{"thcode":2,"term":{"code":783,"name":"neutron activation analysis","parent":153,"scope":"Sensitive laboratory technique for both qualitative and quantitative analysis of elements in samples.  Target nuclei are bombarded with neutron beams to start nuclear reactions which emit characteristic gamma ray radiations."},"uf":[],"bt":[{"code":153,"name":"chemical analysis","parent":619,"scope":"Chemical techniques used to identify the composition of substances."},{"code":619,"name":"laboratory methods","parent":734,"scope":"Techniques to analyze and test samples in a place equipped and designed for the work."},{"code":734,"name":"methods","parent":1,"scope":"Techniques, methods, procedures, or strategies for research, management, collection, or analysis of scientific information in USGS."},{"code":1,"name":"Categories","parent":null,"scope":"Thematic terms for categorizing information resources.  This thesaurus is intended to support finding and understanding scientific information."}],"nt":[],"rt":[{"code":89,"name":"biochemistry","parent":650,"scope":"Study of chemical processes that occur within or are mediated by living organisms."},{"code":437,"name":"geochemistry","parent":291,"scope":"Study of the distribution of chemical elements and natural compounds on the earth and in the atmosphere and the chemical processes that affect the earth."}]}