Focal Spot Size Enhancement by Offset control of Triode e-beam Module for High Resolution X-ray Imaging

Demands on high quality x-ray imaging techniques are required for early detection of abnormal tissues and quality control of mass production in the field of medical and industrial applications.Moreover, smaller focal spot size (FSS) of x-ray sources have been developed for many decades but still their structure and operational scheme are complicated. To optimize electron beam trajectory, at least two types of focusing electrodes are needed. We demonstrate under 0.5 mm FSS of cold cathode x-ray source triode type e-beam module with vertically aligned carbon nanotubes (VA-CNTs) without any additional focusing electrodes. In addition, gate hole offset effects were investigated to FSS.The authors anticipate that our simple but sophisticated gate structure will be beneficial for high quality x-ray imaging and cost effective in terms of massive production of cold cathode x-ray generators.