Reports until 12:19, Friday 23 March 2018
H1 SEI
hugh.radkins@LIGO.ORG - posted 12:19, Friday 23 March 2018 - last comment - 15:05, Friday 23 March 2018(41127)
WHAM6 ISI Update & Status--ISI currently Balanced and Locked on Stops

Corey & I managed to milk the new V3 sensor cable through a new length of copper braided shield.  We had a 'fid' to help but more than two hands was a big factor as well.  We (I) was unable to get the too large a zip tie snug enough around the cable to hold the braid in position but only at the sensor end.  At the BNC connector end back at the feed thru, we could get all our hands in play and that one is secure.  I have smaller peek zip ties coming from Accu-Glass arriving next week and if they can be ClassA'd in time, we'll use those.  Otherwise we'll have to take the sensor off the platform and snug the tie as we did at the other end with more hands.  I was worried about damaging the cable at the sensor where we can't get enough hands into play to make sure nothing but the zip tie gets reefed on.  The big zip ties just require too much force to close tight enough.

We (I) still need to change the conflat gasket back at the feed thru, as well as the above mentioned cable tie job--next week.

And of course good spectra and any balancing if SQZ crew changes the payload.

We left the ISI locked.

Old Corner 3 Vertical CPS sensor SN 12023; new SN 12015.

Addendum: Since we had already reset the V3 sensor gap, we decided to re-gap what needed it.  The H3 CPS was over 6000 counts and that was the hardest one to access, The other two horizontal sensors were over 1000 counts so we did those too.  For the verticals, we redid V1 which was over 1300cts.

We then did an unlock/relock test and saw that the local verticals shift 200 or less counts whereas the horizontals shifted between 1600 to 2200 counts.  Have to move the lockers to fix that.  Naturally, in the cartesian basis, X Y & RZ have the largest shifts, namely 35000, 75000, & 16000 nanos while Z RX and RY shifted just 3600, 1400, & 5800 nanos.  Resetting the sensors of course require resetting the Isolation Targets--done.

Addendum II: I will put actual redlines on D1201388 but just to put it here in case anyone thinks of a problem, we ended up with 110kg more counter weight than the plan expected by SYS--that's an awful lot of mass the plan was missing.

Comments related to this report
corey.gray@LIGO.ORG - 15:05, Friday 23 March 2018 (41131)SEI

Attached are some photos from today's CPS "vascular surgery" work.  The photo names summarize what's going on.

(Also attaching a selfie of Hugh & myself after today's work.  March & April are respectively our 20-Years-With-LIGO-Anniversaries.  Fitting that we got to do some SEI work together this last week.  LIGO Seismic Bros for Life!)  🤓  [thumbnail is upside down, but full image is good.]

Images attached to this comment