NOVEL SILICON DETECTORS FOR EXAFT STUDIES

用于 EXAFT 研究的新型硅探测器

• 批准号: 6519895
• 负责人: MICHAEL R. SQUILLANTE
• 金额: $ 37.95万
• 依托单位: RADIATION MONITORING DEVICES, INC.
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-01 至 2004-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6519895
• 关键词: X ray spectrometry; biomedical equipment development; electrodes; fluorescence; method development; radiation detector; silicon; synchrotrons

DESCRIPTION (Provided by Applicant): The availability of intense sources of synchrotron X-rays has made possible advanced studies of biological materials using the method of X-ray absorption spectroscopy (XAS). The advances, both in intensity as well as optics of these sources enables exploition of ultra-dilute spectroscopy and fluorescence QuEXAFS techniques [Farrow]. Current biophysical research utilizing these techniques includes studies of enzyme reactions, hemoglobin, and general study of metabolic processes. In these biological XAS studies, the experiments are now mostly limited by the X-ray detectors because they are not able to take full advantage of the available X-ray flux. Central to the design of modern XAS instrumentation is a very low noise X-ray detector, which must detect the fluorescence X-rays from the samples. It is important for the detector to operate with very high energy resolution and maintain that resolution at very high count-rates. Currently, germanium and lithium drifted silicon are the most popular detectors for XAS and EXAFS studies. Both these detector systems, while capable of excellent energy resolution, have some limitations. Si(Li) detectors have relatively high capacitance for larger sizes which increases their noise when operated at fast integration times. For High purity germanium (HPGe) detectors, the presence of Ge Ka fluorescence (9.876 keV) and the associated escape peaks in energy range of interest compromises the EXAFS data collection for hard X-ray experiments. In order to overcome these limitations, we propose to investigate a novel low capacitance detector design with high purity silicon as the detector material.

描述（由申请人提供）： 同步加速器X射线使生物材料的高级研究成为可能 采用X射线吸收光谱法（XAS）。这些进步，无论是在 这些光源的强度和光学特性使得能够利用超稀释的 光谱和荧光QuEXAFS技术[Farrow]。当前生物物理 利用这些技术的研究包括酶反应的研究， 血红蛋白以及代谢过程的一般研究。在这些生物XAS 研究，实验现在主要受到X射线探测器的限制，因为 它们不能充分利用可用的X射线通量。 现代XAS仪器设计的核心是非常低噪声的X射线 探测器，它必须探测来自样品的荧光X射线。是 重要的是探测器以非常高的能量分辨率工作， 在非常高的计数率下保持该分辨率。目前，锗和 锂漂移硅是XAS和EXAFS最常用的探测器 问题研究这两种探测器系统，虽然能够提供出色的能量， 分辨率，有一定的局限性。Si（Li）探测器具有相对高的 电容较大的尺寸，增加了他们的噪音时，在快速操作 整合时间对于高纯锗（HPGe）探测器， Ge Ka荧光（9.876 keV）和能量范围内的相关逃逸峰 的利益妥协的EXAFS数据收集硬X射线实验。 为了克服这些局限性，我们建议研究一种新的低 采用高纯硅作为探测器材料的电容探测器设计。