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  • 1 Central Research Institute for Physics P. O. Box 49 H-1525 Budapest 114 (Hungary)
  • 2 Institute for Nuclear Sciences Rijksuniversiteit, Proeftuinstraat 9000 Ghent (Belgium)
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Different methods for the determination of thermal-to-epithermal neutron flux ratio are reviewed and nuclear data for commonly used monitor materials and for Zr isotopes are tabulated. It is shown that the use of the94Zr−96Zr isotope pair gives significant improvement in precision while measuring Φthe ratios in the 20<Φthe<200 range. When the single comparator method is applied, the use of the94Zr isotope is suggested as a comparator with the94Zr−96Zr isotope pair for simultaneous flux ratio determination. Theoretical calculations show that the Zr comparator-flux ratio monitor gives better precision and accuracy than does Ru for two-thirds of the isotopes used for analysis in well thermalized (Φthe>100) channels. The Ioth-values for the mentioned Zr isotopes have been experimentally determined and compared with previously published data.