Time of flight X-ray imaging for security applications

边境安全是当务之急。侦察违禁品、麻醉品、枪支等需要改进技术解决办法，以便在入境点和其他地方更好地识别这些材料。在这个建议中，我们将研究使用后向散射x射线来产生车辆或集装箱中运输的货物内部材料的三维图像。使用脉冲x射线源，后向散射x射线的飞行时间将用一组闪烁探测器来测量，以便获得可用于创建三维图像的数据。在达斯伯里的VELA设施中使用单个探测器进行的初步实验表明，飞行时间与物体的位置和组成之间存在关系。由于探测器阵列的飞行时间只有几纳秒，因此有必要开发一种快速的数字数据采集系统。此数据采集开发及系统在两组实验中的应用是本方案的重点。多达8个闪烁探测器阵列和数据采集系统将在达斯伯里的VELA设施中使用，用于收集数据，随后将进行分析，以显示其产生三维图像的潜力。然后，该系统将在斯托克的Rapiscan设施中使用，那里的脉冲x射线束更像那些可以广泛部署的设备。这些实验将研究改进系统的响应和在第一部分工作中开发的算法。

Border security is a high priority. The detection of contraband, narcotics, firearms etc. requires improved technical solutions to improve the identification of these materials at entry points and elsewhere. In this proposal we will investigate the use of backscattered x-rays to produce a three dimensional image of the materials inside cargo that is being carried in vehicles or containers. Using a pulsed x-ray source the time of flight of the backscattered x-rays will be measured with an array of scintillation detectors in order to obtain data that can be used to create a three dimensional image. Preliminary experiments at the VELA facility at Daresbury using a single detector have shown a relationship between the time of flight and the position and composition of an object. As the time of flight is a few nanoseconds it is necessary to develop a fast digital data acquisition system for the detector array. This data acquisition development and the use of the system in two sets of experiments are the focus of this proposal. The array of up to eight scintillation detectors and the data acquisition system will be used at the VELA facility at Daresbury to collect data that will be later analysed to show its potential for producing three dimensional images. The system will then be used a Rapiscan's facility at Stoke where the pulsed x-ray beam is more like those that could be widely deployed. These experiments will investigate improving the response of the system and the algorithms developed in the first part of the work.