Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Comparison of Resonance Ionization Mass Spectrometry Systems for the Determination of 135Cs/137Cs Ratios



Leticia Pibida, C A. McMahon, W Nortershauser, B A. Bushaw


The performance of the Resonance Ionization Mass Spectrometry (RIMS) system at the National Institute of Standards and Technology (NIST) has been compared to a similar system at Pacific Northwest National Laboratory (PNNL). Efficiency and selectivity measurements were performed with both systems and compared to conventional thermal ionization mass spectrometry (TIMS). Determination of the 135Cs/ 137Cs ratio was performed using single-resonance excitation 6s 2S1/2(F=4)-> 6p 2P3/2(F' = 5) with an extended cavity diode laser followed by photoionization with the 488 nm line of an argon ion laser. Optical selectivity of more than 2 orders of magnitude against stable 133Cs was attained for 135Cs and 137Cs for both systems with an overall selectivity of 109 for the PNNL system and 108 for the NIST system. Over all efficiencies of 2x10-7 were measured for the PNNL and NIST systems respectively. Measurements to determine the chronological age of a nuclear burn-up sample have been performed using both RIMS systems as well as TIMS.
SPIE Meeting


<sup>135</sup>Cs/<sup>137</sup>Cs isotope ratios, cesium, mass spectrometry, resonance ionization, trace analysis


Pibida, L. , McMahon, C. , Nortershauser, W. and Bushaw, B. (2008), Comparison of Resonance Ionization Mass Spectrometry Systems for the Determination of <sup>135</sup>Cs/<sup>137</sup>Cs Ratios, SPIE Meeting (Accessed March 5, 2024)
Created October 16, 2008