Improved understanding of the three-dimensional structure of proteins is of well-recognized value in the treatment of disease and in the development of new therapeutic drugs. Precise measurement of hydrogen atom position within the molecule is central to delineation of such structure and particularly the biological activity of the molecule. Among crystallography techniques, single crystal neutron diffraction (SCD) has the unique ability to provide this information. A major national facility (Spallation Neutron Source, SNS) is due for completion in 2006 and will increase available neutron flux by at least an order of magnitude, thereby enabling practical small crystal size and markedly decreased acquisition times. However, specifications of all current neutron imaging detectors fall far short of those needed at such a facility, jeopardizing the realization of this cutting edge crystallographic technique. We propose a novel position-sensitive neutron detector that can form the basis of a low-cost, large area detector with excellent spatial resolution approaching 1 mm and the exceedingly high count rate capability required. This proposal focuses on reduction of the physical straw detector structure already proven to be feasible for materials science applications at SNS, which require only 5 mm resolution. In this Phase I feasibility study, fabrication techniques and materials of construction will be investigated in order to achieve the absolute minimum detector size and therefore the best possible resolution. In addition, comprehensive performance testing simulating operation at SNS will be performed at a thermal neutron beam facility. In Phase II, a full-scale 50 cm x 50 cm prototype detector panel will be constructed and successfully operated. ? ?
