  The spectrum of relativistic electron bunches with large energy dispersion is
hardly obtainable with conventional magnetic spectrometers.
  We present a novel spectroscopic concept, based on the analysis of the
photons generated by Thomson Scattering of a probe laser pulse inpinging with
arbitrary incidence angle onto the electron bunch.
  The feasibility of a single-pulse spectrometer, using an energy-calibrated
CCD device as detector, is investigated. Numerical simulations performed in
conditions typical of a real experiment show the effectiveness and accuracy of
the new method.
