A novel geometric design of annular absorber to improve detection efficiency of the Compton camera

The Compton camera is widely used in various applications．A novel high-sensitivity Compton camera with an annular absorber was proposed here and its effectiveness was demonstrated via Geant4 simulation．The detection efficiency and angular resolution of this novel Compton camera were estimated and compared with a traditional Compton camera with two planar detectors．The scatterer of the two Compton cameras were identical and consisted of 8×8 Ce:Gd₃(Al, Ga)₅O₁₂(GAGG) scintillator detector, each measuring 10 mm×10 mm×5 mm．The absorber of traditional camera contained 8×8 GAGG scintillator detector, each measuring 10 mm×10 mm×10 mm．The absorber of this novel camera contained 64 GAGG crystals (measuring 10 mm×10 mm×10 mm each), which were arranged in an annular shape with an inner radius of 51.5 mm and an outer radius of 73.9 mm．Simulation results show that with comparable or even better angular resolution, the novel Compton camera significantly enhanced effective detection efficiency．Data demonstrated that when distance between the scatterer and the absorber is larger than 114 mm, enhancement of detection efficiency is over 1-fold．