High-pressure cell for in situ neutron studies of hydrogen storage materials

Abstract

A high-pressure cell for neutron experiments was developed at Helmholtz-Zentrum Geesthacht (HZG). This cell is designed for the investigation of hydrogen storage materials at pressures up to 700 bar and temperatures up to 500°C. The idea is to have a prototype cell for different neutron scattering methods (diffraction, time-of-flight spectroscopy and small-angle neutron scattering). In this work, we discuss the development and the current state of the high-pressure cell. Furthermore, the deployment of the cell for in situ small-angle neutron scattering measurements on 6Mg(NH 2) 2 + 9LiH + LiBH 4 (6:9:1) at the instrument SANS-1 at Heinz Maier-Leibnitz Zentrum (MLZ) is demonstrated.

Computation of X-ray and Neutron Scattering Patterns to Benchmark Atomistic Simulations against Experiments

“…Together with the proposed method to alleviate a finite size effect visible in the small-angle region, this makes it possible to compute scattering patterns from nanoscopically structured samples and validate them against experimental scattering data. We plan to use this for explaining in situ neutron scattering studies of nanoscopically sized hydrogen storage materials [97]. The computation algorithm of Sassena is designed in such a way that it calculates the amplitude of the scattered wave at its core.…”

Operando reaction cell for high energy surface sensitive x-ray diffraction and reflectometry

“…Measurements were performed utilizing pressures of up to 50 bars of Ar, H 2 , CO, and CO 2 with sample temperatures of up to 600 K. While the pressure and temperature limits of the capillary itself were not tested in this proof-of-concept study, similar cell geometries point toward pressure ranges of up to several hundred bars. 24…”

“…The main concept of the instrument is based on a single crystalline Al 2 O 3 capillary, which acts as both the gas pressure cell and the window for hard x rays. This material was chosen as it has proven to withstand pressures of up to 700 bars at 770 K 24 and is sufficiently transmissive for a high energy synchrotron beam with, e.g., hν = 73 keV (see Fig. 1).…”