Investigations for isobaric interference of 238Pu at 238U during thermal ionization mass spectrometry of uranium and plutonium from the same filament loading

A novel approach for the determination of 238Pu by thermal ionization mass spectrometry (TIMS) using interfering element correction methodology

“…This Table also includes the signal intensity of major isotope, i.e., of 235 UO + . The 238 U/ 235 U atom ratio determined is higher compared to the certified 238 U/ 235 U atom ratio in NIST-SRM 930 due to small amounts of U present in SRM-947 Pu sample [11]. Table 1b gives the signal intensities of 235 U + and 239 Pu + isotopes (in mV) in different blocks and the data on 238 Pu/ 239 Pu atom ratios obtained during Experiment II.…”

“…However, no significant difference in the isobaric interference correction was observed and the 238 Pu/ 239 Pu atom ratios obtained from the three mixtures are in good agreement with one another as well as with the value expected in the sample. This was attributed to the fact that NIST-SRM 947 originally contains only traces of uranium (about 600 ppm) [11]. The study shows that Pu/U amount ratio need not be known exactly.…”

Critical comparison of radiometric and mass spectrometric methods for the determination of radionuclides in environmental, biological and nuclear waste samples

“…TIMS has been used for the determination of isotopic composition and concentration of different elements including radioisotopes of some elements, such as uranium, thorium and plutonium since 1980's [5,29,[74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89]. In TIMS a small volume (down to 1 μl) of aqueous solution containing the target nuclides or element in the nanogram to microgram range is deposited on a cleaned filament surface (mostly high-purity Re) and evaporated to dryness.…”

Mass Spectrometry in India

“…319,320 Isobaric interferences of 238 Pu and 238 U during TIMS have been investigated. 321 Aggarwal et al developed TIMS for accurate determination at ppm levels of U in Pu, Th and U in pressurized heavy-water reactor fuels. 322 Alamelu and Aggarwal 323 put forward a new method for determination of trace uranium in plutonium by TIMS using enriched 235 U as a spike for monitoring UO + instead of U + to overcome the isobaric interference of 231 Pu at 231 U. Aggarwal studied precise and accurate determination of the alpha decay half-life of 244 Pu by TIMS using 240 Pu and 241 Pu isotopes as reference nuclides.…”

“…324 Similarly, 238 Pu was determined by TIMS using the interfering element correction methodology. 325 Aggarwal et al have studied the formation of atomic (M + ) and molecular ions (MO + ) of uranium and thorium in TIMS of synthetic mixtures with Th/U and have shown its use for isotope analysis of Th and U. 326,327 Aggarwal and colleagues have reported a robust methodology for high-precision isotope analysis of boron (in the form of Na 2 BO 2 + ) by TIMS; Na 2 BO 2 + can be generated by TIMS using NaCl instead of sodium carbonate or NaOH.…”