GEO 600 Simulation Group

Andreas Freise

ILIAS WG1 Meeting

CERN (29-Mar-07)

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 A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 2

The GEO Collaboration

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

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 A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 4

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 Slide 5 A. Freise ILIAS WG1 - CERN - 29/03/2007

The GeoSim Website

   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 …. A. Freise Slide 6 ILIAS WG1 - CERN - 29/03/2007

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) A. Freise Slide 7 ILIAS WG1 - CERN - 29/03/2007

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

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

OptoCad and Finesse

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

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

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 A. Freise Slide 12 ILIAS WG1 - CERN - 29/03/2007

GEO Commissioning

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

GEO Commissioning

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

Shotnoise

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

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 A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 16

Adding Phasemaps to Finesse

A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 17

Finesse with Phasemaps

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

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 A. Freise ILIAS WG1 - CERN - 29/03/2007 Slide 19

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) ….

A. Freise Slide 20 ILIAS WG1 - CERN - 29/03/2007

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 A. Freise Slide 21 ILIAS WG1 - CERN - 29/03/2007

end

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

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 A. Freise Slide 23 ILIAS WG1 - CERN - 29/03/2007

The GEO Collaboration

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

The GEO Collaboration

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

The GEO Collaboration

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