NEUTRON DETECTOR FOR PROTEIN CRYSTALLOGRAPHY

描述(申请人提供)：更好地理解蛋白质的三维结构在治疗疾病和开发新的治疗药物方面具有公认的价值。精确测量氢原子在分子中的位置是描绘这种结构，特别是分子的生物活性的核心。在结晶学技术中，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)定于2006年完工，它将使可用中子通量增加至少一个数量级，从而使实际晶体尺寸更小，采集时间显著减少。然而，目前所有中子成像探测器的规格都远远达不到此类设施所需的规格，危及这一尖端结晶学技术的实现。我们提出了一种新的位置灵敏中子探测器，它可以构成低成本、大面积探测器的基础，具有接近1 mm的优良空间分辨率和极高的计数率能力。这项提议的重点是减少物理秸秆探测器结构，该结构已经被证明在SNS的材料科学应用中是可行的，只需要5 mm的分辨率。在这一阶段的可行性研究中，将研究制造技术和结构材料，以实现绝对最小的探测器尺寸，从而实现最佳的分辨率。此外，还将在热中子束设施中进行模拟SNS操作的综合性能测试。在第二阶段，将建造一个50厘米×50厘米的全尺寸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.