Considered is the stimulated Raman scattering of a pump wave by a mildly relativistic electron beam. The electron beam is assumed to be transported along an alternating quadrupole channel. Optimal matched beam Solutions are obtained, and the requirement on the beam emittance is identified. Estimations suggest feasibility of the process for an intense THz radiation source. (C) 2008 Elsevier B.V. All rights reserved.