Field emission from CNT bundles for application in biomedical equipment

For devices such as next generation x-ray radiography equipment, a small x-ray spot along with fast switching is desired to obtain high resolution images. Since the intensity of the x-ray radiation is proportional to the emission current hitting the anode, a high current combined with a small focal spot of electron is desired for spatial resolution. To minimize the motion-induced blurring of images of moving organs such as heart, high temporal resolution is desired which in turns depends on the switching time of the x-ray sources. This combination of spatial and temporal resolution renders the conventional hot cathode less suitable due to its non-Gaussian beam and slow response time, respectively. Field emitters, especially carbon nanotube-based emitters, seem to meet the above requirements and have the potential to be ideal electron source for next generation x-ray tubes.