                Example GB04 : bremsstrahlung splitting
                ---------------------------------------

    This example illustrates the use of the generic biasing classes to create
a bremsstrahlung splitting technique.
    Note that the EM package also offers a bremsstrahlung splitting, that is
built-in to the package.


                           GB04BOptnBremSplitting

    The bremsstrahlung splitting is implemented in the GB04BOptnBremSplitting
class (BOptn = Biasing Operation), which acts on the final state creation
of the bremsstrahlung process.


                           GB04BOptrBremSplitting

    Decisions when to apply the GB04BOptnBremSplitting biasing operation are
taken by the GB04BOptrBremSplitting (BOptr = Biasing Operator) operator. This
one also configures the biasing operation, setting it the splitting factor
and its behavior regarding electrons to be biased : only the primary one, or
all, and only the first bremsstrahlung operation, or all. These are
controled by this specific example commands:

	  /GB04/biasing/setSplittingFactor [N splitting]
	  /GB04/biasing/biasPrimaryOnly    [true/false]
	  /GB04/biasing/biasOnlyOnce       [true/false]


    The geometry is minimal : a single volume to which an instance of
GB04BOptrBremSplitting is attached to.

    The wrapping of physics processes by G4BiasingProcessInterface processes
is simply handled by the G4GenericBiasingPhysics physics constructor, as shown
in the main program.
