Novel Composite X-ray Target Material

In X-ray sources, most X-ray photons are produced via bremsstrahlung interaction, in which nearly 99% electrons’ kinetic energy is converted to heat. Thus heat management is critically important in X-ray tube design. With large amount of heat deposited on a small spot size, the maximum focal spot power density of X-ray tubes is about 0.5-1 kW/mm2, limited by the thermal conductivity of the target material. Focal spot power density limits the tube power and focal spot size, especially for a multi-pixel thermionic X-ray (MPTEX) source, in which a fixed anode is used.

We are developing a novel composite X-target material using annealed pyrolytic graphite (AGP), which has extremely high thermal conductivity in its a-b plane. The new X-ray target is expected to achieve improved focal spot power density due to the exceptionally high thermal conductivity of APG.

Thermal conductivities of different materials.

AGP-W composite target.

Collaborators

We are developing the W-APG target with collaborators from the Washington University Department of Physics (Prof. Erik Henriksen) and the Washington University Institute of Materials Science & Engineering (IMSE).