  An explicit solution of the stationary one dimensional half-space boundary
value problem for the linear Boltzmann equation is presented in the presence of
an arbitrarily high constant external field. The collision kernel is assumed to
be separable, which is also known as "relaxation time approximation"; the
relaxation time may depend on the electron velocity. Our method consists in a
transformation of the half-space problem into a nonnormal singular integral
equation, which has an explicit solution.
