IO optic inspection identifies L1 as having areas of contamination or damage to the coating

I inspected the optics in the IO path on the PSL, and discovered that L1, the first lens after the EOM, has one easily identifiable area on the surface near the EOM, and two easily identifiable areas on the surface away from the EOM, that are contamination/damage to the coating.  Two areas are at or close to the center of the optic, the other area is about 1/8th of the optic that is covered in what looks like a thick film.

The first three images attached are of L1:

1. L1, looking toward the EOM, this is the "filmed" area, it's on the surface that's closer to the camera, with a reflection from the other side of the lens.  There are circular marks through the film and this looks like someone used a wipe to clean the optic, possibly for dust, and happened to clean off a bit of film.  The film was only visible to me with the flashlight.
2. L1, looking toward the EOM, and the "filmed" area is on the left side, there's a large bright white spot and reflections that are from the flashlight above the filmed area, and to the right there is a small area of contamination/damage that looks somewhat like a ring.  This is on the surface that's closer to the camera, and it's close to the center of the lens.
3. L1, looking toward the EOM, showing the contamination/damage that's on the surface that's closer to the EOM, on the EOM side of the lens.  This is feature has very clear edges, and is close to the center of the optic.

With L1 being very close to the EOM output, I was not able to see the output face of the EOM crystal, so this still needs ot be inspected, and the best opportunity to do this is when L1 is replaced.  The EOM crystal surface sits within a few mm of housing aperture, so it can be seen through the EOM housing.

The last two images attached are of the EOM output aperture and crystal:

1. the EOM output aperture from the -Y side of the PSL table, where the output aperture faces in the +X direction.  This image shows the crystal without IR light, so the crystal is seen through the EOM housing and is dark, and at this viewing angle, the right front edge of the crystal face is visible.
2. the EOM output aperture from the -Y side of the PSL table, where the output aperture faces in the +X direction.  This image is from a similar viewing angle with IR light, taken with an IR sensitive camera, and there's a back reflection from L1 that is clipping on the EOM housing, and through the aperture, the right front edge of the EOM crystal is seen as a vertical line, which matches it's location in the first image.

I talked to Daniel, and he saw the images, and we talked about replacing this lens after recovering the IMC, so next week or later, and before O3.

Pumping Y-end

Chris S., Gerardo M., Kyle R.

We put the north door back on BSC10 this afternoon.  Particles counts were < 100 for the displayed sizes at the time the soft cover was removed. 

Inspection revealed two areas of missing viton from the outer O-ring.  Viton was not stuck to the door in the corresponding area of the door flange thus indicating that, most likely, this had happened in the past.  Since this outer O-ring had been leak tight leading up to this most recent door cycle, we went ahead and reused this blemished O-ring -> but helium leak tested this shortly after pumping down the annulus volume - just to be sure :)

Measured dew point of purge air entering the Y-end was -45C and exiting was -32C (just prior to start of pump down).   

With the Y-end vacuum volume having been "blown down" to atmospheric pressure and 15 minutes after starting the pump down I noticed PT410's indicated pressure was >820 torr -> Gerardo was then able to adjust the "ATM" potentiometer on PT410 such that it then agreed with the pirani gauge at the turbo inlet. 

 

Summary of PSL Work Today

J. Oberling, P. King, J. Bartlett, R. Savage

Following on from yesterday's plumbing work, today we concentrated on recovering the 35W FE, the 70W amplifier, and completing the remaining items from FRS 10753.

This morning, Peter recovered the 35W FE without much fuss and also installed the new solid block base for the 70W amplifier.  He and I recovered the 70W amplifier, also without much trouble; we tweaked beam alignment for a compromise of power and beam quality and were able to return the beam very close to what it was before the new base installation.  We then proceeded to take a beam propagation measurement to use in PMC mode matching.  This was necessary as the installation of the new amplifier base resulted in the 70W amp moving closer to the PMC by ~1/2", which in turn will have an effect on PMC mode matching.  At this point we broke for lunch.

The final part we needed to complete the chiller work (an adapter for installation of a throttling valve on the supply line out of the chiller) arrived today, so this afternoon Jeff and I installed the valve.  After leak checking and leak fixing, we fired the chillers up and all was well.

