Ion beam enhancement in 236UO− measurement by AMS using Si powder as the binder

Atomic spectrometry update: review of advances in atomic spectrometry and related techniques

“…Samarium was also used in bracketing solutions to compare the internal and external corrections. Results of the analysis of geological standards produced comparable v 151 Eu : 153 Eu values, but slight differences were observed between the results for different rock groups using the internal Sm correction technique, indicating that Eu fractionation may occur in the geological environment.…”

“…Measurement of U and Pu isotopes using AMS was reported by Hotchkis et al 152 Extended running times were used to provide an overall detection efficiency of better than 1% on 64 × 10 6 atoms, translating to sub-ag detection of Pu isotopes. Kazi et al 153 also used AMS to measure the 236 U isotope, which was suppressed in UO − ion production by ion source poisoning and a large background signal. These problems were circumvented by the addition of Si powder to the UO x –Fe 2 O 3 sample, which resulted in doubling of the 5 nA beam current.…”

“…Stable isotope fractionation in the geological environment, and its potential for systematic mass fractionation correction of isotope ratios, has been a subject of signicant investigation since the introduction of MC-ICP-MS. Lee and Tanaka 138 investigated the potential for Eu isotopic fractionation in natural materials. Chromatographic isolation of Eu from matrix and other REE elements caused column fractionation and a progressively lighter Eu isotopic fraction through the course of elution, with v 151 Eu : 153 Eu changing by >4&. Samarium was added to the post-separation Eu fraction to assess mass fractionation within the sample run using the 150 Sm and 154 Sm isotopes to bracket the Eu isotopes.…”

Atomic spectrometry update: review of advances in the analysis of metals, chemicals and materials

“…Kazi et al undertook tests to improve ionisation efficiency of UO − during 236 U determination. 226 The instrument used was not configured for reliable delivery of a Cs + sputter beam when currents of >0.5 mA was used. To produce a steady stream of UO − , currents closer to 1.5 mA are required.…”