Electron-track Compton imaging using high-resolution charge-coupled devices

For the past decade, Compton imaging systems have been developed based on position-sensitive semiconductor detectors for use in Homeland Security and Nuclear Safeguards applications. The imaging of gamma-rays enables the localization of radioactive sources, an increase in detection sensitivity by distinguishing between signal and background, and to correlate the location of the source with other contextual information, providing additional means to increase the detection sensitivity. Conventional Compton imaging requires the knowledge of the positions and energies of multiple interactions resulting from a single incident gamma-ray. Our approach for the efficient measurement of Compton electron tracks is to use fully depleted, 650 micron thick, silicon-based charge-coupled devices (CCD) developed at Lawrence Berkeley National Laboratory (LBNL) that are characterized by a lateral spatial resolution of about 10.5 μm. In this paper, we will focus on benchmarked models to determine the gain in sensitivity of electron-tracking based over conventional Compton imaging.