Patent ID: 7809103
Filing Date: 2010-10-05
Classification: G01N

Abstract:
1. A method for inspecting an article comprising a plurality of elements, wherein one element is selected as a background element, the method comprising: irradiating the article with radiation comprising a first energy and a second energy; receiving data that corresponds to the first energy and the second energy; processing the data to generate a first data set and a second data set; wherein the first data set corresponds to the first energy and wherein the second data set corresponds to the second energy; obtaining an attenuation ratio for the background element present in the article; the attenuation ratio for the background element being an attenuation in energy produced by the background element at the first energy to an attenuation in energy produced by the background element at the second energy; subtracting the attenuation ratio for the background element at the second energy from a product of the attenuation ratio for the background element with the first energy data set to form a filtered data set; identifying a region of interest in the filtered data set; and calculating an effective atomic number from the filtered data set for elements that have an atomic number greater than the background element in the region of interest.