New modality introduces energy-resolved imaging to existing facility in Australia.
From: American Institute of Physics Scilights online publication, April 26, 2019
By Mark Marchand
Neutron-scattering techniques can peer deep into materials to conduct advanced, non-destructive imaging studies, making them especially attractive for examining historic artifacts, geological specimens, and critical metal welds. It is also unique because many materials are opaque to X-rays and other imaging techniques based on electrons or photons.
A new paper reports enhancements to an existing neutron-scattering instrument by adding a new modality to “Bilby,” a Small Angle Neutron Scattering (SANS) instrument at Australian Centre for Neutron-Scattering (ACNS), to enable energy-resolved neutron imaging experiments. SANS is a neutron scattering technique tuned to investigate the collective internal structure and composition on a scale between 1 to 100 nanometers.
According to the authors, the new capability of Bilby is enabled by placing a recently developed neutron-counting detector between the sample and the vacuum chamber containing the main SANS detectors. The new detector can measure up to 250,000 neutron transmission spectra per experiment.
They tested the new setup with multiple samples, including an ancient Japanese sword, or katana. Using the new modality, the team was able to depict where two steel components were welded together in laminated structures, a typical technique for making the Japanese swords. The capability will be useful for those seeking more in-depth scientific analysis of cultural artifacts as old as 1,000 years. The team also believes that the cold neutron spectrum instrument at ACNS is well fitted for crystallographic analysis by taking images at wavelengths near what is known as the last Bragg edge, appearing between 4 to 6 angstroms for many engineering materials.
By adding the capability to Bilby, the system becomes one of the few neutron-scattering facilities able to conduct such sophisticated neutron imaging.
Source: “Energy resolved neutron-imaging options at a small angle scattering instrument at the Australian center for neutron scattering,” by A. S. Tremsin, A. V. Sokolova, F. Salvemini, A. Paradowska, O. Muranksy, H. J. Kirkwood, B. Abbey, C. M. Wensrich, and E. H. Kisi, Review of Scientific Instruments (2019). The article can be accessed at https://doi.org/10.1063/1.5081909.