Straggling in energy loss of energetic hydrogen and helium ions

General expressions have been derived for the mean energy loss and straggling of a heavy charged particle penetrating through a thin slice of matter. The main input parameter is a differential energy loss rate that allows for transitions within an arbitrary number of projectile states. Both spontaneous and collision-induced events are potentially induced, but different events are assumed statistically independent. Asymptotically, the mean energy loss is shown to approach a linear dependence on time or path length. The slope is given by the equilibrium energy loss rate, and the intercept at zero path length depends on the incident projectile state. Energy-loss straggling can be split into a collisional part and a contribution from variations in projectile state. The latter turns out to be related to the intercept in the mean energy loss for the pertinent projectile states. Previous results applying to a two-state system have been generalized to an arbitrary number of states. A full evaluation has been presented for a three-state system. A procedure is outlined that allows to empirically determine the magnitude of charge-exchange straggling.

Statistical theory of charged-particle stopping and straggling in the presence of charge exchange

Energy loss and energy loss straggling of fast heavy ions in matter

The recoil separator Lohengrin: Performance and special features for experiments

The penetration of energetic molecules and clusters through solid material and associated radiation effects may be looked at as the sum of events induced by independent atoms. This picture is often adequate as a first approximation but it has definite limitations. The present paper reviews physical effects which cause more or less drastic modifications of this first-order picture. A number of sources of nonlinearities and correlations are identified. The emphasis is laid on stopping, multiple scattering, and collision-cascade kinematics. The discussion is mostly qualitative and based more on intuitive arguments and a few experimental results than on quantitative models.

O. Vollmer

Papers

Der Einfluss von Ladungsfluktuationen auf die Energieverlustverteilung geladener Teilchen