Application of Bi Absorption Gratings in Grating-Based X-ray Phase Contrast Imaging

Abstract

Among X-ray phase-contrast techniques, grating-based X-ray differential phase contrast (DPC) imaging using conventional X-ray tube sources is the most prominent one for widespread applications in the case of acquisition of high-quality absorption gratings in mass production. In this letter, we report on a new type of absorption grating made from Bi and manufactured by a micro-casting process. We tested Bi absorption gratings with our X-ray DPC imaging system and obtained high-quality phase-contrast images. Our efforts towards the practical application of X-ray DPC imaging are briefly outlined.

Low Cost and High Efficiency Method for X-ray Phase Contrast Imaging

“…栅通常采用 LIGA 技术在硅基光栅中电镀金的方法制作 [25] ， 这种方法依赖于同步辐射源， 并使用贵金属金作 [26][27] green and red, respectively. The horizontal axis represents X-ray photon energies, and the ordinate axis represents the transmissivity of materials to X-rays Fig.3 Principle of structured scintillator with the function of analyzer grating…”

“…的结构化转换屏 [26][27][28] ， 如图 4 所示。 图 4 系统中所采用光栅器件。 (a) 铋材料源光栅; (b) 相位光栅; (c) 具有分析光栅功能的结构化转换屏 Fig.4 Grating components in the system. (a) Bi-source grating; (b) phase grating; (c) structured scintillator with the function of analyzer grating 材 料 源 光 栅 器 件 ， 可 以 大 大 降 低 源 光 栅 器 件 成 本 ； 采 用 具 有 分 析 光 栅 功 能 的 结 构 化 转 换 屏 代 替 金 材 料 分 析 光 栅 器 件 ， 它 不 仅 大 大 降 低 分 析 光 栅 的 制 作 成 本 ， 而 且 能 够 克 服 高 能 X 射 线 的 限 制 。 采 用 高 温 真 空 微 填 充 技术制备铋材料源光栅可以在普通实验室实现， 但仍然存在填充不均匀以及光栅局部变形的问题。光辅助 电化学刻蚀方法可以制备高深宽比的(100 以上)结构光栅， 但深宽比的增大， 会导致光栅侧向腐蚀问题。随 着 工 艺 技 术 的 进 一 步 改 良 ， 通 过 光 栅 表 面 结 构 改 性 以 及 优 化 光 栅 结 构 设 计 等 方 法 ， 可 以 使 这 些 问 题 得 到 有 效解决。该方法的发展对于实现低成本和高灵敏度的 X 射线光栅微分相衬成像具有重要的实际应用价值。…”

Fabrication of X-ray Gratings for Interferometric Imaging by Conformal Seedless Gold Electroplating

“…Availability of standard lithographic techniques and well-established technologies for silicon microfabrication are additional advantages of this approach, which opens up the route for a cost-efficient production in larger wafer sizes and higher volumes. Several Si-based technologies for the fabrication of metallic X-ray gratings were recently reported: conformal electroplating with partial (also known as spatial frequency doubling technique) [ 12 ] or complete [ 12 , 13 , 14 ] filling; seedless electroplating through a mask [ 15 , 16 ]; metal casting of Bi [ 17 ], as well as of Au [ 18 ] and Pb alloys [ 19 ]; atomic layer deposition (ALD) of Ir [ 20 ]; bottom-up Au electroplating on a metal seed layer [ 21 , 22 , 23 , 24 , 25 ]. Each of the above techniques has its own strengths and weaknesses.…”

Backscattering X-ray imaging using Fresnel zone aperture

“…This wide line width is a significant advantage in the fabrication process to extend the method to high-energy X-rays because the shield part needs to be thickened to block hard X-rays. [36][37][38] To estimate the point spread function, we conducted an experiment simulating a point light source, in which the FZA was placed 66 cm from the X-ray source of a rotating anode X-ray generator (RIGAKU, Ultara18X, Cu target). The effective source sizes are approximately 1 and 4 mm along horizontal and vertical directions, respectively.…”