ARI-MA: Electron Tracking for Advanced Gamma-Ray Imaging Applications in Homeland Security

该项目的目标是增强最近演示的基于电子跟踪的康普顿伽马辐射成像概念。这一概念有望提高核安全的检测、定位和表征能力，也可用于生物医学成像或天体物理学等其他领域。我们的方法是基于高分辨率的硅基电荷耦合器件（CCD）传感器，它提供足够的分辨率来确定通过康普顿散射过程散射的电子的初始方向。这使得入射伽马射线的重建事件逐个事件的基础上，而不使用灵敏度限制准直器。硅和10微米像素尺寸的结合，既能提供足够的位置分辨率来确定入射方向，又能提高诱导康普顿散射过程的效率。本项目旨在从硬件和软件两方面系统地评估和改进当前的实施情况。跟踪电子和执行图像重建的初步算法已经开发出来，可以通过考虑可以观察到的特征的更多细节以及通过将电子和伽马射线信息相关联来改进。CCD方法的慢帧率目前限制了事件到事件的重建。我们将实现CCD的条带读出，以实现电子轨迹和相关伽马射线的事件到事件重建，并实时演示基于电子跟踪的康普顿成像。该项目的目标是展示辐射探测方面的一种新概念，从而可能大大提高核材料的探测、定位和表征能力。最近和正在开发的高分辨率Si传感器可用于测量相互作用过程的细节，可用于获得更多信息以重建伽马辐射。可以设想在国土安全、核不扩散和国际保障、生物医学成像以及天体物理学和核物理学方面的应用。该项目将为青年科学家提供优秀的培训。

The goal of this project is to enhance the recently demonstrated concept of electron-tracking based Compton imaging of gamma radiation. This concept promises to increase the detection, localization, and characterization capabilities for nuclear security but also in other areas such as biomedical imaging or astrophysics. Our approach is based on high-resolution Si-based charge-coupled device (CCD) sensors which provides sufficient resolution to determine the initial direction of the electron that was scattered by means of the Compton scattering process. This enables the reconstruction of incident gamma rays on event-by-event basis without using a sensitivity-limiting collimator. The combination of Si and a pixel size of 10 um enables both sufficient position resolution to determine the incident direction and efficiency to induce the Compton scattering process. This project specifically aims at systematically evaluate and enhance the current implementation in terms of hardware and software. Preliminary algorithms to track the electron and to perform image reconstruction have been developed which can be improved by taking into account more details of the features that can be observed and by correlating the electron and gamma-ray information. The slow frame rate of the CCD approach is currently limiting the event-to-event reconstruction. We will implement the strip readout of the CCD to enable the event-to-event reconstruction of the electron track and the associated gamma ray and demonstrate electron-tracking-based Compton imaging in real time.The goal of this project is the demonstration of a new concept in radiation detection that enables potentially significant increased capabilities in the detection, localization, and characterization of nuclear materials. Recent and ongoing developments of very-high-resolution Si sensors can be used to measure details of interaction processes that can be used to gain more information to reconstruct gamma radiation. Applications can be envisioned in homeland security, nuclear non-proliferation and international safeguards, biomedical imaging as well as astrophysics and nuclear physics. The project will provide the excellent training of young scientists.