Low-Level Detection of Actinides by Laser Resonance Photoionization

Abstract

Actinides, detection of trace amounts /Laser resonance ionization mass spectrometry /Isotope analysis of plutonium AbstractLaser resonance ionization mass spectrometry has been investigated as a method for the detection of trace amounts of actinides. High sensitivity and selectivity can be achieved by three-step photoionization followed by time-of-flight mass analysis. The laser system for photoionization consists of three dye lasers which are pumped simultaneously by a copper vapor laser. For mass determination a time-of-flight spectrometer with a mass resolution of about 1500 is used. By ionization via autoionizing states an overall efficiency of 4 X 10"' was determined for 23 ®Pu yielding a detection limit of less than 10 7 atoms. Isotope ratio measurements have been performed with synthetic plutonium samples.

High efficiency laser resonance ionization of plutonium

“…Three-color, three-step resonant ionization was first reported by Peuser et al 22 using three pulsed dye lasers, which showed a detection efficiency of 10 . Since then, there have been extensive studies on RIMS as an analytical instrument for trace analysis of Pu and other radioactive elements 17 , 23 – 31 , for fundamental studies of actinides 32 , and in combination with other techniques such as SIMS 30 , 32 , 33 , fast chemical separation 29 , and laser ablation 34 . Worden et al 35 studied two- and three-step resonance ionization pathways using dye lasers.…”

Alpha Spectrometric Determination of Trace Level of 239-240Pu and 238Pu Uranium Compounds and Solutions

“…Interest has also tumed to various mass spectrometry techniques (ICP-MS [10,11], TIMS [12,13]), but those methods are not really adapted for a matrix where uranium is the principal constituent because of isobaric interfering effects. Only Resonance Ionisation Mass Spectrometry (RIMS [14]) would authorize plutonium measurement with remaining uranium in the sample. However, Instrumentation for RIMS does not exist in many laboratories and as a consequence, for the moment, RIMS is not * Author for correspondence.…”