Length Sensing and Control Design
This page discusses the design of the LSC system of the 40m Upgrade
Ports
The Power Spectrum for each port is provided. From that we identify the optimum sensing signals.
[...]
Sensing Matrix
For locking, the baseline plan is to use the same error signals of AdvLIGO:
DOF |
Signal |
CARM |
REFL_I1 |
DARM |
AS_DC |
PRCL |
POP_I1 |
MICH |
POP_Q2 |
SRCL |
POP_I2 |
In case that 3f signals will be used for lock acquisition, as a result of Optickle simulations, we propose the following sensing matrix:
DOF |
Signal |
X |
POX |
Y |
POY |
PRCL |
REFL_32I |
MICH |
REFL_31I |
SRCL |
REFL_32Q |
[...]
Cavity Absolute Lengths
Arm Cavities
Antiresonance conditions fro both sidebands [...]
=== Schnupp Asymmetry == Arguments on the Schunpp asymmetry design;
- dependence on the asymmetry of central cavity's coupling
- dependence of sideband output power ("throughput power" - K. Arai) to asymmetry
- different designs for different PRMs (initial, temporary 10%; final 5.5%)
- guidelines to change the asymmetry in different circumstances (alignment, etc.)
- [...]
Power Recycling Cavity
- ideal lengths
- lengths corrections
- [...]
Signal Recycling Cavity
- ideal lengths
- lengths corrections
- [...]