NEUTRON DETECTOR FOR PROTEIN CRYSTALLOGRAPHY

描述（由申请人提供）：提高对蛋白质三维结构的理解在疾病治疗和新治疗药物的开发中具有公认的价值。分子内氢原子位置的精确测量对于描述这种结构，特别是分子的生物活性至关重要。在晶体学技术中，单晶中子衍射（SCD）具有提供这种信息的独特能力。一个主要的国家设施（散裂中子源，SNS）将于2006年完工，将使可用的中子通量至少增加一个数量级，从而实现实际的小晶体尺寸，并显著减少采集时间。然而，目前所有中子成像探测器的规格远远达不到这种设施所需的规格，危及了这种尖端晶体学技术的实现。我们提出了一种新的位置敏感中子探测器，它可以构成低成本的基础，大面积探测器具有接近1毫米的优异空间分辨率和极高的计数率能力。该提案的重点是减少物理吸管探测器结构，这种结构已经被证明在SNS材料科学应用中是可行的，只需要5毫米的分辨率。在第一阶段的可行性研究中，将研究制造技术和建筑材料，以实现绝对最小的探测器尺寸，从而获得最佳的分辨率。此外，SNS的综合性能测试模拟操作将在热中子束设施上进行。在第二阶段，将建造一个全尺寸50厘米x 50厘米的原型探测器面板并成功运行。

DESCRIPTION (provided by applicant): 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.