A Portable Three-Layer Compton Camera for Wide-Energy-Range Gamma-ray Imaging: Design, Simulation and Preliminary...

Area of Science:

• Nuclear physics
• Medical physics
• Materials science

Background:

• Compton camera imaging is limited above 3 MeV due to incomplete photon absorption.
• High-energy gamma-ray imaging is vital for nuclear security, chemical agent detection, and proton therapy verification.

Purpose of the Study:

• To develop a Compton camera capable of imaging gamma rays across a broad energy range (0.3–7 MeV).
• To demonstrate the feasibility of high-energy gamma-ray imaging for specialized applications.

Main Methods:

• A portable three-layer Compton camera prototype was constructed using a silicon photomultiplier array and a Gd3Al2Ga3O12:Ce scintillator array.
• A list-mode maximum likelihood expectation maximization algorithm and a two-interaction event method were employed for image reconstruction.
• Detector simulations were performed using the Geant4 Monte Carlo toolkit.

Main Results:

• The prototype successfully reconstructed images of 133Ba, 137Cs, and 60Co sources, with effective imaging events at approximately 2%.
• Reconstruction of a 0.05 μSv/h 137Cs source distribution was achieved in 10 seconds, with an angular resolution of 15° for two sources.
• Simulated imaging of 6.13 MeV gamma rays demonstrated capability for high incident energies.

Conclusions:

• The developed Compton camera prototype exhibits effective imaging performance across a wide energy range (0.3–7 MeV).
• The technology shows significant potential for various applications requiring MeV gamma-ray imaging.