40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  40m Log  Not logged in ELOG logo
Message ID: 9555     Entry time: Tue Jan 14 19:10:51 2014
Author: Gabriele 
Type: Summary 
Category: LSC 
Subject: PRC length measurement 

 [EricQ, Gabriele]

We could carry out the measurement of PRC length. The AS110 photodiode was plugged into REFL11. So REFL11 is giving us the AS11 signal. Here is the procedure.

  1. Lock MICH.
  2. Add a line in MICH (amplitude 20000 counts)
  3. Tune AS11 demod phase to have the line in I.
  4. Change the demod phase by steps of 1 degree around the rough optimum, taking one minute of data at each point
  5. Lock PRMI on sidebands
  6. Add a line in MICH (amplitude 500 counts)
  7. Tune AS11 demod phase to have the line in I.
  8. Change the demod phase by steps of 1 degree around the rough optimum, taking one minute of data at each point

We repeated the same measurement also using AS55, with the same procedure.

Roughly, the phase difference for AS11 was 11 degrees and for AS55 it was 23 degrees. A more detailed analysis and a calibration in terms of PRC length will follow.

ELOG V3.1.3-