• Planned_Measurements_and_Procedures

This Page describes the forward plans and measurements to do with DC Readout/OMC at the 40m.

Re-establish the IFO state (ie, get back to where we were with respect to RF locking)

• MC beam
• imact on AS RF beamline; getting on to all the PDs and recommissioning the signals
• impact of new controls electronics on existing RFM / DAQ

Tweak the input mode matching telescope, to match the input mode to the average of the two arms rather than just the x-arm, as it is now.

Test/familiarize the new digital controls systems:

• Familiarize ourselves with the new MEDM screens, Rob will make them better & talk with Rolf about autogen

• Integration with the current RFM network, Dataviewer, DTT, and tds tools for scripting (all new stuff at 32kHz)
• Integration with the current LSC processor for global control (ie DARM on DC)
• Test control outputs (for DC biases/controls of all PZTs)
• Test dither outputs for all PZTs
• Test/characterize the ADCs and whitening filters, do a channel checkout

Commission the OMC

• (0) Instrument the OMC reflected beamline with QPD and camera and photodiode.

• (1) Find the OMC transmitted light on the AS table
  • Lock the bright michelson IFO
  • Sweep the cavity with triangle wave, maximize the transmission of
  • some peak by steering the PZTs, and find that on the AS table. Alternatively, sweep
  • the cavity, while rastering the TTPZTs over their full range at
  • four different frequencies, to find the transmitted spot. Then
  • set up the CCD camera, and route the video feed into the control room.
  (2) Lock the OMC to a TEM00 mode and commission the OMC-ASC dither system.
  • Once the dither system is working, mode match the IFO darkport beam to the
  • OMC by tweaking the Output Mode Matching Telescope. This should be trivial if
  • the dither-alignment system is working. Disconnect the picomotor.

Commission DC Readout

• (1) Establish DC Readout using a simple Michelson.
  • Handoff control of DARM to the OMC transmitted light. Measure both
  • inside and out-of-loop noise (phase noise), and compare with RF. Study
  • compensation for the quadratic portion of the error signal. Study noise
  • couplings for the two readout techniques (laser noise, alignment, ...?).
  (2) DC Readout with a Power-Recycled Fabry Perot Michelson
  • Strategy the same as (1), above, but we'll also have to perfect the
  • no-bang locking for this configuration along the way,
  • using 33 MHz RFPD at AS port.
  (3) DC Readout with Dual-Recycled Michelson Interferometer. (4) DC Readout with a Power-recycled RSE interferometer.

Comission DC ASC for full IFO

• This will involve stealing the current, mostly useless ASC system,
• and re-configuring it in the style of the new OMC computer. Thus, it
• will have inputs from some diodes around the system (probably network
• traffic from LSC diodes will be fine, but maybe we'll also want to retain
• some QPD signals), and a sizable set (14?) of digital lock-in systems, with
• input and output matrices, that will allow us to route dither/feedback signals
• to all the suspension ASC inputs.

Squeezing injection optics installation and checkout.