X-ray phase contrast microscopy at 300 nm resolution with laboratory sources

Abstract

We report the performance of an X-ray phase contrast microscope for laboratory sources with 300 nm spatial resolution. The microscope is based on a commercial X-ray microfocus source equipped with a planar X-ray waveguide able to produce a sub-micrometer x-ray beam in one dimension. Phase contrast images of representative samples are reported. The achieved contrast and resolution is discussed for different configurations. The proposed approach could represent a simple, inexpensive, solution for sub-micrometer resolution imaging with small laboratory setups.

Laboratory-based quantitative hard x-ray phase microscopy in one dimension using waveguides

“…The width of the WG was 500 nm and its length was 5 mm. The WG was located 125 cm downstream of the multilayer mirrors, acting as an effective one-dimensional secondary source [7]. A Medipix2 detector with 55 μm pixel size and 500 μm thick silicon chip was used to detect x-rays.…”

“…Reducing the dimension of the x-ray source (or its divergence) is the key to obtain a sufficient degree of coherence [6]. Recently, an experimental setup, able to produce a sub-micrometer x-ray beam for projection microscopy with laboratory sources, was demonstrated using x-ray waveguides in 1D [7] and 2D [8]. The principle of operation of an x-ray waveguide (WG) is total internal reflection occurring at the interface between a layer and a surrounding medium with lower refractive index.…”

“…High resolution projection microscopy in 1D [7] and 2D [8] has been demonstrated coupling x-ray WGs to laboratory tubes. However, quantitative phase retrieval using this configuration has not yet been achieved.…”

Characterization of thin films for X-ray and neutron waveguiding by X-ray reflectivity and atomic force microscopy

“…X-ray WGs have been thoroughly characterized using synchrotron X-rays [14,15] and have found numerous applications in high resolution microscopy [16] and coherent diffractive imaging [17]. In addition, increasing the efficiency of the WGs paved the way to demonstrating X-ray channelling for laboratory sources [10] and their application to sub-micron resolution microscopy in the laboratory [18]. The utilization of WGs with low brilliance X-ray sources suggests that similar applications could be developed for neutrons as well.…”

“…To this aim (i.e. using a neutron guided beam for subsequent studies) it is mandatory to increase the thickness of the guiding layer in order to increase the overall efficiency of the device [1,14,18]. As a consequence, a large number of modes can be simultaneously excited in the guiding layer and, depending on the source size and distance between source and waveguide, the overall coherence of the guided beam can be reduced [19].…”