X-ray source downscaling enabled by combining microfabricated electrodes with carbon nanotube cold electron emitters

Abstract

This work reports on the development and the experimental proof of a novel concept of miniaturized X-ray source. This concept is based on microsystems technology and carbon nanotube electron field emitters. Thereby, unseen features such as fast switching and reduced imaging time will be enabled in future applications, such as, for instance, static computed tomography. In this work we describe the fabrication, assembly, and testing of micro-fabricated electrodes and carbon nanotube cold cathodes, based on a new design concept, to be packaged in a miniaturized X-ray source. The source design concept was experimentally validated. X-rays were generated with a total current of up to 4μA extracted from the cathode and an acceleration voltage of 3.1kV. The total current collected on the anode was 0.2–0.4μA which thus corresponds to a collection efficiency on the anode of approx. 10%. The components were assembled and operated in a high vacuum chamber at<10−6mbar. The achieved results from both, the electron and the X-ray emission experiments will be discussed in detail. Furthermore, we comment on the individual components’ limitations as well as on the next steps to be taken in order to optimize the characteristics and performance of the final X-ray source.