Monte Carlo investigation of a high-efficiency, two-plane Compton camera for long-range localization of radioactive materials. (May 2015)

• Record Type: Journal Article
• 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
• Is Part Of: Progress in nuclear energy. Volume 81(2015:May)
• Page Start: 127
• Page End: 133
• Publication Date: 2015-05
• Subjects: Compton imaging -- Gamma rays -- Monte Carlo simulations -- Organic scintillators -- Inorganic scintillators; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 333.7924
• DOI: 10.1016/j.pnucene.2015.01.009
• Languages: English
• ISSNs: 0149-1970

Abstract

Abstract: 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 m 2 Compton camera consisting of two planar arrays of photon detectors. Several scintillators were evaluated: LaBr3, CaF2, and NaI(Tl) (all inorganic scintillators), and C9 H10 (plastic organic scintillator). The investigation was carried out with a 137 Cs 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 C9 H10 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. Highlights: We model large-scale Compton cameras for long-distance imaging, using MCNPX-PoliMi. We investigate 4 different scintillators: C9 H10, 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 C9 H10 /NaI camera shows an acceptable performance drop for a lower price.