Monte Carlo investigation of a high-efficiency, two-plane Compton camera for long-range localization of radioactive materials

• Published in: Progress in nuclear energy (New series) Vol. 81; no. C; pp. 127 - 133
• Main Authors: Poitrasson-Rivière, Alexis, Maestas, Ben A., Hamel, Michael C., Clarke, Shaun D., Flaska, Marek, Pozzi, Sara A., Pausch, Guntram, Herbach, Claus-Michael, Gueorguiev, Andrey, Ohmes, Martin F., Stein, Juergen
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.05.2015; Elsevier
• Subjects: Cameras; Compton imaging; Computer simulation; Detectors; Gamma rays; Inorganic scintillators; INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; Monte Carlo methods; Monte Carlo simulations; NUCLEAR FUEL CYCLE AND FUEL MATERIALS; Organic scintillators; Planes; Position (location); Radioactive materials; Gamma rays; Inorganic scintillators; Compton imaging; Monte Carlo simulations; Organic scintillators
• ISSN: 0149-1970
• DOI: 10.1016/j.pnucene.2015.01.009

Compton cameras have become an instrument of interest for long-range localization of radioactive materials in nuclear-nonproliferation applications. In this work, a specialized simulation tool was developed for the optimization of a Compton camera through realistic Monte Carlo simulations. This tool can be used for Compton cameras with different geometries. The MCNPX-PoliMi code was used to simulate Compton scatters and photoelectric absorptions in the camera's detectors. The imaging capability is derived from the physics of Compton scattering and the full-energy information obtained in photoelectric absorptions. The simulated system is a 1 × 1 m2 Compton camera consisting of two planar arrays of photon detectors. Several scintillators were evaluated: LaBr3, CaF2, and NaI(Tl) (all inorganic scintillators), and C9H10 (plastic organic scintillator). The investigation was carried out with a 137Cs source. A minimum detectable activity (MDA) was defined and used to assess the performance of cameras based on different detectors. The simulation results show that C9H10 is a reliable, low-cost, scatter-plane material, increasing the MDA by ∼0.2 mCi when compared to a CaF2 scatter plane. On the other hand, the intrinsic background of LaBr3 undermines its above-average energy resolution as the MDA increased by ∼0.5 mCi when compared to a NaI(Tl) absorption plane. •We model large-scale Compton cameras for long-distance imaging, using MCNPX-PoliMi.•We investigate 4 different scintillators: C9H10, CaF2, NaI, and LaBr3.•We assess the performance of the different cameras using the backprojection images.•The CaF2/NaI is the camera with the best performance.•The C9H10/NaI camera shows an acceptable performance drop for a lower price.