Retarding Potential Quadrupole (RPQ)

Abundance sensitivity is a measure of the tailing of an intense ion beam onto neighboring masses. This can be caused by the scattering of ions, for example by their interaction with residual gas molecules. The result are elevated baselines for masses neighboring bright ion beams.

The Retarding Potential Quadrupole (RPQ) acts as a high selectivity energy filter for ions with disturbed energy or angle. Both Thermo Scientific Neoma MC-ICP-MS and Thermo Scientific Triton XT TIMS can be configured with two RPQ lenses, producing abundance sensitivities of <0.5 ppm and < 20 ppb respectively (at 1 amu either side of ²³⁸U).

The ideal tool for nuclear safeguarding

Reliable analysis of ²³⁴U/²³⁸U and ²³⁶U/²³⁸U provides key information for nuclear safeguarding, but measurement can be difficult due to the very low abundance of ²³⁴U and ²³⁶U. Ion counters offer the lowest quantification limits for these isotopes. Scattered ions from ²³⁸U and ²³⁵U, can bias the measured ratios. The configuration of 2 RPQ lenses allows simultaneous measurement of ²³⁴U and ²³⁶U.