Addressable flat-panel x-ray sources for medical, security and industrial applications

Traditional tube-based x-ray sources are widely employed in medical imaging, security screening, and industrial inspection. The cone-beam produced by these tubes is simple to apply, but often demands a long stand-off distance to the object of interest. When combined with the bulk of tubes and their attendant power supplies and cooling systems, the footprint requirement of traditional sources often impedes their use, especially in mobile situations. Here we present an approach to a distributed, flat-panel x-ray source, which eliminates the aforementioned bulk, weight and need for standoff. This source uses spontaneous polarization in pyroelectric crystals to generate high fields and field enhanced emission from micropatterned tips to create a large array of electron beamlets. When combined with a transmission Bremsstrahlung target, a mechanism for raster control of the emitters, and a collimator, this source offers a new and cost effective way to perform stationary and portable imaging. The working principles and performance characteristics of this source are presented. The demands placed on the imaging detector and image processing are also described. Finally, prospects for new promising applications (such as mammography) are mentioned.