Use of resonance ionization mass spectrometry for determination of Cs ratios in solid samples.

A method to quantitatively determine the radionuclidic content of complex samples with a minimum of chemical preparation has been under development at the National Institute of Standards and Technology (NIST). Based on earlier studies with resonance ionization mass spectrometry (RIMS), a graphite furnace was added to the RIMS system at NIST. Efficiency determinations for 133Cs in solution and isotopic ratio measurements of cesium (135Cs/137Cs) for an NIST nuclear burn-up sample using RIMS and for a sediment natural matrix standard using thermal ionization mass spectrometry are presented.