NITROGEN DISTRIBUTION MEASUREMENTS BY NEUTRON-INDUCED AUTORADIOGRAPHY

A method utilizing plastic track detectors was developed to determine the nitrogen distribution and concentration in the presence of boron i n metals. Experiments were performed at the UVAR (cadmium ratio simila r to 25) and the NIST Reactor (cadmium ratio similar to 3000). The min imum detectable concentration of nitrogen at a given concentration of boron has been estimated using the detector's response to B-10(n,alpha )Li-7 reaction products in terms of track size distribution. The capab ility of the technique to detect nitrogen in the presence of boron has been demonstrated using 316L stainless steel with a nitrogen concentr ation of similar to 560 ppm and a boron concentration of similar to 0. 86 ppm.