The calculation of low energy He ion stopping powers

It is shown that the ratio of He to H stopping powers is virtually independent of target element, implying that only low velocity target electrons are involved in stripping the ion of its electrons. The effective charge of H and He ions in all elements is evaluated, and is shown to be almost target independent. By using different effective charge values for ions traversing solids and gases, the stopping of He in each physical state has been calculated for all elements. These values are compared to experimental values and to the tables of Northcliffe-Schilling. © 1978.