Design and fabrication of a new tungsten-diamond transmission target for micro-computed tomography

The Micro-CT uses X-ray to detect the internal structure of a sample on micro&nano scale without destroying it, the main challenges in manufacturing a high power Micro-CT is a target with fast heat dissipation to produce high power intensity of X-ray. In this manuscript, we introduce our progress in manufacturing a target that can withstand higher power of electron beam than previous. Firstly, Monte-Carlo simulation (Genat4) is constructed to determine the optimal thickness of the tungsten film, which optimize the intensity of X-ray. In addition, we examine heat dissipation of tungsten and aluminum by finite element method and find that diamond is the most suitable material for substrate, because it results in the lowest temperature near the impact point according to our simulation. Thirdly, the magnetron sputtering method is used to fabricate a tungsten film on the diamond substrate. We highlight that the Micro-CT based on this target achieve a high resolution of 3 mu m, and the power of electron beam is 10 watts. Based on these improvements, the experiments show that our tungsten-diamond target provides much better perfounance with quicker heat dissipation rate (i.e. with lower temperature near the impact point) and the stronger power of X-ray than previous works.