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: 4585     Entry time: Fri Apr 29 03:39:49 2011
Author: Koji 
Type: Summary 
Category: LSC 
Subject: Cavity lengths 

I tried the idea that the PRC can resonate f1 and f2 at the same time if the arm gives the reflection phase to f1 and f2 with the ratio of 1 vs 5.

The details are described on wiki. The point is this removes all of the PRC/SRC/asymmetry mumbo jumbo.

The calculated cavity lengths for f_mod of 11.065399MHz are:

  • Arm Length: 37.7974 [m]

  • PRC Length: 6.7538 [m]

  • SRC Length: 5.39915 [m]

  • Asymmetry (lx-ly): 0.0342 [m]


Here is the actual values derived from the photos.

  • Arm Length: 37.54 [m] (0.26m too short)

  • PRC Length: 6.760 [m] (6mm too long)

  • SRC Length: 5.415 [m] (16mm too long)

  • Asymmetry (lx-ly): 0.0266 [m] (8mm too long)

ELOG V3.1.3-