Abstract: Both of the LaBr3:Ce and NaI(Tl) detectors are inorganic scintillators that due to their high light output rate in comparison with organic scintillators and almost other inorganic scintillators are significant. In this research, experimental data for identical measurement of the sealed button sources with both detectors in the presence and absence of the shield were compared with the simulation data by using MCNP 4C code for the crystals of detectors. The obtained results from the radioactive sealed button sources measurements represented that for low energy gamma rays there are noticeable differences between the experimental and simulation data and that is highly due to non-negligible and effective attenuation of these low energy gamma rays in passing through the window and the shield of detectors included the crystals. The high energy gamma rays simulation data are, however, in agreement with the experimental observations. Also, all the simulation data as well as the experimental measurents showed that the efficiency of the LaBr3:Ce detector is higher than that of the NaI(Tl) detector. The simulation results for the shielded button sources are also in agreement with the experimental data in most ranges of gama energies.
Keywords: Scintillation detectors, Simulation, MCNP 4C, LaBr3:Ce, NaI(Tl)
J. of Nucl Sci. and Tech 71