andreas freise ilias wg1 meeting cern (29-mar-07) geo 600 simulation group

Andreas Freise

ILIAS WG1 Meeting

CERN (29-Mar-07)

GEO 600 Simulation Group

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


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

InterferometryR+D


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


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


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 ….

http://www.sr.bham.ac.uk/dokuwiki/doku.php?id=geosim:home


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)


OptoCad: Alignement tolerancing of the LISA Pathfinder optical bench (Gudrun Diederichs)


OptoCad: Alignement tolerancing for LISA Pathfinder


OptoCad and Finesse


Simple Two-Mirror Cavity

Finesse output


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


GEO Commissioning


Shotnoise

New Finesse command 'qshot'

New algorithm to compute shotnoise for N carrier/ modulation fields and M demodulations (paper submitted)


The missing factor of two

The modelled shotnoise did not match the measuredsensitivity. Often we were apparently missing a factorof two or sqrt(2). Do we understand why? YES


Adding Phasemaps to Finesse


Finesse with Phasemaps

Analyse the effectsof mirror surfacedefects

Study aperture effects(clipping)

Simulate flat beams


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 testednightly


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) ….


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


end


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


The GEO Collaboration LISA is a mission to detect and observe gravitational

waves



waves

andreas freise ilias wg1 meeting cern (29-mar-07) geo 600 simulation group

Documents

geo geo

geo experimentslinks

geo identitytest

optical layout geo

frequency domain geo

simulation programs

finesse simple

new finesse command