@classmethod
def from_norm_at_gamma_1(cls, norm, p1, p2, gamma_b, gamma_min, gamma_max):
    """sets :math:`k_e` such that `spectrum_norm` = :math:`n_e(\\gamma=1)`."""
    return cls(norm.to('cm-3'), p1, p2, gamma_b, gamma_min, gamma_max)
