Presentaci

1
Efficiency calibration of a Germanium gamma-ray
detector using GEANT4
Santiago Hurtado, Manuel García-León, Rafael
García-Tenorio
Dpto. Física Atómica, Molecular y Nuclear
Dpto. Física Aplicada I Universidad de Sevilla
2
Detector geometry
REGe (Reverse Electrode Germanium)
Be window
D
DIMENSION NOMINAL
Crystal radius R 27.0 mm
Crystal lenght L 55.0 mm
Window distance 5.0 mm
Hole radius 5.0 mm
Hole depth 41.0 mm
Thickness hole dead layer 0.5 mm
Thickness front dead layer 0.3 ?m
Ge
tf
L
d
th
r
R
3
Experimental setup
Radionuclides 210Pb, 241Am, 137Cs, 40K, 133Ba,
152Eu
15 cm
Point source
Marinelli beaker
4
Simulation Class diagram
REGe
5
Variance Reduction technique
Zone II algorithm
r
(x,y,z)
R
?min
Zone II
Zone I
?max
Ge
H
Zone III
Zone IV
Zone V
6
Computing time reduction
7
ROOT-C Analysis
Histogram
FWHMexp
?MC
Area calculation
8
Point results
9
Marinelli results
10
Optimized geometry Efficiency transfer
D, R -gt 240Am , 210Pb , 133Ba (POINT) L -gt
240Am , 210Pb (MARINELLI) d, r, th -gt 137Cs ,
40K (POINT-MARINELLI)
D2 mm , R-0.75 mm , L-3 mm , D-3 mm , r2 mm
R
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, ...)