Vol. 12, no.2, 2020


Track membranes and their replicas as high-frequency phase-contrast objects in x-ray optics

Alexander V. Mitrofanov

Lebedev Physical Institute of RAS, https://lebedev.ru/
Moscow 119991, Russian Federation
E-mail: mitrofanovav@lebedev.ru
Alexey V. Popov, Dmitry V. Prokopovich
Pushkov Institute of Terrestrial Magnetism, Ionosphere and Propagation of RAS, https://izmiran.ru/
Troitsk, Moscow 142192, Russian Federation
E-mail: popov@izmiran.ru, dvprokopovich@gmail.com

Received December 10, 2019; peer reviewed April 07, 2020; accepted April 10, 2020
Abstract. The paper discusses the possibility of using polymer track membranes with through pores, as well as membrane replicas as elements of x-ray optics for experiments on the visualization of micro-objects with high spatial resolution. It was shown that samples prepared on the basis of track membranes and their replicas can be used in a wide x-ray range, including in the soft spectral region (λ ≥ 1 nm) as phase screens and as simple model phase test objects for X-ray microscopy. Highly porous membranes as diffuse weakly absorbing samples in the form of a single layer or stack of several films affect the coherent properties of the primary x-ray beam. The optical constants of the material of existing porous membranes, their thickness, density and pore size allow you to vary the optical characteristics of the phase screens in a wide frequency range, including the visible region of the spectrum and the X-ray range, in which many sources of synchrotron radiation operate. The paper investigates in detail the field concentration by phase structures with narrow through channels in the films, the effect of pore diameter on the phase wave velocity in the channels, and the spreading (in the transverse plane) of the phase picture of the field for membranes with extremely narrow pores, which limits the resolution of the phase screen, used as an x-ray test object. Numerical experiments were performed by solving the parabolic equation using tabular values of the optical constants for the membrane material.

Keywords:X-ray optics, phase-contrast X-ray microscopy, phase test nano-objects, track membranes, parabolic equation method in X-ray optics

PACS 41.50.+h, 41.60.Ap, 02.60.Cb

RENSIT, 2020, 12(2):173-190. DOI: 10.17725/rensit.2020.12.173.

Full-text electronic version of this article - web site http://en.rensit.ru/vypuski/article/332/12(2)173-190e.pdf