded like a problem of BOSEM itself. However, when we totally pulled the BOSEM from the TT cage and connected it back to the cable, we didn't see ground loop.

I inspected it and saw a tell-tale tiny gap between the back shell and the BOSEM/plate. As a preventative measure we performed foil-shimming-shell-tilting procedure explained in https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=12346. First attachment shows "after" photo (there's no "before"), there are three potential short circuit points, two (circled in yellow) look much better, one (red) is actually better than before but I can only barely slip a sheet of foil through. The second attachment shows the foil used as a shim underneath the micro DB9 on the BOSEM body. It's really important that the cable side connector doesn't sit on this foil. The third one is an in-situ picture. Looks scary close but actually there's a gap. Suboptimal but this is as much as we can do.

OMC QPDs is left as is, nothing to fix.

After going back and forth between Koji and Rich, I'm convinced that this is a known symptom.

Images attached to this report
Comments related to this report
filiberto.clara@LIGO.ORG - 16:17, Friday 27 April 2018 (41727)

Ground loop checks were completed after in chamber cabling work.

SUS checked out good with the exception of OM3 (ISC_238).
ASC WFS cabling (ISC_255 & ISC_266) at rack side (DB15 connector) does not have pin 8 connected to shield. Shield tied to both pins 14 and 15.
Beam diverter cables (ISC_316 & ISC_317) at rack side (DB9) don't have pin 5 installed. Shield is tied to earth ground.
PZT cabling at rack side (ISC_409) does not have shield and pin 13 tied together.
See entry above from Keita regarding OMC QPDs.

keita.kawabe@LIGO.ORG - 19:34, Friday 27 April 2018 (41731)

OM3 problem comes back, fixed by cable routing and PEEK tubings, (Fil, Ed, Corey, TVo, Keita)

Fil reported that OM3 problem was back. It was really inconsistent, the only thing that was consistent was that when we remove DB25 cable at the OM3 bracket and lift it up from the table the short circuit is gone.

The biggest problem was that the DB25 cable was going from the OM3 bracket to the fast shutter and was pressed against the fast shutter body. The corner of the fast shutter body ate into the mesh of the DB25 cable and contacted the shielding. Each time we touch that part of the cable the resistivity of the short circuit changed from zero to open and anywhere in-between. That this was new to us makes sense because we've moved OM3 and FS after O2.

I installed a new cable clamp to pull the cable away from the fast shutter to reduce the pressure (the FS-OM3 distance is so short I was worried about making a kink at the connector if I try to completely pull the cable away from FS) and put a short PEEK tubing that is a leftover from TMS cable insulation (first attachment).

We also observed that wiggling the micro DB cable sometimes changed open/short, and it wasn't clear if this was due to me accidentally touching/affecting DB25 cable or if there's another short circuit path via cable shield. I installed another PEEK tubing to UR coil micro DB cable where it was bending at the edge of the OM3 cage (second attachment, red arrow points the tubing).

After these OM3 was consistently clear of the ground loop.

As a side note, we removed LR coil because I thought (in error) at some point that LR BOSEM was suspect. We put it back in, and measured open counts (20460 or so) and set the depth such that the input becomes half of the open number. We also adjusted LL depth but didn't touch UR and UL as they looked good.

ISI was unlocked

After removing all tools from the ISI table, ISI was unlocked by Corey.

No need for ground loop test again

We didn't touch any of the cables except OM3, so no need to test ground loop again.

Images attached to this comment
corey.gray@LIGO.ORG - 10:24, Monday 07 May 2018 (41860)

In ICS, I've removed the cable (D1000225/S1106893 & gave it a Defect record), which was suspected for causing part of the ground loop for ZM1, from the HAM6 Top Level Assy load & added the new cable (D1000225/S1100410) to the HAM6 sub-assy-load:  D1300122.

Note:  In D1300122, a D1700316 cable is called out here instead of D1000225.  Are these interchangeable?

[Confirmed w/ Hugh that he installed the regular D1000225s because we had limited supply of the D1700316 & they were used for VOPO.  Richard M. told Hugh the standard D1000225s were acceptable for the ZM1 suspension.]

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