Carbon Nanotube Field Emission Micro-focus X-ray Tube

DESCRIPTION (provided by applicant): This is a revised Phase II application based on 2006 application and reviewers' comments. In this version, we made significant modifications, including: change the two rings cathode design to three rings structure, addi ng the synchronization gating control effort, and details of the processing and manufacturing of the carbon nanotube (CNT) cathodes and x-ray tubes. During this period, we achieved dramatic progress on the CNT x-ray technique, which makes us confident the success of this development. 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 anim al 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 emiss ion source as the cathode to overcome disadvantages of the hot electron sources in the present x-ray tubes. After Phase II, we expect to be able to develop the CNT field emision micro-focus x-ray tube with the following features: spatial resolution (effect ive focal spot size): adjustable with 10 5m, 30 5m, and 100 5m three levels; temporal resolution: adjustable, from 0.1 to 100 ms; X-ray tube current: adjustable, up to 2 mA peak current at 100 5m resolution; anode voltage: 40-60 KVp; synchronization gating control; and lifetime: up to 3000 hours. The primary application of the proposed x-ray source is for small animal imaging related medical research and diagonosis. The major research design and methods to achieve the proposed development goals include: 1) Construction of the micro-focus x-ray tube with resolution of 30 5m based on Phase I study; 2) Development of the compact CNT field emission 10 5m micro-focus x-ray source meeting key Phase II targets; 3) Design and assembly of the compact electronic c ontrol system for the x-ray source of Aim 2; 4) Construction of a sealed and portable micro-focus x-ray tube with the specifications of Aim 2; and 5) Demonstration of the high resolution dynamic micro-CT imaging.