McMaster Small Angle Neutron Scattering Facility (MacSANS)
The McMaster Small Angle Neutron Scattering (MacSANS) beamline is nearing completion. When complete, SANS will be unique in Canada and will support more than 25 research groups at McMaster and other universities.
MacSANS will probe the structures of biomaterials and other materials with large molecules to study their properties on a length-scale up to 100 nm. This scale is appropriate for studying cellular membranes or nanoparticles. Steel processing companies have used SANS to characterize precipitates in their steel products as they develop products with enhanced strength and toughness to ensure the long-term reliability of pipelines and other steel structures. Until now, Canadians have had to go outside of Canada to use this technique.
A key component of the SANS facility is its subterranean guide-hall. This feature will allow researchers to maximize the distance between their samples and the detector, enabling them to accurately measure very small angles of diffraction that are otherwise too small to be observed.
Staff contact: Mitchell DiPasquale
McMaster Alignment Diffractometer (MAD)
Located on Beamport #6 in the McMaster Nuclear Reactor, the McMaster Alignment Diffractometer (MAD) is currently the only instrument in Canada capable of performing neutron diffraction and inelastic neutron scattering measurements.
MAD is a general purpose triple-axis spectrometer, primarily used for neutron diffraction measurements to align and evaluate the quality of single crystal and polycrystalline samples. MAD can also be used for more advanced characterization measurements such as: determination of crystal structures, identification of magnetically ordered ground states, characterization of phase transitions, and investigation of magnetic and vibrational dynamics (e.g. magnons and phonons). MAD is also available for educational use (e.g. demonstration experiments). MAD is built on the site of Bertram Brockhouse’s original McMaster triple-axis spectrometer, based on the same design that helped to earn Brockhouse the 1994 Nobel Prize in Physics.
Staff contacts: Pat Clancy and Bo Yuan.
Powder diffractometer
A new powder diffractometer is being designed for MNR. Powder diffractometers are some of the most prolific neutron instruments. They are in high demand for determining the chemical and magnetic crystallography of new materials and for establishing structure-property relationships and phase behaviour in a broad range of hard materials.
We will build a new instrument optimized to collect diffraction patterns over a 120° horizontal scattering angle (and 11° vertically) using a two-dimensional position-sensitive detector filled with 3He gas. Geometric calculations show that its data collection rates will be at least as good as, if not better than, the C2 instrument.
The instrument will be essential for many Canadian research programs. For example, powder neutron diffraction is the only technique for locating hydrogen in the unit cell of metal hydrides during in situ studies of hydrogen absorption and desorption, which is critical to determining how the metal alternates between hydrided and dehydrided phases. It is essential for solving the crystal and magnetic structures that produce the behaviours of thermoelectric and magnetocaloric materials and of permanent magnets that enable more energy-efficient technologies. It is essential for observing the locations of small ions in battery electrodes; determining the influence of minority alloying elements on strength; and observing the way that texture is inherited through phase transformations. It also is central to understanding how the chemical and magnetic structures relate to the electrical and magnetic properties in many quantum materials.
Stress-scanner
The L3 neutron stress-scanner is being relocated to MNR from the Canadian Neutron Beam Centre (CNBC). Neutron stress-scanners are frequently used by industry and university-industry collaborations to determine internal stresses in metallic parts that are safety-critical components of a structure, machine, or vehicle. The stress-scanner at the CNBC was used for most of this research in Canada until the CNBC closed in 2018. This instrument offers submillimetre sampling volume and is optimized for precise measurements of lattice strain (±1×10-4) as a function of position (±10 μm) within engineering components.
Neutron stress-scanning is the only non-destructive means to determine stresses deep within the same metallic part (e.g. components of a car or boat engine) both before and after it undergoes manufacturing processes such as heat treatment for relieving stress. It is often the only means to observe how stresses relax in alloys at elevated temperatures, which is needed to understand how materials behave around flaws (e.g. small cracks) in nuclear reactor components and hence to predict safe operating margins of power plants.
Reflectometer
The D3 reflectometer is being relocated to MNR from the CNBC. Neutron reflectometers are high-demand instruments, typically oversubscribed by factors of 2 to 3. Due to an ever-increasing interest in the industrial applications of thin films and membranes, neutron reflectometry will continue to be an essential research tool well into the future. MNR’s reflectometer is optimized for determining chemical and magnetic profiles as a function of depth into the surface of materials fabricated as thin films or multilayers.
The reflectometer enjoyed a multidisciplinary user base at the CNBC. Neutron reflectometry is the only technique that has enough sensitivity to hydrogen atoms to determine the amounts and locations of hydrogen in copper coatings, and to track changes in these parameters non-destructively and in situ under changing physical, electrochemical, and environmental conditions. It is essential for developing bio-nanotechnologies for which understanding polymer coatings on surfaces or water-polymer interactions is critical, such as nanocellulose for reinforcement applications, or anti-biofouling coatings for medical implants, tests, and sensors. It is also essential for identifying skyrmions in thin films of quantum magnetic metals.