Rick and I then balanced the flows and pressures out of the crystal chiller.  To do this we completely opened the new external bypass Jeff installed a couple months ago and completely closed the chiller's internal bypass; this internal bypass being open was what was causing the very high operating pressure (70 psi!) for the system.  In this configuration the chiller had a flow of 38 lpm.  We then used the throttling valve to reduce the overall chiller flow to 18.7 lpm (keep in mind that the external bypass was still completely open, so almost all of that water was flowing through the bypass, not the PSL manifold).  We then slowly closed down the external bypass to provide a pressure drop for the PSL manifold, therefore letting water flow through the various cooling circuits.  As it stands right now, the flows and pressures of the PSL cooling system are:

• Manifold inlet pressure: 1.7 bar (24.7 psi)
• Manifold outlet pressure: 1.4 bar (20.3 psi)
• 35W FE flow: 1.2 lpm
• 70W amp flow: 1.2 lpm
• Power Meter flow: 1.2 lpm
• Chiller flow: 18.7 lpm

Please keep in mind that most of that chiller flow is still going through the external bypass.  This is an absolutely huge improvement as prior to this work we were running with a manifold inlet pressure of 70 psi (!!!).  At this point I returned to the enclosure to return it to "Science Mode" so Robert can assess if all of this plumbing work made a difference in PSL table vibration.  Tomorrow we will begin mode matching the PMC, with our goal being >50W transmitted power with the ISS ON.

Front end and neoVAN flow rates for the past day.  Clear reduction of flow rates observed
after the plumbing work.  Still settling out I would think.  The 4 excursions in the front
end flow rate are probably bubbles making their way through the system.

VOPO Alignment and Mode Matching

[Sheila, Fabrice, Nutsinee, Terry, Haocun]

Summary:

We have OPO coupling 89% 00 mode, alignment >~95%, mode matching >~95% and polarization mode ~2%.

I will add more details with numbers later.

CDS Maintenance Summary: Tuesday 13th November 2018

h1lsc code update

Daniel, Dave:

A new h1lsc model was installed. DAQ restart was required.

Slow Controls, new C1-PLC2 code

Daniel, Dave:

a new h1ecatc1plc2 was started this morning. Its INI file was updated in the DAQ. Its SDF system was restarted (h1sysecatc1plc2sdf) and the new channels were ACCEPT-MONITORED.

WP7098 h1tw0 offload

Dave:

The offloading of raw minute trends from h1tw0 to h1ldasgw0 completed this morning. h1nds0 was reconfigured to serve these data from their new location.

EY Dolphin crash.

At 11:04 for reasons unknown, EY suffered a Dolphin crash. It is unsure if it was related to BSC10 in-chamber work. All models were restarted on h1susey, h1seiey and h1iscey.

TMSY ring up.

Betsy, Hugh, Ed, Dave:

over the lunch hour TMSY rang up and tripped the SWWD. Investigation is continuing.

DAQ Restart:

Dave:

For h1lsc, h1ecatc1plc2 and h1nds0 changes.

 

Shift Summary - Day

TITLE: 11/13 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
INCOMING OPERATOR: None
SHIFT SUMMARY

LOG:

16:20 HAM2 SEI re-isolated

16:22 re-isolated BS sei

16:30 Betsy and Fil out to EY

16:57 Jason out to PSL

17:07 Richard to Ends to check grounding

17:15 Norco on site for LN2 delivery - #76 CS-X

17:16 Laser Hazard

17:22 Sheila out to LVEA- joining Terry at HAM6

17:31 Norco on site for LN2 delivery - #79 N-MX

18:08 Nutsinee out to LVEA - HAM6

18:09 Marc out to LVEA - HAM6 and PSL/ISC rack area WP#7940

18:15 Set EY sei for in-chamber work - ISI to Offline_HEPI on ... tripped anyway

18:38 Dave B resetting LSC and then DAQ (in 5)

19:09 EY system crash - Dave B investigating the cause

19:15 Peter back

19:25 Jason back for lunch

19:18 Richard out to EY to investigate sys crash

19:49 Richard back

19:58 Dan and Dan out to LVEA - ITMY Hartmann table

20:20 Pepsi on site

20:55 Sheila, Terry, Haocun, Fabrice and Nutsinee back

21:15 Dan and Dan back

21:35 Jeff B and Marc P out to LVEA - Jeff for tools; Marc for a chassis

21:40 Jeff back

21:46 Sheila out to LVEA - HAM6

21:52 Cheryl out to PSL

21:56 Fil out to CER

22:03 Terry out to LVEA - HAM6

22:06 EY ISI re-isolated after stage 2 trip

22:23 Nutsinee out to LVEA - HAM6

22:41 Peter back

22:51 Marc back

23:03 Richard out to CER

23:03 Chris S back from EY - doors back on

23:08 Chandra out to EY

23:16 Richard back

23:49 TVo out to LVEA - ITM OpLevs showing no sum

PFD and IQ Demod Upgrades complete in Corner

The phase frequency discriminator (PFD) and both IQ demodulators in the corner have been upgraded with the local oscillator (LO) modification and in the case of the IQ Demods their power interface board has been upgraded to allow more readbacks.  End Stations and and some spares remain to be upgraded.

