A novel 3D printed radial collimator for x-ray diffraction

In Situ and Operando X-ray Scattering Methods in Electrochemistry and Electrocatalysis

Electrochemical and electrocatalytic processes are of key importance for the transition to a sustainable energy supply as well as for a wide variety of other technologically relevant fields. Further development of these processes requires in-depth understanding of the atomic, nano, and micro scale structure of the materials and interfaces in electrochemical devices under reaction conditions. We here provide a comprehensive review of in situ and operando studies by X-ray scattering methods, which are powerful and highly versatile tools to provide such understanding. We discuss the application of X-ray scattering to a wide variety of electrochemical systems, ranging from metal and oxide single crystals to nanoparticles and even full devices. We show how structural data on bulk phases, electrode-electrolyte interfaces, and nanoscale morphology can be obtained and describe recent developments that provide highly local information and insight into the composition and electronic structure. These X-ray scattering studies yield insights into the structure in the double layer potential range as well as into the structural evolution during electrocatalytic processes and phase formation reactions, such as nucleation and growth during electrodeposition and dissolution, the formation of passive films, corrosion processes, and the electrochemical intercalation into battery materials.

Computational optimization of a 3D printed collimator

This contribution describes the computational methodology behind an optimization procedure for a scattered beam collimator. The workflow includes producing a file that can be manufactured via additive methods. A conical collimator, optimized for neutron diffraction experiments in a high pressure clamp cell, is presented as an example. In such a case the scattering from the sample is much smaller than that of the pressure cell. Monte Carlo Ray tracing in MCViNE was used to model scattering from a Si powder sample and the cell. A collimator was inserted into the simulation and the number and size of channels were optimized to maximize the rejection of the parasitic signal coming from the complex sample environment. Constraints, provided by the additive manufacturing process as well as a specific neutron diffractometer, were also included in the optimization. The source code and the tutorials are available in c3dp (Islam (2019)).

Stacking of micro-aperture arrays: A new strategy to construct Söller collimator for x rays

A stacking strategy to construct a light-weight collimator is proposed in this paper by which micro-aperture arrays can be assembled as a novel Söller collimator. Compared to Söller collimators made from conventional methods, our strategy enabled a substantial mass reduction up to 67% for a field of view of 2°. 21 micro-aperture arrays were fabricated by fiber laser drilling, and the Söller collimator was thereafter afforded by stacking and aligning the arrays. The processing consistency of the arrays and the alignment of the assembled collimator were examined by optical microscopy and x-ray computer tomography. Collimation tests were conducted to evaluate the feasibility of the stacking strategy. Based on this new strategy, higher aspect ratios can be fulfilled, which also allows for a significant mass reduction compared to the conventional Söller collimator.