Using a Geant4 Application for Tomographic Emission(GATE) and a DETECT2000 simulation tool, we designed a detector to track the locations at which gamma-rays interacted with the scintillator. After the locations of the gamma ray interactions with the scintillator had better obtained through the GATE program, that information was used in the DETECT2000 simulation tool to generate light. The detector was composed of two layers of scintillators, and the photosensor used a silicon photomultiplier (SiPM). The upper scintillator was wrapped with a specular reflector and the bottom was wrapped with a diffuse reflector. Photoelectric peaks were positioned at different positions when energy spectra obtained by varying the signal size obtained from the photosensor by treating the layers with different reflectors. The layers in which the scintillators and the gamma rays interacted could be distinguished by using a positional analysis of photoelectric peaks. This method can be used to develop detectors to measure the depths of interaction in the future.

Keywords: Gamma detector, Depth-of-interaction, Energy spectrum, GATE, DETECT2000