WP7940

E1800234

S1000771, S1000772 Demods

S1000761 PFD (this was completed here ALOG43041)

 

ETMY ESD LR Attempted repair

FRS 10543

Verified ALS and PCAL lasers were keyed off.

~9am - Kyle, Gerardo, Chris Removed last 4 WBSC10 door bolts and removed the door

~9:20am - In-air, prior to anyone entering chamber, Fil performed HiPOT testing - ALL 5 ESD connections PASSED the 1kV test

~9:30am - Travis and Betsy entered chamber, locked the PUM mass, removed the CC horizontal witness wafer from under the QUAD

Test for continuity of all 5 ESD connections with Fil from the feed-through to the solder joints at the AERM (copper wire grounded to QUAD structure leg) - ALL 5 PASSED

~9:45am - Decided to repair LR connector anyway due to questionable hardware in the connector (incorrect sized inner pins)

ISI and Suspensions unlocked (except PUM carefully)

Disconnected connector after removed from PUM clamp

Wiggle test of pins and receptacles of the ESD connector - all seemed good, strong, not pushed in...

Cut off LR and performed retermination with all new parts per E1800147-v3, including new center pins, and proper crimping.  Half of the work was performed wth my right and Travis' left hand since the short pigtail off of the AERM out the back of the QUAD had very little working room.

NOTE - Although there looked to be some crimping, Fil could easily pull off the outer sleeve PN-100909 from the receptacle.  We did not see any other short symptoms such as wire fragments, over crimping, etc.  (And, it passed today.)

~11:10am Finished retermination of LR and reassembly of connector, remounted in clamp, unclamped PUM, freeing ETMY reaction chain fully

~11:20am Rechecked continuity in same manor as above - ALL 5 ESD connections PASSED, Rechecked HiPOT at 1kV - ALL 5 ESD PASSED

~11:30am Gave the ETMy a quick N2 blow (barrel, gap, HR, AR as best we could without ACB swing back, etc. Saw the "typical" amount of particulate and features.

~12pm - Decided with Daniel to not "fix" remaining 4 connectors because 1) it was taking much longer to do with everything floating and 2) they aren't broken

Started transfer functions of ETMy Main and Reaction, and TMSy  - all look ok

~1:30pm Hunted for chamber closeout signouts from cog engineers.

~2pm Door going on

TCS Chiller Water Level Top-Off - Weekly FAMIS#11465

Jeff B handled this. No water was needed as chillers are currently OVERfilled.

Reminder that new wide-range gauges max out at 750 torr

Can't see purge pressures via these gauges.  Could be misleading if this detail gets forgotten.  

EY models crashed at 11:04

At 11:04 most models stopped running at EY. We are currently unsure if this is a Dolphin crash or caused by electrical work at EY.

Interestingly in addition to the expected corner station IPC errors, all SEI frontends have an ADC error on their IOPs.

Shift Transition - Day

TITLE: 11/13 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    Wind: 6mph Gusts, 4mph 5min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.25 μm/s
QUICK SUMMARY:

14:15 Peter out to PSL - remounting 70W amp

14:30 Chris S out to LVEA - HAM6 scaffold

15:07 Chris back

15:30 Bubba and Chris out to LVEA- set HAM6 end cap door down on pallets'

16:00 Jeff B out to LVEA

 

Comparing DARM spectra and range integrands for 80, 83, and 83 Mpc locks

Sheila, Georgia

I had a look back at a few locks on Friday and Saturday, to compare in which frequency bands we made improvements. On friday we went from roughly 80 Mpc (Friday morning), to roughly 83 Mpc (Friday evening), for reasons we're not really sure of. With Saturday's power up to 30 W (edit: note the lock stretch I looked at the IMC_PWR_IN reads 26 W rather than 30 W) the range increased to ~93 Mpc.

First attachment left plot shows the DARM spectra, and the right plot shows the cross correlation spectra, red is a ~93 Mpc lock, blue is a ~83 Mpc lock, mint is a ~80 Mpc lock. Note the 93 Mpc lock I chose is before we ran A2L and brought the low frequency noise back down.

Shot noise improves with increasing power, but between all 3 locks we also see an improvement in the uncorrelated noise. Going from 80 Mpc to 83 Mpc this improvement is seen from 60-250 Hz; going from 83 to 93 Mpc the improvement is mostly in the 90 - 200 Hz region. I had to hunt around to find long enough lock stretches with no glitches, and I have belatedly realised that the particular 93 Mpc lock I picked out is while Stefan and Peter were increasing the OMC DCPD current, which might contribute to this difference.

