Fabrication of Gratings for an X-ray Talbot Interferometer

Abstract

X-ray based imaging measurement has found applications in fields such as medical diagnosis and nondestructive inspection, having become one of essential technologies. However, its low sensitivity to biologically soft tissues limits scope of applications. Several methods have been developed for X-ray phase imaging. We proposed a method using an X-ray Talbot interferometer. It offers advantages; it is a very simple setup using two gratings; it has a potential of phase imaging with a compact laboratory X-ray source, but the fabrication of an amplitude X-ray grating is a difficult, because the structure of grating must have high aspect ratio. We used deep X-ray lithography and electroforming of Au in fabricating gratings. The period and height of the grating were 5.3mum and 31mum. We evaluated the gratings, successfully achieved a high visibility of 71%. With the gratings that had a period of 8 mum and a height of 29 mum, we conducted X-ray phase tomography of rabbit liver and a mouse tail. As a result, we successfully observed soft tissues and high-density tissues. The gratings, therefore, had sufficient performance to conduct phase tomography