“…The relevant phenomena associated with backscattering measurement, are either coherent or incoherent ones. The first one results from interference caused by the double passage of the wave through the same particle Ishimaru, 1984, 1985;Wolf et al, 1988;de Wolf, 1991;Helfenstein et al, 1997). The angular width of the measured intensity peak is proportional to the transport mean free path…”