An analytic formula for continuous slowing-down approximation ranges of 1-keV to 1-GeV electrons

An analytic formula has been developed to express the continuous slowing-down approximation ranges of electrons in the energy region from 1 keV to 1 GeV. Values of adjustable parameters in the formula have been optimized to the data generated by the NIST-database program EPSTAR. The media considered are the representative elemental solids of Be, C, Al, Cu, Ag, Au and U. The maximum deviation of the formula from the data is 2%. Comparison of the formula with NIST-database values has been made for other elemental solids (Si, Ti, Fe, Ge, Mo, Sn, Gd, W, Pt and Pb) and compounds (polyethylene, polyethylene terephthalate, polymethyl methacrylate, polystyrene, sodium iodide and water), effective atomic number and atomic weight being used for the compounds. For all these materials, the maximum deviation is less than 3% in the energy region above 100 keV. (author)