Projects by User Groups in Spain: Application to g-ray Spectrometry Begoña Quintana Arnés Grupo de Física Nuclear Universidad de Salamanca GEANT4 Workshop, Geneva 2002

Introduction Experiments with Ge detectors: a) nuclear structure (EUROBALL, AGATA, PRISMA); b) radionuclide analysis, background experiments Groups in Spain devoted mainly to radionuclide analysis. Our group also to optimisation of large devices via MC simulation GEANT4 Workshop, Geneva 2002

EUROBALL SIMULATION WITH GEANT3.21 GEANT4 Workshop, Geneva 2002

Code Validation Simulated response of Ge detectors to quantitatively calculate efficiency, coincidence-summing and self-absorption corrections (I<3%) in [20,2500] keV Very precise experimental results suitable for physics validation GEANT4 Workshop, Geneva 2002

Physics Problem Simple detector geometry GEANT4 Workshop, Geneva 2002

Physics Problem Physics processes into the crystal: fotoelectric, Compton (no polarized), pair production, e- energy losses, Ge X-rays (< 10 keV) production, Auger e-. Outside the crystal, also X-ray production, radionuclide decay, bremsstrahlung, interaction of muons and neutrons, mainly, with heavy elements... GEANT4 Workshop, Geneva 2002

Results with Geant3.21 “Effective” detector geometry: lack of precision in detector dimensions or in how physics is implemented? Added routine to deal with Ge X-rays Efficiency deviation < 3% in the [46,1800] keV energy range (also corrections) Geant4 simulations of Seville Group also by fitting parameters: same order of magnitude in efficiency deviations GEANT4 Workshop, Geneva 2002

Challenge No detector parameter fitting P-type detector response GEANT4 Workshop, Geneva 2002

Next Steps Comparison GEANT3.21 and GEANT4 results New simulation with GEANT4 without detector parameter fitting Determination of performance Building of user routines prepared to easily implement geometries and materials in run Validation via lab intercomparison GEANT4 Workshop, Geneva 2002