QUALITY ASSURANCE PROCEDURES IN MASS SPECTROMETRY

Thermal ionization and electron-impact gas mass spectrometry are primary methods of measurement for the determination of isotopic abundances and amount of substances of nuclear materials. As such, they are capable of providing direct traceability to SI units, a universally-accepted reference base. In order to realize this level of traceability, certain calibrations must be applied on a routine basis and a series of protocols must be implemented to assure a high level of continued traceability. A general description of these protocols and calibrations is presented, providing an overview of approaches taken by a federal metrology laboratory. In addition to a description of general protocols, a specific procedure for mass bias correction is described that is used to improve the accuracy od repeated measurements.