Measurements of absolute x-ray generation efficiency for selected K, L, and M-lines

The absolute efficiency of generation of a selection of K, L, and M- x-ray lines has been measured as a function of the incident electron beam energy. At an overvoltage U=2 this efficiency falls within the range 1E-4 to 1E-7, with K-lines being highest and L-Lines usually being the lowest. It is shown that for all three families of lines the efficiency has a functional variation which has the form A. (U- 1)n, as first suggested by Compton and Allison, where A and n are constants. Values of A and n for the K, L, and M shells are tabulated. The smoothly varying behavior of the efficiency makes it well suited for analytical use and spectrum simulation purposes.