Fabrication of X-ray absorption grating using an ultracentrifuge machine

Abstract

We propose a novel approach to fabricate hard-X-ray optics using an ultracentrifuge machine. As a demonstration, we fabricated an X-ray absorption grating made of gold with a pitch of 30 μm and an effective depth of 44 μm in 67 μm depth grooves [a filling rate of 65%, as same as the filling rate of random packing for equal-sized spheres in a jammed state (64%)]. Our approach is cost-efficient and has a high production-rate and material-selectivity, and will be widely used for fabricating optics not only for X-rays but also neutrons in the near future.

Performance comparison of x-ray absorption gratings fabricated by free deposition and centrifugal filling methods

“…Still, filling narrow trenches or pores of the feedstock is challenging. Recently, more filling methods were proposed to fabricate x-ray absorption gratings, such as free deposition using tungsten nanoparticles (TNs) and centrifugal filling using tungsten and gold particles [15,18,19]. In the free deposition method, TNs gradually fall and deposit into the pre-prepared grating trenches only under the action of gravity.…”

“…Additionally, the density of nanoparticles depends on their self-arrangement, which is generally affected by many factors. The centrifugal filling method has been used to arrange gold microparticles in the gratings with a period of 30 µm [18], and bimodal tungsten particle mixture into trenches of gratings having a period of 45 µm with the action of centrifugal force [19]. The centrifugal filling has been proven to be highly efficient in arranging particles densely.…”

“…Until now, there has been no performance comparison of absorption gratings prepared by free deposition and centrifugal filling. In addition, most previous work on particle filling focused on the fabrication of the longperiod absorption gratings having periods up to several tens of micrometers [15,18,19]. The feasibility of centrifugal filling as an efficient method for short-period absorption gratings is yet to verify.…”

Fabrication of X-ray absorption grating by thermal composite method

“…In 2013, Lei proposed a micro-casting method. [33][34][35][36][37][38] In 2017, Romano proposed a metallic glass imprinting method. 36,39,40) In the above micro-casting method and hot embossing technology, the grating is easily affected by temperature, which causes the grating to be deformed and damaged.…”

An 8-inch absorption grating used in cascaded Talbot-Lau interferometers for X-ray phase-contrast imaging

“…Recently, absorption gratings fabricated with tungsten and gold particles were reported, and they showed good performances in X-ray absorption. 22,23) Up to now, fabrication of absorption gratings (no less than 8 inches diameter) with low-cost has not been reported. In this letter, we report a low-cost 8 inch absorption grating fabricated by filling tungsten nanoparticles into grating structures.…”