Abstract

A simple and fast functional model is proposed to approximate energy loss distributions of charged particles crossing slabs of matter. The most accepted physical models for treating this problem was created by Landau and later improved by Vavilov. Both models depend on complex functional forms with exact solutions that are, by far, too CPU intensive to be directly included in existing Monte Carlo codes. Several authors have proposed approximations with varying degrees of accuracy and performance. This paper presents a compact and efficient form that approximates with enough accuracy the Vavilov distribution and its extreme cases of Landau and Gaussian shapes. Our functional form could be interpreted as a generalization of the basic Gaussian distribution. Some parameter fits are illustrated with various test cases. Our model also represents a simple functional form to use for regression analysis with experimental energy loss data.