Abstract: The gamma counts, detected corresponding to an incident energy, consist oftwo parts in general. One comes from the region of resonant reaction. It isproportional to the concentration of the nucleus of the target in the resonantregion. The other comes from all the nuclei met by the incident particles in itspath except thoes nucleus of the resonant reaction region, that is non-resonantcount. It is related to the non-resonant cross sections and the target thickness.The non-resonant counts sometimes, account for a large proportion of totalgamma counts. But it has not been taken in to account in the references publishedup to now.