Structure-aided drug design requires state-of-the-art crystallography to understand the relationship of protein structure to its function in disease causing organism to lead the way in designing novel effective drugs without any side effects. Neutron diffraction provides a unique approach to investigate the structural biology by determining the position of hydrogen atoms, which are critical to structural stability and effective function but are unobservable by X-rays. The objective of the proposed program is to develop a new solid-state, large-area, and position sensitive neutron detector based on boron-doped amorphous selenium for macromolecular neutron crystallography. The detector would offer high spatial resolution, high detection efficiency, fast response and reset time, excellent gamma discrimination, and high radiation hardness. The proposed detector would be inexpensive for industrial mass production. The Phase I project will focus on zone-purification of Se precursors, synthesis of heavily B-doped (up to 32.4 atomic %) a-Se (As, CI) alloys, detector design and fabrication, and performance evaluation at Spallation Neutron Source (SNS), Oak Ridge National Laboratory (ORNL). The developed detectors would find widespread use in neutron diffraction for structural biology, neutron scattering research, nuclear non-proliferation and in high priority national program of Homeland Security.