  The energy-spread of the triple-pulse electron beam generated by the
Dragon-II linear induction accelerator is measured using the method of energy
dispersion in the magnetic field. A sector magnet is applied for energy
analyzing of the electron beam, which has a bending radius of 300 mm and a
deflection angle of 90 degrees. For each pulse, both the time-resolved and the
integral images of the electron position at the output port of the bending beam
line are recorded by a streak camera and a CCD camera, respectively.
Experimental results demonstrate an energy-spread of less than +-2.0% for the
electron pulses. The cavity voltage waveforms obtained by different detectors
are also analyzed for comparison.
