High Efficiency X-ray Fluorescence Detectors

描述（由申请人提供）：在各种报告和研讨会[1-2]中反复强调，迫切需要开发更好的X射线荧光检测器系统，以解决当前可用检测器的饱和问题。采用线性渐变多层膜的多层膜分析器阵列探测器（MAAD）已成功地用于处理来自第三代同步辐射光源的大光子通量。然而，这种类型的探测器受到其垂直和水平接受度的限制，具有有限的探测立体角。如果水平接收角增大，探测器的能量分辨率将大大降低，吞吐量也将损失。在第一阶段的建议，我们已经提出了开发多层阵列分析仪检测器使用径向梯度多层。通过大大增加每层的水平接受度，这种新设计提供了2.5倍的收集立体角增加。此外，由于优选的梯度设计和优化的沉积材料选择，新设计大大降低了能量分辨率并提高了分析仪的吞吐量。因此，我们已经证明了6-8倍的综合性能提高比以前的分析器检测器设计。在我们的第二阶段项目（RR 015994）完成后的后续研究中，我们证明了采用双多层分析仪的正配置（而不是我们之前提出的负配置）可以实现超过10，000的大背景抑制。因此，我们将联合收割机结合两种技术，即径向分级多层技术和新的双层多层分析仪配置，以制造非常理想的荧光分析仪检测器，使用户群体受益。在第二阶段的项目中，我们将设计，制造和测试一个径向梯度多层阵列分析仪探测器（RMAAD）优化的能量从1.2至4千电子伏，和一个双重多层阵列分析仪探测器（DMAAD）的正配置优化从3.5至10千电子伏。我们将采用模块化设计的RMAAD单元，其中包含5个miltilayers的较小单元可以添加到形成一个全尺寸单元。当不需要大的背景抑制时，DMAAD单元可以作为RMAAD工作。拟定的DMAAD将允许以ppb水平或生理相关浓度进行元素检测。除了提高检测效率外，所提出的分析仪检测器还在两个关键领域扩展了当前的荧光检测能力：非常稀的系统状态和与生物学最相关的中间到较低能量区域。新探测器的市场将不再局限于具有强通量的同步加速器光束线，而是涉及光谱和荧光分析的所有光束线。在这一建议中所取得的进展将提高在当前和下一代同步辐射源可实现的高计数率下的X射线光谱和荧光分析的研究能力。

DESCRIPTION (provided by applicant): It has been repeatedly emphasized in various reports and workshops [1-2] that the development of better X- ray fluorescence detector systems is urgently needed to solve the saturation problems with the currently available detectors. The multilayer analyzer array detector (MAAD) using linearly graded multilayers has been successfully developed to handle the large photon flux from the third generation synchrotron sources. However, this type of detectors has limited detection solid angle restricted by its vertical and horizontal acceptance. The detectors will suffer largely degraded energy resolution and loss of throughput if horizontal acceptance angle is increased. In the Phase I proposal, we have proposed to develop multilayer array analyzer detectors using radially graded multilayers. By largely increasing the horizontal acceptance per multilayer, this new design provides a 2.5 times of collection solid angle increase. Furthermore, the new design substantially reduces the energy resolution and improves the throughput of the analyzers due to the preferred gradient design and optimized deposition material selection. Thus we have demonstrated 6-8 times of combined improvement of performance over the previous analyzer detector design. In a subsequent investigation after the completion of our Phase II project (RR015994), we have demonstrated that large background rejection, in excess of 10,000, can be achieved with a dual multilayer analyzer in }plus} configuration, rather than }minus} configuration that we have proposed previously. Thus we will combine the two technologies, namely the radially graded multilayer technology and the new dual multilayer analyzer configuration to fabricate very desirable fluorescence analyzer detectors to benefit the user community. In the Phase II project, we will design, fabricate and test one radially graded multilayer array analyzer detector (RMAAD) optimized for energies from 1.2 to 4 KeV, and one dual multilayer array analyzer detector (DMAAD) in the plus configuration optimized from 3.5 to 10 KeV. We will adopt a modular design for the RMAAD unit, where smaller unit containing 5 miltilayers can be added to form a full-scale unit. The DMAAD unit can work as a RMAAD when large background rejection is not required. The proposed DMAAD will allow for the elemental detection in ppb levels or in Physiologically relevant concentrations. In addition to the improved detection efficiency, the proposed analyzer detectors extend the current fluorescence detection capability in two crucial areas: very dilute system regime and intermediate to lower energy regions, which are most relevant to biology. The market of the new detectors will no longer be restricted to synchrotron beamlines with intense flux, but all the beamlines which are involved in spectroscopy and fluorescence analysis. The advances made in this proposal will enhance the capability of research for x-ray spectroscopy and fluorescence analysis under high count rate achievable at the current and next generation synchrotron sources.