An Energy-Resolving X-ray Fluorescence Detection System

提出了一种能量分辨X射线荧光探测器系统。检测器系统使用的概念，选择从弹性散射的背景，从合成多层衍射的X射线荧光。多层膜将被线性渐变，以满足多层膜上各处的衍射条件。初步评估表明，这种探测器可以制成具有良好的能量分辨率（足够的背景抑制），大立体角，和快速的时间响应。该项目将分两个阶段进行。该项目的第一阶段是模拟这种探测器的性能，并制造具有3-4个多层元件的原型探测器。基于第一阶段的结果，第二阶段将开发包含40个多层元件的多层分析器阵列探测器。该探测器将由各种金属蛋白的研究小组进行测试和使用。由于使用渐变合成多层膜的荧光能量选择，据我们所知，是一个原创的想法，我们试图拿出更详细的设计和程序。所提出的检测器的性能的评价表明，它是更有效的比目前运行的检测器，如13元素锗检测器和电离室，收集数据时，使用几个mM的样品的偏转磁铁束线。阵列探测器的优点在光子通量增加和/或样品浓度降低的条件下变得更加明显。该探测器将为在第三代同步加速器源（如APS）上进行时间分辨瞬态或非常稀的系统的XAFS实验提供巨大的机会。该探测器将大大有利于P.I.的研究项目。以同样的方式，大大提高了效率和数据质量。然而，由于篇幅限制和本提案的性质，没有讨论这些项目的科学方面。构造探测器的成本与购买13元Ge探测器的成本相当，并且鉴于有效增加和建造新光束线的成本是合理的。此外，还计划长期运行和维护（见第I节）。特殊信息），以确保广大潜在用户在探测器的使用寿命期间都能使用探测器。

An energy-resolving x-ray fluorescence detector system has been proposed. The detector system uses the concept of selecting x-ray fluorescence from an elastically scattered background by the diffraction from a synthetic multilayer. The multilayer will be linearly graded as to satisfy the diffraction condition everywhere on the multilayer. Preliminary evaluation shows that such a detector can be made with a good energy resolution (sufficient background rejection), large solid angle, and fast time response. The project will be carried out in two phases. The first phase of the project is to simulate the performance of such a detector and to fabricate a prototype detector with 3-4 multilayer elements. Based on the results of Phase I, a multilayer analyzer array detector containing 40 multilayer elements will be developed in Phase II. The detector will be tested and used by research groups on various metalloproteins. Since the use of graded synthetic multilayers for fluorescence energy selection, to our knowledge, is an original idea, we try to come up with more detailed designs and procedures. The evaluation of the performance of the proposed detector shows that it is more efficient than the currently operating detectors, such as the 13-element Ge detector and ionization chamber, when collecting data on a bending magnet beamline using a few mM sample. The advantages of the array detector become more evident under the conditions of increased photon flux and/or decreased sample concentration. The detector will provide tremendous opportunities for conducting XAFS experiments either on time-resolved transient states or on very dilute systems at third generation synchrotron sources, such as the APS. The detector will greatly benefit the research projects of the P.I. in the same fashion by largely improved efficiency and data quality. However, due to the page limitation and the nature of this proposal, the scientific aspects of these projects are not discussed. The cost for co nstructing the detector is comparable to the cost for purchasing a 13-element Ge detector, and is well justified in view of the efficient increase and the cost for building new beamlines. In addition, long term operation and maintenance are planned (see Section I. Special Information) to insure the access of a wide circle of potential users to the detector through its useful life.