1. Andreas Freise ILIAS WG1 Meeting CERN (29-Mar-07) GEO 600 Simulation Group

2. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 2 Simulation Work in GEO  GEO in this sense is not GEO 600 but the people in GEO related research groups  Simulation work consists of:  Theoretical understanding of the physics  Coding the physics (algorithm development)  Coding, maintaining, documenting software  Using simulations to produce modelled data (commissioning, detector design, table-tops, …  Understand more about the modelled experiment from the modelled data

3. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 3 The GEO Collaboration Suspension Development Laser Development Squeezed Light R+D GW Source Modelling Detector Commissioning Laser Development Data Analysis LISA Instrument Development Design of future GW Detectors Interferometer Prototypes New Materials R+D Interferometry R+D

4. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 4 The GEO Collaboration  Relatively small collaboration  Entangled with several large projects  Subgroups develop automatically  Possible Remedy:  Create topic based groups  Members are contact points to the various activities  Strengthen and develop a GEO 'identity'  Test in progress: the simulation group

5. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 5 The GEO Simulation Group  Members (as of 22.01.07): Andreas Freise, Stefan Hild, Kentaro Somiya, Sabina Huttner, Roland Schilling, Paul Cochrane, Jan Harms, Gudrun Diederichs, Simon Chelkowski, Antonio Perreca, Jonathan Hallam, Oliver Bock  Meetings : 16.01.07 (Hannover), 13.03.07 (Hannover)  Resources: Website (Wiki), mailing list, svn repositories

6. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 6 The GeoSim Website  www.sr.bham.ac.uk/dokuwiki/doku.php?id=geosim:home www.sr.bham.ac.uk/dokuwiki/doku.php?id=geosim:home  A public Wiki with restricted write access  Hosts  Meeting dates  Talks of past meetings  References to GEO experiments  Links to simulation programs and software tools  Summaries of current or open tasks  ….

7. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 7 Code from the good old days  OptoCad  2D CAD program that traces Gaussian beams through an optical layout (GEO, VIRGO, LISA)  WaveProp  FFT propagtion code (somewhat like DarkF) (GEO)  LISO  Numerical electronic circuit simulator, specialised tool for building electronic filters  Finesse  Numerical Interferometer Simulation, uses Hermite-Gauss modes in the frequency domain (GEO, LIGO, VIRGO, TAMA)

8. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 8 OptoCad: Alignement tolerancing of the LISA Pathfinder optical bench (Gudrun Diederichs)

9. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 9 OptoCad: Alignement tolerancing for LISA Pathfinder

10. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 10 OptoCad and Finesse

11. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 11 Simple Two- Mirror Cavity Finesse output

12. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 12 Finesse: Current Activities  GEO commissioning  Using Finesse to 'debug' GEO by matching simulations to experimental results  Maintain a configuration file which is in sync with GEO reality  Quantum noise extension  For the design and commissioning of future detectors we need a proper description of quantum noise  Implementation of quantum noise is 50% complete  Adding new features  Phasemaps, Matlab interface, New detector types  Testing and code documentation  Unit tests, Code cleaning, Doxygen documentation

13. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 13 GEO Commissioning

14. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 14 GEO Commissioning

15. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 15 Shotnoise New Finesse command 'qshot'  New algorithm to compute shotnoise for N carrier/ modulation fields and M demodulations (paper submitted)

16. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 16 The missing factor of two The modelled shotnoise did not match the measured sensitivity. Often we were apparently missing a factor of two or sqrt(2). Do we understand why? YES

17. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 17 Adding Phasemaps to Finesse

18. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 18 Finesse with Phasemaps  Analyse the effects of mirror surface defects  Study aperture effects (clipping)  Simulate flat beams

19. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 19 The Finesse Code  Code is being re-organised and cleaned (Paul Cochrane)  It is now hosted in a svn repository and is currenlty changed regularly by three developers  Extensive code documentation via Doxygen  Manual (also extensive) is supplemented by in-depth explanations of GEO input files  Started to introduce unit tests of single functions: about 50% of the code base (43000 lines) is tested nightly

20. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 20 New Activities  LISA BBO Simulator (Jan Harms)  Thermal effects via FFT simulations (Jerome Degallaix)  Non-linear cavity simulator (Nico Latzka)  Simulating mirrors as elastic deformable objects (Yanbei Chen)  AdLIGO, Optickle (Kentaro Somiya)  ….

21. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 21 Conclusion  New GEO Simulation Group has been started  So far it works very well and has initiated or vitalised several activities related to GEO 600 and/or simulations  The group aims at forming a communication hub inside the GEO collaboration  This will also benefit the links between GEO and other projects  Link of the GeoSim meetings with LSC meetings planned

22. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 22 end

23. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 23 GEO Commissioning  GEO optical layout with OptoCad  Stores the location of the optics (lengths, angles)  Is used to understand spurious beams, etc.  Finesse input file for GEO  Computes control signals and transfer functions  Used to compute noise couplings and the detector sensitivity  WaveProp for thermal lensing  Is used only for special task which require a time-domain or FFT approch  LISA is a mission to detect and observe gravitational waves

24. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 24 The GEO Collaboration  LISA is a mission to detect and observe gravitational waves

25. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 25 The GEO Collaboration  LISA is a mission to detect and observe gravitational waves

26. A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 26 The GEO Collaboration  LISA is a mission to detect and observe gravitational waves