CONSTRUCTION AND USE OF EPOXY AND DIATOMACEOUS EARTH MATRICE STANDARDS IN CALIBRATION OF SOLUTION ASSAY INSTRUMENTS: A PRELIMINARY STUDY

Solution Assay Instruments (SAIs) are used in the Los Alamos National Laboratory's plutonium facility to perform nondestructive assays of plutonium bearing solutions. These systems use custom software to provide spectral analysis of the gamma ray peaks and give measurement results as plutonium mass (grams) and plutonium concentration (grams per liter). The present calibrations of the systems are completed using standards of a known concentration. Problems in storage of the solution standards exist which necessitate the dispensing of new standards for each calibration regime. A comparison of SAI measurement results on a set of solution standards and on the solid bias standards is presented. The SAI instrument utilized in taking measurements operates with the constants derived from calibration measurements of solid standards. The method used for construction of the solid standards is included Results of the study will show whether using the solid (epoxy or diatomaceous earth matrix) standards in calibrations would be an acceptable alternative to using solution standards. A reusable set of solid calibration standards has advantages such as cost saving, waste reduction, and time saving.