Fabrication of x-ray absorption gratings via deep x-ray lithography using a conventional x-ray tube

Background: X-ray grating interferometry is an emerging imaging technique that strongly relies on fine grating structures. A common method to fabricate compatible gratings is deep x-ray lithography (DXRL). Aim: To develop a method to fabricate grating structures by DXRL, which does not require a synchrotron source. Approach: The synchrotron source is replaced by a conventional x-ray tube. The fabrication process is adapted for the divergent beam by cylindrically bending mask and substrate. Results: A 10-mu m period absorption grating with 80-mu m-thick gold lamellae is successfully fabricated from an intermediate 110-mu m high structured resist. This grating is characterized and implemented in a preclinical Talbot-Lau interferometer designed for medical thorax imaging. Conclusion: This approach can overcome the strong dependence on synchrotron facilities for the fabrication of gratings for x-ray grating interferometry. As x-ray tubes are more widely available, this is a cost-efficient and scalable alternative suitable for industrial production. (C) 2021 Society of Photo-Optical Instrumentation Engineers (SPIE)