一种旋转调制器成像技术研究  

Study on rotating modulator imaging technique

作　　者：魏星[1] 王锋[1] 肖无云[1] 艾宪芸[1] 张斌[1] 张磊[1] 马新华[1] 

机构地区：[1]防化研究院国民核生化灾害防护国家重点实验室,北京102205

出　　处：《核技术》2014年第2期37-44,共8页Nuclear Techniques

摘　　要：γ射线成像技术在核安全领域正逐渐受到人们重视。为了在提高成像系统灵敏度的同时尽可能降低系统复杂度和成本,一种采用非位置灵敏探测器的旋转调制器成像技术被首次引入到核监测技术领域。为研究该技术的理论基础、调制传递函数、图像重建方法等,开展了仿真研究工作。结果表明,同等探测器面积下,旋转调制器成像系统的灵敏度约为编码孔成像系统的62%,但旋转调制器成像系统的探测器数量扩容性很强,能在系统复杂度增加不多的情况下提高探测器总面积,从而极大提高系统灵敏度;通过迭代重建方法能得到超过系统几何角度分辨率的目标图像,在像距80cm,探测器直径3.8cm时,重建图像的角度分辨率约为0.8°。最后根据仿真结果提出了适于小型车辆或机器人等移动平台的原理性装置的设计方案。Background： Nuclear security and safety is becoming one of the most concerned topics around the world after Fukushima nuclear accident. Recent reports of IAEAshow that the potential risks exist internationally and domestically. A good solution of promoting nuclear security and safety is to develop advanced nuclear radiation monitoring technologies including y-ray imaging. Purpose： In order to improve the sensitivity of a y-ray imaging system with little increase of system complexity and cost, rotating modulator （RM） imaging technique using non-position-sensitive detectors was first introduced in nuclear monitoring studies. Methods： Modulation pattern of RM system was deduced mathematically and its profile was calculated by a dedicated program written in Matlab. The system sensitivity was analyzed based on the profile. Detector outputs were produced by Monte Carlo simulation. The Noise-Compensating Algebraic Reconstruction （NCAR） algorithm was applied to the image reconstruct from simulated outputs. Results： ARM imaging system has a relative sensitivity of 62% compared with a coded aperture system when detector areas of the two systems are equal. On condition that the detector diameter is 3.8 cm and image distance is 80 cm, an angular resolution of 0.8° is achieved. Conclusion： Based on the simulating results, a RM system design suitable for vehicle and robotic platform is proposed.

关 键 词：y射线成像 旋转调制器 系统灵敏度 图像重建 迭代法 

分 类 号：TL812[核科学技术—核技术及应用]