An Energy-Resolving X-ray Fluorescence Detection System

能量分辨 X 射线荧光检测系统

• 批准号: 9419635
• 负责人: Ke Zhang
• 金额: $ 54.88万
• 依托单位: University City Science Center
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-02-15 至 1999-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9419635&HistoricalAwards=false
• 关键词: Energy; Resolving; ray; Fluorescence; Detection

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.

提出了一种能量分辨的X射线荧光探测系统。该探测器系统使用了通过合成多层膜的衍射从弹性散射背景中选择X射线荧光的概念。多层膜将线性渐变，以满足多层膜上所有位置的衍射条件。初步评价表明，这种探测器具有较好的能量分辨率(足够的背景抑制)、较大的立体角和较快的时间响应。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，并制作一个具有3-4个多层元件的原型探测器。在第一阶段结果的基础上，第二阶段将开发一个包含40个多层元素的多层分析器阵列探测器。该探测器将被各种金属蛋白研究小组测试和使用。由于使用分级合成多层膜来选择荧光能量，据我们所知，是一个原创性的想法，我们试图提出更详细的设计和程序。对该探测器性能的评估表明，在使用几mm样品在弯曲磁铁光束线上采集数据时，该探测器比目前使用的13元Ge探测器和电离室等探测器更有效。在光子通量增加和/或样品浓度降低的情况下，阵列探测器的优势变得更加明显。该探测器将为进行XAFS实验提供巨大的机会，无论是在时间分辨的暂态上，还是在第三代同步加速器源(如APS)的非常稀薄的系统上。该探测器将以同样的方式极大地提高效率和数据质量，从而极大地有利于P.I.的研究项目。然而，由于篇幅的限制和这项提案的性质，这些项目的科学方面没有得到讨论。建造探测器的成本与购买13个元素的Ge探测器的成本相当，考虑到有效增加和建造新光束线的成本，这是很合理的。此外，还计划长期运行和维护(见第一节特殊信息)，以确保广泛的潜在用户在探测器的使用寿命内都能接触到它。