Preparation and Characterization of Neutron Dosimeter Materials

The Isotopes Division of Oak Ridge National Laboratory has developed procedures for providing accurately defined deposits of ²³⁹ PuO₂ and ²³⁵ UO₂ for use in precision neutron cross-section measurements. Encapsulated samples of ⁶Li, ¹⁰B, ⁴⁵Sc, ²³²Th, ²³⁵U, ²³⁸ U, ²³⁷Np, ²³⁸Pu, ²³⁹Pu, and ²⁴¹ Pu for use as neutron monitors in reactors can also be provided. These dosimeters are used to determine integral reaction rates from which the neutron energy spectrum, flux, and fluence at particular locations within a reactor can be computed. Methods for the preparation and characterization of reactor dosimeters and other reaction rate samples provide an accuracy of ≤±1% at the 95% confidence level (CL).