MODIFY BEAM_EFF

        LAS\MODIFY BEAM_EFF Value
        LAS\MODIFY BEAM_EFF /RUZE B0 Sigma

    Change the beam efficiency.

    The first syntax allows to define the new beam efficiency from a  single
    value  for  the  whole spectrum. If the beam efficiency previously had a
    non zero value, the spectrum intensities and affected header  parameters
    are  rescaled  according  to the old and new values. Otherwise, only the
    beam efficiency is set to the new value.

    The second syntax allows to use the Ruze's equation, which is more suit-
    able for large band spectra:
        Beeff(lambda) = B0*exp(-(4*pi*Sigma/lambda)**2)
    B0  is the scaling factor with no units (between 0 and 1), and Sigma the
    width factor in microns.
    If the beam efficiency previously had a non zero value, a rescale factor
    is evaluated for each channel and is applied to the intensities, the new
    beam efficiency is set to the one at the center of the spectrum, and the
    affected  header  parameters  are  rescaled according to this new value.
    Otherwise, only the beam efficiency is set to this new value.