1. Automatic Alignment Control scheme for Advanced Virgo
M. Mantovani, for the ISC group
M. Mantovani ISC meeting 13 Mar 2009

2. Alignment conceptual design
Evaluation of Anderson vs. Ward technique
MSRC:
feasibility of noise evaluation due to high order modes
NDRC:
no extra d.o.f to control (there are no global error signals available)
dynamic range is different due to different beam sizes and extra mirrors
Steady state sensing configuration
mod. freq., compatibility with quadrant freq. resp., error signals
M. Mantovani ISC meeting 13 Mar 2009

3. Alignment conceptual design
Steady state control configuration
radiation pressure mitigation
Noise performance
coupling to DF, electronic noise
Modulation Frequencies
Compatibility with EM environmental noise
Sidebands on sidebands: possible or not?
radiation pressure
definition of Sidles-Sigg modes
M. Mantovani ISC meeting 13 Mar 2009

4. Alignment design specifications
Beam/quadrant ports definition
noise perf., DC powers
Angular accuracy specification
RMS, beam jitter, LC specs
M. Mantovani ISC meeting 13 Mar 2009

5. Milestones & Concerns Single cavity alignment Man Power:
VIR-109A-08 to be rechecked with the final optical parameters
Man Power:
At least a physicist or an engineer is needed full time
M. Mantovani ISC meeting 13 Mar 2009

6. Concerns: Simulation tools: Optickle: Finesse:
radiation pressure present (thus is the only one that can be used for the moment)
any possibility to simulate static misalignment
any possibility to evaluate the presence of offsets
any possibility to evaluate the AA error signal linear region
No yaw d.o.f.
Finesse:
no radiation pressure
M. Mantovani ISC meeting 13 Mar 2009