Accurate nuclear transition data determined by prompt (n,/spl gamma/)-spectrometry

Prompt (n,/spl gamma/)-spectrometry is an on-line measurement for the determination of characteristics of nuclei (atomic masses, cross sections, level schemes, etc.) and nondestructive investigation of the isotopic composition (and, therefore, of the element composition) of any sample. The thermal neutrons are captured in the sample according to their isotope-specific cross sections and cause an high internal excitation of the nuclei concerned. This leads to an immediate rearrangement of the nucleons in a new state most favourable with respect to energy, and the excess energy is dissipated by prompt emission of electromagnetic radiation in the form of characteristic /spl gamma/-quanta. The process takes place for all isotopes (contrary to the neutron activation analysis), is nondestructive and has no need for sample preparation (contrary to the mass spectrometry). Moreover it is independent of the sample dimensions and its state of aggregation.