Where is the Hydrogen?

How is hydrogen distributed among minerals and how is it bonded in their crystal structures? These are important questions, because the amount of hydrogen and the bonding configuration of hydrogen in crystalline materials governs many of that material’s properties: its thermal and compressional behavior, P–T phase stability, rheology, and electrical conductivity. A reliable reconstruction of the Earth’s interior, or the prediction of mineral transformations in complex industrial processes, must account for these parameters. Neutron diffraction can locate hydrogen sites in mineral structures, reveal any static or dynamic hydrogen disorder, help define the libration regime of hydrogen, and elucidate hydrogen-bonding configurations. Thus, that most elusive element for X-ray probes is perfectly detectable using neutrons.

Read More

Neutrons “101” – A Primer for Earth Scientists

The fundamental properties of the neutron make it a powerful tool for Earth science investigations because neutrons provide information that cannot be obtained by any other research method. This is because neutrons are magnetically sensitive, nondestructive, and sensitive to the lighter elements, such as hydrogen. They provide a unique, nondestructive method for obtaining information ranging from Ångstrom-scale atomic structures (and related motions) to micron-scale material strain, stress, and texture, and even up to meso-scale porous matrices and defects in materials and functional components. In this article, we introduce neutrons and their unique properties, neutron production and sources, and provide an overview of the different types of neutron methods applicable to the Earth sciences.

Read More