Neutrons are a unique probe of the structure and dynamics for a great variety of systems studied today in many scientific disciplines. With the construction of the Low Energy Neutron Source (LENS) at ISAT Hall, potential users in non-traditional fields such as chemistry and biology and industrial researchers can be made familiar with the power of neutron scattering techniques and acquire the experience needed to perform critical experiments of relevance to their fields. Major obstacles to expanding the neutron community in this country are the existing general unfamiliarity of US researchers with neutron techniques, a diminishing number of national and local facilities where novice users may be introduced to neutron scattering techniques, and the lack of flexible facilities for engineering and technical studies where new ideas for neutron science and engineering can be pursued. The variable pulse width offered by our source, its low cost, and its greatly reduced level of background radiation, put it in a unique position to have an impact on education and emergent technologies such as biomolecular engineering, chemistry, moderator development and instrumentation design.
LENS Moderator Development
The Low Energy Neutron Source (LENS) produces cold neutron beams for fundamental and applied research using relatively low energy (7-13 MeV). The facility is capable of characterizing any moderator prototype that can fit within the existing 50cm diameter/50 cm tall cylindrical water reflector volume. The slab geometry, tight coupling, and cold temperature utilized in the LENS moderator will make the facility an important testing ground for a number of technologies that may be used in future high-power neutron scattering facilities. Furthermore, the low proton energy used will result in sufficiently low activity in the target/moderator system for materials to be handled without extensive remote handling facilities which is important for its use as an educational resource.
Ultracold Neutrons
Dr. Chen-Yu Liu is pursuing ultra-cold neutron (UCN) production in solid oxygen. The physics of UCN production in solid oxygen involving magnon (spin wave) exchanges is fundamentally different from the well-known phonon mechanism in solid deuterium. In solid deuterium sources, the finite concentration of para-deuterium (spin 1) can retain unquenched rotational energy even at low temperatures. This effect results in excessive upscattering of neutrons out of the ultracold state. The greatly enhanced solid oxygen UCN flux will enable a comprehensive set of studies on UCN production physics.
