J. Freed, J. Kissel, J, Wright, F. Clara

Continuing from 90621 (Notes are stored here). Today we brought the SPI picomoters into play, got caught up on our backlog of alogs, and began probably our toughest opical alignment during install. The periscope...

In order we did:

• Noted some alignment drift as ISI HAM2 was unlocked and damped overnight,
• Got picomotors on SPI overview
• Turned on and made functional IFO demod system, got a live measure of contrast
• Found that FBR_PWRIN_REF was saturating / oscillating 90642
• Turned on HAM2 ISIJ M_C1 picomotors
• Was in ISI_DAMPED_HEPI_OFFLINE all morning, and everything worked excellently
• In Control Room – used M_M1 picomotors to center on HAM2 ISIJ QPD A, easily recovering the M_M1 to M_C1 alignment due to HAM2 unlocking with picomotors. 
• Confirmed M_C1 picomotors were alive, but were getting confusing results from ISI HAM3 QPD B.
• In chamber – used M_C1 to center beam on M_M5
• Tried physically aligning M_M5 to steer beam on to QPDB, ran into issues with irreproducibility of adapter position within the IXM100 mount. Will have to trial, error, and get lucky to get the alignment right.
• Some discrepancy between physical spot position on QPDB vs. what CDS says, also when beam is on one quadrant it’s saturating that quadrant.
• Conclusions:
  • Picomotors are alive, exactly what we need, plenty of range and coordinate system transformations all make sense
  • IFO REF efficiency drift is ominous 90644; that plus limited time resolution of beatnote in CDS makes maximizing efficiency with alignment a challenge so far 
  • We *need* a re-design of the periscope mount for the future – need to design a periscope mount that has 3-axis rotation capability (pitch, yaw, *and* roll of the mount)
  • Likely need to reduce the transimpedance on the QPDB segments channels