Carbon Nanotube Field-Emission Micro-focus X-ray Tube

描述（由申请人提供）：实质性的技术发展激发了人们对成像技术的新兴趣，它们的使用也有了相当大的增长。高分辨率小动物成像系统已成为实验室动物研究的重要新工具。x射线成像广泛应用于诊断放射学、生物医学研究和各种工业应用。为了克服现有x射线管中热电子源的缺点，提出以碳纳米管（CNT）场发射源为阴极，设计和制造一种便携式、低成本的微聚焦x射线管。通过实施所提出的研究（第一阶段和第二阶段），我们希望能够展示具有以下特点的新型紧凑x射线管：高成像分辨率低至30 μ m或更小，30 ~ 100 μ m范围内的电子可控有效焦斑，延长寿命达3000小时的便携式设备，能够以每幅图像1-10毫秒（msec）的速率触发x射线，100-500 μ a的管电流在40-100KVp电压下具有1%的稳定性。提出的x射线源的主要应用是小动物成像。实现发展目标的主要研究设计和方法包括：a)专有碳纳米管材料的合成和加工；b)能够产生1-5 A/cm2场发射电流密度的碳纳米管场发射阴极的制备，c)采用新泰克开发的碳纳米管源技术集成门控电子源，d)评估电子发射特性，包括阈值场，电流稳定性和寿命，e)便携式x射线装置原型的设计和构建，f)简化焦点结构的电子光学计算机模拟。g)通过研究x射线能谱、通量、高压稳定性、空间分辨率/焦斑、毫秒脉冲宽度的脉冲x射线辐射等关键成像特性，对新型x射线管进行评价。

DESCRIPTION (provided by applicant): Substantial technological growth has spurred a new interest in imaging techniques, and their usage has grown considerably. High-resolution small animal imaging systems have emerged as important new tools for laboratory animal research. X-ray imaging is widely used in diagnostic radiology, biomedical research and a wide variety of industrial applications. We propose to design and construct a portable, low cost micro-focus x-ray tube using the carbon nanotube (CNT) field emission source as the cathode to overcome disadvantages of the hot electron sources in the present x-ray tubes. By implementing the proposed research (Phase I and II), we expect to be able to demonstrate new compact x-ray tube with the following features: high imaging resolution down to 30 um or smaller, electronic controllable effective focal spot in 30 ~ 100 um range, portable device with extended lifetime of up to 3000 hours, capability of electronic triggering the x-ray at the rate of 1-10 millisecond (msec) per image, 100-500 uA tube current with 1% stability under 40-100KVp voltage. The primary application of the proposed x-ray source is for small animal imaging. The major research design and methods to achieve the proposed development goals include: a) Synthesis and processing of proprietary carbon nanotube materials; b) Fabrication of CNT based field emission cathode capable of generating 1-5 A/cm2 field emission current density, c) Integration of gated electron source employing the CNT source technique developed at Xintek, d) Evaluation of the electron emission characteristics including threshold field, current stability, and lifetime, e) Design and construction of prototype portable x-ray device, f) Computer simulation to the electron optics designed to simplify the focus structure, g) Evaluation of the new type x-ray tube by studying the key imaging characteristics: x-ray energy spectrum, flux, high voltage stability, spatial resolution/focal spot, pulsed x-ray radiation with millisecond pulse width.