On 'measurements' of radiation damage by backscattering experiments

It is generally meaningless to extract a measurement of the 'number of disordered atoms' from a backscattering experiment. The only case where this is a measurable quantity is that of amorphous regions inbedded in a perfect crystal. In all other cases (particularly in metals), a backscattering experiment can yield only an indication about the degree of lattice disorder. The number and nature of defects cannot be determined by a backscattering experiment, but it is suggested that the energy dependence of the dechanneling could be of some help to distinguish between different possible types of defects. (author)