1. LSC-March-20011  LIGO End to End simulation  Lock acquisition design »How to increase the threshold velocity under realistic condition »Hanford 2k simulation setup »Lock acquisition, real and simulated  In-lock state noise simulation »Seismic, thermal and shortnoise »Simulate sensitivity curve  Detector operation support  Future plan - LIGO I and advanced LIGO Status of End to End model LSC Meeting at LLO on March 16th, 2001 Hiro Yamamoto / LIGO Lab @ Caltech LIGO-G010176-00-E

2. LSC-March-20012 End to End simulation  Simulation engine - like matlab »Time domain simulation framework written in C++ »Tools for IFO simulation »Field calculation based on a time domain modal model »Basic tools ready  LIGO Simulation program - like m file of matlab »Han2k –suspended core optics with LSC (Matt’s code) –Customizable for 4k IFO by editing a database text file  Application for LIGO »LIGO lock acquisition design »LIGO base noise curve seismic, thermal and shotnoise

3. LSC-March-20013 Hanford 2k IFO Lock Acquisition  Matt Evans  Design of FP lock »realistic controller, smart logic  Han2k - LIGO simulation program built using e2e »scalar field model »6 suspended mirror »seismic motion  Data vs simulation

4. LSC-March-20014 Fabry-Perot ideal vs realistic ideal realistic Linear Controllers: Realistic actuation modeling plays a critical role in control design. V I 150mA

5. LSC-March-20015 Fabry-Perot Error signal linearization

6. LSC-March-20016 Hanford 2k simulation setup

7. LSC-March-20017 Automated Control Matrix System LIGO T000105 Matt Evans Same c code used in LIGO servo and in simulation

8. LSC-March-20018 Multi step locking State 1 : Nothing is controlled. This is the starting point for lock acquisition. State 2 : The power recycling cavity is held on a carrier anti-resonance. In this state the sidebands resonate in the recycling cavity. State 3 : One of the ETMs is controlled and the carrier resonates in the controlled arm. State 4 : The remaining ETM is controlled and the carrier resonates in both arms and the recycling cavity. State 5 : The power in the IFO has stabilized at its operating level. This is the ending point for lock acquisition.

9. LSC-March-20019 Lock acquisition real and simulated observable Not experimentally observable

10. LSC-March-200110  What’s new »Fully time domain »Full simulation of locked Interferometer »Based on “measured” signals, not on analytic formulas  Seismic noise »seismic motion + stack transfer function (Ed Daw) + pendulum  Thermal noise »wire and internal (Kent, Sam) »  Shotnoise »noise generated based on the input power on the photo detector »non stationary effect and mixing angle dependence calculated  Use “measured transfer function” to convert to sensitivity In-lock state noise simulation

11. LSC-March-200111 Noise of one mirror seismic & thermal Hz

12. LSC-March-200112 Average number of photons Actual number Photo detector by detector Detector noise Shotnoise (1) Off (2) Simplified (3) Full simulation

13. LSC-March-200113  L- control force for low frequency  Quad-demodulated signal from dark port for high frequency Simulated sensitivity by L- control and Quad asym

14. LSC-March-200114 Simulated sensitivity curve Hz L- control dark port error signal input power is 1W

15. LSC-March-200115 Shotnoise contribution Hz with shotnoise without shotnoise input power is 1W

16. LSC-March-200116 In-lock state noise simulation Commissioning support  Coupling of length and angular controls and actuation  Propagation of noises  Study of lock stability  Non stationary phenomena  Optimization of servo settings  …

17. LSC-March-200117 Future work LIGO I  Software / Physics »In-lock state noise –Seismic noise –Thermal noise –Generate combined noise »Simple 3D mirror »WFS »Validation of modal model code »Simple PSL/IOO for L+ feedback »Radiation pressure »Thermal effect »New optics model »Integration of MSE »Mirror aberration by higher order mode  Software / C++ »Parallelization using thread »Save & Load »Multiple time step »Improvements of tools –Macros, Funcs  System / LHO-LLO »Full 6x6 (3x3) stack –Including validation »IFO / site specific –Seismic motion –Mechanical properties –Optical properties

18. LSC-March-200118 Future work Advanced LIGO  Optics »Summation cavity of dual recycling configuration –Malik »Thermal lensing / thermo-elastic –Calculation of the (physical and optical) deformation of optics –Calculation of fields with those deformed objects –Melody  Mechanics »Simulation of quad pendulum –MSE vs matlab »Interfacing with existing tools