The Uncertainty Researches Based On Analysis Of Micro Beam Micro Area X Fluorescence Probe

Micro beam and micro area X fluorescence probe is a novel geographical mineral-detecting instrumentation that was developed recently for the urgent demand of acquiring the mineral composition. This mineral probe combined micro X-ray generator and X-ray lens as micro beam X-ray source, and it set room-temperature semiconductor as X-ray detector, metallographic microscope and CCD camera were chosen to the visual sample micro platform, it adopted fully digital rays collector and its corresponding software to achieve the collection and analysis of characteristics measured X-ray spectroscopy, all of these preparations were for the multi-element microscopic qualitative analysis of mineral compositions and quantitative analysis tasks under the condition of indoor and outdoor. The micro area focal spot diameter of mineral probe is (30-50) um, there was no need to slice, polish, coat the samples, and the diameter is suitable to the analysis of the crystal or microcrystalline mineral composition of samples of rock, soil, atmospheric particulates, blocked material and so on, the range of elements analyzed were from sulfur (S) to uranium (U).This paper adopted class A uncertainty evaluation method and class B uncertainty assessment method, and consulted the requests of "the law of the People’s Republic of China national metrology count specifications JJF1059.1-2012measurement uncertainty evaluation", the uncertainty researches of the results of micro beam micro area X fluorescence probe measurements were performed, which was good for the instrumentation will be popularized in the application of geological survey. The research results in this paper are as following:1. According to the working principles and processes of micro beam micro area X fluorescence probe, the resources of class A uncertainty and class B uncertainty in mineral probe instrumentation were systematically analyzed as well as their possible effect factors.2.Geochemical reference materials were adopted and the results of Ti, Fe, Cr, Mn, Cu, Zn, Ca and other elements’uncertainty in the original system were as following: CTi=(6341±299)μg/g,k=2; CFe=66920±2688)μg/g,k=2 CCr=(138±41) μg/g,k=2； CMn=(999±156)μg/g,k=2CCu=(171±30)μg/g,k=2；CZn=(225±28)μg/g,k=2CCa=(20571±2821)μg/g,k=23.By using the anallysis of main compositions to obtain the best measurement conditions of the instrumentation:number of measurement:7,time of measurement:160s,focal spot diameter:40um,tube voltage:30kV, current of measured tube:1uA.