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  • 1 Belgian Nuclear Research Centre SCK·CEN Boeretang 200 B-2400 Mol Belgium
  • | 2 IRMM Institute for Reference Materials and Measurements, European Commission Retieseweg 111 B-2440 Geel Belgium
  • | 3 Ghent University Laboratory of Analytical Chemistry, Institute for Nuclear Sciences (INW) Proeftuinstraat 86 B-9000 Gent Belgium
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Abstract  

The thermal to epithermal neutron flux ratio (f) and the deviation of the epithermal neutron spectrum from the 1/E shape (α) are essential parameters for the correct application of k0-standardized neutron activation analysis. Several methods are applied for the determination of f and α. They are based on Cd-covered multi-monitor or on bare-irradiations methods. The recently developed and characterized synthetic multi-element standards (SMELS) were designed as a validation tool for the proper implementation of the k0-NAA method in a laboratory. In particular, SMELS Type III contains Au and Zr, thus allowing the direct determination of f and α. It could, therefore, replace the traditional flux monitors. Furthermore, it could be used as a quality control material to monitor the stability of the irradiation facility and the detector. This paper presents the accuracy of the f and α determination and the feasibility of quality control using SMELS for irradiation channel Y4 of the BR1 reactor.