Field emission gun for X-ray tubes

The attempt to replace hot cathode with field emission cathode in a commercial X-ray tube have been made. We are continuing investigation of emission properties of the carbon fibers. Cathodes for X-ray tube were made from bundle of carbon fibers. The prototype provides 0.1 mA with focus spot about ∅2 mm under continued 40 kV mode. Each tube contain cathode made of single fibers bundle. The matrix cathode to increase total tube current up to 10 mA/cm2 for macro cathode structure is also considered.