MULTILAYER ANALYSER FOR XAFS: X RAY FLUORESCENCE DETECTOR

该项目的目标是开发能量分辨x射线 使用合成多层膜的荧光检测器。 20个元素 使用渐变多层膜的多层阵列探测器在 BioCAT光束线 这些元素彼此相对对齐 使用微调机制。 检测器校准曲线 通过旋转衍射平面上的所有元素获得 具有固定的光束入口狭缝。 检测器的吞吐量为 约26%。 获得了类似的检测器通量 当在其他荧光能量下校准时，例如Mn、Co、Cu和 Zn，具有基本上相同的吞吐量。 该探测器在 稀释的生物系统。 信号背景比为 大约5比1，而没有信号背景比， 分析仪为1到3。 因此，总的拒绝率约为15 次 为了提高分析器检测器的吞吐量，我们 仔细选择与多层沉积相关的因素， 特别是影响反射率的因素。 24元素 分析器阵列探测器已经设计并正在制造中。 与20元件单元类似，总检测立体角为 0.21在Mn Ka和Zn Ka荧光能量为0.14。 检测均 安装了7个元件的单元显示吞吐量为35%， 比20个元素的单位更好。 这个新单位将完成， 半年内试运行。

The objective of the project is to develop energy-resolving x-ray fluorescence detectors using synthetic multilayers. A 20-element multilayer array detector using graded multilayers was fully tested at the BioCAT beamline. The elements were aligned relative to each other using the fine adjustment mechanism. The detector calibration curve was obtained by rotating all the elements in the diffraction plane with a fixed beam entrance slits. The throughput of the detector is approximately 26%. Similar throughput of the detector was obtained when calibrated at other fluorescence energies, such as Mn, Co, Cu and Zn, with essentially the same throughput. The detector was tested on dilute biological systems. The signal to background ratio is approximately 5 to 1, while the signal to background ratio without the analyzer is 1 to 3. Thus the total rejection rate is approximately 15 times. To improve the throughput of the analyzer detector, we have carefully chosen the factors relative to multilayer deposition, in particular the factors affecting the reflectivity. A 24-element analyzer array detector has been design and are being fabricated. Similar to the 20-element unit, the total detection solid angle is 0.21 at Mn Ka and 0.14 at Zn Ka fluorescence energies. Tests on the unit with 7-elements installed show that the throughput is 35%, much better than the 20-element unit. This new unit will be completed and tested for operation within half year.