A novel and ultra-sensitive 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 graded as to satisfy the diffraction condition everywhere on the multilayer. Such a multilayer array detector can be made with excellent energy selectivity (sufficient background rejection), large solid angle and fast time response. The first phase of the project is to test the concept, evaluate the detector performance, and fabricate a prototype detector with a single multilayer element and scintillator/PMT. A conceptual design of the fluorescence analyzer array detector will be generated based on the tests and analysis, which is essential for developing the detector into a marketable product in Phase II. The comparison of the proposed array detector with the currently operating fluorescence detectors, such as the 13-element Ge detector and ionization chamber, shows that the multilayer array detector is much more efficient when using a sample of a few mM in metal concentration. The advantages of the array detector become more evident under the conditions of increased flux and/or decreased sample concentration The detector will largely improve the detection efficiency for spectroscopy data collection at existing synchrotron sources, and it will provide tremendous opportunities for conducting the experiments either on time-resolved transient states or on very dilute systems at the third generation synchrotron sources. The cost for constructing the detector is well justified in view of the efficient increase and the Costs for building new beamlines.National Institute of General Medical Sciences (NIGMS)