I used Sheila's range integrand calculator to compare the different frequency-bands' contributions to the overall range. The top plot of the second attachment shows the DARM spectra again, and the bottom is the integrand. Ignore the sharp dips - between these three locks we had different combinations of calibrations lines turned on and off. The third attachment shows the cumulative range as a function of frequency for these three locks, and the difference in the cumulative ranges going from 80 to 83 Mpc, and from 83 to 93 Mpc. These show most of the improvement going from 80 to 83 MPc was in the 35 - 100 Hz band, while powering up it was in the 80 - 300 Hz region. The improvement in shot noise above 250 Hz doesn't contribute very much to the range.

For reference, the lock times I used started at:

~80 Mpc, t0 = 1225827083

~83 Mpc, t0 = 1225864223

~93 Mpc t0 = 1225937394

Prepare new LSC model for REFL_B

The LSC model has been prepared to accommodate the new REFL_B photodetector. This includes

• DC readback through second port on LSC PD interface chasses in ISC-R1.
• This detector has its own RIN module.
• I/Q readbacks of both IMC and LSC-REFL_B using the new whitened DAQ interface of the 2-chn demodulators.
• Renamed REFLAIR_A_RF-ERR from the summing board into REFL_B_RF_ERR, so the I signal can be added to the CM board.
• Removed obsolete ALS-C_DIFF_A_RF_ERR.
• Removed obsolete communication module with EtherCAT.
• Added back Extra_AI_3, Extra_AI_4 and Extra_AO_3.

A corresponding change to the TwinCAT code has also been prepared.

WHAM6 Vent Activities

Chamber Cleaning starting before 8 (Christina, Vanessa, Karen.)  VE venting volume around 8am (Chandra.)  Venting completed and East Door removed ~9:30, Kyle Gerardo, Bubba.) Dust Monitor counts 30 & 30 in clean room just before door removal.  After removal, Dust counts in chamber 10 & 10.

Fiber change out from ~10am to 12:40: Old fiber & Feed Thru removed, Test fiber/FT installed/removed, Real deal fiber/FT installed.  Feed Thru bolts remains just snug (Sheila, Fabrice, Haocun, Nutsinee.)

SQZ has gone hazard and work continues.

BruCo scan for ~100 Mpc time

• Updated BruCo scan using the best sensitivity so far (reporting above 100 Mpc), between 1226014475 and 1226014475+400s

https://ldas-jobs.ligo.caltech.edu/~gabriele.vajente/bruco_1226014475/

• Below ~17 Hz, dominated by DHARD pitch and yaw

• INP1 and PRC2 yaw between ~15 Hz and 30 Hz. This coherence is seen also in most of the REFL WFS and most interestingly in some IMC transmission signals, like for example the ISS second loop QPD. I suspect this is an indication of real input beam jitter. Incidentally, sidebands around the 60 Hz line are also coherent with INP1 and PRC2

• There is some interesting coherence with OMC_A_YAW_OUT, but this might be related to the DHARD motion

 

• at the time, there was a large PCAL line at about 35 Hz, and a lot of coherence with PCAL signals, not only at the line both also broadband. I'm not sure if this happens in the normal state or if there was some injection going on.

 

• SRCL noise is quite close to the sensitivity between 20 and 150 Hz. PRCL is also close.

 

• A few peaks are coherent with the PSL periscope accelerometer (about 177 Hz, 223 Hz, 483 Hz, 542 Hz)

Fishy HAM3 ISI sensors (Peter, Keita)

I was looking at the time when all ISIs were damping after yesterday's earthquake near Iceland.

I looked at the CPS to GS13 sensor to sensor response (e.g. CPS V1 to GS13 V1 etc.) to find out that HAM3 V2 CPS to GS13 transfer function looked completely different from everything else, and that this could be amplitude dependent.

In the first attachment, left is HAM3 and right is HAM2. HAM3 V1, V3, HAM2 V1, V2 and V3 are all look similar, but the Q of HAM3 V2 TF is much lower even if you only look at frequencies with reasonable coherence.

The second attachement is Jim's injection TF (alog 45134) with rearranged panels etc. to see the same quantity as my plots. Only HAM3 sensors are plotted. Interestingly, all TFs are similar but they are all totally different from my first plot in amplitude.

For example, just look at both plots at 1.3Hz or so (vertical markers in my plot) where the coherence was decent. Jim's GS13 amplitude is ~500 times as large as mine, but CPS is only 50 times as large.  As a result Jim's HAM3 V1, V2, V3 TF are about 20dB larger than my HAM3 V1, V3, HAM2 V1, V2 and V3.

It seems as if the GS13 response might be dependent on the excitation level, and that the small amplitude response of HAM3 V2 is very different from others.

The last attachment is the same as the first one, except that the first one was 2 hours after the EQ, this is right after.

It would be useful to repeat Jim's measurement with smaller excitation at some point.