柔性三维CT高时/空分辨率场发射X射线源阵列制造研究

Three-dimensional CT uses the penetration performance of X-ray to imaging, which applied in bio-medical, security and nondestructive detection. However, traditional research irradiators such as the cesium irradiator and x-ray irradiators lack many of the capabilities found in today’s clinical practice, such as spatial resolution and temporal resolution. This project intends to study a high spatial/temporal resolution field emission X-ray source arrays and the flexible large-area manufacturing process. Lateral zinc oxide nanowires field emission cathode replaced the traditional hot cathode, which reducing power consumption and making X-ray device miniaturization and portability. Using the advantages of the small velocity scattered of field emission electron beam, that the focusing system can be simplified and the manufacturing cost is reduced. Cold cathode array used as the electron emission source, which get planar X-ray images by time series scan. The scanting structure is simple, scanning speed is faster, and the tomographic image is more. The reconstruction three-dimensional image is clearer, and achieve to detection the dynamic organ rapidly. Therefore, this project intended to study the device structure, manufacturing processes, and the functional characteristics. It intended to study the structure of the array of flexible substrate plane nano sharp cone field emission electron source, Electronic flight characteristics of high spatial/temporal resolution field emission X-ray source, and thermal mechanisms of the flexible field emission X-ray source arrays. Developing a low-cost, flexible, lage-area, high spatial/temporal resolution field emission X-ray source array and the new manufacturing processes.

三维CT利用X射线的穿透作用进行三维成像，广泛应用于医疗、安检、无损探测等。针对当前三维CT设备的X射线源结构及机械扫描方式，导致探测与成像速率低、成像模糊等问题，本项目拟研究一种柔性三维CT高时/空分辨率场发射X射线源阵列结构及制造工艺。以ZnO纳米线横向场发射阴极取代传统热阴极，实现X射线源系统的低功耗、小型化、便携化；利用场发射电子束初速零散较小的优点，简化聚焦系统、降低制造成本；采用冷阴极阵列电子发射源，实现时间序列扫描的平面X射线影像，简化扫描结构、提高扫描速度、增加断层图像数量、提升三维重构图像分辨率，同时实现动态生物器官的实时快速检测。为此，从器件结构、制造工艺方法等方面，拟研究阵列化面内纳米尖锥场发射电子源结构、高时/空分辨率场发射X射线源电子飞行控制、柔性场发射X射线源阵列的导热机制等，发展低成本、柔性大面积、高时/空分辨率场发射X射线源阵列制造工艺。

三维CT利用X射线的穿透作用进行三维成像，广泛应用于医疗、安检、无损探测等。针对当前三维CT设备的X射线源结构及机械扫描方式，导致探测与成像速率低、成像模糊等问题，项目研究一种柔性三维CT高时/空分辨率场发射X射线源阵列结构及制造工艺。以ZnO纳米线横向场发射阴极取代传统热阴极，实现X射线源系统的低功耗、小型化、便携化；利用场发射电子束初速零散较小的优点，简化聚焦系统、降低制造成本；采用冷阴极阵列电子发射源，实现时间序列扫描的平面X射线影像，简化扫描结构、提高扫描速度、增加断层图像数量、提升三维重构图像分辨率，同时实现动态生物器官的实时快速检测。从器件结构、制造工艺方法等方面，研究阵列化面内纳米尖锥场发射电子源结构、高时/空分辨率场发射X射线源电子飞行控制、柔性场发射X射线源阵列的导热机制等，发展低成本、柔性大面积、高时/空分辨率场发射X射线源阵列制造工艺。项目实现以悬臂梁式ZnO纳米线为场发射体，以平面多栅极为电子运行轨迹控制的阵列化、柔性化场发射X射线源。阵列化达到5×5个场发射X射线源，柔性化达到厘米级最大弯曲半径，面积达到4英寸，时间分辨率为电信号扫描速率，空间分辨率达到10um；构建了场发射多栅极结构的几何优化参数和理论模型。具有包括栅极数量、栅极间距、栅极几何图形等优化值范围，以及各栅极电压、阳极电压等参数与场发射电子聚焦、电子飞行速度的关系等；提出基于绝缘微墙支撑的平面多栅极电子束运行轨迹调控结构；提出了完整的三维CT场发射X射线源的阵列化、柔性化制造工艺。包括悬臂梁式场发射ZnO纳米线的侧壁可控生长工艺，绝缘微墙支撑的多栅极电子调控电极的多层图形套印对准工艺，和铜靶表面石墨烯薄膜的可控生长工艺。发展了一种低成本、柔性化、高时/空分辨率场发射X射线源阵列及其制造工艺。