Peter has transitioned the LVEA to Laser SAFE

PSL tripped this past Saturday. HPO has been bypassed and powered down for water removal and dry-out in preparation for the 70W amp install.

PSL

    Starting 70W amp work after meeting.

Commissioning

    HAM6 looks good, DRMI was locked. Looking at HAM6 South door removal this week, as well as placing ISCT6 being placed just outside the cleanroom. Will capture SDF.

Vac

    MY CP4 work continues; craning, electrical, and piping work.

    More discussion on the HAM6 septum view port cover.

EX

    Activity will be ramping up at this end station, including: prepping cleanrooms, prepping weld room, PCAL alignment, ALS power supply, staging equipment, VE interlock.

Film crew will be on site Thursday Friday.

Will be going laser SAFE until we need lasers for commissioning. Work Safe!

Laser Status:
SysStat is good
Front End Power is 34.81W (should be around 30 W)
HPO Output Power is 29.17W
Front End Watch is GREEN
HPO Watch is RED

PMC:
It has been locked 1 days, 15 hr 1 minutes (should be days/weeks)
Reflected power = 3.255Watts
Transmitted power = 22.57Watts
PowerSum = 25.82Watts.

FSS:
It has been locked for 0 days 2 hr and 9 min (should be days/weeks)
TPD[V] = 0.7296V (min 0.9V)

ISS:
The diffracted power is around 2.7% (should be 3-5%)
Last saturation event was 1 days 15 hours and 2 minutes ago (should be days/weeks)

Possible Issues:
FSS TPD is low

I'll put in a Work Permit tomorrow that details the process of letting CP4 go "dry".  Starting from 75% full will give a little head start to the lengthly process.  Chandra R. has lots of activities related to CP4's decommissioning scheduled for this week so we don't have a lot of "wiggle room".  


This step may well result in CP4 level alarms tonight.  This is expected and is being monitored remotely. 

Having started 4 days later than originally planned combined with a (Kyle-typical) too conservative rate-of-rise (40C after 24 hrs.), I've decided to abort the low temperature bake exercise.  I had hopped to soak at 65C - 80C for a few days to see how the current iteration of heated zones (flexible heat wrap) behaved and also to dry out the wet fittings a little.  Though the individual components had been Class-Ad initially and redundantly vacuum baked after assembly, an unforeseen reconfiguration was needed that required venting the turbo+RGA assembly with "room air".  Additionally, the 10" gate valve (O-ring sealed) at CP4 was also exposed to wet air to facilitate the installation.  So, getting a useful "before" scan of CP4 would require some form of bake.  No worries.  A "before" scan would be interesting (but optional).  What will really matter is getting a sensitive "after" CP4 bake scan prior to combining it to the rest of the site.  This won't be a problem as we will have lots of time and the setup is now done.  

Notes:  
As found today, the turbo inlet pressure was 2.0 x 10-7 mbar while at 40C.  Also, the scroll pump seemed way too warm for not having a gas load.  Hmmm.....foreline leak? I didn't have a gauge on the foreline initially so I installed one today.  It showed 8.5 x 10-3 torr on the Tee at the scroll inlet which is ~7 ft. away from the turbo exhaust and 10 minutes after pumping the foreline back down.  Still, it isn't typical to run so warm without pumping gas.  For now, I setup a fan to cool the scroll.  

I'll be at Y-mid VEA making temperature measurements and/or adjustments or in the VPW tinkering with VBOC.  I expect to only be here 90 minutes or so.  Gerardo M. is my "phone buddy" and I'll make a comment to this entry when I am leaving the site. 

I came in to do some last DRMI/PRMI tests, and found the laser is off.  This happened about 4:15 am pacific time.  THe epics channels don't show any problems with the chillers, and it looks like the power watch dog tripped after the laser went off. (screenshot attached)

I plan to make a check of the (3) turbo pumps in the LVEA as well as the LVEA purge-air supply (a.k.a. the "Kobelco") in the Mechanical Room.  Following that, I'll be back and forth between the VPW (tweeking VBOC) and the Y-mid VEA doing work related to WP#7335.  I won't be operating pwr tools, using the crane or climbing on ladders.  Gerardo M. is my "phone buddy" and is aware that I am here and what I'm doing.  I'll text him at 3 pm or whenever I leave whichever comes first.  I'll also make a comment to this log entry when I leave.  

Terry, Nutsinee

Got some measurement of the EOT faraday isolator on the green path:

Over all transmission ~ 91% (S and P pol)

• 91% S-pol went through
• 91% P-pol rejected
• ~9% loss

Isolation ~ -26dB

Couldn't find a non-polarizing beam splitter for 532 so I used a dichroic beam splitter set at weird angle (~30 degree or so) to partially let light though. I used one of the precision photonics mirror found in the SQZ bay drawer to reflect transmitted light straight back into the faraday and measure the light that bounced back from the beam splitter. I couldn't measure the part of back reflected light that went though the beam splitter so I guesstimated the transmission knowing what came in and what gets transmitted on its way into the faraday. Terry thinks this number is disappointingly low, given the dodgy set up I'd take this number as an upper limit (in a sense that it can't get any worse). But again, given the nearly 10% loss maybe we just have a not-so-great isolator. 

Some recent modest ASC full data trend plots have shown gaps in the data with an accompanying popup error:

[Error] Purging failed. Increase 'Max drawing path length' in prefs.

It is not immediately clear what "purging" and "max drawing path length" mean, but if you increase it from the default of 20k to 100k the gaps disappear.

Attached is the 'gappy' plot with the popup, and the preferences with the increased max drawing path length