Development of microfocus x-ray source based on CNT emitter for intraoperative specimen radiographic system

High-Performance Cold Cathode X-ray Tubes Using a Carbon Nanotube Field Electron Emitter

“…Four kinds of electron emitters such as the CNT emitter using a free-standing CNT film (CNT film emitter), the tungsten filament emitter, the Si tip emitter, and the CNT paste emitter were selected. − ,,,− From comparison results, it is well understood that our cold cathode X-ray tube shows a much high tube current density at a small focal spot size. By the way, some X-ray tubes indicate a smaller focal spot size than our cold cathode X-ray tube but even though they show a relatively lower tube current. ,, Such kinds of X-ray tubes can be used for limited X-ray application systems like high-resolution X-ray microscopy or nondestructive analysis or medical mammography due to a small focal spot size. However, the cold cathode X-ray tube should guarantee a high tube current density and a small focal spot size for diverse applications to medical X-ray diagnosis systems like X-ray radiography or X-ray CT.…”

“…By the way, some X-ray tubes indicate a smaller focal spot size than our cold cathode X-ray tube but even though they show a relatively lower tube current. 4,18,24 Such kinds of X-ray tubes can be used for limited X-ray application systems like high-resolution X-ray microscopy or nondestructive analysis or medical mammography due to a small focal spot size. However, the cold cathode X-ray tube should guarantee a high tube current density and a small focal spot size for diverse applications to medical X-ray diagnosis systems like X-ray radiography or X-ray CT.…”

“…Recently, a cold cathode X-ray tube has much attention due to possibility of several advantages such as a high resolution, fast operation, digital operation, a small focal size, and low power consumption. Diverse approaches to fabricate cold cathode X-ray sources have been studied by adopting field electron emitters using various field emission materials such as semiconductor tips, carbon nanotubes (CNTs), and nanocarbon materials. − More recently, several research groups reported cold cathode X-ray tubes which can promise potential applications for various X-ray systems even though a history of cold cathode X-ray tubes is only a beginning stage. − Furthermore, some companies such as Shang Fang, Micro-X, Nanox, and CAT beamtech presented commercial cold cathode X-ray tubes using CNT paste emitters or as-grown CNT emitters or Si tip emitters and started to supply cold cathode X-ray tubes with various specifications in the market. Nevertheless, the cold cathode X-ray tubes still show a relatively low tube current and a large focal spot size, which indicates lower tube performance compared with conventional thermionic X-ray tubes.…”