ON THE BETHE-HEITLER FORMULA FOR BREMSSTRAHLUNG,

In dealing with radiation problems one often meets with fairly inconvenient formal obstacles requiring long and tedious explanations which as a rule are omitted in text-books. This obscures considerably the real connection between basic conceptions and end formulae. In the authors opinion the Bethe-Heitler formula for Bremsstrahlung is one of the most striking examples of that sort, the reason for the troubles being mainly that during the process of deduction there is an overcrowding of mutually cancelling terms. The aim of the exposition is to let the final terms shine through at an earliest possible stage. Of secondary interest is to remember how the rest of terms are cancelling. Author