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McMaster University

Brockhouse Institute Seminar

SPEAKER Helmut Fritzsche, Canadian Nuclear Laboratories, Chalk River, Canada
TOPIC Probing the hydrogen absorption properties of Mg-based alloys using in-situ neutron reflectometry 

Thin films offer a unique opportunity to study the fundamentals of hydrogen absorption and desorption in great detail because nanoscale layers can be prepared with well-defined composition and thickness. Neutron Reflectometry (NR) is capable to determine the chemical depth profile of thin film samples from the subnanometer regime up to about 200~nm thickness with nm resolution. The high sensitivity of neutrons to hydrogen and deuterium enables NR to detect absolute hydrogen concentrations in the at.% range even in nm-thick layers. Therefore, NR is an ideal tool to study in-situ the hydrogen/deuterium absorption and desorption properties of thin films on a nanometer scale - without the need of a calibration sample. By using thin films as model systems makes it possible to e.g. discriminate between the catalytic surface effect of a cap layer on top of a Mg film and the catalytic bulk effect of alloying the Mg film with other elements. This presentation shows how NR can be used to determine in-situ the hydrogen profile within a thin film system and how this knowledge can be used to better understand the hydrogen absorption properties of Mgbased alloys.

Dr. Helmut Fritzsche, Editor of the book “Neutron Scattering and Other Nuclear Techniques for Hydrogen in Materials”, is a senior researcher at the Canadian Nuclear Laboratories in Chalk River. He received his Ph.D. in 1995 from the Technical University Clausthal, Germany and then worked first as a postdoc and later as a researcher at the Hahn-Meitner-Institut in Berlin, Germany. He moved to Chalk River, Canada, in 2003 accepting a position as research officer with the National Research Council Canada before joining CNL in 2015. Since his Ph.D. Dr. Fritzsche has been applying neutron scattering techniques to study surface and interface related phenomena in thin films.

DATE Monday, April 03, 2017
TIME 3:30 pm

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