An improved raster magnet driver for a linear particle beam is based on an
H-bridge technique. Four branches of power HEXFETs form a two-by-two
switch. Switching the HEXFETs in a predetermined order and at the right
frequency produces a triangular current waveform. An H-bridge controller
controls switching sequence and timing. The magnetic field of the coil
follows the shape of the waveform and thus steers the beam using a
triangular rather than a sinusoidal waveform. The system produces a
raster pattern having a highly uniform raster density distribution,
eliminates target heating from non-uniform raster density distributions,
and produces higher levels of beam current.