Walter H. Barkas

Walter H. Barkas (* 1912 in Portland (Oregon) † 28 March 1969) was Professor of Physics at the University of California, Riverside from 1965 on. He specialized in the use of nuclear emulsions, i.e., photographic plates having a thick sensitive layer, for purposes of Particle physics.

Together with his collaborators, he discovered the difference in range between positive and negative mesons of the same initial energy, and he ascribed this effect to the difference in stopping power between positively and negatively charged particles. Hence, this difference is called "Barkas effect" or "Barkas-Andersen effect", see Bethe formula.

Literature

*Barkas W.H., Dyer J.N., Heckmann H.H.: "Resolution of the Σ^--mass anomaly", Physical Review Letters 11 (1963) 26

*Sigmund P.: "Particle Penetration and Radiation Effects, General Aspects and Stopping of Swift Point Charges", Springer Series in Solid State Sciences Vol. 151, Springer Berlin Heidelberg (2006)