Preliminary measurements of k0 values for W-186

• Autor(a) principal: BARROS, LIVIA F.
• Data de Publicação: 2018
• Outros Autores: DIAS, MAURO S., KOSKINAS, MARINA F., YAMAZAKI, IONE M., SEMMLER, RENATO, INTERNATIONAL NUCLEAR ATLANTIC CONFERENCE
• Tipo de documento: Artigo de conferência
• Título da fonte: Repositório Institucional do IPEN
• Texto Completo: http://repositorio.ipen.br/handle/123456789/28240
• topic: activity levels; cadmium; data covariances; high-purity ge detectors; neutron activation analysis; tungsten 186

There are various methods of neutron activation analysis, one of these is the k0 Method for quantitative reactor Neutron Activation Analysis (NAA). The k0-NAA procedure is nowadays widely used in numerous laboratories performing NAA all over the world. Among these reactions, 186W(n, ???)187W can be considered important because it can be used for a W concentration measurements. The irradiations were performed at position 24A, near the core of the IEA-R1 4.5 MW swimming-pool nuclear research reactor of the Instituto de Pesquisas Energ??ticas e Nucleares (IPEN-CNEN/SP ??? Nuclear and Energy Research Institute), in S??o Paulo, Brazil. Two irradiations were carried out in sequence, using two sets of samples: the first with a cadmium cover around the samples and the second without, in a total of three data sets with and without Cd cover performed in 2014 and 2015. The activity measurements were carried out in an HPGe gamma-ray spectrometer. Standard sources of 152Eu, 133Ba, 60Co and 137Cs supplied by the IAEA were used in order to obtain the HPGe gamma-ray peak efficiency as a function of the energy. The covariance matrix methodology was applied to all uncertainties involved. The preliminary values of k0 for 186W(n, ???)187W reaction for the gamma transition energy of 479.53 keV was 3.17x10-2(5), for 618.77 keV was 9.08x10-3(15) and for 685.77 keV was 3.88x10-2(6). These preliminary values for k0 have been compared with the literature.