1. 19th July 2002, Salamanca 1 Efficiency calibration of a Germanium gamma-ray detector using GEANT4 * Dpto. Física Atómica, Molecular y Nuclear ** Dpto. Física Aplicada I Universidad de Sevilla Santiago Hurtado*, Manuel García-León*, Rafael García-Tenorio**

2. 19th July 2002, Salamanca 2 Detector geometry D L R r d Ge tftf thth REGe (Reverse Electrode Germanium) DIMENSIONNOMINAL Crystal radius R27.0 mm Crystal lenght L55.0 mm Window distance 5.0 mm Hole radius5.0 mm Hole depth41.0 mm Thickness hole dead layer 0.5 mm Thickness front dead layer 0.3  m Be window

3. 19th July 2002, Salamanca 3 Experimental setup 15 cm Point sourceMarinelli beaker Radionuclides: 210 Pb, 241 Am, 137 Cs, 40 K, 133 Ba, 152 Eu

4. 19th July 2002, Salamanca 4 REGePhysicsList Cut values , e - and e + LowEnergyPhysics Simulation Class diagram REGe REGeVisManager RegisterGraphicsSystem ->VRML1FILE REGePrimaryGenerator particleGun REGeDetectorConstruction G4Tubs,G4Material,... ->REGe geometry setup REGeCristalHit Hit-> Pos,Edep,weight REGeCristalSD HitsCollection REGeRunAction Histogramfilename REGeEventAction HitsCollection-> Histogramfilename GSPM GenerateBiasFlux ROOT-C++

5. 19th July 2002, Salamanca 5 Variance Reduction technique Zone I Zone II Zone III Zone IV Zone V (x,y,z) Zone II algorithm r R H  min  max Ge

6. 19th July 2002, Salamanca 6 Computing time reduction

7. 19th July 2002, Salamanca 7 ROOT-C++ Analysis Histogram FWHM exp Area calculation  MC

8. 19th July 2002, Salamanca 8 Point results

9. 19th July 2002, Salamanca 9 Marinelli results

10. 19th July 2002, Salamanca 10 Optimized geometry & Efficiency transfer R D L r d Getftf thth D, R -> 240 Am, 210 Pb, 133 Ba (POINT) L -> 240 Am, 210 Pb (MARINELLI) d, r, t h -> 137 Cs, 40 K (POINT- MARINELLI) D+2 mm, R-0.75 mm, L-3 mm, D-3 mm, r+2 mm

11. 19th July 2002, Salamanca 11 Conclusions GEANT4 provides a good agreement: exp. & MC data GEANT4 is useful to setup complicated experimental geometries Versatility of GEANT4 (C++) improves lab experiments (coincidence- summing, background simulation,...)