Using Convergent Beams for Small-Sample, Time-of-Flight Neutron Diffraction

70146S02-II Neutron diffraction is an important tool for the structural analysis of molecules. However, limitations on available beam intensities can lead to long or even impractical measurement times when only small samples are available. This project will develop technology for focusing neutron beams using polycapillary optics to provide greatly increased intensity and reciprocal space sampling. This would enable faster measurements, measurements of crystalline materials that are only available in small samples, high-pressure studies, and mapping. In Phase I, feasibility was demonstrated for both single-crystal and powder diffraction. A 10-100 times increase in diffracted intensity was demonstrated while maintaining sufficient peak resolution. Phase II will design and fabricate customized optics for the range of relevant neutron instruments. Studies will be conducted on the Single Crystal Diffractometer (SCD) and General Purpose Powder Diffractometer (GPPD) to determine the benefits and limits of the technique. Measurements will be made for small samples, high pressures, and mapping of heterogeneous samples. Commercial Applications and Other Benefits as described by awardee: In addition to the application for neutron beam lines, the convergent beam technique should find use in x-ray diffraction and medical x-ray optics, leading to faster and more effective development efforts for new drugs and other materials.