JHU's Broholm examines the alignment of one of the 20 detection channels behind sample. Copyright Robert Rathe
NIST and Johns Hopkins University researchers have unveiled a new speedy and sensitive probe that may prove to be a godsend for nano scientists and related businesses. The NIST-JHU team calls the equipment a Multi-Axis Crystal Spectrometer. It is built on the technology developed in prior spectrometers at NIST’s Center for Neutron Research, where MACS is located, that bounce low-energy neutrons off of samples and then measure the specific directions and velocities of the scattered neutrons scatter. The previous spectrometers in this line, however, required large samples and had significant limitations regarding the test conditions. Nano researchers were frustrated by these early models because samples on the order of milligrams – the only amounts often available – are too small for this equipment. Further, testing material behavior in special environments, such as in the presence of magnetic fields, is usually impossible. The MACS system, however, allows for small samples and special test conditions. Further, MACS provides 20 different “channels” of detection rather than the single detector found in the older neutron spectrometers. Members of the MACS development team say the multi-channel feature could be thought of as a wide-angle, high-resolution lens:
“With previous instruments for inelastic scattering from magnetic materials, 80 milligrams is about the smallest sample you can work with,” says Collin Broholm, a professor at JHU. “But with MACS, we might be able to get detailed information about magnetic interactions even from a nanostructured thin film sample. These are the sort of interactions that nanotechnologists are trying to take advantage of when they design and shape things at the nanoscale.”
The NIST-JHU team is still tweaking MACS, but they anticipate that they will be able to issue a call for proposals to use the new spectrometer in about six months.