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 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, and the
    new beam efficiency is set to the one at the  center  of  the  spectrum.
    Otherwise, only the beam efficiency is set to this new value.