Patent ID: 7399971

Claim:
A single-point measurement apparatus for determining a concentration of a high-Z material in a flat sheet material sample comprising: a first nuclear-based sensor device and a second X-ray sensor device for receiving said flat sheet material sample and scanning said flat sheet material sample with electrons for sensing by said first nuclear-based sensor device that is substantially ash insensitive for generating a first sensor response signal and radiation for sensing by said second X-ray sensor device that is sensitive to presence of high-Z material and generating a second sensor response signal; and means for receiving both first and second sensor response signals simultaneously from said first nuclear-based and second X-ray based sensor devices and processing the data obtained from the first and second sensor response signals to extract a weight of the high-Z material additive, the weight of the high-Z material additive being determined in a single scan of the flat sheet material sample, wherein said means for receiving both signals simultaneously from said first and second sensor devices and processing the data implements logic for calculating the weight of the High-Z material (“M”) according to: M=C+A 1 ×ln( R Kr )+ A 2 ×ln( R Kr ) 2 +B 1 ×ln( R Xray )+ B 2 ×ln( R Xray ) 2 +D ×ln( R Kr )×ln( R Xray ) where R 1 is a sensor ratio for each said first and second sensor device, and C, A i , B i , and D are determined constants.