A microfocus X-ray tube based on a microstructured X-ray target

We present a novel concept to develop a microfocus X-ray tube based on a microstructured X-ray target that is irradiated with a nonfocused electron beam. X-ray emissions from the microstructured targets with various morphologies were studied using Monte-Carlo simulation code MCNP5. The calculations revealed that the microstructured targets are quite capable of minimizing the effective X-ray spot size compared with those of conventional transmission-type X-ray targets. Based on the simulation results of X-ray brightness, optimum geometric parameters were derived for the microstructured targets with different morphologies. Moreover, the stability of the microstructured target against heat loads delivered by an electron beam was also investigated under both the continuous and pulsed operation modes. From the analysis, the limitations of the maximum allowable electron beam currents for the stable operation of the X-ray targets are presented. The combination of the microstructured targets and nonfocused electron beam allows the miniaturization of a microfocus X-ray tube by eliminating the needs for massive and complex focusing devices. (C) 2009 Elsevier B.V. All rights reserved.